NI8T

PUBUCATI0N8

NBSIR 75-947

FILE cort

BO NOT

COLLECTED EXECUTIVE SUMMARIES

^ STUDIES OF THE NATIONAL MEASUREMENT SYSTEM

1972-75

Raymond C. Sangster OATE '^U <^

Office of the Deputy Director

Institute for Basic Standards

National Bureau of Standards

Boulder, Colorado 80302

i

August 1976

NBSIR 75-947

COLLECTED EXECUTIVE SUMMARIES

STUDIES OF THE NATIONAL MEASUREMENT SYSTEM

1972-75

Raymond C. Sangster

Office of the Deputy Director

Institute for Basic Standards

National Bureau of Standards

Boulder, Colorado 80302

August 1976

U.S. DEPARTMENT OF COMMERCE, Elliot L Richardson, Secretary

Edward 0. Vetter, Under Secretary

Dr. Betsy Ancker-Johnson , Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

FOREWORD

The concept of a National Measurement System has, for many years,

provided a useful focus for the considerations important to physical

measurements in our technology intensive economy. Dr. R. D. Huntoon,

in his October 6, 1967, article in Science , emphasized the basis for a systems viewpoint in interrelated measurements activities and the idea

has continued to evolve. Today, we think of the U.S. National Measurement

System in terms of all the intellectual, functional and institutional

activities which involve measurements throughout our society. Moreover,

we seek to understand more completely the structural nature of this

system and its architectural needs.

There have been a number of approaches to the study of our national

system for physical measurements. The present series of studies was initiated in 1972 by Dr. Ernest Ambler, then Director of the Institute

for Basic Standards. It was Dr. Ambler's purpose to organize the essential information necessary for the effective management of NBS resources

and to promote the direct interaction between IBS staff members and the

communities of users they serve.

This document reflects the results of the intensive studies carried

out during the period from 1972 - 1975. It is important to recognize

that the National Measurement System is extremely complex having widely

distributed elements and impacts. The detailed analysis of this system

is well beyond the state-of-the-art of econometric modeling, and therefore, any study, no matter how intensive, is necessarily incomplete.

Nevertheless, the information which is now in hand provides an important

addition to our capability for planning and implementing the programs

of IBS. It also represents a growing foundation upon which we can continue our efforts to build a more effective structure.

A. 0. McCoubrey

Director, Institute for Basic Standards

National Bureau of Standards

August 1976
PREFACE

The 1972-75 Study of the National Measurement System by the NBS Institute for Basic

Standards has been a massive effort involving many people in all divisions of the

Institute. The information compiled in this document is one of the results of this

effort, and could never have been developed without the contributions of a large number

of knowledgeable individuals.

The Study was organized around a central coordinator and a group of "National Measurement System Study representatives" from the technical divisions of the Institute. The

initial central coordinator was Dr. James R. Seed, a Presidential Interchange Executive

from the Dow Chemical Company, on temporary assignment to the National Bureau of Standards.

Dr. Seed was responsible for the initial formulation of the tactical plans for this Study,

and carried the project through to the generation of a complete set of comprehensive

reports on the structure and operation of the various portions of the System, in December

1973. In August 1974, I took over the central coordinator position, and worked with the

Study representatives from the divisions of the Institute, to round out the pattern of

the Study and to develop the final reports which are being issued by NBS for the different

areas of measurement interest.

The "Executive Summaries" presented in this document were taken from the semi-final

drafts of these reports. Because this document is being published before all of the

individual reports have received final editorial clearance, there may be slight discrepancies between the summaries contained herein and those ultimately published with the

individual reports; none of these discrepancies is expected to involve any matter of

substance.

We trust that the availability of this document will be useful to many readers who

need only an overview of the results of our Study of the National Measurement System.

For those who want more detailed information about any part of this study, we have

provided a "Report Request Card" at the back of this document, which can be used to request the specific reports wanted.

At this point, it would be customary to acknowledge by name the efforts of the

secretaries and other supporting personnel without whose unstinting efforts no document

of this type could be created. However, inasmuch as these summaries were generated as parts of a large number of reports, it seems most appropriate not to attempt to acknowledge

these contributors by name, but simply to salute the devoted efforts of the secretaries

and supporting staff members of the National Bureau of Standards, without which the work

of the Bureau would be impossible.

Raymond C. Sangster

August 1976

i V
CONTENTS

COLLECTED EXECUTIVE SUMMARIES

STUDIES OF THE NATIONAL MEASUREMENT SYSTEM

1972-1975

FOREWORD iii

PREFACE iv FINAL SUMMARY REPORT, STUDY OF THE NATIONAL MEASUREMENT SYSTEM 1 TRANSACTIONS MATRIX DESCRIPTION OF THE NATIONAL SYSTEM OF PHYSICAL MEASUREMENTS 5 ECONOMIC ANALYSIS OF THE NATIONAL MEASUREMENT SYSTEM 7 STRUCTURE AND FUNCTIONS OF THE NATIONAL MEASUREMENT SYSTEM 9 THE NATIONAL MEASUREMENT SYSTEM FOR TIME AND FREQUENCY 11 THE NATIONAL MEASUREMENT SYSTEM FOR LENGTH AND RELATED DIMENSIONAL MEASUREMENTS:

PART 1 13 THE NATIONAL MEASUREMENT SYSTEM FOR LENGTH AND RELATED DIMENSIONAL MEASUREMENTS,

PART 2: MECHANICAL VIBRATION AND SHOCK 15 THE NATIONAL MEASUREMENT SYSTEM FOR SURFACE FINISH 17 THE NATIONAL MASS, VOLUME, AND DENSITY MEASUREMENT SYSTEM 19

THE NATIONAL FORCE MEASUREMENT SYSTEM 21 THE NATIONAL MEASUREMENT SYSTEM FOR FLUID FLOW 23

THE NATIONAL MEASUREMENT SYSTEM FOR PRESSURE 25

THE NATIONAL TEMPERATURE MEASUREMENT SYSTEM 27 THE NATIONAL HUMIDITY AND MOISTURE MEASUREMENT SYSTEM 29 THE NATIONAL MEASUREMENT SYSTEM FOR THERMODYNAMIC PROPERTIES OF FLUIDS 31 THE NATIONAL MEASUREMENT SYSTEM FOR CRYOGENICS 33 THE NATIONAL MEASUREMENT SYSTEM FOR ELECTRICITY 35 THE NATIONAL ELECTROMAGNETICS MEASUREMENT SYSTEM 37

THE NATIONAL MEASUREMENT SYSTEM FOR MEDICAL ULTRASONICS 39 THE NATIONAL MEASUREMENT SYSTEM FOR ACOUSTICS 41 THE NATIONAL MEASUREMENT SYSTEM FOR RADIOMETRY AND PHOTOMETRY 43 THE NATIONAL MEASUREMENT SYSTEM FOR SPECTROPHOTOMETRY 45

THE NATIONAL MEASUREMENT SYSTEM FOR FAR ULTRAVIOLET RADIOMETRY 47 THE NATIONAL MEASUREMENT SYSTEM FOR OPTICS 49 THE NATIONAL MEASUREMENT SYSTEM FOR THE PHYSICAL PROPERTIES OF ATOMS AND MOLECULES ... 51 THE NATIONAL MEASUREMENT SYSTEM FOR SURFACE PROPERTIES 53 THE NATIONAL MEASUREMENT SYSTEM FOR IONIZING RADIATION 55

LIST OF TABLES

Table 1. Direct measurements transactions matrix for IBS Study of

National Measurement System . 3 Table 2. Direct measurements transactions matrix for outputs of NBS 4

V

NBSIR 75-925

FINAL SUMMARY REPORT

STUDY OF THE NATIONAL MEASUREMENT SYSTEM

Raymond C. Sangster

NBS Institute for Basic Standards

March 1976

EXECUTIVE SUMMARY

The National Measurement System consists

of all of the activities and mechanisms--

intellectual and operational, technical and

insti tutional --that provide physical measurement data to allow the creation of the objective, quantitative knowledge required by our

society. These data are used to describe,

predict, communicate, decide, control, and

react, in many aspects of our personal lives,

society, science, and technology.

The system model has five levels:

I. The conceptual system , the intellectual foundation that defines the measurement

quantities and units.

I I . The basic technical infrastructure

that provides the tools and techniques and

agreements that allow the conceptual system

to be reduced to practice. Component parts

include the documentary specifications system, measurement instrumentation (including

software), and reference materials and data.

III. Realized measurement capabilities , i.e., abilities to measure specific quantities to known accuracies under defined con- ditions.

IV. The institutional dissemination and

enforcement network ; components include NBS, state and local weights and measures agencies, standards laboratories, and some regulatory agencies.

V. End-use measurements , which all other

levels of the system exist to support.

Supporting all of these levels is a central pillar of measurement science, know-how,

and trained people.

Interactions among different institutional

sectors of the system have been described by

a direct measurements transactions matrix.

Table 1 is the summary matrix developed by

this study. Table 2 describes NBS outputs.

A macroeconomic study of the measurement

system was based upon analyses of what people

actually do on the job. The U.S. economic

input-output tables provided insight into

measurement instrumentation costs. The making of physical measurements is

ubiquitous. All 78 major industrial sectors,

all levels of government, and consumers

bought measurement equipment or labor.

Measurements cost an estimated 6% of GNP. About 85% is for labor.

Federal, state and local governments are the largest user sector, about 30% of total.

Other service industries, principally

trade, utilities, transportation and communication, account for about 25%.

"High technology" manufacturing industries

spend a larger share of their value-added but

relatively few dollars.

Economics consultants from the University

of Colorado and George Washington University

contributed to the study. Measurement is

part of the knowledge or information economic sector, where economic analysis is in

its infancy. Preliminary correlations of

measurement intensity with economic growth

and productivity data for major industrial

sectors reveals a significant positive correlation. Firm cost-benefit analyses are generally lacking and are difficult to effect

Microstudies of the system were conducted

in the following technical areas: Time & frequency Electromagnetics

Length & related dimen- MedicaT ultrasonics

sional measurements Acoustics

Vibration and shock Radiometry & Surface finish photometry

Mass, volume & density Spectrophotometry

Force Far ultraviolet

Fluid flow radiometry

Pressure Optics

Temperature Lasers

Humidity & moisture Physical properties

Thermodynamic properties of atoms & moleof fluids cules

Cryogenics Surface properties

Electricity Ionizing radiation

In general, the U.S. national measurement

system is doing its job adequately, at rea- sonable costs. For instance, in the basic

areas of measurement of time, length, and mass, the system is well under control; the

changes that are occurring are often very

dramatic, but their focus is on economics:

making new tasks economically feasible and

allowing old ones to be done less expensively

Examples include dissemination of time signals by satellite, electronic distancemeasuring equipment for surveying, and automated digital grocery store scales.
The most significant systematic problem

is the lack of adequate mechanisms for quality assurance in the system. There is a widespread need for more "how-to" information at the working level. Inversely, NBS

and other infrastructural institutions are

not always aware of the real needs of the

system.

Specific areas of deficiency include several in which essentially no national mea- surement system exists: Surface properties

(of importance in such diverse areas as cat- alytic petroleum refining and microelectronics), because the field has blossomed so dramatically so recently. Medical ultrasonics

(used for detecting cancer and monitoring the

unborn), which has also blossomed very dramatically. Far ultraviolet radiometry (of

importance in phototherapy of newborn infants

and for monitoring the earth's shielding

ozone layer), because standards capabilities

have evolved only recently. Spectrophotometry (of importance in all fields of color

and appearance and lighting), because inadequate national leadership has existed until

very recently.

Further, there are several areas in which

the measurement system will be subjected to severe strains in the foreseeable future,

unless appropriately responsive steps are taken during the next several years. The

most dramatic of these is the measurement

system needed for the safeguards program for

special (fissionable) nuclear materials.

Less dramatic problems exist in other areas

of governmental regulation, such as environmental protection and occupational safety

and health, and control of noise pollution.

Other areas in which improvements in the

system are needed include the following:

1. A firm base for measurement under

dynamic, time-varying conditions, of force,

fluid flow, pressure, temperature, humidity,

electrical quantities, and others.

2. Similar needs for measurements made

under hostile environmental conditions, such

as the measurement of temperature, pressure,

neutron flux, and fission rates inside

nuclear reactors.

3. Precision characterization of many

kinds of measurement transducers, especially

for temperature and pressure,

4. Non-contacting, on-line, manufacturing

instrumentation for measurement of surface

finish parameters.

5. Flow measurements in the field, such

as low air velocities for mine ventilation,

water supply and waste water flows, metering

of natural gas, and multi-component flow.

6. Measurement assurance for auto tire

pressures and aircraft altimeters.

7. Electronic medical thermometry.

8. Measurement of moisture in grain.

2

9. Gathering and predicting measurement

data on the thermodynamics of fluids, especially complex mixtures.

10. A measurement system and data for

liquified natural gas, hydrogen as a fuel,

and superconductivity in the electrical

power industry.

11. Standards support to high speed,

dynamic, automatic measurement systems, in

electronics and electromagnetics.

12. Widely available techniques for

measurement of electromagnetic interference

and susceptibility phenomena.

13. Widely available 1% end-use measurements in radiometry and photometry, where

20% is common today.

14. Improvement of measurement of ionizing

radiations used in medicine, to which workers

are exposed, or present in the environment.

The major trends of the System are these:

Increased complexity, resulting from the

ever-increasing scope of science and technology, from the development of the information

economy, and from the challenge of mastering

the ever-growing complexity of our society.

Increased integration, to meet the need

to provide most economically and effectively

the measurement data required by our society.

Improved quality control, and

Improved information resources. Automation, to apply the computer to relax the limitations imposed by the

inadequacies of human beings.

Metrication, to bring the U.S. into line

with the rest of the world.

Consolidation of the scientific revolution

in the basis of the system that has occurred

since World War II. As the central measurements standards

institution in this country, NBS contributes

to every aspect of the National Measurement

System. Its two primary unique functions are custody of the national standards of physical

measurement and promotion of the health of

the entire National Measurement System.

Specific services rendered to the System include measurement services (calibration

services, Measurement Assurance Programs,

time and frequency broadcasts, consultation

and advice, and others), technical data,

standard reference materials, coordination

services, technical information services, and

direct technical assistance to other agencies,

public or private, while being responsive to current national concerns.

NBS is currently responding to most of the

measurement system needs identified by this

study. The major challenge facing the Bureau

is that of wise deployment of constant or shrinking resources to support the needs

of a constantly expanding National Measurement System.
Table 1. Direct measurements transactions matrix for IBS Study of National Measurement System.

DIRECT PCASUREICKTS TUAHSACTIONS

I«TI1IX FOR WTIONAL SYSTEM

OF PHYSICAL «ASUR£MENTS

(March 1976)

U

S

ER

S

z Xj O -D »0

INTtRNATlONAL

rv

HETROLOGICAL

ORGANIZATIONS

1

. i

3

INSTRUMENTATION

*

INDUSTRY (SIC

Major

Gp

30)

N

B

S

OTHER

U.S.

NATIONAL

STANDARDS

AUTHORITIES

5TATC J

LOCAL

OFFICES

OF

HEIGHTS

d

MEASURES

(OWM's)

STANDARDS

&

TESTING

CO

LABORATORIES

AND

SERVICES

REGULATORY

>o

AGENCIES (excl.

OWM's) 3

^

is?"

CIVILIAN

FEDERAL

^

GOVT

AGE

N(

Its

(exc.

Stds

Labs

S

Req.Aq.

)

STATE

S

LOCAL

~

GOV'T

AGENCIES

(exc.

OUM's

&

Reo.

Ao.)

INDUSTRIAL

S

TRADE

AS.SOCIATIONS

~

^ o m

^ Z Q

5 — u^

14 ^

CONSTRUCTION

(SIC

Div.

C) 2 o

o a! —

3 g on

1

6

CHEM/PETROL/RUBBER/

:i

STONE/CLAY/GLASS.

.

.

(SIC

28-30,

32)

PRIMARY

S

FAB.

S

METAL

PRODUCTS

(SIC

33-34,

391)

MACHINERY

S

EXCEPT

ELECTRICAL

(SIC

Major

Gp

35)

ELECTRIC

AND

g

ELECTRONIC

EQPMT

(SIC

Major

Gp

36)

TRANSPORTATION

EQUIPMENT

(SIC

Major

Gp

37)

TRANSPORTATION

H

~

PUBLIC

UTILITIES

(SIC

Div.

E)

i S "

u- > 5 lis

23 ^,

HEALTH

SERVICES

"

(SIC

Major

Gp

80)

S

GENERAL

PUBLIC

1 KNOHLEDSE

SUPPLIERS

COMMUNITY \

( Sci cncs I EduCdti on

,

Prof. Soc. S Publ.

r-r

6 2

3 1 2

1

5 1 3

1

2 1 3

1 T~r

4

2

1 1

2 1 2

1

3 1 2

2

3 1 3

1

3 2 3

2

2

1

1

2 2

1 2

1 1 J—

T

1

1

3 1 2

1

3 1 2

1

2 1 2

1

3 2

3

1

3 1 3

1

2 1 2

2

3 1

1

1

2 1

1

1

2 2

1

1 2 INTERNATIONAL 2 1

1

1

3 1 3

1

3 1 2

2

2 2

1

1

3 1 3 2

1 1 1 1 1 1 1

3 2

1 2

h—

r

2

2

3 2

1

3 1 3

1

3 1 2

2

3 1

1

1

3 1 2

3 2

2

2

3 1 2

1

2 1 2

1

1

3 1 2

2

1 2 2

2 1 2

1

2

2 1 2

1

2 1 2

1

2 1 2

1

3 1 2 2

1 2 1

SiC Kaior Go 38)

2 1 2

1

2 1

1

1 ^'2

I—

T

5

3 1 3 1 1 3 1 3 3 1 2

2

3 1 5 23 1 4 3

2 1 2 3 1 3

2 4

3 1 3 2

3 113 1 ,^ 1/

3 1 5

1

3 1 5

i

3 1 5

1

3 1 53 1 5

1

3 2 4

2

3 1 4

2

5 NBS

3 1 3

1

3 1 3

2

3 1 3

2

3

2 4

1

3 1

1 4 1 2

2 f-T

3

1

3 2

2

1

3

3 3

2

2 1

1

1

2 2

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1 .

1 2 21

1

2 2 2

2

4 2 2

2

2 1 2

1

3 1 2

1

4 1 2

1

4 2

2

2

4 3

1 2

4 3

2

2

2 1

1

1 6 OTHER U.S. NATIONAL

1 1 1 3 1

1 3 11

1

1 1 2 1 1 1 1 1 1 1

1

1

1 T" T

1

1 R

7" 1 2

-

1 R

4

1 1 3 11

1

1 1 3 1 2

2

1

3 1 2

1

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4

3

1

3—

r

1

1 6 i "estins 2 1

1

1

2 1 2 2 1 3

1 R

3 1 2

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3 1 3

1

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3 1 3

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3 1 2

1

1

3

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1 1 1 2 1 2

1

3 1 23

1

1

3 1 2

1

3 1 3

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3 2 2

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3 1

1

)

3 2

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1 2

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3 2

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3 2

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2 1

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1 R

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4 2

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4 1

1 2 R

4 2

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3 1 2

1 R

3 1 2

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4 1 2

3 2 2

1 R

3 1 2

2 R

3 1 2

2 R

3 1 2

2 R

4 2

2

3 R

3 1 2 2 R 10 -A DEFENSE

(excl. Stds. Labs)

3 2 2

2

3 1 2

1

3 1 3

2 R M-3

1 R

1

3 1 3

1 R

1

i T 3 1 22 1

1

1

2—

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1

1 R

3 1 2

1 R

3 1 2

R

3 1 4

2 R

3 1 4

2 R

2 1 2

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2 R

1 R

11 CIVILIAN FEDERAL

GOV'T AGENCIES (eicl. Stds. Labs S Req. Ag.) 1 1

2 1 2

2

2 1 2

2

3 1 3

1

1

2 2 2

1

2 1 2

2 1

7 2_

2 1 2

1

2 1

1 2

2 1 1

2 2

2

2

3

2

1

3 1

1

1

3 1 2

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3 1 2

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4 1 4

1 2

2

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12 STATE t LOCAL GOVERNMENT AGENCIES

(exc. OWM's S Req. Aq.)

1 1 1 R

2 1

1

1 R

1 1 R R

1 1 3 2 6 1 1 2 1 1 1 1 1 1 1 1 U iNbuSTSlAL TRADE ASSOCIATIONS

2

1

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2 1 2

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2 1 2 13 1 2 1 2 2 \

1

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1 2 2 r-r2

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1 1 1

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FISHING; MINING

(SIC Div. A S B)

1

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1 1 R R

1 2 1

2 5 1 2 2 2 1 1 2 1

CONSTRUCTION

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1

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1

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1 1 1 6 1 R

1 1 1 1

16 FOOD/TOB/TEXTILE/ APPAREL/LBR/FURN/PAPER/

LEATHER (SIC 20-26, 31)

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1

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1 2 R

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3 1

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1 1 3 1 2

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1 1

2 1 6

J

1 R

1 R R

1 R

2

17 CMEM/PETBOL/IIUBBEI!/ PLASTICS/STONE/CLAY/ SUSS (SIC 28-30, 32)

2 1 2

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1 1 1 1 1 1

18 OOI'VIO' i =SB.

:S:;"33-3i:'391l

2 1

1

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2

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1 31 2

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2 1

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19 WCrtlNERY.

