Book Preservation Technologies

May 1988

NTIS order #PB88-212410
Recommended Citation:

U.S. Congress, Office of Technology Assessment, Book Preservation Technologies, OTA0-375 (Washington, DC: U.S. Government Printing Office, May 1988).

Library of Congress Catalog Card Number 88-600521

For sale by the Superintendent of Documents

U.S. Government Printing Office, Washington, DC 20402-9325

(order form can be found in the back of this report)
Foreword

Even in today’s high-tech society, books are the principal records of human civilization. Over the centuries, books have become the most reliable and permanent records available, but, in the last century, that reliability has been threatened by the use of ‘modern,

acidic paper that becomes brittle and unusable in a relatively short time. Books printed

since 1850 are deteriorating en masse in libraries the world over. Nowhere is this problem

more severe than in the U.S. Library of Congress; a major preservation program addressing it was initiated in the early 1970s. The Library’s mass deacidification process is now

being tested at a pilot plant, and planning is underway to design and construct a full-scale

facility that could treat about 1 million books each year.

This assessment analyzes the problem of acid deterioration of books and the program

underway at the Library of Congress. The program at the Library involves the chemical

treatment of books in a unique and effective process that, however, also presents some

new engineering and safety concerns. Because of these concerns, the House of Representatives Committee on Appropriations requested this independent review of the Library’s

system and other available or potential processes. OTA has evaluated the Library’s process and program with a focus on effectiveness and safety, and compared it to available

alternatives. OTA has also developed information and analyses useful to other major libraries

in the Nation that are faced with the same problem of preserving valuable books and papers.

OTA is grateful for the assistance provided by the assessment advisory panel, workshop participants, and other consultants, and acknowledges the full cooperation of the Library of Congress in responding to requests for information, arranging meetings with its

consultants, and reviewing materials. OTA also appreciates the efforts made by the developers of other deacidification processes to make available the most up-to-date information.

U JOHN H. GIBBON S

Director

. . .

Ill
Norbert S. Baer

New York University

George Bierkamper

School of Medicine

University of Nevada

Helen Burgess

Canadian Conservation Institute

George M. Cunha

Conservation Consultant

Book Preservation Technologies

Advisory Panel

James J. Stukel, Chairman

University of Illinois, Chicago, Illinois

G. Larry Eitel

Stone & Webster Engineering Corp.

Carolyn Harris

Columbia University

Robert M. Hayes

University of California, Los Angeles

Jerry Lott

University Technologists, Inc.

Thomas H. Magness III

EBASCO Services, Inc.

NOTE: OTA appreciates and is grateful for the valuable assistance and thoughtful critiques provided by the advisory panel

members. The panel does not, however, necessarily approve, disapprove, or endorse this report. OTA assumes full

responsibility for the report and the accuracy of its contents.

iv
OTA Book Preservation Technologies Project Staff

John Andelin, Assistant Director, OTA

Science, Information, and Natural Resources Division

Robert M. Niblock, Oceans and Environment Program Manager

Peter Johnson, Project Director

Project Staff

Joan Ham, Analyst

John Moteff, Analyst

Contractor

David N.S. Hon

Administrative Staff

Kathleen A. Beil

Sally W. Van Aller
Acknowledgments

The following individuals and organizations provided special assistance and advice to OTA in this study by

participating in workshops, providing information and analyses, demonstrating equipment and processes, or reviewing and commenting on OTA draft reports.

Jean-Marie Arnoult

Bibliotheque Nationale

Gerhard Banik

Osterreichischer Nationalbibliothek

Scott Bennett

Northwestern University Library

Gregor R. Campbell

Interleaf, Inc.

Homer Carhart

The Naval Research Lab

D.W.G. Clements

The British Library

Thomas P. Commeau

Champion International Corp.

Robert Faltynek

National Bureau of Standards

U.S. Department of Commerce

Howard H. Fawcett

K.F. Foster

National Archives of Canada

Sy H. Friedman

Library of Congress

Yashpal P. Kathpalia

George B. Kelly, Jr.

Terry O. Norris

Edwin Parks

National Bureau of Standards

U.S. Department of Commerce

Donald K. Sebera

Library of Congress

Hillary M. Sharpe

B.G. Robertson Laboratories, Ltd.

Subhas Sikdar

National Bureau of Standards

U.S. Department of Commerce

Richard D. Smith

Wei T’o Associates, Inc.

Peter G. Sparks

Library of Congress

Richard E. Spatz

NASA Goddard Space Flight Center

Princeton University Library

S & B Engineers, Inc.

Susan D. Kamp

EBASCO Services, Inc.

Texas Alkyls, Inc.

vi
Contents

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Part I: The Library of Congress Mass Deacidification Program . . . . . . . . . . . . . . . . . 9

Chapter 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Chapter 2. The DEZ Process and its Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter3. Effectiveness of the DEZ Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Chapter 4. Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Chapter 5. Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Chapter 6. Health and Environment Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Part II: Comparison of Alternatives for Book Preservation & Deacidification . . . . . 83

Chapter 7. Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Appendix A. Definition of Tems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................107

Appendix B. Library of Congress’ Operating Cost Estimates for Full-Scale Mass

Deacidification Facility, November 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...109

Appendix C. Library of Congress’ Capital Cost Estimates for Full-Scale Mass

Deacidification Facility, November 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....112

Appendix D. Suggestions for Standard Paper Testing for Deacidification Quality

Control by National Bureau of Standards, 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..,.116

Appendix E. List of Papers and Presentations on the DEZ Process by the Staff of the

Library of Congress From 1974-86 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........117

vii

Introduction

PURPOSE OF

Millions of books at the Library of Congress and

other libraries around the world are deteriorating.

Many books published since the mid- 1800s are currently, or will soon become, too fragile to handle.

The paper these books are written on becomes brittle

over time and crumbles. The primary cause of this

deterioration is acid. Chemicals used in the manufacture of paper from wood pulp, which stay in the

paper, convert to a variety of acids and slowly destroy the strength of the paper’s fibers over time.

Other factors such as oxidation, varying or extreme

temperature and humidity, exposure to light, air

pollutants in storage areas, and the amount of use

also contribute to the destruction of the books.

The Library of Congress has been working to

solve the problem of acid paper in books since the

early 1970s, developing a mass deacidification process that would inhibit the deterioration of book paper. About 25 percent of the 14 million books at

the Library of Congress are too brittle for normal

use. The main purpose of the Library of Congress

program is to preserve and extend the life of paper

materials before they reach this brittle, unusable

condition. This would involve deacidification of new

materials coming into their collection as well as existing materials not yet damaged beyond use.

Other libraries and researchers have also worked

on this problem and small-scale processes are in use.

The purpose of this assessment is to evaluate the

appropriateness of the system under development

by the Library of Congress and compare it to other

available or potential processes. Although this report focuses mainly on the Library of Congress,

it will hopefully assist the library community, in

general, with decisions on how to cope with the acid

book problem. Another recent report on this subject is titled ‘‘Mass Deacidification for Libraries’

THIS STUDY

What Is The Library of Congress?

● The largest center for information storage in the

world.

● Collections include 19 million volumes and 58

million pieces of stored data on phonograph

records, motion picture reels, computer tapes,

manuscripts, maps, prints, and photographs.

● Three Canons of Selection established in the

1940s to define the collections:

—materials necessary to the Congress and to

the U.S. Government officers in performance

of their duties;

—materials that express and record the life and

achievements of the people of the United

States; and

—records of other societies and peoples, especially those of most immediate concern to the

people of the United States.

● Less than 25 percent of the collection is in

English.

● Serves five audiences:

1. Congress— Library provides research support, policy analysis, and training through

the Congressional Research Service;

2. professional library world—Library provides

cataloging and other bibliographic services

and leadership on library technology;

3. executive agencies—Library provides information resources;

4. scholars—Library provides research collections and support; and

5. creative world—Library protects products

and preserves traditions.

SOURCE Charles A. Goodrum and Helen M’ Dalrvmplc, 7-he I.]hr.+r} [)/

Congress (Boulder, CO Westvlev Press, 1%32), p ‘?37

by George M. Cunha, published in Library Technology Reports of the American Library Association.

THE ACID BOOK PROBLEM

The problem of acid deterioration of library books recently developed

and other assets is not new. In 1898, an international conference was organized to discuss the poor IK. G. Schmude, “Can

of Paper Deterioration,

quality and lack of permanence of paper made by No. 1, February 1984.

wood pulping processes. 1 DurLibrary Collections Survive? The Problem

The Australian Library Journal, vol. 33,
2

ing the 1930s a number of researchers began to study

the problem more systematically, establishing a

correlation between the acid content of paper and

its lack of permanence, and began experimenting

with new papermaking processes for making acidfree papers. In the 1950s, the Council on Library

Resources became a leading supporter for research

on paper permanence, eventually leading to standards for permanent paper.

Although there has been an awareness of the problem for almost 100 years, a more global sense of

urgency has only recently developed. The rapid increase in the size of library collections beginning

in the late 19th century has created for the libraries

How the Library of Congress

Obtains Materials

1. Copyright Office receives about 130,000 books,

230,000 periodicals, and tens of thousands of

sheets of music each year. It also receives maps,

motion pictures, telephone directories, phonograph records, computer tapes, ballet notations, etc. All of these materials are received

free of charge.

2. Government Exchange provides records of

affairs from Federal, State, major cities, and

foreign governments, as well as international

government organizations. About 4 million

publications are obtained through these channels each year. None of these materials are purchased. The Library obtains non-Federal materials by trading Federal publications.

3. Gifts include personal papers given outright or

deposited with the Library. In 1980, about 1.8

million pieces were received.

4. Purchased Materials include:

● newspapers —330 U.S. and 1,000 foreign;

• foreign magazines—about 30,000;

● foreign books—includes significant nonfiction and representative literature;

. research materials for the CRS Library; and

● blind and physically handicapped collection,

this is the largest portion of the purchase

budget, in 1980, about 1.9 million volumes

were purchased for about $35 million.

SOURCE Charles A Coodrurn and Helen W Dalrymplc, The Library of Cum

grrss ( Bouhlrr, C() West. Iew Press, 1982), p 337

and other institutions a crisis of enormous proportions that is now ‘‘coming of age.

Although the materials and techniques used to

make paper have changed, the underlying principles involved have changed little in 1,700 years.

Materials containing cellulose (e. g., mulberry, flax,

cotton, wood) are beaten and macerated in water

creating pulp. The pulp is then formed in a mold

and dried, leaving behind a mat of cellulose fibers.

The water that remains after drying holds the matted fibers together. Additional substances are added in the processing that give paper its other familiar qualities. Sizing agents are added to reduce the

penetration of liquids, making it possible to print

without blotting. Fillers are sometimes added to

make the paper whiter and opaque. Dyes, pigments,

and strengtheners can also be added.

Paper can be extremely stable, maintaining its

durability for centuries if taken care of properly.

There are many examples of books published as

far back as the 1500s that are still in fine condition.

Paper permanence, the ability of paper to maintain its durability over time, has slowly declined

over the years, however, to the point where we are

lucky if the vast majority of “modern’ papers, paper made since the mid-19th century last 50 years.

The more rapid deterioration of modern paper

has been attributed to acids that accumulate in the

paper. The source of the acids are chemicals that

are either introduced during the papermaking process or are introduced subsequently from the environment. The acids attack the cellulose that makes

up paper, breaking it into smaller and smaller pieces,

until the paper has lost all of its durability.

Actually, the use of acid-producing materials in

papermaking began as early as the late 17th century when European papermakers began to use

alum (aluminum sulfate) in addition to animal gelatin as a sizing agent. Alum, in time, can be converted to sulfuric acid. Measurements of 400-y earold papers revealed that those with alum sizing have

a higher acid content than those papers that just

used animal gelatin or no sizing at all. z

2W.J. Barrows Research Laboratory, Inc., “Permanence/Durability

of the Book, Vol. VII: Physical and Chemical Properties of Book Papers,

1507 -1949,” 1974.
3

It was not until a series of innovations in the 19th

century, however, that the acid content of paper

rose dramatically. Alum-rosin sizing was introduced

in 1803, replacing gelatin and gelatin-alum sizing.

Alum-rosin sizing required excess alum, increasing the amount of this acid producing substance

in the paper. In the mid-19th century, rags and linen

were replaced by wood as the major cellulose feedstock. Wood pulp contains lignin and hemicellulose that easily breakdown in air, causing discoloration and forming acidic compounds. In addition,

wood cellulose is more susceptible to acid reactions

than the cotton cellulose derived from rags and linen.

By the end of the 19th century, chemical wood pulping processes were developed to remove lignin (because of the discoloration it caused) but did so by

using acidic solutions. As a consequence of these

innovations, paper produced since the mid- 19th century can have an acid content today 100 times

greater than paper produced in the 1500s.3

The effect of this higher acid content can be devastating. In 1959, the William J. Barrow Research

Laboratory, with support from the Council on Library Resources, measured the durability of books

published in the United States between 1900 and

1949.4 A 500-book sample was taken from libraries

— 3

1 bici.

4W.J. Barrow, ‘‘ Deterioration of Book Stock, Causes and Renledlcs,‘‘ Randolph Church (cd. ) (Richmond, VA: I’irginia State Library 195!3)

in and around the Richmond, Virginia area where

the Laboratory was located. The study determined

that 39 percent of the books published between 1900

and 1939 had already become very weak; the pages

would crack after moderate use and would probably become too brittle to handle at all in another

25 years. Furthermore, another 49 percent of the

books had a durability less than that of newsprint,

the weakest paper used for printing.

Numerous libraries have sampled their collections

and found the same sobering statistics (e. g., University of California, Yale, and Stanford). Yale’s study

concluded that 43 percent of the libraries’ 9 million books are brittle and another 44 percent have

a high acid content.5

The extent of the problem nationwide is staggering. The Association of Research Libraries (ARL)

has estimated that 75 million books in the Nation’s

research libraries alone are endangered. Although

many of these are still in print and can be repurchased by libraries, the ARL estimates that over

the next 20 years, at least 3.3 million volumes must

be transferred to another format if the the information they contain is to be saved. G

‘Gay Walker, Head of the Preservation Department, Yale Un iversity Library, personal correspondence, July 10, 1987.

bCouncil on Library Resources, “Brittle Books: Reports of the Committee on Preservation and Access, Washington, DC, 1986.

APPROACHES FOR ADDRESSING THE ACID BOOK PROBLEM

Acid-Free Paper Production

The most obvious solution to the acid book problem is to make and use alkaline (acid-free) paper.

New mass-producing technologies for such papers

have been developed since the 1930s. Many university publishing houses now require the use of alkaline paper, and libraries have lobbied papermakers

and publishers to move in this direction. However,

there are a number of economic obstacles that impede the transition and it appears that only 157 to

258 percent of the book paper produced in the United

States is alkaline. The prospects for producing more

alkaline paper in the future will be discussed later

in this report. Even if widespread use of acid-free

paper occurred tomorrow, however, the problem

remains of how to preserve the paper or the information that has already been accumulated,

Preservation Techniques

Libraries are no strangers to preservation. Over

40 institutions nationwide are actively pursuing

7C,J. Shahani and W.K. Wilson, ‘ ‘Preservation of Libraries and

Archives, American Scientist, vol. 75, May-June 1987, referencing

R.G. Johnson, “U.S. Alkaline Fine Papermaking To Experience Slow

But Steady Growth, Pulp and Paper, December 1986.

“ ‘Report on Library of Congress Conference on Paper for Book

Longevity, ” Library of Congress Information Bulletin, vol. 40, No.

13, Mar, 27, 1981.
4

How the Library of Congress

Selects Materials

● About 10 million items are received by the Library each year, of these about 1.5 million items

are selected for inclusion in its collections.

● Selection policies are based on subject matter,

four levels of retention (i.e., comprehensive, research, reference, minimal), specific decisions

about a subject and specific decisions about individual items.

● Routine selection involves review by about 30

specialists. About 30 other people are involved

in processing the book and getting it onto the

shelves.

● Most domestic books are obtained through the

Copyright Office. The Library retains the

majority of hardback books, a sampling of

paperbacks, and many college textbooks.

Almost no texts for elementary or high school

are retained.

● Most foreign books are selected after purchasing the same publications as the largest library

in the country or by working with a single dealer

in a particular country.

preservation programs, 9 spending millions of dollars each year. The nation-d libraries and archives

of many other countries are also actively engaged.

Preservation involves a wide range of activities,

including the general conservation of important and

rare books and documents, environmental control,

and the training of staff in proper storage and handling procedures. Many techniques have been developed and are in use today. Aside from the environment control techniques and general handling

and storage procedures, many of these techniques

are essentially manual operations performed one

page at a time, are very time-consuming, and often

require skilled practitioners. The size of the acid

book problem now and in the future, however,

dwarfs the current efforts and will require adapting existing techniques or developing new ones.

There are two aspects to dealing with the acid

book problem—preserving the information that exists on materials that have already become brittle,

94 ~ M~lion~ & Bookg Disintegrating in Nation’s Libraries, Anderson Daily Buletin, Oct. 23, 1986.

and preserving those materials that have not yet

become brittle. This study will focus on deacidification of materials before they become brittle and

will not cover the technologies or techniques that

have been developed to transfer the information to

another media or format. However, a short discussion on paper strengthening follows here.

Strengthening

In cases where it is desirable to maintain the original format, embrittled materials can be handled by

laminating or mounting, An early technique for

laminating brittle paper was to sandwich it between

finely woven silk, using starch or paraffin as an adhesive. During the 1930s, the National Bureau of

Standards developed a technique that sandwiched

brittle paper between two sheets of cellulose acetate, the cellulose acetate was bonded to the paper

by heating and pressing. The Library of Congress

developed a technique that encapsulates the paper

between two sheets of polyester film (e. g., mylar) .10

The film is bonded around the edges but is not

bonded to the paper, therefore, the technique is reversible.

Although these techniques can be automated to

some extent, they can only be done a single sheet

at a time. Books would have to be unbound and

then rebound. Costs are high and the process is usually limited to preserving rare books.

New techniques are being developed that would

actually strengthen the paper by polymerization.

This essentially reverses the breakdown of cellulose fibers by forming physical links between the

broken cellulose fibers, restoring the paper’s flexibility. Of course, this is a short-term solution for

acidic papers unless deacidification is also part of

the treatment.

Deacidification

For materials that have not yet become brittle,

techniques have been developed to neutralize the

acids that cause the paper to deteriorate and to deposit an alkaline buffer that acts as a reserve to neutralize any acids that may continue to form. The

objective is to extend the life remaining in the paI°C.J. Shahani and W.K. Wilson, “Preservation of Libraries and

Archives, ” American Scientist, vol. 75, May-June 1987.
5

Photo credit: Library of Congress

Manual book deacidification technique treats

one page at a time.

per at the time it is treated. The history of the development of single sheet, spray and mass deacidification techniques, including the contributions of

the William J. Barrows Research Laboratory, are

described in greater detail in other documents.ll

Most of the deacidification techniques in use

today are manual liquid solution processes. Sheets

of paper are either dipped in or sprayed with a solution containing one or more alkaline compounds.

The compounds precipitate out of solution, neutralizing the acids. Excess precipitate is deposited

as a buffer. The alkaline compounds are normally

magnesium or calcium carbonates and the solvents

can be aqueous or non-aqueous.

Current manual techniques are time-consuming

and expensive. The paper must be treated one page

at a time. Books must be unbound if they are dipped

into the solution. Each page must be tested to make

sure that inks, colors, etc. are compatible with the

solvents being used. Some solvents not only dissolve the alkaline compounds used to neutralize the

acids but will also dissolve certain inks and pigments

and other book materials. These processes are painstaking operations and demand highly skilled practitioners. They are normally used only for rare books

where the value of maintaining the original format

is greater than the cost of treatment.

1 j SCc c ,J. Shahanj and W. K. Wi]s,on, ‘‘ Prmen.at ion of Libraries

and Archives, ” American Scientist, vol. 7.5, hfay-June 1987, pp. 240-

251 ; and George hf. Cunha, ‘‘ Mass Dcacidification for Libraries,

I,ibrarj ‘l”cchnolo,q Reports, .May-<June 1987, pp. 363-477

The lack of financial resources, time, and manpower make it impossible for most of these preservation processes to be of much use in tackling the

more general acid book problem. Over the last 10

to 15 years, mass deacidification techniques have

been under development that would treat many

books at once. Such techniques would not only increase the number of books that could be treated,

from tens of thousands to hundreds of thousands

if not a million books per year, but would also lower

the cost of treatment per book.

Estimated processing costs for various mass deacidification techniques currently under development range from $2 to $6 per book. These estimates,

however, typically do not include the initial capital

investment costs (which can be quite substantial)

or the costs associated with handling large volumes

of books. Book handling will also present a variety

of technical and logistic problems that must be considered. Nevertheless, preservationists are looking

forward to the development of cost-effective mass

deacidification processes.

There are two mass deacidification systems in

operation in North America (one at Princeton

University and one at the Canadian National Library and Archives) and a few under development

(one of these is the Library of Congress’ system).

Some processes are also under development in

Europe.

The two operating systems use the non-aqueous

liquid solution developed by Wei T’o Associates.

Princeton University uses Wei T’o spray and has

developed a semi-automated system. Books are

Photo credit: Library of Congress

Wei T’o deacidification system used at the Canadian

National Library and National Archives.
6

treated one at a time in an exhaust hood. The pages

are turned manually while an automated spray

moves back and forth across the page. The system

treats about 1,000 books per year. The Canadians

are using a system developed by Wei T’o Associates. Ten to twenty books are placed in a chamber

which is then filled with the deacidifying solution.

The system was built as a pilot plant to test its feasibility; however, the National Library and National

Archives of Canada are now using it in production,

treating about 40,000 books per year. A process

developed by the Bibliotheque Nationale in France

is very similar to the Canadian system and began

operations during the fall of 1987.

The Library of Congress is developing a vapor

phase process which is the main subject of this report. A pilot plant capable of treating 300 books

at a time has been built. Tests on the system began

 in 1987. Another process under development is

I called the ‘Bookkeeper. Originally developed by

the Koppers Co., Inc., the process uses a dispersion to deposit ultra-fine alkaline particles. A pilotscale system has been designed and awaits demonstration. As this report was being written, another

firm proposed a new vapor phase process. OTA

has collected available information about all of the

processes and has evaluated their relative advantages and disadvantages.

Combined Strengthening/Deacidification

Deacidification techniques are effective for books

and paper that are not yet brittle. They cannot, however, restore lost durability. An ideal tool for the

preservationist is a process that both deacidifies and

strengthens books en masse. It would be very desirable to combine the deacidification processes under

development with the strengthening techniques that

are also being developed. Such techniques are under development in Europe.

One combined strengthening/deacidification

process is operating (at a very small scale) and two

are under development. The Austrian National Library has a small-scale system to treat its newspaper

collection using an aqueous process with calcium

hydroxide for deacidification and methyl cellulose

for strengthening. The German Library in Leipzig is developing a different strengthening process

using this same aqueous deacidification chemistry.

Strengthening will be accomplished by depositing

a new layer of paper composed of cotton cellulose

fibers. The British Library has begun development

of a polymerization process for strengthening. Depending on the chemical used, the process could

also be used to deacidify. None of these combined

processes have been developed far enough to be considered for mass book preservation in the near

future.

FINDINGS

The Library Process and Program

The Library of Congress has recognized the

problem of acid deterioration of books and other

paper materials for a long time. The Library staff

have invested considerable effort in the investigation of deacidification processes and have selected

the DEZ process as the one that meets their needs.

Selection of the DEZ process by the Library of Congress has followed a logical procedure comparing

alternatives on the basis of criteria established by

the Library for its collection. Since the late 1970s

decision to pursue the diethylzinc (DEZ) process,

most of the Library’s effort has been devoted to

perfecting this process and solving the engineering, safety, and other problems associated with the

chemical treatment plant.

The Library of Congress has built a second DEZ

pilot plant and has begun a series of engineering

and process effectiveness experiments as of this writing. The Library staff have done early planning

but have not made firm decisions yet about the

management, design, construction, and operation

of a full-scale facility. A total system including book

selection, handling, and transportation is planned,

but has yet to be designed. Final plans for contracting and management of the full-scale plant also are

needed. The Library of Congress needs to consider

important details of project planning and manage-
7

ment soon in order to more accurately predict

costs, capacity, and operational results of this major undertaking.

Technological Effectiveness

The DEZ process developed by the Library of

Congress extends the life remaining in the paper

at the time it is treated. The Library claims that

the process will extend the life of acid book paper

three to five times its life if left untreated. These

claims are based on fold endurance tests that have

been made on a variety of test papers. But it is not

clear how long the life of an actual book in the

Library’s collection will be extended.

The Library intends, as part of its current pilotplant tests, to analyze the overall benefits to all

books to be expected with DEZ treatment. The results of those tests are needed to quantitatively

project the benefits of the entire program. Some

scientists would also urge more tests on older papers

typical of the Library’s collection.

Safety

DEZ is a hazardous substance that must be handled carefully and in accordance with strict safety

procedures. DEZ will spontaneously ignite if exposed to air. Fire is the principal hazard, and there

is a remote chance of explosion. However, DEZ

has been used safely for other purposes. There is

no unusual fire hazard, however, once the books

are treated.

The early engineering development of the DEZ

process by the Library and NASA Goddard resulted in an accident caused by inadequate management of engineering and safety procedures.

Careful attention to safety and good chemical process engineering standards have been followed with

the design, construction, and plans for operation

of a second pilot plant with Texas Alkyls in Houston. OTA finds these initial efforts adequate, but

pilot plant tests now underway are needed to demonstrate all safety aspects. As of this writing a series

of engineering experiments is underway at the

Houston pilot plant.

The fill-scale plant, if built, will need equal or

greater engineering attention, especially related

to safety standards and practices during operations. Scale-up design will encounter additional

engineering problems. Safety practices must be developed for a new site, new plant management, new

operators, and a new community setting.

cost

To accurately and completely define costs, capacity, and operations for a full-scale DEZ facility, some basic decisions and plans remain to be

made. These plans include a total system design,

including not only the full-scale DEZ facility but

also the procedures for book selection, handling and

transportation, and final plans for contracting and

management.

For the purpose of this OTA study, the Library

of Congress estimated the capital cost of the fullscale DEZ deacidification facility at $4.9 million

without a contingency and the annual operating

costs for a capacity of 1 million books per year at

$1.8 million. These costs do not include a number

of items that have not yet been detailed enough to

make estimates (e. g., book transportation) or are

not considered now by the Library to be applicable (e. g., engineering development at the pilot

plant). OTA considers that actual costs could vary

considerably from these estimates once the important engineering and planning decisions listed

above have been made. OTA also believes it useful to add rough estimates of the missing items and

contingencies for unknown factors and thus arrive

at a more inclusive budgetary estimate.

The most critical factor in per-book costs is the

capacity of the final plant. The vacuum chamber

cycle time has a major influence on capacity as do

transportation and book handling factors. These

latter parts of the system need to be defined. Costs

for transportation and handling are also very rough

at this time. OTA has attempted to factor in these

uncertainties to arrive at its own estimate, OTA

has also used a +/-20 percent range of numbers because of the uncertainty of these costs. OTA’s resulting per book cost estimate is from $3.50 to $5.00
8

including amortization and interest on capital assuming a 1 million books per year plant capacity.

Alternative Processes

Although the problem of deteriorating paper has

been known for almost 100 years, only one mass

deacidification plant has been operating anywhere

for any length of time. The Wei T’o process has

been used by the National Archives of Canada for

the past 7 years at a capacity of about 40,000 books

per year. There are no deacidification facilities that

can handle the large number of books (over 1 million books per year) envisioned for the Library facility. Other systems are in operation at a much

smaller scale, are designed for a pilot plant scale,

or are only ready for testing on a pilot plant scale.

Of those processes for which OTA had sufficient

data, two of them, Bookkeeper and Wei T’o, merit

some consideration as alternatives to DEZ.

In general, the effectiveness of deacidification

processes has not been unambiguously established.

OTA has found no independent tests and evaluations of the Wei T’o and Bookkeeper processes

data on treatment results have been developed by

the firm or organization that is promoting the process. This is also true of the Library of Congress.

(However, the Library of Congress’ Laboratory is

highly regarded as a leader in the field and tests

of DEZ treatment effectiveness are far more extensive than those conducted on the alternative processes. ) Without some independent tests with standard procedures, comparisons of the final results

of alternative processes will always be uncertain.

By comparison to Bookkeeper and Wei-T’o on

a pilot plant scale (50 to 150 books per day), the

Library of Congress’ pilot plant at Texas Alkyls

appears to be considerably more expensive. Whether

the cost difference would be significant for a larger

scale cannot be determined without further pilot

plant tests (not yet done at all for Bookkeeper) and

complete design for the large-scale plant.

ORGANIZATION OF THIS REPORT

The remainder of this report is presented in two

parts. Part I addresses the Library of Congress’ program for mass deacidification of books and other

library materials. It analyzes the work completed

to date and the specific plans to build and operate

a large-scale chemical treatment plant over the next

few decades. That plant is expected to deacidify over

1 million books per year.

Part II addresses possible alternatives to the proposed Library of Congress’ deacidification system

and other issues related to the value of deacidification and the costs and results of other approaches.

This part includes discussions of acid-free paper production; the effectiveness and costs of competing

processes; and an evaluation of chemical treatment

results to be expected.
Part I

The Library of Congress’

Mass Deacidification Program
Chapter 1

Overview
CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Library of Congress’ Problem and Strategy . . .

Status of the Deacidification Program . . . . . . . .

Process Development. . . . .

Quality Control . . . . . . . . .

Book Handling.. . . . . . . . .

Health and Environmental

Funding . . . . . . . . . . . . . . . .

Discussion

Figutw No.

1.

2.

3.

4.

Library

Library

Library

Library

. . . . . . . . . . .

ofCongress

ofCongress

ofCongress

● ☛☛✎ ✎

. . . . . . . . . . . . . . . .

. . . . . . . +.*....* .

Assessment . . . . .

Figures

General and Law Collections

General and Law Collections

General and Law Collections

Survey

Survey

Survey

of Paper Strength.

of Paper Acidity . .

of Ligninin Paper

of Congress, Mass Deacidification Program: Current Scheduleof

Major Tasks, January 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table

T&leNo.

1. Library ofCongress Collections on Paper As of Sept. 30, 1986 . . . . . . . . . . . .

Page

13

13

15

15

16

17

18

18

18

Page

. . 14

,. 14

. . 15

. . 16

Page

. . 14
Chapter 1

Overview

INTRODUCTION

Libraries around the world are faced with a serious preservation problem but it is of huge proportions at the Library of Congress. The Library

houses over 66 million items, including 14 million

books. It is estimated that 25 percent of these books

are brittle and another 1 to 2 million are at risk

of becoming brittle over the next 20 years. As a

major part of the their overall preservation effort,

the Library initiated a program aimed at deacidify -

ing books en masse. Much of that program has been

devoted to the development of a process capable

of treating between 500,000 to 1.5 million books

per year. The process is unique and has many advantages over more traditional techniques. However, there have been questions raised about the

process’ effectiveness, safety, and costs,

Part I of this study will evaluate the Library of

Congress’ mass deacidification program and the isLIBRARY OF CONGRESS’

The Library of Congress’ holdings of over 66

million items ranges from books to maps to musical scores. Books comprise the single largest holding. The Law collection and the General collection

contain almost 14 million volumes, and receive over

350,000 additional books each year. In addition to

books, the Library holds over 1 million technical

reports, 35 million pages of manuscripts, over 3 million sheets of music, and nearly 4 million maps (see

table 1). All of these items are at risk of becoming

brittle and most are potential candidates for

treatment.

In January 1984, the Library sampled the books

in their Law and General Book collections to determine how many books were already brittle and

how many had high acid content and, therefore,

were at risk of becoming brittle. 1 Based on this sam1 The Desicgn and Analjsis of a Sample of the Condition of Books

in the I.ibrary of Congress, a Report prepared for the Librar}~ of Congress by King Research, Inc., Mar. 28, 1984.

Photo credit: Library of Congress

Brittle book from the Library of Congress’

collection.

sues of effectiveness, safety, and cost in an effort

to assist Congress with its decision about authorizing this program to proceed.

PROBLEM AND STRATEGY

pie, the Library estimated that 25 percent of their

collection, over 3 million volumes, had already become too brittle to permit circulation (see figure

1). The pages of these books cracked when folded.

Another 45 percent of the books were categorized

as weak (i. e., their pages on the average could not

withstand 50 folds). Of the collection, 97 percent

are acidic (a pH value less than 7. O), and, therefore at risk of becoming brittle (see figure 2).

Roughly 50 percent of the collection is made with

paper containing lignin (see figure 3). Lignin is a

highly unstable constituent of wood pulp and leads

to rapid deterioration of paper. The Library estimates that each year over 77,000 additional books

become too brittle to circulate.2 It should also be

noted that the median age of the books in this collection is 25 years.

2’ ‘Congress Considers ‘Brittle Books’, ” Publisher’s W’eek)},, hiarch

1987, p. 13.

13
14

r

I

1

I

(

,

(

I

Table l.— Library of Congress Coiiections on Paper As of Sept. 30, 1986

(numbers rounded to nearest thousand)

Collection Volumes Sheets

DEZ treatment expected . . . . . Regular books . . . . . . . . . . . . . . 14,046,000

DEZ treatment planned . . . . . . Manuscripts. . . . . . . . . . . . . . . . 35,522,000

Maps 3,862,000’

Sheet music . . . . . . . . . . . . . . . 3,699,000

DEZ treatment considered . . .Other printed materials . . . . . . 6,647,000’

Technical reports . . . . . . . . . . . 1,414,000

Art books . . . . . . . . . . . . . . . . . . 348,000

Music manuscripts. . . . . . . . . . 319,000

Prints and drawings . . . . . . . . . 257,000

Pamphlets . . . . . . . . . . . . . . . . . 179,000C

Popular applied graphic arts. . 95,000

Posters . . . . . . . . . . . . . . . . . . . . 61,000

No DEZ treatment. . . . . . . . . . . Rare books. . . . . . . . . . . . . . . . . 594,000

Fine prints . . . . . . . . . . . . . . . . . 95,000b

Bound newspapers. . . . . . . . . . 40,000

%cludes some volumes.

blncludes some pofffolios.

cMostly booklets.

