NATIONAL BUREAU OF STANDARDS REPORT

3901

WEEP HOLES IN CONCRETE MASONRY PANEL WALLS

oy

C. C. Eishburn and Edward J. McCamley, Jr.

Report to

Office of the Chief of Engineers

Department of the Army

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

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NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

IOOO- 3 O-I4

- 8 OI March 10, 19^^ 3981

WEEP HOLES IN CONCRETE MASONRY PANEL WALLS

BY

C. C. Flshburn and Edward J. McCarnley, Jr

,

To

Office of the Chief of Engineers

Department of the Array

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, rep

unless permission Is 25,D,C. Such perr

caliy prepared If tt

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

n part, is prohibited

ndards, Washington

lort has been speclfiport for Its own use.
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WEEP HOLES IN CONCRETE MASONRY PANEL WALLS

by

0. 0. Pishburn and Edward J. McCarnley, Jr.

Abstract

Three small concrete masonry walls were subjected to exposure conditions simulating a wind-driven raino Weep holes were provided

in the vertical joints of the bottom course

of each wall and their effect in reducing the

leakage through the wall was studied. The

walls were tested in painted and unpainted condition and with weep holes open and closed.

1 « Introduction

A study of the function of weep holes in concrete

masonry panel walls, as used in framed concrete buildings,

was authorized by the Office of the Chief of Engineers,

Department of the Army, in a letter dated February 2i|,

1954-j signed by 1 . 0. Thorley, Jr., Acting Chief, Engineering Division, Military Construction.

Three small concrete masonry test walls were subjected

to exposure conditions simulating a wind-driven rain. Each

wall was built on a cast concrete base of special shape.

The base simulated the top of a concrete spandrel beam containing a recess in which the panel wall was supported at

an elevation below that of the floor level.

Permeability tests were made on the wall specimens with

the weep holes open (functioning) and with the weep holes

closed. Variables which were studied Included the effects

of painting the walls with a cementitious paint, perforation

of the top of the painted wall to simulate a horizontal

shrinkage crack below the soffit of the spandrel beam above

the panel, variation in the static air pressure (simulated

wind pressure) applied to the exposed wall face and the effects of dropping mortar through the vertical cells in the

block to the bottom of a wall.
2 .

2. Test Specimens

2.1 Walls

The three test walls were 8-in. thick, about IpO-in,

long and 50-in. high. Each wall was supported in a recess

1 1/2-in. deep formed in a poured concrete base resting on

a steel channel section (see figure 1). The concrete base

simulated the top of a spandrel beam on a concrete frame

building in which the bottom of the concrete masonry panel

wall is below the level of the concrete floor.

The concrete masonry units were of 8- by 8- by l6-in.

nominal size. All of the units used in the first course of

each wall were of half length. Walls A and B contained

units of cinder aggregate concrete. Wall C contained sand

and gravel aggregate concrete units. Some of the physical

properties of the concrete masonry units are listed in

table 1. All units were air dry when laid.

Mortar beds were placed under the face shells in all

walls. The vertical joints were buttered with mortar to

a depth equal to the thickness of the face shells. Care

was taken to prevent the dropping of mortar into the interior of all walls during their construction. However, a half trowel of mortar was placed into the bottom of each

cell in the first course of wall B, to simulate the careless dropping of excess mortar into a wall during its construction.

Weep holes were placed beneath each vertical joint in

the first course (see figure 2). The holes were formed

by placing a length of 3/8-in. dia rubber tubing in the

mortar bed. One end of the tubing protruded from the wall;

the other end was brought up vertically in the wall cells

to a height above any mortar droppings. After the walls

had been completed and the mortar had hardened, the rubber

tubing was withdrawn.

2.2 Paint coatings for walls

The paints applied to the exposed faces of the walls

were a base coat of a cement grout and a finish coat of

white Portland cement. The grout contained equal parts by

weight of high-early strength portland cement and sand passing a No. 20 sieve. The amount of water used to temper the

paints to a proper brushing consistency equaled 30 percent
3.

by weight of dry powder (cement and sand) for the grout and

40 percent by weight of powder (white cement) for the finish

coat. The amounts of the dry powders applied to the walls

are listed in table 2. The paints were applied to the

dampened wall surfaces with a stiff fibered fender cleaning

brush.