EXCEPT ELECTRICAL

(SIC Maior Go 35)

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1 2^^

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'..'.:':•<:: ;3pkt

=;: S? 36)

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1 2

3 1 3

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1 1 1 I 1 2

3 T

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,

2 2

2 2 2

2

EOLlPKEfiT (SIC Major Gp 37;

2 2 1 2

1

3 1 2

1 R

2 1 2

2 R

2 1 1%2 1 2 22 1 2 22 1 2

1

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1

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1 1 1 1

2 1

1

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2 1

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1

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1

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1

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R

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2 1 1 1 1 1 2 2 2 1 2 7 1 6

^* HEALTH SERVICES

(SIC Major Gp 80)

1 1 2 R

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2

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25 GENERAL "UBLK 1 P

2 p

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1 R

2 1

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1 R2

R R

1 R

1 R

1 R1 R

1 R1 R R R1 R2 R2

R

1 R

5—

r

7

1

KEY TO MATRIX ENTRIES

C - IMPORTAi'CE OF TRANSA CT I ONS

1 = Purely convenience

2 = Strongly desirable

3 = No real alternatives

4 = Essential

B - RATE OF CHANGE

N = Declining

0 = Stable

2 = Growing

4 = Growing explosively

R = Flow of requirements info' dominates

D - (IN)ADEQUACY OF SERVICES

No improvements needed

Could be improved

Margi nal Serious deficiencies

Out of control

- MAGNITUDE OF TRANSACTIONS

0 = Trivial

1 = Minor

2 = Moderate

3 = Important

4-7 = Major

3
Table 2. Direct measurements transactions matrix for outputs of NBS. *

DIRECT fCASUREMENTS

TRANSACTIONS

MATRIX FOR OUTPUTS OF NBS

U

S

ER

S

KNOWLEDGE

COMMUNITY

(Science,

Education,

Prof.

Soc.

S

Publ.)

INTERNATIONAL

METROLOGICAL

ORGANIZATIONS

DOCUMENTARY

"

STANDARDS

ORGANIZfTIONS

INSTRUMENTATION

INDUSTRY

(SIC

Maior

Go

38)

N

B

S5

OTHER

U.S.

NATIONAL

STANDARDS

AUTHORITIES

STATE

8

LOCAL

OFFICES

OF

WEIGHTS

8

MEASURES

(OWM's)

STANDARDS

8

TESTING

»

UBORATORIES

AND

SERVICES

1

REGULATORY

AGENCIES1

(excl.

OWM's)

DEPARTMENT

OF

S

DEFENSE (excl.

Stds.

Labs)

CIVILIAN

FEDERAL

-

GOV'T

AGENCIES

(exc.

Stds

Labs

8

Req.Aq.) 1^

12

INDUSTRIAL

S

TRADE

ASSOCIATIONS AGRICULTURE,

FORESTRY

S

FISHING;

MINING

(SIC

Div.

A

8

B)

_

-

CONSTRUCTION

(SIC

Div.

C)

FOOD/TEXTILE/LBR/

S

PAPER/LEATHER/ETC.

(SIC

20-26,

31) is-

^ o

lil

17

PRIMARY

8

FAB.

a

METAL

PRODUCTS

(SIC

33-34.

391)

MACHINERY

S

EXCEPT

ELECTRICAL

(SIC

Major

Gp

35)

ELECTRIC

AND

S

ELECTRONIC

EQPMT

(SIC

Major

Go

36)

TRANSPORTATION

EQUIPMENT

(SIC

Major

Go

37)

TRANSPORTATION

8

K

PUBLIC

UTILITIES

(SIC

Div.

E) Z .—

o ^ o

23

HEALTH

SERVICES

(SIC

Major

Gp

80)

S

GENERAL

PUBLIC

MEASUREMENT SECTOr\^

1 TIME « FREOUENCY

2

3

3 1 43 1 3 4 3

3 1 2

I

3 1 33 33 ? 4 3 1 4 1 1

3 1 4 3

2

3

2 LENGTH S RELATED DIMENSIONAL MEASUREMENTS

1 1

1

3 1 4

2 1 2

2

3 1 3 3

3 1

1 N

3 1 4 1 1 3. 4 1 4

2

1

3 ^ 3i 1 4

3 1 43 1 3

2

3 1 3 N

1

3 1

1 N

1 1

1

^ VIBRATION i SHOCK

3 2 2

?.

2 3

1 2

2 2

2

2

2 2 2 1 2

2 1 2 13 1

1 N

2 1

1 2

2 3

1

2 3

1

3 2

2

1

2 2

1

2 3

1

4 SURFACE FINISH

3 1 2

?

3 2 2

2

3 1 3

2

2 1 2 23 1 2

3 1 2 22 1

1

3 1 2 2

1 2

2 ^

1

2 1 22 1 2

3 2

2

2

2 1

1 2

2 2

2

5 MASS, VOLUME 8 DENSITY

4 1 4

4 1 4

3

2 1 3

2 I 2

1

3

4 1 4

2

2

2

3 1 3

1 2 N

2

1

2

1

1

2 2

1

2

1 ^2

1

1

2 1 2

1

1 2

N

6 FORCE

2

3

2 42

3 2

3

3 4

1

1

3

3

3

3 2

1 4

N

2 4

2

3

1 2

1

1

1

1

1 2] 21 2 3 21 21 2 21

7 FLUID FLOW

2 1 3

?

2 3 3 2

3

3

3

3

2

3

3

3 32 1 2 22

2

y 1 2

2

2

2 1 22 1 3

o r 2 1

8 PRESSURE3 2

1

3 2

1

1

3

2

2

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4

3 1 .

3 1 2

3

2

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1

2 1 2

1

1 1 2

1

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1

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^ 1 4—

T

4

1

4—

T

4

1

1 1

1 9 TEMPERATURE

3 3 34 2

3 2

2 1 3 ?2 3

3

?

2 3

3 ?

2 1

1

?.

2 3

3

2

2 3

2

2

2 3 3 3 2

2

2

2

2 1 2

2

2 1 3 2

3

2

2""

T' 3

2

"2"""

1 3

2

3

2

2

2

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'"humidity S moisture

2 1 2

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2

3 1 32 1 23 3

2

2

3 3 3 1 3

2

3

2

1

2 1 22 2

1

3 1 2 1

11 THERMODYNAMIC

PROPERTIES

OF FLUIDS

4 2

3

1

4 1 3

?

4 2

3

1

3 1 3 2

^

3

1

3 1 2

2

2 2

2 3

3 1 4

1

3 2 4

3

2

2 2^2

3

1 2X 3 3

1 2

2 1

1 2

2 1

1 2

2 2

2

2 12 CRYOGENICS

4 1 44 1 2 24 1 3 23 1 3

2

4

2

1 2

2 2

2

2

1 4

2

4

2 1 2 4

2 1 3

2

2 1 3

2

2 1 3

2

1

1 2

1 ? ELECTRICITY

3 2

3

3

3 1 3

2

2 1 3

3

4 1 4

3

4

3

1 4

2

3

3

2

2 w32

2

2

2

2

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•

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1

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2 14 ELECTROMAGNETICS

3 2 4

?

3

1

2

1

4

1

4

1

4

1

2

1

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1

1

1

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1

3

1

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1

'^MEDICAL

ULTRASONICS

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2

.3

2 2

4

2

2

2

3

1 3

2

1

2 1 2

1

3 2

1 2 ^^ACOUSTICS

2 2 3

2 1 3 3 3 2

1

4

^

1 2

3 2 3 2 1 2

2 1 3

I

2 3

1 2

2

''radiometry 8 photometry

4

2

3 ^ 3

2

3 24

2

3

2

4' 2

2

2 N

3

2

4

2

1 4

2

5

1 2 18 SPECTROPHOTOMETRY 2 X 2

2

2

?

2

2 2

2

?

2 1 2

2

] 1

1

2 3

2 21 2

2

2

4

2 3

2 2

2 3

2 2

2 3

2

2

2 3

2

2

2 3

1 2

^

2

^

2

2 1 2

2 ''far ultraviolet

raoiometry

2 2

3

1

2 3 3

2

2 2

2 2

4 2 2

2

2 2

2

2

2 3

3

2

2 2

1

2 3 32 2

1 2

2 2

1 4

2 3

1 4

2 2

1 4 20 OPTICS

2 1 22

2

1

3 1 33 1 2

1

1 N

4

3

3 1

1

4

3

4 1 2 12 1 2 1

4

4

4

2

4

4

2 1 3 2 1

1

1

1

21 LASERS

4

3

4

2

4

3

4 2

4 4 2

4

4

4

4

4

4 1 1

4 2

4 4 2

3 3 3

22PHYSICAL PROPERTIES

OF ATOMS S MOLECULES

3 4

3

2

2

2

3 4

4

3 4

2

3 4

2

3 3

3

3 4

2 23 SURFACE PROPERTIES

4 1 3

3 1 2 23 2

2 2

3 2

3

2

2 2

1

2

3 2

3

2

3 2

2

2

3 2

3 2

; 2

3

3 2

3

3 2

3 ? 24 IONIZING RADIATION

2 1 3

3 2 4

?

3 3 4

3

3 1 4

3

4

3 3 3 2

3 3 4

3

3 2 34 3 4 i

4 3 3S 2

3

2 i

2

1

2 J 4

2

2

4

^ 5 4

3 J—

T

4

4

4 4

3 3

4 3 4

2

1

1

25 AVERAGE

3 1 3

1

3 1 3

2

3 1 3 23 1 3 i.3 1 4 1

3 1

1

4 I 2 i.

3 1 3

1

3 2

2

1

3 33 1 32 1

1

1

2

2

4 1 2

1

1

J—

r

1

1

J 2

2

2

4 2

2

2.

2 1 2

1

3 ) 2

1

4 1 2

1

4 2

2

2

4 3

1 2

4 3

2

2

2 1

)

1 KEY TO MATRIX ENTRIES

C - IMPORTANCE OF TRANSACTIONS

1 = Purely convenience

2 = Strongly desirable

3 = No real alternatives

4 = Essential

B - RATE OF CHANGE

D - (IN)ADEQUACY OF SERVICES

0 = No improvements needeci

1 = Could be improved

2 = Marginal

3 = Serious deficiencies

4 = Out of control

- MAGNITUDE OF TRANSACTIONS

N = Declining

0 = Stable

2 = Growing

4 = Growing explosively

R = Flow of requi rements infti^ dominates

? = Unknown, X = Not studied, Blank = 0 4

Trivial

Mi nor Moderate

Important

Major
NBSIR 75-943

TRANSACTIONS MATRIX DESCRIPTION

OF THE

NATIONAL SYSTEM OF PHYSICAL MEASUREMENTS

Raymond C. Sangster

NBS Institute for Basic Standards

March 1976

EXECUTIVE SUMMARY

Direct measurements transactions matrices

have been developed to describe the U.S. national system of physical measurements.

Three primary axes have been used: A. Suppliers

of measurement information, goods, or services.

B. Users. C. Measurement Sectors (kinds of • measurement quantity) being described. These

three axes define three different kinds of

matrices: I. The matrix for a given measurement sector, showing the exchanges of measurement information, goods, and services between

suppliers and users in that sector. II. The

matrix for the inputs to a given user sector

from all of the different supplier sectors, for

all of the measurement sectors. III. The

matrix for the outputs of a given supplier sector, to all of the user sectors, for all of the

measurement sectors. A summary supplier-user

matrix has been generated by summing over all

of the physical measurement areas studied,

plus use of independent economic data.

Semi-quantitative estimates are entered in the intersection boxes in the matrices for the

following quantities: (a) Magnitude of transactions involved, (b) Rate of change of that

magnitude, (c) Relative importance or critical ity of transactions, independent of magnitude, (d) Adequacy of transactions. Basically, a five point (0-4) logarithmic scale has

been used; a change by one unit correlates

approximately to a change in magnitude, for instance, by a factor of three. Most estimates

of these code entries have been made on the

basis of intuitive, informed judgment. Approximately speaking, there is one chance out of

three that any given estimate is improper -- either too high or too low. Zeros have been

suppressed in these tables, so that a blank

box means an estimate of a negligible transactions magnitude.

The measurement sectors studied are these:

Time and frequency

Length and related dimensional measurements

Vibration and shock

Surface finish

Mass, volume and density

Force

Fluid flow

Pressure

Temperature

Humidity and moisture

Thermodynamic properties of fluids

5

Cryogenics

Electricity

Electromagnetics

Medical ultrasonics

Acousti cs Radiometry and photometry

Spectrophotometry

Far ultraviolet radiometry

Optics

Lasers

Physical properties of atoms and molecules

Surface properties

Ionizing radiation

The supplier and user sector lists have

been defined to be identical. As a result,

all of the intra-sector transactions are explicitly accounted for, in the diagonal

elements of the supplier-user matrices, and

all of the user needs information feed-back

transactions between the users and suppliers

of goods and services are entered. Standard

Industrial Classification (SIC) categories

have been used whenever possible. The

supplier-user categories employed are the

fol lowing:

Knowledge community

International metrological organizations

Documentary standardization organizations

Instrumentation industry

NBS

Other U.S. national standards authorities

State & local office of weights & measures

Standards & testing laboratories & services

Regulatory agencies

Department of Defense

Civilian federal government agencies

State and local government agencies

Industrial trade associations

Agriculture, forestry, fishing; mining

Construction

Food, tobacco, textiles, apparel, lumber,

furniture, paper, leather

Chemicals, petroleum, rubber, plastics,

stone, clay, glass

Primary & fabricated metal products

Machinery, except electrical

Electric and electronic equipment

Transportation equipment

Transportation and public utilities

Trade, retail & wholesale; insurance,

finance, real estate; other services;

printing & publishing

Health services

General public

NBSIR 75-948

ECONOMIC ANALYSIS OF THE NATIONAL MEASUREMENT SYSTEM

Barry W. Poulson

Department of Economics

University of Colorado

July 1976

EXECUTIVE SUMMARY

The first part of this study deals with the

concept of measurement for economic analysis,

the qualitative dimensions of measurement in

the economy, and the relationship between

measurement and economic change. Measurement goods and services yield benefits to users by extending the physical, human senses

in providing information about the properties

and characteristics of physical objects and

phenomena. Measurement information is ubiquitous in the economy; it is used as an input

at the interface between buyers and sellers.

The making of measurements is resource using,

the instruments, labor, and other resources needed to make measurements each have their

costs and these costs represent the total

cost of the national measurement system. The

National Bureau of Standards has begun to study the macro economic dimensions of the

national measurement system, and one approach

in this study is a measure of the cost of

labor and equipment used for making measurements. The cost of these resources used in making measurements was estimated at $36

billion or 6% of GNP in 1963. Each of the

78 major industries studied incurred substantial expenditures for measurement equipment and labor in 1963. Industries that

have experienced the most rapid rates of

growth and productivity advance also tend to be measurement intensive, i.e., measurement

expenditures are high relative to value

added by these industries. The Metric Study

by the National Bureau of Standards also

provided insight into the macro economic

dimensions of the transition to the metric

system. The cost of conversion to the metric system over the period 1970 to 1980 was estimated to equal 10% of the total cost of

measurement in the economy in those years.

The second part of the study examines the

measurement system from the standpoint of the

private sector, including the economic rationale for measurement by producers, consumers,

and in exchange between producers and con- sumers; and case studies of the costs and

benefits of measurement in the private sector. While it is impossible to analyze the

benefits of the total national measurement

system, it is possible to examine benefits

7

and costs of marginal changes in the measurement system. For example, it is estimated

that improvements in the accuracy of moisture

meters used in producing corn eould save farmers from $194 to $285 million per year.

Improved measurement can also yield significant benefits to consumers. X-rays and other

ionizing radiation are widely used for both

treatment and diagnostic purposes, yet only

65% of the hospitals surveyed proved to have

tumor dosage within an acceptable range of

accuracy, and 34% of dental x-ray machines

inspected were in violation of safety standards. Improved measurement in sales trans-

•actions not only improves efficiency, but

also results in more equitable transactions.

For example, an improvement of only 0.1% in

the accuracy of pipeline gas meters would re- duce the uncertainty of gas transferred equal

to $1,000 per day per meter station.

The third part of the study deals with the

role of government in the measurement system,

incorporating an economic rationale for mea- surement activities by the public sector, and case studies of costs and benefits of activities by the National Bureau of Standards ex- tracted from the micro studies. Information

provided by measurement is a public or collective good to the extent that the information provided by a single measurement can be

given to any number of people with no one suffering a loss of the information. The

production of measurement information is

sometimes characterized by increasing returns;

producers of measurement information often use specialized equipment and personnel who make

relatively few measurements. The marginal

cost of taking an additional measurement

likely is less than the average cost, and the

cost of disseminating the measurement information from one person to another is probably

trivially small compared to the cost of making the initial measurement. Finally, measure- ment is accompanied by external economies in such areas as consumer protection, health and

safety, international trade, and research and

development. Under the above conditions the

private market system may not allocate re- sources to the measurement system efficiently

and government intervention in the national

measurement system may increase the general

wel fare.
The role of the National Bureau of Standards in the national measurement system is

based on provisions in the Constitution and

on enabling legislation designed to implement those provisions. This study discusses

the costs and benefits of National Bureau

of Standards activities in maintaining basic

standards, in conducting measurement research

and development, and in providing calibration,

dissemination, and publication services. The

costs and benefits of selected National Bu- reau of Standards projects are quantified,

including large force calibration, time and

frequency service, coaxial connectors, standard reference materials for iron and steel,

standard reference materials for metals in

oil, semiconductor resistivity, and LPG

meter calibration. While none of these

studies satisfies the conditions of rigorous

cost benefit or cost effectiveness analysis

they do provide insight into the economic

role of the National Bureau of Standards in

the national measurement system.

8
NBSIR 75-949

STRUCTURE AND FUNCTIONS OF THE NATIONAL MEASUREMENT SYSTEM

Raymond C. Sangster

NBS Institute for Basic Standards

June 1976

EXECUTIVE SUMMARY

The National Measurement System consists

of all of the activities and mechanisms--

intellectual and operational, technical and

institutional--that provide physical measurement data to allow the creation of the objective, quantitati ve"i<nowledge required by our society. This report describes the

functional and structural aspects of the

System.

Measurement is necessary in conduct of

the life of the individual, pursuit of science,

operations of society, and employment of

technology. Measurements allow human beings

to describe, predict, communicate, decide,

control, and react in dealing with what is, was, or will be in the physical universe.

The process of measurement requires intellectual comprehension of the phenomenon, quantity, or property to be measured; definition

of a reference unit in terms of which the

measurement will be made; existence of a means of comparing the unknown to be measured

with the reference unit; establishment of a physical reference standard which embodies

the measurement unit; agreement within the

human community on all aspects of the mea- surement process; and mechanisms to enforce

honesty and clarity in measurements.

Our model of the National Measurement System involves five structural levels.

I. Conceptual Foundation of measurement

phenomena, quantities, units, and definitions.

II. Basic Technical Infrastructure to provide tools, techniques, and agreements

that allow the conceptual system to be re- duced to practice.

III. Realized Measurement Capabilities,

abilities to measure specific quantities to known accuracies under defined conditions.

IV. Dissemination and Enforcement Net- work, institutions that disseminate realized

measurement capabilities to users and enforce

their use.

V. End-use Measurements.

The basic phenomena and quantities to be

measured include space or distance, time, mass or amount of matter, electricity, tem- perature, amount of substance, and luminous

intensity. Many subsidiary units are derived from the basic units. The United States

uses both its customary "English" system of

units and the modernized metric system, SI.

9

The technical means required to make mea- surements include both physical hardware and

intellectual software. Software aspects include documentary specifications and standards, descriptions of measurement techniques,

educational materials, reference data, predictive methods, and the basic recorded knowledge of science. Hardware aspects include

transfer and working standards, reference

materials, and measurement instruments.

Documentary standards and specifications

include international treaties and conventions; Federal and state constitutions;

Federal, state and local laws and ordinances;

engineering standards; and procurement

speci f ications

.

Suitable instrumentation is the one indispensable element in any measurement process. Both physical apparatus and techniques by which it can produce the desired

results must be available.

When a given aspect of matter, material,

or fabricated product is sufficiently stable,

well defined, and of wide enough interest,

measurement data that characterize it can become useful as reference data. Existence

of reference data takes a substantial load

off the operational measurement system,

since it eliminates much repetitive measurement. Measurements of unknown systems are often performed by comparison with known

systems, using reference data. Such data

may also be used to calibrate measurement

equipment. Further, properties of materials

may be used to define the measurement process

itself, as in use of properties of water to define the temperature scale.

Reference materials complement and supplement reference data in the Measurement

System. Their function is very similar to that of reference standards, and for some phenomena, such as density, the reference

standards are reference materials.

In some measurement circumstances, the

volume of data needed may be so large, or

the experimental circumstances so inaccessible, that it is not physically or economically feasible to measure all of the desired data. Predictive methods--models of the

phenomena being measured--then become an essential element of the Measurement System.