SOURCE: Library of Congress

Figure 1 .—Library of Congress General and Law

Collections Survey of Paper Strength

ak to moderate stren Strong -

11%

o-1 1-3 3-1o 10-50 50-300 Over 300

Paper strength (MIT folds)

Variation of strength of book paper

SOURCE: Library of Congress, January 19&.

In an effort to preserve their collection, the Library operates a comprehensive preservation program which includes rare book and document

conservation, extensive environmental control,

microfilming, book binding, and new optical disk

formatting. Microfilming represents a major part

of the preservation effort devoted to transferring

information from brittle materials. Besides maintaining the newspaper collection on microfilm, the

Figure 2.—Library of Congress General and Law

Collections Survey of Paper Acidity

10L2%

o

24%

11%

6%

3%

<3.0 3.0-3.9 4.0-4.9 5.0-5.8 5.9-6.7 7.0 & >

pH value

Variation of acidity of book paper

SOURCE: Library of Congress, January 19&,

Library also microfilms between 10,000 and 20,000

brittle monographs and serials per year at a cost

of about $40 per volume. It is the largest microfilming operation in the world. Even so, they cannot

keep up with the number of books that are deteriorating. With 3 million books already brittle and

70,000 additional books becoming brittle each year,

the Library’s stacks will hold about a 200-year backlog of brittle books by the year 2000.
15

Figure 3.—Library of Congress General and Law

Collections Survey of Lignin in

Percent of books

Paper

-ii h

.8 %7

Variation of Iignin content in book paper

SOURCE: Library of Congress, January 1984.

To slow down the embrittlement of acidic books,

the Library decided to develop a mass deacidification process that would run in parallel with the

microfilming program. It is important to note that

deacidification is not an alternative to microfilming but a complimentary treatment that delays the

need to transfer information to a new media. Deacidification by itself, i.e., without parallel strengthening, cannot help the 3 million books that are already brittle.

The basic strategy of the deacidification program

is to treat all new acquisitions entering the collection first, before putting them into the stacks. In

addition, books already in the collection would be

selectively deacidified over time. The Library set

a goal of deacidifying their entire book collection

in 20 years.

The rationale for treating the incoming books

first is that it should increase the cost-effectiveness

of the program. Deacidification is generally believed

to extend the life of a book by two to five times.

Therefore, if paper in a new book has 50 years of

useful life remaining, deacidification can extend this

to 100 to 250 years. If paper in an old book has

only 5 years of life remaining, deacidification will

only extend its life 10 to 25 years.

The Library also wants to be able to treat other

formats, and has expressed intentions of experimenting with adding a strengthening step to the

process.

STATUS OF THE DEACIDIFICATION PROGRAM

The Library began its mass deacidification program in 1973. The program now consists of four

basic subprograms:

● the development of the plant engineering and

large-scale facility for the mass deacidification

process;

● the development of an appropriate quality control program;

● the development of a book handling management program; and

. an assessment of the health and environmen t~

impacts.

A master schedule for the program is shown in

figure 4.

Process Development

Most of the effort to date has focused on process

development. Beginning in 1973, the Library’s

chemists explored various ideas in mass deacidification and invented a unique process utilizing

diethylzinc (DEZ) vapors. Numerous laboratory

and large-scale tests have been conducted to verify and develop the process. Currently, a pilot-scale

system (capable of treating 300 books at a time) has

been designed and constructed at Texas Alkyls, outside Houston. Texas Alkyls is the principal manufacturer of DEZ in the United States and has been

working with the Library since the beginning of

its program.
16

I

I

t

!

Figure 4.-Library of Congress, Mase Deacidification Program:

Current Schedule of Major Tasks, January 1988

Calendaryear

SOURCE: Office of Technology Aesesement, 19SS; based on information received from Library of Congreee

This is actually the second pilot plant that has

been built by the Library. The first was designed,

built, and operated by Northrup Services, Inc., on

site at NASA’s Goddard Flight Center in Greenbelt, Maryland. This plant was demolished in 1986

after two fires and an explosion rendered it inoperable. DEZ is pyrophoric, i.e., it will spontaneously

ignite in air. Therefore, fire is a hazard that must

be safely managed. This issue will be more fully

discussed in chapter 5.

Construction of the Texas Alkyls pilot plant was

completed in October 1987. The first tests of the

plant began in December 1987.

The Library has contracted with Texas Alkyls

to run 10 to 15 tests during 1988. These tests will

evaluate the system’s operability, effectiveness of

treatment, safety, and economics. They will also

be used to optimize the process parameters, cycle

times, and final design (including plant capacity),

for a full-scale system.

The full-scale plant is scheduled to begin construction in 1989 and to begin operation in 1990-

91. The plans for who will design, construct, manage, and operate the plant have not yet been determined. The option that has received the most

attention is to locate the plant at Fort Detrick in

Frederick, Maryland. Under this option, the U.S.

Army Corps of Engineers would contract for the

design and manage the construction of the plant.

The Library has stated its interest in contracting

the management and operation of the plant to a

private chemical company that has had experience

in handling materials such as diethylzinc.

Quality Control

A quality control program is being designed to

ensure that the effectiveness of the process is maintained. As of January 1, 1988, test criteria had been
17

proposed that include accelerated aging/fold endurance tests and analysis of the following major

factors:

●

●

●

●

●

●

●

completeness of deacidification,

average percent zinc oxide deposited,

uniformity of zinc oxide deposited,

cover stains,

text block rings,

odor, and

other.

Tests at the Texas Alkyls pilot plant are planned

to provide information so that a statistically validated quality assurance program can be developed.

The most important issue that will be addressed

is the evaluation of test books as surrogates for actual books in the Library’s collection. This evaluation will include data on suitability of various test

papers, correlation of test book characteristics with

regular books, and determination of a doseresponse curve for test papers and its correlation

with regular books. If test books do not provide a

suitable surrogate for actual books, then an alternative approach will be necessary. A consultant to

the Library has suggested using purchased used

books to represent books already in the Library collection and extra copies of new books that are to

be treated.

Another issue that will be addressed is the appropriate number, format, and placement in chamber of test books.

The pilot plant tests to develop a quality control

program will also provide a large reservoir of treated

books of known characteristics and composition for

research purposes; and data to correlate new test

paper behavior with that of papers previously used

but now unavailable.

Book Handling

Book handling and its management represents

a major part of the deacidification program. This

part of the program has been divided into three integrated projects:

● the movement of books between the Library

and the treatment facility,

● the procedures for returning treated books to

circulation at the Library, and

. coordination with other preservation programs.

Photo credit: Library of Congress

First prototype of book handling carts

for DEZ treatment.

The movement of books involves both logistics

and design. The Library has experience in moving tens of thousands of books each year, but not

a million books each year. Loading docks must be

redesigned, and equipment including fork lifts,

carts, etc., must be designed to operate in relatively

confined spaces. The obsolete loading dock at the

Jefferson Building has been redesigned by an outside consultant and construction work is to begin

in 1989. The Library has also contracted with an

outside firm to study the design of book-handling

equipment and logistics.

The procedure for returning treated books to circulation basically requires some form of identification that the book has been deacidified. Logistics and the design of that identification system are

considered very important by Library and preservation specialists. These topics will be addressed

by the aforementioned study.

The Library has three ongoing preservation

activities that also involve pulling books from the

stacks for treatment of some kind. In addition to

microfilming, the Library has relabeling and rebinding programs. Currently, these programs are

not coordinated and books are selected independently from the collection. However, these programs

will have to be coordinated with the mass deacidifi-
18

I

I

I

I

cation program to ensure an efficient operation.

The coordination between microfilming and deacidification is the most problematic. Deacidifying

a brittle book is not cost-effective. However, the

number of brittle books that would be pulled from

the shelves would quickly overwhelm the microfilming capability of the Library. The costs associated

with storing and managing a separate inventory of

brittle books while they await processing may be

prohibitive. The Library staff is still discussing this

issue.

Book handling is a critical factor in any largescale deacidification program. It may actually limit

the eventual capacity of the deacidification system

and, although only rough estimates have been

made, OTA believes it could represent a major

operating cost.

Health and Environmental Assessment

The Library has completed some limited laboratory toxicology studies and extensive literature

studies on the health effects of treated books on library workers and users. The major change imparted to books during the treatment is the deposition of zinc oxide in the paper. In general, zinc

oxide is considered a benign substance. However,

the effects of exposing the skin to treated papers

or ingesting treated papers orally were examined

on mice and rabbits. No adverse effects were identified. The Library has also designed an extensive

animal study to examine the effects, including carcinogenic effects, of chronic inhalation of the dust

that may be associated with the process or the

treated paper. The study was begun in 1987 and

will take at least 2 to 3 years to complete.

The Library also intends to assess the environmental impact of the full- scale plant. The Library

did make an earlier preliminary assessment, during the design of the first pilot plant, but this must

be redone to take into account the new design. Who

will perform the new assessment, and in what detail, will be determined after the design and operations planning for the full-scale plant is completed.

Funding

The Mass Deacidification Program is a line item

in the Library’s budget. Since the beginning of the

program in 1973, the Library has spent $4.5 million on process development. Design, construction,

and testing at the Texas Alkyls pilot plant has cost

$2.8 million. Additional funds have been spent on

designing and planning for the book handling

management. The animal study will cost about $1.5

million.

The Library, at the request of OTA, has estimated the capital and operating costs for the fullscale plant assuming it will be placed at Fort

Detrick. These costs were estimated (by Library

engineers working in conjunction with the pilot

plant design team and architects working on the

full-scale design) at $4.9 million to build and $1.8

million per year to operate at a capacity of 1 million books per year. OTA added a rough estimate

of certain costs not included in the above figures

and concluded that total capital costs may be $11.1

million for the facility and total annual operating

costs may be $2.8 million.

DISCUSSION

The Library of Congress has recognized the

problem of acid deterioration of books and other

paper materials for a long time. It has invested considerable effort in the investigation of deacidification processes and has selected one process that best

suits its objectives.

The Library’s strategy is to deacidify all new

books as they enter the Library (about 350,000 per

year). In addition, the Library plans to treat the

rest of its book collection over a 20-year period.

Deacidifying old books, without strengthening, may

not be as cost-effective as doing both—i.e., deacidification and strengthening. The Library intends

to incorporate strengthening into its program at

some future time, but has not yet selected an approach to do so.

Selection of the DEZ process by the Library has

followed a logical laboratory routine in comparing
19

alternatives on the basis of criteria established by

the Library for its collection. However, since a decision to pursue the diethyl zinc (DEZ) process in

the late 1970s, the Library has directed very little

effort toward supporting the development or testing

of other alternatives. The Library has investigated

and kept informed of other paper preservation work

in the United States and abroad, however, most

of its effort has been devoted to perfecting the DEZ

treatment process and solving the engineering,

plant safety, and other problems associated with

the DEZ chemical treatment plant.

ing and process effectiveness experiments as of this

writing. It has done early planning but has not yet

made firm decisions about the management, design,

construction, and operation of a full-scale facility.

A total system design would include book selection,

handling and transportation, and procedures for

contracting and management of the full-scale plant.

The Library of Congress needs to consider important details of project planning and management

soon in order to more accurately determine costs,

capacity, and operational results of this major undertaking.

The Library of Congress has built its second

DEZ pilot plant and has begun a series of engineer-
Chapter 2

The DEZ Process and Its

Development
CONTENTS

Introduction . . . . . . . . . . . . . . . . . +

The DEZ Process . . . . . . . . . . . . .

General Description. . . . . . . . . .

Process Control . . . . . . . . . . . . .

Cycle Times... . . . . . . . . . . . . .

Hardware . . . . . . . . . . . . . . . . . .

Development History of the DEZ

Objectives . . . . . ... ... .....O O

Selection of DEZ. . . . . . . . . . . .

Process Chemistry . . . . . . . . . . .

Development History . . . . . . . .

Discussion

Figure No.

. .

5.

6.

7.

Key Steps

Sifiplified

Evolution

. . . . . . . . . . . . . . . . . .

Process

Page

23

23

23

24

25

26

27

27

27

28

29

33

in the DEZ Treatment Process . . . . .

DEZ Process Flow Diagram ....,...

of DEZ . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .**..+* 24

,.,... . . . . . . . . . . . . . . . . . . . . . 26

. . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Z. Compounds Tested by the Library’s Laboratory

1970-74. . . . . . . . . . . .....**.*.....***..*.. . .

for Deacidification of

. . . . . . . . . . . . . . . ..**

Paper,

. . . . . .

Page

.0 28
Chapter 2

The DEZ Process and Its Development

INTRODUCTION

This chapter briefly describes the DEZ process ducting its evaluation in the middle of ongoing

and its evolution. OTA finds that the evolution has development efforts and there are a number of engifollowed a reasonable path from laboratory to pi- neering issues that remain to be solved, including

lot plant demonstration. However, OTA is con- how the Library will scale-up to a full-scale facility.

THE DEZ PROCESS

General Description

The mass deacidification process that the Library

has been developing uses DEZ vapors to treat

books. DEZ belongs to a class of compounds called

metal alkyls or organo-metallics. Metal alkyls, in

general, and DEZ in particular, will react very

quickly with free hydrogen ions. Therefore, acids,

being generous donors of free hydrogen ions, will

react very quickly with DEZ. Deacidiflcation occurs as DEZ vapors permeate the books and react

with all acids in the paper converting them to zinc

salts.

DEZ vapors also react with water in the paper

to form zinc oxide. The zinc oxide acts as an alkaline buffer that can neutralize any acids that may

form after treatment. The amount of zinc oxide that

gets deposited depends in a large part on the

amount of water in the books. It also depends on

the amount of the DEZ used, time or rate of exposure, and particular permeability of the paper.

The process basically consists of three steps; dehydration, permeation, and dehydration. Dehydration reduces the amount of water in the books to

some predetermined amount based on the amount

of zinc oxide that is desired. Permeation exposes

the books to the DEZ vapors. Dehydration soaks

the books in water vapor to restore moisture to the

books. An optional step during dehydration is to

soak the books in moist carbon dioxide. This option will be discussed more fully later in this

chapter.

Metal alkyls are pyrophoric, meaning they will

spontaneously ignite if they come in contact with

air. Therefore, the book treatment process must

take place in an air-free environment within a

vacuum chamber. The Library process uses DEZ

as a gas only at very low pressure within the

vacuum chamber.

The following is a general description of the process as it has evolved to date:

Books are placed in a processing chamber. The

air in the chamber is removed through a vacuum

pump, lowering the pressure inside the chamber.

The chamber is kept at a low pressure while the

books are heated. Water migrates out of the books

and evaporates. The evaporated water is removed

through the vacuum pump. The amount of water

removed is monitored indirectly by measuring book

temperatures (see figure 5a).

Once the desired amount of water has been removed, the chamber is purged with nitrogen gas

to ensure that no air remains in the chamber (see

figure 5b).

After the chamber is purged, DEZ vapors are

introduced into the chamber. DEZ vapors react

with the acids and water in the books generating

both heat and ethane gas. Exposure to the DEZ

vapors continues until no more heat or ethane are

evolved or until the desired amount of zinc oxide

has been deposited. The amount of zinc oxide that

has been deposited can be monitored indirectly by

measuring book temperatures (see figure 5c).

Ethane gas and unreacted DEZ vapors are removed from the chamber. The unreacted DEZ is

condensed and recycled. The ethane is vented to

the atmosphere (see figure 5d).

When the permeation step has been completed,

the chamber is again purged with nitrogen gas to

ensure that all of the ethane and unreacted DEZ

is removed (see figure 5e).

After the chamber is purged, water vapor (or

moist carbon dioxide) is introduced into the cham23
24

Figure 5.—Key Steps in the DEZ Treatment Process

Books

(a)

(c)

\ /

(e)

SOURCE: Office of Technology Assessment, 1988.

ber. The books are allowed to soak in the water

vapor until much of their original moisture content is restored. The amount of moisture taken in

by the books is estimated by monitoring water introduced (see figure 5f.

When the desired amount of moisture has been

restored, the chamber is vented to the atmosphere

and opened and the books removed.

Process Control

Physical and chemical events during processing

with DEZ occur over a relatively wide range of temperatures and pressures. Therefore, fine control of

(b)

(d)

(f)

these parameters is not needed except to optimize

the process. However, there are a few critical temperatures and pressures that do impose limits on

the process. Thus the temperatures and pressures

must be accurately monitored and measures must

be incorporated to control them.

During dehydration, the books will lose heat.

The book temperature must be controlled to prevent them from freezing and to keep cycle time

short. Also during dehydration, it is undesirable

for the water vapor in the chamber to condense,

therefore, the interior surfaces in the chamber must

be kept above the dew point temperature of water.
25

If the water does condense and remains in the

chamber as a liquid it will react with the DEZ

vapors during permeation and will foul the chamber with excess zinc oxide and will waste DEZ, If

liquid DEZ should somehow enter the chamber

during permeation and there is liquid water present,

there will be a vigorous reaction, generating excess

ethane and heat which will quickly raise the pressure and temperature inside the chamber. A pressure relief valve is fitted in case maximum pressure limits are exceeded.

During permeation, the DEZ reactions with the

acids and water will generate heat. The book temperature will rise. Paper begins to degrade at 1000

C, and other book materials may be damaged. At

1500 C, the degradation can be very rapid. Therefore, temperatures inside the chamber are kept well

below 1000 C. At the same time, however, it is undesirable for either the DEZ vapors or the ethane

gas to condense inside the chamber. Therefore, the

temperature of the internal surfaces within the

chamber must be kept above both dew points.

The most critical constraint in the process is the

stability of DEZ. DEZ begins to decompose at 1200

C. At 1500 C the decomposition will become selfsustaining and uncontrollable. Therefore, temperatures throughout the system, including the chamber, are kept below 800 C. The present system design goal is to keep book temperatures at 600 C or

below. Ongoing pilot plant tests will confirm

whether this goal is feasible.

Dehydration also generates heat, about as much

and as rapidly as does permeation.

Temperature control in various pieces of hardware is maintained by circulating heated or cooled

oil. The book temperature is controlled by introducing heated or cooled inert gas.

Besides monitoring and/or controlling temperature, pressure, and book weight, an accurate inventory of DEZ is maintained. The total amount

of DEZ at the start of the cycle must be accounted

for at the end of the cycle. All DEZ holding vessels

are weighed. The difference in weight before and

after treatment must be balanced by the amount

of DEZ that was reacted in the books. The latter

amount can be determined by the weight gain in

the books during permeation. Pilot plant tests will

confirm whether this measurement or some other

means of monitoring is feasible. The importance

of maintaining an accurate DEZ inventory will be

evident in the discussion of the first pilot plant’s

accident, in chapter 5.

In general, the process is relatively straightforward, but it does involve a complex sequence of

operations. It also requires extensive monitoring

to ensure safe and efficient operation. A computerized distributive control system (DCS) has been incorporated to assist the operator in monitoring,

managing, and controlling the system.

The computer continuously monitors pressures,

temperatures, flow rates, etc. throughout the system. In addition, it continuously monitors the status of all valves (e. g., open/closed) and pieces of

equipment (e. g,, on/off). Before the initiation of

any action, the computer checks these parameters

against a set of predetermined values, called ‘‘permissive , that are programmed for that stage of

the process. Any action, whether initiated by the

operator or the computer, cannot be performed if

these permissive are not satisfied. If the permissive are breached during operation, or in the case

of an emergency, the computer is programmed to

safely halt or shut down the process. The interaction between the human operator and the computer

is critical for the safe operation of the plant and will

be discussed further in chapter 5.

Cycle Times

Current estimates of the cycle time for a full-scale

operation range from 45 to 55 hours. The cycle time

is limited mainly by the rate at which books can

be dehydrated. Depending on how the books are

stacked in the chamber, the larger the number of

books being treated, the longer it takes for books

in the interior of the stack to give up their water.

Dehydration times can be affected by the rate the

water vapor is pumped out of the chamber. Pumping too fast, however, will lower the book temperature too fast. As of this writing, estimated dehydration times for a full-scale operation would range

from 25 to 30 hours. Permeation, in a full-scale

operation, would take from 6 to 9 hours and dehydration 7 to 8 hours. Other steps as well as loading and unloading books would bring total cycle

time to 45 to 55 hours.

83-356 0 - 88 - ? : OL 3
1

I

Figure 6.-Simpltfied DEZ Process Flow Diagram

Vent

Condenser (

DEZ

vaporizer

f

— DEZ receiver

storage (liquid)

(liquid)

SOURCE: Office of Technology Assessment, 19%0

Hardware

-

-

recycle

pump

The hardware and capital investment required

for the Library plant is large. Because of the hazardous nature of DEZ, the need to locate in an area

zoned for chemical operations, and the lack of available space near the Library of Congress, a separate facility away from the Library would have to

be built. A simplified flow diagram is shown in figure 6. The system would consist of the following

subsystems:

. processing chamber or chambers;

● a vacuum system;

. a DEZ handling system that would nominally

include liquid DEZ containers, a DEZ

vaporizer, condenser(s), pump, and sealpots;

Temperature Vent

control

system

I

Vacuum

1 pump

pump

. a nitrogen gas system;

. a water vapor system; and

. a heat exchanger system used for temperature

control.

As mentioned, the operation of the system will be

managed by a computerized distributive control

system.

Capital costs are discussed more fully in chapter 4, A detailed design of the full-scale plant has

not yet been started but the general approach would

be to scale-up from the pilot plant making any

modifications that appear warranted after completing pilot plant tests. The book treatment capacity

of the pilot plant is about l/25th the scale envisaged

for the full-scale plant.
27

DEVELOPMENT HISTORY OF THE DEZ PROCESS

Objectives

Since its beginning in 1973 the objective of the

mass deacidification development program has been

to develop a process that would:

●

●

●

●

●

process large numbers of books and other formats, capable of treating the entire book collection in 20 years;

require no preelection (i. e., be compatible

with all other book materials, inks, pigments,

etc. and cause no visual or tangible differences

in the treated material);

prolong the life of the book as much as possible (i.e., permanently and completely neutralize all acids and deposit a sufficient permanent

and uniform alkaline buffer);

be cost-effective; and

be safe.

Selection of DEZ

Based on the above goals, the Library decided

to pursue the development of a vapor phase process as opposed to a liquid phase process. The

Library’s chemists felt that large numbers of books

could be more quickly and uniformly treated by

vapor reactants diffusing around and through the

books. Also, the liquid phase processes in use required pretesting to ensure that the materials to be

treated were compatible with the solvents used.

There were a few vapor phase deacidification

processes that had already been developed. A morpholine process was developed at the Barrows Laboratory, and two amine-based processes, one using

cyclohexylamine carbonate and one using ammonia, were developed in England and India, respectively.

The Library experimented with the morpholine

process. The principal limitation of this process is

its bad odors that cause headaches and nausea in

process workers. Other problems include an insufficient buffer, and questionable health effects. The

process had the potential of forming nitrosamines

which could be inhaled by workers. Morpholine can

also discolor paper.

The cyclohexylamine carbonate process was developed by Langwell in the early 1960s. The patents now reside with B.G. Robertson Laboratories,

London. Interleaf, Inc. is the sole distributor of the

product in the United States. This is basically a

manual process, but is so simple that it could be

used to treat a substantial number of books. Cyclohexylamine carbonate crystals are placed in a

packet in a book every 100 pages. Cyclohexylamine

is volatile and vapors containing the carbonate compound permeate through the book, reacting with

and neutralizing the acids. This process does not

leave an alkaline buffer, however, and the byproducts from the acid reactions are themselves

volatile. Under certain conditions, these byproducts

can revert back to the acid and give off an

ammonia-like odor. Also, at the time the Library

was investigating these various processes, the health

effects of cyclamates were a concern, raising questions about the health effects of cyclohexylamines

as well.

Kathpalia, also in the 1960s, developed an ammonia process. It suffers from many of the same

problems as the cyclohexylamine process, except

that the acid reaction byproducts are even more

volatile.

Unable to justify developing any of the existing

processes or chemicals, the Library began to search

for its own chemical and process. Table 2 is a list

of the compounds that were evaluated, To meet

their objectives, the chemical had to have a high

vapor pressure within the temperature limits of the

process (i. e., between O and 800 C), it had to react with all acids present in books, without forming any deleterious reactions with any of the other

book materials, the acid reaction byproducts had

to be stable, and an alkaline buffer had to be created to neutralize any acids that could form after

treatment.

Metal alkyls represented a class of compounds

that met these various requirements. Metal alkyls

are very reactive and will quickly neutralize all the

types of acids found in paper. In addition, either

directly or indirectly, the metal alkyls react with

moisture in the paper to form stable alkaline com-
28

I

I

Table 2.—Compounds Tested by the Library’s

Laboratory for Deacidification of Paper, 1970.74

1.

2.

3.

4.

: :

7.

8.

9.

10.

11.

12.

13.

14.

Triethyl aluminum

Diethylzinc

Ethylene imine cyclohexyl amine carbonate

Morpholine

Hexamethylene diamine formaldehyde

Calcium hydroxide and calcium bicarbonate

(Barrow two step)

Calcium chloride and ammonium carbonate

(double decomposition)

Borax

Methyl zinc carbonate

Magnesium acetonyl acetonate

Magnesium hexafluoroacetyl acetonate

Barium acetyl acetonate

Cyclohexyl amine carbonate (Langwell VPD)a

Silane deacidification agent (Dow Corning Z-6020)

15. Sodium carbonate and magnesium chloride

16. Magnesium methoxide and methyl magnesium

carbonate

17. Zinc ammonium carbonate

18. Ammonium zirconyl carbonate

%omDound used in the Interleaf process.

bcompound used in the Wei T’o Process.

SOURCE: Library of Congress.

pounds. The amount of stable alkaline compound

deposited depends on the amount of moisture in

the paper and can, therefore, be controlled.

The metal alkyls, however, were of concern regarding one major objective of the development

program—safety. Metal alkyls are pyrophoric. If

allowed to come in contact with air, they will spontaneously ignite. Furthermore, they react very

vigorously with water. Both reactions give off ethane which is flammable and potentially explosive

under certain conditions. The metal alkyl-water reaction that would deposit an alkaline buffer in a

book involves very small volumes of these reactants

and therefore is not a violent reaction. However,

it will generate heat and must be controlled.

Metal alkyls have been used for many years in

a variety of applications. Their major use today is

as an intermediate in the manufacturing of polyethylene and polypropylene. Fully aware of the hazards associated with metal alkyls, the Library felt

that these hazards were manageable and that the

advantages of the compounds were worth the costs

associated with developing a safe process.

Of the various metal alkyls tested, DEZ had the

highest vapor pressure in the temperature range involved. Initial tests indicated that papers exposed

to DEZ vapors were deacidified, had an alkaline

zinc oxide buffer deposited, and appeared not to

be adversely affected in any way. Based on these

conclusions, the Library proceeded to develop a

process around DEZ.

Process Chemistry

In the early stages of developing the DEZ process, the following reactions were thought to occur:

●

●

●

DEZ vapors react with both weak and strong

acids to form stable zinc salts and ethane gas.

DEZ vapors react with hydroxyl groups on the

cellulose molecule to form an unstable compound, ethylzincoxycellulose. During dehydration, this unstable compound would form zinc

oxide and ethane and return the cellulose to

its original form.

DEZ vapors react with aldehyde groups on the

cellulose molecule to form a stable alcohol and

ethane gas.

Originally, processing was based on eliminating

as much of the water as possible, and using the

hydroxyl reaction to form the alkaline buffer. It was

hypothesized that the amount of water in a book,

nominally 6 percent of the book’s weight, would

impede the permeation of DEZ into the center of

the book by immediately reacting with the DEZ on

the book’s outer edges. It was also thought that partial dehydration of the books during permeation

would leave a moisture gradient within the books

that would result in an undesirable gradient in the

amount of zinc oxide that would get deposited. The

hydroxyl group, however, could be expected to remain evenly distributed throughout the paper and

the books and result in a uniform distribution of

zinc oxide buffer.

Later experience indicated that this hydroxyl reaction must be slow and that most of the alkaline

buffer that gets deposited is the result of the water

reaction. A test that exposed very dry pure cellulose paper to DEZ vapors supports this observation. Therefore, the amount of alkaline buffer deposited in the books depends to a large extent on

the amount of water left in the book. It also depends on the amount of DEZ the books are exposed

to, possibly the rate and time of exposure, and the

particular properties (e. g., permeability) of the paper being treated.
29

After development had proceeded, the Library

chemists became aware of studies that indicated zinc

oxide could promote photodegradation of paper.

The Library conducted a few tests that showed

treated papers were more sensitive to photodegradation.1 Although photodegradation is not considered a serious problem at the Library, especially

in relation to acid deterioration and other degradation mechanisms, a solution to the problem was

sought. The solution sought by the Library was to

convert zinc oxide to zinc carbonate, which does

not promote photodegradation, by soaking the

books in carbon dioxide after dehydration. However, subsequent tests have shown that little if any

zinc carbonate forms after soaking the books in carbon dioxide. Whether the carbon dioxide soak is

useful and will remain as part of the treatment will

be determined in future tests.

‘George B, Kelly and John C. Williams, ‘‘Inhibition of Light Sensitivity of Papers Treated With Diethylzinc, presented at the Annual Meeting of the American Chemical Society, Washington, DC,

September 1979.

Development History

The evolution of the DEZ process is shown in

figure 7. The Library began bench-scale development in 1974. During these bench-scale tests, a

pressure cooker was used as a process chamber.

Sheets of test paper (or segments of books) were

placed in the cooker. Air was removed and the

books dehydrated. Dehydration continued until the

pressure in the cooker stabilized with the vacuum

pump turned off, indicating maximum dehydration. DEZ mixed in various concentrations with

hydrocarbons (e. g., octane) was injected into the

cooker as a liquid. The liquid sat at the bottom of

the chamber and evaporated. Vapors permeated

up through the paper of books, deacidifying the paper. Unreacted vapors were condensed at the top

of the cooker and the liquid recycled. Dehydration

was typically accomplished with nitrogen gas or alcohol saturated with water vapor which also neutralized any unreacted DEZ liquid remaining at the

bottom of the cooker.

Figure 7.- Evolution of DEZ Process

Lab Lab

tests tests

with DEZ With DEZ

solution / vapor

1973 75 77 79 81 83 85 87 89 91 1993

II II I I 1 1 1 J- 1 1 I I I I

Pressure G.E. NASA NASA NASA

cooker tests large scale small scale pilot

tests tests tests plant

Capacity 1 or 2 books

or

stack of

papers

DEZ Liquid DEZ

system mixture

with reflux

Vapor Vapor

Liquid DEZ Vapor DEZ DEZ DEZ

mixture mixture heat heat

incremental incremental continuous continuous

feed, no reflux feed with feed with feed with

recovery recovery recycle

Cycle 10 hrs 24-72 hrs 244 hrs 45 hrs ?

times

1 I 1 1

Texas

Alkyls

pilot plant

books

Vapor DEZ

heat

continuous

feed with

recycle

Est. 5(-90 hrs

Proposed

Fort Detrick

plant

?

Vapor DEZ

heat

continuous

feed with

recycle

?

SOURCE: Office of Technology Assessment, 1988
30

Photo credit Llbrary of Congress

Original pressure cooker test of DEZ at

Library of Congress

Typical dehydration times were about 5 hours.

Permeation times were about 5 hours.

The treated papers were evaluated for pH, zinc

oxide content, and brightness. Some of the papers’

fold endurances were also measured after accelerated aging. Typically, the results were positive, and

are discussed in more detail in the next chapter.

The goal of the program, to treat the entire book

collection in 20 years, required that the system had

to treat about 1 million books per year. If two sin-

+

I gle chambers were used, 7,500 books would have

to be treated in a single chamber. To test the feasibility of the process at this scale, a series of larger

scale tests were begun.

In 1979, the Library contracted with General

Electric’s (G. E.) Valley Forge Space Center to use

one of their large thermal/vacuum chambers, normally used for simulating space environments. The

tests treated 400 books at a time. The principal objective of these tests was to confirm the feasibility

of the process at this moderate scale. In addition,

a variety of processing conditions were evaluated,

including different ways of stacking the books in

the chamber.

The G.E. chamber that was used was 12 feet in

diameter and 26 feet long. Various processing hardware was fitted onto the chamber. The system was

essentially the same as that used in the Library.

A vacuum pump removed the air from the chamber. Liquid DEZ mixed with a hydrocarbon, Isopar E, was introduced into the chamber and allowed

to vaporize in the chamber (the last test used 100

percent DEZ, called neat DEZ). However, because

of the larger volumes of DEZ required to treat 400

books, it was introduced incrementally, as a precaution, to ensure that the amount of heat generated

would not raise the temperature above the limits

mentioned earlier. A separate pump was used to

remove the ethane and unreacted DEZ vapors.

These were removed into sample bottles. Unreacted

DEZ liquid at the bottom of the chamber was neutralized with alcohol.

A total of four tests were conducted. Complete

deacidification was achieved in two of the tests. Zinc

oxide contents ranged from 0.5 to 1.4 percent. It

was concluded that the best operating conditions

were long exposures at low pressures using 100 percent DEZ.

The best book-stacking configuration seemed to

be closed with the spine down. However, in each

of the tests, tide marks were observed on the covers. The tide marks were diffraction patterns caused

by excess zinc oxide. It was hypothesized that the

tide marks were caused by a thin film of DEZ

trapped between the books. Book covers generally

hold more water than the inside pages, providing

excess moisture for the excess DEZ to react with.

It was recommended that books be separated to allow good circulation of DEZ between the books.

Another observation was that moisture and small

air leaks into the system seemed to produce unwanted zinc oxide throughout the system, presenting a potential maintenance problem. It is also possible that small air leaks lead to the visible zinc oxide

surface deposition on books.

The test also demonstrated that relatively large

amounts of DEZ could be handled safely during

treatment. Further work would have to be done to

optimize the treatment, to reduce the amount of

cycle time, and to remove the tide marks from the

covers.

Encouraged by these results, the Library continued scaling up the process. In 1981, the Library

contracted with NASA’s Goddard Space Flight

Center to use one of their thermal/vacuum chambers to treat 5,000 books.
31

Although this was basically a feasibility test, a

substantial amount of engineering was done on the

various pieces of hardware. A large number of

safety reviews were conducted including a typical

NASA fault tree analysis. Also, 15 separate subsystem operating procedures were detailed. This

Photo credit: Library of Congress

Chamber used at NASA-Goddard for DEZ treatment

The size of the Goddard chamber was 10 feet in

single test, including planning, design, and construction, took 1 year.

