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U. S. DEPARTMENT OF COMMERCE

R. P. LAMONT, Secretary BUREAU OF STANDARDS

GEORGE K. BURGESS, Director

MISCELLANEOUS PUBLICATION, BUREAU OF STANDARDS, No. 128

A SURVEY

OF STORAGE CONDITIONS IN LIBRARIES

RELATIVE TO THE PRESERVATION

OF RECORDS

By

ARTHUR E. KIMBERLY

J. F. G. HICKS, jr.

OCTOBER 5, 1931

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1931

For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents

M 128

A SURVEY OF STORAGE CONDITIONS IN LIBRARIES

RELATIVE TO THE PRESERVATION OF RECORDS 1 By Arthur E. Kimberly 2 and J. F. G. Hicks, jr. 2

A survey of leading present-day libraries was undertaken in order to determine the extent to which conditions of storage may be responsible for the deterioration of records and other material stored in libraries. The

inspection stressed particularly conditions within the book stacks relative

to the control of temperature, humidity, and air pollution, as well as the

exclusion of light, all of which are recognized as important factors.

It was found that while the effects of light and dust were well guarded

against in general, no library was able to control completely the variation

of temperature and relative humidity within the narrow limits considered necessary for successful preservation of records and none attempted to mini- mize acidic pollutions of the air. In view of the conditions found, as a result of this survey, and of corro- borating laboratory experiments, optimum conditions of air purity, temperature, and illumination considered desirable for preservation of records were

formulated, and means of obtaining them suggested.

I. EXTERNAL DETERIORATING AGENTS

The permanence of paper is affected by two distinct groups of

factors—one, the " internal " agents of deterioration or those substances produced or left within the paper by the method of manufacture ; the other, the " external " agents of deterioration or the

factors which are introduced by the conditions of use and storage

of the finished paper. In order, therefore, to obtain some indication

of the extent to which these external agents are responsible for the

deterioration of books stored in libraries, a survey of storage conditions in present-day libraries was undertaken.

The preliminary step in such a survey was the definition of the

external agents as set forth by the literature. As early as 1881,

Girard 3 pointed out that cellulose, the principal constituent of paper,

1 This is one of a series of investigations concerning the preservation of written and

printed records, which is being made at the National Bureau of Standards with the

assistance of a fund granted for the purpose by the Carnegie Corporation to the National Research Council.

2 Research associate, National Research Council.

8 A. Girard, Ann. chim. phys., [5] 24, p. 337; 1881. 75193°—31 1

ABSTRACT

CONTENTS

Page

I. External deteriorating agents

II. Method of inspection

III. Results

IV. Discussion of results V. Recommendations

VI. Summary

VII. Acknowledgment

122

4

778
2 NATIONAL BUREAU OF STANDARDS

is readily attacked by acids and that the resulting product is further

degenerated by contact with air. Later workers 4 5 confirmed his

statements and indicated other important factors in the deterioration

of paper. Further perusal of the literature shows the following

external agents to> be of consequence in any consideration of paper

preservation.

1. Light,6 7 8 9 10 11 particularly sunlight, attacks both the paper

fibers and the sizing material, producing " yellowing " and brittling.

2. The adsorption of moisture containing sulphurous and sul- phuric acids resulting from the combustion of coal and other pres- ent-day fuels, produces marked deterioration.12 13 14 15 3. Successive changes in atmospheric temperature and relative

humidity seem to exert a marked deteriorative effect,16 17 the phenomenon most frequently observed being that of brittling following prolonged storage in warm, dry places.

4. Insects, worms, molds, and fungi also attack books in some

instances. 18 19 20 21 Since the literature indicates that the above factors influence

paper preservation, it follows that the ideal library for the preservation of records would be one in which it is possible to control or

eliminate the " external " deteriorating agents, and it was to this

ideal library that the institutions investigated were compared.

