DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIRECTOR

BULLETIN 370

THE FIRE-RESISTIVE PROPERTIES OF 

VARIOUS BUILDING MATERIALS

BY

RICHARD L. HUMPHREY

WASHINGTON

GOVERNMENT PRINTING OFFICE

1909

CONTENTS."

Page.

Introduction.............................................................: 7

Scope and character of investigations.................................... 7

Synopsis of tests...................................................... 8

Acknowledgments. .................................................... 12

Source of materials tested.................................................. 12

Apparatus................................................................. 14

Furnace.............................................................. 14

Apparatus for measuring temperatures................................... 15

Preparation of materials tested.....;..............................:......... 16

Method of conducting tests................................................. 17

Fire tests............................................................. 17

Quenching tests....................................................... 17

Strength tests.......................................................... .1.7

Results of tests.............................................. '. ............ 17

Panel 1 (mortar building blocks)....................................... 17

Panel 2 (mortar building blocks)....................................... 19

Panel 3 (mortar building blocks)....................................... 21

Panel 4 (mortar building blocks)....................................... 23

Panel 5 (mortar building blocks)....................................... 25

Panel 6 (mortar building blocks)....................................... 25

Panel 7 (mortar building blocks)....................................... 27

Panel 8 (mortar building blocks)....................................... 28

Panel 9 (mortar building blocks)....................................... 33

Panel 10 (mortar building blocks)...................................... 35

Panel 11 (brick)......................................................... 37

Panel 12 (brick)..............................:........................ 39

Panel 13 (tile)......................................................... 41

Panel 14 (mortar building blocks)...................................... 42

Panel 15 (mortar building blocks)...................................... 44

Panel 16 (mortar building blocks)...................................... 46

Panel 17 (concrete)................................................... 48

Panel 18 (concrete).................................................... 53

Panel 19 (concrete)................................................... 55

Panel 20 (concrete)................................................... 55

Panel 21 (concrete)..................................................... 59

Panel 22 (brick)....................................................... 61

Panel 23 (granite building stone) ........................................ 61

Panel 24 (tile)......................................................... 64

Panel 25 (building stone)............................................... 69

Panel 26 (building stone)............................................... 72

Panel 27 (building stone)............................................... 74

Panel 28 (building stone)............................................... 75

Panel 29 (sand-lime brick)...........'................................... 77

Panel 30 (tile)......................................................... 81

Tables.................................................................... 85

Bibliography. ............................................................ 97

3
TABLES.

Page. 

TABLE 1. Panel 1: Results of compression tests made on fragments of one-piece

double-air-space mortar building blocks after fire test. ........... 85

2. Panel 2: Results of compression tests made on fragments of one-piece

single-air-space mortar building blocks after fire test. ............ ' 86

3. Panel 3: Results of compression tests made on fragments of one-piece

double-air-space mortar building blocks after fire test. ........... 87

4. Panel 4: Results of compression tests made on fragments of one-piece

single-air-space mortar building blocks after fire test. ............ 88

5. Panel5: Results of compression tests made on fragments of one-piece

single-air-space mortar building blocks after fire test. ............ 89

6. Panel 6: Results of compression tests made on fragments of one-piece

single-air-space mortar building blocks after fire test. ............ 90

7. Panel 7: Results of compression tests made on fragments of one-piece

single-air-space mortar building blocks after fire test. ............ 91

8. Panel 8: Results of compression tests made on fragments of one-piece

single-air-space mortar building blocks after fire test. ............ 92

9. Panel 9: Results of compression tests made on fragments of two-piece

mortar building blocks after fire test............................ 93

10. Panel 10: Results of compression tests made on fragments of twopiece mortar building blocks after fire test........................ 94

11. Panel 11: Physical properties of brick before firing.................. 95

12. Panel 12: Physical properties of hydraulic-pressed brick before

firing............'.............................................. 95

13. Pan el 22: Physical properties of common clay brick before firing.... 96

14. Panel 29: Physical properties of sand-lime brick before and after

firing.......................................................... 96

4
ILLUSTRATIONS.

Page.