Books were loaded in crates, separated by

diameter and 15 feet long. The system was basically the same as the one used at G.E. with one

major exception. DEZ, mixed with mineral oil, was

first fed into a vaporizer and introduced into the

chamber as a vapor. It was fed incrementally as

a precaution and to control temperature rises in the

books. The only temperature control for the books

was radiant heat from the chamber walls. The unreacted DEZ was condensed and recovered. Alcohol was still available should any liquid DEZ be

left in the chamber after permeation. Saturated carbon dioxide was introduced during dehydration to

test the conversion of zinc oxide to zinc carbonate.

In addition to the system instrumentation, individual books were also monitored for weight and

temperature to better track the process throughout

the stack of 5,000 books.

spacers, and marked by their location within the

chamber. Dehydration took 4 days (96 hours). The

books were exposed to DEZ incrementally for 6

days (124 hours). The books were dehydrated for

24 hours.

The results of the test were mixed. There were

three major problems.

First, treatment was not uniform throughout the

stack of books. Books at the bottom half of the

chamber were completely deacidified and had a

average zinc oxide content of 2.2 percent. Books

at the top levels of the chamber were hardly deacidified at all and had almost no zinc oxide deposited. Books in the middle of the stack were partially

deacidified; the outer portion of pages were deacidified, but at the center of the book the pages were

not deacidified. These middle books also had very

little zinc oxide (about 0.2 percent). These results

agreed with the data collected from the individual

books that were monitored during the process.

Photo cradit: Library of Congress

Books being prepared for NASA-Goddard test

of DEZ treatment
32

Books at the top showed little temperature rise. The

temperature of books in the middle rose near the

end of the process, and the books at the bottom

showed early increases in temperature. The evolution of ethane also indicated that most of the reactions occurred early in the process.

The cause of this first problem was judged to be

stratification of the DEZ vapors and the evolved

ethane. DEZ was introduced near the bottom of

the chamber. Ethane, being lighter, naturally rose

and sat at the top of the chamber. With only small

amounts of DEZ being injected at any one time,

the environment inside the chamber was basically

static. Ethane impeded the flow of DEZ vapors to

the upper books.

The second problem was that the zinc oxide was

deposited in rings. The concentration of zinc oxide in these rings was high on the outside rings and

diminished towards the center of the page. The

rings were blamed on the incremental pulsing of

the DEZ into the chamber. The hypothesis was that

as the permeation step proceeded, water continued

to migrate out to the edges of the books. With each

new pulse, more zinc oxide would be deposited on

the outside edges.

The third problem was that tide marks remained

on the covers, duplicating the patterns of the spacers

used to separate the books in the crates.

However, the tests were conducted safely at this

scale.

To solve the treatment problems the Library continued with a series of smaller scale tests at Goddard. A large diffusion pump housing was used as

the process chamber. Books were stacked in the test

chamber in two 50-book stacks.

Thirteen tests were conducted. The first test

duplicated the conditions and, thus, the problems

of the 5,000-book run. The rest of the tests were

aimed at solving the various problems. To correct

the ring problem, a continuous DEZ vapor feed (1

pound per hour (lb/hr)) and collection system was

developed. To correct for the stratification in the

chamber, DEZ gas was fed through the system at

a high rate to induce better mixing in the chamber. A variety of spacer designs and spacing dimensions were also tested.

Cycle times of these small-scale tests were reduced to about 45 hours. Complete deacidification

throughout the stack of books was achieved in a

number of these tests. Uniform zinc oxide was also

achieved. None of the spacer designs totally eliminated the tide marks. However, by minimizing the

contact between book and spacer the excess deposition of zinc oxide was reduced almost beyond detection.

Encouraged by the results of these small-scale

tests, the Library decided to build a pilot plant at

Goddard. This would be the first attempt at engineering a system for commercial feasibility. Northrup, NASA’s engineering contractor at Goddard

who designed and operated the 5,000-book and the

small-scale tests, was responsible for the design,

construction, and operation of the pilot plant. The

plant was built in an existing NASA building.

The system was designed to treat 300 books. Two

new continuous DEZ vaporizers were to be tested.

One would feed DEZ vapors into the chamber at

60 lb/hr, the other would feed it in at 200 lb/hr.

The DEZ vapors were to be condensed and recycled during the process.

Construction was completed in October 1985.

In December, during the final check of the system,

however, an accident occurred. A fire broke out

in the chamber. There were no injuries; property

damage to the building was minimal but somewhat

more extensive to the processing equipment. While

attempting to safely deactivate the system, an explosion occurred and another fire broke out. Again

there were no injuries, however, the system was

judged by NASA officials to be unsafe and an Army

demolition team was brought in to safely decommission the plant with small explosives.

A more detailed account of the incident will be

given in chapter 5. The information for this OTA

study was taken from the NASA Accident Investigation Report of September 4, 1986, as well as

OTA and NASA meetings and conversations during August-September 1987. However, the principal finding of the in-house accident review committee was that standard safety procedures and

practices were not followed in both the design and

operation of the the plant. The care and detailed

analysis that went into the test facilities were not

repeated in the pilot plant.
33

After the accident, the Library of Congress dis- The plant has been designed to treat about 300

continued its working arrangement with NASA. books. The chamber is 6 feet in diameter and 6 feet

However, using the experience gained in the fail- long. The process uses 100 percent DEZ. The DEZ

ure of the first pilot plant, and implementing all is continuously vaporized and introduced into the

of the recommendations made by the NASA acci- chamber at high flow rates. Unused DEZ gas and

dent review team, the Library has contracted for ethane is continuously pumped out of the chamand built a second pilot plant at Texas Alkyls’ site ber with the

outside Houston, Texas. Texas Alkyls has been the recycled and

Library’s principal supplier of DEZ and has over

20 years of experience in manufacturing and handling DEZ and other metal alkyls.

unused DEZ vapor condensed and

the ethane vented.

DISCUSSION

A number of tests have been planned for the new

pilot plant. In general these tests will provide engineering and operational information for the commercial plant, including maintenance needs, manpower requirements, reliability and safety of the

design and operations, and optimal temperature/pressure parameters for the various steps in

the process. Specifically, there are also four major

development issues that still need to be resolved.

These are optimizing the DEZ flow rate, optimizing book configuration, reducing cycle time, and

collecting scale-up engineering data.

The flow rate of DEZ into the chamber is very

critical for two reasons. First, it is important to

simultaneously expose as many books as possible

to the DEZ vapor. DEZ will start to react quickly

with the first books that it comes in contact with.

Therefore, if the DEZ is not uniformly distributed

at a high enough rate, deacidification will not occur in a reasonable exposure time.

The flow rate is also critical in ensuring that the

DEZ and the ethane that is evolved during permeation will be thoroughly mixed, prohibiting a

stratification of gases within the chamber.

The small-scale tests run at NASA after the

5,000-book run showed that a high DEZ flow rate

can eliminate the problem. A principal task during the pilot plant tests will be to duplicate these

results. The pilot facility is capable of generating

flow rates that would be equivalent to 10,000 lb/hr

in the full-scale plant, but it is doubtful that a flow

rate this high will be necessary.

Book configuration also plays a role in the circulation of vapors within the chamber. The principal issue involving book configuration, however,

is the spacing between books. Spacing between

books plays a critical role in preventing the excess

zinc oxide coating from depositing on book covers. The problems of ring formation, chamber uniformity, and cover staining were resolved in the

final small-scale tests at Goddard. The pilot facility will be used to duplicate these results.

The question of cycle times was discussed in the

process description. A conservative estimate of the

total treatment time ranges from 55 to 72 hours.

A goal of the pilot plant studies is to reduce this,

if possible, to 48 hours. This would greatly increase

the number of books that could be processed and

lower the costs.

The rate-limiting step appears to be the dehydration step. The time it takes for water to diffuse out

of the books will depend on the rate at which the

chamber can be pumped to a rough vacuum, and

the rate at which the book’s temperature can be

controlled. The chamber vacuum pump is sized to

bring the chamber down to a rough vacuum (about

2:5 torr2) in 12 hours. However, pumping too fast

may lower the book temperature too much. A warm

nitrogen gas step would then be required to raise

the temperature of the books back to a higher temperature. Book configuration may also affect the

time needed for this cycle. Book carts and spacers

2A mcasu rc of absolute pressure in mill imcters of mercu r}- 1 tot-r

is equii’alcnt to 1 /760 of atmospheric pressure.
34

must be designed to allow books in the interior of

a stack enough time to get to the desired moisture

content.

The principal issue in scaling up to a commercial plant is whether to achieve the desired capacity with one larger chamber (up to 7,500 books per

run) or to design multiple chambers of a size close

to that of the pilot plant chamber. There are many

reasons that favor the latter approach.

Multiple chambers would basically reduce the

amount of down time in the system. If one chamber is shut down, the others can continue to operate. It also allows the various subsystems—i. e., the

DEZ recycling pump, the chamber vacuum pump,

etc. —to operate more continuously reducing the

chance of failures associated with the startup and

shutdown of those components.

Also, keeping the chamber not much larger than

the pilot plant chamber will introduce less uncertainty in reproducing the flow characteristics

achieved in the pilot plant. Although most of the

scaling up associated with a (large) single-chamber

design would be relatively straight forward, reproducing the flow characteristics in a greatly enlarged

chamber would not.

The principal disadvantages in going to a multiple-chamber design would be some increase in the

complexity of operations. Cost factors would also

need to be evaluated. Depending on their design,

several multiple chambers may cost more or less

than a single large one. Also, the chemical plant

section for multiple chambers could possibly be

smaller and lower cost. Finally, with multiple chambers, the control of the process would require careful

monitoring by the distributive control system and

greater complexity in the interlock design and operations which may also affect cost.
Chapter 3

Effectiveness of the DEZ Process
CONTENTS

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Goals and Criteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Library of Congress Test Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Library of Congress Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Acid Neutralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Deposition of Alkaline Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Uniform Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + . . . . . . . . . . . . . ..+... 42

Life Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Figures

Figure No. Page

8.

9.

10.

11.

12.

13.

14.

15.

16.

MIT Fold Test t1/2 v. Zinc Oxide Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Typical Distribution of Slurry pH Values by Untreated and DEZ Treated

Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

NASA-5,000 Book Test, pH Results From Book Papers at Different Chamber

Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

NASA-5,000 Book Test, Zinc Oxide (Ye) Results From Book Papers at

Different Chamber Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Titrated Alkaline Reserve of Page v. Page Number for a 508-Page Book

Treated in Experimented Run SST #13..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Titrated Alkaline Reserve of One Page in a Book From Experimental Run

SST #13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

MIT Folds (l/2kg) v. Days in Humid Oven for Foldur Kraft Paper Treated

in Experimental Run SST #6.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

MIT Folds (l/2kg) v. Days in Humid Oven for Allied Superior Paper

Treated in Experimental Run SST #4....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

MIT Folds (l/2kg) v. Days in Humid Oven for Newsprint Paper Treated in

Experimental Run SST #8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Tables

Table No. Page

3.

4.

5.

6.

7.

8.

9.

Comparison of pH Before and After DEZ Treatment and Zinc Oxide After

DEZ Treatment for Various Papers. . . . . . . . . . . . . . . . . . . . . . . . . .....+... . . . . 41

pH and Zinc Oxide Content of DEZ Treated Papers for Various Locations . . . 41

Drop in pH Treated v. Untreated Paper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Results of the G.E. Tests for Uniform Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Drop in Fold Endurance Treated v. Untreated Paper . . . . . . . . . . . . . . . . . . . . . . 45

Drop in Fold Endurance Treated v. Untreated Paper . . . . . . . . . . . . . . . . . . . . . . 45

Reaction of DEZ Vapor With Various Book Materials . . . . . . . . . . . . . . . . . . . . . 46
Chapter 3

Effectiveness of the DEZ Process

INTRODUCTION

The purpose of this chapter is to assess the effectiveness of the DEZ process and the expected

benefits of the Library’s program. The Library of

Congress has performed a substantial number of

tests during the development of its process and has

made the results available for this study. Over the

past several years, however, the Library had not

widely disseminated this test data or published the

results. Upon the request of OTA, the Library has

written a report of its small-scale test program at

NASA. This is separately available from OTA or

the Library upon request.1 This, together with data

1 I.ibrar} of Congress, Prc’srnation Research and Testing Office

Report on the ‘1’hirteen Small-Scale Test Runs of the L>EZ Deacidififrom the original patent, G.E. and NASA contractor reports, and interviews with the Library form

the basis of this chapter.

This chapter is divided into four major sections:

1) Goals and Criteria describes the objectives of the

Library’s deacidification program; 2) Library of

Congress Test Methods describes procedures used

by the Library to evaluate DEZ treatment; 3) Library of Congress Test Results; and 4) Discussion

presents OTA conclusions about the effectiveness

of the DEZ process.

cation Process at Goddard Space Flight Center in 1983, 1984, 1985;

December 1987, unpublished.

GOALS AND CRITERIA

The goals of the Library’s process development

program relating to effectiveness are:

● prolong the life of paper in books and other

formats as long as possible,

. no Preelection, and

● capable of treating the entire book collection

in 20 years.

In order to achieve these goals, the Library has

articulated a set of criteria that the process must

satisfy:

●

●

●

●

●

●

●

a demonstrated improvement in book life,

a complete and permanent neutralization of

all acids,

an adequate and permanent deposition of an

alkaline buffer,

uniform treatment within each book and

throughout all books,

compatibility with all other book materials,

capable of treating about 1 million books per

year, and

capable of treating other formats, e.g. , boxed

manuscripts, maps.

The life of a book can be defined as the time it

takes for a book to deteriorate to a point where its

information is no longer available. There are no

standards, however, by which to measure deterioration or at what point it has rendered the information in a book inaccessible. A commonly used

measure of book life and the one used by the Library is the decline in fold endurance. Fold endurance is the number of times a piece of paper can

be folded, either 90 or 2700, under tension, before

it breaks. The fold endurance of paper will decrease

with age and is indirectly related to the degree to

which the paper has degraded. The Library compares the decline in fold endurance of treated and

untreated paper to demonstrate the effectiveness of

its process. The results of fold endurance tests are

influenced by depolymerization of the cellulose molecule, and by changes in the degree of crystallization and crosslinking—all chemical changes which

are mainly responsible for the degradation of paper upon aging. The Library uses this test because

they have concluded that it is more sensitive than

other commonly measured physical properties, such

as tensile strength, resistance to tear, wet strength,

or burst.

The decline in fold endurance must be measured

over time. Because the life of modern papers may

37
38

range from 50 to 100 years, natural aging is not

practical for analysis. Therefore, treated and untreated papers must be aged artificially. Artificial,

or accelerated, aging is done in an oven under controlled temperature and humidity. The assumption

is that the mechanisms responsible for natural aging

can be accelerated if the paper is exposed to elevated temperatures. A rough correlation is that 72

hours at 1000 C is equivalent to 25 years of natural aging. The actual relationship will vary from

paper to paper and must be determined by taking

measurements at at least two different aging temperatures. It may also depend on the initial age of

the paper.

To prolong the life of the books as much as possible, the Library maintains that the process must

completely and permanently deacidify all of the

acids present in the paper. Stable papers have a pH

of at least 7. The Library has set a pH of 7 as the

minimum for adequate deacidification. If the pH

of paper gets too high it actually becomes too alkaline and can begin to deteriorate by other mechanisms.

The deacidification must also be permanent so

that the treated book does not become untreated,

i.e., so that part or all of the byproducts formed

during deacidification do not spontaneously react

and revert back to acids over time. As mentioned

earlier, the Library ruled out the amine-based processes for this (and other) reasons.

In addition, the process must deposit a sufficient

amount of permanent alkaline buffer throughout

the book. A treated book can become acidic again

due to the continued conversion of alum, lignin,

and other book materials to acids, or from the absorption of pollutants from the environment. A permanent alkaline buffer will protect against this reacitification. Again, the alkaline buffer must be

permanent and not decompose or migrate out of

the paper, to provide maximum protection.

An adequate amount of buffer is required to provide the protection over a long period of time.

Originally the Library considered a goal of 2 to 3

percent zinc oxide. The Library has since determined that for the DEZ process, depositing 1.5 to

2.0 percent by weight of zinc oxide in the paper

will provide the best enhancement of permanence

at the lowest cost (see figure 8).

Of course, uniform treatment is necessary to ensure that the entire book is protected. Areas that

are not treated, or acids that are not neutralized,

will continue to degrade. For books, it is imperative that the treatment reaches into the spine of the

book.

Compatibility with other materials found in

books, such as adhesives, labels, covers, inks, pigments, coatings, etc. , causing no visual or tangible differences in the treated paper means that no

preelection or sorting would be necessary prior to

treatment. To some extent compatibility is an aesthetic issue, but one that is insisted on by most

librarians and curators. However, there are practical reasons as well. For example, if inks or colors

run or transfer, or if labels fall off, information may

be lost.

The Library has set for itself the goal of treating

all of its book collections within a 20-year period.

This means that between 1 and 1.5 million books

must be treated each year. The Library also intends

for the process to have the ability to easily and effectively treat other formats because all paper collections have similar acid embrittlement problems.

Figure 8.- MIT Fold Test t1/2 v. Zinc Oxide Content

(three test papers aged at humid conditions –

90°C and 5096 RH)

20

Newsprint

10 Foldur Kraft

o

0 1.0 2.0 3.0

Zinc oxide in paper (%)

SOURCE: Library of Congress
39

LIBRARY OF CONGRESS TEST METHODS

The Library uses a variety of standardized tests

described below to evaluate the effectiveness of their

process.

To demonstrate the effectiveness of the DEZ

process in extending the life of a book, treated and

untreated papers are artificially aged in an oven

at 900 C and a relative humidity, RH, of 50 percent and a dry oven at 1000 C and O percent RH.

Aging takes place for up to 100 hours with samples pulled at 5- to 10-hour intervals. Following

aging, specimens taken from both the treated and

untreated paper are then tested in an M.I.T. fold

endurance machine. (TAPPI Standard T 511 su69, “Folding Endurance of Paper.”) The machine

repeatedly bends the paper specimen through a

2700 angle, with 0.5 kg of tension (a modification

of the TAPPI standard) on the paper. The number of times the paper is bent before it breaks is

recorded, and represents the fold endurance. By

comparing the difference in the loss of fold endurance, after similar accelerated aging times and conditions, the difference in the rate of deterioration

between the treated and untreated paper can be determined. Alternatively, comparing the number of

days (i. e., years) it takes before the paper has lost

all of its fold endurance can provide a measure of

how long the life of the book has been prolonged.

This measurement is usually performed on test

papers—not papers from actual books. Some researchers outside the Library have noted that fold

endurance is sensitive but over a relatively narrow

range in comparison to tensile or certain other

measurements and that fold endurance works best

for new, relatively strong papers.

To determine whether deacidification has been

complete, the Library determines the average pH

of the paper using a modified standard TAPPI test. z

Randomly selected pages from a randomly selected

book, are ground up into a slurry and the pH of

the slurry measured by titration. This does not give

an indication of the uniformity of treatment across

the page, but is a more sensitive measurement of

pH. Specific pH values mentioned in this chapter

are the results of slurry tests.

To ensure that enough zinc oxide has been deposited, the Library randomly selects a page or a

portion of a page from a randomly selected book,

macerates the paper into a slurry and determines

the amount of zinc oxide present by acid titration.

Nonquantitative tests are used to demonstrate

completeness of treatment. The Library determines

whether deacidification has been complete by spraying randomly selected pages from randomly selected

books or paper with a pH-indicating solution. If

the paper has been completely neutralized, the entire page, including down into the spine of the book,

will be a color associated with a pH of 7 or greater.

2TAPPI Standard T 509 0s-77; ‘ ‘Hydrogen Ion Concentration (pH)

of Paper Extracts—Cold Extraction Method’; the Library modification is to use a blender to produce a slurry,

Photo credit: Library of Congress

Fold endurance test apparatus

Photo credit: Llbrary of Congress

pH test apparatus
40

If the treatment has not been complete, areas on

the page will be a color associated with a pH less

than 7.

To ensure that the deposition has been uniform,

the selected pages are placed under an ultraviolet

light. The zinc oxide will fluoresce, revealing its

location on the page. These visual observations

have been confirmed by more elaborate quantitative measurements of uniformity across a page

using x-ray fluorescence and atomic adsorption

techniques. Additional evaluations of uniformity

of zinc oxide deposition have been made using scanning electron microscope techniques. The microI scope scans sections of the paper with electrons.

When hit by the electrons, the different elements

in and on the paper, will emit their own characteristic x rays. By just sensing the x rays characteristic of zinc, the location of zinc can be determined. The intensity of the x rays also gives a

semi-quantitative measurement of how much zinc

is present.

Visual inspection has been the principal method

used by the Library to determine whether the treatment has been compatible with all other book materials. Pages of books were inspected for yellowing or other discoloration, transfer of colors from

one page to another, running of inks, the accumulation of reaction byproducts, etc. The books were

also inspected for any loss of adherence in areas

where glues or other adhesives are used.

The Library at times has measured the brightness before and after treatment, as well. Brightness

is determined by measuring the paper’s blue reflectance. The paper is lit with white light from a standard lamp. The light reflecting off the paper passes

through a blue filter and its intensity recorded by

a photo cell. The output of the photo cell is calibrated with a standard of known reflectance.

The Library has also conducted a test to determine whether any reactions occur between the DEZ

and a few of the most common materials to be

found in or on books. This is discussed further in

the following section.

Because of its priority to deacidify books, thus

far, the Library has only conducted a limited number of tests on other formats. Zinc oxide contents

and pH were measured on maps treated in the G.E.

tests. The Library plans more thorough testing of

other formats in 1988 at the Texas Alkyls pilot

plant.

LIBRARY OF CONGRESS TEST RESULTS

Published documentation of the DEZ process’

effectiveness is limited. Many tests have been run,

and much data has been accumulated. However,

the external reporting of the results has been limited

in the view of some other preservation scientists.

The principal documentation of the process’ effectiveness is found in the process patent which contains the results from a collection of early lab tests

and in the list of publications in appendix E. These

results, and some selected data from the larger scale

tests, have convinced the Library that if they can

achieve a uniform deacidification and a uniform

deposition of 1.5 percent zinc oxide in the books,

the life of the books can be extended between three

to five times. All subsequent work has been devoted

to achieving these results in scaled-up systems. Most

of the data that have been collected have been pH

measurements, zinc oxide content, and some fold

endurance measurements. Since most of the development has involved optimizing the process, these

data include good and bad results. Since the Library has not published a comprehensive report on

the results of all past experiments, OTA requested

the Library to prepare a report on the most recent

set of tests conducted at NASA in 1985-86. That

report is available separately from the Library.

Acid Neutralization

The effectiveness with which DEZ neutralizes

acids is fairly well-established. DEZ is known to

be an avid scavenger of hydrogen ions and therefore should react directly with all acids very quickly.

Test results support this. In data presented in the

patent, single sheets of various types of papers were

treated for 1 hour. The results, shown in table 3,

indicate that DEZ can quickly neutralize the pH

of a wide variety of acidic papers, including news-
41

Table 3.—Comparison of pH Before and After DEZ Treatment

and Zinc Oxide After DEZ Treatment for Various Papers

0

/0 zinc oxide in

pH before pH after paper after

Paper treatment treatment treatment

Newsprint . . . . . . . . . . . . . . . . . . . . . . .

Offset paper (LCIB) . . . . . . . . . . . . . . .

Made Rite offset . . . . . . . . . . . . . . . . .

Whatman filter paper #1 . . . . . . . . . . .

100°/0 rag ledger (GPO#773). . . . . . . .

Old book paper (rag)

published 1820 . . . . . . . . . . . . . . . . .

Berestoke text (handmade) . . . . . . . .

Crane’s distaff linen antique laid . . .

Mead bond . . . . . . . . . . . . . . . . . . . . . .

5.4

5.8

5.6

6.6

6.2

5.3

4.7

5.2

5.9

7.8

7.9

8.2

8.1

8.0

8.1

7.6

7.7

7.7

0.89

2.02

1.48

0.94

1.37

0.79

1.42

0.54

0.82

NOTE: These data were taken from Patent #4,051,276 (Sept. 26, 1977). Papers were treated for 1 hour (probably individually)

during Library lab tests prior to 1977

SOURCE: Library of Congress.

print. In one case it raised the pH from a low 4.7

to a slightly alkaline 7.6. In another experiment,

32 sheets (16 sheets of bond and 16 sheets of newsprint) were stacked inside the pressure cooker and

treated. pH measurements of the top, middle, and

bottom sheets showed that DEZ could effectively

penetrate and neutralize acids (see table 4). In

another experiment, a book was cut in half and

treated. Pages throughout the book were deacidified, the pH after treatment averaged 7.36, showing that DEZ could effectively penetrate a closed

book. Figure 9, showing results of pH measurements from NASA test runs, also indicates that a

variety of papers with different acid contents can

be fairly uniformly brought to pH values clustered

in a narrow range (+/-0.5) around 7.2.

The byproducts of the neutralization are zinc

salts. The principal reaction is believed to be between DEZ and sulfuric acid (the major acid species in paper) to form zinc sulfate. The original sulfuric acid was formed by water reacting with the

alum (aluminum sulfate). Water, too, can react

Figure 9.-Typical Distribution of Slurry pH Values

by Untreated and DEZ Treated Books

28

28 Treated

 2 4

2

n

“ 3.8 4.2 4.6 5.0 5.4 5.8 6.2 6.6 70 7.4 7.8 8.2

pH

SOURCE: Library of Congress

with zinc sulphate, to reform acid. Some researchers

have postulated that the reformation of acid from

zinc sulfate could lead to a depletion of the zinc oxide buffer more rapidly than anticipated. However,

the Library has investigated this and concludes that

Table 4.—pH and Zinc Oxide Content of DEZ Treated Papers

for Various Locations

Bond paper Newsprint

pH %ZnO pH %ZnO

Untreated . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 0 4.9 0

Treated:

Sheet #1 (top of pile) . . . . . . . . . . . . . . 7.7 0.81

Sheet #16 (center of pile). . . . . . . . . . . 7.7 0.62

Sheet #17 (center of pile). . . . . . . . . . . 7.7 0.58

Sheet #32 (bottom of pile) . . . . . . . . . . 7.7 0.81

SOURCE: US. Patent #4,051,276.
42

the acidity contributed by zinc sulfate is much less

than the buffering provided by zinc oxide. Test results from paper treated in a liquid solution of DEZ

and hexane show that the pH of the treated paper

can be maintained after aging, whereas the pH of

the untreated paper drops dramatically (see table

5). These tests have not been performed with papers

treated with DEZ vapors, nor was it stated how

much zinc oxide was deposited or consumed.

Deposition of Alkaline Buffer

Patent data from early lab tests shows that a wide

range of zinc oxide contents can be achieved. In

the papers treated for 1 hour, zinc oxide contents

ranged from 0.54 to 2.02 percent. (See table 3.)

Zinc oxide contents in both the sectioned book and

in the stack of papers that were treated, showed zinc

oxide contents well below 1.5 percent. In the experiment that exposed a stack of papers to higher

amounts of DEZ, zinc oxide contents up to 3.69

percent were achieved. Zinc oxide contents as high

as 9 percent have been deposited. The Library plans

to conduct more extensive tests of this type during

their current pilot plant tests.

Table 5.—Drop in pH Treated v. Untreated Paper

pH

Paper Before aging After aging 12 daysa

Offset GPO #21056:

Untreated . . . . . . . . 6.8 4.6

Treated . . . . . . . . . . 7.6 7.1

aAged at go oc and 50 percent relatiVe humidity.

SOURCE: U.S. Patent #4,051,276.

Uniform Treatment

When treating large numbers of books, complete

and uniform deacidification throughout the entire

batch becomes a major issue. Tests at G.E. (400

book tests) and at NASA (one 5,000-book test and

thirteen 100-book tests) confirm that all books can

be completely and uniformly deacidified if enough

DEZ and enough time are provided. If enough time

or DEZ are not provided, or if the books are not

positioned in the chamber to be exposed to DEZ,

or if the DEZ does not circulate properly, some of

the books will not be completely treated. Deacidification is a diffusion limited process. The outer edges

of the outer pages are deacidified first. The center

of the center page is deacidified last. The results

of the G.E. tests are shown in table 6. In two of

the tests deacidification was incomplete. The effect

of poor DEZ circulation is demonstrated by complete lack of deacidification of books located near

the top of the 5,000-book chamber. (See figure 10.)

Complete deacidification in these tests was determined by spraying selected pages with a pH indicator solution. Average pH determinations were

made by cold extraction titration. Because the results of the NASA tests were mixed, it is important that the pilot plant tests currently underway

demonstrate that reasonable uniformity can be

achieved under a set of standard operating conditions and with the expected variety of materials to

be treated.

When uniform deacidification does occur it appears to be very uniform, regardless of book locaTable 6.—Results of the G.E. Tests for Uniform Treatment

Book DEZ mixture Drying time Exposure

Batch weight weight (hours) Pressure Time Qualitative results Typical ZnO deposita

1 . . . . . . 960# 32# 443/4 625 torr 24 hrs Only partial Books 10/0, maps 1.85°/0

deacidification

2 881# 56# . . . . . . 893/4 25 torr 26 hrs Total deacidification Books 0.573°/0, maps

600 torr 114 hrs 2.70/o

3A . . . . 1 ,086# 70# 117J/z 36 torr 29 hrs Mixed—300/0 to 100°/0 Books 1.04°/0, single

deacidification exposure

3B . . . . 30# 7 20 torr 24 hrs Mixed—30% to 100°/0 Books 1.43°/0, maps

deacidification 1.57°/0, double

exposure

4 . . . . . . 820# 26# 124 23 torr 24 hrs Total deacidification

16# 43 torr 72 hrs

aoata based on deacidified portions-per George Kelly, Libray of Con9ress.

SOURCE: General Electric, Valley Forge Space Center, Report to the Library of Congress, December 1978.
43

Figure 10.– NASA-5,000 Book Test, pH Results

From Book Papers at Different Chamber Locations

books

Completely

deacidified

Typical page from a treated book from three locations shown

SOURCE: Library of Gmgrass

tion because DEZ appears to react rapidly and completely with the acids it contacts.

The complete and uniform deposition of 1.5 percent zinc oxide has been more difficult to achieve

in large-scale tests. The G. E. tests did not achieve

the 1.5 percent zinc oxide buffer with the amounts

of DEZ and time provided. The 5,000-book NASA

test achieved 2.2 percent zinc oxide in books located in the lower part of the chamber. But, similar to deacidification, the poor circulation of the

DEZ affected the amount of zinc oxide that got deposited in books elsewhere in the chamber. Books

in the middle of the chamber, which were effectively

neutralized under the less than optimal treatment

conditions had low and non-uniform deposition of

zinc oxide. Furthermore, the pulsing of the DEZ

into the chamber showed up as concentric rings of

zinc oxide with varying concentrations. Outer rings

had zinc oxide contents of 2.2 percent, while the

inner rings had zinc oxide contents of less than 0.3

percent. As with deacidification, zinc oxide deposition occurs first on the outside edge of the outer

pages and occurs last in the center of the center

page. Books at the top of the 5,000-book chamber

had no zinc oxide. (See figure 11. )

The changes made in the smaller scale NASA

tests—i.e. , the continuous feed of DEZ into the

chamber at high rates to ensure good circulation—

eliminated the zinc oxide rings, in fact figures 12

and 13 shows the uniformity that was achieved in

Figure 11.-NASA-5,000 Book Test, Zinc Oxide (%)

Results From Book Papers at Different

Chamber Locations

o% Top of

chamber

0.3% - 2.2%

0.3% - 2.2% Bottom of

chamber

Typical book paper from a treated book located

at middle or bottom of chamber

SOURCE: Library of Congress
44

Figure 12. -Titrated Alkaline Reserve of Page v. Page

Number for a 508-Page Book Treated in

Experimental Run SST #13

1.5

1

0.0 I I 1 I I 1 1 I 1 1 I

0 50 100 150 200 250300 350400 450500

Page number

SOURCE: Llbraty of Congraaa

one book in one of the final small-scale tests. These

data were derived from randomly selected pages

from randomly selected books from the small-scale

runs. When placed under an ultraviolet light, zinc

oxide deposition on these pages appeared uniform

throughout a given book and independent of book

location in the chamber.

The range in zinc oxide contents is the result of

a number of factors. Not only does it depend on

the amount of moisture left in the paper, but also

on the amount of DEZ vapor available during treatment, time, and the type of paper being treated.

Papers differ in the amount and type of cellulose

that is used and the type of chemicals that have been

added during, or remain after, manufacture. If any

of these are acidic, additional DEZ will be needed

for their neutralization. Characteristics of paper

such as thickness, porosity, surface texture, etc. also

affect the rate at which the DEZ can impregnate

the paper. However, the data indicate that given

enough DEZ and time, the desired zinc oxide buffer

can be fairly uniformly deposited. The DEZ process appears to have excellent ability to uniformly

neutralize acids and deposit 1.5 to 2.0 percent zinc

oxide effectively. The variation in the amount of

zinc oxide deposited in a variety of book papers

treated in the same batch is being investigated at

the pilot plant.

Figure 13.-Titrated Alkaline Reserve of One Page in a Book From

Experimental Run SST #13

1.6% ZnO

a.

b. 1 .4%

c. 1 .5%

d. 1 .7%

\

/

e.

.6%

f.

1 .4%

0.

1 .3%

h.

1 .4%

ZnO

Top to bottom Side to side

SOURCE: Libraty of Congrass
45

Life Extension

The Library claims that DEZ treatment extends

the life of books by three to five times. These claims

are based on numerous fold endurance tests of

treated and untreated paper. Tables 7 and 8 show

the comparison for some of those papers treated for

just 1 hour, and paper treated twice for 3 hours.

These data indicate that the decline in fold endurance during aging appears to be slower in treated

papers vs. untreated papers. Similar results from

larger scale tests have been presented by the Library (see figures 14, 15, and 16).

How directly and accurately these fold endurance test results can be translated into a confident

prediction of life extension for actual books treated

is subject to debate. Tests on actual books many

years after treatment may provide more confident

predictions.

Table 7.— Drop in Fold Endurance

Treated v. Untreated Paper

(MIT test–O.5 kg)

Equivalent years of aginga

Paper o 67 117

Newsprint:

Untreated . . . . . . . . . . . . . . . . 118 3.5 0.6

Treated (1 hr.) . . . . . . . . . . . . 135 60 36

Mead bond:

Untreated 465 92 54

Treated (1 hr.) . . . . . . . . . . . . 476 134 122

Offset GPO JCP-A60:

Untreated . . . . . . . . . . . . . . . . 604 240 145

Treated (1 hr.) . . . . . . . . . . . . 652 441 315

aAged at go cc at so percent relative humidity.

