jonal Bureau of Standards C-^fU^

Library, N. W. Bidg.

AUG 1 9 1952

Fire Resistance of Walls of GravelAggregate Concrete Masonry Units

United States Department of Commerce

National Bureau of Standards

Building Materials and Structures Report BMS120
BUILDING MATERIALS AND STRUCTURES REPORTS

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BMSl Research on Building Materials and Structures for Use in Low-Cost Housing * BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions.- lOfi BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 15ji BMS4 Accelerated Aging of Fiber Building Boards 10^ BMS5 Structural Properties of Six Masonry Wall Constructions 15^ BMS6 Survey of Roofing Materials in the Southeastern States 15^ BMS7 Water Permeability of Masonry Walls * BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 15^ BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs lOjS BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions

Sponsored by the H. H. Robertson Co 10^ BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 10^ BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and

Roofs Sponsored by Steel Building, Inc 15^ BMS13 Properties of Some Fiber Building Boards of Current Manufacture 10^ BMS14 Indentation and Recovery of Low-Cost Floor Coverings lOfS BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored

by the Wheeling Corrugating Co 10^ BMS16 Structural Properties of a "Tilecrete" Floor Construction Sponsored by Tilecrete

Floors, Inc 10^ BMS17 Sound Insulation of Wall and Floor Constructions 20^ Supplement to BMSl 7, Sound Insulation of Wall and Floor Constructions 5^ Supplement No. 2 to BMS17, Sound Insulation of Wall and Floor Constructions 10^ BMS18 Structural Properties of "Pre-fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation lOf. BMS19 Preparation and Revision of Building Codes t BMS20 Structural Properties of "Twachtman" Constructions for Walls and Floors Sponsored

by Connecticut Pre-Cast Buildings Corporation 10^ BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association 10(i BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 10^ BMS23 Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick

Manufacturers Association of New York, Inc lOfi BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile Cavity-Wall Construction Sponsored by the Structural Clay Products Institute. _ 15^ BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions, Floors, and Roofs 20^ BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction

Sponsored by the Nelson Cement Stone Co., Inc lOfS BMS27 Structural Properties of "Bender Steel Home" Wall Construction Sponsored by the Bender Body Co 10»5 BMS28 Backflow Prevention in Over-Rim Water Supplies 15<S BMS29 Survey of Roofing Materials in the Northeastern States 20i

BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas

Fir Plywood Association 15fS BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions

Sponsored by The Insulite Co 25^

* Out of print.

t Superseded by BMS116.

[List continued on cover page iii]
UNITED STATES DEPARTMENT OF COMMERCE . Charles Sawyer, Secretary NATIONAL BUREAU OF STANDARDS . E. U. Condon, Director

Fire Resistance of Walls of GravelAggregate Concrete Masonry Units

by Harry D. Foster, Earl R. Pinkston, and S. H. Ingberg

Building Materials and Structures Report 120

Issued March 30, 1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 15 cents
Foreword

This is the second, report issued by the National Bureau of Standards

dealing with the fire resistance of walls of concrete masonry units. The first report, Building Materials and Structures Report 117, dealt with walls buUt

from units made with cinder, pumice, expanded slag, or expanded shale aggregates; this report deals with walls buUt of units made with calcareous or siliceous

gravel aggregates.

The information given in this report should be helpful to those using

locally produced gravel-aggregate concrete masonry units in residential and

commercial buildings.

E. U. Condon, Director.

II
Fire Resistance of Walls of Gravel-Aggregate

Concrete Masonry Units

by Harry D. Foster, Earl R. Pinkston, and S. H. Ingberg

Fire-endurance test results for 12 walls of gravel-aggregate concrete masonry units are given and hose-stream test results for three of the walls. The concrete units used in five of the

walls were made with calcareous aggregates representing the group of natural aggregates

less susceptible to damage by fire. The units used in the other seven walls were made with

siliceous aggregates representing the group more susceptible to fire damage. The constructions included 4-in. nonload-bearing partitions and 8- to 12-in. load-bearing walls. The

fire resistance of the 4-in. unplastered partition of units made with calcareous aggregates

and of the 4- and 8-in. walls of units made with siliceous aggregates were limited to 1 hr or

less either by collapse or load failure. The values for the 4-in. plastered partition and the

8-in. load-bearing walls made with calcareous aggregates ranged from 1 hr 51 min for the

partition to 3 hr 57 min for one of the 8-in. load-bearing walls, and were determined by the temperature rise on the unexposed surface. The values for the 12-in. single-unit plastered

wall and the 12-in. two-unit wall of siliceous aggregates were 5 hr or more and were limited by the temperature rise on the unexposed surface. The hose-stream tests conducted at the end of the fire-endurance tests indicated that masonry walls built of units made with calcareous aggregates would meet the requirements

of that test. Walls of units made with siliceous aggregates that were 8 in. or less in thickness

in most cases had fire-endurance values of less than 1 hr and did not require the hose-stream

test. Walls of units thicker than 8 in. made with siliceous aggregates that withstood long

fire exposures may be expected to meet the hose-stream test requirements.

CONTENTS

Page

Foreword ii

I. Introduction and scope 2

II. Materials 2

1. Concrete masonry units 2

(a) Aggregates 2

(b) Proportioning 3

(c) Molding and curing 3

2. Mortar and plaster 3

3. Tests 4

III. Test walls 4

1. Construction 4

2. Size 5

3. Restraint and loading 5

4. Workmanship 5

5. Finish 5

6. Storing and aging 5

IV. Method of testing and equipment 6

1. Wall-testing furnace 6

2. Temperature measurements 7

3. Deflection measurements .__ 7

4. Hose-stream test 7

V. Results 7

1. Log of tests 7 VI. Discussion of results 11

1. Effect of type of aggregate 11

2. Effect of loading and restraint on type of failure 11

3. Effect of strength of unit 13

4. Effect of plaster 13

5. Performance of cavity-type construction 13

6. Effect of combustible framed-in members 13

7. Resistance to hose-stream test 14

VII. Summary 14

1
I. Introduction and Scope

The fire resistance of walls of concrete masonry

units is governed to a large extent by the type of

aggregate used in the units. This has been shown

by the results of two series of fire tests of walls

and partitions conducted at the National Bureau

of Standards. One series of tests, the results of

which are given in an earlier report/ included walls

built of units made with lightweight aggregates.

A second series, the results of which are given in

this report, was conducted with walls built of

units made with sand and pebble aggregates.

From the standpoint of fire resistance, natural

aggregates for concrete may be divided into four

general groups; namely, (1) calcareous, comprising

chiefly limestone and dolomite; (2) trap rocks,

consisting largely of basalt, diabase, and dolerite;

I Fire resistance of walls of lightweight-aggregate concrete masonry units, BMSn7 (1949).

(3) granitic rocks, comprised largely of feldspar

and quartz, and rocks of cemented grains of

quartz, such as sandstone and quartzite; and

(4) siliceous, generally occurring as grains or pebbles of quartz, chert, or flint. ^ The aggregates

used in the units for the walls of the present series were of the calcareous and siliceous groups.

The present series included ten 4-, 8-, 10-, and

12-in. walls built of units made with calcareous

or siliceous aggregates. The results of this series of tests are supplemented by data from tests of

two 8-in. load-bearing walls of units made with

calcareous aggregates and tested at the Underwriters' Laboratories in Chicago.^

2 Influence of mineral composition of aggregates on fire resistance of concrete, Proc. ASTM, 29, pt. II, pp. 824-829 (1929).

3 Report on 8-in. bearing walls, Underwriters' Laboratories reports, re- tardants 2619 and 2619-3.

II. Materials

1. Concrete Masonry Units

The sizes and designs of the units are shown in

figure 1 . The sieve analyses of the aggregates are given in table 1. The physical properties of the

units are given in table 2. The materials are

identified in these tables with respect to the aggregates used in the manufacture of the units and

the walls into which the units were built. The

designation consists (1) of the letters C or S

representing the type of aggregate, calcareous or

siliceous; (2) H, P, V, E, or U representing the

sources of the aggregates, the first three being

from the Washington and the last two from the

Chicago area; and (3) the numbers of the test walls

1 to 10 and Ul and U2. Thus the designation

CEl refers to units made of calcareous aggregates

in the Chicago district and used in test wall 1.

(a) Aggregates

The sand and gravel used in the units for walls

Ul and U2 consisted of approximately 52 and 80

percent calcareous minerals, respectively, and can

be classed as calcareous. The aggregates used for walls 1, 2, and 3 were obtained from the same

district as those for wafls Ul and U2 and are also

Figure 1. Designs of concrete units used in fire-test walls. Table 1. Sieve analysis of aggregates used in concrete units

Type of aggregate Source Grade

Aggregate retained on sieve Fineness Designation of units in which aggrtjgates were

used

56 in. No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 modulus •

Siliceous V Sand.