3 . Water Permeability Test Apparatus

The test exposures and the test apparatus were similar

to those described in NBS Reports BMS82 and BMS95. The exposed face of the test wall formed one side of a pressure

chamber. Water at the rate of l\.0 gal/hr was applied to the

top of the wall face from a tube containing a line of small

perforations spaced 3/4 in. apart. The test chamber, without the wall, is illustrated in figure 3. The air pressure

on the exposed wall face (inside the chamber) was maintained

during the test at either 5”, 10- or l5-lb/ft^ above atmospheric pressure; these pressures are equivalent to a hydrostatic head of about 1, 2, and 3 in., respectively. A wind

velocity of ^0 mph may produce a wind pressure of approximately 10 Ib/ft^. The tests were continued for a minimum

of one day. Except for the requirements of a rating of

Excellent, the water permeability test ratings of the walls

were similar to those described in Report BMS95 and are

listed below:

Excellent (E) - No leakage and no water or dampness visible on back of the wall (above the

flashings) at the end of 1 day.

Good (G) - No water visible on the back of the

wall at the end of 1 day. Less than $0 percent

of the wall are ai. damp at the end of 1 day. No

leaks through the wall at the end of 1 day.

Pair (P) - No water visible on back of the wall

during first 3 hours, but visible at end of

1 day. The rate of leakage through the wall

less than 1 liter/hr at the end of 1 day.

Poor (P) - Water visible on back of the wall in

3 hr or less and at the end of 1 day. Rate of

leakage less than 5 liters/hr at the end of 1 day.

Very Poor (VP) - Rate of leakage through the wall

equal to or greater than ^ liters/hr at the end

of 1 day.
4 . Concrete masonry walls rated as Good or better should

provide satisfactory protection against the leakage of winddriven rain. Walls rated as Poor or Very Poor would not be

likely to provide satisfactory protection against leakage.

4 . Test Procedure

The walls were first tested in the plain, unpalnted

condition with the weep holes open and then with the weep

holes closed. The static air pressure in the chamber was

equivalent to a hydraulic head of 2- or of 3~in. The weep

holes were plugged with corks but there was some evidence,

particularly in the later tests on the painted walls, that

air and water penetrated around the corks in plugged weep

holes. After the completion of these tests the walls were

painted on the exposed faces with a base coat of a portland

cement-sand grout and a finish coat of white portland cement.

The back of the painted walls were given a coating of white

wash to accentuate the appearance of any dampness penetrating the masonry during subsequent permeability tests.

The painted walls were tested with weep holes open

and then with weep holes closed, using air pressures equivalent to hydraulic heads of 1-, 2- or 3-in. After these

tests were completed, five 3/l6-in. dia holes were drilled

through the exposed face of the top course in each wall;

one hole being placed into each of the five cells in the

course. These holes had a combined area of O.I 8 sq in.,

approximately equivalent to the area of a horizontal crack

about 0.005 in. wide and 35-in, long. Tests were made on

the drilled walls with the weep holes open and then closed,

using air pressures equivalent to hydraulic pressure heads

of 1-, 2-, and 3 in.

After all of the above tests were completed, the weep

holes and the drilled holes in the top courses of the walls

were plugged and tightly sealed with mortar. A coating of

cement paint was then placed over the mortar plugs and the

walls were given a final test under a 3-in. hydraulic pressure head ( l5 Ib/ft^ static air pressure). The complete

test schedule is listed below in table 3.
5 . Test Data and Discussion of Results

5.1 Tests on the walls before painting

Data on the water permeability tests of the walls

made before the walls were painted are listed in table I4

.

,

Water readily penetrated the exposed faces of the walls

above the weep holes. Some of this water passed through

the masonry and first appeared as damp spots on the back,

unexposed faces, of the walls at points above the supporting base. This was most noticeable for walls A and C in

which the first damp spots appeared well above the base.

However, the first appearance of visible water on the backs

of all the walls was at the bottom of the wall and at the

elevation of the tops of the concrete bases.

With the weep holes open, all of the walls were rated

as Poor when tested under hydraulic pressure heads of 2

and 3 in. The time for failure slightly decreased and the

rate of leakage slightly Increased as a result of increasing the pressure head from 2 to 3-in. Wall C containing

the gravel aggregate block was significantly more permeable

than the cinder aggregate block walls A and B. Wall B containing mortar in the bottom was slightly but consistently

more permeable than was wall A.

