NATIONAL BUREAU OF STANDARDS REPORT

Final Report

on

655s

FIREPROOFING STRUCTURAL STEEL

by

E. W. Bender

and

M. W. Sandholzer

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

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NATIONAL BUREAU OF STANDARDS REPORT

NM MOJCCT NBS REPORT

1002- 20-10422 October 1, 1959 6558

Final Report

on

FIREPROOFING STRUCTURAL STEEL

by

E. W. Bender

and

M . V/ . Sandhol ze

r

Report to

Office of the Chief of Engineers

Bureau of Yards and Docks

Headquarters, U. S. Air Force

IMPORTANT NOTICE

rogress accounting documents Approved for public release by the mally published It Is subjected

Director of the National Institute of I’eproduction, or open-literature

Standards and Technology (NIST) Such permission Is not needed, on October 9, 2015. prepared if that agency wishes

U. S. DEPARTr^EMT OF COERCE

NATIONAL BUREAU OF ST

Intended for use yvithin the * to additional evaluation and r listing of this Report, either I the Office of the Director, Na

however, by the Government

to reproduce additional copie

NATIONAL BUREAU OF STANDARDS

FIREPROOFING STRUCTURAL STEEL

ABSTRACT

The effectiveness of fire-protective materials which

can be applied directly to structural steel members by

spray techniques was investigated. Test specimens were

prepared with protective coatings applied in 1/2- inch,

1-inch, and 2-inch thicknesses by a number of manufacturers, using normal field methods of application.

Results of small-scale fire tests on the protected specimens and studies of the corrosion effects and surface

characteristics of the coatings are reported. Results

of a full-scale fire test of a steel column protected by

a 1/2-inch coating of one of the products are also reported.

1, Introduction

In certain types of buildings such as aircraft hangars,

it is common practice to leave the structural steelwork unprotected, In cases where automatic sprinkler protection

cannot be furnished, the fire hazard may be high and losses

great. There are on the market today various materials which

can be applied by spray techniques directly to the steelwork,

and which are claimed to be useful for protection against fire.

The purpose of this investigation was to obtain performance

data on some of these materials.

2. Method of Investigation

In determining the suitability of a sprayed type of fire

protection material, a number of factors must be considered.

In addition to its primary function of providing protection

against fire exposure, the coating must be stable and well

bonded and should not introduce a corrosion problem when

applied to steelwork. Furthermore, its application must be

practical under usually experienced construction (Conditions.

2

The general plan adopted for investigation of the

coatings proposed a comprehensive study of small-scale

specimens, to be followed by a limited study of full-scale

specimens selected on the basis of data obtained from the

small-scale tests. The program carried out with small-scale

specimens included fire exposure tests on steel plate

specimens to which the coatings had been applied in thicknesses of 1/2 inch, 1 inch, and 2 inches. Specimens with

1/2-inch thick coatings were used for determinations of a

number of additional characteristics, which included bond

strength, dusting tendency, reflectance, moisture retention,

pH value, and corrosion effects. Thermal conductivity

measurements were made on 1-inch thicknesses of the coatings,

tested with no backing. On the basis of the data obtained,

one full-scale specimen was prepared and subjected to a fire

exposure test.

3. Materials

For the small-scale fire-test specimens, metal support

structures were prepared which consisted of a 2-foot square,

l6 gage, hot-rolled steel plate, spot-welded to a grid cgmposed of 3/V-inch cold- rolled plasterers' furring channels.

These specimen structures were sent to various manufacturers to be

coated with fire-retardant materials in the three thicknesses

of 1/2 inch, 1 inch, and 2 inches. Each manufacturer was

supplied with four specimen structures for each thickness,

two with the hot-rolled finish as received, and two shopcoated (one coat of "Rustoleum" ) . Metal grounds were welded

around the periphery of the surface to be coated, to insure

obtaining the proper thickness of the coating.

To provide specimens for the investigation of the other

properties under consideration, each manufacturer was supplied

with twelve 6-inch square specimen structures, of the same

construction as the fire-test structures and provided with

grounds for the application of l/2-inch coatings. Six of the

twelve were shop-coated and six were left with the hot-rolled

finish as received. In addition, two wooden frames, 8 inches

square by 1 inch deep and lined with polyethylene film, were

sent to each manufacturer for the preparation of specimens

for thermal conductivity measurements.