PLATE I. West and southeast exterior views of furnace..................... 14

II. A, Interior view of furnace; B, View of back of panel............ 16

III. View showing method of quenching a panel after firing.......... 16

IV. Diagram of thermocouples, cold junction bottles, and galvanometer 18

V. Face views of panels 1 and 2 after cooling....................... 18

VI. Face and back views of panel 3 after quenching................. 20

VII. Face and back views of panel 4 after quenching................. 22

VIII. A, Panel 4 during dismantling; B, Face of panels after quenching. 24

IX. Views of panel 5 after quenching and during dismantling........ 24

X. Face and back views of panel 6 after quenching................. 26

XI. A, Panel 6 during dismantling; B, Face of panel 7 after cooling... 28

XII. A, Panel 7 during dismantling; B, Face of panel 8 after cooling... 30

XIII. A, Face of panel 9 after quenching; B, Panel 8 during dismantling;. 32

XIV. Views of panel 9 after quenching and during dismantling........ 32

XV. Face and back views of panel 10 after cooling.................... 34

XVI. A, Panel 10 during dismantling; B, Face of panel 11 after quench! ng. 36

XVII. Face views of panels 12 and 13 after quenching.................. 40

XVIII. Back of panel 13 and face of panel 14 after quenching............ 42

XIX. Views of panel 14 after quenching and during dismantling........ 44

XX. Views of panel 15 after quenching and during dismantling........ 46

XXI. Views of panel 16 after quenching and during dismantling........ 48

XXII. Face and back views of panel 17 after quenching................ 52

XXIII. Face and back views of panel 18 after quenching................ 54

XXIV. Face and back views of panel 19 after quenching................ 56

XXV. Face and back views of panel 20 after quenching................ 58

XXVI. Views of panel 21 before firing and after collapse................ 60

XXVII. Face views of panel 22 before firing and after quenching......... 60

XXVIII. Face views of panel 23 before and after quenching............... 64

XXIX. A, View of stones from panel 23; B, Face of panel 24 after quenching. 66

XXX. A, Back of panel 24 after quenching; B, Face of panel 25 before

firing...................................................... '. 70

XXXI. Face and back views of panel 25 after testing.................... 72

XXXII. Face views of panel 26 before and after firing.................... 74

XXXIII. Face and back views of panel 26 after quenching................ 74

XXXIV. Face and back views of panel 27 after quenching................ 76

XXXV. A, Face of panel 28 after firing and before quenching; B, Stones

from panel 27............................................... 78

XXXVI. A, Face of panel 28 after quenching; B, Stones of panel 28........ 78

XXXVII. Face views of panel 29 before and after quenching............... 80

XXXVIII. Face views of panel 30 before and after quenching............... 82

XXXIX. A, Face of panel 30 after quenching, with all loose pieces removed;

B, Back of panel.30 after quenching...._...................... 82

5
6 ILLUSTRATIONS.

. Page.