The central core of the Measurement System consists of knowledge or science and of

the people who employ it. In some cases.
this central pillar by itself holds the

System together.

The institutional elements of the System

include the documentary specifications and

standardization institutions, the instrumentation industry, central measurements standards authorities, state and local offices of

weights and measures, standards and testing

laboratories and services, and technical regulatory agencies.

Documentary standardization institutions

operate at levels from the international to the individual company or local governmental

unit. The major relevant bodies are the

International Organization for Standardization, the International Electrotechnical

Commission, the American National Standards

Institute, the American Society for Testing

and Materials, the Department of Defense,

and the General Services Administration.

Over 2000 companies have products listed

in the current "Guide to Scientific Instruments" [267]. Economic dimensions of this

industry are described in an- Appendix to this report.

Legal responsibilities for enforcement of

justice in the use of weights and measures in our domestic commercial marketplaces lie with

the state and local offices of weights and measures; the National Conference of Weights

and Measures is the central coordinating unit.

Its paid staff and executive secretariat are provided by the NBS Office of Weights and

Measures

.

Standards and testing laboratories and

services function as "miniature NBS's" by

providing physical standardization services

to specific portions of the National Measurement System. The most highly developed institutional structures are in the military

services. The National Conference of Standards Laboratories is a central organization

here. The NBS Office of Measurement Services

provides its central secretariat.

Promulgation, enforcement, compliance, and

adjudication with respect to the regulatory

actions of technical regulatory agencies re- quire a substantial measurement base and com- prise a significant portion of the System,

making the regulatory agencies the newest re- cognizable institutional structural element

of the System.

The National Bureau of Standards is the

primary authoritative central measurement

standards institution in the United States.

Its calibration and related measurement ser- vices provide access to the national standards

of physical measurement; it operates the

National Standard Reference Data System and

provides Standard Reference Materials; it

provides coordination services to the System

through such Offices as those of Weights and

Measures, Measurement Services, and Radiation

Measurement, and through the Standards and

Applications Division, the Office of International Standards, and the Office of

International Relations; and it provides a variety of information services. Historically, NBS has served the Nation in three

primary roles, related to measurements,

standardization, and technological development. Today, its technological development

role is limited to a few specialized areas,

and its role in standardization is that of

facilitator to other interests. It is in

the field of measurements that its role is

unique in this country; if NBS did not

exist, it would have to be invented. The

NBS operating budget comes from direct appropriations by Congress, user reimbursements

for routine services, and funds transferred

from other operating agencies to cover the

costs of special technical services. A series of evaluation panels established by

the National Academy of Sciences supports

the Bureau management in optimizing the NBS

program.

The U.S. National Measurement System is

embedded in and part of an international

measurement system, for which the International, Bureau of Weights and Measures (BIPM)

is the central institution. Collective and

bilateral interactions among the various

national standards laboratories comprise the

balance of the institutional aspects of this

system.

The major trends of our National Measurement System can be described under the headings of increased complexity, increased integration, improved quality control, improved

information resources, automation, metrication and science. The development of the

information economy and the rising tide of

complexity, confusion, and "noise" in our society both imply increased pressures on the Measurement System to produce exactly

the measurement data needed, with exactly

the required precision, no more and no less.

Increased integration of the System is re- quired to improve its ability to provide

most economically and effectively this needed measurement data. Improved quality control, through such mechanisms as the NBS

Measurement Assurance Programs, goes hand in

hand with the previous two points. Automation is vastly expanding the technical

power of the System, by removing barriers

associated with limitations of the human

hand and mind. Passage of the Metric Conversion Act of 1975 recognizes a major trend in

the System, which will have a permanent impact on this country. The scientific developments of the past quarter century have

put us in a position to nearly realize the

dream of the founders of the metric system,

namely a universal system for physical mea- surements founded on natural law and a single

constant of nature.
NBS SP 445-1 THE NATIONAL MEASUREMENT SYSTEM FOR TIME AND FREQUENCY

Allan S. Risley

NBS Time and Frequency Division

May 1976

EXECUTIVE SUMMARY

The major purpose in studying the National

Measurement System for Time and Frequency was

to determine who uses time and frequency, how

they use them, and what their use means to society.

The system is viewed from three vantage

points:

1. The instrvmentation that provides

sources of time and frequency (T&F).

2. The suppliers and users of T&F.

3. The calibration hierarchies for T&F

sources

.

Most of the work of this study went into

determining the present status of the system.

Historical information was, however, helpful

in forecasts of the future and in putting

NBS T&F activities into perspective.

Instrumentation . The major types of instrumentation which have served as sources of

time and/or frequency over the last 75 years

are pendulums, tuning forks, quartz oscillators, and atomic oscillators. Quartz and

atomic oscillators are the sources of primary

importance today.

The characteristics of precision quartz

oscillators, superconducting cavity oscillators, and the major atomic oscillators are

given, and some of their areas of application

are described. For example, atomic oscillators are shown to be an increasingly important part of the telephone industry and basic

science. The National Bureau of Standards

has been a central element in the research

and development of atomic T&F standards

throughout the some 25-year history of these

standards. The Bureau has also made some

basic contributions to the development of

precision quartz oscillators.

Suppliers and Users . A compact description

of fourteen basic supplier-user categories is given in matrix form. The relationship between a given supplier and user is specified

by two descriptors. One descriptor gives the

volime of use of a specified time or frequency output. The other gives the importance (to an organization's internal operations) of that output.

The majority of the effort devoted to this

study of the National Measurement System for

Time and Frequency went into extensive

studies of eight major areas. They are:

- Standards Laboratories

- Users of NBS Radio Broadcasts

- Telephone Industry and Specialized

Carriers

- Military

- Position Location

- Aviation Industry

- Electric Power Industry

- Shipping and Boating Industries

Information gathered in these studies was

vital in completing major portions of the

T&F flow matrix. The communication and position location industries emerge as two of the

most important and sophisticated users of

T&F. The matrix indicates the great importance of the NBS standard T&F broadcasts. A current study is increasing our understanding

of the users of stations WWV and WWVH. The

study confirms that the applications of

communications, navigation, and standards

laboratories are very important. The three

most heavily used aspects of our broadcast

services are voice announcements of time-ofday, one-second "ticks", and standard frequencies.

Calibration Hierarchies . The various

sources of time and frequency must be compatible with one another to within some specified tolerance. The stringency of this re- quirement depends on the sources involved and

the uses to which they are to be put. The

necessary compatibility is often achieved by means of a calibration hierarchy.

There is no legal, technical, or economic

force to create a unified calibration hierarchy, and none exists. This is one reason

why it is difficult to comprehend the

National Measurement System for Time and Fre- quency. Multiple hierarchies do exist, how- ever, and they are basic to the system. Some

of these hierarchies have the force of law

and apply across organizational boundaries.

Others are voluntary or are only binding

within one organization. Those not having

the force of law usually have the greatest

requirements for quality of T&F. To understand why these several hierarchies exist, it

is essential to consider cost and ease-of-use

as well as quality.

11
Four major calibration hierarchies are

those of the standards laboratories (industrial, governmental, etc.), telephone timeof-day, the military, and the telephone

industry. The National Bureau of Standards

has been a part of these four hierarchies.

It is presently a fundamental part of the

standards laboratory hierarchy and telephone

time-of-day. It is also an important part

of the military T&F calibration system.

The National Bureau of Standards' importance

to the telephone industry is much less than

it was in the past (since the telephone

industry is now basing its synchronization

on atomic oscillators), but is potentially

still important.

The Future . The system appears to be

changing in three major ways:

1. ) By 1980-85 there will probably be a widespread, low-cost network of

clocks that are synchronized in the

range of 1 to 10 ys. Today, widespread synchronization, at a cost of

a few hundred dollars per site, can only be done to about 1 ms.

2. ) By 1980-85 the market for frequency

equal izati9^ in the range 1 x 10" to 1 X 10" will probably be quite

important. The cost per site will

need to be less than about $2000 (in

1975 dollars), and the equipment must

be easy to use.

3. ) The use of quartz watches and clocks,

with digital readouts and the capability of being set to the precise

second, will probably be extensive.

This may necessitate a widespread

calibration network for time-of-day

that is accurate to about 0.1 seconds.

The Time and Frequency Division of NBS

currently has two programs - T&F dissemination via satellite, and frequency calibration

via TV - that address the first two areas

of probable change. A third program directed

to these frequency equalization requirements,

a low-cost, medium-accuracy oscillator, will

likely begin soon.

The third area of probable change, if it occurs, will be more of an economic than a technical problem. As such, it would not likely increase the demand for NBS resources with regard to time-of-day.

Conclusions . This study of the National

Measurement System for Time and Frequency

clearly demonstrates that NBS has an important and unique role in the system. The

question is not whether there are desirable

alternative sources for the services presently rendered, or whether these services are in fact needed. It is instead whether NBS can perform its function more economically and

effectively. Experimental broadcasts of

standard T&F via satellite and other developments indicate that it can do both.

The NBS T&F services hc(ve been, and are,

and should be, in the nature of what econo- mists call a "collective good". This is a "good" (product) which is clearly of social

value but one for which a fair market price

is difficult to determine. It is interesting

to note however, that there is now d, minimum

of one million dollars worth of special

purpose receiving equipment in the field.

This equipment was specifically designed to receive the broadcasts of WWV and WWVH or WWVB. Also, if $0.05 per call were received

for the J^BS telephone time-of-day service

this would generate a revenue of $50,000 per

year.

One of the most general things that

emerges from the entire study is that time - and its ever-present companion, frequency - are the great coordinators, the great organizers. Almost any activity today that

requires precision control and organization

rests on time and frequency technology.

(A diligent effort has been made to make

this report comprehensive and accurate as of

March, 1975. Since that time no important

changes or additions have been made. There

have, however, been a few significant changes

in the National Measurement System for Time

and Frequency. The interested reader may

wish to contact the author for his opinions

on these changes .

)

12
NBSIR 75-926 THE NATIONAL MEASUREMENT SYSTEM FOR LENGTH AND RELATED

DIMENSIONAL MEASUREMENTS: PART 1

J. W. Lazar and R. L. Bach

NBS Mechanics Division

March 1975

EXECUTIVE SUMMARY

The determination of length and related

dimensional measurements constitute the

largest group of measurements made in science, manufacturing, and technology. It has

been estimated that 80% of all measurements

made in industry are of length and displacement. Figures developed from our recent

study of the National Measurement System

shows that an average of S9.4 billion is ex- pended annually by the manufacturing sector

alone to perform dimensional measurements in our economy.

Length and related dimensional measurements have impact upon many areas of the

economy. The largest area is in manufacturing and within manufacturing the firstorder impact areas are air frames and aircraft equipment, ball and roller bearings,

car accessories, domestic appliances, electronic equipment, gears, general engineering,

geodetic investigations, integrated circuit

industry, photogrammetry , research and development, screwthread industry, scientific

instruments, and watches. In many of these

areas dimensional measurements are made to satisfy functionality requirements and little

else. For example, the parts of an automobile engine would not fit properly if they were measured with different micrometers

which were not accurately calibrated.

In the course of our National Measurement

System study in Length and Related Dimensional Measurements, we have established

over one hundred and fifty contacts with

individuals within governmental agencies;

industry, professional societies and organizations; scientific and trade journals; and

universities and colleges around the nation.

Many of these people contacted were sur- prised that we were willing to listen to their problems in dimensional measurements.

In almost all cases, the organizations con- tacted expressed a keen desire to continue

the dialogue established between the Bureau

and their oersonnel

.

The primary industrial contact was within

Standard Industrial Classification 3548, Ma- chine Tool Accessories and Measuring Devices.

This industry was expanded into further pro- uct codes such as 35452, Precision Measuring

Tools; 3545211, Comparators; 354221, Gage

Blocks; etc. In many cases the contacts expressed no pressing need for any greater

accuracy in standards for dimensional mea- surements. For example, the accuracy inherent

in various dimensional artifacts (gage blocks,

etc.) and instrumentation (laser interferometers, etc.) far outpaces the ability of many

to transfer displacements obtained from these

devices to other objects. (This is verified

by viewing the results of some recent surveys

contained in our report illustrating inconsistencies of 0.00177mm to 0.00254mm-70 to 100 microinches-in the measurement of internal diameters of finely finished ring gages.

The primary users of the National Bureau of

Standards' most accurate dimensional measurements are the Department of Defense Primary

Standard Laboratories, the various gage and

measurement instrument manufacturers, and the

private standards laboratories including those

who only service the parent organization.

Another major user category of NBS ser- vices is the machine tool industry. In the

recent U.S. Industrial Ov.tlook 1973, the machine tool industry ranked first in percentage

increase in value of shipments from 1972 to 1973 (27 percent increase from $0,825 billion

to $1,050 billion). An increasing percentage

of manufacturing is being done under numerical control (NC). NC machine tool shipments

are growing three times as fast as conventional machines and it is estimated that 15-

20% of U.S. metalworking machine tool shipments are currently NC. There are pressing

needs to develoo standards and algorithms to characterize the accuracy of these machines.

The reason for accurate calibration of NC

machines is that the accuracy of parts produced is 100% dependent on the inherent positioning accuracy and geometry of the machine

tool . The areas of surveying and geodetic investigations are frequent users of NBS calibration facilities (tapes). In recent years

calibrations have been steadily declining and

the 1974 NBS calibrations in this area were

only approximately 20% of the same services

in 1971. We have found that with the recent

advent of relatively inexpensive electronic

distance measuring devices, many companies

and individuals are now able to afford these

devices

.

We had initiated steps to interact with

the machine tool industry to a greater ex- tent even to the point of obtaining compli13
mentary exhibit space in the International

Machine Tool Show (IMTS) in September 1974 in

Chicago. The specific purpose of our exhibit

was to listen to and view first-hand some of

the measurement problems within this important area. Four hundred and sixty-one people

requested 1300 copies of the various dimensional technology and optics and micrometrology reports. The majority of these reports

are the "how we do it" type.

One fact has been repeatedly borne out from all contacts--the need for more awareness of the work being done at NBS and the

need for more publications at multi levels

discussing how to make accurate and precise

measurements.

The results of the recent NCSL audit package measurements show the need for dimensional artifacts to verify the accuracy and

precision of industry's gages and measurement system other than the standard set of

gage blocks, angle blocks, plug and ring

gages, spheres, etc. NBS should develop

these standards and make them available to the various laboratories for their use to determine the accuracy and precision of their

measurement system. In addition NBS should

develop, in conjunction with industry, a three dimensional artifact to be used to determine the accuracy of their three dimensional measuring machines as well as their

complex NC machining centers.

14
NBSIR 75-926 THE NATIONAL SYSTEM FOR LENGTH AND RELATED

DIMENSIONAL MEASUREMENTS, PART 2: MECHANICAL VIBRATION AND SHOCK

John D. NBS Mechani'

August

EXECUTIVE SUMMARY

The technical areas of mechanical vibration and shock are examined within the framework of this National Measurement System

Study. Manufacturers and users of vibration

test equipment were contacted to ensure that

an accurate as possible assessment was being

made. Of special interest are areas where

vibration measurements are assuming more importance to the nation. This investigation

sampled the manufacturers and users of vibration equipment to determine the true nature

of the vibration and shock infrastructure.

The scope of this study includes the following mechanical motion parameters: The principal dynamic vibration parameters are displacement, velocity, and acceleration. Para- meters of secondary interest to this study

are dynamic force, mechanical impedance,

damping, and transmissibility (related to vibration isolation). These secondary parameters are not all discussed in detail, how- ever, they are discussed as they relate to measurements for areas of machine and tire

balancing, vibration isolation, and vibration damping.

Vibration and shock measurements are vital

to several large and important sectors of

the U. S. economy. Testing of military ord- nance and other hardware have critical re- quirements for shock and vibration measurements. The aerospace industry utilizes vibration as a key element in the development

and testing of aircraft, rockets and satellites. Rotating and reciprocating machinery

require (in some instances crucial) balancing

for proper operation. Auto makers must, by

Federal regulations, make safety related

crash tests. And, household appliances are being subjected to vibration tests to improve

their reliability and durability.

The suppliers of vibration and shock measuring instruments, and generating equipment

(i.e., vibration generators and shock ma- chines) were analyzed and their number and

economic size determined. About 18 of 40 plus

companies dominate the market. They have

an estimated annual sales of about $200

million. The suppliers of vibration isolators and damping materials number about 45

of which 8 are considered dominant. Their

annual sales are estimated at $110 million.

There are about 32 manufacturers of balancing machines of which 9 are dominant. They

Ramboz

s Division

1975

have an estimated sales of $95 million. In an overall composite of the entire number of

suppliers included in this study, there are about 42 predominant companies out of a total

of 132. The total annual sales are estimated

as $405 million.

The measurement infrastructure for vibration and shock is examined by accuracy needs,

types of applications, and amplitude and

frequency ranges. Critical applications such

as ordnance testing or aircraft development

and testing require traceable vibration and

shock measurements. These amount to about

one-half of all the vibration measurements

made. Such measurements often specify un- certainties in the range of +5 to +20 percent

of vibration amplitude and +1 to + 5 degrees

of phase. The instrumentation used to monitor these types of tests are usually calibrated by comparing them to standards that

the companies or agencies maintain. Ultimately, the standards are calibrated by NBS

as reference standards. The measurement

infrastructure also includes a large number

of less critical vibration measurements, for

example, in dynamic balancing rotating and

reciprocating machinery. Measurement un- certainty may range from +10 to +200 percent

of the vibration amplitude. In many of these

applications, so long as the vibration level

is safely below a specified value, accurate

measurement need not be supported by a com- plex traceable chain to NBS. Some measurements within the infrastructure do not even require accuracy whatsoever; only sufficient

sensitivity to be able to detect vibration

and to be able to measure relative changes

in the vibration level. A common example is

dynamic wheel and tire balancers. Where

traceable vibration standards are needed, the

NBS provides a calibration service on a reimbursable basis.

With the exception of shock measurement

standards, the vibration standards and procedures are generally adequate for the

majority of needs. A comparison shock calibration service is available at NBS with

additional refinements required. There is a serious need for absolute calibration methods

for shock which are currently being developed.

As a result of this study, gaps in the meas- urement methodology have been assessed in areas of vibration isolation and in damping.

Efforts are being directed towards both of

these areas.

NBSIR 75-927

THE NATIONAL MEASUREMENT SYSTEM FOR SURFACE FINISH

Russell D. Young

NBS Optical Physics Division

August 1975

EXECUTIVE SUMMARY

Surface finish measurements involve the

outside surfaces of products, the part which

is most evident to the user and which is frequently responsible for the quality of its

performance. The average consumer can visually detect less than one millionth of an inch

of surface roughness in a highly finished

chrome plated surface. The reliability of

clock motors, the performance of switches,

the effectiveness of razor blades, the safety

of a wheel bearing, all of these depend on careful measurements of manufactured surfaces.

The National Measurement System for surface finish consists of the standards, the

measurement techniques and procedures, the

personnel, and the equipment through which

surface finish measurements are conducted in

the United States, The purpose of this study

was to determine as quantitatively as possible

the structure, vitality, integrity and future

requirements of this measurement system. The

study was initiated by a literature search,

followed by visits to instrument manufacturers,

industrial laboratories and academic institutions.

Each of the hundreds of metalworking industries has a special surface finish requirement.

The highly polished pipes and tanks of the

dairy, food and hospital supply industries

permit rapid sanitation inspection. Quality

of magazine illustrations depends upon the

surface finish of gravure plates and cylinders.

Automotive safety and reliability is related

to the surface finish of hundreds of bearing,

seals, brake drums, valves, cylinders, etc. The lifetime of surgical implants is directly

related to their surface finish. Military

applications abound. The list is endless.

Yet, each application requires different sur- face micro-features. The most important con- clusion of this study was that NBS should

develop measuring procedures and methods for

analyzing surface profiles so that each metal

working industry can properly inspect its

surfaces according to its needs.

The second most important measurement need

is for instrumentation capable of measuring

new, high technology surfaces such as integrated circuits, computer discs and drums, surgical implants and precision bearings. New

molecular electronic devices require surfaces

which are smooth on the atomic scale. A third

important need is for on-line surface finish

measurement in manufacturing processes.

NBS calibrates precision reference specimens of surface roughness (carefully m,anufactured rough surfaces) according to the voluntary American National Standard B46.1. These

specimens provide calibration users with a readily available physical standard to check

their instruments. The integrity of the mea- surement system is maintained by national and

international intercomparisons and by direct

calibration of users' standards. There are

no regulatory agencies in surface finish.

NBS also calibrates thin film steps for the

microcircuit industry. Since both thin film

steps and surface finish measurements are basically length measurements, NBS bases

these calibrations on the defined unit of

length through interferometry

.

The information gathered in this study

has already provided a solid basis for management decisions within NBS with regard to the

distribution of the very limited resources in

the surface program (2 1/3 man years; $84K

of NBS funds). For example, first priority

has been given to a new calibration facility

which includes computer analysis of surface

profiles. Second priority is assigned to the development of new, high resolution instrumentation. Work with standards committees

also has a high priority.