4

- 3 -

The coatings were supplied by eight different manufacturers and were said to have been applied with the same

equipment and techniques normally used in the field. In

some instances, the manufacturer indicated that his product

required a bonding primer and that such a primer had been

applied to the specimen structures before application of the

fire-retardant coating. During inspection of the specimens

for corrosion effects, evidence was observed that this primer

had not in all cases been generally distributed over the

6-inch square plates but had been applied at one or two spots

only. No similar inspection of the 2-foot square specimens

was made.

The following list gives the names of the participating

manufacturers, together with a brief note regarding the major

components of each product.

Air- 0-Therm Application Company

Jet-Sulation

A mixture of all glass fibers and binder.

Columbia Acoustics and Fire Proofing Company

Cafco Spray Standard Fiber

A mixture of all glass fibers and binder.

Keasbey and Mattison Company

Sprayed "Limpet" Asbestos

A mixture of all asbestos fibers and Portland

cement binder

Larson Products

"Plaster Weld"

A liquid bonding agent for plaster o A plaster of

perlite, asbestos fiber, and gypsum was applied

over the "Plaster Weld" by means of a plastering

machine.

National Gypsum Company

Thermacoustic

A mixture of mostly glass with some asbestos fibers.

Smith and Kanzler Jetbestos Inc.

Spray Craft

A mixture of glass and asbestos fibers and binder.

- 4 -

United States Gypsum Company

Audicote

A mixture of perlite, bentonite clay, and asbestos

fiber.

Zon-O-Lite Company

Zon-O-Lite Acoustical Plastic

A mixture of vermiculite, bentonite clay, and asbestos

fiber.

In surface finish, the coatings ranged from a felted

nap-like finish to a hard troweled surface. The average

densities of seven of the coatings, as applied to the firetest specimens, ranged from about 12-22 Ibs/ft^, with five

of the group falling in the range of 15-20 lbs/ft3. The

eighth product was a plaster bonding agent not intended as

a complete protective coating in itself, and the acoustical

plaster applied over it was decidedly heavier than the other

coatings, with an average density of about 50 lbs/ft3. With

most of the products the variation in density from specimen

to specimen was large, and ranged as high as 50-55 pei* cent

of the average in several cases.

Methods of Test

^.1 Small-Scale Fire Exposure

The tests were performed in a firebrick furnace that

forms a cube-shaped combustion chamber, the specimen, with

the fireproofed face down, providing the cover for the cube.

The furnace is gas fired and vented by means of a baffled flue

and chimney to the outside. The temperature in the combustion

chamber is automatically regulated so that it follows the

time temperature curve prescribed in ASTM Specification EII 95

"Standard Curve for Fire Tests." The times and temperatures

specified are lOOO'^F at 5 min, 1700®F at 1 hour, 2000®F at

h hours, and 2300°F at 8 hours.

The specimen is placed over the top of the combustion

chamber, with 1/2 inchi of the face of the specimen resting

on the firebrick wall on all sides. An asbestos or mineral

wool gasket is placed around the edges of the specimen to

minimize heat flow from the specimen.
ti

i .
- 5

-

A transducer made of insulating firebrick, 2 feet long

by 12 inches wide by 1 inch thick, is placed over the channel

iron backing of the specimen plate. The underside of the

transducer is blackened and thermocouples are placed on the

under and upper surfaces. Two pieces of asbestos millboard,

2k Inches long by 6 inches wide and 1/2 inch thick, with

thermocouples placed on the upper and lower surfaces, are

laid on either side of the transducer. Thus, a 3/^-inch

sealed air space is formed by the millboard and transducer

and the l6 gage steel sheet of the specimen. A thermocouple

is placed on the geometric center of the steel sheet to

indicate the temperature on the unexposed face of the fireproofed specimen. The transducer gives an indication of the

heat flow from the combustion chamber through the fireproofing

and steel sheet.