FIGURE 1. Diagram showing temperature conditions of panel 1................ 18

2. Diagram showing temperature conditions of panel 2................ 20

3. Diagram showing temperature conditions of panel 3................ 22

4. Diagram showing temperature conditions of panel 4................ 24

5. Diagram showing temperature conditions of panel 5................ 26

6. Diagram showing temperature conditions of panel 6.............'... 28

7. Diagram showing temperature conditions of panel 7................ 30

8. Diagram showing temperature conditions of panel 8................ 32

9. Diagram showing temperature conditions of panel 9................ 34

10. Diagram showing temperature conditions of panel 10............... 36

11. Diagram showing temperature conditions of panel 11............... 38

12. Diagram showing temperature conditions of panel 12............... 40

13. Sketch of glazed building tile used in panel 13.................... 41

14. Diagram showing temperature conditions of panel 13............... 43

15. Diagram showing temperature conditions of panel 14............... 45

16. Diagram showing temperature conditions of panel 15............... 47

17. Diagram showing temperature conditions of panel 16............... 49

18. Diagram showing temperature conditions of panel 17............... 51

19. Diagram showing temperature conditions of panel 18............... 54

20. Diagram showing temperature conditions of panel 19............... 56

21. Diagram showing temperature conditions of panel 20............... 58

22. Diagram showing temperature conditions of panel 21............... .60

23. Diagram showing temperature conditions of panel 22............... 62

24. Diagram showing temperature conditions of panel 23............... 65

25. Sketch of partition tile used in panel 24........................... 66

26. Diagram showing temperature conditions of panel 24............... 68

27. Diagram showing temperature conditions of panel 25............... 71

28. Diagram showing temperature conditions of panel 26............... 73

29. Diagram showing temperature conditions of panel 27............... 76

30. Diagram showing temperature conditions of panel 28............... 78

31. Diagram showing temperature conditions of panel 29............... 80

32. Diagram showing temperature conditions of panel 30............... 84
THE FIRE-RESISTIVE PROPERTIES OF VARIOUS 

BUILDING MATERIALS.

By RICHAED L. HUMPHREY.

INTRODUCTION.

SCOPE AND CHARACTER OF INVESTIGATIONS.

This bulletin contains the results of tests of thirty panels of various building materials, made by the United States Geological Survey

with a furnace in the Underwriters' Laboratories, Chicago, 111., to 

determine the effect of fire and subsequent quenching with water 

on mortar building blocks made of river and slag sands; common, 

hydraulic-pressed, and sand-lime brick; gravel, cinder, limestone, and 

granite concrete; glazed building and partition terra-cotta tile; and 

limestone, sandstone, granite, and marble building stone. The mortar building blocks and the concrete were made in the structuralmaterials testing laboratories; the other materials, except some of 

the common brick, were obtained in the open market at Chicago, 111.

The investigations herein reported are a preliminary part of a 

comprehensive series undertaken with the object of determining the 

fire-resistive properties and rates of heat conductivity of various 

building materials and the comparative efficiency of the various 

methods of fireproofing. These investigations have the further 

object of greatly lessening the liability of loss by fire in government 

buildings and greatly reducing their cost through more efficient 

methods of construction. While the tests are conducted primarily 

for the purpose of obtaining information of essential value to the 

Government it is believed that the results will prove to be of much 

importance to the general public.

The materials were subjected to the direct application of heat for 

two hours and were then, except in five panels, immediately quenched 

with water. Wherever possible, tests were made to determine the 

compressive strength of the materials after this treatment. Temperatures were observed at intervals, and the behavior of the materials during the test and the condition of their surfaces before and 

after the heating and quenching were noted. Photographs of the 

panels were taken to show the effects of the tests.

7
8 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

The tests of the different materials were carried on under as nearly 

identical conditions as possible, but there was some unavoidable 

variation in the conditions. The furnace had never been used for 

such tests, and the operators were inexperienced. The furnace was 

in almost constant use by the Underwriters' Laboratories, and it was 

necessary to arrange the tests so as not to interfere with the regular 

work of those laboratories. It was also necessary to make half the 

tests in winter and the other half in summer, and many of the 

building blocks used in the first tests were subjected to freezing 

weather just prior to testing.

Inasmuch as the tests herein recorded present many features of 

considerable importance, it has been deemed highly desirable to publish a detailed account of them, although the results are preliminary 

and inconclusive, and are presented solely for the purpose of making 

public the information acquired. They should not therefore be used 

as a basis for drawing conclusions, but merely as preliminary data 

regarding the relative fire-resistive qualities of the building materials tested.

SYNOPSIS OF TESTS.

The conditions under which these tests were made were unusually 

severe and none of the material passed perfectly. The temperatures 

used would hardly be reached in an ordinary fire. It was recognized 

from the beginning that these tests would not be comparable with 

those made by other investigators. The relatively few tests that 

have been made of the fire-resistive qualities of building materials 

nearly "all consisted of subjecting floor slabs and columns to the heat 

of a wood fire. There is reason to believe that the tests herein 

described, made in a gas furnace, are more severe than the tests 

made with a wood fire, even though the latter show higher temperatures and last longer. In the gas furnace the flames are forced by a 

blast of air against the panel from the beginning to the end of the 

test; with a wood fire the heat fluctuates and falls decidedly when 

the furnace door is opened and fresh fuel is added.