SOURCE: U.S Patent #4,051,276,

Table 8.—Drop in Fold Endurance

Treated v. Untreated Paper

(MIT test–O.5 kg)

Days of aginga

Paper 3 6 12

Newsprint:

Untreated . . . . . . . . . . . . . . . . 54 8 0.9

Treated (total 3 hrs.) ., ... , . 65 48 41

JCP-A60 offset:

Untreated . . . . . . . . . . . . . . . . 641 391 130

Treated (total 3 hrs.). . . . . . . 701 652 337

aA*ed at w c at 5r) percent relative humidity.

SOURCE U.S Patent F4,051 ,276,

Figure 14.-MIT Folds (1/2 kg) v. Days in Humid

Oven for Foldur Kraft Paper Treated in

Experimental Run ‘SST #6

E

2.3% ZnO

90oC and 50% RH

I 1 I 1 I

0 20 40 60 80 100 120 140 160 180200

Days in humid oven

Data points are means of 12 determinations, 9996 confidence hmits of means shown

SOURCE: Library of Congress

Figure 15.-MIT Folds (1/2 kg) v. Days in Humid

Oven for Allied Superior Paper Treated in

Experimental Run SST #4

1.2% ZnO

1,000 90o C and 50% RH

100 ~

10 ~

1 I 1I I u

0 20 40 60 80 100 120 140 160 180200

Days in humid oven

Data points are means of 12 determinatlons, 99% confidence Iimlts of means shown

SOURCE: Library of Congress

Compatibility

In most cases, a paper’s brightness does not appear to be affected by the DEZ treatment. In lab

tests, the brightness remained virtually unchanged

immediately after treatment and after aging.

Visual inspection of books treated in the larger

scale tests showed no indication of incompatibility

between the DEZ and other book materials. The

Library also conducted two tests on 10 common

book materials to determine whether DEZ reacted

with these materials. First, a Fourier Transform
46

Figure 16.-MIT Folds (1/2 kg) v. Days in Humid Oven

for Newsprint Paper Treated in Experimental

Run SST #8

2.2% ZnO

1,000 90° C and 50% RH

100

10

i

‘ o 20 40 60 60 100 120 140160 180200

Days in humid oven

I Oata points are means of 12 determinations; 99% confidence Iimtts of means shown I

I SOURCE: Libra~ of Congress

Transmission Infrared Spectrum from a sample of

each material was first generated. The material was

then exposed to DEZ vapors, under process conditions, for 3 to 5 days. After exposure, a second

infrared spectrum was taken. If any reaction between the material and the DEZ had taken place,

the spectrum would have changed. Also, the temperature, pressure, and composition of the gas inside the test chamber was monitored to detect any

evidence of a reaction. The other test was an x-ray

fluorescence study. All but one of the materials

tested negative, i.e., no reaction with DEZ was detected (see table 9). Nitro-cellulose, a material used

in cloth book covers, did show some indication of

reaction, resulting in clouding of the clear film.

Some researchers have been concerned that the

breakdown of nitro-cellulose can cause further

degradation but the Library believes this is not a

problem.

Zinc oxide can promote the photodegradation of

paper under certain conditions.3 The Library exposed treated and untreated papers to radiation

from a sunlamp placed 24 inches from the paper

in an oven at 600 C and 60 percent relative humidity. Specimens were then tested for fold endurance. The treated papers had much lower fold endurances. The Library does not consider this to be

a major problem, however, since books are stored

in such a way to minimize their exposure to light

and ultraviolet radiation.

3George B. Kelly and John C. Williams, ‘‘Inhibition of Light Sensitivity of Papers Treated With Diethylzinc, presented at the Annual Meeting of the American Chemical Society, Washington, DC,

September 1979.

Table 9.—Reaction of DEZ Vapor With Various Book Materials

Observations

Material FTIR Spectruma XRFb Visual

Cellulose . . . . . . . . . . . . . . . . . . . No change <0.50/0 Zn No change

Lignin . . . . . . . . . . . . . . . . . . . . . . No change <0.50/0 Zn No change

Gelatin . . . . . . . . . . . . . . . . . . . . . No change <0.50/0 Zn No change

Starch. . . . . . . . . . . . . . . . . . . . . . No change <0.5°A Zn No change

Polyvinylacetate . . . . . . . . . . . . . No change <0.5°/0 Zn No change

Polyvinylalcohol . . . . . . . . . . . . . No change <0.50/0 Zn No change

Polyethylene . . . . . . . . . . . . . . . . No change <0.50/0 Zn No change

Polypropylene . . . . . . . . . . . . . . . No change <0.50/0 Zn No change

Nitrocellulose . . . . . . . . . . . . . . . Small decrease—No <0.50/0 Zn Slight opacity

Fluorescent brighteners . . . . . . — — Some decrease

aFOurler transform infrared.

bX-ray fluorescence.

SOURCE: Library of Congress.
47

DISCUSSION

The Library has developed a unique process that

can uniformly neutralize the acids and deposit an

alkaline reserve in books en masse. The process can

deposit a uniform alkaline reserve independent of

the variation in book acidity. Preliminary tests indicate that the process can also treat multiple

formats.

The process appears to be compatible with inks,

colors, pigments, and most other book materials,

reducing the need to screen books for treatment and

maximizing the number of books that can be

treated. This conclusion is based on visual inspection, and includes two chemical tests that indicated

DEZ does not react with 10 common book materials. The one exception is nitro-cellulose, a polymer

material commonly used in book covers. The observed change is an increase in opacity in a clear

film of the material.

OTA notes, however, that there is a lack of clear,

documented, scientific understanding about what

effect deacidification has on paper chemistry beyond the neutralization of acids and the deposition

of alkaline buffers.

The Library contends that, though there may be

some reactions undetected in their studies, the accelerated aging data on alkaline treated papers

shows that undetected reactions do not appear to

cause deterioration of the paper.

Of particular interest to some paper chemists is

what effect the process has on the concentrations

of cellulose functional groups that are capable of

oxidizing and forming new acids. For example, it

was hypothesized in the patent that DEZ may stabilize the cellulose’s aldehyde groups. If this is so,

an important source of new acid may be eliminated.

More sensitive analysis may be able to determine

whether this reaction actually occurs. The Library

intends to conduct such studies in the future.

The chemical effects associated with deacidification will probably affect other degradation mechanisms. Oxidation is known to be affected by pH.

Photodegradation, pollution, and biological attack

may also be affected. The Library and others have

raised the concern that zinc oxide increases the sensitivity of paper to photodegradation. Library tests

to date have been inconclusive and a definitive evaluation of photodegradation is planned for during

current pilot plant tests. However, since the Library

collection is stored under very low ultraviolet light

levels, they are less concerned about this problem

than other libraries may be.

It is not clear to what extent the process will extend the life of the collection. The Library data suggest that the DEZ process can extend the life of a

book by three to five times. The Library relies solely

on fold endurance for demonstrating the improved

life of treated paper. Although fold endurance is

easy to determine and shows a measurable decline

after accelerated aging, it is a very nonhomogeneous property and will vary considerably from sample to sample. Even averaging over a large number of specimens results in a large degree of

uncertainty due to inhomogeneities within the paper.4 This makes the significance of any data a critical test. On the other hand, fold endurance can

be very useful and maybe the best indicator of paper permanence if the tests are conducted carefully.

The Library vigorously supports their approach to

testing and evaluation as the most comprehensive,

accurate, and appropriate to their needs.5

Some other scientists believe that a critical analysis lacking in the Library’s assessment is the degree of polymerization. This is a direct measure

of the physical integrity of the cellulose chains. A

low degree of polymerization signifies that the cellulose chains have broken into small brittle lengths.

It has been suggested that besides relying solely on

fold endurance, tensile strength and zero-span

strength also can be used to assess mechanical properties and that these could be combined with the

degree of polymerization in an analysis of the process’ effectiveness.

Another criticism is about the methods used by

the Library in its accelerated aging experiments.

The Library has been using a temperatureof900 C

and both dry and humid conditions. Although the

‘B. L. Browning, ‘ ‘The Application of Chemical and Physical Tests

in Estimating the Potential Permanence of Paper and Papermaking

Materials, Preservation of Paper and Textiles (Washington, DC:

American Chemical Society, 1981), pp. 275-285.

5See app. D for suggested tests by the National Bureau of Standards.
48

best temperature at which to age is debatable, it

is generally believed that the lower the temperature, the better accelerated aging will simulate natural aging. Some paper chemists age at 800 C and

only under humid conditions.

The Library has not yet assessed the total impact the deacidification program will have on its

collection, although this is also in their current

plans. A variety of parameters affect the way papers

respond to deacidification. These include the type(s)

of fibers present, the types of fillers and other additives present, and the age of the paper and the

state of chemical degradation that has already

occurred. It is important, therefore, that the various tests performed to assess the effectiveness of the

process be done on papers that are representative

of the paper that will be treated. The Library has

not sufficiently demonstrated that the fold endurance results are typical of those expected for their

collection. Before the effectiveness of the deacidification program and the Library’s current strategy

can be fully assessed, some measurement of benefits must be made. This could be in terms of expected total book life saved or some other appropriate and measurable quantity.
Chapter 4

costs
CONTENTS

Page

Introduction . . + . . . . ....+.... +“~*””ww.+”*+0.0” +“0.”s”o*+*””*** “**.”--***” 51

Cost Estimates for the DEZ Facility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Engineering Development ........”””~.+~. “tt”+””..~+”~~”. ● “””””..+””””. 53

CapitalCOsts— Full-Scale Facility ~......,......=. ....~.~cs”+oo.~0 ““””++.? 53

Facility Operating Costs ...+......+...”o. “~~””0”*”000..+” +OQ””OOOOO*O-00 54

Discussion ...,. . . . . . . . . . . . . . . . . “.”o~~~+”~+o””B* +0..s*+o*o””.**ooo” .-””** 54

l!’igul’e

Figure No. Page

17.DEzprOcess Development History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Tables

Figure No. Page

10. LOG Engineering Development Cost Estimate for DEZMass Deacidification

11.

12.

13.

53

54

54

55

Program ....g.. .. ... .o. s.a ”++sQ ● OO” OOO*OOCSO *O+ ● *o o;*; ***c*”””” ““””+

LOCCapitd Cost Estimate for 1 Million Books/Yem Deacld~fication

Facility . . . . . . . . . .. .........-””++” •~OOOO*O*OO~**OC* ● “*l .;** *;o C*oo-- ●

LOC Operating Cost Estimate for 1 Million BooksNear Deacid~ficatlon

Facility . . . . . . . . . . .. .. ... ... ”+”s”=” ‘“~’”q”~ea”;”;~’. W“”* ***B**””.**-”

OTACapita.l and Operating Cost Estimates forl Mdhon Books Per Year

Deacidification Facfiity. .......+...”.~’~ •“o~c”ocG”~””Q”” ““~”oQo””o*””s.

‘.
Chapter 4

costs

INTRODUCTION

Since the Library of Congress’ process for mass

deacidification has been under development for the

past 15 years, there have been a number of expenditures that could be categorized as research, development, and testing. Figure 17 displays those past

expenditures that can be directly related to the

Library’s mass deacidification program from 1973

to 1988. It should be noted that certain of these expenditures have been for experiments whose purpose was a search for an optimum process and thus

entailed comparison of various chemical treatments

and results. Other expenditures were for experiments with the DEZ process alone and were directed

toward learning the proper techniques for most effective results. The experimental phase can be considered to have ended with the completion of the

13 small-scale tests with books at NASA Goddard

in late 1984. The Library of Congress reports that

expenditures from 1973 through the end of this

phase were about $2.1 million.

If another process were to be pursued for mass

deacidification of the Library’s collection some of

the work already completed on the DEZ process

would need to be repeated; other work may need

to be repeated depending on the status of development of another process. For example, none of the

alternative processes have been subjected to critiFigure 17. - DEZ Process Development History

I

K ●

I Experimental phase

I

I First DEZ Larger

vacuum I gas phase chamber

I

study studies at GE

I

I

First DEZ

work in

solution

DEZ book

treatment

in pressure

cooker

T

73 74 75 76 77 78

13 small

scale

studies

<100 book

at NASA

book

study

I I Estimated at less than $250,000 I

$ * d

$1,663,674 *

I I ~Actual obligated cost

I

4

Engineering

phase

Pilot

I

plant NI I

at NASA Pilot

I

I plant # 2

t

at Texas I

alkylsl 1

Ft. Dietrick .

facility

building I

designed I

$573,570

I

+$2,600,00 0

I

Actual , Estimated ,

facility costs

cost

1 Includes up to twenty operational experiments in pdot facihty

SOURCE: Library of Congress

51
cal independent evaluation of treated materials. The

Library would most certainly need to compare accelerated aging tests (using standard papers), pH

tests, alkaline buffer tests effects on library materials and others, test procedures, and protocols. It

may also be necessary to evaluate certain aspects

of safety, health, and environmental effects of

another process. Therefore, expenditures for experimental work, while essentially completed for

the DEZ process, would need to be increased if other

chemicals, additional treatment, or new processes

were to be considered.

Following the completion of the NASA small-scale

tests, an expenditure of about $574,000 was devoted

to the ill-fated first pilot plant. The Library of Congress considers that sum to” be basically a loss to

the Library, however, engineering and safety lessons were learned and have been applied to later

work.

Starting in 1987 the Library of Congress’ expenditures on the DEZ process can be directly related

to engineering development, construction, and

operation of the mass deacidification facility. For

the purposes of this OTA evaluation, these expenditures can be put into three categories as follows:

1. Engineering Development Costs

—Design and Construction of Pilot Plant

(Texas Alkyls)

—Hazard and Safety Review/Technology

Management

—Initial Health & Environmental Studies

—Pilot Plant Test Program

2. Capital Costs—Full-Scale Facility

—Toxicological Risk Assessment

—Environmental Impact Assessment

—Plant Engineering and Architectural Design

—Plant Construction Management and Inspection

—Materials Handling—Engineering and

Procurement

—Construction of Plant

—Commissioning and Startup Costs

—Contingency Costs

3. Facility Operating Costs

—Personnel—Plant Operations

—Personnel—Book Handling/Transportation

—DEZ Usage

—Utilities and Other Chemicals

—Maintenance Materials and Spares

—Operating Supplies

—Laboratory, Quality Control Costs

—Book Handling, Warehousing Expenses

—Insurance, Taxes and Other Indirect Costs

—Research Allowances and Contingency

—LOC Management Costs

To evaluate the per-book deacidification cost,

OTA considers the first two categories above as capital costs and the third as annual operating costs.

The total capital cost can be converted to an annual cost using an accepted rate of return over an

assumed life of the project. For example, for a 10

percentl annual rate of return over a 20-year project

life, a capital recovery factor2 is 11.7 percent. Therefore, OTA chose to use a 12 percent capital recovery factor in arriving at a per book cost estimate.

The per-book cost of the DEZ facility will also

vary considerably depending on the actual capacity or throughput finally realized when the plant

is built. Since many costs (except for DEZ usage,

certain labor, and supplies) will be fixed when the

plant is operating, a large increase in capacity will

result in a substantial decrease in per-book costs.

Therefore, one of the goals of the pilot plant test

program is to reduce the cycle time (and thus increase the plant capacity) to the most cost-effective

level. The optimum cycle time will not be determined until a series of tests are completed in mid1988. This study therefore assumes a capacity of

1 million books per year for the full-scale plant when

estimating per-book costs.

The actual construction costs for the full-scale

plant are also subject to some uncertainty. Major

decisions on plant configuration-such as the size

and number of treatment chambers—will not be

made until some pilot plant tests are completed and

a design study is done. Also the engineering design

of the full-scale plant will not be started until mid1988. Therefore, capital cost estimates must be considered only preliminary numbers for budgetary

purposes. Plant operating cost estimates, however,

may not be subject to as much variation only beI Approximately the current rate for long-term government bonds.

‘An annual payment that will repay a loan in X years with compound interest on the unpaid balance.
53

cause the major cost categories (labor, DEZ usage,

overhead) will not change significantly even if plant

design changes are made. However, over the 20-

year life of the plant these costs will undoubtedly

change depending on inflation, possible plant improvements needed, and changes in chemical costs.3

The following sections of this chapter present and

discuss the cost estimates that have been prepared

by the Library of Congress for design, development,

construction, and operation of the DEZ mass deacidification facility. Part II of this report presents

available data for alternative processes. While it is

difficult to make cost comparisons because very little of the data are comparable in terms of accuracy

and completeness, OTA has made some initial comparative comments. One basis of comparison is on

the pilot plant level. It should be noted that the Library of Congress’ pilot plant at Texas Alkyls has

a capacity of about 50 books per 8-hour shift using

a 55-hour cycle time even though much of the machinery is sized for a much larger capacity.4 This

3

0TA has not investigated possible cost changes for DEZ but notes

that only one supplier now produces the chemical and future prices

will largely be determined by that supplier. One or two other suppliers could produce DEZ and have in the past, but the market is not

now attractive for them.

4The DEZ pilot also has a number of purposes and its design was

based on the need to conduct a wide range of experiments as well as

engineering tests. Comparisons with other plants, without such design constraints, must therefore take this into account.

Photo credit: Library of Congress

DEZ pilot plant at Texas Alkyls

could possibly be compared (with some caution) to

the Canadian Library plant with a present capacity of 150 books per 8-hour shift; and with a pilot

plant designed, but not built, by the Koppers Co.

with a projected capacity of 100 books per 8-hour

shift. Such a comparison is very rough at this time,

but, when two or more pilot plants of roughly similar capacity begin obtaining actual operating history, more accurate cost comparisons could be

made.

COST ESTIMATES FOR THE DEZ FACILITY

Engineering Development

The costs for engineering development for the

LOC deacidification facility have been assumed by

OTA to include all work associated with designing, constructing, and testing the second pilot plant

at Texas Alkyls. As of this writing, most of those

costs are quite firm but the number of tests (and

thus the costs of tests) may vary before they are completed in mid-to-late 1988. Table 10 displays the

estimated costs of engineering development that

were supplied by the Library to OTA.

Capital Costs—Full-Scale Facility

At OTA’s request the Library of Congress prepared a capital cost estimate for the full-scale deTable 10.—LOC Engineering Development Cost

Estimate for DEZ Mass Deacidification Program

Pilot plant design and construction ... ... .. .$1.9 million

Pilot plant test program. . . . . . . . . . . . . . . . . . . . 0.8 million

Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 million

Total . . . . . . . . . . . . . . . . . . . . ... ... ... ... ..$2.8 million

NOTE: These costs were incurred and obligated in 1987 and 1988.

SOURCE: Library of Congress.

acidification facility. That estimate is in appendix

C of this report. Table 11 summarizes the LOC

cost estimate. Several categories are not included

in the LOC estimate. OTA believes the costs could

vary considerably because of the number of unknowns about the facility at this time. OTA also

believes the cost estimates are low; OTA advisors

are concerned that the plant design assumptions are
54

Table 11.—LOC Capital Cost Estimate for

1 Million Books/Year Deacidification Facility

Item Cost ($ millions)

Building cost. . . . . . . . . . . . . . . . . . . . . . . . . 1,8

Site work . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3

Chemical process facility . . . . . . . . . . . . . . 2.8

Total LOC estimate . . . . . . . . . . . . . . . . . 4.9

NOTES: 1. Costs based on assumption of two separate structures-a support

building and a chemical treatment facility.

2. Chemical plant cost is based on a hypothetical chamber size for four

chambers.

3. Chemical plant assumes hardware similar to pilot plant.

4. Not Included In estimate are: utlllties, site development, emergency

power, contingency.

5. Plant assumed to be located at Ft. Detrlck, MD.

SOURCE: Libra~ of Congress.

too optimistic (e. g., a 36-hour cycle time and few

I backup systems); OTA is concerned because the

full-scale chemical plant cost appears low if compared with budgetary scale-up factors which are used

as rough guidelines in the chemical industry. OTA

has not, however, prepared an independent cost

analysis and therefore its comments on costs must

be considered only as cautionary.

Facility Operating Costs

Table 12 is a summary of LOC estimates of annual

operating costs for the full-scale facility with an assumed capacity of 1 million books per year. (See

app. B for the LOC estimates and assumptions. )

OTA reviewed these costs and considers several

of the categories to be too low. First, projected laTabie 12.—LOC Operating Cost Estimate for

1 Million Books/Year Deacidiflcation Facility

Annual operating cost

Item ($ millions)

Plant costs (chemicals/supplies/

utilities) . . . . . . . . . . . . . . . . . . . . . . 1.0

Operating labor. . . . . . . . . . . . . . . . . . 0.6

Plant overhead . . . . . . . . . . . . . . . . . . 0.1

Administrative costs . . . . . . . . . . . . . 0.1

Total LOC estimate . . . . . . . . . . . . 1.8

NOTES: 1. Operations are 24 hours/day, 350 days/year.

2. Plant assumed to be located at Ft. Detrick, MD, and thus no costs

are Included for taxes, insurance, safety and fire protection, etc.

3. Contractor supervision and operation Is assumed with fee for this at

15 percent of labor cost.

4. No costs are included for book handling and transportation to and

from the Library but this was estimated at S0.70 per book.

SOURCE: Library of Congress.

bor costs are considered low because they do not

make enough allowances for overtime, maintenance, training, turnover, and contingency. Second, the contractor’s fee is considered low because

of the special requirements for experience and competence. Third, costs for Fort Detrick services (e. g.,

security, grounds maintenance, safety, and fire protection) are not included; nor are costs for staff training, drills, and skills upgrading, Finally, book handling and transportation costs are not included

although previous estimates of these costs are noted.

OTA advisors also were concerned that insurance

against an accident did not show up as a cost or

a contingency; and that no allowance was made for

possible increases in the cost of DEZ.

DISCUSSION

There are several difficulties with analyzing the

available cost estimates for the DEZ mass deacidification process. First, a number of design and program management decisions are yet to be made and

these could affect costs substantially. Second, the

cost data presented by LOC does not include some

possible major costs such as book transportation and

handling, plant commissioning, and contingencies.

Third, the LOC estimates appeared to be on the

low side when reviewed by OTA’s advisors. Finally,

a consistent method for projecting total costs and

per-book costs has not been determined.

OTA believes it is important to develop a consistent method and accurate cost projections with

contingencies as soon as possible. Such projections

are important to decisions (yet to be made) about

size or capacity of the full-scale plant. They are also

important if any of the possible alternative processes are to be evaluated. At present it appears that

at least two alternative processes would have much

lower costs than the DEZ process but this conclusion is based on incomplete cost data and no consistent method for comparison.

Even though it may not be accurate, OTA prepared its own very rough estimate of the DEZ program total costs to determine a possible range of

per book treatment cost that may be applied if all

elements are included. This estimate was made only
55

for the purpose of this report. New data could change

it. Final per-book costs are presented as a +/-20

percent range because of the uncertainties involved.

Table 13 displays the OTA estimate of capital

costs, operating costs, and per-book costs.

To derive a total capital cost estimate OTA included the engineering development costs and the

toxicological risk assessment costs. OTA then made

rough estimates of materials handling facilities, and

commissioning costs. OTA also added about a 6

percent contingency.

To derive a total operating cost estimate, OTA

added about 10 percent more labor costs, a higher

contracting fee, and a fee for Ft. Detrick services

to the LOC estimate. OTA then added a book handling and transport cost based on an earlier LOC

estimate.

For a very rough estimate of per-book costs of

deacidification at the LOC facility, OTA has included engineering development and plant construction in one total capital cost estimate. We then assumed a 12 percent per year capital recovery factor

for this total and added the annual facility operating cost to that. The total per book treatment costs

thus determined are from $3.50 to $5.00 per volTable 13.—OTA Capital and Operating Cost

Estimates for 1 Million Books Per Year

Deacidification Facility

Capital cost;

LOC estimate . . . . . . . . . . . . . . . . . . . . ... ... .,$ 4.9 million

OTA additions:

Toxicological risk assessment . . . . . . . . . . . 1.5

Transport and materials handling. . . . . . . . . 0.5

6-month commissioning. . . . . . . . . . . . . . . . . 0.9

Contingency . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5

Engineering development . . . . . . . . . . . . . . . 2.8

Total capital cost . . . . . . . . . . . . . . . . . . . . $11.1 million

Annual operating costs:

LOC estimate. . . . . . . . . . . . . . . . . . . . . ... ... .$ 1.8 million

OTA additions:

Added labor . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1

Added contractor fee . . . . . . . . . . . . . . . . . . . 0.1

Ft. Detrick services. . . . . . . . . . . . . . . . . . . . . 0.1

Book handling and transportation . . . . . . . . 0.7

Total operating costs ... ... ... ... ... ..$ 2.8 million

Per-book costs:

Total capital . . . . . . . . . . . . . . . . . . . . ... ... .. .$11.1 million

Annual capital recovery @ 12 percent . . . . . . . 1.3 million

Annual operating costs , . . . . . . . . . . . . . . . . . . 2.8 million

Per-book cost @ 1 million books/year = . . . . $4.1

*20-percent range of per-book cost = . . . . . . $3.50-$5.00

SOURCE: Office of Technology Assessment, 1988.

ume. A number of OTA advisors believe that the

higher ($5.00) per-book cost is the most realistic

but without a more systematic and detailed estimate this cannot be confirmed.
Chapter 5

Safety

●
CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety-A Critical Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Importance of Safety-The Goddard Accidents . . . . . . .

Importance of Safety-Accident at Ethyl Corp. . . . . . . .

Safety at the Texas Alkyls Pilot Plant . . . . . . . . . . . . . . . . .

Understanding the Physical and Chemical Properties of

Reactants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Design for Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operational Safety. .. .. .. .. .. .. .. .. .. .$. ... ....$..

Safety Management and Review . . . . . . . . . . . . . . . . . . . .

Outside Reviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety of Full-Scale Plant . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Transportation Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Incidents Involving the Transportation of DEZ . . . . . . .

Shipping Plans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Risk coworkers. . . . . . . . . . . . . . . . .

Risk to Public . . . . . . . . . . . . . . . . . .

Risk to Plant . . . . . . . . . . . . . . . . . . .

Risk to Books.. . . . . . . . . . . . . . . . . .

Discussion . . . . . . . . . . . . . . . . . . . . . . . .

Other Safety Issues Related to the Full-Scale Operation

. . . . . . . ...*..., . .

. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . .

● ☛✎✎✎✎✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎✌✎ ✌

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎☛✎✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎☛

18.

19.

20.

21.

Figures

Figure No.

Chronology of Second Goddard Incident . . . . . . . . . . .

Chronology of Second Goddard Incident . . . . . . . . . . .

Chronology of Second Goddard Incident . . . . . . . . . . .

Product Safety Information Sheet for Diethylzinc . . . .

Products

● ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎☛☛✎✎✎✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

● ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

● ✎✎☛✎✎✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎☛✎☛✌✎✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

Page

and

59

59

60

60

64

64

64

67

69

69

70

71

71

72

72

72

72

72

73

73

73

73

Page

. . . . . . . . . . . . . . . . . . . . . 61

. . . . . . . . . . . . . . . . . . . . . 62

. . . . . . . . . . . . . . . . . . . . . 63

. . . . . . . . . . . . . . . . . . . . . 65

,
Chapter

Safety

INTRODUCTION

One of the most serious concerns with the Li- whether DEZ could be handled safely in the future.

brary of Congress’ program and the DEZ process This chapter discusses the hazards that are present

has been safety. Because of the attention given to and the effort the Library has made and must conthe accident during tests at NASA Goddard in tinue to make to manage those hazards to ensure

1986, many critics focused on the question of the safe operation of a full-scale plant.

HAZARDS

DEZ is considered a hazardous material. It is

very reactive with certain compounds and is capable of releasing large amounts of energy. Fire is the

principal hazard and, under certain specific conditions, explosions could occur.

DEZ is pyrophoric, meaning it will spontaneously ignite if it comes in contact with air (or, more

specifically, the oxygen in air). The reaction is very

fast, and releases a great amount of heat. The intensity of the heat is itself a hazard. It could ignite

flammable materials nearby, cause damage to nearby structures or property, or cause injury directly.

The byproducts of the reaction, carbon dioxide,

water, and zinc oxide, are stable. Large leaks or

spills of DEZ could pose a significant fire hazard.

The product of DEZ reactions (ethane gas) can

reach an explosive mixture with air. Under certain

conditions, in unvented containers, DEZ reactions

can also cause a pressure buildup which could cause

an explosive rupture of the container.

DEZ is also very reactive with water. The byproducts are ethane gas and zinc oxide. If liquid

DEZ and liquid water come into contact, the react ion that takes place can be very vigorous, releasing large amounts of ethane gas very quickly.

The reaction between DEZ vapors and water vapor is not as vigorous, especially the reaction between DEZ vapor and absorbed water that takes

place within books during deacidification.

The reaction between DEZ and water also releases heat. Although the amount of heat that is

released is about 10 times less than the amount released during a reaction between DEZ and air, it

is enough to require careful monitoring during deacidification. During normal book treatment conditions, within a processing chamber, the DEZ vapor is circulated at very low pressures and any

reactions with air has been shown to result in only

small temperature increases and no flames or pressure increases. Tests to confirm this have been done

by the Library.

DEZ will begin to decompose at 120° C, into

hydrogen, ethane or other hydrocarbons, and zinc.

Heat is again released. At 1500 C, decomposition

becomes autocatalytic. This means that the heat released will cause decomposition to proceed on its

own and prevent it from being stopped. Autocatalytic decomposition of liquid DEZ would result in

a very rapid and uncontrollable release of gases.

Monitoring and controlling DEZ gas temperature

in the process becomes critical to prevent the

decomposition of DEZ. Early tests with the Houston pilot plant show adequate DEZ temperature

control is possible within safe ranges to prevent autocatalytic decomposition.

The rapid release of gases associated with the

decomposition of DEZ and with reactions between

DEZ and water pose a significant hazard. If they

occur in a contained environment, the resulting

overpressure situation could cause rupture and subsequent fire. Storage vessels in a processing plant

must therefore be designed with pressure relief systems. Explosion is a potential hazard because under certain conditions both ethane and hydrogen

gas mixtures with air are explosive.

59
60

The amount of DEZ that will be used at the deacidification plant (up to 3,900 pounds in storage,

and approximately 50 pounds per treatment) limits

the scope of these hazards. Large numbers of people will not be at risk. However, they do pose significant risks for plant operators, safety personnel,

and the immediate surrounding property. Such

risks can be managed with proper attention to design and safe operating practices. As an example,

the Library intends to locate DEZ storage containers at a distance away from the chemical plant

and provide barriers to contain a potential fire.

Photo credit: Library of Congress

Hooking up DEZ for NASA 5,000-book test

SAFETY—A CRITICAL ISSUE

The potential for fire and explosion associated

with the use of DEZ makes safety a critical issue

for the DEZ process. The basic goal of safety management is to eliminate or reduce to an acceptable

level the risk of injury or damage to personnel, material, or property associated with a given hazard.

There is a generally accepted priority to reducing the risk to personnel and property:

1.

2.

3.

4.

eliminate or reduce the hazard through design and operations,

isolate the hazard,

train personnel to operate around the hazard,

and

provide protective and emergency systems and

procedures.

The use of DEZ precludes eliminating the hazards associated with it. However, the relatively safe

manufacture of DEZ by Texas Alkyls, Inc., and

its use in a number of applications over the last 20

years suggests that the risks can be kept at acceptable levels. This requires a good understanding of

the chemical and physical properties of the materials and processes involved, good design, detailed

and safe operating procedures (including inspection and maintenance procedures), experienced

operators who receive continuous training in operational and emergency procedures, and a good

safety review program.

The importance of these issues as they relate to

the DEZ process can be seen by reviewing the

events leading to the failure of the first pilot plant.

The following discussion is based on the NASA Accident Investigation Board’s Report and discussion

with NASA and

Importance

Northrup personnel.

of Safety—The Goddard

Accidents

Construction of the first DEZ pilot plant at

NASA’s Goddard Space Flight Center was completed in October of 1985. System checks were initiated in October. The first full-scale test, a complete cycle but without the books, was initiated on

December 5. Immediately upon initiating the dehydration phase of that operation, by introducing

liquid water into the chamber, the pressure rose

forcing the door open and a fire broke out in the

chamber. There were two people in the processing area at the time, but there were no injuries.

The fire burned itself out quickly, but not before

causing extensive damage to the chamber and surrounding instrumentation and hardware.

The system was secured and the power turned

off. Cleanup and repairs proceeded through January. In February, procedures were drafted for

deactivating the system and to resume testing.
61

When the system was turned on, a pressure buildup in the line between a condenser and the brine

seal tank was detected (see figure 18). The pressure buildup exceeded the range of the pressure

gauge for that line. The deactivation procedures

were then revised to include relieving the pressure

in the line by first testing the valves for operability, and then to progressively pump the system to

vacuum.

Valves were tested, beginning at the vacuum

pump, and leading back toward the condenser.

When the valve between the condenser and the

brine seal tank was cycled, contents from the brine

seal tank squirted out from a defective seal in the

tank (see figure 19). The seal tank was replaced,

and the valve tests completed. The system was then

progressively pumped to vacuum. When a valve

in a section of line upstream from the condenser

was opened, an explosion occurred in the line between the condenser and the brine seal tank, and

a second fire broke out (see figure 20). The exploChamber

1

sion was of sufficient force to blow out two doors

in the processing area, The subsequent fire burned

out quickly, but caused substantial damage to the

plant and surrounding area. There was one person in the processing area at the time of the accident, but there were no injuries.

The system remained in an unstable condition.

After careful consideration of how to proceed, an

army demolition team was called in to dismantle

the plant.

The apparent cause of the first fire was the presence of liquid DEZ in the chamber. When water

was introduced, the reaction with the DEZ rapidly

evolved ethane gas which blew the chamber door

open. With the door open, air came into contact

with the DEZ and the fire started.

It is not known for certain how liquid DEZ came

to be in the chamber. The apparent cause was condensation of DEZ in the vapor line leading into the

chamber. The line heater for that section of the line

Figure 18.-Chronology of Second Goddard

When system power is turned on,

pressure gauges read an overpressure

condition between condensers and

brine seal tank

1400 torr 120 torr 33 torr

Condenser Condenser

#1 #2

u

Brine

seal

tank

Incident

Oil/oleic

seal tank

Permeation

vacuum

pump

SOURCE: Office of Technology Assessment, 1988
62

Chamber

1

\

Figure 19.-Chronology of Second Goddard Incident (continued)

Blower

#1 #2 o

SOURCE: Office of Technology Assessment, 1988

was working intermittently, and some of the insulation around the line was missing. Due to the configuration of the line as built, liquid DEZ ran into

the chamber instead of away from the chamber.