Percent

1.6 Percent8.

1

Percent

21.9 Percent34.8 Percent64.

1

Percent

92. 7 Percent98.6 3. 21 Do V Gravel 4.3. 7 85.9 94.0 96. 4 97.9 99.

1

5.17 Do _ V Combined . 1.

1

20.0 43. 2 54.6 74.9 94.4 98.8 3.87 SV9 and SVIO. Do —- P do 3.0 16.0 28.0 45.0 76.0 94.0 2. 62 SP4, SP5, SP6, SP7, SP8, SP9, and SPIO. SH4, SH5, SH6, and

SH8. Do H do 4.0 17.0 28.0 47.0 76.0 98.0 2.70

Calcareous E Sand _ 5.0 19.0 34.0 54.0 88.0 89.0 2.98 Do E Gravel 1.0 90.0 96.0 97.0 98.0 99.0 100.0 5. 81 Do -- E Combined 21.0 34.0 45.0 62.0 89.0 99.0 3.50 CEl and CE3.

Do.2 U Sand 3.2

86.9

19.5 41.4 66.9 93.7 99.0 3. 22 Do U Gravel 99. 7 99.9 100.0 100.0 100.0 5. 86 Do u Combined . 24.2 38.6 56.0 74.5 95.4 99.0 3. 87 GUI and CU2.

1 The fineness modulus is an empirical factor obtained by adding the total percentages of sample retained on each of the sieves and dividing the sum by 100, Standard definitions of terms relating to concrete and concrete aggregates, ASTM Designation: C 125-.39.

' The data on the aggregates from source U were from the Underwriters' Laboratories reports, retardants 2619 and 2619-3. 2
Table 2. Some physical properties of the units used in test walls

Units Tests 2

Test walls

III WiilUIl units were

used Unit

designation

Type of aggregate used in units

Molding

process Average size Shell thick- ness

DeSign ' Cell area As delivered

Weight

After drying

Moisture content 3 Absorption

Compressive strength based on gross area

CEl CE3 CUl

Calcareous

._.do .,_do

Vibration..

do. Dry tamp..

do

in. 4.02 by 15.78 by 7.68.. 4.02 by 23.78 bv 7.98..

7.75 by 15.81 by 8.00..

7.75 by 15.81 by 8.00..

3.80 by 11.82 by 7.71..

3.80 by 11.88 by 7.93..

3.75 by 11.78 by 7.65.. 3.75 bv 11.81 bv 9.96..

7.80 by 15.8 by 7.74..

8.04 by 15.94 by 7.90..

7.76 bv 15.8 by 7.70.. 8.02 by 15.85 by 7.81.. 3.75 by 11.85 bv 7.87..

8.05 by 15.85 by 7.84..

11.73 by 11.98 bv 7.84..

3.75 by 11.80 by 7.94..

8.06 by 15.9 by 7.85..

11.78 by 11.87 bv 7.65..

in. 1.00

0. 64

1.37

2. 25

1. 26

0. 94

1. 24

0. 90 1.40

1. 28 1.35 1.22 0.92

1.24 1.66

0. 92

1.24

1.77

A

BD

D

CC

cCD

D

D

D

CD

E

CD

E

Percent

37

37

4322

26

33

26

334544

45

44

33

43

42

334342

lb/unit 24.8

34.0

lb/unit 24.6 33.4

4.3.3 61.4

16.8

16.4 16.4

16.6 33.3

40.0

33.6

40.3

17.9 42,0

44.

1

16.6 42.5

44.0

Ib/p

124.6

130.0

Percent

10.6 30.0

Percent

8.7

6.5

Iblfe 10.8 8.4

»/in.2 500 860

1, 760 2,975

810 800

1, 2.50

1, 020

540

755 605

1,420

1,310

1, 185 930

1,040

1,300 940

lAand 2A.

.3 A. Ul. U2.

4A. 4B.

.5A. 5B. 6A. 6B and 7B. 8A.

8B. 9B.

9B.

9A.

lOB. lOA.

lOB.

CU2 ...do SH4

SP4 SH5

SP5 SH6

SP6 SH8

SP8

SP9-1 SP9-2 SV9

SP1I>-1_... SP10-2..._ SVIO

Siliceous.. ...do ...do

...do

...do ...do

...do

...do

...do ...do

...do

...do

...do ...do

Vibration.. Dry tamp..

Vibration.. Dry tamp..

Vibration.. Dry tamp..

Vibration.. Dry tamp..

do

do

do

do

dodo

17.1 16.6

16.6

16.8 33.8

40.6 33.8

41.

1

18.1 42.6

44. 5 16.9 43.2

44.4

113.7

117.3

112.6 119.7

108. 7 122.3

114. 7 99.2

127.

1

127.2

12.3.9 118. 126.7

122.3

17.2

10.9

12.

1

11.9

10. 18.5

4. 5 8.6

2.3.5 19.8 10.9

17.7

17.9

10. 6

10.5

10.5

1.3. 5 9.3

14.8 8.5

13. 3 20.2

7.3

7.

1

8.4

9.8

7.3 8.9

11.8

12.3

I.5.2

II. 2

16.0

10.4

15. 2 20.0

9.3

9.0

10.4

11. 7 9.3

10.9

1 The designs of the units, in cutaway sections, are indicated in figure 1, p. 2.

2 All tests were made in accordance with Standard methods of sampling and testing concrete masonry units, ASTM Designation: C 140-39.

3 The moisture contents were determined at approximately the same time that the compressive strength tests were made. They are expressed as percentages

of the total absorptions.

(c) Molding and Curing

The units were molded by the "dry tamp" or the "vibration" process as indicated in table 2. All of those made with calcareous aggregates and

two lots of units made with siliceous aggregates,

SV9 and SVlO, were cured 12 to 14 hours in

moist rooms or wet-steam tunnels and then stored

in the open stockyard at the plant until shipped

to the National Bureau of Standards for test.

2. Mortar and Plaster

The mortar for all of the walls except Ul and

U2 consisted of one part of portland cement, one

part of hj^lrated lime and six parts of sand, by

volume. The mortar for walls Ul and U2 consisted of one part of portland cement, ^Koo part of hydrated lime, and 3 parts of sand, by volume.

Proper proportions were actuall}^ obtained by

weight, assuming that portland cement weighs 94

Ib/ft^ hydrated lime 40 Ib/ft^, and loose, damp

sand after drying weighs 80 Ib/ft^ The portland

cement and Iwdrated lime were of well-knowoi

brands obtained from local dealers. The sand for the walls tested at the National Bm-eau of Standards was Potomac River building sand, 95 percent

of which was a mixtm'e of siliceous minerals and

the remaining 5 percent a mixture of mica, calcite,

pyroxenes, and feldspar.

The plaster was sisal-fibered gypsum obtained

from local dealers. One part of the gypsum

plaster was mixed with three parts of sand, b}'

weight.

3

classed as calcareous. Those for walls 4 to 10,

inclusive, consisted of 90 to 95 percent quartz,

with small percentages of muscovite mica, feld- spar, and clay, and are classed as siliceous.

(b) Proportioning

The calcareous sand and gravel aggregates from

sources E and U were graded and recombined to give fineness moduli of 3.50 and 3.87, respectively.

The siliceous aggregates from source V were

graded and recombined to give a fineness modulus

of 3.87. The fineness moduli of the siliceous

aggregates from the other two sources P and H

were 2.62 and 2.70, respectively.

The cement-aggregate ratio for the 4-in. units

designated CEl was approximate!}^ 1:12 and for

the 4-in. units designated CE3, 1:9. For the 8-in. units made with calcareous aggregates CUl and

CU2 the ratios -were appro.ximately 1:7 and 1:6,

respectively. All of the units made with calcare- ous aggregates met the compressive strength re- quirement of the standard specifications.* The ce- ment-aggregate ratio for units made with siliceous

aggregates from source P was between 1:5 and

1:6 and for those from sources H and V, 1:7. All of the units, except the 8-in. units from source H, had the compressive strengths required by the

standard specifications.

* Standard specifications for hollow load-bearing concrete masonrv units, ASTM designation: C 90-44, and Standard specifications for hollow nonload-bearing concrete masonry units, ASTM designation: C 129-39.
3. Tests

Units representative of each design and kind of

aggregate were tested for compressive strength

and absorption, in accordance with Standard

methods of samphng and testing concrete masonry

units, ASTM designation: C 140-39. The results are given in table 2. The time of set, consistency, and tensUe strength

of the gypsum plasters were determined in accord- ance with Standard methods of testing gypsum

and gypsum products, ASTM designation: C 26-

33. The results are given in table 3. Table 3 also gives the compressive strengths of

the mortars and sanded plasters as determined

with 2-in. cubes, which had been seasoned in locations adjacent to the walls for which they were

used.