II. METHOD OF INSPECTION

Whenever possible the library in question was visited in order

to discuss with the staff the general problem of paper preservation,

as well as any difficulties peculiar to the individual library. Following this conference, a general tour of the library building was undertaken, particular stress being laid upon inspection of every phase of

illumination and ventilation, including heating. The condition of

the stored material and of the air surrounding it was also carefully

noted. In the event that a visit proved to be impossible, the in- formation desired was obtained as far as possible by correspondence,

III. RESULTS

The results of the inspection of 13 libraries suggested by the New

York Public Library are given in Table 1. The institutions in- cluded in the survey are located in the United States from the Atlantic coast to the Pacific coast and comprise both urban and country

libraries.

* W. Herzberg, mitt, kgl. Materialpriifungsamt, Berlin Lichterfelde West., Jahrg., 25,

pp. 116-119; 1907.

5 Aribert & Bouvier, La Papeterie, 42, pp. 338-352 ; 386-392 ; 1920.

e V. Schoeller, Wochbl. Papierfabr., 43, p. 3222 et seq. ; (serial) 1912.

7 P. Klemm, Papier Zt., 27, pp. 961-963 ; 1902.

S C. Schwalbe, Wochbl. Papierfabr., 38, pp. 1472-1473; 1907.

9 B. Haas, Papierfabr., 12, pp. 891 and 919 ; 1914.

10 A. B. Hitchins, Paper, 22, pp. 11-15 ; 1928. ^Kimberly and Hicks, B, S. Jour. Research, 6 (R. P. 307), May, 1931.

12 Des Voeux & Owens, The Lancet, p. 47 ; Jan. 16, 1912.

13 TL S. Bureau of Mines Bulletin No. 98 ; 1915.

14 Mellon Institute, bulletins on smoke abatement (10 in all).

15 Report, Chicago Assoc. Commerce, Smoke Abatement ; 1915.

16 O. Braums, Pulp Paper Mag. Can., 26, pp. 11, 165 ; 1928.

17 J. Norris, Library J., 38, p. 16 ; 1913.

18 W. R. Reinick, Am. J. Phar., 83, p. 503 ; 1911.

19 See Pierre, Compt. Rend., 164, p. 230 ; 1917.

20 V. Galippe, Compt. Rend., 169, p. 814; 1919.

21 Arturo Scarone, EI libro y sus enemigos, Montevideo, 217 pp. 8° ; 1917.
LIBRARY STORAGE RECORDS

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In addition to the information obtained concerning air, light, and

temperature control in the libraries visited, the following general

observations of the condition of the material stored in these institutions were made, namely

" Yellowing " was observed in hot, dry, and dusty places in the

path of direct sunlight. Books stored in diffused light seemed to be

little affected. " Brittling " was also observed under the same cir- cumstances.

Dusty papers were frequently observed to be discolored and quite

often brittle, but no general rule for the correlation of these facts

could be formulated.

No damp places were observed at the time of this survey, but

several spots were pointed out as being damp at other seasons. In

these places, the papers examined seemed soft and " fuzzy," bearing

a white powder which could readily be brushed off. They also show

brown splotches known as " foxing."

Apparently, little difficulty was being experienced with pests, as is to be expected with the precautions taken to insure cleanliness and

good ventilation.

IV. DISCUSSION OF RESULTS

An inspection of Table 1 shows that of the 13 libraries listed only

4 possessed the equipment necessary for the removal of dust from

the incoming air of their ventilating systems. Oil filters were used

in 3 of the 4 libraries attempting dust removal. The elimination of

dust from library air is very important, for dust particles, in addition to their abrasive action upon the paper and bindings of stored

material, act as nuclei for the condensation of acidic moisture. 22 Every library inspected attempted to reduce the amount of dust in

the stacks and on the books by systematic dusting. In several in- stances small hand vacuum cleaners were extensively used.