The explosion and second fire were apparently

caused by brine and liquid DEZ reacting in the condenser. Evidence of brine was found in the condenser, and probably backstreamed into the condenser when the defective brine seal was replaced.

Liquid DEZ must have been present upstream from

the condenser. When the upstream valve was

opened, the liquid DEZ traveled down the line and

into the condenser, and reacted with the brine. The

reaction rapidly produced a large amount of ethane which ruptured the line and caused the fire.

The presence of liquid DEZ in the line was supported by the fact that over 700 pounds of DEZ

was pumped into the system, instead of the 30

pounds called for in the test. This was not immeBrine

seal

tank

diately known, however, because the DEZ tanks

were not on load cells as called for in the design.

It wasn’t until after the first accident that the tanks

were weighed and the discovery was made. The

presence of excess liquid DEZ in the system explains

the pressure buildup that occurred while the system was being repaired.

The general conclusion of the NASA Accident

Investigation Board1 

was that no one involved

“fully appreciated the engineering challenges’

associated with scaling up the continuous DEZ feed

and recycling system. The care and diligence that

went into the design and operation of the 5,000 -

book test was not carried forward to the NASA pilot plant development.

‘Accident Investigation Board

citification Pilot Plant, Building

1986; Sept. 4, 1986.

Report on the Mishaps at the Dea306, on Dec. 5, 1985 and Feb. 14,
63

Figure 20.-Chronology of Second Goddard Incident (continued)

~ Liquid DEZ upstream

DEZ

[ When upstream valve opened \

1

~d

Chamber

r

I

I

( J L J I

Condenser Condenser

#1 #2

Brine backstreams

into condenser when < [

SOURCE: office of Technology Assessment, 198S

u

Oil/oleic

seal tank

Permeation

vacuum

pump

More specifically, the board came to the following conclusions:

(Excerpt from the NASA accident report)

There was a lack of appropriate instrumentation. In general, the system was under instrumented. Pressure gauges did not have a high

enough range to monitor overpressure situations.

There were no pressure relief valves in the lines,

and most notably none in the chamber. Venting

of the chamber was through the door. The use of

semi-automatic valves required that personnel be

present in the processing area during an operation. Also, real time monitoring of the system

would be more appropriate. The presence of liquid DEZ in the chamber was actually picked up

by a thermocouple reading at the bottom of the

chamber. It was recorded on a strip chart but not

monitored by the controller.

There was a failure to install the instrumentation called for by the plant design. The failure to

place the DEZ tanks on load cells was a serious

oversight. With a substance as hazardous as DEZ,

an accurate inventory must be kept.

There was a failure to develop and follow procedures. The contract between Northrup and

NASA requires the development of at least five

procedures; a facility operating procedure that

gives detailed operating instructions for both normal and emergency situations, an operations test

procedure that gives special instructions pertinent

to the test at hand, a pre-start check list, an operations log which records all significant events during operation, and an engineering log that also

records all significant events and all activities and

calculations pertaining to the test. The systems

tests begun in October and the full- scale test in

December were run without test procedures. No

operations or engineering logs were kept. Furthermore, deactivating of the system began before the

clean-up procedures were approved, and they

were revised without review. Also, the poor condition of the insulation on the vapor line leading

into the chamber indicated that there was inadequate routine inspection of the system.
64

There was one significant design deficiency, the ●

piping configuration allowed liquid DEZ to flow

into the chamber rather than away from the chamber. The use of a brine seal tank is questionable.

In the 5000 book test, brine seal tanks were ad- ●

vised against, because of the violent reaction that

occurs between DEZ and brine. Finally, normal

safety procedures were compromised. A Failure

The process should be controlled by an automated process controller to provide real time

monitoring and display and to operate safety

interlocks.

The design, construction, and operations of

the plant should be subjected to a third party

review.

Mode and Effects Analysis ‘was carried out and

presented to a NASA review board. The analysis

was accepted and operation approved. However,

there was no documentation of who received and

approved the report.

Only the results of the analysis were presented

to the board with little or no documentation or

explanation. Approval was granted although necessary procedures were not available. The analy1 sis was not submitted for outside review. And

there was no verification or inspection of the final

construction and installation.

The accident investigation board made the following recommendations:

● The plant should be more fully instrumented,

especially in regards to monitoring the inventory of DEZ. It should also allow remote

operation of the system.

Importance of Safety—Accident

at Ethyl Corp.

Another example of the potential hazards associated with metal alkyls is an accident that occurred

at an Ethyl Corp. facility in 1986. Ethyl is also a

major producer of metal alkyls and the only other

domestic supplier of DEZ (although they have not

produced DEZ in recent years). During the manufacture of a metal alkyl product, a large explosion

occurred. Although details of the accident are not

publicly available, there were some injuries, the

damage was extensive, and the plant had to be

rebuilt.

SAFETY AT THE TEXAS ALKYLS PILOT PLANT

This section discusses the safety of the Texas

Alkyls pilot plant by examining the actions taken

by the Library and its contractors in the following

areas: understanding of the physical and chemical

properties of all reactants and products; design-forsafety; operation~ safety; safety management and

review. The deficiencies noted in the first pilot plant

effort have been addressed and the margin of safety

improved. However, whether the actions have been

sufficient can only be demonstrated by repeated

testing of the system.

Understanding the Physical and

Chemical Properties of Products and

Reactants

It is important to know as much as possible about

the physical and chemical properties of all the materials involved in a process and to understand the

thermodynamic and thermochemical properties of

all possible reactions. Of particular importance is

the amount of energy released during various reactions and the stability of the reactants and products in the presence of that energy. The physical

and chemical properties of DEZ, and its reactions

with other compounds have been studied for many

years. Texas Alkyls’ sales brochure for DEZ lists

some of these properties and reactions. Critical

safety information is available in the Product Safety

Information Data Sheet (see figure 21).

As mentioned DEZ is pyrophoric. The heat of

combustion is high. DEZ is also very reactive with

free hydrogen ions, hence its reactivity with acids

and water. These reactions are fairly well-understood. Stauffers (one of Texas Alkyls’ parent companies) has done some additional experiments with

liquid DEZ and liquid water reactions, measuring

the amount of ethane that is evolved.

According to tests performed by the Library,

DEZ does not react with most book materials. In

particular, the Library has concluded that DEZ
65

Figure 21 .—Product Safety Information Sheet for Diethylzinc

DIETHYLZINC (DEZ)

This Product Safety Information Sheet is principally

directed to managerial, safety, hygiene and medical

personnel. The description of physical, chemical and

toxicological properties and handling advice is based

on past experience. It is intended as a starting point for

the development of safety and health procedures.

This sheet gives information only for the pure form of

the chemical. Because the product is frequently sold in

solution, the physical properties and toxicology of the

particular solvent involved should also be considered

in developing safety and health procedures.

This product should not be used until personnel

handling it have been thoroughly trained. Contact

Texas Alkyls, Inc., c/o Stauffer Chemical Company,

Specialty Chemical Division, Westport, Connecticut

06880.

1. PHYSICAL AND CHEMICAL PROPERTIES

Chemical Formula: (C2H5)zZn

Molecular Weight 123.50

Physical State: Clear, colorless liquid

Melting Point: –300 C

Boiling Point: 117.6°C/760 mm Hg

Vapor Pressure: 15 mm Hg @ 20° C

Density: 1.198 g/ml @ 30° C

Viscosity: 0.7 centipoise @ 20” C

Flash Point: Pyrophoric — ignites spontaneously in air

Il. CHEMICAL REACTIVITY

Reacts violently with water, air and compounds containing active hydrogen. Ignites spontaneously on

contact with air. Compounds containing oxygen or

organic halide may react vigorously with the material.

Ill. STABILITY

Diethylzinc is stable when stored under an inert atmosphere and away from heat. Dry nitrogen is a suitable

hydrocarbons and elemental zinc when heated to

temperatures greater than 120° C, Caution—decomposition may be violent when temperatures exceed

150°C.

IV. FIRE HAZARD

Product is spontaneously flammable in air. Pyrophoric

by the paper char test* used to gauge pyrophoricity for

transportation.

V. FIREFIGHTING TECHNIQUE

Protecting against fire by strict adherence to safe operating procedures and proper equipment design is the

best way to minimize the possibility of fire damage.

Immediate action should be taken to confine the fire.

All lines and equipment which could contribute to the

fire should be shut off. The most effective fire extinguishing agent is dry chemical powder pressurized

with nitrogen. Sand, vermiculite or CO2 may be used.

Caution — reignition may occur.

DO NOT USE WATER, FOAM, CARBON TETRACHLORIDE OR CHLOROBROMOMETHANE extinguishing agents as product reacts violently or liberates

toxic fumes on contact with these agents.

A standard aluminized firefighting suit IS recommended for fighting large zinc alkyl fires.

Human exposure must be prevented and nonessential personnel evacuated from the immediate

area. Breathing vapors from zinc alkyl fires should be

avoided by using proper respiratory equipment.

NIOSH-MESA approved air-supplied full face respirator should be used.

VI. TOXICOLOGY

1. Hazardous Combustion Products

In the presence of air, the compound wiII combust

violently to form zinc oxide, CO2

, and water. Toxic irriinert gas. Diethylzinc decomposes evolving hydrogen, tants may result from incomplete combustion

In case of suspected DEZ exposure, refer to the procedure in Section VII —FIRST AID. Immediately

call, day and night, one of the following emergency contacts:

—Local Physician (Veterinarian, if animal exposure is suspected)

—Nearest Hospital or Poison Control Center

—Texas Alkyls, Inc. (Call Collect) (713) 479-8411

–Stauffer Chemical Company (Call Collect) (203) 226-6602

In case of spillage or contamination of other materials with the product, refer to Section IX —

HANDLING SPILLS and call:

–Texas Alkyls, Inc. (Call Collect) (713) 479-8411

–Stauffer Chemical Company (Call Collect) (203) 226-6602

–Chemtrec (800) 424-9300

“Reference W L Mudry, D C Burleson, D B Malpass, S C Watson, J. Fire and Flammabfhty, 6, 478 (1975)

All informatlon IS offered in good faith, without guarantee or obligation for the accuracy or EXCLUSIVE SALES AGENT:

sufficiency thereof, or the results obtained, and is accepted at user’s risk. The uses -

STAUFFER CHEMICAL COMPANY referred to are for the purpose of illustration only, user should investigate and establish the Specialty Chemical Division suitability of such use(s) in every case Nothing herein shall be construed as a recommendation

for uses which infringe valid patents or as extending a Iicense under valid patents Westport, Connecticut 06880

(203)222-3000

SOURCE Texas Alkyls, Inc
66

~fw-- 8@ceueeofttwh@hfy motive n@ure41ftht4GompoWd

with #r, ~k Mghtyunllkefy &eeSklncontact).

afnhaWon

eeoauaa of the MghtyraaotivanaturWft htaOmpound

with air, Wtafation of Ma Oompound fshightyuntikefy.

& $kfn contact

Concentrated product will react ifnmediatety with

mdature on the skin to prOdUCe aevem thermaf and

chemkat bum.

s Eya Contaat

Concentrated product will react immediately with

moisture in the eye to produce severe ahamkal and

thermat bums.

oombuatlon produow. Control of those inhalation

exposure can be achieved through the use of ● carWQO-WS NKW+MESA approved respirator.

asktncontaot

Oerma( expoaure must be moided through the use of

W retardant clothlng. Ourtngaampfing. disconnecting

lines or opening connections, additional protective

outerwear incfuding W faceahield, impervloua gloves.

aluminized Nomex coat a hard hat and chemkat safety

goggfe$ Shoutd @so be m.

4. #ye contact

Ourin$ sampling, diaconneothq lines or opaning connectkma, chamical 88f@y goggles and a futl face shicdd

should be worn.

6. ThmahoM Umft Vattte (TLQ

There la no TLV fortheproductbecauaehoompound lx~wSP&L$

does not etiiat in air. Wok off source of apill, extinguish fire with extinguishing agent-see Section V. Cautbn-Reignition

VU. PIRST AIO may occur. If fire cannot be oontrolted with axtinguishIf 8 known expoaum occurs, imm@atafy Wtiate tha Ing agent, k@8p 8 safo diatance, protect adjacent

recommended orooedurea betow. SMJttaneoualY PmP-’Y and aftow product to bum until Oonsumed.

Gontaof 8 $hyaiam Ouorlbe the type and extant tif

@w=Jf@ and eynwoma x, coRf@snftTY l’o ltiATmIAL$ OF coMsTRuoTlo@l

1. aye Contaot

lmmedi8toty flush the ayae with Wg4 quantittga of The pfoduct is not corroafve under inert conditions to

metals commonly ueed io running water for ● minimum of 15 mimHold the Oonatm@on. some plastics

eyetict$ *art 4&ring the Wr@tkmto enawlp ftwafhg ● nd elastomers may be attacked Texas A[kyla, {no.

Of th$ OJVth $Urf#O Of thO ~ and lid$ wfth W@tW’. 00 (713) 4?94411 or Stauffer Chemcal company, spenot attamot to nsutrab with chemioaf ~Obtain ciatty Chemioal 0ivi8ion {303) 223-3fWshould be conmedfcal @tentionaa soon .as posWtik We or oint- tacted for specific recommendatkma.

manta shoutd be used dyontheadvioeofaphyaichn. Xl. STORAGE REQUIRKMW14T8

Continuo tho kdgatim for an addttlonat WmMutaa if

the phyelcian is not immediatafy avu

Exerciaa due caution to @@vent damage or leakage of

%StKtn ContM

container. The produot ahdd be stored under an inert

Immedtataty remove oontamlnatad ofothi~ tinder ●

#tmoephereand away from heat See Sections Ill and X.

S8f.tY 8hOWOf. fluSh M ● ffeoted 8rWU ** Wge XIL OWOSAL OF w- MATERIAL

amountaof waterforst@aatWnMwt#h Oonot attwnfa Combustion of the matedd by oontrolllng feed of air

to neutraflza with @tamW agente! !f w is avdfabte, and produot is asuitabWfiaPO@Pmadwe. The Prod-

● pply locally to ttw Mooted afea. Obt8id nwdical

- ---& 4

uota from oompfete combustio n are carbon #oxide,

water ● nd aina oxido. Alternately, disposal can ba

SD tnhalatton achieved by dltuting tho product with hydrocarbon

Expoaute to combustion Produ@s may oau$a @WPire- (heptano, etc.) to Iea$ th&n 3 weight percent metal

tory symptoms. Rwnove from cofitm$n$td atmoaPWQ. lf We8thm has ceaqod, dear thevlothn% s4raikyl concentration and treating the hydrocarbon

soiution with water under ● nRrogen atmosphere In a

W*Y and staft moutMo-mo@I artifldet re$pWtOn, vented and agitated contaWter. Altowforthefpwratbn

whkh maybe supp@nwnted by the uaeofa -k of heat and flammable gaa whan traating with water.

respirator, or a manualtyW@#ed exy~ aupply The products from hydrolysis we othano and zinc

capablo ef delivering 1 Iiterheoonci or more. If tho oxide (hydrated). Oonduct water treatment in the

victim & breattdng, oxygen may beadminiatamdfrofn @ abaenoo of oxygan to avoid possible ignition of flamdomantf.t!me or continuou$-flow inh#*tor. ● nd mabte materM

prefmb&’Ath ● phyaioian’$ advice. Contact a phyStoian knrnadlawy. XIII* otsPosM ~f m~~-R$

VW. INWSTRIAL HVGtlKNS PRACllC@a Zinc! ● lky{ $hif@ngcontainW$ ● re returnable to

Texas AtkyK h., Deer Park, Texaa. Return ahipments

1. ~Pmct&aa of contairwr$ are to be made under 007 regulations.

Food $tm@d be kept in ctean designated arm B@fore

eating or conauming beverages, faceahd hatiahould

be thorouf)hly washed.

2 lnhat@On

This compound should be handled in welWefM4ted

areaa in order to minimize the potential expoaure to
67

does not significantly react with cellulose under

process conditions. Although cellulose has compounds with loosely held hydrogen ions attached

to it, some have hypothesized that the oxidation

of these compounds in air binds the hydrogen ions.

If there is any reaction with the DEZ, however, it

is very slow.

Most common metals used in equipment and

construction do not react with DEZ. In general,

metal alkyls are not corrosive and the original plants

at Texas Alkyls are still in operation. DEZ does,

however, degrade many elastomers used in gaskets

and seals. Texas Alkyls has developed over the years

numerous specifications for gaskets, seals, piping,

valves, etc. Other materials being used in the plant

that have not been specifed by Texas Alkyls have

been tested for compatibility by soaking samples

in DEZ at ambient conditions.

There are two critical physical properties of DEZ

which are not known that impact the design of the

hardware. One of these is the specific heat of DEZ.

The specific heat of a material determines the temperature changes that occur when the material is

expanded or compressed. DEZ vapor is expanded

and compressed a number of times during permeation. To ensure that DEZ does not get too hot during compression, pumping rates and pipe sizes must

be specified according to the specific heat of the material. Since this has not yet been determined, the

most conservative values, those for nitrogen gas,

have been used for design purposes. Early pilot

plant tests indicate that DEZ vapor temperatures

can be satisfactorily controlled.

Heat transfer properties of DEZ are also not

known. These properties are needed for designing

the condensers and vaporizer. Heat transfer values

for a typical hydrocarbon believed to behave similarly to DEZ were used for design. The actual

values for both heat transfer and for specific heat

will be determined during testing and incorporated

in the full-scale design.

Although the exothermic reactions are well-established, it is difficult to predict what changes in

temperature will occur in the books and the chamber during permeation. Heat will be generated in

the books from the reactions taking place, and other

possible causes. Attempts have been made to model

the amount of heat retained by the books, the

amount exchanged with the gases, and the amount

dissipated by the chamber, however, the results

have not agreed with the experimental data from

the previous NASA tests.

Design and operating conditions have been developed based on the maximum temperature increase observed in previous tests. Extensive instrumentation, a conservative temperature limit for

the system, and the ability to quickly introduce cool

nitrogen gas into the chamber should allow an

acceptable level of control of temperatures.

Also important is an understanding of the compatibility of various fire-fighting agents and techniques. Obviously, water as an extinguishing agent

would not be appropriate for fighting a DEZ fire.

DEZ fires are difficult to extinguish, however, reasonably effective techniques for controlling a DEZ

fire have been established. Fire associated with

small spills can be controlled by spreading dry

chemicals, sand, or vermiculite over the spill. This

prevents DEZ vapors from coming into contact with

the air. However, if the spill is disturbed, the

trapped vapors could escape and reignite. If the spill

is large, the fire is normally allowed to burn itself

out. If a large fire is in an area that threatens other

equipment, a fine water mist can be used to dissipate the heat of the fire, thus protecting nearby

equipment, storage tanks, etc.

Design for Safety

The Library has put together a competent design team for the second pilot plant. They have retained the full-time service of a chemical engineer

(consultant) who is responsible for overseeing the

design, construction, and operation of the plant on

a day-to-day basis.

The Library has contracted with Texas Alkyls

to design, construct, and operate the plant. Texas

Alkyls has been manufacturing metal alkyls since

1959, and DEZ for nearly as long. They have developed well-established specifications for materials for construction, hardware, etc.

The actual design and construction of the plant

has been subcontracted to S&B Engineering. S&B
68

Photo credit: Library of Congress

This double-block valve at Texas Alkyls pilot plant is

a key element in the safety system. It is controlled by

the computerized distributive control system (DCS).

has designed and constructed two other metal alkyl

plants for Texas Alkyls.

The principal safety-related design criteria for

the second pilot plant, and those which will probably be used for the full-scale plant as well, are:

●

●

●

●

●

●

A

tern

use a minimum amount of DEZ, and keep a

strict inventory;

keep DEZ in the system and air out of the

system;

prohibit liquid DEZ or liquid water from getting into the chamber, or from coming into

contact with each other anywhere else in the

system;

keep the temperature throughout the system

below 80° C;

use a computerized distributive control system

(DCS) to operate a series of safety interlocks;

and

design all lines and containment vessels for

both high and low pressure and provide proper

pressure relief mechanisms.

minimum amount of DEZ will be in the sysat any one time. Only the amount needed to

complete one batch treatment plus some reserve to

allow for variations in DEZ requirements will be

transferred from the liquid DEZ storage tank, located 15 feet from the plant, to a DEZ holding tank

inside the plant. The holding tank is separated from

all other plant systems by a fire wall. The DEZ is

vaporized and recycled continuously during

permeation.

To reduce the risk of component or line failures

and the subsequent release of DEZ to the atmosphere, well-established specifications developed over

the years by Texas Alkyls are used for materials

and construction. Wherever possible, reliable (and

tested) off-the-shelf pumps, valves, heat exchangers,

etc. are used. In cases where hardware may use materials not specified by Texas Alkyls, materials compatibility tests have been run, by exposing the materials to liquid DEZ for a few days and analyzing

for deleterious reactions.

The design deficiencies cited in the first pilot

plant accident report have been eliminated. Redundancies have been designed into the system to prevent either liquid DEZ or liquid water from getting into the chamber and to prevent water and

liquid DEZ from coming into contact with each

other anywhere in the system. The design of the

chamber was evaluated against a worst case scenario where liquid DEZ comes in contact with liquid water in the chamber. The design was reviewed

by two independent consultants to ensure that the

chamber could contain the resulting overpressure

and safely vent it to the atmosphere.

To ensure temperatures stay below 800 C, more

instrumentation has been added to monitor temperatures and pressures. The capability to circulate heated or cooled nitrogen gas through the

chamber has been added to better regulate book

temperatures during processing.

Operation of the pilot plant will be aided by a

computerized distributive control system (DC S).

The DCS will continuously monitor the entire system and manage a series of interlocks to ensure that

all operations are performed in the proper sequence

and under accepted conditions. If operations have

been performed out of sequence or if conditions in

the system are not acceptable, the DCS will not allow the process to proceed. The operator cannot

override the DCS without action from the shift supervisor. In an emergency situation, the DCS will

safely shut the system down. A backup electrical

supply will allow the DCS to safely shut the system down in the event of a power failure. Texas

Alkyls has gone as far as requiring a check for thunderstorms which may affect power supplies before

initiating the permeation stage of the process.
69

Should a spill, leak, or over pressure situation

arise, measures have been taken to isolate the hazard from personnel and from as much of the plant

as possible. Liquid DEZ is kept in one corner of

the processing area, behind a fire wall. The floor

is sloped to route any spills and fire away from the

processing area and other liquid DEZ vessels. Remote handling of the system will keep the operator isolated in a control room behind a fire wall and

away from any flares due to DEZ leaks. All lines

and containment vessels are equipped with pressure relief valves that will safely vent gases to the

outside environment. All pressure relief systems are

designed to National Fire Protection Association

codes.

Hazard alarms have been placed around the

plant to alert the operator to heat, fire, or explosion. Hand-held extinguishers are placed around

the plant for both electrical fires and DEZ-related

fires. Manually initiated sprinkler systems capable

of applying a fine mist of water have been installed

throughout the plant to help dissipate the heat from

any fire and protect personnel and surrounding

equipment. The sprinkler system is not activated

automatically, since it may not be the appropriate

response. The appropriate fire control action is left

to the judgment of the operator. The alarm systems, sprinkler system, and hand-held fire extinguishers have been designed in accordance with accepted National Fire Protection Association codes.

It has also been suggested by the Library’s outside safety specialists that (for the full-scale plant)

the building and the fire wall separating the chamber room from the control room be designed to

withstand an overpressure of 80 to 100 pounds per

square foot, in case of explosion.

Operational Safety

The safe operation of the system demands skilled

and experienced operators. These operators must

be thoroughly trained not only in the operation and

logic of the entire system, but also trained in the

hazards of DEZ, in general, safety and emergency

operations (including fire fighting and first aid),

housekeeping, and maintenance. The consequences

of a breakdown in operational safety are evident

in the first pilot plant accident.

The use of a computerized distributive control

system demands that the interaction between man

and computer is firmly established. This requires

a detailed operating manual that clearly spells out

the respective responsibilities of the operator and

the computer and extensive hands-on training.

Texas Alkyls brings over 20 years of expertise

to the operation of the pilot plant. Texas Alkyls has

developed safe and effective operating, inspection,

maintenance, housekeeping, and emergency procedures. They have reported only five loss time accidents since 1959. Furthermore, they have reassigned eight of their top operators to work on the

deacidification program. These operators have received 12 hours of training on the distributive control system as well as 11/2 months of training on

the total system during the commissioning of the

plant.

Safe operation of the DEZ system also requires

detailed operating procedures. The pilot plant operating manual was reviewed by OTA, as well as the

Library’s outside consultants. In general, the degree of detail was judged to be satisfactory, although

it was not yet complete at the time of the review.

The manual divides the 3 major steps of the process into 17 smaller, more detailed steps. Each step

contained a general description, a detailed set of

operations, which included the reason for each operation and appropriate precautions, a list of the permissive that must be met before initiating the step,

and a list of the various interlocking conditions

governing the step. The manual also contained the

startup and shutdown procedures and a general

description of emergency procedures. There was

some concern that the manual may be vague in certain areas, relying too much on the expertise already existing with the Texas Alkyls operators. If

this manual serves as the basis for the manual used

at the full-scale facility, it must be modified to apply to operation by personnel with less plant experience.

Safety Management and Review

Safety management and review is so important

that it must be considered at every stage of process

development— design, construction, and operation.
70

It is advisable, at the beginning of a development

program, to setup a distinct safety function within

the management of the program. This management

would be responsible and accountable for designing and implementing a safety plan. The plan

should establish what kind of safety analyses and

outside reviews are appropriate; schedule and conduct these analyses at the appropriate times; document the safety needs and requirements that come

out of the analyses; ensure that these needs and requirements are included in the design and specifications of the plant, hardware, and operation

manuals; and document the implementation of

these needs and requirements in the final construction and installation of equipment.

Analysis is a key element to a successful safety

program. There are a variety of safety analyses that

have been developed. They all incorporate the same

basic principles—identify the hazards associated

with the process or plant, determine the various

ways these hazards may come about and the consequences of them occuring, and determine the best

way to eliminate or reduce the chance or the consequences of them occurring.

The analyses, however, are of no practical use

if the results are not carried out. Documentation

and verification are critical.

The Library has made safety a distinct function

within the management of their program. The consulting project engineer has coordinated both inhouse and outside reviews, and has received reports

on the results.

The Library, Texas Alkyls, and S&B Engineering conducted an in-house ‘‘HAZOP’ review.

“HAZOP” was developed by DuPont Management Consulting Services to assist in identifying

and eliminating or minimizing the risks associated

with chemical processes. The review used piping

and instrumentation diagrams and examined them

line by line. For each line the following questions

were asked:

● What happens to the process as a whole if the

following deviations occur in this line?

—Flow—too high, too low, reversed?

—Pressure— too high, too low?

—Temperature —too high, too low?

—Concentration —too high, too low, Contaminant?

—Batch timing—too soon, too late, too short,

too long?

—Utilities—failure?

—Others—commissioning, maintenance?

Besides examining each line, each major piece of

hardware is also reviewed.

If any credible consequences were identified, the

process was examined for possible causes (including multiple failures), in the absence of protection.

If possible causes were identified, then the effectiveness of the existing protections were reviewed.

If the existing protections were considered inadequate, assignments were made to study the problem further and take appropriate action. This was

done before specifications, layouts, and procedures

are finalized to allow flexibility in solving problems.

The results of this review have been tabulated,

but the documentation could be improved. A number of possible events (or causes) are identified.

Associated with each event is a general description

of the existing protection, the necessary actions to

be taken and those responsible for taking the action. The actions to be taken were written in very

general terms, for example:

● action—DC logic (the distributive control system), or

● action—define operating procedures.

Before testing began, some of those who participated in the HAZOP exercise reviewed the various action items to ensure they were accomplished

satisfactorily y.

Outside Reviews

The Library has hired six outside consultants to

perform independent reviews in the following areas:

plant operability, pressure vessel design; vacuum

design; fire safety; and a worst case scenario. The

consultants reviewed the designs for the pilot plant

and those that exist for the commercial plant, before any hardware orders were placed. Written

reports were presented to the Library. Any differences in opinion were discussed and resolved by

consensus, although there is no documentation of
71

this. However, the Library did perform a second mented. The review was conducted by the same

outside safety review after the final construction of six outside consultants. Those with comments were

the pilot plant to verify that the various safety re- invited back a second time to review the implemenquirements and recommendations were imple- tation of their recommendations.

. .

SAFETY OF FULL-SCALE PLANT

Although a successful pilot plant program can

demonstrate the safety of the DEZ system, it cannot assure it. The safety of a full-scale plant will

depend on carrying forward all of the efforts and

expertise that have gone into the pilot plant program. In addition, the full-scale plant will introduce public safety concerns.

Transportation Issues

The transportation of liquid DEZ to the full-scale

plant will present a new set of risks to public safety.

The principal hazard is fire. Leaky valves, a common event in the transport and handling of tanks,

could cause DEZ vapors or liquid to be released

and ignited. There is also the threat of explosion

or rupture if the DEZ inside the tank disassociates.

A firey truck accident, also not uncommon, could

damage the relief valve and expose the tank to very

high temperatures. If gases evolved as a result of

rapid disassociation cannot be vented safely or

quickly enough, an explosion could occur.

During the course of a year, Texas Alkyls will

be trucking 15 to 20, 430-gallon tanks of neat liquid DEZ from their facility in Houston to the fullscale plant site. These will be individual shipments,

since the storage of DEZ at the plant site will be

kept to a minimum.

The 430-gallon tank will actually contain a nominal 390 gallons of DEZ, or 3,900 pounds. The tanks

are standard portable steel tanks, constructed in

accordance with DOT regulations (DOT CFR

178.245). They are designed to contain pressures up

to 200 psig. The DEZ will be shipped under low

pressure. The tank is fitted with a 45-psig relief

valve. The tank has a frame around it to facilitate

handling,

Texas Alkyls normally ships its DEZ diluted in

hexane. Although it is still pyrophoric, the hexane

acts as a heat sink, keeping the DEZ below its disassociation temperature. However, because it will

be shipping neat DEZ, Texas Alkyls has taken the

added precaution of insulating the tank with 4

inches of calcium silicate, and wrapping it in a stainless steel shield.

The insulated tank was designed with the help

of Stauffer Chemicals Research. The design criteria

was to limit the temperature rise of the DEZ in the

tank to less than 40 C when exposed to a standard

DOT bonfire test. The standard DOT bonfire test

exposes objects to a temperature of 870°C for 1/2

hour. A small test cylinder insulated with calcium

silicate was subjected to the bonfire test. The cylinder survived the test, the DEZ temperature inside the tank remained virtually unchanged and the

paint underneath the insulation showed no signs

of being affected by the heat. A similar uninsulated

cylinder of propane was tested along side the DEZ

cylinder and exploded. Calculations indicated that

the 430-gallon tank would require 2 inches of insulation, 4 inches were added as an additional safety

factor.
72

I

Incidents Involving the

Transportation of DEZ

All incidents associated with the transportation

of hazardous materials must be reported to DOT.

Since 1979, no incidents involving DEZ have been

reported. There have been five incidents involving metal alkyls. All involved relatively small

volumes. All were fire-related, resulting from faulty

valves or valve connections. No injuries were reported; losses totaling about $11,000 were attributed to the incidents.

These incidents apparently involve secondary

shipments of metal alkyls. There are no reports that

Texas Alkyls has had any incident involving the

transportation of its products. They ship their products in sizes ranging from one-liter vessels to railroad tank cars that can hold about 30,000 gallons.

Shipping Plans

The details concerning who and how DEZ will

be shipped to the full-scale plant have not been developed. Texas Alkyls contracts a commercial carrier to ship their products. Shipments are normally

made in in enclosed van. Normally, Texas Alkyls

only provides training to tank truck drivers. They

are given a demonstration of what a pyrophoric fire

is like, shown a film on the safe handling of DEZ,

and instructions on how to deal with local officials

in the case of an accident, If considered useful, this

training could also be made available to those enclosed van drivers shipping DEZ to the full-scale

plant.

During the testing at NASA-Goddard, the Library made preliminary contact with the fire marshalls at Fort Detrick and Frederick because of the

plans to locate the full-scale plant at the Fort. Discussions on a safe route from the interstate to the

site and fire control techniques were discussed. No

formal plans were developed. The Library also approached the Frederick City Council, where the

safety of the proposed shipments was debated.

These contacts were suspended after the NASAGoddard accident. If the Library locates the plant

at Fort Detrick, the Library intends to revive these

discussions sometime in 1989, possibly through the

Army Corps of Engineers.

Other Safety Issues Related to

the Full-Scale Operation

The decisions as to who will finally be responsible for designing, constructing, managing, and

operating the full-scale plant must still be made.

From a safety point of view it is imperative that

the effort that went into the Texas Alkyls’ pilot plant

be carried forward completely to the full-scale plant.

It is important that the contractor for the construction of the full-scale plant establish, as early

as possible, effective communication with Texas

Alkyls and S&B Engineering, who will have acquired the most experience with the process. It is

critical that the expertise of Texas Alkyls is transferred completely to the full-scale operation. It is

possible that the contract will go to Texas Alkyls.

RISKS

The transportation and use of DEZ poses risks the automatic sprinkler system would be located

to workers, the public, the plant, and books. These some distance away from the plant.

are discussed briefly in the following section. During a fire the risk is higher. The operator

must decide whether to use the sprinkler system or

Risk to Workers

not. There is an opportunity for an error in judgment. The fire or the intensity of heat can cause

Leaks or spills during operation pose a minimal injury if the choice has been made to control the

fire manually. Proper clothing and breathing de- risk to the worker if safe operations are followed.

Operation is remote and the operator sits behind vices as well as fire-fighting devices are needed.

a fire wall. Liquid DEZ is located in the far corner The greatest risk to workers occurs during mainof the plant. The fire control panel used to operate tenance. Detailed maintenance procedures and tests
73

are needed to reduce the chance of burns. Proper

clothing and breathing devices (for enclosed spaces)

are needed, and work should be done in teams. The

only injury recorded during the development of the

DEZ process was a worker at the G.E. test facility

that burned his arm when some DEZ mixture dripped on his skin from piping that he was cleaning.