Table 3. Results of tests of mortar and plaster

Test walls in which mortsr and plaster

VV C/ L10C*J,

Mortar i Plaster

Compressive strength 2

Consist- ency 3

± II lie ul seta

Tensile strength s (neat)

IViix, dry

weight

proporCompresstrength ,3

lA

lb/in.'655

691 351 533

574 985

499

921 657

hr lUj t/L, 11)1ill 2 2A3A

Qo HO 1 .0 000

5A and 5B-.. . 6A and 6B

48 im 345 1:3 433 8A and 8B 9A and 9B

48 13H 345 1:3 512 lOA and 10B__. 50 15 230 1:3 434

1 The mortar consisted of 1 part of Portland cement to 1 part of hydrated

lime to 6 parts of sand, by volume.

' The compressive strengths of the mortar and plaster were obtained from

tests of three 2-in. cubes of each batch and were determined after they were

cured 28 days in locations adjacent to the partitions.

3 The times of set, consistencies, and tensile strengths of the plasters were

determined in accordance with Standard methods of testing gypsum products, ASTM designation: C 26-33.

1. Construction

The types of construction are indicated in figure

All of the 4- and 8-in. walls were built of 4-

III. Test Walls

and 8-in. units laid with cells vertical in common

bond. One section of each of the two 12-in. walls was built of units 12 in. thick laid in common bond

WALLS 1,2 WALL 3 WALLS 4,5

WALLS UI.U2,6,7. 8 WALLS 9A. lOB

Figure 2. Construction details of test walls. WALLS 9B.I0A
Figure 3. Unexposed side of load-bearing wall, 10, after

fire exposure of 3 hr 55 min on the opposite side. The test frame, the hydraulic jacks for loading the wall, and the asbestos pads over the thermocouples are shown. and the other section of each wall of 4- and 8-in. units laid in combination, as indicated in figure 2. The 10-in. wall was the cavity type and consisted

of two 4-in. walls spaced 2 in. apart, tied together

at points 24 in. apart in alternate courses. The

ties were of %6-in. steel wire bent to a 3%- by 6-in. rectangle with ends butted (not welded) at the

center of one short side.

2. Size

The walls tested at the National Bureau of

Standards were built in fu-eproofed frames of

20-in. 140-lb steel-ghder beams, bolted or riveted

at the corners, with openings for test specimens

16 ft long and 8 to 11 ft high. The walls were

built in two sections, each 8 ft long, bonded

together along the vertical center line except when

it was desired to load each section independently.

The walls tested at the Underwiters' Laboratories were built as single units in similar frames having

openings approximately 10 ft long and 11 ft liigh.

3, Restraint and Loading

The nonload-bearing walls were built solidly

within the frames to give a condition of restraint

representative of that at the borders of partitions

in buildings. The load-bearing walls were built

in frames equipped with hydraulic jacks, figures

3 and 4, so that loads could be applied throughout

the fire-endurance tests. They were centered on

8-ft loading beams resting on the pistons of the

hydraulic jacks, and were bedded with mortar

against the frames at the top. A clearance of

approximately 1 in. was left at each end of the

walls. Similar clearances were left between the

two sections of the load-bearing walls. The spaces were filled with loosely packed mineral wool, and

the two sections of wall were loaded independently

during the fire-endurance tests.

4. Workmanship

The walls were built and plastered by skilled

craftsmen working under contract. The workmanship was representative of local commercial

jobs.

Full horizontal mortar beds were used for the

4-in. walls, including the 4-in. wythes of the

cavity-type walls. Only the face shells of the

units in the 8- and 12-in. walls were bedded. The

vertical mortar joints were formed with mortar

applied to the outside edges of the units before

they were shoved into place. No attempt was made to point the joints in the walls which were

to be plastered. However, the walls that were

to be tested without plaster finish were carefully

pointed.

5. Finish

Some of the walls were finished with 1 : 3 sanded

gypsum plaster on one or both sides. Both the

scratch and brown coats were applied the same

day and given a float finish. The usual white-coat

finish was omitted. The total thickness of the

plaster was }^ in. Wood baseboards, nailed to wood plugs set in the masonry, were applied on

both sides of the plastered walls.

6. Storing and Aging

After the mortar or plaster had taken its initial

set, the frames containing the walls were moved

to storage tracks for seasoning for 1 month or more.

5
LONGITUDINAL SECTION HALF ELEVATION

Figure 4. Wall-testing furnace.

A, fui'nace chamber; B, burners; C, thermocouple protection tubes; D, pit for debris; E, mica-glazed observation windows; F, auxiliary aii' inlets; G, flue outlets and dampers; H, firebrick furnace lining; I, reinforced concrete furnace shell; K, gas cocks; L, gas control valve; M, ladders and platforms to upper obser- vation windows; N, movable flreproofed test frame; O, loading beams; P, hydraulic loading jacks; Q, load-bearing test wall; R, nonload-bearing test partition; T, asbestos pads covering thermocouples on unexposed surface of test wall.

IV. Method of Testing and Equipment

The fii'e tests were conducted in accordance

with the Standard methods of fire tests of building

construction and materials of the American

Standards Association, ASA No. A2-1934, (ASTM

designation: C19-33), except that the 16-ft walls were built in two 8-ft sections.

1. Wall-Testing Furnace

The furnace used for the

reinforced concrete and

tests was

lined with fire built

brick

of

to form a combustion chamber 2}^ ft deep and 16 ft long. The chamber extends 6 ft below the bottom

of the wall so that debris from the test specimen

does not obstruct the burners. The details of the

construction of the furnace are shown in figure 4. The walls were exposed on one side to fires that were controlled to give average indicated furnace

temperatures of approximately 1,000° F at 5 min,

1,300° F at 10 min, 1,550° F at 30 min, 1,700° F

at 1 hr, 1,850° F at 2 hr, 2,000° F at 4 hr, and

2,300° F at 8 hr or over. The test fire was produced by 92 gas burners

(B, fig. 4) controlled with /4-in. gas cocks, K, on

each burner and also with one larger valve, L, on

6 .
tlie main gas supply. The burners were of the

induction type with venturi mixing tubes, part of the air for combustion being drawn in around the

gas jet. Additional air was supplied to the combustion chamber through six 4-in. diameter inlets, F. The natural flow through these inlets was

accelerated by means of jets of compressed air. The fire exposure was continued in each test until one of the following criteria that limit the

fire resistance was obtained: (a) Fire damage

sufficient to allow the passage of flame or gas hot

enough to ignite cotton waste on the unexposed

side, (6) failure under the applied load, or (c) transmission of heat through the wall sufficient to

raise the average temperature on its unexposed

surface by 250 deg F or by 325 deg F at any

thermocouple location.

2. Temperature Measurements

All of the temperatures were measured with

chromel-alumel thermocouples at 5- to 10-min

intervals. The temperatures in the furnace were measured with nine 18-gage thermocouples, C,

figure 4. These thermocouples with their leads

within porcelain insulators were protected by

/4-in. wrought-iron pipes, sealed at one end. The

temperatures in the cells were measured with

18-gage thermocouples insulated with asbestos

sleeving. The temperatures on the unexposed

surface of the walls were measured with 22-gage

thermocouples, the leads of which were insulated

with asbestos sleeving except near the junctions.

The leads were coiled under flexible, oven-dry,

felted asbestos pads, 6 in. square and 0.4 in. thick,

held firmly against the partition. Extra thermocouples and a supply of dry cotton waste were

provided for possible use over cracks or at other

places on the surface of the walls where high

temperatures developed. The arrangement of

the thermocouples on the surface of a wall is shown

in figures 3 and 6. The leads from all of the thermocouples were

assembled in an insulated junction box, from

which a compensating thermocouple was con- nected to a cold junction maintained at the

temperature of melting ice. The ends of the

alumel and cbromel lead wires in the insulated

junction box were connected to tlie copper wii'es of a lead-sheathed cable leading to selector switches

in the instrument room. '^^I'hese switches were

connected to portable potentiometers for measuring the electromotive force of the thermocouples.

The readings of the potentiometers were subsequently converted to degrees F.

3. Deflection Measurements

The deflections were measured during the tests at nine locations on the unexposed surface of the

walls. They were obtained by measuring the

distance from the surface of the wall to three

weighted wires fastened to the top of the test frame and extending downward in front of and a few inches from the test wall. One of the wires was opposite the vertical center line of the test specimen and one was opposite the quarter points on each side of the center line.