The study revealed a broadly based need

for research leading to an understanding of

the relationship between the surface finish

and the function of a part. Such a study

cannot be underwritten by instrument manufacturers since the 25,000 instruments now in use are very long lived. Yearly sales of the

largest U.S. instrument manufacturer amount

to only $1 million per year. The metal

working industry spends $54 million yearly

in making surface finish measurements on products whose market value exceeds $40

billion. Yet this effort is thinly spread over hundreds of industries, so that little

reported research is done. These circumstances have resulted in stagnation in U.S. surface programs relative to governmentsupported foreign research. NBS is now

able to provide measurements and instrumentation to those who wish to pursue such

programs in the U.S. Several small cooperative efforts with industry and a university are now underway.

17

NBSIR 75-928

THE NATIONAL MASS, VOLUME, AND DENSITY MEASUREMENT SYSTEM

P. E. Pontius, J. A. Simpson, and J. R. Whetstone

NBS Mechanics Division

June 1975

EXECUTIVE SUMMARY

Mass, defined as the quantity of matter

in a body, is measured by determination of

the magnitude of its attraction by the earth

via the weighing operation. The mass unit,

the kiloaram, is unique amonq the Fundamental Units of the International System of

units in that it is a man-made object-International Standard Prototy-pe K-kept at the

Bvjreau Interruztionat des Voids et Mesures

(Sevres). The U.S. unit is defined by the

replicas of K Prototyve Kiloarams No. 4 and

No. 20. Volwne is a quantity derived from the

meter whose unit is the cubic meter. It is

inevitably coupled with mass since the most

convenient method of measuring volume is to determine the mass of the water the volume

contains. The intent of the founders of the

Metric System was that one cubic deciliter

of water have a mass of one kilogram, although its reali-zation has proven to be imperfect.

Density is a quantity obtained by dividing the mass of an object by its volume and

it completes this closely related triad.

Extending from this triad are the force

and pressure measurement systems which are themselves subjects of the National Bureau

of Standards National Measvcrement System

studies.

The chain of national measurement activity extending from the narrow peak of the

10 man-year effort at NBS is staggering.

Mass calibrations, a $25,000 a year billed

effort, supports a clientele who produce

80 billion dollars of goods and services.

A much smaller effort on the part of the Mass and Volume Section supports the State's

Weights and Measures Enforcement activity

by way of the coordinating efforts of the

Office of Weights and Measures. This effort

chains to the corner grocery store where

about 84 million weighings a day are performed. These weighings in turn necessitate

a 145.1 million dollar a year industry to manufacture the weighing devices needed.

The impact of volume measurements on the

economy is equally impressive. Volume meas- urements are made at all levels of the

economy from research laboratories to milk

processing plants. This study is concerned

with glass and metal containers which form

the basis of all volumetric measurements

including flowmeters, etc. The 1972 sales

for scientific/laboratory glassware and industrial/technical glassware totaled over $154 million of which a large part were devices for volumetric measurement such as burets, pi pets, etc. With the current interest in the petroleum industry, it is interesting to note from figures given at the dth World Petrolevm Congress, that the petroleum industry

has a measurement investment in volume mea- surement facilities of $1,800,000,000 located at 650,000 sites, manned by 50,000 fulltime personnel and that each barrel is mea- sured on the average of 12 times between

well head and consumer. A 5% error represents an accounting discrepancy of $65.00

per thousand barrels.

Density, the least appreciated member of

the triad, more than holds its own. Density measurements are used in the pe- troleum, sugar, milk-processing industries

and by the Internal Revenue Service, hospitals and various research laboratories.

Density determinations are used for materials identification and sorting, assaying,

and manufacturing process control.

One of the most widespread devices for

measuring density is the hydrometer. The

value of shipments of hydrometers rose from

$4,626 million in 1971 to over $8,102 million in 1972. NBS services the national

measurement system for density through calibrations of manufacturer's and many large

user's master hydrometers. Six million dollars are expended annually by various users (manufacturers of beverages, industrial

chemicals, grain products, sugar, and electronic components) to perform density mea- surements, predominately using hydrometers.

This figure fails to illustrate the full impact of density measurements. For example,

in the beverage industry, approximately

$2.5 million is expended annually for density measurements in an industry having a total value of shipments of over $15.4 billion in 1973. A properly calibrated $15 hydrometer can often save a company thousands

of dollars in federal fines.

19
Despite the enormous leverage of the Mass

Measurement system, it appears to be in almost complete control and operating to the

satisfaction of all concerned. The happy

technical situation arises from the facts:

(1) that mass standards are intrinsically

stable so that the unit once injected into a subsystem remains consistent; (2) the instruments used are reliable; and (3) the

traditional Weights and Measures activities

stabilize the system since the available

measurement precision exceeds the needs of

trade and commerce considerably. The result

is a mature measurement system which has

been stable in the recent past and which can

be confidently predicted to remain so in the

foreseeable future. The origination and development of Measurement Assurance Programs,

which are programs designed to allow NBS or any other interested party to test the effectiveness of measurement subsystems relative to their intended use, provide a running audit of the system to insure that this

stability is not lost.

This study revealed only minor flaws--the

correction of which will form the basis of

the future program at NBS.

In mass the most immediate and closest to home flaw lies in the first transfer from

the prototype kilogram. The definition of mass equality calls for balance in a vacuum environment--the density of the objects

plays no role. In practice, weighings are performed in air where a density dependent

air buoyancy correction must be applied.

This buoyancy correction between the platinum prototype kilogram and the weights of

every day use amounts to about 80mg in a kilogram. Recent studies lead us to believe

the correction used by all national laboratories may be in error by the order of 1%. This error, if confirmed, means that the mass scale of commerce is offset from the

defined scale by as much as Img at the kilogram level. The offset is too small to affect the consistency of the U.S. mass scale

compared to the rest of the world, but it is

of importance for fundamental physical con- stants and must be resolved.

Further down the dissemination chain,

there are problems of a political nature

generated by the United States' recent joining of the International Organization for

Legal Metrology. This is a treaty organization and the U.S. is "morally obligated" to adopt its standards which conflict in some instances with U.S. practice. The National

Conference of Weights and Measures , the

principal mechanism for NBS influence on States' Weights and Measures activities has

expressed serious misgivings over the U.S. position and has raised questions which must

be resolved.

20

With respect to volume, our recent study

found the need existed for a good volume

standard for high pressure, large volume gas meters. Companies are currently using an awkward transfer process from a cubic foot

standard calibrated at NBS to a larger cubic

foot bell prover to specially constructed

rotary meters. The main impact would be on

the metering industry.

In the clinical laboratory user area, we found a desire by various individuals to participate in the development of uniform

standards for the calibration of certain

volumetric dispensing devices. The standards for measuring the delivery of a pipet

are cumbersome and not applicable to check

or calibrate many of the relatively new automatic diluters or dispensers which have

been marketed in recent years for clinical

laboratory use. One particular laboratory

which is heavily automated estimates that 1% to 2% of their tests are repeated "due to error created by inaccuracy in diluting or dispensing of samples of reagents". Clinical laboratories are one of the most rapidly

growing service industries having increased

sales from a level of $1.5 billion in 1965

to an expected $7 billion in 1975. Reduction of the number of repeated tests represents a cost savings to hospitals and to patients

.

Density measurement appears to be in control except for research in the areas of

fundamental constants and oceanography.

Commercial and industrial needs for accurate

density determinations are being satisfied

by commercially available instruments. Den- sity measurement precision has been limited

by the uncertainty in the density of water

to about 10 ppm. Recent work at NBS on solid artifact density standards has reduced

density measurement uncertainty associated

with reference standards to 1 ppm. Dissemination of this accuracy is in progress.

A need was identified in the beverage

industry for in-line density measurements

for process flow lines. In-line density

measurements are expected to increase manu- facturing efficiency. A recently developed

instrument, now commercially available, sat- isfies this need and is being used by portions of the industry.

The above listed flaws, notwithstanding

the NBS responsibilities in the area of mass, volume, and density, are judged to be

satisfactory and the level of effort now deployed is deemed to be correct in magnitude. The course of NBS activities for the

future lies in the correction of these flaws

and in the continued maintenance of the

current system.
NBSIR 75-929

THE NAlIONAL FORCE MEASUREMENT SYSTEM

Donald E. Marlowe

NBS Mechanics Division

June 1975

EXECUTIVE SUMMARY

This study outlines the detailed structure

of the National Measurement System as it

pertains to force, and assesses the economic,

social, and technological impacts of force

measurements in the United States.

Force, as a unit of measurement defined by

Newton's Second Law of Motion, is derived

from the basic units of mass, length, and

time. The most precise standards of force

are realized in deadweight calibration

machines such as those maintained by the

National Bureau of Standards, a few government laboratories, one commercial calibration

laboratory and a few industrial metrology

organizations. The deadweight facilities at

NBS are widely accepted as the national

standards of force.

In practice, deadweight machines are used

to provide a few precisely known forces for

the calibration of high quality force transducers such as load cells and proving rings.

These secondary standards are used to calibrate the multiplicity of devices for field

measurements. Accuracy requirements in the

measurement system range from the 0.002

percent accuracy of primary standards to about 10 percent for rough measurements such

as crane overload indicators.

Force measurements are often contractual

in nature. This is true whether the measurement is a strength of materials measurement

made in a testing machine or a weight mea- surement made at the local supermarket or in

a railroad freight yard. As a result, the

social and economic impacts of force measurements are very diffuse, even to include the

entire goods fraction of the economy. While

the greatest number of force measurements

are made in the metals and textiles industries, this diffusion tends to make force

measurements almost invisible. So many

measurements are made that each one costs

very little. For example, the impact of a single, well defined measurement is cited.

Federal regulations require that every eyeglass lens be proof tested before being

used. The lens manufacturers pass on to the consumer the SI. 00 per lens cost of the test. When you realize that about 100 million

Americans purchase about 200 million pairs

of glasses and sunglasses each year, the

direct consumer cost of that one measurement

is quite large. The contractual nature of

force measurements is often the "raison d' etre" of force measurement standards. Such

a standard, almost always a voluntary agreement upon the method of test to be used,

gives confidence to the buyer and seller

that an equitable business agreement has

been reached. This confidence is a non-measureabl e , economic, social -technological, impact of force measurements. If the

standards of force measurement did not exist,

the cost of doing business would increase to cover the cumulative uncertainties resulting

from inaccurate measurements.

The history of NBS and of force measurement in this country are closely linked,

beginning in the 1830's with the distribution of mass standards by the Office of

Weights and Measures, and continuing today,

with the development of proving rings-,

deadweight machines, and load cells and

test methods. In addition NBS has participated in the formulation of many of the

measurement test methods now in use. The

role of NBS at the primary standards level

in the measurement system is to provide

adequacy, stabil ity and consistency to the

system. No other organization is so uniquely placed to provide that function.

The best assessment of the National Force

Measurement System is that, while some aspects of it are stable and adequately

maintained, other needed parts of the system

scarcely exist. The historical areas of

effort in static force measurement, over the

range from 0.5 newtons (0.1 lbf)to 5 x 10^

newtons (1 x 10'' Ibf), are fully adequate

with the level of accuracy now provided and

will remain so for the foreseeable future.

They require only continued routine support

and maintenance. In the areas of dynamic

force, very small static forces, information

transfer and metrication, however, the mea- surement system shows serious weaknesses.

The measurement system for dynamic force

does not exist. The standards and test

methods that are needed to assure the

accuracy of dynamic measurements and the

reliability, efficiency and safety of load

carrying systems under dynamic conditions

such as impact and fatigue are not available.

A similar condition exists for the measurement of very„ small forces down to lO"' newtons (10"° Ibf). Measurements in this

range are needed in such areas as biomedical

research and ultrasonic, nondestructive

testing of manufactured parts.

21
The information transfer sector of the

system is quite cumbersome. This is a result of the diversity of groups performing

force measurements. In conjunction with the

adoption of a new method for the calibration

of force measurement devices, the system is now beginning to establish the lines of

information return from the end user to the source of primary calibration. NBS is actively promoting this exchange through

round robin calibration of devices and by

measurement workshops.

The anticipated metrication of force mea- surements has become an area of increasing

concern. In the field of force measurements,

the foreseeable- problems of education of

professionals and large, long-lived capital

equipment, have been compounded by the con- fusion about the unit of force which will

evolve in common usage. The SI unit of

force is the newton. However, European

common usage is the kilogram-force. This

usage has evolved in much the same way as the pound-force unit did in the U.S. This

confusion will delay the acceptance of the

SI unit and, as a result, force may be one

of the last SI units in common usage.

This study has served to verify many of

the current concepts of the condition of the

force measurement system. Several strengths

and weaknesses have been discovered and

studied. NBS, through its standards and

calibration activities will continue to have

a stabilizing and unifying effect on the

system. NBS should increase its efforts in areas of the system where weaknesses have

been found.

22
NBSIR 75-930 THE NATIONAL MEASUREMENT SYSTEM FOR FLUID FLOW

William C. Haight (coordinator), P. S. Klebanoff, Fillmer W. Ruegg, Gershon Kulin

NBS Mechanics Division

August 1975

EXECUTIVE SUMMARY

Fluid flow is a diverse field concerned

with the motion of a wide variety of fluids

encountered both in daily life and in scientific applications. It encompasses movement

of weather systems by atmospheric winds,

travel and dispersion of air pollutants,

flow around aircraft and spacecraft bodies,

oil and gas pipeline flow, irrigation and

waste water flow, and many others. The types

of fluid motions encountered in descriptions

of these phenomena include closed-conduit,

open channel, supersonic, subsonic, steady,

unsteady, laminar, and turbulent flow.

Measurements of the properties of these flows

are instrumental in the functioning of the

nation's industries and the advancement of

scientific technology, and impact the lives

of every consumer.

This report presents the concept of the

National Fluid Flow Measurement System as it

exists today and the activities and mechanisms it employs to generate and implement

measurement data. The system structure is

presented, and data and information gathered

on the interrelationships between the identifiable parts are reported. To further the

study, more than 200 contacts were made with

trade associations, government agencies,

private companies and universities.

The basic structural element of this

measurement system is the combination of the

fundamental units of mass, length, and time

to describe fluid response to external forces.

Such responses are generally velocity (m/s), mass flow rate (kg/s), or volume flow rate

(m^/s), but can include specialized quantities like Mach number and frequency of flow

fluctuations. Also affecting this response

are the inherent fluid properties, such as viscosity, density, thermal and electrical

conductivity, and bulk modulus of elasticity.

Documentary standards for fluid flow meas- urement represent international, national,

and commercial viewpoints, and are used voluntarily by all parties. International organizations such as ISO and lEC are active in fluid flow preparing measurement standards,

meter performance standards, and recommended

practices for making measurements and analyzing errors. Nationally, ANSI, ASTM, ASME,

API, and AGA prepare similar standards for

flow measurements commonly encountered in their application areas.

23

Measurements are made with a variety of

tools, some of which have been in use for a great many years, and others which are innovatively new. These instruments operate on a variety of principles including differential

pressure, force, convective cooling, sound

transmission, electromagnetic effects, vortex

shedding, and more recently light scattering.

In particular, vane and cup anemometers, water

current meters, and orifice flowmeters are among the most commonly used meters in meteorology, stream flow measurements, and pipeline

flow measurements respectively. A rapidly

growing area of new instrumentation includes

sonic anemometers, laser velocimeters , and

electromagnetic meters, the latter being used

in conducting fluids such as liquid metals,

wastewater and water under certain conditions.

Current capabilities, facilities and ranges

of services of numerous calibration and standards laboratories engaged in gas and liquid

flow measurement are identified. These include:

(1 ) Air flow

•80,000 scfm, 2800 psig at the Colorado

Engineering Experiment Station

•3,000 scfm, 125 psig at NBS

•2 to 150 mph at NBS

(2) Water flow

•40,000 gpm, 21 psig at Alden Research

Laboratory

•10,000 gpm, 75 psig at NBS

(3) Liquid hydrocarbon flow

•10,000 gpm, 40 psig at Brooks Instrument Division

•2,000 gpm, 50 psig at NBS

Additionally, over 60 instrument manufacturers

have been identified that are traceable to NBS

through calibrations submitted over the last seven years.

The study indicates a trend of U. S. domestic business in which total sales dollars have

increased for fluid flow measurement equipment

from $67.2 million to $123.3 million in the

period 1963 to 1973. The annual volume

continues to grow with mounting demands for

accuracy and sophistication of equipment. In testimony before the Congress, the manufacturers of scientific instruments testified

that about 25 percent of the annual value of

flow meters and instrumentation sold by the

industry is sold abroad. They believe that

these export cales exceed imports by more than

four to one, and they are the leverage for

export sales of instrumentation and control

systems valued at twice to three times the

flow measurement products.
state-of-the-art changes and technological

advancements in fluid flow include both

improvements in traditional instrument designs

and numerous new designs that are finding

increased application. Inflated fluid resource values and increased operating costs

in fluid transportation are forcing a general

rise in the cost to flow a unit of fluid.

Subsequently, greater investments are being

made in increased measurement reliability and

accuracy and in the managing and controlling

of fluid flow. Primary metering devices are becoming increasingly sophisticated. In general, the applications which impose the

most urgent requirements on flow measurements

are those which stem from the imposition of

new Federal regulations in fields that include

environmental air and water quality control,

coal mine health and safety, occupational

safety and health, and clean room and work

station requirements. Implementation of these

regulations will increase the requirements for

consistent and reliable measurements of many

flow quantities that cannot be measured

adequately today.

Specific fluid flow measurement needs are identified that include: providing new flow

standards, preparing reconmended practices,

and evaluating and developing instrumentation

for the measurement of low velocities and

unsteady speeds of air; reducing the uncer- tainties in values of discharge coefficients

for orifice meters; and providing new flow

standards, preparing recommended practices

for in-place applications, and evaluating and

developing instrumentation for the measurement

of velocities and flow rates of supply water

and waste water. A general trend has been

discerned underlying these needs in which

opportunities to implement measurement

assurance and the transfer-of-measurement

capability are becoming increasingly

important.

NBS functions as an integral element of the

fluid flow measurement system, conducting

fluid mechanics research and development, con- tributing to flow standards, and generating

engineering data on a variety of flows. Calibrations are offered for instruments to measure

velocity and mass flow rate in air, water, and

liquid hydrocarbons. NBS services impact

government agencies concerned with health,

safety, power, fuel resources, water resources,

weather monitoring, pollution control, and

military and space programs as well as major

segments of private industry such as the oil

and gas industry, power utilities, heating and

ventilating, and transportation. These user classes share a common concern for adequacy,

accuracy and reliability of the various

aspects of flow measurement.

Fluid flow measurement technology today

represents a constantly changing field, thus

supplying the impetus for a number of improvements within the National Fluid Flow Measurement System. In particular, a need for a national fluid flow reference system was emphasized at the 1974 NBS Flow Measurement

Conference. This need is underscored by discrepancies in flow calibration results, duplication of measurement efforts, the lack of a technical "third party" to arbitrate discrepancies in measurement, and the lack of

facility certification.

New measurement capability is also needed

in both the very small and very large rates of flow. For example, the automotive industry is targeting for fuel flow calibrations

at approximately .08 g/s with + 0.2 percent

accuracy. Also, very low velocity measurements are required in air and water flows in order to meet regulatory requirements being

established for health, safety, and environmental quality. The nuclear power industry

requires measurement of cooling water flows

on the order of 60,000 - 120,000 1/s per

minute, depending on plant power output. Such

Such plants also must be capable of measuring

150 C condensate flows of 1,200 1/s with accuracies of 0.1%. Additionally, limited natural resources and increased competition for fresh

water between power generation utilities,

industrial users, and agricultural water

suppliers requires improved accuracies of

field measurements.

To meet these needs, the NBS fluid flow

program includes extension of measurement

capability with emphasis on flow ranges

encountered in new regulatory acts, error

analysis in field measurements, meter performance evaluation for improved accuracies, and

maintenance of contact with the user commu- nity through conferences and correspondence.

24
NBSIR 75-931

THE NATIONAL MEASUREMENT SYSTEM FOR PRESSURE

Peter L.M. Heydemann

NBS Heat Division

April 1975

EXECUTIVE SUMMARY

The field of this study is the measurement

of pressure and vacuum. This field has developed from humble beginnings in the laboratory

of Evangelista Torricelli in 1644 to one that

encompasses practically all manufacturing

processes, the operation of many types of

machines, important scientific endeavors and our daily life. Industrial applications

cover 17 decades of pressure and science adds

another five. Within its range are billiondollar industries using pressure or vacuum

in a significant way to make or control semiconductors, radiators, beer cans, aircraft,

automobile tires, missiles, freeze dried food,

power plants and many other products or manu- facturing activities. Savings of great economic significance can be achieved through accurate measurements of pressure. The safety of

aircraft and of nuclear reactors is ensured

through, among others, pressure measurements.

A significant part of the measurements in this system are referred to NBS primary standards mainly through the instrumentation industry. NBS calibration services now cover about

five decades of pressure and an expansion to seven decades is planned for the near future.

The calibration services are based on a number

of primary standards, whose accuracy and precision are adequate for most purposes and work

continues to update and improve these standards. The dissemination of accurate measurements into the field is not always satisfactory. Large uncertainties added in the calibration chains are due to inadequate technical

and mathematical procedures, lack of good

transfer standards and lack of training of the

personnel involved. The calibration services

are backed up by training of industrial personnel, preparation of technical manuals and

reports, data evaluation service, laboratory

evaluation service and extensive consultations.