The injury was minor, however, and did not require hospitalization.

There is some risk of injury or asphyxiation if

a person enters the chamber when the door to the

chamber is opened, since this is also a manual

operation.

Proper strengthening of walls, etc. should reduce

the risks associated with explosion for any enclosed

spaces.

Risk to Public

For the full-scale plant, the public is at some risk

due to the transportation of DEZ from Houston,

Truck accidents are the most frequent incident involving the release of hazardous materials. 2 Furthermore, the tipping or loss of portable tanks dur2U

. S. Congress, Oflicc of Technology Assessment, Transportation

of Hazardous Materials, OTA-SF,T-304 (Washington, DC: U. S, Go\ Icrnment Printing Officc, Jul} 1 986).

ing transit are a common mode of accident.

Nevertheless, fire during transit would be localized

and would not expose a large number of people to

the hazard. A more complete transportation risk

assessment could be included in the environmental

assessment yet to be completed for the full-scale

plant.

Risk to Plant

The plant is at greatest risk. Fire due to leaks

or spills are inevitable, even if the chances are kept

low by proper inspection and maintenance. The

types of fire that can be expected will be short in

duration but very hot and could cause extensive

damage. Damage can be controlled by keeping the

fire isolated and cool with an appropriately designed

sprinkler system, The

remote than fire, but

much greater.

Risk

The books remain

chance of explosion is more

the consequences could be

to Books

relatively safe. Fire in the

chamber is a very remote possibility, given the

redundancy in design, Excess zinc oxide deposition, although not necessarily harmful, may create visual problems. Wear and tear from book handling may also cause damage.

DISCUSSION

DEZ is a hazardous substance. Any system using consider some additional engineering problems.

DEZ is susceptible to fire and explosion. However, Safety practices will need to consider problems rewith proper design and operation, these hazards lated to a new site, new plant management, new

can be managed. operators, and a new community setting.

The second pilot plant has been built to good

OTA has qualitatively assessed the risks and feels chemical process engineering standards with careful attention to safety. OTA finds these efforts ade- the greatest risk is damage to the plant itself. The

quate, but the pilot plant tests during 1988 are greatest human risk is to plant workers during inineeded to demonstrate all safety aspects. As of Feb- tial hookup of the DEZ storage tank, maintenance,

ruary 1988, four initial commissioning runs of the or fire-fighting.

pilot plant have been completed in a safe manner There is a marginal risk to the public as a result and without incident.

of shipping DEZ. The Library must take extra preThe full-scale plant will need equal or greater caution to analyze that risk and work with the loengineering attention. Scale-up design will need to cal community in minimizing those risks.
Chapter 6

Health and Environmental Effects
CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . ..........”+.. . “””.++””.””””. .“o”o..””.”o

Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........*o..””” “.”.””s””+”o”””.0” ..”””

Health Effectsof Zinc and Zinc Oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Toxicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...........”+!”?”*o ““”””.”

Mutagenicity, Carcinogenicity, Teratogenicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Library’s Risk Assessment . . . . . . . . . . . . . . . . . . . . . + . . . . . . . . . . . ..”....””.”..””

Animal Study.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+++....”+’.”.”” ““”.”

Exposure Study . . . . . . . . .+....... . . . . . . . . . . . . . . . . . . . . . . . . . ....””.”+ ?+’”

Environmental Impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+.....”””.”~”””~””

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......””.”””. .“”””+”””+”.”

Tables

77

78

78

78

79

79

79

79

80

80

Table No. Page

14. Zinc Concentrations in the Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

15. Particle Size v. Respirability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

I

I
Chapter 6

Health and Environmental Effects

INTRODUCTION

As with any new process, there is a need to consider the human health and environmental impacts

of DEZ treatment of large quantities of books and

papers. The Library of Congress has begun a number of studies and intends to do further work prior

to building a full-scale treatment plant. This chapter

summarizes information about zinc, the health effects of zinc and zinc oxide, the Library risk assessment, and environmental impacts. Concerns about

the need for the Library’s risk assessment are presented in the Discussion section.

The compounds used and produced during the

DEZ process are DEZ, water, ethane, and zinc oxide. Although there is currently little evidence to

indicate that any of these compounds produce serious health effects, the Library is evaluating the risks

the process may pose to workers, librarians, and

library users. The Library’s effort focuses on zinc

oxide, which will be present as particles in the

treated books and as dust in the work environment.

Of particular concern is the inhalation of these zinc

oxide particles. The Library also plans to determine

whether any intermediate compounds are formed

during the process that would warrant toxicological investigation.

The biological contribution and health effects of

zinc and zinc compounds have been studied for

many years. Most of the literature relating to inhalation have focused on the effect acute or subchronic exposures have on respiratory function and

illness. There have been no tests studying the carcinogenic, teratogenic (birth defects), or reproductive effects of chronic zinc oxide inhalation, Therefore, the Library, with the help of two consulting

toxicologists, has designed an animal study to investigate these effects after chronic exposures to the

zinc oxide produced by the DEZ process. The results of these animal studies will be combined with

exposure measurements at the plant site and at the

Library to provide a complete risk assessment.

The other compounds associated with the process are not expected to pose any serious health problems. Ethane is considered to be a relatively benign compound. It is not considered carcinogenic

or mutagenic. It is, however, governed by the

OSHA limits on hydrocarbons, and can cause

asphyxiation in closed quarters.

DEZ is not considered to be a toxicological hazard, either. Its pyrophoric nature precludes exposure. However, dilute liquid mixtures of DEZ

can remain stable in air and cause severe burns if

it comes in contact with the eyes or skin. (See Risk

to Workers in previous chapter. ) The Library, in

an effort to test the toxicity of dilute gaseous mixtures of DEZ, exposed rats to hexane gas containing 20 percent DEZ by weight. The tests were inconclusive. Hexane itself is toxic, and rats exposed

just to hexane demonstrated similar behavior as

those exposed to the hexane-DEZ mixture. Autopsies showed no indication of growths or irritation

in either case. Unless there is any indication that

exposure to dilute concentrations of DEZ is a possibility, DEZ should not be a toxicological problem.

There have been two recent reviews of the literature on zinc and zinc oxide. The EPA Office of

Health and Environmental Assessment reviewed

the literature in 1987 in an effort to assist the Office of Air Quality Planning determine whether

these substances needed to be regulated as hazardous air pollutants. 1 They concluded that no regulations were needed. The literature was also reviewed by Leonard et al. in 1986.2 These two

reviews provided most of the following information.

1

0ffice of Health and Environmental Asscssm[. n t, U. S. Enf, ironmental Protection Agency, Summq, R rt’itw of’ Heal(h Efh.rs ,4ssociated with Zinc and Zinc Oxide: Health i.%su[. A.sst.,s.srncn(; August

1987,

2A Leonard, G. B. C,crbcr, and F. Leonard, ‘‘ Mutagenlclty, Carc inogcnic ity and TeratoScnicity of Zinc, Mutation Research 168:

343-353, 1986.

77
78

ZINC

Zinc is an important trace element in all living

organisms and in all tissues. It is found in the blood,

kidney, pancreas, liver, prostrate, skin, bone, and

eye. More than 20 zinc-containing proteins have

been identified, These proteins have both structural

and functional roles. Zinc enzymes assist in the synthesis of nucleic acids. Zinc also intervenes in a

number of physiological functions as well, including various immune responses, the metabolism of

hormones, and the stabilization of DNA’s double

helix, Zinc can also displace other metals. In the

case of cadmium, mercury, and lead, the displacement is beneficial. In the case of iron and copper,

the displacement has adverse effects.

Zinc is naturally found in small concentrations

in the environment (see table 14). There are many

manmade sources of zinc. These include metal mining, smelting, the production of zinc oxide and the

manufacture of products containing zinc oxide, and

Table 14.—Zinc Concentrations in the Environment

Soil. . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 to 300 ~glkg

Fresh water (unpolluted) . . . . . . . . . . Less than 10 ~glL

Surface water (polluted) . . . . . . . . . . .As high as 21 mg/L

Air (around zinc smelters) . . . . . . . . . Less than 1 ~glm3 to

15 ~g/m3

Air (around certain work sites) . . . . .As high as 18 ~g/m3

SOURCE: Environmental Protection Agency, 19S7.

the burning of refuse. Zinc is used for galvanizing

steel and in the production of rubber; and zinc oxide is used in pigments and in skin ointments, astringents, and antiseptics. Zinc oxide is also used

to coat Xerox papers and thus is present in many

office environments.

The zinc content of the average daily diet ranges

from 8 to 18 mg/kg. Most of this is from food and

drink. Intake through the skin or inhalation is minimal. The daily recommended allowance for adults

is 15 mg/day.

HEALTH EFFECTS OF ZINC AND ZINC OXIDE

Toxicity

There are no adverse effects associated with dermal exposures to zinc or zinc oxide. In fact, there

are many zinc compounds used for medicinal purposes, including zinc ointments for the healing of

wounds. Zinc compounds are found in baby powders. The Library conducted earlier toxicology tests

on rabbits, exposing them to papers treated by the

DEZ process. The results indicated that there was

no dermal toxicity.

Excessive or chronic oral ingestion of zinc can

cause some health effects. Long-term feeding of zinc

salts to rodents retarded growth, and led to anemia and metabolic effects. Excessive ingestion can

lead to anemia due to the displacement of iron.

There was some incidence of anemia attributed to

zinc ingestion in children who played with zinc cast

toys in alkaline bath waters. The effect can be

reversed with the consumption of iron. Ingestion

of zinc in excess of 400 ppm is known to cause gastrointestinal distress, including nausea and diarrhea. There have been recorded many incidence

of people experiencing these effects after consuming food or drink from galvanized containers. Longterm ingestion of excessive amount of zinc or zinc

oxide can cause immunological and cardiovascular effects. However, there is no evidence that

chronic ingestion of zinc is poisonous.

The acute inhalation of zinc or zinc oxide particles, on the order of O. 15 pm in size, can produce

adverse health effects known as ‘‘metal fume fever . It is normally associated with welding and

other zinc industrial environments. The symptoms

include fever, nausea, headaches, and dryness of

the mouth and throat. The effects are reversible in

24 to 48 hours. OSHA has set an acceptable exposure level at 5 mg/m3 for an 8-hour workday. Subchronic exposure to zinc oxide fumes, even somewhat below the OSHA level may cause gastrointestinal damage such as peptic ulcers and liver dysfunction and increased respiratory illness and

infection. Whether these effects can be expected

from working around the treated books or during

plant operation, depends on the particle size and

the amount of exposure. This will be discussed in

the section on exposure.
79

Mutagenicity, Carcinogenicity,

Teratogenicity

Zinc is not considered mutagenic, There is some

evidence that zinc acetate may cause chromosomal

aberrations in certain cells, but the cells that were

studied were not those normally used for studying

chromosomal damage.

There is no clinical evidence that indicates ingesting or inhaling zinc or zinc oxide causes tumors.

Examination of a variety of tumors show no correlation with zinc concentrations in the tissue. However, there have been no valid studies from which

to evaluate zinc’s carcinogenicity. Tumors have

been caused by repeatedly injecting the testicles of

birds and rodents with zinc salts. Zinc metal powder injected into the trachea of animals has also

produced tumors. In all of these cases, the tumors

were located at the site of injection. Injection is not

considered a valid exposure route and unless it

causes tumors away from the site of injection, it

is not considered a valid indication a substance’s

carcinogenicity.

Because of zinc’s role in DNA synthesis and cell

growth, zinc has been associated with promoting

the growth of certain tumors. In other cases, zinc

has inhibited tumor growth.

Zinc is not considered to be teratogenic. In fact,

zinc deficiency is known to be a major cause of birth

defects, and zinc can reverse the teratogenic effects

of cadmium. For this reason zinc supplements have

been given to pregnant women. However, there

have not been any teratogenic studies related to the

chronic inhalation of zinc oxide.

Excessive zinc has adversely affected fertility and

pregnancy in rats. The effect may or may not be

similar in humans. Normal levels of zinc do not

appear to be a problem. Pregnant women who have

been given zinc supplements, up to 81 mg/day during their final 3 months of pregnancy, have shown

no adverse effects.

LIBRARY’S RISK ASSESSMENT

Animal Study

The Library has designed an extensive animal

test to study what effects the acute (14 days), subchronic (91 days), and chronic (2 years) inhalation

of zinc oxide particles may have on pulmonary

function and male and female reproductive capabilities, and to determine the carcinogenicity and

teratogenicity of chronic inhalation of zinc oxide

particles. The study will expose rats to acute, subchronic, and chronic inhalation of zinc oxide particles at various concentrations in air, including a

zero percent zinc oxide control. Clinical and gross

pathologies will be performed on all specimens and

organs. Pulmonary physiology will be examined in

some specimens and pathology of the respiratory

track will be performed on all specimens, An examination of sperm morphology and vaginal cytology will also be performed on specimens in the

sub-chronic and chronic studies. Some specimens

from the sub-chronic exposures will be mated to

study the reproductive and teratogenic effects.

All tests will be performed in accordance with

the National Toxicological Program guidelines for

good laboratory practice.

Exposure Study

As part of its risk assessment, the Library is determining the particle size and levels of exposure

that can be expected for library users, librarians,

and process workers. Particle size will determine

how deep the particles may go into the lung (e. g.,

respirability). Particle size v. respirability is given

in table 15.

Library users can be expected to be exposed to

zinc oxide by leafing through a book. Two methods were used to determine the amount of zinc oxide to which a user may be exposed. One method

was to vacuum loose zinc oxide off randomly

selected pages of treated books. The other method

mechanically leafed through books and sampled the

air 5 inches above the pages.

Table 15.–Particle Size v. Respirability

Particle size @m) . . . . . . . . . 10 5 3.5 2.5 2

Percent respirable . . . . . . . . 0 25 50 75 100

SOURCE: Northrup Services Inc., “Evaluation of Diethylzinc-Treated Paper: Particulate Emissions,” Final Report to the Library of Congress, August

1985.
80

Librarian exposure will be determined by measuring the ambient air concentration of zinc oxide

in a simulated stack of treated books.

Worker exposure will be determined by taking

air samples at the chamber door, when the door

is opened and closed.

Results from the user exposure study indicated

that the particle or aggregated particle size averaged 0.6 to 1.5 μm by 0.4 to 1.0 pm. Particles of

this size are respirable, but 90 percent of those

measured were above the O. 15 μm particle size related to metal fume fever.3 In addition, the maximum airborne concentration, 5 inches above a me3Northrup Environmental Sciences, Triangle Park, NC, E~’afua -

tion of Dicthyl Zinc- Treated Paper: Particulate Emissions, a report

prepared for the Library of Congress, August 1985, p. 4-1.

chanically leafed book, was 0.06 μg/m3, well below

the OSHA acceptable limit. The concentration of

particles taken from the vacuumed pages ranged

from 9 million particles per cubic meter to 45 million. This is also below what would be considered

a toxic concentration of about 1 billion particles per

cubic meter. 4 Therefore, the exposure of Library

patrons to the zinc oxide in treated books should

not result in any known health effects. Whether or

not these concentrations will cause other health effects depends on the results and interpretation of

the animal study results.

The exposures of Library workers and plant

workers to zinc oxide have not yet been measured

at the time of this report.

‘Ibid., p, 4-2.

ENVIRONMENTAL IMPACT

In 1984 the Library prepared an initial environmental assessment of a proposed DEZ plant at Fort

Detrick. The purpose of the assessment was to determine to what extent the siting, construction, and

operation of the plant would impact the local surroundings and community. The assessment, based

on the scaled-up design of the first Goddard pilot

plant, determined there would be no significant impact. The assessment was reviewed and approved

by Fort Detrick personnel, but the accident at Goddard halted the process before it was presented to

the Army Corps of Engineers and the community

for review.

The Library intends to initiate a new environmental assessment after the full-scale plant design

is completed and a site has been selected. If the

plant remains at Fort Detrick, as originally planned,

a more comprehensive assessment than the first will

be required. If another site is chosen, a new, comprehensive assessment will probably be necessary.

Any ethane emissions will need to meet local air

pollution regulations. Other impacts will need to

be reviewed and evaluated for a new site. The Library must allow adequate time for environmental

assessment to avoid delaying the construction of the

plant.

DISCUSSION

OTA, with the assistance of consulting toxicologists, met with the Library’s consultants, to review the studies both completed and planned.

There was a general consensus that the search of

the existing literature was thorough, and that there

was a lack of studies directed at the effects of chronic

inhalation. The planned animal study designed by

the Library’s consultants was also considered to be

thorough and followed the accepted protocols.

There were, however, a couple of concerns expressed by OTA consultants.

There was some concern that the rat may not

be an appropriate model of the human respiratory

system. Rats have a greater clearance, i.e., can better remove particles from their lungs, than can humans. The amount of zinc oxide actually reaching

the rats lung (i. e., the actual dose) may be propor-
81

tionately far less than what would be expected to

reach a human’s lung. It was suggested that a prestudy test, measuring the clearance of various

models including the rat, could determine the most

appropriate model or at least determine the actual

amount of zinc oxide getting into the rats lungs.

There are some practical limitations to using

other animals too. The life span of other laboratory animals like rabbits or cats would make the

chronic exposures more expensive. Some animals’

lungs, such as the mouse’s lung, are not sensitive

enough for respiratory studies. Also there is a good

inhalation database for rats. The Library analyzed

this problem and concluded that it would be acceptable to use the rat model.

There was also some question as to the need for

the Library to perform evaluations on the chronic

effects of zinc oxide inhalation if the levels of exposure are below those experienced in the acute and

sub-chronic literature. Although there is no evidence to suggest that low levels of zinc oxide cause

chronic effects or is carcinogenic, this is not sufficient to say that there are no chronic effects or that

zinc oxide is not carcinogenic. Therefore, the Library and its consultants contend that it is in the

Library’s interest to perform a large-scale investigation into this area. It is not clear, however,

whether a single study can resolve the issue. Therefore, there is a question as to how much time and

effort the Library should spend in generating information that may have only a marginal value.

It was suggested by one of OTA’s consultants that

the Library perform the exposure analysis and determine whether the levels are comparable to or below those already studied in the literature. If they

are greater, then the rest of the study should be conducted. If they are below, then an extensive review

of the literature and the exposure study should

suffice.

Part II

Comparison of Alternatives for Book

Preservation and Deacidification
Chapter 7

Alternatives
CONTENTS

I

Introduction . . . . . . . . . .

Alternative. Processes. . .

Wei T’o . . . . . . . . . . .

Bookkeeper Process . .

Interleaf Vapor Phase Deacidification (VPD) . . . . . . . . . .

Advantages and Disadvantages of the Alternative Processes

Effectiveness . . . . t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

costs ... .$..****.* $* **~***********. ● **** *.. *sD***

Safety, Health, and Environmental Impact. . . . . . . . . . . .

Other Processes .. ... s 9 .....9... .. .. $ 0 . . . 0 . . . . . . . . .

Alkaline Paper Production ● O. ... .. O.. .O... . . . ..4....8.

Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

Advantages of Alkaline Paper to Paper Manufacturers . .

87

87

87

89

90

91

91

94

96

96

98

98

98

Disadvantages of Alkaline Paper to Paper Manufacturers. . ..................100

Discussion . . . . . . . . . . . . . . . . . . . . . . . .

Figure No.

22.

23.

24.

25.

Wei T’o Process . . . . . . . . . . . . . . .

Bookkeeper Process. s . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .***...* ...**... ● *$*. 101

Figures

Page

. . . . . . . . . . . .+.**.. . . . . . . . . . . . . . . . . ● ☛☛☛

✎☛✎✎✎✎✌ .,$..... ● *..**** ● +...... .*.*** *

Fold Endurance After Aging of Papers Treated by the Wei T’o Process. . . . . .

Estimates of Per-Book Costs for Deacidification by Various Processes, 1987 . .

Table No.

88

90

93

95

Page

16. Comparison of Alternative Mass Deacidifiication Processes, As of

January 1988 . . . . . . . . . . . . . . . .*...*,. .*.*...* ● *-****$ ● *-****” ● Qo”””*” ● 91

17. Accelerated Aging Effects on Fold Endurance of Treated and Un-Treated

Papers for the Bookkeeper Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

18. Capital Costs of Alternative Systems at Pilot Plant Sizes . . . . . . . . . . . . . . . ,.., 94

19. Selected Operating Costs for Three Systems at Pilot Plant Sizes . . . . . . . . . . . . 94
Chapter 7

Alternatives

INTRODUCTION

Part II of this report discusses possible alterna- tained information on, but was unable to thoroughly

tives to the Library’s proposed deacidification sys- analyze are identified in this section of the report.

tem. The main alternatives that are described are The potential for increasing the use of acid-free pathe Wei T’o, Bookkeeper (Koppers), and Interleaf per and what effect, if any, this might have on the

Vapor Phase Deacidification processes. Advantages Library’s program, is also discussed.

and disadvantages of these three main alternatives

to the Library’s DEZ process and an ideal deacidification system are discussed along with the effectiveness; costs; and impacts on safety, health, and

the environment.1

 Other processes that OTA obN.S. Hon. “An Evaluation of Mass Deacidiiication Processm for Book

of

‘ Separate cent ractor’s report to 01’.4 comparing the effect i~eness Presemation and a Comparison of Their Chemical Characteristics and

these pro{ ewes IS also a~ailable from OTA upon request: Da\’id Effectiveness, Clemson, SC, No\ember 1987.

ALTERNATIVE PROCESSES

Wei T'o

The mass deacidificiation process developed by

Wei T’o Associates is a nonaqueous liquid process that uses the same basic chemistry as the manual Wei T’o processes currently in use in many

libraries. A mass deacidification pilot plant was built

for the Canadian National Library and National

Archives in 1979. The plant was designed to treat

30 books at a time. Since 1981, the Canadian Library and Archives have been operating the system on a semi-production scale basis, treating about

120 to 150 books per 8-hour day. The Canadian

Library has no immediate plans to scale-up the

process. Wei T’o has a preliminary design and cost

assessment for a system that would double the batch

size and optimize the system’s throughput.

The Wei T’o process uses methoxy magnesium

methyl carbonate dissolved in methanol, and mixed

with Freon 12 and Freon 113. These freons are liquid gases, normally used as refrigerants, that allow the methoxy magnesium methyl carbonate/

methanol solution to penetrate into the paper.

Books are immersed in the solution and the

methoxy magnesium methyl carbonate reacts with

moisture in the books, theoretically forming magnesium carbonate, magnesium hydroxide, and

magnesium oxide. These compounds will react with

acids in the paper to form stable, neutral salts. Excess magnesium carbonate, hydroxide, and oxide

will join together to form a mixture (called basic

magnesium carbonate) that acts as the alkaline

buffer.

The system in place at the Canadian Library includes a warm air drier, a vacuum drier, and the

processing unit, which includes the processing chamber, a storage tank, and a recovery tank and condenser (see figure 22). The storage tank holds the

Wei T’o solution under pressure. To begin treatment, the solution is pumped through a filter to

remove impurities such as paper fragments loosened

from books into the processing chamber. After

treatment, the solution flows back into the storage

tank for reuse. Vapors from the chamber are evacuated and passed through a condenser and fed into

the receiving tank, which can then be sent back to

Wei T’o for reprocessing.

Selected books are placed in metal crates and

dried in warm air to remove a large amount of

moisture. Before being treated, the books are placed

in first one and then a second vacuum drier to reduce the books’ moisture content to 0.5 percent.

In the second vacuum drier the books are heated

87
r

88

Figure 22. - Wei T'o Process [Steps in Sequence O]

Evacuation - vapor line Recovered solvent vapor Recovery Aftercompressor cooler

I I

I I

Equalization line

I t

Purge air

Recirculation line

f Dram line

I

r---------- l

Pressure

regulating

valve and t

Filter

Fill line

u

Storage tank

w

Solvent

return

cylinder

SOURCE: R D Smith, “Mass Deactdification at the Public Archives of Canada;” Co nswwtion of Library andlldh?sl Materials and Graphk Arts; Guy Pethefbrige-.. (ad) (London:

Butterworth’s, 1967)
89

to about 1000 C and held there overnight at a pressure of 0.2 torr. The books must be dry to allow

good process control. Total drying time is about

24 hours.

The books are then transferred to the processing chamber. The chamber is bolted closed and a

vacuum pump evacuates the air and moisture from

the chamber. The books must be treated in a dry

environment because the solution will react with

excess moisture and turn into a gel. When the

chamber has been evacuated, it is backfilled with

vapors recycled from the receiving tank, equilibrating the process chamber pressure with the storage

tank pressure. This is done to avoid any turbulent

flow when the solution is fed from the storage tank

into the process chamber. The solution is introduced slowly to avoid forming any bubbles that may

result in non-uniform impregnation of the books.

Once the chamber is filled, it is stabilized for 4 minutes and then more solution is added to increase

the pressure in the chamber. The chamber is left

under pressure for roughly 40 minutes to allow adequate penetration of the solution into the books’

pages.

When the treatment is completed, the solution

is drained back into the storage tank, After the

chamber has been completely drained, a vacuum

pump removes all the excess vapors, routes them

through a condenser, and the liquid is stored in the

receiving tank. This removes a large fraction of the

excess solution and freon left in the books. The

chamber is then purged with warm air and opened.

The crates are removed and placed in a storage cabinet overnight, where the remaining solution and

freon evaporates until the books warm up and regain a portion of their original moisture content.

They regain the rest of their moisture slowly after

leaving treatment.

The chemical treatment step takes about 1 hour.

This includes the time it takes to pull another

vacuum on the chamber after the books have been

removed to minimize the amount of vapors left in

the chamber and eliminate fouling of the chamber.

Total cycle time is roughly 26 hours plus the cabinet storage time after treatment. The Canadian

plant treats about four to five batches of 30 books

each per 8-hour day with two operators for the entire plant or about 42,000 books per year.

Bookkeeper Process

The ‘ ‘Bookkeeper” process is a nonaqueous liquid process that was initially developed by the Koppers Chemical Co. beginning in 1981. Development progressed to a detailed design of a pilot

facility capable of treating 100 books per day. An

agreement was negotiated between Koppers and

The University of California at Berkeley to construct and demonstrate the pilot system at the

university. Koppers halted the project, however,

after they concluded that the Library of Congress

was committed to the DEZ process and that the private library business potential was too limited. Koppers has since sold the patent to Richard Spatz, who

recently retired from Koppers. In 1987 Mr. Spatz

contracted with Koppers to have the original development team continue work to improve the system under the name ‘ ‘Bookkeeper.

The “Bookkeeper” process uses a suspension of

fine (submicron) particles of magnesium oxide dispersed in a fluorocarbon (e.g., Freon 113) and a

surfactant. No solvents such as methanol are used,

The fluorocarbon carries the particles into the paper and the surfactants keep the particles evenly

dispersed in the mixture. The process does not immediately neutralize the acids present in the paper. Rather, when the books are immersed in the

mixture, the magnesium oxide particles are implanted into the paper and deacidification occurs

later as the acids migrate to and react with the particles over time.

The process is capable of being designed as either a batch or a continuous process. The pilot plant

was designed as a batch process and designed to

fit in a tractor trailer. It consisted of storage/mixing tanks, a loading area, a treatment tank, and

a drier/condenser. (See figure 23, )

Books do not have to be predried in this process. Books (current designs hold three books) are

loaded into a fixture that spreads the books open

to a specified angle. The fixture is then lowered into

the treatment tank and the tank is filled with the

mixture. The fixture is then mechanically agitated

while the mixture is circulated to ensure complete

wetting of the book and its pages. The fixture is

designed to close the books before they are removed

from the tank. Treatment takes only a few min-
Figure 23.-Bookkeeper Process

i , 1

r

system

T

Steam

tank tank tank tank

+ + + I

pump pump pump

SOURCE: ~ad from a Koppem Diagmm

utes. The books are then removed from the fixture

and placed in an air drier. The vapors from the

drier are condensed and recycled. Total process

time is 4 to 5 hours.

Experiments are currently being performed that

place a book fixture, holding about 10 books, in

a processing chamber similar to the kind used in

the Wei T’o process. The chamber is then filled

with the mixture and the books agitated. After the

chamber is drained, it is evacuated by a vacuum

pump for about 1 hour to evaporate the majority

(about 95 percent) of the mixture remaining in the

books. Warm freon vapors are then passed through

coils in the chamber and the remaining 5 percent

of the mixture remaining in the books after treatment is evaporated under vacuum. In this new development, total cycle time may be about 3 hours.

Interleaf Vapor Phase Deacidification

(VPD)

The Interleaf process is a vapor phase deacidification process developed in England by Langwell

in the 1960s. The patents to the product have been

purchased by B.G. Robertson Laboratories. Interleaf, Inc. of Minneapolis is the sole U.S. distributor.

The VPD process uses cyclohexylamine carbonate crystals that are either impregnated on a

sheet of paper or placed in a packet that is then

placed between the pages of the books to be deacidified. Cyclohexylamine carbonate is a organic

derivative of ammonia and is volatile at room temperature. The crystals release vapors that neutralize acids as they permeate through the pages of the

book. Placing the packets takes only a few minutes

and complete book deacidification is achieved slowly

over several days.

The technique is being used at the Public

Records Office in London and the United Nations

in Geneva. In this country, Interleaf offers this service to customers that are having books rebound and

sells the packets to the general public. The largest

deacidification project that Interleaf has done involves the deacidification of 1,200 to 1,500 books

from a small law book collection. Books are treated

in batches of 100 and placed in boxes for 10 to 12

days and then removed.
91

ADVANTAGES AND DISADVANTAGES OF

THE ALTERNATIVE PROCESSES

It is not possible to make a definitive comparison of the various processes at this time. Data

assessing the effectiveness of the processes are

limited and those that do exist do not fully assess

the processes’ effect on paper. Nor have any of the

processes been developed enough to allow for an

accurate assessment of the potential treatment capacities or costs. However, for DEZ and three major alternatives, OTA has made qualitative comparisons of process effectiveness; capacities and

costs; and safety, health, and environmental impacts. The results of these comparisons, against an

ideal system, are shown in table 16.

Effectiveness

There is a general lack of meaningful data to

compare the effectiveness of the various processes.

The effects the various treatments have on the

chemical properties and behavior of the various

chemical components of paper— including cellulose and its hydroxyl and carbonyl functional

groups, hemicellulose, and lignin—have not been

given much attention. Data on the effect of treatment on optical properties of paper are also limited.

Nor has the stability of treated papers to light, pollution, and other degradation mechanisms been

properly evaluated. The effects various treatments

have on mechanical properties have received the

most attention, but the results that have been reported are not conclusive. The change in the degree of polymerization, which some paper chemists

feel is a more definitive measure of a process’ effectiveness, has not been measured.

The data that do exist have been generated over

a long period of time by the individual developers,

on different types of papers, under a variety of test

conditions, measuring only a few of the important

properties. Ideally, a definitive assessment would

require a direct comparison of paper specimens

treated by the various processes and tested under

identical conditions.

Nevertheless, OTA has made a qualitative comparison of the effectiveness of the various processes

(shown in table 16) based on the following criteria:

● the need for preelection (i. e., screening) and

predrying before treatment;

● cycle times ;

● complexity of the treatment plant;

Table 16.—Comparison of Alternative Mass Deacidification Processes, As of January 1988

Criteria Ideal DEZa Wei T’o Bookkeeperb

VPDC

Preelection of books . . . . . No No Yes Minimal d

Yes

Predrying . . . . . . . . . . . . . . . . None Yes Yes None None

Impregnation time. . . . . . . . .Short Long Short Short Very long

Treatment plant . . . . . . . . . . . Simple Complex Less complex Simple Very simple

Effect on inks and colors . . None None Some Minimal d

Some

Effect on plastic covers . . . . No No Yes Minimal d

Yes

Neutralization. . . . . . . . . . . . .Complete Complete Needs verification Needs verification Partial

pH of treated paper . ......7.0-8.5 7.0-7.5 8.5-9.5e

8.0-9.0e (surface) 5.0-8.7

Alkaline reserve. . . . . . . . . . .About 2% 1.5-2,0°/0 0.7-0 .8 %

e 2 %

e

None

Danger to health . . . . . . . . . . None Risk of fire Uncertainf Uncertain f Uncertain

Impact on environment . . . . None Low Uncertaing Uncertaing

Low

Stage of development . . . . . — Operating pilot plant Operating pilot plant Lab tested pilot Commercial

(2 me.) (7 years) design

cost . . . . . . . . . . . . . . . . . . . . . – Moderate to highh

Low to moderateh

Lowh

Lowh

aLibraw of Congre991 DEZ Process.

~41Bookkeepr’1 SUbmicron particle process.

CLangWell vapor phase deacidification process—distributed by Interleaf, Inc.

dBas~ on telephone conversation with Dr. J.J. Kozak of Koppers (Nov. 2, 1987). No independent assessment.

eNo formal independent analy9e9 have been made, Manufacturers data indicates complete neutralization Under laboratory conditions.

flnitial indications are good but no formal assessments have been made.

gsome concern about the future regulation of fluorocarbons used in these processes.

hBased on OTA analysis and extrapolation of limited cost data furnished by developer of each sYstem.

SOURCE: David Hen, “An Evaluation of Mass Deacidification Processes for Book Preservation and a Comparison of Their Chemical Characteristics and Effectiveness,”

prepared for OTA, November 1987.
●

●

●

●

●

●

effect on inks and colors, plastic book covers

and other materials;

completeness of neutralization and pH after

treatment;

amount of alkaline reserve after treatment;

impacts on health and environment;

stage of development; and

cost .

In small-scale tests the DEZ process can, very

impressively, neutralize all excess acids in the paper and deposit a uniform alkaline buffer. Deacidification byproducts are neutral and stable. An advantage of the DEZ process over all the others is that

the initial deacidification occurs independently of

the alkaline buffer deposition. As a result, all papers

are left nearly neutral after treatment, no matter

what their original acid contents may have been.

Furthermore, the amount of alkaline buffer depos-

‘ ited can be controlled to a much greater extent and

achieve a greater uniformity within a book. However, the uniformity and completeness of treatment

from book to book depends on the flow characteristics of the gases in the chamber and the characteristics of papers in the books. Whether very uniform results can be achieved routinely in a full-scale

operation must still be demonstrated.

Based on process tests to date, preelection for

the DEZ treatment will probably not be needed.