A reinforced sheet-metal pan, ^3 inches by 43 inches

with 2-fnch high sides, is suspended from the ceiling of the

test room. This pan is held 8 Inches above the top of the

transducer with the center of the pan above the center of the

specimen. V/ater is piped to the pan and the outlets are

arranged so that 1/2 inch of water covers the bottom of the

pan at all times. Records of the water flow rate and the

temperature of water entering and leaving the pan provide

another method of measuring heat flow from the specimen.

The end point of the test was considered reached when

the temperature on the unexposed surface of the steel plate

reached lOOO^F.

4.2 Thermal Conductivity

The thermal conductivity measurements were made in an

8-inch guarded hot-plate apparatus conforming to the requirements of Federal Specification LLL-F-321b and of ASTM Standard

0177-45. The specimens were removed from the wooden frames

and were air-dried to constant weight in an oven at 215°F

immediately prior to test. The loss of weight on drying

ranged from 0.8 to 2.5^ for the various coatings, except the

plaster coating which lost over 13^ due to partial calcining

of the gypsum at the drying temperature. Thickness of the

specimens, measured after drying, ranged from 0 . 89 to I.06

inches.
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- 6

^.3 Bond Strength

Specimens for testing the bond strength of the coatings

were prepared by securely cementing a 4—inch square steel

plate, with an eyebolt tapped into the center of the square,

to the surface of the 6-inch square specimen of the coating.

After conditioning at and 50^ RH for two weeks, the

specimen was suspended face downward and weights were added

to a bucket hung from the eyebolt until the test section

pulled away. Before test, a knife cut was made through the

coating all around the ^-inch plate so that only the ^-inch

square section was under test. The type of failure, whether

in the cohesive forces in the coating itself or in the bond

between the coating and the steel plate, was noted, as well

as the weight required to produce failure. Four specimens

of each coating were tested, two with the steel shop-coated

before application of the fire retardant and two without

shop-coating.

Dusting Tendency

The method devised for evaluation of the dusting tendency

was based on the erosion effects of an air stream directed

across the surface of the coating. The apparatus consisted

of a sheet aluminum funnel provided with a sheet metal cover,

to the underside of which was secured a holder to accomodate

the 6-inch square specimens in horizontal position. The air

inlet consisted of a 1/k inch copper tube with a flattened,

fishtail tip, introduced through the side of the funnel and

so positioned that the air jet was directed against the

horizontal surface of the specimen near one edge and at an

angle of degrees. The tip of the air inlet was 3A inch

below the surface of the specimen. The air stream was

directed over the specimen for 8 hours at a flow rate of

0,5 ft3/min, and the dust was collected at the bottom of the

funnel on a weighed filter paper. Two specimens of each

coating were tested. It is not evident to what extent the

method would simulate service performance.

5-, 5 Reflectance

Reflectance was measured with a Baumgartner reflectometer

,

which is described in the Illuminating Engineers Society

Lighting Handbook. The reflectometer provides a measure of

the fraction of incident light reflected by a surface.
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^.6 Moisture Retention

Equilibrium moisture content was determined under conditions designed to indicate the effects of both increasing

and decreasing ambient humidities. Constant humidity conditions at five different levels, namely, 17^ RH, 30^ RH,

5^^ RH, 80^ RH, and 93^ RH, were established by means of

saturated solutions of appropriate salts or the use of controlled rooms. It was not feasible to maintain all of the

humidity chambers at the same temperature, but they were all

within the range of 73-78°F except that for 80^ RH which was

maintained at 90°F. The samples were kept at a selected

humidity level until moisture equilibrium had been established,

as indicated by constant weight, and were then moved to a

different level and allowed to reach equilibrium, the moves

being selected to provide various degrees of increase and

decrease in humidity. Values obtained by oven-drying at

ihO'^F were used as the dry weights of the samples.

The materials were prepared for these tests by removirg

the coatings from the steelwork and grinding them to a

relatively fine condition. Each sample consisted of an amount

of the powdered material which could be contained in a 3-inch

watch glass without touching the flat plastic cover placed

over the glass during the weighing operations, which were

conducted under the prevailing laboratory humidities.

^.7 Determinations of pH Values

For these determinations, samples of the powdered coatings,

as prepared for the moisture retention work, were used. A

5-gram sample of the coating was stirred vigorously for 5 mimutes with 75 ml of distilled water in a l50-ml beaker. After

being allowed to settle for 30 minutes the pH value of the

supernatant liquid was determined with a pH meter. The

beaker was covered and the settling allowed to continue for

6^- hours, after which the pH value of the supernatant liquid

was again determined.