All of these back-up services were prompted by

early results from this investigation.

The field of pressure measurements is currently undergoing rapid changes through

the introduction of new types of measuring

instruments, through an expansion of the

range of pressures used in industry and

through the requirement for lower uncertainties. There is close cooperation between

NBS and the professional and engineering

societies on the development of the necessary measurement standards and test codes.

Increased awareness of possible safety

problems with gages and transducers, and

particularly with high pressure vessels was prompted by the Occupational Safety and

Health Act. Here again NBS is cooperating

with the concerned parties to provide the

necessary engineering standards. All of

these activities tend to lead to an infrastructure that is more strongly focused on the primary standards of pressure at NBS and

the related dissemination services.

A critical need, involving the safety of

people, is felt in the pressure range required

for the calibration of aircraft altimeters.

No central standards are presently available

to ensure uniform measurements throughout

this country and the rest of the world in

this important range. A new standard is,

however, under construction. Also, a measurement assurance program is under study to bring this area under control. Similar problems appear to exist with the nuclear breeder

reactor program and measures to bring this

under control are being discussed.

A Delphi technology forecast was undertaken to determine the need for vacuum measurements, which are not provided by NBS. This study is not complete, but it has provided valuable information for planning and

management decision making. Of approximately 125 randomly selected members of the

American Vacuum Society, 68% stated that thev

require vacuum calibrations in the range 10' to 10^ Pa with an uncertainty of 0.1%, or better, now. 42% now require vacuum meas- urements to better than 1% in the range 10"^

to 10-4 Pa. A much larger percentage of

experts in various fields of vacuum measurements foresee these needs for the immediate

future. The most demanding requirements for vacuum measurements were found in the manu- facture of semiconductors, in the space industry and in the vacuum instrumentation industry for the calibration of standard leaks

and the measurement of pumping speeds. It

is not surprising that in these industries,

which represent a production volume of more

than $6 billion, the average standards laboratory spends more than $130,000 annually

on vacuum measurements. NBS does not maintain any vacuum standards, but research

leading to the development of new low and

medium range vacuum standards is carried

out.

25

NBSIR 75-932 THE NATIONAL TEMPERATURE MEASUREMENT SYSTEM

J. F. Schooley

NBS Heat Division

March 1975

EXECUTIVE SUMMARY

Temperature is a well-defined, basic

scale quantity. It is perhaps the most

commonly-measured of all the physical units

(the possible exception being that of time).

This very ubiquity, however, has a double

effect. We desire (in principle) that we should have access to very accurate thermometry, but, on the other hand, we tend to take the measurements for granted, so that

our practice of thermometry is often of

poorer accuracy than we suspect.

The direct temperature measurement and

control industry is a large one by any

standards, including several dozen multimillion dollar firms. The amount of

economic leverage which thermometry exercises is multiplied greatly, however, by

the fact that good thermometry is essential

to the commercial success of many industries,

such as semiconductor, steel, chemicals and

plastics manufacturing, medical testing and care, and precision instrument manufacture

and use. Temperature is acquiring a new urgency in other areas as well, with the

tremendous demand for new sources of energy;

with the more stringent pollution and

efficiency requirements under consideration

for automobiles and aircraft; with the heavy

new demands for safety and output being

placed on nuclear power reactors; and with

the desire to map and exploit the ocean's

depths

.

In briefest terms, NBS is meeting the

heaviest of today's demands. The temperature scale is known and can be transmitted

on demand with an accuracy which is satisfactory for most purposes in the range 20-

1300 K. The calibration services offered by

NBS for platinum resistance thermometers,

for liquid-in-glass thermometers, and for

thermocouples answer most of the direct

needs for accuracy in that range.

Yet many human activities suffer a lack

of adequate thermometry, even in the same 20-1300 K range. The particular reasons for

this situation are numerous, but they come

down to a few general problems:

1) Adequate thermometry exists, but it

is not applied to the problem. The

whole field of practical medicine

suffers from this difficulty.

2) The type of measurement which is needed is not one for which a calibration rationale exists. Fastresponse, hostile environment, and

geometrical ly-constrained thermometry

requirements exist in many fields of

endeavor; many of these are noted in

the full report.

3) The calibration procedure which exists is too expensive to justify,

considering the economics of the

activity. The homely drugstore

thermometer is an example of this problem—a $10 calibration of a $1

thermometer is simply impractical.

Adding to these problems those which

exist where the temperature scale is not

adequate to today's needs gives one a fair

picture of the opportunities which lie before NBS in thermometry today.

Again in brief terms, NBS thermometry programs lie in several general areas:

1) Generate an adequate scale below 20 K and above 1300 K. 2) Devise calibration and temperature

standardization procedures which will

solve people's problems, rather than

simply transmitting the highest

attainable accuracy.

3) Participate in the development of

thermometry methods in areas where

glaring weaknesses exist.

The NBS temperature measurement activities

impinge on the U. S. temperature measurement

system directly in a multitude of ways. The

most obvious, of course, is through the

calibration of precise temperature sensors.

A second interaction is through NBS participation on voluntary standards committees;

that is a quite important activity, because

it serves both to communicate to others

expertise and data originating at NBS and to alert the NBS staff to problem areas. A third major interaction with the temperature

community arises through NBS staff participation in the development of measurement

methods —in general, this interaction occurs directly with one or more technical

thermometry groups in industrial or scientific

laboratories. Many such instances are detailed in the report.

The National Measurement System study has

been a valuable tool in our effort to focus our limited resources on the most pressing

and susceptible problems. We intend to con- tinue to use this approach to assess and,

if necessary, to modify the NBS temperature

program.

27

NBSIR 75-933

A STUDY OF THE NATIONAL HUMIDITY AND MOISTURE MEASUREMENT SYSTEM

Arnold Wexler

NBS Heat Division

March 1975

EXECUTIVE SUMMARY

Water in the form of vapor and liquid

(moisture) is an ubiquitous substance that

pervades our earth affecting almost every

material, process, device, instrument and

product. Life itself depends on its presence. It plays an important role in the

scientific disciplines, in many branches of

engineering, in medicine, meteorology, and

agriculture, and in such diverse industrial

fields as air conditioning, drying, refrigeration, storage, food processing, electronics and communications. Because of the

innate interaction between water and its

surroundings, and the pervasive effect water

has, it is essential to be able to determine

or adjust the amount present, that is, to be

able to measure and control its quantity in

a given environment or material.

Instruments which measure water content

in the vapor phase are classified as hygrometers; those that measure water content in

the liquid phase, that is, that measure

moisture in liquids and solids, are classified as moisture meters. This study delineates the infrastructure of the humidity

and moisture measurement system and the

interrelationships that exist between the

fundamental units, the standards, the calibration procedures, the instruments, and the users. It examines the impact that this

measurement system has on economic, scientific, social and industrial aspects of our national life. Finally, it identifies and

analyzes certain deficiencies and needs in

the National Measurement System.

The primary responsibility of NBS is to provide the central basis for the National

Measurement System, to coordinate that sys- tem nationally and with those of other

nations, and to furnish the essential ser- vices leading to accurate and uniform meas- urements throughout the USA. The study

shows that the NBS base for the humidity

measurement system comprises five primary

elements: (1) measurements research, (2)

standards development, (3) development of

special instruments for specific end uses,

(4) prototype development and construction

of new instruments to meet the needs for

secondary standards, and (5) issuance of

publications, such as monographs, to provide

users with information on instruments,

methods of measurement, sources of accuracy,

NBS capabilities, etc. Coordination is

achieved through the dissemination of information, data, techniques, methods, procedures,

references and reprints to Government, industry, colleges, universities, institutes, industrial laboratories, foreign governments

and foreign organizations. One important

link in the coordination chain is the presentation of tutorial lectures before professional societies, workshops, seminars,

clinics, and training courses. Direct ser- vices are offered through (1) calibration of

plant and laboratory standards, (2) tests

for compliance with government procurement

specifications, (3) evaluation and testing

of sensors for special government programs

and (4) tests for the public when commercial,

industrial, or university laboratories cannot meet required needs.

This study categorizes and classifies the

instrumentation in current use in terms of

principles of operation, commercial sources,

and end uses. At least twenty-four distinct

types of humidity instruments and controls

are known to be made in the USA. These are available from more than 100 manufacturers.

Information gathered so far indicates

that the annual business volume of the identifiable instrumentation industry for humidity and moisture measurement and control is

of the order of 35 to 70 million dollars.

This instrumentation impacts on a great

diversity of disciplines, industries and

technologies, creating a second order effect

that is estimated to run into the billions.

In the process industries such parameters

as temperature, flow, liquid level, pressure,

chemical composition, density, viscosity,

humidity and moisture are monitored and regulated. It is estimated that of the total

number of such measurements, humidity constitutes 3.5 percent and moisture 0.7 percent.

The economic loss resulting from measurement

inaccuracies is substantial. For example,

the uncertainties in the determination of

moisture in grain, such as corn, can result

in annual dollar losses from excess moisture

or excess drying of $135 to 375 million.

The amount of water in a material is of

vital commercial concern-- in buying, selling,

shipping, etc. It greatly affects the
properties of materials. The relative humidity of the environment and the moisture con- tent of a given material must be controlled

for many industrial processes and for the

production of a great many products. Only

through such control can such factors as product uniformity, quality, and process

economy be achieved. Such control contributes to the conservation of fuel and energy

in drying processes. In the testing of many

materials for strength, performance, life,

etc. , humidity control plays a paramount

role. For example, a review of American

Society for Testing and Materials (ASTM)

standards has identified at least 45 categories of materials that must be conditioned

in cabinets or rooms prior to test and 84

categories of materials covered by procedures

for the measurement of moisture content.

Other organizations having standards, specifications or procedures involving humidity

or moisture measurement and control include

Air Conditioning and Refrigeration Institute

(ARI), American National Standards Institute

(ANSI), American Petroleum Institute (API),

American Society for Agricultural Engineers

(ASAE), American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc. (ASHRAE), American Society of Mechanical

Engineers (ASME), Association of Official

Analytical Chemists (AOAC), Cooling Tower

Institute (CTI), U. S. Department of Agriculture (USDA), U. S. Department of Defense

(DOD), Technical Associations of the Pulp

and Paper Industry (TAPPI), Underwriters

Laboratories (UL), International Organization for Standardization (ISO), International Electrotechnical Commission (lEC),

U. S. Department of Commerce--National

Oceanographic and Atmospheric Administration

(NOAA), and the World Meteorological Organization (WMO).

This study has disclosed several shortcomings and deficiencies in the National

Measurement System. As an example, there

are no national standards for moisture measurements. Various technologies have established recommended practices or specifications through voluntary documentary organizations such as The American Society for Testing and Materials. In the agricultural

field, the U. S. Department of Agriculture

and the Association of Official Analytical

Chemists have established reference methods

for determining moisture in specific materials, yet none is directly traceable to NBS.

As a result of this study, and in re- sponse to requests from state weight and measures officials, NBS has initiated a program with the broad goal of providing

the central basis within the USA of a con- sistent measurement system for moisture in

materials and to provide essential moisture

measurement services throughout the

Nation.

30
NBSIR 75-934

THE NATIONAL MEASUREMENT SYSTEM FOR THERMODYNAMIC PROPERTIES OF FLUIDS

Max Klein

NBS Heat Division

August 1975

EXECUTIVE SUMMARY

This report describes the national mea- surement system for the generation of data

on the thermodynamic properties of fluids,

specifically the thermosphysical properties

such as vapor pressure, heat capacity, and

the equation of state. The institutional

and human elements of the system consist of

producers, evaluators, and users of such data.

Thermodynamics describes the transformation of energy and especially its interconversion as heat and work and its involvement

in chemical prodesses. Fluids are ideal

media for applied thermodynamic purposes, so that knowledge of their thermodynamic properties is of high importance. Thermodynamics is a subject of enormous generality

whose utility in science and technology is

is all-pervasive. It plays a central role

in many disciplines of physics, chemistry,

engineering, and the life sciences. Technologies impacted include the design of

engines for producing work (e.g., steam tur- bines), processes for purification through

phase separation (e.g., distillation and

selective freezing), the design of chemical

reaction systems (e.g., as used in petroleum

cracking and in heating), and the design of means for obtaining very low temperatures

(e.g., as used for preserving material, food

and medicine, and for obtaining special low

temperature properties like superconductivity). Industries impacted include chemicals,

petroleum, natural gas, electric power generation, aircraft production, and transportation. Societal problems affected include the

maintenance of air and water quality, the

production, distribution and consumption of

food and energy, the disposition of waste,

the design and maintenance of health care facilities, and the efficient use of mineral

and material resources. The pervasive influence of thermodynamics makes the assignment of resources to producing outputs for

this measurement system very cost effective

since a small investment can have broad

economic and social impacts.

While economic impacts can be described,

a detailed assignment of meaningful dollar

values is difficult. Scientific and technological impacts of any particular data

generation effort may be equally hard to document. Outputs of such efforts are typically freely available to all comers

(e.g., in the technical journals) and there

is no easy way to know who they are and how

they may be using the outputs. The report

contains a number of detailed examples of the

economic role played by accurate outputs

from this system. By implication, these

describe the economic role of the NBS con- tributions to this measurement system since

NBS outputs are generally of the highest

accuracy.

The total amount of data demanded from

this measurement system by its users is

truly astronomical and cannot possibly be

produced by measurement alone. Substances

of interest are normally mixtures and often

consist of several components, sometimes

distributed over several phases. Data are usually needed for a wide range of compositions, with a range of temperatures and

pressures needed for each, composition.

Because of this large data need, the development of theoretical models of varying degrees

of empiricism plays an important role in the

system. Such models can be used in a wide

variety of applications, perhaps the most

important of which are for the rapid estimation of the feasibility of industrial pro- cesses, for control of industrial processes

during operation, and in the analysis of ex- perimental measurement designs. Extrapolations are often made to conditions other

than those for which data are available or

to material systems for which no measured

data exist. Such extrapolations must be

based on accurate models, which, in turn,

require in their development data of the

highest accuracy on representative substances . Because material and energy supplies have,

until recently, been abundant and cheap,

highest accuracy has not been a major concern

in the design of most industrial systems

which require the application of thermodynamics. However, because of current needs

to conserve energy and material and to predict the environmental impact of plants before their construction, demands can now be

expected for designs and analyses based on thermodynamic data of the highest accuracy.

31
Currently, the best attainable accuracies

for the thermophysical properties under con- sideration lie in the range 0.01-0.5 percent.

Because measurement of these properties is

difficult and hard to automate, the accuracy

attainable is generally much less than that

needed. By implication, this defines a strong role for NBS in the development of

improved national measurement capabilities.

Needs of the system are many and include

the development of rapid automated measure- ment methods (especially for pressure and

composition), the production of data on a wide selection of mixtures carefully chosen

to provide insight into the role of molecular

properties, the development of methods for

describing the entire PVTX surface of fluid

mixtures of various kinds, the development

of accurate measurement techniques for transient equilibrium measurements and those

under extreme environmental conditions, the

development and application of new techniques

(especially optical ones), the development

of fluid theories for systems of non- spherical molecules, and the production of

data and understanding regarding nucleation

phenomena.

The basis for an NBS role in a measurement

system whose outputs are so directly involved

in technology and fundamental science is

clearly stated in its organic act. The NBS

has, since its inception, indeed been active

in the generation of thermodynamic data,

having produced benchmark data and publications, some of which still play central

roles even after over half a century after

publication. NBS outputs have provided the

knowledge to support vast improvements in

entire industries, such as agriculture

(ammonia fertilizer), electric power generation (steam), plastics (ethylene), and

steel (oxygen). The acquisition of data of

sufficient quality to be called reference

data is still so time consuming as to be

rarely undertaken outside a laboratory like

NBS, hence the especially strong NBS role

at the highest level of data accuracy.

The NBS appears to be doing a good job of

communicating with the user community. Some

improvement is needed in developing communications with the portion of the user com- munity at the ultimate use point. Much has

already been done on this. Meetings between

users and producers of data are being

planned.

Satisfying the entire set of system

needs will be difficult for the producer

part of the system. A concerted effort will

first be needed to overcome the negative

effects of declines in recent years. These

declines resulted from an emphasis on short

range research (whereas the major problems

of the system are long range), a lack of

incentive among the mission-oriented government agencies for the support of research

aimed at developing new experimental and

theoretical techniques, a reduction of the

number of students available at universities

and the difficulty of predicting the future

availability of students, and a reduction of

funding for basic research over the past

several years.

These needs contain much which properly

fits the NBS mission. NBS resources are, however, insufficient to cover them even with rather extensive reprogramming, and

selection is needed. The development of

measurement techniques for rapid data taking

the taking of needed data, and the development of predictive theories of mixtures have

been taken as programs for NBS concern in

the near future, provided sufficient NBS resources are available.

NBS resources available for producing

outputs in this measurement system are small

and have other programmatic demands on them.

Approximately 50 percent of the current

financial support comes from outside sources These resources, while supporting outputs

into the measurement system, nevertheless

do this from the point of view of the organizations supplying the funds. This reduces

considerably the ability of the NBS to design programs according to the needs of

the measurement system as a whole. With

growing demands expected, NBS resources ap- plied to this measurement system will need

to be increased in the near future.

32
NBSIR 75-825 THE NATIONAL MEASUREMENT SYSTEM FOR CRYOGENICS

Thomas M. Flynn

NBS Cryogenics Division

August 1975

EXECUTIVE SUMMARY

The National Bureau of Standards is not responsible for only one unit of measurement,

or even a set of measurements. Rather, the

legislative mandate calls for NBS to provide

a base for such a system, coordinate that

system, and furnish essential services. Thus

it is the responsibility of NBS to assure the

proper functioning of the Nation's system of

physical measurement, the National Measurement System. Accordingly, the present

microstudy was conducted to examine and

document the way in which the NBS Cryogenics

Division is meeting its particular responsibility to assure the proper functioning of

our system of cryogenic measurement.

The Cryogenics Division of NBS provides

the measurement and data services that support a whole technology. Almost every category of measurement and data service is

offered that NBS as a whole provides: not

just an instrumentation system (including,

for example, pressure, temperature, density,

liquid level, flow rate, etc.), but also

properties of fluids (both thermodynamic and

transport properties); properties of solids

(thermal, mechanical, and electrical); an interface with the users through systems

integration, and advisory and consulting

services; and our own dissemination network

through the Cryogenic Data Center.

This study shows that there are three

specific emerging technologies within this

broad area of Cryogenics which need a com- plete and consistent system of measurements

and data.

For instance, a comprehensive measurement

system for liquefied natural gas needs to be

developed, with special emphasis on quantity

gaging in storage, flow-metering for both mass and heating value, and basic measurements of thermal and mechanical properties

of structural materials.

Basic measurements and data are required

to support the development of hydrogen as a fuel, to improve hydrogen liquefaction efficiency, to recover liquefaction energy, to document hydrogen-compatible materials of

construction, to develop improved insulation

materials, plus measurement tools and techniques for the eventual commercial exchange

of liquid hydrogen.

Superconductivity connects cryogenic

measurements and data to the electrical power

industry, for power transmission, generation,

and storage. Knowledge needed here includes

heat transfer rates, behavior of helium re- frigerant flow systems, and the degradation

of the superconductors with time and stress. Other practical uses of superconductivity are becoming apparent, such as the application of

Superconducting QUantum Interference Devices

(SQUIDs) to problems ranging from mineral

prospecting to magnetocardiography . Accordingly, the needs to support this technology

encompass instruments and techniques for

physical measurements plus a technical data

base.

The technologies discussed above show the

importance of cryogenics in commerce in the

U.S. today, and also show its truly diverse

applications. If there were a "General

Cryogenics Corporation" like a General

Motors, it would appear in the top 10% of the

Fortune list of the 500 largest U.S. Industrial Corporations. But it is important to note that there is not a "Cryogenics Corporation", per se. Cryogenics is an infrastructure industry. Similarly, the national

system of cryogenic measurements is an infrastructure of cryogenic technology itself.

The crucial question of this report is, how

well does the measurement and data structure

support the technology as a whole?

This study shows that some parts of the

cryogenic measurement system seem to be

characterized by adequate services and quality assurance (cryogenic temperature mea- surements, for instance). It appears one should have less confidence in other parts of

the system. Pressure measurements, for

instance, which are probably the measurement

most widely made in all of cryogenics,

appear not nearly so well supported, especially pressure measurements in extreme

environments. Attention by NBS to these

issues is in order.

Especially apparent at this time is the

need for a different kind of measurement,

namely one that describes the quality or availability of the commodity. Specifically,

we refer not so much to the flow measurement

of liquefied natural gas, for example, as to the need to measure its potential heating

value.

33
It appears that one component of the problem of cryogenic measurement is that the

field is somewhat static. There has been no concerted national effort since the peak of

the space program.

A second part of the problem arises from

the way cryogenic measurements fit into the

National Measurement System. As long as only

a single agency or one sector of our economy

(National Aeronautics and Space Administration, the aerospace industry) was using es- sentially all of the results of its own meas- surements, then that part of the National

Measurement System was internally consistent

and in harmony with itself. Now, however,

cryogenics is becoming more commercialized

and moving to the market place, and thus

external consistency as well as internal

consistency is required to make this part of

the National Measurement System work.