4. Hose- Stream Test

Walls that withstand a fire-endurance test of

1 hr or more are required by standard test specifications to be subjected to a hose-stream test. This test is regularly made after subjecting a duplicate wall to a fire exposure of a duration

equal to half of the desired fire-resistance rating

but for not more than 1 hr. It is permissible,

however, to apply the hose stream to a wall

immediately after the fire-endurance test. This

optional procedure was used for the three fire- endurance and hose-stream tests included in this

series. The water for the hose-stream test was delivered

through a 2}'^-in. cotton, rubber-lined, fire hose

and discharged through a National Standard

playpipe equipped with a 1/g-in. discharge tip.

The tip of the playpipe was stationed 19 ft in front of the fire-exposed side, that is, 20 ft less

1 ft for the upward inclination of the hose stream. The water was discharged at pressures of 30 or 45 Ib/in.^ as required by the test methods. The

pressures were measured by means of a gage con- nected to the base of the playpipe, and were

regulated by a valve in the supply line.

V. Results

The results of the fire-endurance and hosestream tests are given in table 4 and in the logs of the individual tests.

1. Log of Tests

The log of tests gives the description of the

walls, the important observations that were made

during each test, the duration of the tests, the

factors which determined the fire endurance of

each wall, and the results of the hose-stream tests. Reference is made to figure 5 showing the deflections, toward ( +) and away ( — ) from the flre, at the center of the walls; to flgures 6 to 8, showing

the condition of some of the walls after test; and

to figures 9 to 14, giving the temperatures of the

furnace and the test walls. Test 1.—Four-inch unplastered nonload-bearing partition; calcareous-aggregate concrete units,

CEl, 37 percent of cell area, in section A. (The

results of the test with section B are not

included in this report.)

After 2 min of fire exposure, cracking sounds, whicli may have been caused by tiie craeliing of the webs of the

units, were heard. At 7 min, diagonal cracks across the bottom corners appeared. At 1554 min, similar cracks

across the top corners appeared. At 19 min, the widening

of the diagonal crack at the bottom of the partition indi- cated the approach of failure that occurred at 20}i min.

The failure consisted of the collapse of the lower portion

of the partition.

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0 1 2 3 4 5 6 TIME IN HOURS FiGUKE 5. Lateral deflections at centers of gravel-aggregate concrete masonry test walls. The curves w ithout suction designations A or B represent values obtained at the center of the combined wall. Tlie positive (+ ) values represent deflections toward the fire.

The fire endurance was limited to 20 niin by the collapse

of the partition. The deflection and temperature curves

are given in figures 5 and 9. Test 2.—Four-inch nonload-bearing plastered

partition; calcareous-aggregate concrete units,

CE2, 37 percent of cell area, in section A. (The

results of the test with section B are not included

in this report.) At 25 rain, fine diagonal cracks extending across the

corners of the unexposed side appeared. At 30 min, steam

began to issue at the borders of the wall and wet spots soon appeared on the unexposed surface, diminishing in size at 1 hr 5 min. At approximately 1 hr 25 min, horizontal cracks appeared in the unexposed side plaster near the top

and bottom of the partition. The gas was turned off at

1 hr 55 min. The fire endurance of the partition was limited by an

average temperature rise of 250 deg F on the unexposed

surface at 1 hr 51 min. The deflection and temperature

curves are given in figures 5 and 9. The partition was subjected to the hose stream at a

pressure of 30 lb/in. ^ for V/i min for each 100 ft^ of exposed

area. The hose stream washed off most of the plaster

and slightly pitted the surface of some of the units. As

no water passed through the wall, it met the requirements

of the hose-stream test. Test Ul .—Eight-inch unplastered load-bearing

wall; 80-lb/in.2 load; calcareous-aggregate concrete units, CUl 43 percent of cell area. (This was one of the walls tested at Chicago by the

Underwriters' Laboratories.)

Cracking sounds, accompanied by the formation of vertical cracks extending from the top to the bottom of the unexposed side of the wall, were heard intermittently

during the first 40 min. The four most prominent cracks appeared at 1, 2, 13, and 60 min near the midlength of the

wall. Other cracks near the ends of the wall followed

the vertical and horizontal mortar joints. The most

prominent of the vertical cracks had opened to a maximum

of approximately in. at 1 hr 10 min. At 21 min, the mortar in one of the exposed joints near the top of the wall

spalled. Steam issued from the cracks after 20 min and

during the remainder of the first hour of the test. Some

Figure 6. Unexposed side of Jf-in. unplastered nonloadbearing wall 1 after fire-endurance test.

9
of the steam condensed at the surface of the wall to form wet spots that disappeared at 1 hr 45 min. The gas was

turned off at 2 hr 16 min.

The fire endurance of the wall was limited by an average temperature rise of 250 deg F at 2 hr 14 min. The deflection and temperature curves are given in figures 5 and 10. The wall was subjected to the hose stream at a nozzle pressure of 30 lb/in. ^ for 2^-^ min for each 100 ft- of exposed

area. The surface of the exposed shells became eroded to a depth of }4 to % in. The hose stream washed out some

of the mortar from the joints but did not pass through the

wall. The applied load, 80 lb/in. 2, was carried throughout

the tests and doubled after the wall had cooled, without

indications of distress. The load was subseciuently

increased until failure occurred at approximately 297

lb/in. 2 The wall met the requirements of the hose-stream

test.Test U2.—Eight-inch unplasterecl load-bearing

wall; 175-lb/in.^ load; calcareous-aggregate concrete units, CU2, 22 percent of cell area. (This was one of the walls tested at Chicago by the

Underwriters' Laboratories.)

Cracking sounds were heard during the first 5 to 11 min

of the test. Vertical cracks, generally extending along

the vertical mortar joints and across the intervening units, appeared in the unexposed side during this time. Some

of the cracks opened to a maximum of %2 in. during the

early part of the test and closed somewhat after 40 min.

Steam issuing at the cracks condensed on the wall surface

to form wet spots. These spots were first noted at 25

min. They increased in number and size during the first hour of the test and then gradually disappeared. The gas was turned off at 4 hr. The fire endurance of the wall was limited by an average temperature rise of 250 deg F on the unexposed surface at

3 hr 57H min. The deflection and temperature curves

are given in figures 5 and 10. The wall was subjected to the hose stream at a pressure

of 45 lb/in. 2 for 5 min for each 100 ft- of exposed area. The exposed shells were eroded to a depth of J-^ to ^}io in. by the hose stream, which washed out some of the mortar from the joints but did not pass through the wall. The

applied load, 175 lb/in. 2, was carried throughout the tests. After the test wall had cooled for approximately 20 hr, the amount of the load was gradually increased. When a

load of 327 lb/in. ^ was reached, some of the mortar in the

joints in the upper part of the wall appeared to be crushing.

When it reached 343 lb/in. 2, or 7 lb less than twice the load applied during the tests, the wall failed. Considering that the hose-stream test was made on the wall after the fire- endurance test rather than on a duplicate specimen after a fire exposure of 1 hr, the results indicate that the construction would have met the hose-stream test require- ments had a duplicate specimen been tested. Test 3.—Ten-inch unplastered cavity-type wall

of two 4-in. wythes spaced 2 in. apart and tied

together with metal ties 24 in. apart in alternate

horizontal joints; 80-lb/in.- load; calcareousaggregate concrete units, CE3, 37 percent of cell area, in section A. (The test results for section B

are not included in this report.) At 5 min, cracking sounds were heard. At 15 min, a

slight amount of spalling from the top portion of the exposed surface was noted. At 28 min, a fine vertical crack, starting near the middle and extending almost to the top of the unexposed side of the wall, appeared. This

crack became pronounced during the next 10 minutes.

Wet spots appeared on the upi^er part of the unexposed

surface after approximately 45 min. At 1 hr 16 min, the

wall failed under the applied load and fell toward the fire. The fire endurance of the wall was limited by its failure under load at 1 hr 16 min. The deflection and temperature curves are given in figures 5 and 9.

Test 4.—Four-inch implastered nonload-bearing partition; siliceous-aggregate concrete units,

.SH4, 26 percent of cell area, in section A; sUiceousaggregate concrete units, SP4, 33 percent of cell area, in section B.