When tested after closing the weep holes, the walls

were much more permeable. Wall A was rated as Poor for

pressure heads of 2 and 3 in. However, walls B and C were

rated as Very Poor and leaked considerably. In general,

the rate of leakage was doubled by Increasing the pressure

head from 2 to 3 in. Since much of the water penetrated

the walls above the weep holes there was little difference

between the appearance of the backs of the walls when tested

with the weep holes open and when closed. Figure I|. shows

the back of wall B after testing with the weep holes open

under a 3-in, pressure head. The illustration is typical

for both walls A and B when tested with the weep holes open

or closed. Wall C was 100 percent damp.

The tests on the unpainted and permeable walls showed

that the rate at which leakage water penetrated the wall and

flowed over the top of the recess was greatly reduced by the

use of the weep holes. An Increase in the wind pressure

(applied hydraulic pressure) had the same relative effect as

a decrease in the depth of the recess. For similar exposure

conditions, the wall B containing mortar droppings, was considerably more permeable than was wall A.
5.2 Tests on the painted walls

The data obtained from tests made after the walls were

painted and before holes were drilled in the top courses

are listed in table 5. As may be expected, there was no

leakage through the painted wall faces. Water that penetrated the open weep holes was absorbed and carried up into

the first and second courses of the masonry (see photographic figures 5j 6, and 7 for tests A-5 and A-6, and A-7,

respectively) . There was little difference between the performances of walls A, B, and C in these tests for like conditions of exposure. The height of capillary rise of

moisture into the masonry from water that had penetrated

the weep holes in the base was approximately the same for

all three walls and the height of capillary rise was not

much greater for a hydraulic pressure head of 2 or 3 in.

than for a head of only 1 inch.

From table 5, it may be noted that the walls were

rated as Good for pressure heads of 1 inch. For this pressure head, it is likely that water entering the weep holes

did not rise to the top of the 1 l/2-in. deep recess except

by capillarity. When the pressure heads were increased to

2 in. and to 3 in., visible water was noted on the backs of

the walls. The time required for water to become visible

decreased with increase in air pressure and, with one exception, rated as Fair, the walls were rated as Poor in

all of the tests in which the hydraulic pressure was 2 in.

or more

.

Plugging of the weep holes with tightly fitting corks

tended to reduce wall permeability (see table 5). However,

it is likely that some moisture penetrated the weep holes

around the periphery of the corks. The capillary rise of

moisture on the backs of the walls was nearly as great and

followed the same general pattern in tests made with weep

holes closed as was the case for the tests majie with the

weep holes open.

In general, the painting of the walls made them highly

resistant to water penetration and there was no water penetration except into the weep holes. This leakage water

penetrated upward by Capillarity and produced damp areas

on the backs for a height of 8 or 10 in. above the recess.

When the applied hydraulic pressure head exceeded the depth

of the recess, visible water appeared on the inner faces of

the walls just above the top of the recess. Dampness and
7 . visible water was noted in less time on the back of wall

B than was the case for wall A, It is possible that the

mortar placed in the bottom of wall B but not in the bottom

of wall A had an effect on the time interval required for

dampness to appear.

5.3 Tests on painted walls with drilled holes

Data obtained from tests made on the painted walls

after 3/l6-in. dia holes were drilled in the top course

are listed in table 6, Water readily entered the drilled

holes and penetrated to the backs of the walls. The backs

of walls A and B were similar in appearance after all tests

made with holes in the exposed faces, regardless of the

applied pressure heads and whether the weep holes were

open or closed. The back of wall C was nearly 100 percent

damp in all tests made with holes in the exposed faces.

The appearaice of wall B in test B-12 (see figure 8), was

not greatly different from its appearance in test B-2 made

before painting. With the exception of wall A in test

A-9 all of the walls leaked and were rated as Poor in tests

made with the weep holes open and as Very Poor with the

weep holes closed. As in previous tests, the wall B was

slightly more permeable than was wall A.

The tests indicate that only a few small openings are

needed in the exposed face of a wall to permit the leakage

of a considerable amount of wind-driven rain. With the weep

holes open the rate of leakage through the wall was greatly

reduced from that observed when the weep holes were closed.