The third part of the problem is perhaps a derivative of the first. Because the field

is relatively static, a crucial question is

not being asked: are there predictable technological developments that will either

create a need for new cryogenic instruments,

or possibly provide an altogether new mea- surement means?

Certain parts of the cryogenic measurement

system at the national level seem to be disconnected, or working independently of one another at this time. For instance, our perception is that the U.S. Coast Guard has

the necessary authority to regulate certain

aspects of liquefied natural gas transportation by setting certain physical standards,

measurement codes, and practices. They may do

this without necessarily having recourse to the NBS. Other national authorities, especially in the area of public safety come to mind. Accordingly, it appears that this part

of the measurement system is disjointed.

There is no objective reason why it should

remain so. It would be in accord with the

NBS mission and tradition to pursue these

issues and resolve them.

A goal of this study was to achieve both

conceptual breadth and depth by examining our

role in the national measurement system as a whole, and illustrating this role with a specific case study, the liquid nitrogen

flowmetering program. This program was instigated by the needs of state weights and measures officials, the industry concerned,

and the public for confidence in the custody

transfer of liquid nitrogen. This effort used

nearly every competence and capability that

NBS has developed: measurement services

(tests and calibrations of meters), property

data (thermodynamic property data for cryogenic fluids), standard codes and practices

(Handbook 44), dissemination services (Office

of Weights and Measures, the National Conference of Weights and Measures), and both

voluntary and regulatory standards activities

(through the most relevant industry group

concerned - the Compressed Gas Association,

and by adoption in state codes).

The general conclusion of this study is

that the cryogenic measurement system is

doing its job adequately at reasonable cost. There is no widespread feeling of inadequacy,

such as that which led to the creation of the

National Bureau of Standards seventy-five

years ago. On the other hand, there are both

systematic and specific deficiencies that can

and should be corrected. Further, there are

several areas in which the cryogenic measurement system will be subjected to severe

strains in the foreseeable future, unless

appropriate responsive steps are taken soon. Specific needs and responses, which are

only summarized here, are documented within

the body of the report.

34
NBSIR 75-935

THE NATIONAL MEASUREMENT SYSTEM FOR ELECTRICITY

Norman B. Belecki, Bernadine L. Dunfee, and Oskars Petersons

NBS Electricity Division

October 1975

EXECUTIVE SUMMARY

Electrical measurements are of critical

importance due to the universal use of

electricity as the primary means for the

transmission and control of energy and data.

The National Electrical Measurement System

is that set of laboratories, organizations,

documents, and people which make possible

and are responsible for all electrical

measurements made in the U.S. at all levels

of accuracy. This document summarizes the

results of a three-year study of that system.

The structure of the system may be con- ceived as having a number of components,

each serving a particular sector of society

and each having distinct characteristics

reflecting differing requirements. Tv/o major components exist: the industrial electronics component and the electric power

industry component. There are a number of

minor parts as wel 1

.

Electrical measurements in the system's

industrial electronics component are used

to insure quality and reliability of

materials and manufactured products, to provide for interchangeabi 1 i ty of components

and parts, and to control manufacturing

processes.

This component can also be further

sub-divided into two general areas: the

measurement-intensive industry segment and

the general industry segment. Measurementintensive industry and ite measurement

system are characterized by high technology

and the need for a very high degree of product reliability. Thus, included in this

portion of the system are the instrumentation, aerospace, defense, communication,

computer, and electronic component

industries. Measurement accuracy within

this segment is insured by a hierarchical

laboratory system in each organization.

Test equipment used for quality and process

control is calibrated periodically using

precision instruments which are in turn calibrated by comparison with primary standards in the corporate standards laboratory.

These corporate primary standards are then

periodically calibrated at the National

Bureau of Standards or i ntercompared

regularly with standards which have been so calibrated. This system, which in large

organizations can have a complex hierarchy

of laboratories, is primarily the result of

the quality control requirements of DOD,

GSA, and NASA procurement contracts and

the requirements of regulatory agencies such

as EPA and OSHA.

In the general industry segment of the

system, quality control requirements are usually less stringent than in the high

technology segment; accuracies are generally

lower; and the manufacturing processes are

less affected by absolute accuracy of

measurements. Thus, organizations in this

portion of the system are inclined to buy

calibration and repair services from

instrumentation manufacturers, large

corporate laboratories in the aerospace

industry, or companies specializing in

calibration and repair work. As previously

noted, each of these generally maintains a rigid, well-defined measurement support

system.

There appears to be a number of problems

and shortcomings in the industrial electronics component of the system. Among

the most important are a lack of standards

(written and artifact) for the support of

dynamic, high-speed electrical measuring

instruments and automated test systems;

the non-availability in certain areas of

procedures and test techniques of guaranteed

reliability; a potential future shortage of

competent measurement personnel; a failure

on the part of some people in the system

to perceive that calibration is not always

a sufficient condition for assurance of

measurement quality; and an inherent

rigidity in the government contractural

requirements which stifles innovative

approaches to measurement problems.

The electric power industry segment of

the National Electrical Measurement System

can also be divided into two parts: operational and research for improved electric

power transmission and distribution. Electrical measurements play an important role

in the day-to-day operation of the nation's

electric power systems. They are used to control the generation and transmission of

35
I

electricity, to provide a basis for equitable exchange (energy metering), and for

testing machinery and equipment supplied

to the power companies.

Measurement support for both of these

areas is generally provided by the measurement laboratories of power companies and

those of the electrical equipment manufacturers. In the energy metering area, many

of the state and local public utility com- missions which regulate the power companies

require acceptance testing of watthour

meters as well as retesting of older meters.

NBS calibration of physical standards and

electrical apparatus, both at NBS and in

the power companies' and manufacturer's

laboratories, insures the overall integrity

of the system.

Most of the industry - both utilities

and manufacturers - is adequately equipped

to measure traditional quantities such as current and voltage at levels up to 15 kilovolts. Fewer companies, especially in the

utility sector, have capabilities above

200 kilovolts. At extra high voltage (EHV)

and ultra high voltage (UHV), the utility

companies, with rare exceptions, have little

measurement and calibration capability.

Such capability, however, does exist with

the manufacturers of large electrical equipment. With respect to non-traditional

quantities, such as high transient voltages

and currents, measurement capability is

generally available only with the large

equipment manufacturers.

The quality and consistency of electric

power system-related measurements, including

traceability to NBS-maintained standards,

follow the above pattern of measurement

capability. Whenever the calibrations are relatively simple and inexpensive, and if

there is also regulatory incentive to do

adequate work, the system is in excellent

condition. A good example is watthour

meter calibrations. But for higher voltage,

and especially for non-conventional measurements where the calibrations are difficult

to perform and reliable methods are not always readily available, the system has

deficiencies. Included in this category are

EHV and UHV steady state measurements, and

transient measurements in general.

Electricity will become the predominant

form of energy in use before the end of the

century. Consequently, a large research and

development effort funded by the Energy

Research and Development Administration and

the Electric Power Research Institute is

being directed at ways to increase the transmission capability and efficiency of the

country's electric power systems. New high

voltage and electrical-related measurements

are required as transmission technology ad- vances. Examples of the new technologies

include cryogenic transmission systems, UHV

overhead lines, compressed-gas insulated

substations, and high-voltage direct-current

transmission. Each is a relatively measure- ment-intensive, emerging technology area. While some older types of measurement

methodologies can be adapted for these new

areas, generally they cannot and some significant deficiencies now exist including

accelerated aging tests of electrical insulation, and traceability to national

standards for impulse measurements.

Two important additional components of

the National Electrical Measurement System

are associated with the scientific community

and consumer electronics. Measurements made

in laboratories not under DOD or NASA con- tract are generally supported by local

instrumentation shops. In contrast with

the usual practice in the industrial electronics component, periodic recal ibration is

unusual - calibration is generally performed only before and after a crucial

experiment, or as part of a special

maintenance effort. Measurements in support of consumer electronics, such as TV,

stereo systems, citizen band and amateur

radio, auto electronics, and general electrical work are usually of low accuracy. Consequently, manufacturers' claims of test

equipment accuracy are accepted until malfunction occurs. This portion of the system

has few, if any, serious technical problems.

In summary, the Electricity Division of

NBS provides the basis for that uniform

system of electrical measurement in the

U.S. which permits equity in trade, interchangeability of components, the transmission and distribution of electric power, a means of maintenance for electronic equipment, the ability to control the quality of

production, and the general advance of

science and technology. This is achieved by

developing improved means for realizing,

maintaining, and disseminating the basic

electrical units; by calibrating electrical

standards, instruments, and systems for

industry, government, and the academic com- munity; by developing new instrumentation

and measurement methods; by obtaining basic

data and determining fundamental constants

related to the electrical units; by ensuring

that electrical m asurements carried out in

the U.S. are consistent with those made in

other countries; and by providing advisory

and consultative services.

36
THE NATIONAL ELECTROMAGNETICS MEASUREMENT SYSTEM

Robert A. Kamper

Electromagnetics Division

July 1976

EXECUTIVE SUMMARY

Electromagnetic technology is the practical

exploitation of electromagnetic waves, propagating either in transmission lines or freely

through the atmosphere, and occupying a very

wide spectrum of frequencies. It has grown up within the limitations set by nature.

In the range of frequencies below a few

hundred MHz components are cheap, most antennas are not very directional, and the background is noisy. This part of the spectrum is

very heavily used by telecommunication systems,

both for business and for pleasure. High performance brings no significant advantages to these systems, so accurate measurements of the

characteristics of components are rarely called

for. The FCC keeps order among the various

users of the spectrum by assigning frequencies,

which are checked routinely, and power levels,

which are rarely enforced. Many electronic

systems, such as computers and servo control

systems, are unintentional transmitters and re- ceivers of electromagnetic radiation in this

part of the spectrum. Interference is therefore a severe problem, that calls for repeatable measurements of complex, fluctuating quantities, to be used as the basis for the assignment of responsibility for its resolution.

An extreme case of electromagnetics interference occurs when fields are strong enough

to injure people. This is a real danger with

radio and TV transmitters and leaking microwave

ovens. Exposure to hazardous fields is regulated by OSHA, supported by measurements of the

field levels in question.

Another aspect of electromagnetic waves in

this part of the spectrum that is not yet fully

exploited is their ability to penetrate to useful distances in rock, soil, concrete, water,

etc., to probe structures of these materials to supply information for civil engineering or mining. This will require extensions in the

formulation of electromagnetic theory and the

acquisition of a base of data on the properties

of materials, which are the subjects of re- search that is in progress now. At frequencies in the range from about 300

MHz to 30 GHz we find a higher preponderance

of more sophisticated systems. Here wavelengths are short enough that highly directional antennas are quite common. The background noise is low enough to enable systems to operate with very weak signals. This range

of frequency is used by most of the radar

systems on which modern navigation depends,

both for ships and for airplanes. Improved

systems such as discrete address microwave

beacons are under development for air navigation. Microwave systems are under development for landing in conditions of poor

visibility. The armed services use radar

for the automatic guidance of terrainfollowing aircraft and of weapons, as well

as for searching for the enemy. On the highways, the police use radar for speed control.

In addition to radar, this region of the

spectrum is used for telecommunications.

Most long-distance telephone traffic is carried by microwave beams between repeater sta- tions in direct line of sight with each other.

Satellite communications are a rapidly growing

business. The driving force in the expansion

of the telecommunications industry is the

trend towards having distant computers com- municate directly with one another. In addition to demanding large channel capacity,

computers and the associated digital technology encourage a trend towards digital com- munication, and separating different messages

in time rather than frequency. This also has

advantages for transmitting the voice, in the

efficiency of use of channel capacity and the

quality of the transmission. This is generating a new demand for time-domain measurements.

The electromagnetic systems that use this part

of the spectrum tend to be expensive, but to repay their expense with very high performance

if they are carefully designed and maintained.

For this they require the support of accurate

measurements.

The region of the spectrum from 30 GHz to 300 GHz is presently regarded mainly as an overflow for users of the crowded channels at lower frequency. Components become much more

expensive and less efficient in this region,

and the atmosphere has strong absorption

bands. The most significant commercial system, under development in several countries,

is for telecommunication at 90 GHz through

oversize circular waveguides.

There is not much commercial activity at frequencies between 300 GHz and 100 THz. There is much scientific activity in the development of lasers, and the world's most

accurate spectroscopy is done in this region.

Surely commercial or military exploitation

will follow, especially of the COo laser,

which can already be made to be cheap, efficient, and powerful. There is some activity

with military funding to develop it into a weapon, and the most significant measurements

to be made are of its beam profile and energy

output.

37
The near infrared and visible parts of the

spectrum are used for all the activities that

the possession of eyesight has suggested to

us, in addition to some that had to await the

development of instruments. These include the

remote sensing of temperature by radiometry,

and all the possible applications of visible

lasers, such as alignment and measurement of

linear displacement, micro-machining and sur- gery, holography, information processing (especially Fourier transformation), video disc

recording, and automatic checking of groceries

at the supermarket. Obviously, a very diverse

collection of measurements must be made to support these activities, not the least important

of which is the measurement of power and energy

to regulate safety.

One newly developing optical technology

that has much in common with the corresponding

microwave techniques is telecommunication

through optical fibers and the integrated

electro-optical systems that will be used for

transmitters and receivers. These will call

for all the types of measurement that have been

made on microwave systems, translated to a different region of the spectrum with different

difficulties and conveniences.

In general, electromagnetic measurements do not attempt to attain the degree of accuracy

that is possible for DC electrical measurements.

Practical systems must be designed to tolerate

variations of a few percent in circuit parameters due to instability of components and var- iations in operating conditions. Therefore

measurements with uncertainty less than 0.1%

are rdire]y called for.

Another striking feature of the electromagnetic scene is the high demand for measurements

of dimensionless quantitites, such as attenuation, phase angle, reflection coefficient, and

antenna gain. There are national standards and

calibration services for many of these, but the

trend is to replace them with self-calibration

techniques.

Reference to the SI base units is tempered

by the modest requirement for accuracy. The

ohm can readily be independently realized in

the form of a length of transmission line whose

characteristic impedance can be calculated from

its geometry. The amplitude of waves is

determined by measuring power, voltage,

current, electric or magnetic field. The

essential step in all these measurements is

the conversion of the quantity to be measured to an equivalent DC quantity. Reference of the latter to the basic SI units is

a trivial step at the level of accuracy

required.

The foreseeable future challenges to the

National Electromagnetic Measurement System

will come from: heavier use of the "underdeveloped" parts of the spectrum, such as millimeter waves, and the infrared and visible, for communication; wider use of multimode transmission lines; the quest for opti- mum use of time division multiplexing and

the consequent need for the precise characterization of the time-domain response of

devices, systems, and materials; and the new forms of interference that all this activity will generate.

38
NBSIR 75-937

THE NATIONAL MEASUREMENT SYSTEM FOR MEDICAL ULTRASONICS

P. A. Hu NBS Electromagne

February

EXECUTIVE SUMMARY

The medical applications of ultrasonics

have increased at a rapid rate during the

past five years. Ultrasonics is used for

diagnostics, therapy (diathermy) and surgery.

The most important of these is the diagnostic

applications. Recent advancements in signal

processing techniques and hardware have made

possible the conversion of ultrasonic images

to real-time optical images of good quality.

Systems employing complex phased arrays of

transducers are now in the laboratory stage

and will find their way to the practitioner

within the next two years. A large amount

of activity is going on in these developments

in university laboratories, manufacturers,

and non-profit organizations. The size of

the field of medical ultrasonics is estimated to be between $50M and $100M. These

figures include doctor's fees, research and

equipment production.

Reviews of the literature have uncovered

a considerable concern with regard to the

toxicity of ultrasonic waves on certain

parts of the body. Since ultrasonics is

widely used in fetal studies, a large amount

of the concern was in this area. Certain consumer groups (e.g., Ralph Nader) have

testified before congressional committees

detailing their concern over this new

medical tool.

Research into the toxic effects and

damage thresholds of ultrasonic radiation

are in progress at various research hospitals,

universities, etc. However, it is expected

to require several years before definitive,

quantitative results are obtained. In the

meantime, damage threshold measurements are hampered by a lack of physical standards.

Measurement consistency between various

researchers varies by an order of magnitude

in some cases. The National Measurement System as it

applies to medical ultrasonics is fragmented,

unco-ordinated and inadequate. Measurement capability for the more important

parameters, power, intensity, and beam

pattern, is mostly centered in development

laboratories, certain manufacturers, and

government laboratories. The Bureau of

Radiological Health (BRH, DHEW/FDA) maintains

measurement capability designed to aid in

their role as the regulatory agency under

provisions of the Radiation Health and Safety

Act of 1968. The Electromagnetics Division

of NBS began standards development three

years ago and now offer a limited calibration

service at 1 , 2, 3 and 5 MHz for total beam

39

json

:ics Division

1976

power. Also offered is a measurement service

for efficiency of high-Q quartz transducers

in the band 0.5 to 10 MHz. Accuracies at

NBS are 5% or better as compared to 10% to 15% in the field. A serious hindrance to more widespread standards dissemination is

the lack of a suitable transfer standard

device. It is believed that a low-cost,

rugged and reliable device can be developed

for use by both technical and non-technical

(medical ) personnel

.

National laboratories in foreign countries,

notably West Germany and Australia, have

developed standards for important ultrasonic

quantities and offer a more complete measurement service than does NBS at this time. At

the PTB in West Germany, for example, the

ultrasonics group consists of 15 people and

they have been working in the field for more

than 12 years.

As a result of announcement of NBS services

(August, 1974), numerous inquiries have been

received, calibrations have been performed,

and negotiations are in progress for intercomparisons with two leading university

laboratories. Intercomparisons with BRH

have been carried out and the importance of

this to that agency was quite significant in

that they were able to proceed with the preparation of regulatory documents. These

documents will prescribe that all ultrasonic

medical equipment be metered for power output

and that the accuracy of the metering be

within certain limits. This is expected to create a demand for NBS measurement services

from manufacturers who wish to insure that

their equipment meets BRH requirements.

Close cooperation and exchange of information is maintained between NBS and BRH. For example, information gained by BRH in

their field surveys and contacts with manufacturers is passed on to NBS. The BRH program in ultrasonics standards is aimed at development of working standards for use in

their regulatory role. They look to NBS for

development and maintenance of basic standards.

For the future, the Electromagnetics

Division has under development a precision

scanning system (computer controlled) to yield accurate measurements of field and

beam patterns of ultrasonic transducers

and arrays. This system is expected to become a major factor in solving measurement problems which now exist. A new calorimeter which is to serve as a basic

standard for power measurement, is nearing

completion. Thus, the potential impact of

NBS on the important field of medical ultrasonics appears to be substantial.

NBSIR 75-937

THE NATIONAL MEASUREMENT SYSTEM FOR ACOUSTICS

David S. I NBS Institute for

August

EXECUTIVE SUMMARY

Acoustics, the branch of science dealing

with sound, has become a field which plays

an important element in many aspects of our contemporary technological society. Acoustical measurements are performed in order to quantitatively characterize noise levels, to specify noise emissions, to specify the

acoustical properties of architectural materials, and to quantify and interpret human

response to sound, to name but a few examples.

This report describes acoustical measurement,

processes which are motivated by societal concern over noise and which are continuations or extensions of traditional acoustical

measurements.

Ultrasonic non-destructive evaluation has

evolved as an important relatively new application of acoustical technology in which

acoustical measurements are used to identify

and characterize flaws. These measurements

are performed in order to meet the increasingly severe requirements for mechanical integrity and reliability as well as pressures

for material conservation and increased productivity. The nature and importance of

these measurements are briefly described.

Although the report describes a diverse

range of acoustical measurement tools and

methods, there remain numerous acoustical

measurements not covered in this report.

These deliberate exclusions include such important fields as physiological acoustics,

physical acoustics, and underwater acoustics.

The deliberate exclusions of these topics was necessary in order to limit the scope of the

report and to direct attention to areas of

acoustics in which the necessity of obtaining

increased objective quantitative knowledge

has recently become apparent.

The principal user groups for noise measurements include various departments, agencies, or laboratories of Federal and State

governments; manufacturers of measurement

instrumentation, products for which noise

emissions are of immediate or potential concern, or architectural materials; acoustical

consultants, architects, and urban planners;

and university faculty and staff members

affiliated with research laboratories or speech and hearing clinics. Users of ultrasonic non-destructive evaluation equipment

include the aerospace, power generating.

allett

Basic Standards

1975

construction, metals production, auto manufacturing, metals fabrication, and railroad

industries

.

There are numerous identifiable social

,

technological, economic impacts for these

measurements. Measurement of noise is now

an important element in the protection of

society's hearing. Conduct of some ten to twenty million annual audiometric examinations will soon demonstrate an increased

level of awareness of noise and of the importance of hearing conservation in our society. Acoustical measurement processes

are explicitly involved in noise control and

hearing conservation. Economic impact is more difficult to assess quantitatively, and

a well-defined picture of the economic impact of acoustical measurements is not yet

avai lable.