At 5 min, a fine diagonal crack appeared across the

lower corner of the unexposed surface of the partition. A

similar crack across the other lower corner appeared 2 min

later. At 10 min, the deflection toward the fire was pro- nounced. At 12 min, the diagonal cracks at the lower

corners had opened. At 17 min, the partition collapsed,

falling toward the fire. The fire endurance of the partition was limited by its collapse at 17 min. The deflection and temperature curves

are given in figures 5 and 11. Test 5.—Four-inch plastered nonload-bearing

partition; siliceous-aggregate concrete units, SH5,

26 percent of cell area, in section A; siliceousaggregate concrete units, SP5, 33 percent of cell area, in section B.

Horizontal cracks extending the length of the test partition, 3^2, 5y2, and 9% ft from the lower edge of the unexposed side plaster, appeared at 5, 10, and 19 min,

respectively. At 16 min, wet spots outlining the mortar

joints, began to show in the \mexposed plaster. At 25

min, steam was issuing at cracks. At 35 min, some of the

plaster near the middle of the unexposed side loosened but

did not fall. At 585-4 min, due to the restraint, some of the units at midheight and near one end of the partition

failed by crushing. This condition is shown in figures

7 and 8. The fire endurance of the partition was limited by its structural failure at 58}-; min. The deflection and temperature curves are given in flgures 5 and 11. Test 6.—Eight-inch unplastered load-bearing

wall; 80-lb/in.^ load; sUiceous-aggregate concrete

units, SH6, 45 percent of cell area, in section A;

siliceous-aggregate concrete units, SP6, 44 percent

of cell area, in section B.

During the period from 6 to 10 min after the start of the test vertical cracks formed, first uear the middle of each of the two sections and then near the ends. These

cracks extended both upward and downward from midheight to near the top and bottom of the wall. At 12 min,

section A collapsed without warning. The webs of the

units had broken allowing the exposed portion of the wall

to fall toward the fire and the unexposed portion to fall outward. The fire exposure on section B could not be

continued. The fire endurance of section A of the wall was limited to 12 min by its failure under load; that of section B was

not determined. The deflection and temperature curves

are given in figures 5 and 12. Test 7.—Eight-inch unjolastered load-bearing

wall; 80-lb/in.- load; siliceous-aggregate cdncrete

units, SP6, having 44 percent of cell area, in section B. This was a retest of section B remaining from test 6. At 8 min, the cracks formed during test 6 began to reappear. At 18 min, one of the exposed shells spalled

and fell. At 21 min, the wall collapsed in the same manner

as section A of the previous test. The fire endurance of this wall was limited in its retest to 21 min by its failure under load. This result may not be fully representative, considering the previous exposure

in test 6. The deflection and temperature curve are given

in figures 5 and 12. Test 8.—Eight-inch plastered load-bearing wall;

80-lb/in.^ load; siliceous-aggregate concrete imits,

10
SH8, 45 percent of cell area, in section A; siliceousaggregate concrete units, SP8, 44 percent of cell area, in section B.

Vertical cracks extending the full height of the wall appeared in the unexposed side of section A during the

period from to IG min after the start of the fire exposure. At 20 min, steam began to issue from the cracks and wet

spots showed over the mortar joints in the unexposed

plaster. At 32 min, section A of the wall failed under load, and some of the plaster and shells fell from its unexposed

side. At iO}'2 min, the remaining portion of section A

collapsed, making it impossible to continue the test of section B. The fire endurance of section A of the wall was limited

to 32 min by its failure under load. Section B of the wall was not subjected to a retest. It was dismantled and inspected for damage to the individual

units. They appeared to be relatively free from fire damage, showing that the plaster had protected them

during the fire exposure. The deflection and temperature

curves are given in figures 5 and 12. Test 9.—Twelve-inch unplastered load-bearing

wall; 80-lb/in.^ load; 12-in. siliceous-aggregate concrete units, SV9, 42 percent of cell area, in

section A; 8-in. units, SP9-2, having 43 percent

of cell area with 4-in. units, SP9-1, having 33

percent of cell area (laid as shown in fig. 2) and

made with sUiceous-aggregates, in section B.

After approximately 45 min of fire exposure, a vertical crack extending the full height of the wall appeared near

the middle of the unexposed sides of each section. At

26 min, section A failed under the applied load but did not

fall from the frame. As the partially crushed masonry of section A remained in place, it was possible to continue the

test of section B. At 56 min, steam was issuing from the

wall and wet spots were forming in the unexposed plaster

of section B. At 3 hr 8 min, section A collapsed, so that

the test on section B had to be discontinued.

The fire endurance of section A of the 12-iri. units was

limited to 26 min by its failure under load. The fire endurance of section B of 8- and 4-in. units was not

reached, but it can be taken as exceeding 3 hr and 8 min.

The deflection and temperature curves are given in figures 5 and 13. Test 10.—Twelve-inch unplastered load-bearing

wall; 80-lb/in.^ load; 8-in. units, SPlO-2, having

43 percent of cell area, with 4-in. units, SPlO-1,

having 33 percent of cell area (laid as shown in fig. 2) and made with siliceous-aggregates, in section A

;

12-in. siliceous-aggregate concrete units, SVlO, 42

percent of cell area and plastered on both sides, in

section B.

At 15 min, a vertical crack extending from the bottom

to the midheight of the wall appeared in the middle of the unexposed side of section A. During the period from 22

to 44 min, vertical cracks appeared in the plaster on the unexposed side of section B. At 44 min, wet spots began

to appear in the plaster of section B, and at 1 hr 3 min,

horizontal cracks were observed. The cracks gradually

widened as the test progressed, one of those in the plaster

opening to a width of approximately in. At 1 hr 43

min, the cracks in the unplastered section A were wider

than those of the plastered section B. Additional fire effects observed during the remainder of the test were the growth and widening of the cracks. The gas was turned

off at 6 hr 16 min.

The fire endurance of the unplastered section A, with a

thickness of two units, was limited to 5 hr 33 min by a

temperature rise of 325 deg F at one place on the unexposed

surface. The fire resistance of the plastered section B, with a thickness of one unit, was limited to 6 hr 5 min by

a temperature rise of 325 deg F at one place on the unexposed

surface. The condition of the unexposed side of the wall, after a fire exposure of 3 hr 35 min on the opposite side, is shown in figure 3. Deflection and temperature curves

are given in figures 5 and 14.

VI. Discussion of Results

The limit of the fire endurance of walls and

partitions maj be determined (a) by structural

damage sufficient to allow the passage of flames

or gases hot enough to ignite cotton Avaste, (b) by

an average temperature rise on the unexposed

surface of 250 deg F or a rise of 325 deg F above the

initial temperature at any point, or (c) in the case

of a load-bearing wall, by failure under load.

1. Effect of Type of Aggregate

As indicated in these and previous tests reported

in BjMS117 (see footnotes 1 and 2), susceptibility

of individual concrete units to spalling or cracking on fire exposure is dependent mainly upon the

type of aggregate with which the unit is made.

Those made with siliceous aggregates consisting

largely of- siliceous minerals, such as quartz and

chert, are subject to decided damage. Siliceous

minerals also undergo abrupt volume changes at temperatures as low as 410° F (210° C) for chert

and at about 1,063° F (573° C) for quartz, the

inversion point from the alpha to the beta form.

The high stresses resulting from unequal expansion

in the different parts of the units made with

siliceous aggregates generally result in the rupture

of the webs rather than the spalling or flaking of

the shells.

The webs of units made with calcareous aggregates are less likely to crack than those made with

siliceous aggregates due to the lower expansion of

the concrete. Under fire exposure, calcareous

aggregates undergo calcination, a process that

requires heat and produces a material that is a relative^ good insulator. This retards heat

transfer and consequently delays the occurrence

of high temperatures on the unexposed side of

the wall. The effect of type of aggregate on fire endurance

may be demonstrated with the results obtained

from walls 5 and 2. Wall 5, a plastered nonload-bearing partition of units made with sUiceous

aggregates, collapsed after 58^2 min of fu-e ex- posure. Wall 2, similar in construction to wall 5 except that the units were made with calcareous

aggregates, withstood the test for 1 hr 51 min, at which time an average temperature rise of 250 deg F

on the unexposed surface was reached.

2. Effect of Loading and Restraint on Type

of failure

Location of cracks and type of faUure are influ- enced by the restraint and the loading of the walls. Loaded walls that are not fixed at the vertical

edges take on a more or less continuous curvature

11
Figure 7. Exposed side of 4-in. -plastered nonload-bearing wall 5 after fire-endurance test.
from near the top to near the bottom edge. Since

the units of the restrained wall are bedded against

the restraining frame, the curvature of the

deflected wall does not extend over the whole area but is confined more nearly to an ellipse having

axes somewhat less than the dimensions of the

wall. The deflection of the units adjacent to this

elliptical area is restrained by contact with the

frame and, consequently, the units bounding the

ellipse are, in many cases, crushed or the shells on

the exposed side are loosened. This is illustrated

by the test of wall 5, a 4-in. plastered partition of units made with siliceous aggregate. (See figs. 7 and 8.) Vertical cracks that were more or less continuous on the central part of the unexposed side of the

loaded walls, but which did not show on the exposed

side, indicated vertical restraint and freedom for

lateral expansion in the central portion of the walls.