The DEZ treatment appears to be compatible with

most other book materials including inks, colors,

and pigments. It may cause some loss of brightness in nitrocellulose covers. The problem of excess zinc oxide deposits on book covers can be minimized, but depends on the flow of gases in the

chamber. The DEZ treatment may leave a slight

odor immediately after treatment.

The zinc oxide buffer could increase paper’s sensitivity to photodegradation. This is of concern to

the Library and they are planning further tests.

Some other long-term effects must also be studied

further: such as the effect of DEZ/nitro-cellulose

reactions. The Library claims that the DEZ process can extend the life of a book three to five times

based on fold endurance of test papers. The data

that have been presented to support this have not

been presented conclusively for the actual books in

the Library’s collection. Such an evaluation is

planned as part of the quality control program that

will be developed and tested at the Texas Alkyls

pilot plant.

The Wei T’o plant is simpler than the DEZ plant

and its chemistry is generally accepted within the

preservation community. There is little data, however, on the uniformity of treatment in a mass deacidification system. An examination of one of the

books treated when OTA visited the Canadian facility indicated that there were spotty areas where

the pages had not been deacidified. Whether this

was an isolated case that could be remedied by adjusting the solution concentration or adjusting the

process parameters is not known. The alkaline buffer deposited is comparatively small relative to the

other processes. The plant also does not appear to

have been subjected to a systematic quality control program and no process test results are

available.

The Wei T’o process requires pre-inspection of

all books about to be treated. The solvents used in

the process are known to cause certain colors to

transfer and certain inks to run. Experienced operators can determine which books may be affected

by simple inspection. With inexperienced operators or when encountering unfamiliar papers and

colors, the particular pages must be tested to determine what effect the process may have. Some

books cannot be treated at all, others can be treated

after placing blank paper between the color pages.

Because of its relatively high alkalinity, the Wei T’o

process can also cause discoloration after treatment

if the paper is exposed to high humidity or water.

Certain plastic covers will crack and flake. The reason for this is not known. It may be related to the

difference in thermal expansion between the plastic coating and the paper cover. The books cool

quickly as the freon and methanol evaporate from

the books after treatment. The process does not

leave any odor in the books. These various constraints cause rejection of about 20 to 25 percent

of the books submitted for treatment.

According to its President, Wei T’o is developing new chemicals for its processes. He claims that

new non-alcoholic solvents are being developed to

eliminate the problems of color transfer and ink

swelling, and that magnesium will be replaced in

the deacidifying agent to lower the alkalinity of the

treated paper and reduce the problems of discol-
93

oration. The status of these new developments is

not known.

The long-term effect of the Wei T’o process on

various paper properties has not been adequately

studied. There is limited published evidence that

the mass deacidification system now in use extends

the life of books. Some fold endurance test results

are shown in figure 24. While improvements in the

papers are evident, the description of test conditions and test data is not sufficient for an evaluation of the significance of results.

Figure 24. -Fold Endurance After Aging of Papers

Treated by the Wei T’o Process

2.2

2.0

1.8

.,6 L

\

\ \

0.6 –

0.4 ‘ ➤

\

0.2 –

\

0.0

0 3 6 9 12 15

Days of dry heat aging at IO@ C

D ---- Untreate d K ---- Untreate d

E — Treate d L — Treate d

F ---- Untreate d N ---- Untreate d

G — Treated M — Treated

SOURCE: R D Smdh, b~mtino(Libm~adtiW/Mewa/s and Grap/rk

Ms; “Mass Deacldlflcatlon at the Public ArchIves of Canada,” Guy

Petherbndge (ad ) (London: Buttewcxth’s, 1987)

The Bookkeeper process can achieve a uniform

deposition of magnesium oxide throughout the

pages of a book. Tests of this have been based on

x-ray diffraction analysis and scanning electron

microscopy. The treatment can also effectively neutralize acids, raising the pH of papers up to 8 or

9. Tests by the developer have shown that fanning

the pages of bound volumes is necessary to assure

complete treatment and uniform pH values from

outer edges to the binding. However, only surface

analyses have been performed. Cold extraction pH

measurements have not been made. Since total deacidification depends on the original amount of

magnesium oxide that gets deposited, it is important to know how much buffer is left to inhibit reacidification. The Bookkeeper developer has done

an initial microscopic study of treated paper which

shows evidence of some penetration of magnesium

oxide particles, but a more extensive test program

is needed.2 If the process proved not to completely

deacidify the interior of papers, it would be a serious drawback to its use.

The Bookkeeper process is the simplest of the

mass deacidification systems and may require the

shortest cycle time.

The Bookkeeper process may require little preelection, but the effects of the treatment on paper

and other book materials has not yet been adequately studied. Because of the chemicals used in

the Bookkeeper process, certain problems associated with color transfer and ink swelling should not

be expected. The problem with certain plasticcovered books may present a similar problem for

the Bookkeeper process as it does to the Wei T’o

process, since it too uses freon that will quickly

evaporate after treatment. The process does not

leave an odor in the treated books.

As with the other processes the long-term effects

of the treatment on the life and other properties of

paper have not been adequately studied. Some fold

endurance tests have been conducted, and the results are comparable to those for both the DEZ and

Wei T’o processes. (See table 17. ) Based on this

limited data, Bookkeeper claims that the life of a

book can be extended two to three times.3

‘Letter from Richard E. Spatz with enclosures, Dec. 29, 1987.

‘Kundrot Patent, U.S. Patent No, 4,522,843, Jan, 11, 1985, p. 5.
9 4

Table 17.–Accelerated Aging Effects on Fold

Endurance of Treated and Un-Treated Papers

for the Bookkeeper Process

(aging conditions–70 ‘C, saturated R. H.)

Fold endurance

(double fold with 0.5 kg)

Days of exposure Untreated Treated

o . . . . . . . . . . . . . . . . . . . . . . 1,406 1,390

7 933 1,160

14:::::::::::::::::::: : : 619 969

21 . . . . . . . . . . . . . . . . . . . . . . 410 809

28 . . . . . . . . . . . . . . . . . . . . . . 272 676

SOURCE: Bookkeepw.

The VPD process is the simplest of all the processes but cannot really be considered a mass deacidification in the same scale as the other three systerns. The VPD process does not deposit an alkaline

buffer. Protection lasts only as long as the packets

continue to give off vapors. The deacidification may

not be permanent since the byproducts are volatile and under certain conditions (i.e., humidity and

temperature) may revert back to acids. The data

relating to the uniformity and completeness of treatment is anecdotal.

Cyclohexylamine carbonate will react with some

inks, colors, and plastic covers, and therefore will

require preelection before treating. Cyclohexylamine carbonate will also leave an odor in the books.

The use of charcoal in the packets reduces the odor

only slightly.

costs

It is difficult to obtain uniform cost estimates for

comparing the various processes. Most of the

detailed estimates have been independently prepared by the developers of each process and certain major cost categories are not always included.

Three types of costs are important: first, the capital cost of a facility to treat a certain number of

books; second, facility operating costs per unit time

(usually 1 year); finally, per-book costs with assumptions of the total number of books treated per

year. These three cost types are presented separately. Because most of the data are available for

pilot plant sizes (about 40,000 books per year), cost

comparisons will be made only for this capacity.

Capital Costs

OTA has obtained pilot plant capital cost estimates for three processes (DEZ, Wei T’o, and

Bookkeeper) from the developers of that process.

(See table 18.) Conveniently, roughly similar capacity pilot plants have been designed or built for

each.

Operating Costs

To compare operating costs, all important categories for each process must be considered. Since

only some of the data are available from developers

of each system, OTA made rough estimates of some

missing items. Table 19 displays certain operating

Table 18.—Capital Costs of Alternative Systems

at Pilot Plant Sizes

cost Books

Pilot plant ($ millions) capacity/18-hr. shift

DEZa

50

Design . . . . . . . . . . . . . . . 0.6

Construction. . . . . . . . . . 1.3

Wei T’ob

(no design breakout) . . . 0.5 150

Bookkeeper c

(construction only) . . . . 0.4-0.6 100

.SB~ed on the ~tu~ cost Of design and construction for the pilot plmt @Texas

Alkyls; capacity based on 55-hour cycle time may be modified depending on

experiments to be performed during 19SS.

bBaSed rjn actual costs In 1979 reported to OTA by Canadian National Archives.

Other information Indicates this may also be approximately the replacement

cost in 19S7.

cBased on Bookkeeper design and detailed cost estimate reported to OTA In

October 19S7. A modification to the design in December 1987 (a closed chamber

system) was reported by the manufacturer to have a lower cost.

SOURCE: Office of Technology Assessment, 19SS.

Table 19.—Selected Operating Costs for Three

Systems at Pilot Plant Sizes

(thousands of dollars per year)

D E Z

a Wei T’ob Bookkeepe r

Plant costs . . . . . . . . . . . . . 50 100 30

Operating labor . ........120 80 80

Overhead and

administration . . . . . . . . 30 20 20

Total. . .............200 200 130

aproratsd from Library of Congress estimates for full-scale Plant.

bFrom carl@m experience.

CFrOnl Richard Spatz estimates for plant costs and Canadian experience for other

costs.

SOURCE: Office of Technology Assessment, 1988.
95

costs per year for the same pilot plant treatment

capacities noted above (assume 40,000 books per

year). Operating costs associated with transportation and handling of books to and from a treatment

facility are not included because these costs can vary

significantly depending on the library and the plant

location as well as setup.

Per-Book Costs

Figure 25 displays deacidification costs per book

from OTA estimates based on a variety of sources.

perience are shown as single values; those based

upon projections as +/- 20-percent range. It is clear

that there are a wide range of costs for the various

processes. For the 40,000 book per year pilot plant

size, present indications are that the DEZ process

is by far the highest cost followed by Wei-To, Bookkeeper, and Interleaf (VPD).4 Further design, development and testing could change these costs—

especially for DEZ and Bookkeeper. The much

larger plants, of course, are more uncertain for final costs. Even with this uncertainty, it does apOTA tried to make all costs comparable by add- 4The cost for the VPD process is based on information from the

ing similar figures for categories not supplied by manufacturer of a typical charge he has made in the past for treating

others. Those costs based upon some operating ex- a few thousand books at his facility.

Figure 25. -Estlmates of Per-Book Costs for Deacidification by Various Processes, 1987

I I

$15 ------ - Princeton-Wei To Spray @ 1,000/yr

---- Austrian Lib. @ 3,000/yr

$14

$13

$12

$11

I I

‘ --- DEZ Pilot Plant

$10

$9 Wei T'o-Canada

$7 -

$6 –

$5 -

$4 –

$3 –

$2 –

$1 –

0-- Interfeaf 1

Congress

1986

estimate

I

- -

I

1 \

------ -

I

f

I

I

I

/’

o h

estimate of

full scale

DEZ plant

I I 1 I 1 I I I I

I

L I I I I I I I 1 I

100 400 500 700 1,000

Thousands of books per year

SOURCE: Office of Technology Assessment, 1988
pear that the DEZ process will remain the highest

cost alternative.

Safety, Health, and Environmental

Impact

The DEZ process does pose safety risks to the

plant worker and the public. The reactivity and instability of DEZ expose the workers and the public to potential fire. The impact on health is not expected to be serious. The Library has performed

a lengthy review of the health effects literature for

zinc oxide and has performed a number of toxicological tests. It is also about to perform an extensive animal study to assess the risks of carcinogenicity and other health effects not documented in

the literature.

Although neither the Wei T’o or the Bookkeeper

process appear to pose serious safety hazards nor

adverse health effects, no formal assessments or

literature reviews have been made. Therefore,

OTA also lists their impact on health as uncertain

in table 16. Fluorocarbons, used in both of these

systems, can cause asphyxiation and, if decomposed, can release toxic gases. The amount of Freon

12 in the work environment at the Candanian Wei

T’o facility was measured and was well below the

Threshold Limit Value (TLV) set for freon. Workplace concentrations averaged from 63 to 125 ppm

per volume. The TLV is 1,000 ppm per volume.5

Because of the uncertainty regarding future regulations on the use of fluorocarbons, the cost and

complexity of both the Wei T’o and the Bookkeeper

processes may increase. The fluorocarbons used in

these processes can be replaced by other compounds,

but both effectiveness and safety may be compromised. Substitutes with similar properties are flammable and more reactive. Ethane emissions from

the DEZ process should meet existing hydrocarbon

regulations. Ethane’s contribution to smog and

other air pollution is relatively small and will probably not be affected by any changes in these regulations.

The VPD process is a manual process and poses

no safety hazards. Early in its development, however, concerns about the carcinogenicity of cycla5J. M. Elgie, Dupont of Canada, Ltd., Technical Report Prepared

for the National Archives of Canada, Apr. 2, 1980.

mates were extended to cyclohexylamines. These

concerns have been relaxed. The use of cyclohexylamines as rust inhibitors is extensive in England.G

However, as with the Wei T’o and the Bookkeeper

processes, no formal assessment of cyclohexylamines or the VPD process has been made. Therefore, its effect on health is also listed as uncertain

in table 16.

Other Processes

OTA received limited information on several

other deacidification and combined deacidification/strengthening processes. The information provided was either insufficient to analyze to the same

degree as the other systems discussed, or the development of the process has not progressed far

enough to be considered a viable alternative to the

Library’s DEZ process.

Deacidification Processes

The French process developed by the Bibliotheque Nationale uses essentially the same chemistry as the Wei T’o system. A pilot-scale plant began operation at the Conservation Center at

Chateau de Sable during the fall of 1987 with a capacity of 300 books per 8-hour shift. The system

has been described as using more solvents than the

Canadian system, which may result in problems

with certain inks running. 7 The Bibliotheque Nationale plant is still in its trial period as of this writing, but the developers report analyses show uniform treatment and good alkaline reserve, The

developers also plan to conduct their own evaluation during 1988.8

The Kathpalia process uses ammonia in a sealed

chamber. The process has been used in India by

the National Library and National Archives as early

as 1955. Current costs are about 30 cents per volume that is 4 inches thick in a chamber that holds

350 volumes. g Major criticisms of this system are

‘Personal communication with a Robertson lab representative.

J

7 can-Marie Arnault, “Mass Deacidification in France, ” paper presented at the Preservation of Library Materials Conference sponsored

by CDNL, with the cooperation of IFLA and UNESCO, Vienna,

April 1986, referenced in G. M. Cunha, Mass Deacidification for

Libraries, Library Technology Reports, May-June 1987, p. 383.

8Jean-Marie Arnoult, Bibliotheque Nationale, letter to Peter Johnson, Nov. 16, 1987.

‘Yashpal Kathpalia letter to Peter Johnson, Dec. 12, 1987.
9 7

that it does not provide an alkaline reserve and bad

odors are associated with the process. Kathpalia

responds to these criticisms by stating that a reserve

is not really needed if the books are stored properly and even if they do need to be retreated, the

process is so inexpensive it is not a problem. He

also responds that odors can be eliminated with adequate ventilation. OTA has not examined this process in detail, but conventional wisdom is skeptical

of amine-based processes. Detailed evaluations of

the current condition of books that were treated

with this process back in the 1950s might be enlightening.

Combined Deacidification/

Strengthening Processes

The Austrian National Library is currently deacidifying and strengthening its newspaper collection. The process it has developed is an adaption

of the aqueous deacidification process using calcium

hydroxide as the neutralizing and buffering agent.

In addition, methyl cellulose is added to the solution. The methyl cellulose precipitates out of solution and acts as a laminate to strengthen the paper. After removing the cover, a block of newspapers

is immersed in the solution and then shock frozen

at –40 0 C. The frozen block of paper is then

freeze-dried and rebound. The Austrian Library

is treating about 50 blocks of newspapers per 5-day

week. 10

The German Library in Leipzig is also developing a process based on the aqueous calcium

hydroxide solution deacidification system. The German process adds a carrier to the solution that deposits new cotton cellulose fibers, actually putting

a new layer of paper over the old.

The British Library is developing a process that

would strengthen paper by grafting a polymer onto

the paper’s cellulose chains. Papers are exposed to

a monomer mixture that impregnates the paper.

The paper is then irradiated with low-intensity

gamma rays, causing the monomer to attach to the

cellulose and to polymerize into chains that link with

other cellulose fibers. 11 The process can also be used

to deposit an alkaline buffer by choosing an appropriate base monomer as co-monomer. The British

process is entering engineering development. Current work is focused on a liquid system. After this

has been refined, a large-scale system is planned

that could treat 100,000 to 200,000 books per year

at a preliminary cost estimate of $5 per book. 12 Recent developments on this process were presented

by Dr. Clements in a paper titled “Emerging Technologies in Paper Strengthening: Development and

Scale-Up of Graft Co-polymerization Technique, ”

at a Conference in West Berlin in October 1987,

organized by Internationale Arbeitsgemeinschaft

der Archiv, Bibliotheks-und Graphikrestauratoren.

Just when OTA was completing this report,

another U.S. firm from Linden, New Jersey announced a new process they had tested, ‘ ‘the Booksavers MGD process. It is a system based on existing industrial processes for mass sterilization of

medical products and food ingredients. Ammonia

gas, moisture, and ethylene oxide are introduced

into a vacuum chamber to react with paper components to form long-chain amines within the cellulose matrix of the book paper. According to the

developers, acids are permanently neutralized, the

amines provide an alkaline reserve and crosslinking between the reaction products strengthens the

paper.

Based on developer claims, the process would appear to have the potential to deacidify, strengthen,

and sterilize books with a gaseous process and overcome the safety issue for DEZ and the preelection

issue for the Wei T’o process. Tests performed by

the developer show increased fold endurance, uniformity of treatment based on pH measurements,

stability of pH change, and an alkaline reserve in

treated books ranging from 0.85 to 2.14 percent,

depending on the pH of the treated book. The developers have a facility that they claim can be modified to treat 20,000 books each day at a cost of $2

to $3 per book. They also claim that preelection

is not required and the books can be treated in

sealed cardboard cartons. 13 None of these claims

has been subjected to independent analyses and

OTA has not been able to evaluate these claims.

10For a more detai]~ description of this process see Otto Wachter,

“Techniques for Preserving Newsprint, ” in G,M. Cunha, Mass Deacidification for Libraries, Library Technology Reports, May-June

1987, pp. 445-458.

11 D, W,G. Clements, “Emerging Technologies—Paper Strengthening, ” Restaurator, vol. 8, 1987, pp. 124-128.

12 D.w. G. C]ements letter to Peter Johnson, July 31, 1987. The

cost estimate covers direct costs, overhead, and depreciation of capital.

1 Svladimir Zwass letter to Peter Johnson, Dec. 18, 1987.
9 8

ALKALINE PAPER PRODUCTION

One potential long-term solution to the problem

of acid deterioration of books is to print books on

acid-free, or alkaline, paper. 14 Alkaline paper has

a much longer life than acid paper. If all new books

were printed on alkaline paper, then it would not

be necessary to deacidify them. This section discusses the current status of alkaline paper production and the advantages and disadvantages associated with converting from acid paper production.

Status

Major differences between alkaline and acid paper include the type of sizing that is used to prevent ink from penetrating through it and the type

of filler used to make the paper smooth and opaque

and to improve printing properties. For alkaline

paper, two main types of synthetic sizing materials are used that are active on the alkaline side:

alkyl-ketene-dimer (AKD) and alkenyl succinic anhydride (ASA). Calcium carbonate is generally

used as the filler and alum is not required as a coreactant. These materials have become popular in

Western Europe and have a strong foothold in the

U.S. market. But, most paper in the United States

is made using rosin/alum sizing and kaolin clay

filler, which results in acidic paper.

Calcium carbonate has been used in printing and

writing paper production since the 1950s. It was

introduced not for its advantages to longevity, but

as a way of using byproducts from a pulping process. Calcium carbonate adds brightness and helps

promote good print quality through improved ink

receptivity. Calcium carbonate is a natural pH

buffer to acidic materials. Papers made with it have

an alkaline pH, i.e., above 7. Since calcium carbonate will decompose under traditional acidic

papermaking conditions, it must be employed in

an alkaline papermaking system.

I+ The Council on Library Resources Committee on Production

Guidelines in its 1982 report “Book Longevity” has recommended

that several categories of books be printed on acid-free paper. These

were primary printed sources, important works of fiction and nonfiction, collected editions, bibliographies, guides to collections, yearbooks,

gazetteers, scholarly periodicals and monographs, dictionaries, encyclopedias, and other reference books. Categories that need not be on

acid paper were also suggested to be textbooks, anthologies, vanity

publications, athletic and political hagiography, popularizations in all

fields, novelizations of films, formula novels, and most paperbacks.

There is general agreement that the market for

acid-free paper is growing, although it remains

small relative to total book paper production. Estimates published during the 1980s for the proportion of alkaline paper out of overall book paper

range from 1515 to 25 percent. 16 One source projected a 10-percent increase in the share of alkaline paper through the 1990s.17

According to the American Paper Institute, there

are no statistics breaking out the volume of alkaline paper produced, or the number of companies

producing it. About 30 companies make book publishing paper. Thirteen of these produce 20,000

tons/year or more, including three that produce

100,000 tons/year or more. Two out of the top three

companies have alkaline systems. There are about

200 corporations operating a total of about 1,000

pulp and paper mills in the United States today.

Therefore, the 30 companies making book paper

represent 15 percent of the total number of paper

companies.

Alkaline paper is more firmly established in

Western Europe (with the exception of Scandinavia) than in the United States. The percentage of

acid-free book paper production in Europe is probably about 50 to 65 percent of the total. Among

other reasons for the growth of alkaline paper making there, Europe has large easily mined chalk (calcium carbonate) deposits while clay is limited and

relatively expensive.

Advantages of Alkaline Paper

to Paper Manufacturers

Alkaline paper can provide several cost-saving

advantages to paper manufacturers for raw materials, pollution control, maintenance expenses, and

production volume. However, these advantages are

highly specific to individual plants. Other advantages relate to paper quality and longevity. While

IJChmdm J. Shdmi and W.K. Wilson, ‘‘Preservation of Libraries

and Archives, American Scientist, VO1.75, May-June 1987, pp.

240-251.

IGLibraV of Congress, “Paper Durability for Book Longevity, ”

Technical Note 116, Herald of Library Science, vol. 22, July-October

1983; and Committee on Production Guidelines for Book Longevity,

Council on Library Resources, Inc., “Book Longevity, ” 1982.

ITConversation with Tom Lord, James River COT., JUIY 31, 1987.
9 9

most manufacturing costs (e. g., labor) are comparable for acid and alkaline paper of similar quality,

some manufacturers find cost advantages in switching to alkaline processes.

Cellulose fiber is the most important raw material in paper. For mills that have to buy fiber on

the open market in particular, the price of fiber is

an important cost in paper manufacturing. Because

of the chemically reactive synthetic sizing, alkaline

paper is stronger than acid paper. Thus, manufacturers can lower the fiber content of paper while

increasing filler and ash content, and get equivalent strength for less cost.19 Estimates of savings

range from $25 to $45 per ton for some grades.

While not all types of paper can use increased

amounts of filler, more than half the market could

benefit. The incentive to lower fiber content is increasing, as the price of fiber is rising.20

This potential cost advantage of the alkaline process is probably the most important factor in increasing the market share of alkaline paper. However,

its impact may be limited. Large paper manufacturers usually own their own pulp mills, often located close to the paper mill. The cost of fiber for

these manufacturers is low. Therefore, the economic advantage for conversion would be less than

for many smaller firms. In some cases reduced fiber content may be a disadvantage to manufacturers, as discussed later.

Another cost savings for raw materials applies

to some specialty papers. Calcium carbonate can

substitute for titanium dioxide, which is more expensive and more difficult to obtain.

Pollution control costs may be lower for alkaline

production. Effluent from acid paper making has

to be adjusted by adding alkaline materials. No adjustment is needed for effluent from alkaline processes, which comes out with pH near neutral. Also,

alkaline effluent has less biochemical oxygen demand (BOD), reducing the BOD load at waste

treatment plants.21 Another environmental advantage for alkaline paper making is the reduction of

‘8JaY ~ B’own ‘ ‘The Once and Future Book: The Preservation

Crisis, Wilson Library Bulletin, May 1985, pp. 591-596.

IgConversation with Terry Norris, July 7, 1987, Jan. 11, 1988.

ZoConversation with Robert Olsen, P, H. Glatfelter, July 9, 1987.

ZIConversation with Robert Olsen, P. H. Glatfeher, July 9, 1987.

specific pollutants of concern generated in acid paper making, such as aluminum .22

The importance of these benefits varies. Pollution abatement advantages are usually substantial

for the large plants that produce the bulk of U.S.

paper. Most large U.S. paper plants have pulp mills

and wastewater treatment facilities co-located onsite. Pulp mills produce far more effluent than paper manufacture, and if a company can treat pulp

mill effluent, it has little problem treating paper

plant effluent.

Some maintenance costs may be lower for alkaline production. To reduce water consumption,

most paper making companies recycle the water

used in manufacturing. When water from acid

processes is recycled, alum buildup is experienced,

and the system needs to be purged periodically.

Compared with the alum/rosin process, less alkaline filler is lost during paper making.

Whether switching to alkaline processes brings

cost advantages depends on the specific circumstances of the manufacturer. One manufacturer reported that while the problems encountered are

different, there were no major advantages to alkaline in terms of their cleaning needs. Some firms

would need to modify their bacteriological control

systems if they were to convert to alkaline paper

production.

Decreased water consumption is another possible benefit, to the extent that alkaline processes enable increased recycling.

Alkaline paper processes are less corrosive than

acid processes to paper-making machinery. For

some manufacturers the advantages of this apply

mainly to older non-stainless steel equipment. However, the corrosion advantages of alkaline processes

are tangible even for stainless steel.

Some mills can produce greater volumes of alkaline paper than acid paper per unit of time because

of differences in water retention. For example, if

a mill is drier limited, it can make it go faster and

boost production.

Other potential advantages of alkaline production relate to paper quality and longevity. Alkaline

Zzconvemation with Tom Commeau, Champion International, JUIY

15, 1987.
100

paper has greater strength than acid paper. The

alkaline process also produces advantages in other

areas of quality: alkaline paper is brighter, more

opaque, and smoother, which improves print quality and color reproduction. It also reduces mottling.

These potential benefits depend on paper grade,

the quantity of filler used, the specific type and quality of the calcium carbonate pigment used, and

other material and equipment changes.

Although the market for alkaline paper is not particularly strong at present, some in the paper industry believe the advantages of alkaline paper in

longevity will become increasingly important to

publishers and their clients.

Disadvantages of Alkaline Paper

to Paper Manufacturers

Despite the advantages listed above, there are

important obstacles to increasing the role of alkaline paper in paper manufacturing including low

demand and the costs of conversion. Growth in the

share of alkaline production will be slow until these

obstacles are lessened.

The market for alkaline paper, while growing,

is not strong enough to motivate major increases

in production by paper manufacturers. In general,

most U.S. publishers and their customers do not

see sufficient advantages to alkaline paper to cause

them to select it over comparably priced acid paper.

Publishers are constrained by lack of demand

from commercial booksellers. Whether or not a

book is printed on alkaline paper is not an important consideration for most buyers at the retail

level .23 The main demand for acid-free books comes

from libraries, which account for about 10 to 15

percent of total publishers’ sales.24

The effects of low levels of demand are compounded by the size of the book paper market. Book

paper is a small part of total writing/printing paper production, and an even smaller part of total

paper production. In 1986, about 78 million tons

of paper and paperboard were produced, out of

which 20.5 million tons were printing/writing paper. Book paper accounted for 950,000 tons, less

than 5 percent of printing/writing paper and less

than 2 percent of total paper production.25

Most of the paper used in U.S. books comes from

companies whose main products are not book paper. Perhaps one-quarter of book paper comes from

companies whose main product is such paper, and

who might be expected to be more sensitive to whatever demand exists for paper longevity. The remainder is manufactured by companies with diversified product lines. In many cases, book paper

accounts for only a small fraction of the total sales

of paper makers. It appears that there is little incentive on the production side to change manufacturing processes at this time.

Switching to alkaline production can be costly

for manufacturers, and switching to alkaline paper brings costs to users. Many producers and customers do not want to take the time and effort to

adapt their processes to something new. Since a top

management commitment to invest in the ‘‘learning curve’ of a new process would be needed, paper manufacturers would require a similar commitment from their customers.

For manufacturers, switching to alkaline paper

may involve substantial retrofitting costs. Depending on the mill, new chemical preparation systems

will be required, incorporating different internal

sizing, mixing, and storage equipment. The cost

may be over $1 million for even a medium tonnage

paper mill.26

Another factor affecting cost is how calcium carbonate is obtained. Some manufacturers have chosen to build a plant onsite to make calcium carbonate precipitate, thereby gaining good quality

control—important in assuring that calcium carbonate particles will be uniform in size. However,

such plants are expensive, about $10 million. The

other route is to buy fine ground calcium carbonate

direct from quarries, with some sacrifice in quality. Depending on transportation costs, buying

from quarries can be cheaper than building a plant.

‘3JaY w. B’OWII> “The Once and Future Book: The Preservation

Crisis, ” Wilson Library Bulletin, May 1985, pp. 591-596.

Z4Lauren Jackson-Beck, “The Problems of Preservation: Can

Librarians and Publishers Solve Them?” Collection Budding, summer 1985, pp. 21-25.

ZsConversation with James HutchiSon, American paper Institute,

July 14 and 23, 1987.

2

’Conversation with Tom Commeau, Champion International, July

15, 1987.
101

Alkaline sizing materials are also $1.00 to $1.50

per dry pound more expensive than acid sizing and

it is therefore slightly more expensive ($0.50 to

$1/ton) to make alkaline paper water resistant.27

Although to some the increased expense of water

resistance could be an important impediment, for

most these costs are not significant obstacles to the

spread of alkaline paper-making.

Probably the most important disincentives to the

spread of alkaline paper-making are the general

problems of changing over to a new system. Mills

operate on modest margins and high production

rates, and taking the time to learn new methods

is costly. Similarly, customers used to acid paper

may have to make adjustments in dealing with a

new product. For example, some dyes that work

with acid paper do not work well with alkaline paper. Also, alkaline paper has different ‘‘rUnnability" characteristics than acid paper-that is, it feeds

through machinery differently. Industries making

envelopes, tablets, etc. have had to change some

of their manufacturing procedures .28 In particular,

operators have had to slow down the machinery that

converts paper from rolls to single sheets and other

products. It is likely that this problem will be resolved within a few years, this has affected the

qTConver~ation with Jay Vreeland, S.D. Warren, JUIY 9, 1987.

28R .G. Johnson, “U.S. Alkaline Fine Papermaking To Experience

Slow But Steady Growth, ” Pulp and Paper, December 1986, pp.

66-67.

acceptability of alkaline paper to some important

categories of users.

Adjustments in processes (e. g., in altering dyes)

are relatively easy. With adjustments, alkaline paper is equal to or better than acid paper for most

uses. Still, without a cost differential in favor of

alkaline paper, there is little incentive for end users

to take the effort and cost of dealing with conversion problems—and little incentive for paper manufacturers to risk sales by introducing alkaline in

place of acid paper.

As mentioned above, one of the main selling

points of the alkaline process is its potential for saving costs through fiber reduction. This also has a

down side. Many customers of paper manufacturers (e. g., makers of envelopes) sell large quantities

of waste paper to recyclers, often deriving substantial revenue. Rising pulp prices have made waste

paper more attractive as a raw material.29 There

is concern by these customers that decreasing the

fiber content of the paper they use will make the

waste paper less attractive to recyclers. In turn, paper manufacturers considering alkaline processes

are concerned that their clients might prefer acid

paper for this reason.

ZgpaperChemjcds &larkets in Europe (New York, NY: Frost &

Sullivan, Inc., 1982), p. 32.

DISCUSSION

No mass deacidification systems are operating

or are being built, designed, or planned on the scale

envisioned for the Library’s DEZ full-scale facility (over 1 million books per year).

One mass deacidification pilot plant using a Wei

T’o system is in operation at the National Archives

of Canada. This plant has been in operation for

7 years and treats about 40,000 books per year—

roughly the capacity of the Library’s DEZ pilot

plant built for engineering testing in Texas. The

“Bookkeeper” process has also been developed and

a pilot plant system has been designed, The system has yet to be built but it would have a capacity on the order of the DEZ and Wei T’o pilot

in operation (a Wei T’o spraying system at Princeton and an aqueous deacidification and strengthening system in Austria), the French are testing a

small pilot plant based on the Canadian design, and

the English have just begun to design a small-scale

system that would both strengthen and deacidify

books, but this is still at a very early stage of development.

Only two processes, Wei T’o and the Bookkeeper

have had sufficient development at the scale required by the Library to merit consideration as options to the DEZ process at this time.

There have been no independent tests or evaluplants. Other systems of a much smaller scale are ations of the cost and effectiveness of these proc-
102

esses. All data and estimates have been developed

by the firm or organization that is promoting the

process (including the Library). Without some independent analyses with standard test materials and

procedures, a definitive comparison of the processes

cannot be made.

In general, all of the processes neutralize the acids

present in the paper. Each of the developers present

data that indicate their process can extend the life

of a book by roughly the same amount (two to five

times), based on fold endurance after accelerated

aging. Other supporting analyses are limited mainly

to pH measurements and alkaline buffer contents,

resulting in a limited amount of information on

which to assess the processes.

With this in mind, a qualitative evaluation of the

advantages and disadvantages of the three principle mass deacidification processes follows.

The DEZ system is capable of treating books with

a high degree of uniformity. The zinc oxide buffer

can be controlled and leaves the paper relatively

neutral regardless of the paper’s initial acid content. It is compatible with most other book materials, especially inks and pigments, and requires little or no preelection. It is also capable of treating

other formats. Health and environmental impacts

of the system are considered to be minimal, but are

currently or will soon be investigated in greater

detail.

The key technical disadvantage of the DEZ system is that safety is a critical issue in the operation

of the plant and requires added costs to manage.

There are small but serious risks to plant workers

and equipment and to a limited extent, the public

(i.e., during the transportation of DEZ to the plant).

It is also capital intensive and requires a relatively

large initial investment.

The Wei T’o system is based on a chemistry that

is accepted in the preservation community. The pilot plant in Canada has been in operation for 7

years. Unfortunately, development of the system

has not progressed much during that time, although

the operation of the plant is routine. The Wei T’o

system is currently moderate in cost and investment. It is relatively safe compared to the DEZ

plant. Although the health impacts of the process

are not considered to be problem, they have not

been formally assessed.