The role of the National Bureau of Standard's acoustics activities within the infrastructure of the National Measurement System

is based primarily upon interactive processes

which constitute the inputs and outputs for

these activities. The substance of the interactive process consists of such elements as provision of and interchange of test and

calibration data or technical reports, or the

development of calibration and test procedures and measurement methodologies. Par- ticipants in this interactive process include standards organizations, professional

societies and universities, representatives

of foreign laboratories, and various industrial representatives (including trade

associations as well as individual manufacturers). The principal industries involved include those whose manufacturing

processes are inherently noisy, and those

whose products are required for noise abatement and control

.

Because of the increased legislative

attention given to noise and its control, and

of the consequent attention to the required

measurement methodologies, the adequacy of

these methodologies is now the subject of

intensive study, both within NBS and within

other Federal, State and local agencies.

The study indicates that there is a con- tinuing demand for improved accuracy and

precision in both the development and calibration of acoustical measurement instrumentation and in the evolution of improved

measurement methodologies. Provision of
services such as these has traditionally been

a strength of the NBS program in acoustics.

The study also illustrates that a significant

increase in the number and scope of legislative actions directed toward noise control

has taken place. It is likely that this

increase will continue, particularly as state

and local governments become active participants. Inconsistencies in the relevant re- quired measurements are apt to introduce

ambiguities into the legislative actions, and

the imprecisions inherent in these measurements may introduce inequities in trade as

well as inhibit expansion of the technology.

A need, therefore, is shown for acoustical

research directed toward: the basic physical

phenomena; the study and evolution of improved measurement facilities and instruments

(tools); and the improvement of the required

measurement methodologies (the use of the

tools).

Continued study of the National Measurement System for Acoustics will facilitate

improved communication between the various

participants to enable adaptations of the

system to meet changing needs.

42
NBSIR 75-939

THE NATIONAL MEASUREMENT SYSTEM FOR RADIOMETRY AND PHOTOMETRY

Henry J. Kostkowski

NBS Optical Physics Division

April 1975

EXECUTIVE SUMMARY

This National Measurement System Study is on the measurement of light. More specifically it is concerned with the measurement

of the energy or power in ultraviolet, visible and infrared radiation.

The study was undertaken to determine the

importance of such measurements in the U.S.,

the accuracy and ease with which they could

be made, the adequacy of this capability,

and finally, the nature of the program NBS

should pursue in this measurement area.

In the last ten years, the economic and

social impact of radiometric and photometric

measurements has increased significantly.

Such measurements are required in the manufacture of cameras, color TV and copying

machines. Ultraviolet radiation is being

used extensively for the polymerization of

industrial coatings. An attempt is being

made to use radiometry in measuring atmospheric temperatures for the purpose of

forecasting weather. New solid-state lamps

(LEDs) are used in a variety of visual

displays. Phototherapy is used almost ex- clusively in the treatment of some diseases

(e.g. jaundice in the newborn). Regulatory

agencies are concerned with the hazardous

effects of UV on the eyes and skin (skin

cancer), particularly in industrial environments. Dentists are now using a com- mercially available "UV gun" for curing

various new dental materials. Applications

in the lamp industry are increasing because

of our energy problems. Twenty-five percent

of the U.S. electrical power is used for

lighting, and thus, developing lamps that

will produce the same light for less electrical power has a high priority. Developing the utilization of solar energy will

require better measurements than are now

available. All of these uses and applications of light require radiometry or photometry. Many of them will require a state-ofthe-art accuracy of 1% in order to achieve

their objectives.

Unfortunately, the current radiometric

and photometric measurement system is inadequate for the many uses and applications

described. Radiometric measurements are among the most difficult measurements to make. The radiant power varies with position, direction, wavelength, polarization

and time, and the responsivity of most radiometers also varies with these and other

parameters, making such measurements a difficult, multi-dimensional problem. In addition,

most of the people wanting to use radiometry

have not been trained in the field. There

are relatively few experts available. As a result of these two factors, measurement

accuracy is poor and large differences in

measurement are widespread. Much time and

money is spent trying to resolve these differences, particularly when mass produced

products require components from various

companies and these components must meet

radiometric or photometric specifications.

The cost of inadequate radiometry and

photometry is very high. The electro-optical

industry alone has annual sales approaching

15 billion dollars per year. A leading

instrument manufacturer estimates that about

$200 million is spent each year in calibrating radiometric systems or resolving

discrepancies in radiometric measurements.

If better radiometry can improve long-term

weather forecasting as predicted, the economic

impact would be tremendous. It is virtually

impossible to estimate the cost of inadequate

radiometry relative to medical and safety

applications, but public health and safety

are certainly given a high priority in this

country.

Adequate radiometry today means making 1%

measurements commonplace. This will require

greater expertise in the system and more

accurate, easy-to-use, and less expensive

standards and techniques.

NBS has addressed itself to solving these

problems. It helped organize the Council for

Optical Radiation Measurement (CORM), a group

largely representing industry and providing

detailed information and a consensus of the

needs in the system. It has worked with the

Illuminating Engineering Society (lES), the

Commission Internationale de L'fclairage (CIE),

and the Infrared Information Symposia (IRIS).

NBS is developing more accurate, easy-to-use,

less expensive standards and techniques and

is beginning to monitor the capability of the

system by interl aboratory comparisons. It has created specialized publications to insure that all this information is efficiently disseminated. Finally, NBS is also

starting to produce a Self-Study Manual for

Optical Radiation Measurements. This is expected to significantly upgrade the level

of expertise in the U.S. in this area.

43
In summary, this study has shown that

radiometry and photometry are having a significant economic and social impact in the

U.S. today and this impact is expected to increase. The capability of this portion

of the measurement system is inadequate for

today's needs. One percent measurement is frequently needed; 10-50 percent is commonplace. The reason is that radiometric and

photometric measurements are very difficult

to make, and there is too little expertise

to make these difficult measurements. NBS' program is designed to improve the situation

by (1) making the measurements easier through

simpler, inexpensive standards and techniques and (2) increasing the expertise

through a Self-Study Manual on the subject.

44
NBSIR 75-940

THE NATIONAL MEASUREMENT SYSTEM FOR SPECTROPHOTOMETRY

William H. Venable, Jr. NBS Optical Physics Division

April 1975

EXECUTIVE SUMMARY

This microstudy covers the field of spectrophotometry and the work in this field

being conducted in the Optical Radiation

Section at NBS. In general, spectrophotometry provides an answer to such questions as how much light is reflected by an object or transmitted through it. ("Light" is used

here in a very general sense which includes

the light we see and other electromagnetic

radiation in the adjacent portions of the

spectrum which behaves in a manner similar

to light.) The technological significance

of spectrophotometric measurements lies in its use as a tool for determining something

about the object. Combined with a knowledge

of the way the human eye functions, spectrophotometry can be used to predict and control the way an object will appear. Thus

spectrophotometry can become the "eyes" for

the automated production and quality control

in the manufacture of objects and materials

in which appearance is important. Taken

with knowledge of the optical properties of

chemicals, spectrophotometric data forms a basis for quantitative chemical analysis in

a huge variety of fields from clinical

testing to manufacturing. There are countless other applications in such areas as photography, remote sensing, warning devices

for safety, and nondestructive inspection of

agricultural products.

As the foregoing indicates, the user com- munity is huge. The processes in which

spectrophotometric measurements are or could

be significant are estimated to account for

about one-fourth of the gross national product. It should be pointed out, that in most

cases, the spectrophotometric measurement is only a small part of the total operation for

a given user. As a result, the spectrophotometric measurement community for the most

part is made up of a huge number of widely

diverse individuals who use spectrophotometry as a tool and who do not have a strong

knowledge of the field. They rely on the

instructions which come with their instruments and on standard test procedures. This

large, highly diverse community is the productive level of the spectrophotometric com- munity.

At the next level above the user community lies practically all of the rest of

this measurement system. The instrument

manufacturers, the military, government, and

commercial measurement laboratories, and the

many committees which develop and publish

the standard measurement techniques interact

directly or nearly directly with the user community. The standards and services supplied by this second level are adequate for some applications, but if the full value of

spectrophotometry is to be realized, the error in these measurements must be reduced

by a factor of ten. With a reduction of error by this magnitude, one would just pass

a very practical set of limits in the need

for accuracy. These limits result from limits in the ability of the human eye to distinguish differences in appearance, limits

in the ability or need to control production

processes and limits in the precision with

which samples can be prepared for analysis.

The measurements must reach these limits in

order to provide the basis for an orderly

market place in which measurement errors

have small economic or other practical con- sequences, and in order to allow full utilization of spectrophotometric analysis.

Since there must be allowances for lag in feedback loops, these limits must be slightly exceeded in order to fully utilize spectrophotometric sensors in automated control

of production.

In order to bring about such an improvement in the measurement system, a strong capability for highly accurate mea- surement must be built up. The instrumentation and labor required for this effort

would be too much for any one of the instrument manufacturers of commercial laboratories to handle, much less for any individual user. To be economical, this capability should be in a central laboratory,

and, in the interest of fairness, this laboratory should be on "neutral ground".

Quite obviously, NBS is the laboratory for

such universal standardization of these

measurements to take place. From the mid

1950's until very recently, the spectrophotometry program at NBS was small and

geared principally to measurements as a service to the rest of NBS and to other

government agencies. However, during the

past two years, the spectrophotometry program at NBS has been revised and our meas- urement capability is being built up to the

45
point where we can supply the leadership

required for increasing the accuracy and

extending the range of spectrophotometric

measurements.

Through our study, we have clearly recognized the magnitude of the user community

and the potential advantages which can come

from an order of magnitude improvement in

the measurements. We have gained an insight into what needs to be done by NBS in this respect and have initiated a program

through which we can do our part. The new

NBS capability should be fully developed

during the next five years, at which time

the full impact of our efforts will begin

to be felt. Although we will maintain contact with individual users of the measurements in order to obtain a measure of the

effectiveness of our program, our main

point of contact will be with instrument

manufacturers and secondary standards laboratories. Through measurement assurance

programs and other assistance to these

groups, we feel we can amplify our efforts

most effectively to bring about the needed

improvements in the measurement system. We

will also be providing several very general

standards through the Office of Standard

Reference Materials.

The potential benefits which can be obtained from improving spectrophotometric

measurements is estimated to be as great

as two billion dollars annually, principally in increased productivity through

automation. It is our intent to provide

leadership which will enable to the scientific, technical, and industrial community to obtain those benefits as readily

as possible.

46
NBSIR 75-941 THE NATIONAL MEASUREMENT SYSTEM FOR FAR ULTRAVIOLET RADIOMETRY

William R. Ott

NBS Institute for Basic Standards

August 1975

EXECUTIVE SUMMARY

Radiometry is the quantitative measurement of radiant power. By restricting the

region of interest to the far ultraviolet,

the wavelength region from about 10 nm to 300 nm is specified. The corresponding

photon energy range extends from 125 eV to

4 eV, very large compared for example with

the visible range which extends only from

3 eV to about 1.8 eV. Because of this, a wide variety of phenomena and radiometric

applications can be found throughout the

far ultraviolet. This report is a description of the evolving National Measurement System in the field of Far Ultraviolet

Radiometry; at the same time a critical

evaluation of the NBS role in the System is

made in order that we might optimize our efforts toward serving the System and thus

promote progress toward the national goals

of our government.

The technological importance of the far

ultraviolet spectral region stems essen- tially from: (a) the increasing use of high

temperature devices such as the fusion

plasmas being produced in the search for new energy sources; (b) the industrial

potential of far ultraviolet and x-ray

lasers; (c) the high energy content of

short wavelength radiation with the con- sequent ability to drive and control chemical reactions; and (d) the very low diffraction limit of short wavelength radiation. The problem areas where ultraviolet

radiation measurements are important include both national research and development programs and major industrial applications in the following fields:

(1 ) Industrial Photochemistry

(2) Bacteriological Control

(3) Environmental Studies

(4) Medical Therapy

(5) Fusion Research

(6) Space Science

(7) Ultraviolet and X-Ray Lasers

(8) Plasma Chemistry

(9) Photobiology

In order to evaluate whether or not an ultraviolet radiation measurement capability is in the national interest and

affects our well being and the common good.

both the social and economic significance

of those activities which depend upon such

a capability are discussed. Examples of areas of impact where the ultraviolet

measurement system enjoys considerable

social and economic leverage are national

health and safety and solar simulation.

Numerous studies which are cited in this

microstudy indicate that ultraviolet radiation can be dangerous and can cause such

things as incapacitating burns (sunlamps

and arc welders are the biggest culprits),

premature wrinkling, and skin cancer. In view of the increasing use of ultraviolet

lamps in our society for illumination,

advertising, bacteriological control,

medical treatments and industrial polymerization applications, and in view of our recent concern with the disastrous con- sequences which would result from even a small increase in solar ultraviolet transmission through out atmosphere, a measurement capability is absolutely necessary.

It is used not only to monitor the light

environment and thus guarantee radiation

safety but also to enable definitive ex- periments which will accurately specify the

safety limits themselves. If the social

benefit is obvious, the economic leverage

is no less so. Our work force is weakened

considerably not only by work-related

radiation accidents involving arc welders,

high intensity sterilization lamps, etc.,

but also by the common weekend-in-thegarden sunburn. Outdoor workers are especially affected and experience in addition

a significantly high incidence of skin cancer. The statistics are available and

one can easily estimate the economic impact

of thousands of careers terminated in this

way.Accelerated weathering machines and

solar simulators are used by the paint,

dye, plastics, and building material industries as well as for space-related

applications, for example, in determining

the lifetime of solar cell arrays. Correlations up to now have not always been

significant partly because the irradiance

is specified by time exposed and not in terms of intensity and spectral distribution. Because of the uncertainties in the
lamp characteristics, not only are large

amounts of money and effort wasted annually

in the collection of misinformation and in some cases by the production and distribution of inferior products, but also the

industries are discouraged from increasing

their efforts toward developing superior

weather-resistant products. Ultraviolet

calibrations of these machines for wavelengths as low as 121.6 nm are required if

accuracy, consistency, and cost effectiveness are to be achieved in testing. Manufacturers of the simulators are equally

concerned with improved diagnostic methods

since their world market could be threatened by the imposition of radiometric

specifications on the machines by international standardizing bodies.

The NBS program on far ultraviolet

radiometric calibrations is carried out in

the Plasma Spectroscopy Section (232.07)

and in the Far UV Physics Section (232.03).

It consists of several complementary com- ponents and makes use of absolute detectors

as well as standard radiation sources. The primary consumers of our vacuum ultraviolet services have been the space scientists who need absolute detectors and sources to determine the response of

spectrometric optical systems. At present

these users dominate by about 10:1 over

the combined number of all other consumers.

This statistic is due mainly to the chronology of how the National Measurement

System has evolved: research and scientific explorations (NASA in the 60' s)

force the development of advanced technology which, in turn, stimulates and makes

possible new applications of that technology.

There is substantial evidence that we are entering this latter productive and potentially explosive stage. Nevertheless, it is

shown in this report that there is little

systematic interaction between the standards

community and the users groups. Aware of

this evolution and the changing priorities,

NBS cannot only be open and receptive as it

has always been, but must actively develop

new contacts. It is recommended that NBS

initiate more mini-workshops similar to the

successful meetings involving several regulatory agencies, which we organized during

1972-1974. Photochemical and biomedical

applications should be the first areas where

NBS should generate such a new initiative.

There are several technical recommendations in this report which are the result

of some preliminary contacts of the type

just discussed.

(1) NBS, although boasting two complementary programs toward the development of

primary, far ultraviolet radiometric source standards, currently supports no efforts to develop reliable transfer standards. This

situation must be rectified in view of

requirements for field uncertainties of

about 1 percent between 200 nm and 300 nm,

5 percent between 90 nm and 200 nm, and 10

percent below 90 nm.

(2) We must plan to develop ultraviolet

source standards of spectral irradiance,

the unit of principal interest to the users. Unless this is done, we must leave

it up to the individual users to generate

their own irradiance standards by way of our spectral radiance standards. Not only

is this an expensive and counter-productive

way to go, but also it makes for a very

uncertain traceability to NBS.

(3) NBS standard detectors, although

fairly well developed, should be modified

and improved so that they are usable by

several high priority users who have applications requiring pulsed operation and/or

high intensities.

(4) Internal consistency among the

various NBS radiometric standards must be

systematically checked. This includes such

independent standards as photodiode detectors, synchrotron radiation, hydrogen arc radiation, electrically calibrated radiometers, and tungsten lamps.

48
NBSIR 75-942

THE NATIONAL MEASUREMENT SYSTEM FOR OPTICS

Denms A. Swyt

NBS Optical Physics Division

August 1975

EXECUTIVE SUMMARY

Measurements in imaging optics are fundamental to manufacture of products ranging from

spectacles, microscopes, photographic goods

and microfilmed documents to aircraft, nuclear

reactors and oil pipelines; measurement quantities of interest are "diffuse visual density" which characterizes the darkness of photographic, radiographic and ink-on-paper images;

and numerous measures of optical system performance (refractive power, resolution, optical transfer functions, etc.). Diffuse visual

density is defined by ANSI documentary standards; many voluntary standards and federal

specifications relate to its application.

These measurement are most intimately re- lated to the photographic and optical industries. In figures characteristic of the early

1970' s, their outputs included $1.3 billion

worth of sensitized photographic goods, $4

billion in photographic products and $485

million in lenses and optical instruments.

$5 million of densitometers and $35 million

in non-opthal mi c test equipment provided some

of the means of measurement.

Some of the measurements are performed by:

*18,000 eye examiners and 20,000 dispensers

of lenses supplying 100 million wearers of

corrective lenses with opthalmic lenses

costing $190 million in a $2 billion system of eye care. *10,000 medical radiologists, supported by

90,000 technicians, examining 325 million

x-rays of 110 million patients at a cost

of $4 billion.

*15,000 industrial radiographers performing

45-90 million measurements in over 6300

plants at a cost of $350 million. Typical

data for products affected by these mea- surements are $7.6 billion in aircraft,

$4.6 billion in missiles and space hard- ware, $64 billion in nuclear reactors con- tracted for in the period 1965-73, and

$600 million of pipelines constructed

annual ly

.

NBS provides diffuse visual density standards, microcopy resolution charts and an optical system and lens evaluation service.

The density standards are used by, among others, the eleven companies which accounted for

virtually 100% of photo film sales and 80% of

equipment sales in 1970; the standards are required by AEC, NASA, DOD, FAA, and DOT

specifications. The NBS Microcopy Resolution

Chart is a voluntary standard for the $450

million microfilm industry and a mandatory

standard for use in DOD microfilming opera49

tions; the NBS chart is on the verge of formal acceptance as an international standard.

The lens testing services have primarily

benefited federal agencies.

In eighteen month periods in which outputs

of NBS were evaluated, a program which in 1973

consisted of 3 1/2 man-years of effort with a $319,000 budget (of which $118,000 was from

other federal agencies) provided 15,000 microcopy charts, 200 density standards, 10 interferometers for an AEC prime contractor, a handful of lens tests, a number of special studies

for federal agencies, a significant amount of

testing and consultation on optical systems

for security-classified federal agencies, as well as major publications on the theory and

operation of advanced optical systems.

The primary effect of this study has been

to reveal the nature of the users of NBS ser- vices and the degree of their dependency on the standards NBS supplies. Incremental analysis, the tracing of the economic effect of

NBS services through causal chains to final

products and services, has not proven feasible. Isolated examples of the cost benefit

to users of their own measurements are given;

e.g., the cost of a "traceable-to-NBS" radiograph may be $10: the part under inspection

may be a flange for a nuclear reactor; economic loss to the reactor owner in down-time

and repair work due to a flange failure:

possibly $250,000.

Recommendations regarding NBS programs are

to upgrade density measurement capabilities,

to maintain without further expansionary

investment the lens testing services, and to channel image analysis measurements toward

optics-related measurement problems. Discontinuation of NBS services in this field,

it is thought, would result in the provision

of the same services by one or more other

federal agencies. Continuation of the study

of the measurement system might involve

assessments of the desireability of NBS ref- erence standards of reflection density and of

the interest of optical manufacturers in a round-robin approach to measurement assurance

in lens testing.

Documentary data and informed opinion for

this study have been acquired by means of a survey questionnaire to 150 users of calibration services; canvassing letters to 30 instrument manufacturers, 25 trade and industrial

associations, and 50 optical companies; personal interviews with 30 individuals at organizations throughout the country; innumerable

telephone contacts; as well as direct use of

documentary and library source materials.

NBSIR 75-944

THE NATIONAL MEASUREMENT SYSTEM

FOR THE PHYSICAL PROPERTIES OF ATOMS AND MOLECULES

J. W. Cooper, A. V. Phelps and S. J. Smith

Institute for Basic Standards

August 1975

EXECUTIVE SUMMARY

The national activity in the measurement,

compilation, evaluation, and dissemination

of atomic and molecular data is represented

here as a component of the national measurement system. The significance and validity

of this representation rests largely on the

role of the National Bureau of Standards in

the development of measurement techniques,

the encouragement of standards of measurement performance and in efforts to generate

an adequate and wel 1 -documented data base

effectively constructed to meet the needs of

the user community.