3. Effect of Strength of Unit

Indications are that the time to failure in the

fire test is affected by the strength of the units.

In the test of the 8-in. unplastered load-bearing

wall 6, section A, which was buUt of units from

source H having a compressive strength of 540

lb/in. ^, failed at 12 min; section B, which was built

of units from source P having a compressive

strength of 755 Ib/in.^, was allowed to cool and was subjected to a retest for 21 min before failure

took place. In a similar 8-in. plastered loadbearing wall 8, section A, which was built of units

from source H having a compressive strength of

605 lb/in. ^, faUed at 32 min; section B, which was

built of units from source P having a compressive

strength of 1,420 Ib/in.^, continued to carry the

load after failure of section A, and the individual

units were found to be relatively free from damage.

4. Effect of Plaster

The importance of plaster in increasing fire endurance as established by temperature rise on

the unexposed surface was not determined in

these tests. Only the unplastered 8-in. loadbearing walls of units made with calcareous

aggregates and the two-unit 12-in. unplastered

wall of units with siliceous aggregate were able to withstand the fire exposure until the limiting

temperature rise on the unexposed surface was

reached. All of the other unplastered walls in

this series failed under load or collapsed early

during the fire exposure. The plastered walls

withstood longer fire exposures than the similar

unplastered walls before failure under load or

collapse took place or before the limiting temperature rise on the unexposed surfaces was reached.

The effectiveness of plaster in increasing the

stability of walls under fire exposure is shown by

the test results from the 4-in. unplastered nonload-bearing wall 1, and the 4-in. plastered nonload-bearing wall 2, which were built of units

made with calcareous aggregate and which gave

fire-endurance values of 20 min and 1 hr 51 min.

respectively. This is also shown by the test results from the 4-in. unplastered nonload-bearing

wall 4, and the 4-in. plastered nonload-bearing

wall 5, which were built of units made with sili- ceous aggregate, and which gave fire-endurance

values of 17 min and 58^2 min, respectively.

Similar comparisons may be made from the results with the 8-ia. unplastered load-bearing wall 6A

and the 8-in. plastered load-bearing wall 8A, which

were built of units made with siliceous aggregates

and which gave fire-endurance values of 12 min

and 32 min, respectively. The 12-in. unplastered

load-bearing wall 9A and the 12-in. plastered loadbearing wall lOB, which were built of units made

with siliceous aggregate and which gave fire- endurance values of 26 min and 6 hr 5 min,

respectively, also show this comparison.

5. Performance of Cavity-Type Construction

The unplastered cavity-type or double wall 3B

built of two wythes of 4-in. units made with cal- careous aggregates failed under load at 1 hr 16

min. The single 4-in. restrained wall 1 of similar

units failed at 20 min. Failure of the exposed

4-in. wythe of the cavity-type wall was delayed

because its deflection was restrained by the ties into the unexposed part. Also, as this wall was

loaded and free at the vertical edges, it may not

have been subjected to as high stresses as probably were imposed on the restrained wall lA.

6. Effect of Combustible Framed-In Members

The time at which a limiting temperature rise of

325 deg F as an average or of 422 deg F at any

single location is reached at points approximately

4 in. from the unexposed surface or in the cell next

to the unexposed side will determine the fire-resist- ance values of walls with joists or other combustible members framed into the wall, unless an

earlier failure from some other cause takes place.^

The fire-resistance values for walls with combustible framed-in members are given in table 4. These

values are based on the assumption that the ends

of the joists in the walls are bedded in masonry

on the sides as well as on the bottom.

The 8-in. unplastered wall Ul, of units made of

calcareous aggregates, would have a fu-e resistance

of 56 min for the condition that would exist with

wood joists projecting 4 in. into the wall as compared with 2 hr 14 min with incombustible or no

bearing members framed in the wall. The singleunit 12-in. plastered bearing wall, section B of

wall 10, would have a fire resistance of 2 hi* 31 min

with combustible framed-in members as compared

with 6 hr 5 min with incombustible or no framedin members.

For the two-unit unplastered bearing wall,

section A of wall 10, with combustible members

framed into the 8-in. -thick units on the unexposed

side, the fire resistance would be 2 hr 28 min. It would be 3 hr 54 min with the combustible mem-

' standard methods of fire tests of building construction and materials, ASA No, A2.1-1942 (ASTM C 19-41), sec. 24b. 13
bers placed with ends between the 4-in. -thick units on the unexposed side, leaving a full thickness of an 8-in. unit between the end of the framed-in

member and the fire-exposed side. The fire resistance of walls with combustible members

framed into hollow units can be increased by

filling the units between, above, and below these

combustible members with masonry materials.^

7. Resistance to Hose- Stream Test

Only the walls of units made with calcareous

aggregates were subjected to the hose-stream test. The three walls to which the test was applied

showed good performance even though they were

subjected to a long fire exposure before the hose

stream was applied. All of the walls of units

made with siliceous aggregates faded in the fire- endurance tests after short fire exposures or were damaged so that a subsequent hose-stream test would have been misleading unless duplicate test specimens were used. However, it seemed fairly

assured that the two-unit 12-in. unplastered walls,

section B of wall 9 and section A of wall 10, and

the single-unit plastered 12-in. wall, section B of

wall 10, would have passed the hose-stream test after 1 hr of fire exposure, which is the maximum

required by the standard fire-test specifications

before the hose stream is applied.

The 10-in. cavity-type wall 3B, which had a fire

9 National Buieau of Standards BMS92, Fire resistance classifications of building constructions, p. 27.

endurance of 1 hr 16 min established by load

failure, apparently would have met the hosestream test requirements had a duplicate wall

been used and subjected to a fire exposure of half

of the duration of the fire-endurance test. At

that time, the deflection of the wall was 2)^ in. and

all units in the fire-exposed wythe, and their

shells, were in place.

The 4-in. plastered nonload-bearing wall 5, built of units made with siliceous aggregates,

faded near one end at 58^/2 min by the crushing

of individual units. This fire endurance can be

increased from 58/^ min to 59/2 min by correcting

for the high severity of the fire exposure.^ With

this correction and the usual tolerance allowance,

this wall would be considered as having a fire en- durance of 1 hr and be required to meet the hosestream test requirements. Although the deflec- tion at the center of the wall was approximately

5 in. just before failure occurred, it was only 1.2

in. at 30 min, which is the fire exposure re- quired when a duplicate specimen is used for the

hose-stream test. The margin of stability thereby

shown, taken together with the general experience

with hose-stream tests applied to masonry partitions, indicates that the hose-stream requirements probably would have been met after a 30-min fire exposure, although in the absence of a test this cannot be assured.

' ASTM Standard, E 119-47, sec. 5 (b).

VII. Summary

The fire-resistance values of the walls of gravelaggregate concrete masonry imits determined in the present series of tests are given in table 4. The table includes data from which the fire- resistance values for walls with combustible

framed-in members can be obtained.

The mineral composition of the aggregates in

the concrete units had a decided effect upon the

fire resistance of the walls. The walls of this series apparently included the upper and lower

range of performance attributable to the usual

types of natural aggregates. The pebble gravels

of the calcareous aggregates had approximately

80 percent of calcareous minerals, and the sand

had approximately 50 percent. The siliceous

aggregates consisted of 90 to 95 percent of quartz,

with small amounts of feldspar, mica, and clay.

The fire resistance of the 4-in. unplastered wall

of units made of calcareous aggregates was limited

by collapse of the wall at 20 min. A plastered

wall of the same size and type of units had a fire resistance of 1 hr 51 min, as determined by the

temperature rise on the unexposed surface. The

8-in. unplastered walls of units made with cal- careous aggregates, which had 43 and 22 percent

of cell area, developed fire-resistance values of 2 hr 14 min and 3 hr 57 min, respectively, as determined by an average temperature rise of 250 deg F

on their unexposed surfaces. The fire resistance

of the 10-in. cavity-type wall of two wythes of 4-in.

walls of units made with calcareous aggregates was

limited to 1 hr 16 min by high deflection and con- sequent failure under load.