Although permitting the entrance of some water and a resultant capillary rise, the weep holes may prevent excessive

leakage through walls that contain shrinkage cracks.

5.4 Tests on painted walls with all openings

tightly sealed with mortar

After the completion of the tests previomsly described,

(section 5.3 and table 6) the weep holes and the drilled

holes in the top courses of the walls were plugged with

mortar and the mortar patches were painted with one coat

of white cement. Since bases of the sealed walls contained

some water which did not readily drain from the weep holes,

it was necessary to dry the walls for two or three weeks

before the final tests. After this drying period the walls

were subjected to a test with a hydraulic pressure of 3 in.

(as indicated in tests A-II4., B-l 5 , and C-lL|. in table 3 ).
8 . After a test exposure of one day, there was no water or

dampness on the backs of any of the walls all of which

were arbitrarily rated as Excellent (see figure 9). It is

probable that if the weep holes had been tightly closed

during tests A-8, B-8, B-9, and C-8 (tables 3 a.nd 5 ) there

would have been no water penetration or dampness and the

walls would have been rated as Excellent,

6. Summary of the Discussion

1. Before painting, the concrete masonry walls were

highly permeable and leaked when subjected to conditions

simulating a wind -driven rain. The rate of leakage was

much greater when the weep holes were plugged and could

not function .

2. The painted walls were highly resistant to water

penetration. When the weep holes were tightly closed,

there was no indication of dampness or leakage on the inside wall faces. When the weep holes in the p-alnted walls

were open, water penetrated them and tended to fill the

bottom of the walls to a depth equal to the applied

hydraulic pressure head. Some of this moisture rose in

the masonry by capillarity producing damp areas and visible water on the inside faces of the walls to a height of

8 or 10 inches.

3. When tested with the weep holes open, the painted

walls were much less permeable when the applied hydraulic

pressure head was less than the depth of recess in which

the walls rested. The walls were significantly more permeable when the applied pressure exceeded this depth,

4. There was no certain indication that the droppings

of mortar into the bottoms of the walls had an important

or significant effect on permeability. However ^ as formed

by the use of long rubber tubing, the weep holes were not

covered and sealed by the mortar droppings. Wall B, containing mortar droppings was consistently more permeable

than was wall A containing no droppings. Since the weep

holes were formed by the use of long pieces of rubber

tubing it is unlikely that the holes were sealed and the

effect of the .Tnartar droppings was, therefore, not fully

determined

.
9 .

5 . Cutting of holes in the upper faces of the painted

walls greatly increased their permeability. As in tne case

of test on the unpainted walls, the rate of leakage was

greatest with the weep holes closed.

6. Weep holes do provide an entrance for wind-driven

rain into the masonry. This may possibly result in objectionable moisture and dampness at the bottom of the inside

wall faces. If it is reasonably certain that no shrinkage

cracking or other structural damage will occur, the weep

holes may be eliminated. If severe shrinkage cracking does

occur, the rate of leakage through the masonry may be greatly

reduced through the use of weep holes. However, such shrinkage cracking will further Increase the wet and damp areas on

the wall face and such dampness may extend to greater than

mid-height of the wall.

Where highly water resistant walls are desired, it may

be advisable to reduce and control shrinkage cracking rather

than to invite moisture penetration and dampness by the use

of weep holes.
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Finish coat

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p

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o

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p

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p

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pH

5

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r

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o i>^

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. * . O O C\J o

pO O- IP p CO

o o o

OJ C\J CM CM

P P P P

© © © ©

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I—I I—I I—I fciO

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<H CQ o

P P P poo 000

fp Ph P-l

p

oo

P-.

u\o o o PP o

II

P CM O • • • O O ro I—

I

O P CO ro

_::fP P CM p 0 0 0 0000 0000

CO CO CO POO CA CO CO 0 CO P cH

• p p 0 1—1 1—1 0 0 0 p 0

0^0 0 0000 0000

COCOIA CA CO pp- CO CO P P vQ POO 0 OOP 0 0000

0000

rococo 00

P P P P

© © © ©

Ph Ph Ph Ph 0000

CM CM CM bD

I I I >

<3 PQ o C

^ p p O o o O o o

p P-* (X, PL, o [>s ©

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> > >

Ph

vD O O P vD '