4.8 Corrosive Effects

In order to assess the corrosive effects of the coatirigs

on the steel plates, specimens which had been stored for

20-21 months at 75*^F and 50^ RH were carefully examined. Each

, specimen was cut in halfisw>d the coating remov-ed frcfn the

plate. The plates -were then inspected by personnel specializing in corrosion problems and familiar with common corrosion

experience

- 8 -

^.9 Full-Scale Fire Test

After consideration of the data obtained in the smallscale fire tests and other studies, the Thermacoustic coating

manufactured by the National Gypsum Company was selected for

a full-scale fire test. A 1/2 inch Thermacoustic coating

was applied over a special bonding primer to a 13-foot column

consisting of a 6 inch by 6 inch, 20-lb stancion section.

The application was made by a local contractor approved by

the National Gypsum Company and was supervised by a representative of the National Gypsum Company. The column was conditioned at 75°F and 50^ RH until moisture equilibrium had been

reached, as indicated by constant weight of a sample of the

coating, prepared by filling a metal pan 12 inches square and

1/2 inch deep.

The column was tested in accordance with the ASTM Standard

Methods of Fire Tests of Building Construction and Materials,

E119-50. A load of 80,500 lbs was applied to the column

during the test, and the time when the column had lost 75^

of its maximum expansion was taken as the criterion of failure.

The average temperature of the steel in the column at four

different levels (approximately 2 feet, 5- feet, 6 1/2 feet,

and 9 feet from the base of the column, respectively) was

determined by means of six appropriately placed thermocouples

at each level.

Before testing the column, measurements were made of the

actual thickness of the coating at each of the four levels

where the thermocouples were attached. At each level, measurements were made at 28 suitably spaced points. The individual

readings showed thicknesses ranging from 1/8 inch to 1 1/8 inches,

and the average for all of the measurements was 39/6^ inch,

or nearly 5/8 inch. The average thicknesses at the separate

levels were 5/8 inch, 9/16 inch, 35/65- inch, and 5-7/65- inch at

the 2-foot, 5—foot, 6 1/2-foot and 9-foot levels, respectively.

5. Results and Discussion

5.1 Fire Endurance

Results of the small-scale fire tests are given in Table 1,

where the materials are listed in the order of performance in

the 1/2-inch thickness with that showing the longest average

endurance listed first. The specimens for which no results are

given had erack^^d^'-and were not suit ahle'^ftir testing.

~ 9 “

There appeared to be no consistent correlation between

the performance of the coatings and either their density or

the particular fibers or minerals used. The fire endurance

was evidently an Individual characteristic of each coating,

practically of each application. Although, in some instances,

the results suggest a decided difference in the fire endurance

of the specimens on shop-coated steel and those on steel with

the hot-rolled finish as received, the variation between

individual specimens of both types was so great that such

differences must be considered largely fortuitous.

All except one of the coatings provided sufficient protection to keep the temperature on the back of the plate

under 1000*^F for at least 3 hours when applied in the 2-inch

thickness, and for at least 1 hour applied in the 1-inch

thickness. In the 1/2-lnch thickness the period of similar

protection ranged from about 1/2 to 1 hour for the different

coatings. Performance in the l/2-inch thickness is of particular interest inasmuch as coatings of that thickness can

be applied in one operation, whereas the greater thicknesses

require two or more separate applications. The Thermacoustic

coating applied by the National Gypsum Company appeared to

give somewhat the longest period of protection in the 1/2 inch

thickness, with an average time of 70 minutes before the

temperature at the back of the plate reached lOOO^^F,

In the full-scale fire test of the 13-foot column protected by a nominal 1/2-inch coating of Thermacoustic, load

failure occurred at 4l minutes. The average temperature of

the steel at the level about h feet from the base of the

column reached 1000°F at 3^+ niin 35 sec, and one point at that

level reached a temperature of 1200°F at 3^ min 12 sec. The

coating adhered well to the steel throughout the test, and

showed no tendency to loosen or spall.