The fire-resistance values of the 4- and 8-in. unplastered or plastered walls and the 12-in. single-unit unplastered walls of units made with

siliceous aggregates were limited by collapse of the

test specimen after excessive deflections or by

failure under load. The 12-in. plastered singleunit walls and the 12-in. unplastered two-unit

(4-in. and 8-in.) walls successfully carried the

applied load for extended fire exposures until specified limiting temperatures were reached on the

unexposed surfaces. The fire-resistance values limited by temperature rise on the unexposed surface of walls with

incombustible or no framed-in members are two

to three times those of walls with combustible

framed-in members, for which the values are determined by temperature rise within the wall

adjacent to or at the end of the combustible member.Acknowledgment is made to the National Concrete Masonry Association for manufacturing and

supplj'ing the 4-in. -thick concrete masonry units

made with calcareous aggregates, and to the

Underwriters' Laboratories for the use of data

from their tests of two 8-in. walls of units made

with calcareous aggregates.

14
2400 2300

2200 2100

2000

1900

1800

1700 1600

1500 1400

1300

1200

1100

1000 900

800

700 600 500

400

300

200

1000

TEST NO, 1

it >^ A

F MAX

'^^ IN

—f- n

r

, _

jc=i|i=]oc=nait=igc=ij

CALCAREOUS AGGREGATE 371 CELL AREA

UNIT DESIGN A

CONSTRUCTION DETAILS AND

THERMOCOUPLE LOCATIONS

wALL C 3LL APS ED

L- Amax 11

TEST NO. 2

Fu — < -

neFt"'-':

- cUR'J'-

-V

--

-

Fmin /A/

•J

3 O

1' 2

MIN

18

1 J_ I

.,h_,i 1 t 1

CALCAREOUS AGGREGATE 37% CELL AREA

UNIT DESIGN A CONSTRUCTION DETAILS AND

THERMOCOUPLE LOCATIONS AmAK^

L1M T- 250 "F RIS E

CALCAREOUS AGGREGATE 37% CELL AREA

UNIT DESIGN B CONSTRUCTION DETAILS AND THERMOCOUPLE LOCATIONS

I

I

I I I LOAD FAILURE

TIME IN HOURS Figure 9. T'emperatures in fire-endurance tests of 4-in. nonload-bearing walls 1 and 2 and 10-in. cavity-type load-bearing

wall 3 built of units made with calcareous aggregates. The solid line curves show the average temperatures and the broken line curves the ma.ximum and minimum temperatures at the locations indicated in the

construction sketches.

2400 2300

2200

2100

2000

1900

1800

1700 1600

1500

1400

1300

1200

1100 1000 900

800 700

600

500

400

300 200

1000

TEST NO. U-l

— a

o

R

^fERENCE

"cu WE —

I

3

k

ia

t

-f a

,

—if- MO0OOOOCi1

CALCAREOUS AOOREGATE mCELL AREA

UNIT DE3I0N D

CONSTRUCTION DETAILS AND THERMOCOUPLE LOCATIONS Cmax

-c- 325' F fl ISE IN CELL li L MI1 -2 50* F )ISE

1 X

TEST NQ U-2

C.F

( COR^t - %

a

3b

»

S

F

)oOoooOo(|]

i

CALCAREOUS AOOREOATE 22%CELL AREA

UNIT DESIGN D

CONSTRUCTION DETAILS AND THERMOCOUPLE LOCATIONS

29C "F Rl' E

-

3h<

I

TIME IN HOURS Figure 10. Temperatures in fire-endurance tests of 8-in. load-bearing walls Ul and U2 built of units made with calcareous

aggregates. The solid line curves show the average temperatures and the broken line curves the maximum temperatures at the locations indicated in the construction

sketches. 15
2400

2300

2200 2100

l_ 2000

CD 1900 I

2 1800

LlJ CC 1700 X

< 1600

U.CO 1500

LlI UJ 1400 O 1300

1200

1100

bJ 1000

CC3 900

I-< 800 ^ 700 2 600

Ijj 500

400

300

200

1000

TEST NO. 4

o _3

/

.'/

X

SECTION A n SECTION B

r

; \. 1

1

T

SILICEOUS AGORCOATE SILICEOUS AOSREOATE 26% CELL AREA ^^% CELL AREA

UNIT DESIGN C UNIT DESIGN C

CONSTRUCTION DETAILS AND

THERMOCOUPLE LOCATIONS

V APSfO _J As 8 MAX &e>B 1

TEST NO. 5

||

GAS

OFF

ft? -^-'^

- F MAXx-,4

-

n

/ -(-

\ll t

I' SECTION A SECTIONS

SILICEOUS AGGREGATE SILICEOUS AGGREGATE 2S% CELL AREA 33% CELL AREA

UNIT DESIGN C "NIT DESIGN C

CONSTRUCTION DETAILS AND

THERMOCOUPLE LOCATIONS

WA L CRUSHED A a 8 MA X

\

TIME IN HOURS Figure 11. Tem-jjeratures in fire-endurance tests of 4-in. nonload-bearing walls 4 and 5 built of units made with siliceous aggregates.

The, solid line curves show the average temperatures and the broken line curves the maximum and minimum temperatures at the locations indicatedlin the

construction sketches.

2400

2300

2200 2100 H

2000

LlI 1900 I

Z 1800

LlJ CC 1700 X

< 1600

If) 1500

bJ

UJ 1400

CCo 1300

LlI Q 1200 z 1100

LU 1000

(£

=) 900 ^ 800

CC3d 700

UJ 600

H- 500

400

300

200

1000

TEST NO 6

v1

)00000000000(1

SILICEOUS AGGREGATE A<^

SILICEOUS ^AGGREGATE 45% CELL AREA 44% CELL AREA

UNIT DESIGN D UNIT DESIGN 0

CONSTRUCTION DETAILS AND

THERMOCOUPLE LOCATIOMS

LOAD FAILURE J A > B MAX A»8 I I

- TEST NO 7

O

<

F MAX /

-4-

MIN P

-^)oooooooooooc-i

SLICEOUS AGGREGATE — 44% CELL AREA

UNIT DESIGN D

CONSTRUCTION DETAILS ~ AND

THERMOCOUPLE LOCATIONS

1 1 1 1 1 LOAD FAILURE -^sr," 1 1

TEST NO 8

O

T-

/|

T \>\~

FFmi N ^ 1

SECTION A 1^ SECTION B

)OOOOO0OOOOO(4

SILICEOUS AGGREGATE SILICEOUS AGGREGATE 45% CELL AREA 44% CELL AREA

UNIT DESIGN D UNIT DESIGN D

CONSTRUCTION DETAILS AND

THERMOCOUPLE LOCATIONS CI AX LOAD FAILURE -C A a 8 MAX AaB 1

1 1 1 O I 2 0 I 0 I 2 3 TIME IN HOURS FiGUEE 12. Tem'peratures in fire-endurance tests of 8-in. load-hearing walls 6, 7, and 8 built of units made with siliceous aggregates. The solid line curves show the average temperatures and the broken line curves the maximum and minimum temperatures at the locations indicated in the construction sketches. 16
2400

2300

2200

2 100 2000

1900

1800

1700

1600

1500 (/)

liJ lU 1400

OCO 1300

1200

1100 1000 900

600

700 600

500 400

300 200

1000

TEST NO 9

t

o

i?

F M*x -- ---- COBVE 1 F /

/ / CAuAX

-p y

-'- Fh N - SECTION A SECTION B 4

/

.1 f

1 CA •I 000( ]o4oo

-i

1

I ^CA /cB \

4

I /

—

Ahax SILICEOUS AGGREOATE / SILICEOUS AOGREGATe\

42 1 CELL AREA 33% CELL AREA 43% CELL AREA

UNIT DESIGN D UNIT DESIGN C UNIT DESIGN 0

(COURSES 2,4.6, ETCJ (COURSES l,3,S, ETU

CONSTRUCTION DETAILS AND THERMOCOUPLE LOCATIONS

/ /

-f-

/ A $/ /- /

/

/

7 51 —

4B

4B

Bh

+- HAN

1 /l 7

—-

8

1

Figure 13.

2 TIME IN HOURS

Temperatures in fire-endurance tests of 12-in. load-hearing wall 9 built of units made with siliceous aggregates. The solid line curves show the average temperatures and the broken line curves the maximum and minimum temperatures at the locations indicated in the

construction sketches.

2400

2300

2200 2100

2000

lU 1900 X

z 1800

UJ

cc 1700 X

< 1600

Ll

(D 1500

LU

Ld 1400

CCo 1300

LUo 1200 z 1100

IxJ 1000

CC

z> 900

1-< 800

cr3d 700

600

LU

1- 500

400

300

200

1000

/ SILICEOUS AGGREGATE \ SILICEOUS AGGREGATE 33%CELLAHEA 44%CELLAREA 42%CELLAREA

UNIT DESIGN C UNIT DESIGN 0 "NIT DESIGN E (COURSES 2,4,6 ETCJ (COURSES 1.3.5 ETC ) CONSTRUCTION DETAILS AND THERMOCOUPLE LOCATIONS

Figure 14.