If air containing sulphur dioxide is allowed to come into contact with cotton fabric, sulphuric acid is formed upon the surface of the

substance. 23 A similar reaction would be expected in the case of

papers, since both substances are composed essentially of cellulose. This acid is not volatile at ordinary temperatures and, hence, exerts a cumulative effect throughout the life of the paper. If the paper

contains iron, as most commercial papers do, the rate of formation

of sulphuric acid from sulphur dioxide is greatly accelerated by the

catalytic effect of the iron.24 25 26 If this acid is once formed upon

the sheet, its concentration varies with the moisture content (relative humidity) of the surrounding atmosphere, the acid acting as a dehydrator in a very dry atmosphere, literally burning the paper,

while in a moist atmosphere it functions as an agent of acidic hydrolysis. The problem of air pollution is most serious as indicated by

22 Osborn Monnett, Smoke Abatement, U. S. Bureau of Mines Bull. No. 273.

28 John B. Wilkie, U. S. Bureau of Standards, Research Paper No. 294.

34 S. P. Cooke, Role of Certain Metallic Ions as Oxidation Catalysts, J. Biol. Chem., 10,

pp. 289-312; 1928.

25 L. P. Wilson, Catalytic Action in the Oxidation of Cellulose, J. Soc. Chem. Ind., 39,

p. 177T; 1920.

20 O. Baudisch and D. Davidson, Catalytic Oxidation bv Means of Complex Iron Salts,

J. Biol. Chem., 11, p. 501 ; 1927.
LIBRARY STORAGE RECORDS 5

Table 2, which shows the precipitation of sulphuric acid in tons

per square mile per year in several European and American cities. A further illustration of the quantity of sulphur dioxide present in

the atmosphere is the fact that the sulphur content (determined as S03 ) of filter oil used in a New York public library increases about

100 per cent over the original value of 0.46 per cent S03 during three

weeks' use in an oil filter. When one considers that oil filters are very inefficient as a means of removing acidic pollutants from the

air this increase assumes a position of paramount importance as an

index of conditions already at hand. Every indication of the situ- ation at present points toward .increasingly polluted urban atmospheres and in consequence an increased effect unless immediate steps are taken to minimize the amount of polluted air in libraries and

similar institutions. It is believed that such a minimization could

be effected by the substitution of a mildly alkaline solution for the

water now used in humidifying and purifying library air. Table 2.

Precipitation of sulphuric aoid m cities

TonsR~2S04

City per square

mile per

year

Glasgow i ______ 194.1 London 2 180.2

Salt Lake City i 134.0 Manchester, England 3 95.0 San Francisco 1 _ __ 83.1 Philadelphia * 83.1 Berlin 1 ___ ... _ 16.2

1 Osborn Monnett, G. St. J. Parrott, H. W. Clark, Smoke Abatement Investigation at Salt Lake City, Utah, U. S. Bureau of Mines Bulletin No. 254.

2 Des Voeux and Owens, The Sootfall of London, The Lancet, p. 47; Jan. 6, 1912.

3 Recent Progress in Smoke Abatement and Fuel Technology in Manchester, Mellon Institute, Smoke

Investigation Bulletin No. 10.

4 Data from University of Pennsylvania. Six of the thirteen libraries included in this survey possessed

machinery for humidity control, but in two cases the apparatus was

not in use at all, and in a third instance the plant was effective only

in cool weather owing to the lack of a refrigerator. An attempt was made, several years ago, to use the third-mentioned plant in the

summer, but when the advent of a spell of cooler weather precipitated the moisture from the air in the stacks upon the books stored

therein, resulting in extensive damage from molding, the attempt was abandoned. All of the equipment in full-time use was of the

water-curtain type with no means of regulating the temperature of

the water save in one instance where modern thermostatic control

had just been installed. The average library using average equipment can not control the humidity of the air within its stacks very

closely. Table 3 shows the variation of humidity in an institution

which uses oil filters and a water spray for purifying and humidifying the incoming air.
6 NATIONAL BUREAU OF STANDARDS

Table 3.Variation of relative humidity within a library

Day

Outside temperature Outside humidity

Inside temperature Inside humidity

Feb. 24 op

*50

5540

58

Per cent42

60

57

73

op

*5959

6062

Per cent38

4630

50

Feb. 25 Mar. 5 Mar. 8

Inspection of Table 3 shows a pronounced fluctuation of relative

humidity in this case, the lower limit of moisture content being below

that considered desirable for the successful preservation of stored

records. None of the libraries inspected made a definite attempt to reduce acidic pollution of the air, but those using oil filters and water

curtains reduced the acidity materially during the process of air

treatment for other purposes.