5.2 Thermal Conductivity

Results of the thermal conductivity measurements are

included in Table 2. The values given are the averages for

two specimens of each coating, and the densities were determined

after conditioning at 2l5“F for test. The thermal conductivity

values showed no correlation either with density or with fire

endurance as determined in the small-scale fire tests.

- 10 -

5.3 Surface Characteristics

The results obtained in the determinations of dusting

tendency and reflectance are also shown in Table 2, The

weights of dust dislodged from the coatings during the

8-hour application of the air stream ranged from .005 to

.010 gram.

The reflectance values for the various coatings ranged

from 32 to 59 pe^' cent of the incident light reflected.

The higher of these values would compare approximately to a

concrete pavement or a light §ray, painted wall, which

generally reflect from 50 to bO per cent of the incident

light.

5.^ Bond Strength

Results of the bond strength measurements are shown in

Table 3* In general, the coatings were effectively bonded

to the metal so that either the cohesive forces within the

coating itself failed before (or simultaneously with) the

coating-metal bond, or a very strong force was required to

pull the coating from the metal. With one product, the

U. S. Gypsum Company Audicote applied to metal which had not

been shop-coated, the coating-metal bond failed under relatively low force, probably due to rust formation. Shopcoating of the metal appeared highly advantageous in this

case, although it did not significantly affect the results

obtained with the other products.

5.5 Corrosion and Related Factors

In addition to an inspection of specimens stored for an

extended period, it was of interest to obtain some information on the moisture adsorbing tendencies and the alkalinity

or acidity of water extracts of the coatings, in connection

with the possible corrosive effects of the coatings on steelwork. The program followed in determining the moisture

content of the coatings was designed to indicate a possible

hysteresis effect under conditions of adsorption and desorption,

but sufficiently precise control to demonstrate this effect

did not prove feasible with the facilities available. However,

the data provide a comparative measure of the tendencies of

the various coatings to adsorb and retain moisture, and the

moisture content (per cent of moisture determined on the basis

%f the dry weight of** the ^specimen) for the tvi^ humidity levels

of 5^^ and 80^’ -RH are shown in Table 4’. It- appeared that none

of the coatings adsorbed an excessive amount of moisture.

11

The pH values obtained for water extracts of the

coatings, after settling for 1/2 hour and for 6h hours,

are also given in Table All of the values indicate a

distinctly alkaline condition.

The actual corrosion observed upon inspection of

specimens which had been stored 20 months, was mild and

would not be expected to impair the service life of the

steel. It is believed that such corrosion as was found

developed immediately after application of the coatings,

and that, after the coating had dried, the attack ceased

or decreased to a minimum. The coatings are listed in

Table 5 in the order of increasing corrosion, with notations

as to the extent of corrosion observed. All of the specimens except the first two in the list showed some rust on

the exposed upper edges of the angle iron grounds which had

been welded to the plates as a gage for proper thickness of

the coating. Although corrosion was not severe on any of

the specimens, shop-coating of the steel evidently provided

some protection against attack in every instance.

6. Conclusions

Dependable uniformity in application of the coatings

by the usual spray techniques appears to be difficult and

seldom achieved. Hence, the results obtained in tests of the

specimens submitted should be interpreted with considerable

allowance for probable variations.

The small-scale fire endurance tests, while directly

applicable only to panel type protection, indicated that

a 1-lnch thickness of any of the coatings tested should, on

the average, provide reasonable protection for about an hour

or more. The best of the coatings appeared to offer such

protection in a 1/2 inch thickness. In the full-scale column

test, the 1/2-inch application of the coating selected as

most promising in the small-scale tests, provided reasonable

protection for about ^0 minutes.

Most of the coatings showed satisfactory bonding to

either the shop-coated or unpainted metal. However, the

Audicote manufactured by the U. S. Gypsum Company tended to

rust unpainted metal to an extent which decidedly weakened

.the bond, and shop-coating of the metal appeared necessary to

provide a.*sHrong bond in that case.‘ ‘'The Plaster Weld manufactured by Larson Products Company failed to bond the l/2-in

thickness of plaster during the small-scale fire tests, but

performed satisfactorily with the thicker plaster coatings.

- 12

As tested, the coatings appeared to present no serious

dusting problem. It is not known to what extent these tests

could be considered applicable to field conditions. Light

reflectance appeared to be quite similar to or somewhat less

than that of a concrete pavement.