CM • • • • O vD 0*5 CM P I 1

O ^

CM rH I—I I—

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CM CM CM CM

td Tli 0 Td nd Td 0

© © © © © © © ©

w W M m m w w m 0 0 0 0 0 0 0 0

1—

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P

0 0 0 0 0 0 0 0

CO CO CO

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1 1 1 > 1 1 1 >

PQ 0 <3 <! PQ 0 <

P P

o o

o o

P Ph Ph O

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© ©

> >

CO CO O

PvO

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©

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CM P

^

COCO P cr POO o

0000

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LA10 CO _zt 000 O

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CO CO CO CO

Table

5.

Tests

on

walls

after

painting

TPj TPS '0 0 Ph Ph !h Ph Ph Ph Ph Ph 0 0 Ph Pi Ph o o o o •H O O O O O O O O O O .H •H o o o o Cd o o O O o o O o O O Cd Clj O 0! cil C5 [x. Pm Ph Ph Ph Ph Pu, C5 Ph JJh

e o

aJ

t:! C

aJ (D

CDSh -P

cjj cd

t>5

cti

-pC

CDO

CDa

O lA O "LA AJ I—i OJ I—

I

O O O O

AJ A) C\J AJ O O O OAJ AJ AJ C\J lA lAlAlA lA

I—I I—I I—I I—I I—

I

cJ CQ •H 0 ^ -P ®

oJ CCi S

^

o o o o

i-:i o o o o

lAlA

O O• • o o

o o o o o

0

p

cdo

•H

'O•H

0 5

I iH AJ 1 III I • • I I I

'

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n

cd0

!h rH•H

cd Ch

inO

0

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O «H

Ph -P W 0 Tj

Tj Cd >s-P

Ph Cd

pd 0

W w n, w ^

O vD (0 vO lAAJ A- lA pn,0

O vO vD AJ 1—1 1—

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CO j 1 vD

1 1 • • _d-o o 1—

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AJ O O o o

Ph0

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o

ft o

A-OO O

Ph H AJ AJ 22 O 0 AJ H H AJ vD

1—

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1 1

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AJ

_d-c\i O AJ o

AJ

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(—

1

S S cd 0 ... *

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Q

O O O o o o o o O O O o I—

i

o o o o

HHH iH AJC\JAJAJ cAr^r^rn, oj rAcA'^cA

1 fto 0 0 0 ^ 0

•H w 0 0 CD ® 0

0 PH ft 0 PH a PH PH PH PH PH pH PH PH PH PH M m n g

n C o 0 H 0 0 0 0 0 0 0 0 0 0 0 0 o o o O •H 0 O ft ft ft ft ft ft ft ft ft ft ft ft 1—1

1—

1

1—

1

o 0 :s 0 o o o o o o o o o o o O o o o o

0 bD

• bO bO bO W • lAUNlA > 0 0 0 > A- A- A- > CO CO qsQO >

0 o 1 1 1 <3 1 1 1 <3 1 1 1 <3 1 1 1 <3

E-i ts; <U PQ O <3 pq o <3 PQ O PQ <13 PQ ^

Table

6

.

Tests

of

painted

walls

after

drilling

holes

in

top

course'