2 3 4 5 TIME IN HOURS

Temperatures in fire-endurance tests of 12-in. load-bearing wall 10 built of units made with siliceous aggregates. The solid line curves shovir the average temperatures and the broken line curves the maximum and minimum temperatm'es at the locations indicated in the

construction sketches. Washington, April 24, 1950.

17

U. S. GOVERNMENT PRINTING OFFICE: I95I

BUILDING MATERIALS AND STRUCTURES REPORTS

[Continued from cover page ii] BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete-Block Wall Construction Sponsored by the National Concrete Masonry

Association 15^ BMS33 Plastic Calking Materials 15^ BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 15^ BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging * BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions With "Red Stripe" Lath Sponsored by The Weston Paper and Manufacturing Co 10^ BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors, Sponsored by Palisade Homes * BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co " 10^ BMS39 Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co 10^ BMS40 Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored by Knap America, Inc 15^ BMS41 Effect of Heating and Coohng on the Permeability of Masonry Walls * BMS42 Structural Properties of Wood-Frame Wall and Partition Constructions with "Celotex"

Insulating Boards Sponsored by The Celotex Corporation 15^ BMS43 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 15j5 BMS44 Surface Treatment of Steel Prior to Painting 10^ BMS45 Air Lifiltration Through Windows 15^ BMS46 Structural Properties of "Scott-Bilt" Prefabricated Sheet-Steel Constructions for Walls, Floors, and Roofs Sponsored by The Globe-Wernicke Co * BMS47 Structural Properties of Prefabricated Wood-Frame Constructions for Walls, Partitions and Floors Sponsored by American Houses, Inc 20^ BMS48 Structural Properties of "Precision-Built" Frame Wall and Partition Constructions

Sponsored by the Homasote Co 15^ BMS49 Metallic Roofing for Low-Cost House Construction 20fi BMS50 Stability of Fiber Building Boards as Determined by Accelerated Aging lOji BMS51 Structural Properties of "Tilecrete Tvpe A" Floor Construction Sponsored bv the

Tilecrete Co 1 lOfS BMS52 Effect of Ceihng Insulation Upon Summer Comfort 15^ BMS53 Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored bv the Munlock Engineering Co lOji BMS54 Effect of Soot on the Rating of an Oil-Fired Heating Boiler lOfS BMS55 Effects of Wetting and Drying on the Permeability of Masonry Walls 10^ BMS56 A Survey of Humidities in Residences 10^ BMS57 Roofing in the United States—Results of a Questionnaire * BMS58 Strength of Soft-Soldered Joints in Copper Tubing 10^ BMS59 Properties of Adhesives for Floor Coverings 15^ BMS60 Strength, Absorption, and Resistance to Laboratory Freezing and Thawing of Building

Bricks Produced in the United States 30^ BMS61 Structural Properties of Two Nonreinforced Monolithic Concrete Wall Constructions. _ lOjS BMS62 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by

the Portland Cement Association 10^ BMS63 Moisture Condensation in Building Walls 15^ BMS64 Solar Heating of Various Surfaces 10^ BMS65 Methods of Estimating Loads in Plumbing Systems 15^ BMS66 Plumbing Manual 35«i BMS67 Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for Walls, Partitions, Floor, and Roofs, Sponsored by Herman A. Mugler 15fi BMS68 Performance Test for Floor Coverings for Use in Low-Cost Housing: Part 3 20^ BMS69 Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 10^ BMS70 Asphalt-Prepared Roll Roofings and Shingles 20ji BMS71 Fire Tests of Wood- and Metal-Framed Partitions 20^ BMS72 Structural Properties of "Precision-Built, Jr." Prefabricated Wood-Frame Wall

Construction Sponsored by the Homasote Co lOfS BMS73 Indentation Characteristics of Floor Coverings 10^ BMS74 Structural and Heat-Transfer Properties of "U. S. S. Panelbilt" Prefabricated SheetSteel Constructions for Walls, Partitions, and Roofs Sponsored bv the Tennessee

Coal, Iron & Railroad Co 20i

BMS75 Survey of Roofing Materials in the North Central States 15fS BMS76 Effect of Outdoor Exposure on the Water Permeability of Masonry Walls 15^ BMS77 Properties and Performance of Fiber Tile Boards " lOfS BMS78 Structural, Heat-Transfer, and Water-Permeability Properties of Five Earth-Wall

Constructions 25^

BMS79 Water-Distributing Systems for Buildings 20^ BMS80 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 4 15^ BMS81 Field Inspectors' Check List for Building Constructions (cloth cover, 5 x 7>.^ inches) 30fi •Out of print. [List continued on cover page iv]
BUILDING MATERIALS AND STRUCTURES REPORTS

BMS82

BMS83

BMS84

BMS85

BMS86

BMS87

BMS88

BMS89

BMS90

BMS91

BMS92

BMS93

BMS94

BMS95

BMS96

BMS97

BMS98

BMS99

BMSlOO

BMSlOl

BMS102

BMS103

BMS104

BMS105

BMS106

BMS107

BMS108

BMS109

BMSUO

BMSlll

BMS112

BMS113

BMS114

BMS115

BMS116

BMS117

BMS118

BMS119

BMS120

BMS121

•Out of print.

[Continued from cover page m]

Water Permeability of Walls Built of Masonry Units 25^ Strength of Sleeve Joints in Copper Tubing Made With Various Lead-Base Solders 15^ Survey of Roofing Materials in the South Central States i5jii Dimensional Changes of Floor Coverings With Changes in Relative Humidity and

Temperature 10^

Structural, Heat-Transfer, and Water-Permeability Properties of "Speedbrik" Wall

Construction Sponsored by the General Shale Products Corporation 15f, A Method for Developing Specifications for Building Construction—Report of Subcommittee on Specifications of the Central Housing Committee on Research,

Design, and Construction ' 15^4 Recommended Building Code Requirements for New Dwelling Construction With

Special Reference to War Housing * Structural Properties of "Precision-Built, Jr." (Second Construction) Prefabricated

Wood-Frame Wall Construction Sponsored by the Homasote Co 15^ Structural Properties of "PHC" Prefabricated Wood-Frame Constructions for Walls,

Floors, and Roofs Sponsored by the PHC Housing Corporation 15^; A Glossary of Housing Terms 15^ Fire-Resistance Classifications of Building Constructions 30^ Accumulation of Moisture in Walls of Frame Construction During Winter Exposure 10^ Water Permeability and Weathering Resistance of Stucco-Faced, Gunite-Faced, and

"Knap Concrete-Unit" Walls 15^ Tests of Cement-Water Paints and Other Waterproofings for Unit-Masonry Walls 25^

Properties of a Porous Concrete of Cement and Uniform-Sized Gravel 10<i Experimental Dry-Wall Construction With Fiber Insulating Board 10(4 Physical Properties of Terrazzo Aggregates 15^ Structural and Heat-Transfer Properties of "Multiple Box-Girder Plywood Panels" for Walls, Floors, and Roofs 15^ Relative Slipperiness of Floor and Deck Surfaces 10^ Strength and Resistance to Corrosion of Ties for Cavity Walls 10^ Painting Steel 10^ Measurements of Heat Losses From Slab Floors 15^ Structural Properties of Prefabricated Plywood Lightweight Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by the Douglas Fir Plywood Association 30^ Paint Manual with particular reference to Federal Specifications $L 25 Laboratory Observations of Condensation in Wall Specimens 15^ Building Code Requirements for New Dwelling Construction * Temperature Distribution in a Test Bungalow With Various Heating Devices lOfi Strength of Houses: Application of Engineering Principles to Structural Design $L 50

Paints for Exterior Masonry Walls 15^ Performance of a Coal-Fired Boiler Converted to Oil

_.

15^ Properties of Some Lightweight-Aggregate Concretes With and Without an Air- entraining Admixture 10^

Fire Resistance of Structural Clay Tile Partitions 15^ Temperature in a Test Bungalow With Some Radiant and Jacketed Space Heaters 25^ A Study of a Baseboard Convector Heating System in a Test Bungalow 15i Preparation and Revision of Building Codes 15(4 Fire Resistance of Walls of Lightweight Aggregate Concrete Masonry Units 20^ Stack Venting of Plumbing Fixtures 15^ Wet Venting of Plumbing Fi.xtures 20^

Fire Resistance of Walls of Gravel-Aggregate Concrete Masonry Units

Investigation of Failures of White-Coat Plasters 25(4