None of the coatings exhibited an equilibrium moisture

content of excessive amount in the 50 to oO per cent relative humidity range, and all showed alkaline reactions in

water extracts. None caused serious corrosion which would

impair the service life of the metal when applied to either

shop-coated or unpalnted steel, although in some cases, corrosion of the unpainted steel was sufficient to endanger the

coating-to-metal bond. Shop-coating of the steel reduced

corrosion in all instances.

USCO^-NBS-DC

Table 1. Results of small-scale fire tests

Manufacturer Finish

Density and time

1000°

plate

'F reached

Fiber

and

Material

on

Plate

1/2 in

thick

L 0 1-ln.

thick

2-in.

thick

or Mineral

Ibs/ftd min lbs/ft3 min Ibs/fth min

Natl Gypsum Co.

Thermacoustic

Unpalnted

It Shop-coated

It II

27.2

2>+.3

28.4

28.1

66

57

88

JZ1_

20.1

22.4

18.4

21.7

135

170

77

200

18.6

18.6

17.5

..llA

352

315

310

202

Glass

and

asbestos

Average 27.0 20.6 i46

' 18.0 "2W

U, S. Gypsum Co.

Audicote Unpainted

It Shop-coated

II It

20.3

20.7

17.5

17.6

63

58

40

41

19.6

19.2

17.7

20.4

164

170

75

7.5.„

19.4

18.3

301

248

Perlite

and

asbestos

Average 19.0 50 19.2 121 18.8' "2^

Air-O-Therm

Application Co.

Jet-Sulation

Unpalnted

II Shop-coated

II II

26.4

25.1

21.4

15.9

39

43

45

16.8

16.0

15.6

23.3 ...

68

68

47

20.8

16.4

130

75

All

glass

Average 22.2 4o 17.9 58 1^~,6 102

Keasbey & Mattison

Co. Unpainted

Limpet " Shop-coated

n It

12.9

13.2

12.4

12.7

44

35

38

9.8

10.5

12.3

11.1

78

90

110

85

10.1

10.0

10.9

11.2

340

123

330

175

All

asbestos

Average 12.8 39 10.9 91 11.5 242

Smith c§: Kanzler

Jetbestos Co.

Spray Craft

Unpainted

ft Shop-coated

II II

21.1

16.3

16.7

15.2

63

32

25

22

13.6

14.3

l4.l

l4.8

91

74

70

50

13.3

15.0

14.3

19.0

316

398

350

380

Glass

and

asbestos

Average 17.3 38 i4.2 71 15.4 361

Zon-O-Lite Co.

Zon-O-Lite

Acoustical

Plastic

Unpainted

II Shop-coated

II II

16.8

16.9

18.0

16.8

29

33

46

35

18.2

18.2

15.8

16,0

93

75

55

60

16.8

16.0

16.7

13.3

278

290

283

290

Vermiculite

and

asbestos

Average iz.q_„_36_^ . 17^..,,.-_Zl_ 15.7 286

. Table 1. Results of small-scale fire tests (continued)

Density and time plate reached

Manufacturer Finish H OOO

o'F Fiber

and on 1/2 in. 1-in. 2-in. or Material Plate thick thick thick Mineral

lbs/ft3 min lbs/ft-5 min lbs/ft3 min

Columbia Unpainted 18.3 19.1 126 17.0 3>+5 All

Acoustics and " 16.7 3^ 18.5 155 18.2 39>+ glass

Fireproofing Co. Shop-coated 13.5 37 15.3 58 18.1 305

Cafco Spray " " l4.l 35 19.9 80 16.3 255

Average 13.6” _ .35 i8.2 P

[i

—

1

17.

k

32“? Larson Products

Co. Unpainted 5^.7 25* 53.5 75 54.7 k69 Perliti

Plaster Weld ” 33* 53.8 163 k7.k 398 asbestoi

Shop-coated 52.0 21* >+3.0 65 55.0 - and

It II \7t8 22* 39. 6_ 56 k3.6 20k gvDsum

Average 3k. 8 —.23 W.5 90 50.2

Plaster fell from steel plate at approximately 11 minutes

Table 2. Results of determinations of thermal conductivity and

surface characteristics.