The situation regarding the protection of books from the action of

daylight is considerably better than that dealing with the other

phases of protection, for 10 of the 13 selected libraries minimize the

effect of the actinic rays of light by the total elimination of windows

in 3 cases, or by the use of thick glass in the remaining 7 examples.

In only one instance is sunlight admitted freely to the stacks, and it may be noted that excessive deterioration is apparent in this case. Book stacks, in general, were found to be lighted by small, frosted

incandescent bulbs which were switched on and off as required. This

is a very commendable practice.

The results of the survey having shown the conditions which a book stored in an average library would encounter, a series of laboratory experiments was initiated to determine the extent of the effect of each individual " external " agent of paper deterioration and to ascertain means of minimizing its action.

Rosin and other materials used in the rosin sizing of paper have

been subjected to the action of light with the result that all varieties of rosin, both bleached and unbleached, were found to be

light sensitive, darkening in color under the influence of light. 27 The presence of ferrous iron was found to accelerate this color

change materially. This is additional evidence that rosin sizing, as currently applied, is one cause of the yellowing of records with

age. Furthermore, unpublished results obtained at the bureau by

Rasch indicate that direct exposure of various types of record papers

to sunlight, for a period of only 100 hours on each side, decreased

their folding endurance from 25 to 63 per cent of the original. Both

of these findings serve to emphasize the necessity of protecting rec- ords from the destructive effects of daylight. An investigation of

the effect of air polluted with 5 to 10 parts sulphur dioxide per

1,000,000 on the various types of record papers is in progress, and

results already obtained show that 10 days' exposure to such a polluted atmosphere causes losses in physical strength running as high

as 40 percent and increases in acidity ranging from 90 to 400 per

cent. If so short an exposure as 10 days will produce an effect of

87 See footnote 11, p. 2.
LIBRARY STORAGE RECORDS 7

this magnitude, one may well wonder that publications have sur- vived as well as they have, and considering the constantly increasing

acid pollution of the air, a long further life is problematic.

V. RECOMMENDATIONS

Taking into account present library conditions and the results of

e laboratory work to date, the following recommendations as to ibrary conditions may be made

1. Daylight, particularly the actinic rays, should be rigorously

xcluded from bookstacks, either by the total elimination of windows

or so far as possible by the use of thick glass. Any necessary illu- mination should be supplied by small, frosted, incandescent iamps,

lighted as required.

2. Temperature and humidity should be automatically regulated

within relatively narrow limits. A suggested range for temperature

is 65° to 75° F., and for humidity, 45 to 55 per cent.

3. Incoming air should be purified to remove dust (oil filters) and

acidic pollutants (alkaline-water wash in scrubbers).

4. When books or other records are stored in a purified atmosphere

they should not be removed from it unnecessarily, as a short exposure

to impure air may undo the preservative measures of many years'

duration.

The machinery necessary to carry out recommendations 2 and 3

would be

1. Oil filters of a type in which the oil coating is continually

renewed.

2. Refrigerating apparatus to cool both incoming air (when neces- sary) and the solutions for the water curtains.

3. Water curtains, utilizing slightly alkaline solutions and having

thermostatic control of temperature.

4. Apparatus to heat to desired temperature purified, cold air

coming from water curtain.

In connection with air conditioning it is obvious that the installation and operation of costly apparatus is useless if members of the

library staff and others are permitted to open windows, thereby

allowing impure outside air free access to the library building. Some

difficulty of this nature may be encountered at the outset, but if the

operating conditions chosen are conducive to increased comfort, and

it is believed that such is the case with the recommended conditions,

these troubles should soon disappear. Conditioned air is coming to be used more extensively every day, not only in places of amusement

but also in industrial plants and office buildings, with increased

comfort and efficiency to all concerned.

VI. SUMMARY

1. Daylight, polluted air, variation of temperature and humidity,

and pests, are " external " agents of paper deterioration.

2. The effects of light are well recognized and guarded against

in most libraries, although one library, ultramodern in most respects,

is without protection against light.