The level of national activity in this

field is estimated to be in the range of

20-25 million dollars annually, and the

NBS programs in atomic and molecular mea- surements and in data evaluation and dissemination are approximately 3 million dollars

of the total. The output of this activity

has a direct impact upon applied research

and development projects currently funded

at a level well in excess of a third of a billion dollars annually. The largest of

these are ERDA-supported programs aimed at energy generation and conversion (conventional controlled thermonuclear research,

laser fusion, laser isotope separation,

coal -burning magnetohydrodynami c generators,

etc). There are large potential benefits

for a broad range of industrial research

and development activities. Atomic and

molecular measurements are also extremely

important to basic research in astrophysics,

atmospheric physics, plasma physics and

aerodynami cs

.

Examples of recent and current contributions with large impact range from data on specific single processes which play a determining role in some development problems, such as the control of ion propulsion

engines for NASA, to entire data sets with

which the behavior of a laser plasma or an MHD generator may be programmed and studied

with electronic computers. The maturing

of this kind of computational capability

is of the greatest significance for the

advancement of the technology of plasma

devices. This significance is well recognized by the atomic and molecular community

which sees it as the vehicle for meaningful

contributions toward solution of urgent

economic and social problems. It is

increasingly recognized within ERDA energy

source development programs as an essential

tool for orderly progress in their projects.

It is generally less widely recognized in

the industrial development community.

Certain atomic and molecular properties

are used at the limits of achievable accuracy as the basis of the accepted standards

for length, time and frequency. An atomic

standard for mass is foreseen. Precision

measurement techniques developed by workers

in the field of atomic and molecular physics

have been incorporated in the development of

standards for measurements of other quantities, for example, gas pressure and radiant

flux.

It is recommended that the National

Bureau of Standards undertake activities

which involve direct participation and

interaction with the major governmental en- ergy development projects, that it use this

experience to guide development of new mea- surement methodology in atomic and molecular

physics, and that it undertake to ensure the

reliability and adequacy of the data base

needed for these projects. Furthermore, it

is recommended that the NBS expand its con- tacts with private industry, develop increased

awareness of the methodology for applying

atomic and molecular data to technological

development, and provide such advice and

guidance as will assure the effective utilization of this sector of the measurement

system for the benefit of the economy.

51

NBSIR 75-945 THE NATIONAL MEASUREMENT SYSTEM FOR SURFACE PROPERTIES

C. J. Powell

NBS Optical Physics Division

May 1975

EXECUTIVE SUMMARY

There is a large number of solid-surface

properties that can be measured and these

have been arbitrarily divided into two classes. First, there are the properties

which can be used to characterize a surface:

surface composition (as a function of

position), surface atomic structure, surface

electronic structure, the nature and distribution of surface defects, surface topography, and the nature and area of exposed

facets. Second, there are derived properties of the surface characteristics as just

defined and measures of the processes that occur on surfaces: electrical properties,

optical properties, adhesion, bonding,

catalytic activity, plating, durability,

corrosion, decoration, grain-boundary segregation, lubrication, and reactivity. This

report discusses directly only those mea- surements that are used for surface characterization with particular emphasis being

given to the most common measurement, the

measurement of surface composition, and

lesser emphasis to the measurement of surface

atomic structure and surface electronic

structure. Measurement of surface topography

is discussed in a separate report of this

series by R. D. Young.

Throughout the report, the term "surface"

is defined as the "outermost" layer of atoms

of a solid. Thus, consideration is given

primarily to those properties (and measurement methods) which are specific to the

surface as defined. Some consideration is

given also to the measurement of composition

as a function of depth from a surface and at solid-solid interfaces.

A dramatic feature of this part of the

National Measurement System is the rapid

growth of surface science and surface technology and the substantial accomplishments

that have been made in the past ten years.

Surface science and surface technology are widely regarded as "frontier" areas in which

major scientific breakthroughs and major improvements in materials and processes will occur. Most of the measurement methods now in use for surface characterization have become

commercially available within the past ten years. At this time there is a complete

lack of standards, standard procedures, and

standard materials to support surfacecharacterization measurements. In short,

there is no established measurement system

for the measurement of surface properties.

Most measurements of surface composition

are now performed by Auger-electron spectroscopy and, to a lesser extent, by x-ray

photoel ectron spectroscopy, ion-scattering

spectroscopy and secondary-ion mass spectroscopy. The sales of these instruments

have been estimated to be about $10M per

year with a current growth rate of 20 to 30%

per year. About 60% of these instruments

are in use in industrial laboratories, 20%

in Federal Government laboratories, and 20%

in university laboratories.

The surface-characterization measurements

made in university and some other laboratories are frequently made to develop a fundamental understanding of the properties of

relatively ideal (i.e., single-crystal)

surfaces and of processes that occur on them. Surface-characterization measurements

made in government laboratories support a variety of agency missions, ranging from

national defense, space, energy, to the

environment.

Measurements of surface composition are routinely made to solve an extremely wide

range of industrial problems (of which

examples are given). Most of these measurements are made in the semiconductor, chemical, petroleum, and metallurgical industries

for applications ranging from process and

device development, process control, process

evaluation to failure analysis. The economic benefits were difficult to estimate but

are believed to be substantially greater

than the corresponding costs. Continued growth in surface science and

surface technology (and in the required

surface-measurement capability) is predicted

for the foreseeable future (the next five

years). Present national goals for solution

of the energy crisis, provision of an adequate defense capability, control of environmental pollution, increase of industrial

productivity, and the development of advanced

materials for improved individual health and

safety and for the automobile and aircraft

industries will require use of surface

technology and improved surface-characterization measurements. Other factors which

will stimulate growth in surface-measurement

capability are projected developments in surface science, development of improved
instrumentation, development of quantitative

methods for surface characterization, legal

needs, and anticipated growth in the applications of surface analysis.

Present surface-characterization mea- surements make use of reference data generated by instrument manufacturers, universities, government and industrial laboratories, and by NBS. Many important measurement needs have been identified, the most

important (for surface technology) being to provide data and procedures to quantify

measurements of surface composition. It is

anticipated that the development of standards, standard procedures, reference data,

and standard materials will be coordinated

through the recently formed ASTM Subcommittee

E2.02 on Surface Analysis.

Other measurement needs in surface science

and surface technology have been identified.

Many surface properties and processes depend

on the surface composition, atomic structure,

and particularly the surface electronic

structure. It is anticipated that future

developments in surface science will lead to

a more detailed understanding of the mechanisms of catalysis, corrosion, adhesion,

lubrication, and wear so that new materials

with improved properties can be designed.

Advances of this type depend on the development and application of new measurement

methods to characterize disordered surfaces,

highly dispersed catalysts, transient species

on surfaces, the kinetics of reacting species, and the properties of such surfaces in

their working environments.

NBS programs in surface physics have had

considerable impact on the development of

surface science through the development of new instruments and measurement methods, the

observation of new surface properties, the

development of new theories and concepts,

the provision of reference data, and the

publication of data compilations and critical

reviews. NBS data is also being used in

surface technology. Additional NBS effort

is required, however, to promote surface

technology.

Twelve recommendations are given for NBS

action to improve and extend the measurement

services required for the support of surface

science and surface technology. Meaningful

action by NBS and other interested groups

should enable the establishment of a satisfactory National Measurement System for the

Measurement of Surface Properties in the

future.

54
NBSIR 75-946

THE NATIONAL MEASUREMENT SYSTEM FOR IONIZING RADIATION

Randall S. NBS Center for Ra March

EXECUTIVE SUMMARY

The structure of the National Measurement

System for Ionizing Radiation has been investigated for eight prime classes of radiation users: medical, nuclear power, industrial radiation processing, defense, environmental, science, chemical analysis, and

miscellaneous radiation applications, plus

two "overlay" categories, regulatory control

of radiation and personnel monitoring. Needed major actions on the part of NBS were

identified for nuclear power and its related

environmental and safety impacts, medical

applications of radiation, assistance to regulatory control of radiation and measurement assurance for personnel monitoring..

The regulatory control of radiation is

divided among ERDA, the Nuclear Regulatory

Commission, the EPA, the Bureau of Radiological Health, the Occupational Safety and

Health Administration, the National Institute

of Occupational Safety and Health, and the

Department of Transportation. Forty-six

states and Puerto Rico have passed radiation

control legislation. Radiation regulation is normally administered by state health departments which vary widely in support, staff,

and technical competence. They work to- gether through the Conference of Radiation

Control Program Directors. Needs defined

are: (1) all regulators of radiation need

to be on the same measurement scale; and

(2) the great majority of state health

departments would be benefited by a program

of technical assistance in radiation and

measurement. NBS has (1) instituted a program of measurement assurance testing to establish traceability with lead laboratories

of ERDA, EPA, and other regulatory agencies,

and (2) proposed a National Radiation Measurement Calibration System for the benefit of

the states, regional calibration laboratories, and regulatory agencies.

About 800,000 persons considered radiation

workers wear personnel monitors. Most such

monitoring is supplied by fewer than 20 com- mercial suppliers, although government

laboratories and the military services

largely provide their own service. Two needs

are apparent: (1) a high-quality measurement

assurance testing laboratory to test monitoring services, and (2) monoenergetic neutron

calibration fields to test and develop neu- tron personnel monitors. NBS actions in response to (1) are under active discussion

with the states and other Federal Government

Caswel

1

diation Research

1975

agencies. NBS is now developing a radiation

calibration facility for neutron personnel

monitoring with ERDA support.

Four medical radiation user groups have

been identified: radiation therapy, diagnostic x-rays, dental x-rays, and nuclear medicine. About 350,000 patients are treated

with radiation therapy per year, representing

50-60% of cancer cases. In 1970, 129 million

persons received 210 million diagnostic x-ray

examinations. In 1971 there were more than

105,000 diagnostic x-ray machines and 117,000

dental x-ray machines. In 1971 there were

eight million applications of radiopharmaceuticals given for diagnosis. One patient

in four entering the hospital will be administered radioisotopes for diagnostic test(s).

Measurement needs apparent include: (1)

wider dissemination of NBS dosimetry calibrations; (2) development of primary absorbed

dose standards for high-energy (linac and

betatron) x-rays and for fast neutron radiotherapy; (3) extension of a system of quality

control throughout the approximately 8,000

institutions doing nuclear medicine; (4)

straightening our of problems with radionuclide dose calibrators. In each case NBS

actions are underway or being developed with

others to meet these needs.

The study of nuclear power is concerned

with: nuclear fuel cycle operations, and

design data and reactor operations. A special study by John W. Bartlett, Assessment of the Nuclear Fuel Materials Measurement System , found that the need for ac- curate accountability of fissionable materials stems not from buyer-seller equity but

rather from the need to safeguard nuclear

material. It seems certain that there will

be a need for NBS participation in and technical assistance for a major measurement as- surance system for nuclear fuel materials

accountability, and discussions on this

subject are underway between NBS and the

Nuclear Regulatory Commission. At present,

NBS programs are responding to needs for new Standard Reference Materials, improvement of

the technical base for calorimetry, collaboration with the ERDA New Brunswick Laboratory

in support of the measurement assurance ac- tivities of the Safeguards Analytical Laboratory Evaluation (SALE) program, and analysis

of materials diversion paths and data requirements.

In the area of design data and reactor

operations , needs are for standards for neu- tron cross section measurement in support of
LMFBR (liquid metal fast breeder reactor),

HT6R (high temperature gas-cooled reactor),

and thermal neutron power reactor programs;

and for measurement standards for in-reactor

measurements of neutron flux and spectra and

fission rates in fuel elements. For fission

reactors improved cross sections are needed

for shielding, fuels, neutronics of structural materials, integrity of reactor com- ponents, and reactor control and safety. For fusion reactors, nuclear cross section data

needs are less immediate; but data will be

needed for shielding, heat transfer element

design, tritium breeding design, integrity

of structural materials, and induced radioactivity problems. Standards for in-reactor

measurements of neutron flux and spectra and

fuel element fission rates are important in

testing reactor performance versus calculations, testing of fuel, temperatures of fuel,

reactor lifetimes, power level, control, and

safety. A neutron standards program in NBS

aimed at greatly improving the accuracy of

standard reference neutron cross sections,

and neutron fluxes used to measure other

cross sections, and providing standard ref- erence neutron fields for the basis of inreactor neutron measurements is now at full

strength using the NBS linac. Van de Graaff,

and reactor.

The field of industrial radiation processing continues to grow, although more slowly

than indicated by some earlier predictions.

The energy crisis may, in fact, speed development in this area since radiation processing uses less energy than do corresponding

thermal processes. NBS offers calibration

services for the megarad disometry range on

a limited basis. Establishing measurement

service requirements is somewhat hindered by

the proprietary nature of this field and the

high degree of industrial secrecy. Some new needed calibration services are being developed, but no needs for major new programs

have been identified.

The study of radiation measurement for

national defense has identified needs in the area of high-intensity, pulse x and gamma

radiation measurement. The NBS action in

response has been development of new ordersof-magnitude more intense calibration sources. Defense Department needs in the measurement

of radioactivity appear to have been met by

NBS programs for development of radioactivity

standards, particularly for the noble gases.

The study of environmental radiation meas- urement identified a need for environmental

radioactivity standards and for environmental

radioactivity measurement assurance testing.

NBS has recently developed a new series of

mixed radionuclide environmental radioactivity standards which are now available to the

environmental measurement community, and

many measurement assurance tests are being

carried out to help members of the community

and lead laboratories of ERDA and EPA test

and improve their measurement performance.

State laboratories receive NBS-traceable

standards from and participate in measure- ment assurance testing with the ERDA and EPA measurement laboratories.

In the areas of science and chemical

analysis , existing programs in support of

these fields need to be continued. For

science, a data compilation effort on charged-particle stopping powers, ranges,

straggling and delta-ray production below

about 10 MeV is needed.

Miscellaneous radiation applications include radiographic equipment, gauges, irradiators, oil-well logging apparatus, selfluminous products, smoke detectors, static

eliminators, and heat sources. The annual

business in these devices is in excess of

70 million dollars. The most stringent re- quirements for accurate measurement appear

to be at the manufacturing level. A chief

problem is the need for adequate safety measures in the use of this equipment. This

problem is being attacked through vigorous

NBS participation in voluntary standards

committees such as American National Standards Institute (ANSI) Committee N43 which is

concerned with promulgating recommendations

for safe use of radiation equipment.

A number of common threads stand out quite

strikingly in the studies of the various

users of radiation: (1) There is often a need for new NBS measurement standards where

they do not exist--however, where NBS meas- urement standards do exist their accuracy

is generally sufficient for present needs.

(2) There is a great need for measurement

assurance, especially where regulatory re- quirements are involved. Usually priorities

found in this study are much higher for dissemination of standards to users and carrying

out measurement assurance testing than for

development of new measurement standards.

(3) A need exists for help to the poorlyqualified user--training, convenient laboratory standards, handbooks for guidance.

(4) A single measurement system under NBS

leadership is needed to help both regulators

and users, to avoid duplication and competition among regulators, to simplify the radiation users' problems of measurement and re- porting, and to protect the health and safety

of the public. (5) Needs for NBS to play

its traditional "independent third party"

role are often found.
NBS.114A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. 2. Gov't Accession

NBSIR 75-947

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Collected Executive Summaries

Studies of the National Measurement System

1972-75

5. Publication Date August 1976

6. Performing Organization Code

270.00

7. AUTHOR(S)

Raymond C. Sangster, Editor

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 2700916

11• ( nntr^if^f/ (ir ant Wi-* L)l 1 L I L / vJidlll INC.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

National Bureau of Standards, Institute for Basic Standards

Office of the Deputy Director, IBS/Boulder

325 Broadway

Boulder, Colorado 80302

13. Type of Report & Period Covered

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

This report contains the Executive Summaries of the reports of the 1972-75 study by thje

NBS Institute for Basic Standards of the U.S. National Measurement System, which consists of all of the activities and mechanisms which provide physical measurement

data required by our society. A series of microstudies focused on specific technical

measurement sectors. A macroeconomic study looked at costs of instrumentation and

labor for measurement- related activity in our economy. University economists were

retained to assist the microstudy authors and to prepare an overall economics report.

A central coordinator set a basic pattern for the microstudies, prepared an overall

summary report, and generated several documents relating to the system as a whole.

Abbreviated titles of the executive summaries are: Final summary report. Direct

measurements transactions matrices. Economic analysis. Structure and functions of

measurement system. Time and frequency. Length and related dimensional measurements;

vibration and shock. Surface finish. Mass, volume and density. Force. Fluid flow

Pressure. Temperature. Humidity and moisture. Thermodynamic properties of fluids.

Cryogenics. Electricity. Electromagnetics. Medical ultrasonics. Acoustics.

Radiometry and photometry. Spectrophotometry. Far ultraviolet radiometry. Optics.

Physical properties of atoms and molecules. Surface properties. Ionizing radiation

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Acoustics; atomic properties; economics; electrical quantities; ionizing radiation;

mechanical quantities; national measurement system; optical quantities; surface

properties; thermal quantities; time and frequency.

18. AVAILABILITY IXX Unlimited

I For Official Distribution. Do Not Release to NTIS

I

' Order From Sup. of Doc, U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. Cl^

ly^

^ Order From National Technical Information Service (NTIS)

Springfield, Virginia 2215L

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

53

22. Price

$4.50

USCOMM ERL USCOMM-DC 29042-P74

REQUEST CARD FOR REPORTS OF NATIONAL MEASUREMENT SYSTEM (NMS) STUDY ( Circle No's wanted )

925 FINAL SUMMARY REPORT 929 FORCE

943 TRANSACTIONS IN NMS

947 COLL. EXEC. SUMMARIES

948 ECONOMIC ANALYSIS NMS

930 FLUID FLOW

931 PRESSURE

932 TEMPERATURE

949 STRUCTURE/FUNCTIONS NMS 933 HUMIDITY & MOISTURE

345-1 TIME & FREQUENCY

926 LENGTH & DIMEN. MEAS.

;

VIBRATION & SHOCK

927 SURFACE FINISH

928 MASS, VOLUME, DENSITY

934 THERMODYNAMICS OF FLUIDS

825 CRYOGENICS

935 ELECTRICITY

936 ELECTROMAGNETICS

REQUEST CARD FOR REPORTS OF NATIONAL MEASUREMENT SYSTEM (NMS)

925 FINAL SUMMARY REPORT 929 FORCE

943 TRANSACTIONS IN NMS

947 COLL. EXEC. SUMMARIES

948 ECONOMIC ANALYSIS NMS

949 STRUCTURE/FUNCTIONS NMS

345-1 TIME & FREQUENCY

926 LENGTH & DIMEN. MEAS.

;

VIBRATION & SHOCK

927 SURFACE FINISH

928 MASS, VOLUME, DENSITY

930 FLUID FLOW

931 PRESSURE

932 TEMPERATURE

933 HUMIDITY & MOISTURE

934 THERMODYNAMICS OF FLUIDS

825 CRYOGENICS

935 ELECTRICITY

936 ELECTROMAGNETICS

REQUEST CARD FOR REPORTS OF NATIONAL MEASUREMENT SYSTEM (NMS)

925 FINAL SUMMARY REPORT 929 FORCE

943 TRANSACTIONS IN NMS

947 COLL. EXEC. SUMMARIES

948 ECONOMIC ANALYSIS NMS

949 STRUCTURE/FUNCTIONS NMS

345-1 TIME & FREQUENCY

926 LENGTH & DIMEN. MEAS.;

VIBRATION & SHOCK

927 SURFACE FINISH

928 MASS, VOLUME, DENSITY

930 FLUID FLOW

931 PRESSURE

932 TEMPERATURE

933 HUMIDITY & MOISTURE

934 THERMODYNAMICS

825 CRYOGENICS

935 ELECTRICITY

936 ELECTROMAGNETICS

937 MEDICAL ULTRASONICS

938 ACOUSTICS

939 RADIOMETRY/PHOTOMETRY

940 SPECTROPHOTOMETRY

941 FAR UV RADIOMETRY

942 OPTICS

944 PHYS. PROP. ATOMS/MOL.

945 SURFACE PROPERTIES

946 IONIZING RADIATION

STUDY ( Circle No's wanted )

937 MEDICAL ULTRASONICS

938 ACOUSTICS

939 RADIOMETRY/PHOTOMETRY

940 SPECTROPHOTOMETRY

941 FAR UV RADIOMETRY

942 OPTICS

944 PHYS. PROP. ATOMS/MOL.

945 SURFACE PROPERTIES

946 IONIZING RADIATION

STUDY ( Circle No's wanted )

937 MEDICAL ULTRASONICS

938 ACOUSTICS

939 RADIOMETRY/PHOTOMETRY

940 SPECTROPHOTOMETRY

941 FAR UV RADIOMETRY

942 OPTICS

944 PHYS. PROP. ATOMS/MOL.

945 SURFACE PROPERTIES

946 IONIZING RADIATION
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TO: PROGRAM INFORMATION OFFICE

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BOULDER, COLORADO, USA 80302

FROM: NAME: Place

Stamp

TITLE: Here

ORGANIZATION:

ADDRESS:

CITY/STATE:

COUNTRY/ZIP:

TO: PROGRAM INFORMATION OFFICE

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BOULDER, COLORADO, USA 80302

FROM: NAME: Place

Stamp

TITLE: Here

ORGANIZATION:

ADDRESS:

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TO: PROGRAM INFORMATION OFFICE

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BOULDER, COLORADO, USA 80302
t
•yS YEARS NBS