Manufacturer Thermal Conductivity

and Data

Material Density Conductivity

Dusting

Results

(dust collected) Reflectance

lbs/ft3 BTU in/hr">Fft2 g

Nat '1 Gypsum

Co.

Thermjacoustic 20.8 0.3^ .0103 32

U. S. Gypsum

Co.

Audicote 18.5 0.68 .0072 59

Columbia

Acoustics and

Fireproofing

Co.

Cafco Spray 19.8 0.^-3 .0061 59

Keasbey and

Mattison Co.

Limpet 12.5 0«35 .0051 49

Larson Products

Co.

Plaster Weld ^6.1 0.79 51

Zon-O-Lite Co.

Acoustical

Plastic 15.8 0.65 .0054 48

Smith and

Eanzler

Jetbestos Inc.

Spray Craft 20.8 0o48 .0050 46

Air-0~Therm

Application

Co.

Jet-Sulation 20 . 0- 0.33 .0047 52
rMs

it

f

':ii

i4

-5 w

'

..V> • '

...

;;jf- : V-

' '

s

«

^ '‘ir.

T.

rif'

• V:-

iis

i.-J

I » 1 >

S'
Table 3 * Results of bond strength determinations

Manufacturer

and

MateriaH^

National Gypsum Co.

Thermacoustic

U. S. Gypsum Co.

Audicote

Columbia Acoustics

& Fireproofing Co.

Cafco Spray

Keasbey & Mattison Co.

Limpet

Zon-O-Lite Co.

Acoustical Plastic

Smith & Kanzler

Jetbestos Inc.

Spray Craft

Air-O-Therm

Application Co.

Jet-Sulation

Finish

on

Plate

Failure

Load

(lbs)

unpainted 60

shop-coated k2

unpainted 28

shop-coated 120

unpainted 8

shop-coated 8

unpainted 6

shop-coated 10

unpainted 115

shop-coated 132

unpainted 8

shop-coated 11

unpainted 18

shop-coated 18

Region of Failure

Within coating

fl M

Plate surface-rust

Plate surface

Within coating

n II

Within coating and on

plate surface

Within coating and on

plate surface

At scratch coat and on

plate surface

At scratch coat

Within coating

Within coating and

on plate surface

Within coating

II II

Table Results of moisture content and pH determinations

Manufacturer

and Moisture Content dH Values

Material RH . 80% RH 1/2 hr 6^ hr

% %

National Gypsum Co.

Thermacoustic « 85 6.72 9.3 8.3

U. S. Gypsum Co.

Audicote 1,71 5.69 9*7 8.7

Columbia Acoustics

& Fireproofing Co.

Cafeo Spray . 63 2.32 9.3 9.5

Keasbey & Mattison Coo

Limpet .67 3.66 11.1 10.7

Larson Products Co.

Plaster Weld .31 .95 8.6 7.7

Zon-O-Lite Co.

Acoustical Plastic 2.27 10.22 9.9 9.1

Smith & Kanzler

Jetbestos, Inc.

Spray Craft .65 2.32 9.1 9.7

Air-O-Therm

Application Co.

Jet-Sulation 1.75 4.55 9.9 9 o 7

Table 5» Observations on corrosion effects

Manufacturer

and

Material

Finish

on

Plate Corrosion Observed

1. Keasbey & Mattison Co.

Limpet

shop-coated No failure

2. Air-O-Therm Application

Co

.

Jetsul ation

shop-coated No failure

3* Columbia Acoustics

& Fireproofing Co.

Cafco Spray

shop-coated No rust on plate

4, National Gypsum Co.

Thermacoustic

shop-coated No rust on plate

5. Keasby & Mattison Co.

Limpet

unpainted Scattered pin-point

rust on plate

6. Air-O-Therm Application

Co.

Jet-Sulation

unpainted Scattered light, superficial rust on plate

7. Smith & Kanzler

Jetbestos, Inc.

Spray Craft

shop-coated Paint blistered in one

area on plate

8. Zon-O-Llte Co.

Acoustical Plastic

shop-coated Scattered pin-point

rust on plate

9. Columbia Acoustics

& Fireproofing Co.