bOd o o o o

o o o o

P-l Ph Ph P-l -p P p P P P P P P P P P P

03 •H 0 0 0 000 0 000 0 t>s I>s 000 0 000 0 000 0 P P P P

[X| (P P^ CP CP CP P-I CP CP CP CP CP 0 0 0 0

> > > >

PiS

03 03 -P

Tzi t:3 0

0 0

03 © 1— 1-A 0 0

1

0 lAO 0 LA lA lAlAlA 0 lAlA 0 lA

© P o-co 0 CO o-co 0 CO O- A- 0 CO A-r-o CO

P -P <H 0 1 1 t 1 1 1 <3; o3 0 a

E <+H 0

0 0 bO e 03 p 1A

•H © B H CM 1 1 0 C^vO fA vD CA TA H l>- co CM 0

0 Hi 000 0 000 0 000 0 'IfWD CA A-

?H Pi S:h o o o o o o o o

P-I Ph Ph

t>i ^

Jh Pi iP P

(D <D (D. ©

> > > >

iAT-r\o r^o-o

^^

CO ooo Q

rH

-p

03O

•H

TZi •H

CQ03©

Pi0

rH•H

03 <H

PiO

Ph ^

rQ 0

s

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s

a

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m -P •H 03 C3 > 12 O

o

Pi

ja' 03 a rO Q

A-"LA lA 1—

1

MD A- CAlA CO <A vOlAlA TA

1 fAA A-CM MD CO 1 CM \1AC0 A CM A- A1 • • • • • • 1 • • rD| • • • • • • 0 iH H 0 0 0 0 0 0 0 rH 0 0 0

lACM vO -z± 0 COIA 1—

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A-CA <A CO (A CA lAfA 0 fA

C"— (—i I—

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lA 0 A vO CO A fA \ 0 H A 0 fA lA

• • • *

• • • • lAO iH A H 0 0 0 000 0 '0 0 H 0 0 0

fACA 0 A fA A-O 0 fA 0 A CVJ A r—

1

fA A fA

A 0 1—

1

rH H 0 0 rH 1—

1

1—

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1—

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1—

1

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1

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1

• • • • • • • • • • • • • • • • 000 0 000 0 000 0 0 0 000 0

I o O «H

t>sH^ W K•H I—I I—

I

CM CM C\J CM ro ro CM CM CM CM rn rn ro

'H0 iri TZi t3 TZi TZi

1 zn 0 0 © © © © © ©

tz3 0 Cii 0 0

c 0 0 0 0 0 0 0 0 w m W w m w 0 0

0 0 0 1—

1

(0 0 0CD 0 0 0 0 0 0 © © 0 0 0 0 0 0 0 0

0 •H 0 0 p^ !Oi CP P^ fP CP CP CP CP CP CP 1—

1

1—

i

1—

1

1—

1

1—

1

1—

1

1—

1

1—

1

0 A 12 Xi 0 0 0 0 0 0 0 0 0 <D 0 0 0 0 U 0 0 0 0 0

-P 0 bO 0 1—

1

0

« bO 1—

1

A 1—

1

bO A (A A bi) AH-A

• bO m • 0 1—

1

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1

1—

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1—

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1—

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1

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1 1 < 1 1 1 <1; I 1 1 <u 1 1 1 <i: EH C PQ 0 PQ 0 CQ 0 < CQ 0 c PQ 0

A

3

/l

6

-in.

dia

hole

was

drilled

into

each

of

the 5

cells

in

the

top

course

of

each

wall.

Wall

in

damp

conditon

when

test

was

started.

•XC

XddV

" ,r _J[ n'10

ml®N

U)|tO N I

FRONT ELEVATION SECTION A-A

Fis. 1 - Details of a typical wall specimen,

ALUMINUM

FOIL

DRIP

FLASHING
ft.';

— w

If-?/'
Pig. 2 - Front elevation (exposed face) of wall A, showing

weep holes.
1
i

I

I

I

I

I

Fig. 3

- Permeability test chamber, showing method of applying water to the wall face.

Kw—

r

Fig. 4. - Back of wall B after test B-2; exposed face not

painted, weep holes open, pressure head of 3-in.

I
ys;

i.

V,

» 4k

I
I

!

i

Pig. 5

- Back of wall A after test A-^; face painted, back

whitewashed, weep holes open and pressure head

of 1-in.
r

V .
m

of 2-in


i-iL
Pig. 8 - Back of wall

B after test B-12. Holes drilled, in

top of exposed face, weep holes open, pressure

head of 3~in,
*

*

s: f't,

«
Pig. 9 - Wall B after test B-l5. Test made after all

openings in wall face had been sealed.

T

T" T’—

r

I I I

I

- I • I

•

I

'1 ' I I

* n I I

*

I

'

I

* I

* I ' I4fl
i
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major portion of the Bureau’s work is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Commission. The scope of activities is suggested by the listing of divisions and sections on the

inside of the front cover.

Reports and Publications

The results of the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project

or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office; The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

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which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications: The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 460, Publications of

the National Bureau of Standards ($1.25) and its Supplement ($0.75), available from the Superintendent of Documents, Government Printing Office. Inquiries regarding the Bureau’s reports and

publications should be addressed to the Office of Scientific Publications, National Bureau of

Standards, Washington 25, D. C.