The principal disadvantage of the Wei T’o process is that its solvents are not compatible with a

number of common book materials and artifacts

(i.e. stamp inks, label adhesives, certain pigments,

and certain plastic laminated book covers). The

Canadian operation rejects 20 to 25 percent of the

books sent for treatment. The amount of alkaline

buffer appears to be less than that deposited by the

DEZ process and varies with the concentration of

the solution and the initial acid content of the

papers. There are no data describing the uniformity of the treatment. One book picked at random

during an OTA visit showed non-uniform treatment of the pages. The amount of fluorocarbons

released during the total process is below current

regulations. However, the uncertainty about future

regulations makes investment and operating costs

more uncertain.

The Bookkeeper process is the simplest of the

three. It has the shortest cycle times, requiring no

drying as do the other two processes, and capital

investment would probably be low. Because of the

chemicals it uses, compatibility with inks, colors,

etc. is not expected to be much of a problem, although not enough tests have been conducted to

determine what, if any, preelection is necessary

(e.g., plastic Covers may be a problem as with the

Wei T’o process). Tests by the developer have

shown that treatment can be uniform throughout

the book and page. The alkaline buffer does not

depend on the moisture or initial acid content of

the paper. Health impacts are not considered a

problem, although no formal assessment has been

made.

The primary disadvantage of the Bookkeeper

process is that it relies on its alkaline reserve to neutralize the paper over time. Although fold endurance tests after aging show results similar to those

of the DEZ process, the depletion of the alkaline

reserve would be expected to be faster. Uncertainty

about future regulation of fluorocarbons makes capital and operating costs uncertain. Also, the level

of development of the total system is behind that

of the DEZ and the Wei T’o systems.

The use of alkaline paper in books is not expected

to grow significantly in the near future. The advantages and disadvantages of switching to alkaline paper varies from producer to producer and

publisher to publisher. The major factor inhibit-
103

ing a wider conversion is that book paper makes

up a small percentage of the paper market, and the

library community and those interested in preservation make up an even smaller percentage.

Since there are no reliable data to estimate the

trends in the use of alkaline paper, OTA cannot

make a quantitative estimate of costs to switch to

alkaline paper. It would be desirable, however, to

compare alkaline paper production costs to future

deacidification costs for some category of books or

materials that end up being valuable in library collections. Prior to making such estimates, however,

the library community would need to select and

agree on those categories. While such an approach

would not have any effect on the brittle book problem of today, or even a few years from now, it might

result in substantial savings in the long run.
Appendixes
Appendix A

Definition of Terms

Accelerated Aging: exposing paper to high temperatures and varying humidity to simulate natural aging.

Acid Books: books whose pages have a pH of less than

7. The pages are not yet brittle, but because of their

acidity they will become brittle in time.

Acid-Free: paper or books made with paper produced

by alkaline manufacturing processes. Although the

paper may not be totally free of acid, its pH is nearly

neutral.

Aqueous Solvent: water or watery substance used to

dissolve chemicals.

Autocatalytic: a self-sustaining decomposition of a

chemical compound, often accompanied by a very

rapid release of energy.

Brine Seal Tanks: seal pots that use brine to neutralize

DEZ.

Brittle Books: books whose pages have become so fragile that they cannot be circulated.

Cellulose: primary plant fiber used to make paper.

Compatible: indicates that a chemical or process has

no adverse reaction with the various materials or

chemicals found in books (e. g., the paper’s cellulose,

sizing, fillers, pigments, inks, glues, labels, covers,

etc.).

Dew Point: temperature at which vapor condenses into

liquid.

Distributive Control System (DCS): a computer system that monitors and helps to operate chemical

processes.

Fold Endurance: the number of folds a piece of paper

(under tension) can withstand before it breaks (see

TAPPI standard - T511.50-69).

Hemicellulose: a substance like cellulose, but less

complex.

Inert Gas: gas such as nitrogen, having few or no active properties.

kPa: kilopascal, a unit of pressure roughly equal to 1/100

of atmospheric pressure.

Lignin: unstable constituent of wood pulp that leads

to rapid deterioration of paper.

Load Cells: devices used to measure weight.

Loss Time Accidents: industrial mishaps that result in

worker(s) not being able to return immediately to

work.

Mass Deacidification Process: chemical treatment to

neutralize acids in paper and provide an alkaline

buffer that can handle several closed books at one

time.

Metal Alkyls: a chemical compound linking a metal

atom or atoms with a hydrocarbon radical of the form

CuH2n+ 1; very reactive.

Nonaqueous Solvent: chemicals (other than water) used

to dissolve other chemicals. Nonaqueous solvents used

in deacidification techniques include methanol.

Paper Brightness: ability of a paper to reflect light.

Paper Durability: relates to the physical and mechanical properties of paper

and its ability to resist wear and tear.

Permanent Paper: paper that is usually acid-free and

is made to resist the effects of aging to a greater degree than ordinary paper.

TAPPI Standards:

Type I - Maximum Permanence

pH = 7.5 -9.5 + 2 percent MgCO3 or CaC O3

Type II - High Permanence

pH = 6.5 -8.5

Type III - Medium Permanence

pH greater than 5.5

Paper Permanence: ability of paper to maintain any

or all of its properties over time.

Permissive: a specified set of process parameters (including interlocks) that must be met before starting

the next process step.

pH: a measure of acidity (or alkalinity). On a log-scale

from O to 14, a pH of 7 is neutral. A pH less than

7 indicates the presence of acids, a pH greater than

7 indicates the presence of alkaline materials.

Plant Commissioning: starting up and checking out,

both individually and as a system, the various pieces

of equipment to be used in a processing plant.

Polymerization: the process of joining two or more like

molecules into a more complex molecule whose molecular weight is a multiple of the original and whose physical properties are different.

Preelection: screening to determine which books can

be safely treated.

PSIG: pounds per square inch gauge; pressure measured relative to atmospheric pressure which equals

14.7 pounds per square inch.

Pyrophoric: chemical that spontaneously ignites when

exposed to air.

Safety Interlocks: a specified set of positions for various pieces of equipment (e. g., on/off or open/closed)

that must be met before another operation can occur.

Seal Pot: tank containing agents that can neutralize

DEZ; used to remove DEZ vapors from effluent

vapors before releasing them to the atmosphere.

Sizing Agent: material added to paper during manufacture to reduce penetration of liquids and prevent

inks from blotting.

Specific Heat: the heat required to raise the tempera107
108

ture of one gram of a substance one degree Centigrade.

Strengthening techniques: methods for restoring brittle papers so that they can be handled.

Surfactant: a chemical used in a liquid dispersion to

keep other particles equally dispersed within the

liquid.

TAPPI: Technical Association of the Pulp and Paper

Industry.

Thermochemical Properties: characteristics dealing

with the interrelation of heat with chemical reaction

or physical change of state.

Thermodynamic Properties: characteristics dealing

with mechanical action or heat.

Threshold Limit Value (TLV): a maximum level of

exposure set by the American Conference of Governmental Industrial Hygienists (ACGIH) for various industrial substances.

Titration: chemistry method for determining the

strength or concentration of a solution,

Torr: a unit of pressure equal to 1/760 of atmospheric

pressure.
Appendix B

Library of Congress’

Operating Cost Estimates for

Full-Scale Mass Deacidification Facility

November 1987

This appendix contains the estimates of operating costs

for a full-scale mass deacidification facility prepared by

the Library of Congress and submitted to OTA as of

November 1987. All estimates are preliminary and subject to refinement based on results of tests at the Texas

Alkyls pilot plant. The appendix consists of three parts:

1.

2.

3.

The basis for costs describing assumptions used to

develop operating cost estimates.

Cost tables and discussion showing operating cost

estimates at different production rates in terms of

total treatment costs, per-book costs, and detailed

costs for a facility treating 1 million books per year.

These detailed costs are further explained in a series of notes.

Standard operating costs that are not applicable

to the proposed facility.

Basis for Costs

Preliminary annual operating costs for the Ft. Detrick

Book Deacidification Facility are based on two to four

T/V Chambers operating on a 72-hour treatment cycle

or less for 24 hours per day, 7 days per week, and 350

days per year.

A checklist to aid in determining the Annual Operating Costs was prepared by modifying a similar table in

Perry’s Chemical Engineers’ Handbook (Perry, Chilton, Kirkpatrick, 4th ed., McGraw-Hill, 1963). This

checklist was prepared in two parts: Part 2 - table B-1

includes all those items assumed applicable to a

government-owned installation at Ft. Detrick, and Part

3 lists those items not applicable.

Part 2- tables B-2 and B-3 show for the Ft. Detrick

Facility a summary of the annual operation costs in dollars per year and in dollars per book, respectively, for

four annual production rates.

The cost of book handling at the Library and book

transportation to and from the plant are not included

as part of plant operating costs because these tasks would

have to take place independent of the process used. Previous estimates placed this figure at approximately $0.70

per book.

Contractor supervision and operation of facility is

assumed.

Operating data, soon to be obtained from the Texas

Alkyls Small Scale Test Deacidification Facility in Deer

Park, Texas, will be used to refine the cycle times and

the number and the capacity of T/V Chambers. With

these data and from the design of the Ft. Detrick Facility the costs estimated in table B-1 will be updated.

Cost Tables and Discussion

Table B-2 shows the major annual operating costs for

four production rates.

Table B-3 converts the dollar costs in table B-2 to dollars per book treated.

Table B-1 is for an annual capacity of 1 million books,

and shows a breakdown of costs for each group of costs

shown in table B-3.

Items Not Applicable to

Ft. Detrick Facility

1. Plant Costs

the

● Company contribution of profit sharing or thrift

plan

2. Plant Overhead

● Purchasing

• Personnel and industrial relations

● Automotive and rail switching

● Plant hospital and dispensary

● Cafeteria and club rooms

● Taxes on properties and operating licenses

● Insurance - property

● Depreciation

3. Distribution Costs

●

●

●

●

●

●

Containers and packages

Freight

Operation of terminals and warehouses

Wages and salaries plus fringe benefits

Operating materials and utilities

Rental or depreciation

109
110

Table B-l.—Breakdown of Annual Operating Costs at 1 Million Books per Year

Product

Producer

Location

Byproducts

Process

Operation

Annual capacity

Fixed investment

Stream days

Cost Component

Deacidified Books

Contractor to the Library of Congress

Ft. Detrick, MD

Ethane and water extracted from books

Under vacuum: books dehydrated,

diethylzinc reacted with remaining

water and acid and dehydrated

Batch cycles

500,000 to 2,000,000 books per year

See Appendix C: Capital Cost Estimate

350 24-hour days

Dollar cost

per year

1. Plant Costs

1.1 Raw Materials

—Standard Test Books . . . . . . . . . . . . . . .

1.2 Processing Chemicals

Diethylzinc . . . . . . . . . . . . . . . . . . . . . . . . . .

—Treated Water . . . . . . . . . . . . . . . . . . . . .

—Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . .

1.3 Operating Supplies

—Dowtherm J . . . . . . . . . . . . . . . . . . . . . . .

—Lubricating oil . . . . . . . . . . . . . . . . . . . . .

—Kerosene . . . . . . . . . . . . . . . . . . . . . . . . .

—Refrigerant . . . . . . . . . . . . . . . . . . . . . . . .

—Supplies/Sundries . . . . . . . . . . . . . . . . . .

1.4 Utilities

—Electricity . . . . . . . . . . . . . . . . . . . . . . . . .

—Cooling Water . . . . . . . . . . . . . . . . . . . . .

—Instrument Air . . . . . . . . . . . . . . . . . . . . .

—Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.5 Maintenance Materials* . . . . . . . . . . . . . . .

Subtotal: Plant Costs . . . . . . . . . . . . . . .

● Replacement parts, repair of equipment, etc.

2. Operating Labor

2.1 Plant manager . . . . . . . . . . . . . . . . . . . . . . .

$ 13,000

800,000

3,000

30,000

500

2,000

500

1,000

3,000

70,000

10,000

1,000

3,000

60,000

$997,000

$65,000

2.2 Operation engineer. . . . . . . . . . . . . . . . . . . 45,000

2.3 Chemical/computer technician . . . . . . . . . 40,000

2.4 Eight operations/technicians/book

handlers @ $32,000 . . . . . . . . . . . . . . . . . . . 256,000

2.5 Day shift maintenance person . . . . . . . . . 35,000

2.6 Outside maintenance support on

demand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20,000

2.7 Total direct labor. . . . . . . . . . . . . . . . . . . . . $461,000

2.8 Payroll burden (fringe benefits) for

Federal OASI, Workman’s Compensation

Insurance, contributions to pension, life

insurance, thrift plan, vacations,

holidays, sick leave, overtime premium . 152,000

Subtotal: Operating Labor . . . . . . . . .

3. Plant Overhead

3.1 Administration (by plant manager) . . . .

3.2 Indirect labor

—Laboratory technician. . . . . . . . . . . . .

—Secretary/receptionist . . . . . . . . . . . .

—Technical service & engineering . . .

—Shops and repair facilities . . . . . . . .

—Shipping and receiving department .

—Payroll burden of 3.2 Indirect Labor

3.3 Inspection, safety and fire protection .

3.4 Accounting, clerical and stenographic

3.5 Communications: telephone, mail,

teletype, modem . . . . . . . . . . . . . . . . . . .

3.6 Plant custodial . . . . . . . . . . . . . . . . . . . .

3.7 Plant protection. . . . . . . . . . . . . . . . . . . .

3.8 Waste disposal . . . . . . . . . . . . . . . . . . . .

3.9 Insurance, third party liability. . . . . . . .

Subtotal: Plant Overhead. . . . . . . . . .

4. Administrative Expense

. . $613,00 0

. . see 2.1

. . $28,00 0

. . 22,000

. . Note 14

. . Note 15

. . Note 16

. . 17,000

. . Note 17

. . Note 18

. . 3,000

. . 10,000

. . Note 17

. . 10,000

. . 20,000

. . $110,000

Contractor’s fee taken as 15 percent of

2.0 Operating Labor subtotal, $613,000,

pIus $67,000 of 3,2 Indirect Labor . . . . . . $102,000

Total Annual Operating Cost for 1

Million BPY at Ft. Detrick ... ... ... . .$1,822,000

1. 1.1 Raw Materials - The books to be treated are not considered a cost item but Standard Books for quality Control are.

2. 1.2 Processing Chemicals: DEZ usage, the major chemical cost, is baaed on an average 1 1/2 percent DEZ being laid down in an average 1.66 pound book which is

equivalent to 72 cents per book for $17.00 per pound DEZ. Until better operating data is obtained 8 cents was added for small losses and wastage, e.g., equipment

and line cleaning, to develop the 60 cents.

3. Other Chemlcals: How much 1.2 Nitrogen (considered a processing chemical for purging, particularly, the T/V Chambers) to be used, is now a guess taken as 250

tons $120/ton @ $30,000.

4. 1.3 Operating Supplies: Dowtherm J, used as the heat transfer oil, may be needed for periodic replacement. The replacement cost is estimated at about $500 per

year. Lubricating oil for the pumps will probably require changes costing an estimated $2,000 per year. Kerosene, the sealant for the two Seal Pots, and for clean

out of equipment Is a minor cost. Supplies/sundries: other lubricating oils, greases, about $3,000 per year for refrigerant, chemicals for the laboratory and gasket

replacement, all usually a minor cost item, will be better known toward the beginning of spring 1966.

5. 1.4 Utilities: The amount of electricity, the major utility cost Item for power, lighting, refrigeration and air conditioning, will be batter known in the spring of 1966

after a few small scale tests and the redesign of the Ft. Detrick deacidification facility. It is estimated now as l,400,000 kWh @ 5 cents/kWh - $70,000. Cooling

water, instrument air, and steam (for heating comfort) are minor utility cost items,

6. 1.5 Maintenance Materials - Taken as a percentage of the chemical processing part of the Ft. Detrick Facility.

7.2. Operating Labor - There will be better data from the Small Scale Plant Operations but the labor for Ft. Detrick remains a good but tight estimate until Ft. Detrick

is in operation. There will be more clarification for job assignment and responsibilities details. It is assumed that one of the two shift operators will assist in DEZ

cart movement and assist in the Quality Assurance Laboratory.

8.2.1. A Plant Manager or similarly titled parson la needed to be in charge and to interface with Ft. Detrick and Library management. The same person, after the start-up

period, should have ample time to manage other operating sites. Thus, a smaller cost than the $65,000 salary plus benefits could be required.

9.2.4. Eight oparational technicians/book handlers are determined as two people per shift for 168 hours par week @ 40 hours per person -8.4 people. Assume some

of the eight will work overtime to cover for 0.4 person, sick leave, vacation, holidays, jury duty, military service, etc. The two operators per shift was chosen baaed

on the emphasis on safety even though there may not be sufficient activities to occupy two people after start-up and the plant is run routinely.

10. All book movements at the facility are planned to be done by the operators.

11.2.5. Direct Maintenance Labor - These costs will be batter defined after the redesign of the Ft. Detrick facility and the operation of the pilot plant.

12.2.8. Payroll Burden on ail Labor Charges - this major cost item, lumped as one percentage of labor for all benefits as defined in Reference.

13. 3.1 Administration - This is assumed under 2.1 Plant Manager.

14. Technical service and engineering will be by contractor and covered under administrative expense.

15. Shops and repair facilities are included under maintenance labor.

16. Shipping end receiving department to be handled by shift operators.

17. inspection, safety end fire protection and plant protection provided by Ft. Detrick.

18.3.4. Accounting provided by contractor and secretary/receptionist does clerical and stenographic.

19.3.8. Waste Disposal of 10,000 gallons at $1.00/gallon -$10,000.

20.4. Administrative Expanse: Contact was made with contracting companies in a somewhat similar position to establish the rate of 15 percent and its basis. Also

sea Notes 14 and 15 preceding.
111

4. Marketing Costs ●

5. Administrative Costs ●

●

●

●

●

●

●

General account, clerical auditing ●

Central engineering and technical ●

Legal and patent ●

Within and outside the facility ●

Payment and collection of royalties ●

Contributions and dues to associations

Financial

Debt management

Maintenance of working capital

Credit functions

Communications and traffic management

Central purchasing activities

Taxes

Table B.2.—Annual Operation Costs in Dollars per Year

Capacity in millions of books per year (dollars per year)

Cost components 0.5 1 1.5 2

Plant costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... ... ... $ 551,000 $ 997,000 $1,450,000 $1,897,000

Operating labor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611,000 611,000 611,000 611,000

Plant overhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110,000 110,OOO 110,000 110,000

Administrative expense. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102,000 102,OOO 102,000 102,000

Total unit treatment cost at Ft. Detrick . . . . . . . . . . . . . . . . . . . . .. .$1,374,000 $1,822,000 $2,273,000 $2,720,000

Table B-3.—Annual Operation Costs in Dollars per Book

Capacity in millions of books per year (dollars per book)

Cost components 0.5 1 1.5 2

Plant costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....1.10 1.00 0.96 0.95

Operating labor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .1.22 0.61 0.41 0.31

Plant overhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....0.22 0.11 0.07 0.05

Administrative expense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....0.20 0.10 0.07 0.05

Total unit treatment cost at Ft. Detrick . . . . . . . . . . . . . . . . .....2.74 1.82 1.51 1.36
Appendix C

Library of Congress’ Capital Cost Estimates

for Full-Scale Mass Deacidification Facility

November 1987

This appendix includes the estimates of capital costs

for a full scale mass deacidification facility prepared by

the Library of Congress and its contractors in November 1987. This facility would be composed of two structures, a warehouse support building and a chemical

treatment building. The appendix consists of four parts:

1.

2.

3.

4.

The cover memorandum provides some of the major assumptions used to come up with the

estimates.

Table C-1 lists the construction costs for the chemical treatment facility.

Table C-2 lists the space requirements for the

different components of the warehouse support facility and the estimate of costs to construct such

space.

Table C-3 lists the changes in equipment that will

probably be required to scale-up the Texas Alkyls

pilot plant into a full-scale facility that can treat

1 million books per year.

Table C-1.—Capital Cost Estimate for a

One. Million. Book-per-Year

Deacidification Chemical Process Facility

Item Cost estimate

Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 40,000

Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40,000

Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 875,000

Spare Parts (Inventory). . . . . . . . . . . ., . . . . . . 50,000

Pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250,000

Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275,000

Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450,000

Building (Shell) . . . . . . . . . . . . . . . . . . . . . . . . . a

Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50,000

Coatings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20,000

Fire Protection ., . . . . . . . . . . . . . . . . . . . . . . . 50,000

Field Indirects . . . . . . . . . . . . . . . . . . . . . . . . . . 300,000

Engineering and Home Office . . . . . . . . . . . . 190,000

Fee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200,000

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $2,750,000

~lncluded in total space and capital estimate for warehouselprocessing facilitY.

Table C-2.—Capital Cost Estimates for a Deacidification

Plant Office/Warehouse Support Facility

Square feet

1.0

1.1

1,2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

Administration

Vestibule .

Reception and Waiting ~ ~

Plant Manage r

Operations Engineer ~ ~ ., .,

Chemical/Computer Technicia n

Office. ., ... ~ ~

Offic e

copy .,

Storaa e

1.10 Toilet; (2 @ 80 SF )

1.11 Janitor Close t

1.12 First Aid ., ~ ~ ~ ~

1.13 Lunch Room .

1.14 Conference Room w/Scree n

2.0

2.1

2.2

2.3

2.4

2,5

2.6

2.7

2.8

3.0

3.1

3.2

3.3

3.4

4,0

4.1

4.2

4.3

4.4

5.0

5.1

5.2

Subtota l

Warehouse/Processing

Pallet Storag e

Chemical Process Area.

Quality Assurance Laboratory ~

Maintenance ... ., ., . . .,

Men’s and Women’s Lockers

Loading/Unloading .,

Spare Parts Storag e

Service Oock

Subtotal .,

Building Support

Mechanical Room

Electrical Room ., ~ ~ ~ ~ ~

Telephone Equipment Roo m

Building Maintenance Room.

Subtota l

Support Building Area :

Support Building Gross :

Support Building and Chemical

Process Totals (square feet): . ,

Gross SF Cost/SF

Building Cost Estimate

75

190

120

100

100

100

100

80

80

160

35

165

250

300

1,855

8,000

8,000

750

1,100

400

1,050

1,000

300

20,600

1,500

1,000

120

120

2,740

8,178

2,818

30,996

Amount

Administratio n 2,504 $72.00 $ 180,288

Warehouse/Processing ~ 22,660 1,246,300

Building Support 3,014 55.00 165,770

Building Walls ~ ~ ~ 3,818 55.00 209,990

Total Building Cost. 31,996 $1,802,348

Project Cost Estimate

Building Cost $1,802,348

Site Work ~ ~ ~ ~ ~ ~ ~ ~ ~ 328,000

Total Project Cost (w/o Process Equipment) ., ,$2,130,348

112
113

TO:

FROM :

SUBJECT:

Mr. Peter Johnson

Office of Technology Assessment

Peter G. Sparks

Director, Mass Deacidification Program

LIBRARY OF CONGRESS

DATE: November 23, 1987

Capital Cost Estimates for Main Deacidification Facility

As requested the Library has taken steps to come up with capital cost

estimates for the Ft. Detrick facility. These costs were based on our current

thinking that the facility would consist of two separate structures--a support

facility and a chemical treatment facility . It is unclear at the moment ho w

these structures would be connected but we see this as a minor cost. W e

worked with the architect that had previously been for the project Shertz,

Franklin, Crawford and Shaffner in Roanoke, Virginia and with S&B Engineering

in Houston, Texas to get estimates. Both estimates were done in consultation

with our engineer who reviewed the chemical plant costs in detail.

The estimates for the warehouse support facility are fairly selfexplanatory showing the various functions that will be in the building with

gross square footage allocated to each and the construction cost estimate at

the end. These data are shown in table C-2.

The estimates for the chemical treatment plant are based on a

hypothetical chamber size and configuration since there is no firm design in

place for this part of the facility. The chemical part of the facility and

the control room flow from the design of the pilot facility. The chemical

facility estimates are based on a number of assumptions which are listed

below:

1.

2.

3.

4.

5.

6.

7.

The four chamber design has been chosen to stay within the

capacity of commercially available vacuum pumps.

The unit can be installed in a building approximately 100 feet by

80 feet.

Utilities such as electricity, instrument air, fire water, and

potable water are available at battery limits.

No site development work is included.

No emergency power generator is provided.

Estimate is based on Houston area open shop labor rates.

No contingency is added to the estimate.

An analysis of the large scale facility requirements and equipment

changes are shown in table C-3. Construction cost estimates for a one millio n

book per year treatment facility are given in table C-1.

Attachments
114

Table C-3.–Equipment Changes for Scale-UP

Pilot unit 1 mm book/year

1. Design items as designed facility

No. of Chambers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

No. Carts in Chamber

(27" WX48"H X41- L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Average No. of Books per Cart . . . . . . . . . . . . . . . . . . . . . . . .

No. Books/Chamber—Maximum . . . . . . . . . . . . . . . . . . . . . . .

Design Cycle Length’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cycles/Year/Chamber. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chamber, Hrs. in Operation . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hrs. Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overall Service Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Per Chamber per Cycle, Ibs.

DEZ Consumed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C2H6 Released.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Annual Rates, Ibs/yr.

DEZ Consumed.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C2H6 Released.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chamber, Diameter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DEZ Circulation Rate, Ibs/hr. . . . . . . . . . . . . . . . . . . . . . . . . . .

N2DD Circulation Rate, lbs/hr. . . . . . . . . . . . . . . . . . . . . . . . . .

‘Does not Include time to load or unload chamber.

1 4

5

224

1,120

36

223

8,028

732

91.6

—

360

30.5

—

—

—

72.52

35.52

23.31

11.35

64,687

31,505

6’0”

IO’O” T-F

773.4

4,300

—

—

6’0”

5’6T-F

573.8

1,600

Pilot unit 1mm book/year

2. Equipment as designed facility

DEZ Vaporizer Duty, BTU/hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . 105,000 141,000

DEZ 1st Stg. Condenser

Duty, BTU/ hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120,000 152,500

DEZ 2nd Stg. Condenser

Duty, BTU/hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17,000 23,000

N2 Heater/Cooler

Duty, Heating BTU/hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17,500

Cooling BTU/hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20,000

50,000

54,000

Dehydration Water Heater

Duty, BTU/hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92,670

Kw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Watlow Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FPN720G5

288,178

100

FRN744E5

Hot Oil Heater

Duty, BTU/hr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130,000

Kw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Watlow Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CFRS743E5

151,000

50

CFRS751 E5

Refrigeration Unit

Duty, Tons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DEZ Receiver

Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dehydration Tank

Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hot Oil Surge Tank

Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chilled Oil Surge Tank

Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11 15

12.09”

30”T- T

17.25”

36”S/S

24”OD

18”

24”OD

50”

23.25”

4’O”T-T

35.25”

4’6”T-T

29.25”

4’O”T-T

35.25-ID

5’O”T-T
115

Table C-3.—Equipment Changes for Scale-UP—(Continued)

Pilot unit 1 mm book/year

2. Equipment as designed facility

Seal Pot

Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Exhaust Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Discharge Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ACFM Suction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Balzers - Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,.

DEZ Recycle Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Discharge Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ACFM Suction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Balzers Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

12.75’OD

18”T-T

(Balzers)

40 Torr

800Torr

128

DUO250A

(Two Stg.

Rotary Vane)

(Balzers)

18Torr

50Torr

1,505

WKP4000

2

18”OD

18”T-T

(Balzers)

140Torr

800Torr

110

2CDU0250 A

(Balzers)

18 Torr

150 Torr

2,610

2@WKP4000

Nitrogen Recycle Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Not Provided)

Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0Psig 0 Psig

Discharge Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Psig 15 Psig

ACFM Suction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 1,050

Chamber Vacuum Pump

Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....Oil to760Torr Oil to 760 Torr

Discharge Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 Torr 800 Torr

ACFM Suction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 170

Kinney Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . KTC-112 3@ KTC-225

Hot Oil Circulation Pump

GPM, Rated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67.0 200

TDH, Rated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.5’ 100’

H.H.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.25 4.17

Chilled Oil Circulation Pump

GPM, Rated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.5 270

TDH, Rated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88.9’ 100’

H.H.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.23 6.12
Appendix D

Suggestion for Standard Paper Testing

for Deacidification Quality Control

by National Bureau of Standards

This appendix lists procedures recommended for

assessing the stability of book papers before and after

treatment with diethylzinc. The procedures were recommended by Edwin Parks of the National Bureau of

Standards Ceramics Chemistry and Bioprocesses

Group. The appendix consists of two parts:

1.

2.

List A consists of routine tests suitable for quality

control during the engineering program. With the

exception of fiber strength analysis by zero span

tensile testing, most of the tests have been used by

the Library of Congress in their development of

the diethylzinc process. One modification of an

aging technique is recommended, that is, humid

aging at 750 C and 50 percent relative humidity.

List B consists of more time-consuming research

tools that may not be practical in the context of

a large-volume testing program.

Technology for Assessing the

Effectiveness of Paper Preservation by

Treatment With Diethylzinc (DEZ)

Recommended Procedures

1. Accelerated aging techniques (to be performed be2.

fore and after DEZ treatments) -

a.

b.

Dry air

“Standard test method for relative stability of paper (effect on folding endurance). ” ASTM Designation D-776-65

Humid air

(1) 75° C, 50 percent relative humidity

(2) 90° C, 50 percent relative humidity

Commercial ovens may be employed, combining

wet bulb temperatures of 59.5 and 730 C and dry

bulb temperatures of750 C and 90° C, respectively.

Aging periods and sampling intervals to achieve significant decreases in strength will vary with types of

paper. Twelve days is likely to be more than

sufficient.

Testing procedures (to be performed before and after accelerated aging)

a. Folding endurance

“Standard test method for folding endurance of

paper by the MIT tester. ” ASTM Designation:

116

b.

D-2176-69. Method allows for pressures of 0.5 to

1.5 kg, but even the lowest pressure may be too

severe for deteriorated book papers.

Fiber strength (zero-span tensile strength)

c.

d

Not a standard procedure. Zero-span tensile tests

can be performed with an IPC (Institute of Paper

Chemistry) zero- span clamp attached to the jaws

of a conventional load-elongation machine. However, we recommend a machine dedicated to zero

span tensile determinations,

This is a quick, simple physical test that may

be applicable to degraded book papers which

would not survive even a single fold, but might

still have useful life if the DEZ method prevents

further degradation.

Hot water extractable acidity or alkalinity of paper. TAPPI method T-428 pm-77. Modifications

of the standard method, as proposed by the Library of Congress, should be equally suitable for

the extensive routine testing program envisaged.

, Brightness of pulp paper, and paperboard (directional reflectance at 457 mm). TAPPI standard

Method T-452 em-83.

Supplemental Procedures

1.

2.

3.

Standard test method for copper number of paper

and paperboard. ASTM Designation: D-9 19-74.

A suggested research technique only, not for routine qualitative assurance testing. This is thought to

be a measure of carbonyl group concentration and

may be correlated with carbonyl absorbance peak intensities in FTIR spectra. The prospect might then

exist to use FTIR as a quick, non-destructive routine test.

Wet tensile breaking strength of paper and paperboard. TAPPI method T-456 em-822. For research

and exploratory purposes only.

Alpha cellulose in paper. TAPPI method I-429 os78. Alpha cellulose is a stable polymeric component

of paper. This procedure uses strong alkali to extract

components of less stability and lower molecular

weight; hence, it is potentially useful for following

the course of depolymerization during aging processes. A time-consuming and hazardous procedure

to be used for specific research objectives, not as a

routine test; not useful for papers containing lignin.
Appendix E

List of Papers and Presentations on the

DEZ Process by the Staff of the Library of

Congress From 1974-86

George B. Kelly

1974

‘ ‘Research on Mass Treatment in Conservation’

1978

‘ ‘Mass Deacidification With Diethylzinc, LargeScale Trials”

“Inhibition of Light Sensitivity of Papers Treated

With Diethylzinc”

1979

“Non-Aqueous Deacidification: Treatment en masse

and for the Small Workshop’

1980

“Non-Aqueous Deacidification: Treatment en masse

and for the Small Workshop

‘ ‘Mass Deacidification With Diethylzinc’

Donald K. Sebera

1980

“Current Problems in the Conservation of Cellulosic

Materials’

1983

“Recent Developments in the Library of Congress’

DEZ Mass Deacidification Process”

1984

‘ ‘Reactions of Diethylzinc With Paper Constituents’

1986

‘ ‘The DEZ Mass Deacidification Process at the Library of Congress’

“The DEZ Mass Deacidification Process at the

Libary of Congress’

‘ ‘The Library of Congress Mass Deacidification

Process’

Published: Bulletin of the American Institute for

Conservation, vol. 14, No. 2

Published: Preprints - AIC 6th Annual Meeting

ACS Advances in Chemistry Series 193, Preservation of Paper & Textiles of Historic and Artistic

Value #2

Rutgers University

International Conference on the Conservation of Library and Archive Materials and the Graphic Arts

Published: The Library Scene

Gordon Research Conference, Wolfboro, NH

American Institute for the Conservation of Historic

and Artistic Works of Art on Paper, Baltimore, MD

Third Symposium on the Preservation of Paper and

Textiles of Historic Value, American Chemical Society, Philadelphia, PA

10th Annual Conference of Institute of Paper Conservation, Oxford, England

Paper submitted for publication in Studies in Conservation

Paper prepared in response to George Cunha’s questionnaire

117
118

Peter G. Sparks

1982

Library of Congress’ Mass

Library of Congress’ Mass

Deacidification/Optical

Deacidification/Optical

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

1983

Library of Congress’ Mass Deacidification Program

1984

Library of Congress’ Mass Deacidification/Optical

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

1985

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

1986

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Mass Deacidification Program

Library of Congress’ Deacidification Program

Library of Congress’ Mass Deacidiflcation Program

Library Directors Meeting- May 6

Library of Congress Technology Meeting-June 17

NASA/Press Briefing- October 15

Fifth Brazilian Conference on Deacidification

Program

IFLA Conference - August 26

ALISE - January 7

COSLA - April 11

Senate Committee Hearing - April 11

Simmons College - April 18

Society of American Archivists - August 31

Book Publishers - September

NASA/Goddard Space Flight Center

Federal Interagency Field Program Workshop -

November 29

University of Puerto Rico - February 5

National Conference on Museum Security -

February 18

IFLA - Vienna Conference on Preservation of

Library Materials - April

LITA Institute on Technology - May 6

Special Library Association Military Division -

May 8

Frederick City Council Meeting - May 8

ALA Law Librarians - July 8

Institute on Federal Library Resources - July 22

Library Binding Institute - October 27