Cafco Spray

unpainted Scattered light, superficial rust on plate

10. National Gypsum Co.

Thermacoustic

unpainted Scattered superficial

rust areas on plate

11. Larson Products Co.

Plaster WeiLd

shop-coated Scattered rust on faying

surfaces of plate and

angle grounds

Table 5« Observations on corrosion effects (continued)

Manufacturer

and

Material

Finish

on

Plate Corrosion Observed

12. U. S. Gypsum Co.

Audicote

13* Snith & Kanzler

Jetbestos, Inc.

Spray Craft

1^. Zon-O-Lite Co.

Acoustical Plastic

15. Larson Products Co.

Plaster Weld

l6. U. S. Gypsum Co.

Audicote

shop-coated Scattered rust on faying

surfaces of plate and

angle grounds

unpainted Medium superficial rust

on plate

unpainted

unpainted

unpainted

Few large areas medium

superficial rust on

plate and faying

surfaces

Medium superficial rust

over entire surface of

plate

General heavy superficial rust over entire

surface of plate

U.S. DEPARTMENT OF COMMERCE

Kridiiitk II. Miirll. r, Stvritary NATIONAL BUREAU OF STANDARDS

A. V. Aslin, Director THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its headquarters in Washington, D.C., and its major

laboratories in Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work. In general, each section carries out specialized research, development, and engineering in the

field indicated by its title. A brief description of the activities, and of the resultant publications, appears on the

inside of the fremt cover. WASHINGTON, D.C.

' Electricity and Electronics. Resistance and Reactance. Electron Devices. Electrical Instruments. Magnetic Measurements. Dielectrics. Engineering Electronics. Electronic Instrumentation. Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Optical Instruments. ' Photographic Technology.

Length. Engineering Metrology.

Heat. Temperature Physics. Thermodynamics. Cryogenic Physics. Rheology. Engine Fuels. Free Radicals Research.

Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics.

Electron Physics. Atomic Physics. Neutron Physics. Radiation Theory. Radioactivity. X-rays. High

Energy Radiation. Nucleonic Instrumentation. Radiological Equipment.

Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry. Inorganic

Chemistry. Electrodeposition. Molecidar Structure and Properties of Gases. Physical Chemistry. Thermocljemistry. Spectrochemistry. Pure Substances.

Mechanics. Sound. . Mechanical Instruments. Fluid Mechanics. Engineering Mechanics. Mass and Scale. Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer

Structure. Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal Physics.

Mineral Products. Engineering Ceramics. Glass. Refractories. Enameled Metals. Concreting Materials.

Constitution and Microstructure.

Building Technology. Structural Engineering. Fire Protection. Air Conditioning, Heating, and Refrigeration. Floor, Roof, and Wall Coverings. Codes and Safety Standards. Heat Transfer.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems. SEAC Engineering Group. Components and Techniques. Digital Circuitry.

Digital Systems. Analog Systems. Application Engineering.

• Office of Basic Instrumentation. • Office of Weights and Measures.

BOULDER, COLORADO

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Gas Liquefaction. Radio Propagation Physics. Upper Atmosphere Research. Ionospheric Research. Regular Propagation

Services. Sun-Eartlf'Relationships. VII F Research. Radio Warning Services. Airglow and Aurora. Radio

Astronomy and Arctic Propagation.

Batlio Propagation Engineering. Data Reduction Instrumentation. Modulation Systems. Radio Noise.

"Proposphcric Measurements. Tropospheric Analysis. Radio Systems Application Engineering. RadioMeteorology. Lower Atmosphere Physics.

Radio Standards. Nigh Frequency I'dectrical Standards. Radio Broadeasl Service. Nigh Ire<iuency Im-

•pedance Standards. Electronic, Calihration Ccjiler. Microwave Physics. Microwave Circuit Slandards.

Radio Communication and Systems. Low Frc(picncy and Veny Low I'nMpicncy Research. Nigh Ire- queney and Very Nigh Freepumey Research, lillra Nigh l‘'re(|u<'ney and Stqu’r Nigh I’requeney Ih'seareh. Modulation R(;scarch. Anietma Research. [Navigalion Sysli'ins. Svsleiiis \nal\sis. I'^ield 0])eralions.
NBS