Much of the damage done to the building materials in this series 

of tests was occasioned by internal stresses, the gas flame heating 

one face of the test pieces much more rapidly than the other face. 

All the materials tested, including the hydraulic-pressed brick, 

cracked more or less. The concrete cracked least, but the tests 

indicate the necessity for using metal reinforcement in concrete walls 

to distribute the effect of the expansion.

The average temperature attained by the faces of the panels 10 

minutes after the gas was lighted was about 324° C. (615.2° F.), 

and nearly half of the panels had been subjected to freezing weather 

just prior to the tests. The average temperature of the face of one 

panel of building blocks rose from 0° to 450° C. (32° to 842° F.) in
SYNOPSIS OF TESTS. 9

the first 10 minutes of firing, while that of another panel of the same 

material ranged from 22° to 600° C. (71.6° to 1,112° F.) during the 

same interval.

Although the results obtained from these tests will not be critically analyzed in this bulletin, a few of the more important features 

will be pointed out.

A fact brought out most clearly by these tests is the low heattransmission rate of Portland cement mortars and concretes. This 

is one of the desirable qualities in materials intended for fireproofing 

purposes. For marking the cement blocks linen tags were fastened 

by wire nails to the interior walls at the time of molding. Most of 

these tags remained in place during the test, and when the walls 

were dismantled the tags in every case were found entirely undamaged.

A study of the curves at the bottom of the diagrams (figs. 1-12, 

14-24, 26-32) will show the comparatively slight increase ( in the 

temperatures of the backs of the blocks during the test. The rise 

in temperature of the backs of the building blocks made of riversand mortar varied from 25° to 40° C. (77° to 104° F.), while the rise 

in the average temperatures of the faces of the cement blocks ranged 

from 650° to 900° C. (1,202° to 1,652° F.). The backs of the mortalblocks, made of slag sand, showed a rise of temperature of only 10° C. 

(30 ° F.), while the faces were heated up to 800 ° C. (1,472 ° F.). The 

low rate of heat conductivity of the mortar blocks is shown by the 

slowness with which the temperature of the backs of the panels increased in comparison with that of the faces.

An average of all the tests shows that about 90 per cent of the 

maximum temperatures attained by the faces of the panels were 

reached in one hour, while in the case of the mortar blocks the increase in temperature of the backs of the panels in one hour was only 

about 20 per cent of the total increase in the two hours. Of the solid 

concrete panels the cinder concrete showed the smallest increase in 

the temperatures of the backs of the walls, and the granite concrete 

the largest. The total increase in the temperatures of the mortar 

panels was about the same as the total increase in the temperatures 

of the backs of the concrete, but the increase in one hour was somewhat greater in the case of concrete.

The damage done to the faces of the mortar and concrete panels 

would probably be caused at a temperature about half that of the 

maximum temperatures reached, owing to the water of crystallization being driven from the mortar. This thin layer of dehydrated 

mortar may have formed a protective coating and prevented deep 

dehydration.

The backs ol the brick panels also showed a small increase in temperature, but the natural building stones and the tiles proved poorer
10 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

nonconductors of heat. The temperature of the back of a panel 

composed of plastered tiles increased to 128 ° C. (262.4° F.).

It is apparent that the strength of the webs of ordinary hollow 

blocks is insufficient to resist the stresses set up in these tests, as in 

many tests the rapid rise in temperature and the subsequent quenching of one of the faces of the blocks caused the webs to split. It was 

noticeable that the richer the mortars used in these blocks the better 

they withstood the tests. The amount of water used in mixing the 

mortars had a similar effect on the fire-resistive qualities; the mortars 

mixed with the greatest percentage of water gave the best results. 

This may be clearly seen in the photographs of the mortar blocks 

after the water treatment, where the wetter, richer mixtures often 

stand out apparently undamaged, in contrast with the spalled, 

damaged faces of the leaner, drier blocks.

When blocks were cracked or spalled before the application of 

the water the damage appeared to be greater in the dry mixtures 

containing the greatest percentage of sand, and it was further observed during the fire test that the richer mixtures warmed up more' 

slowly than the others. It is apparent that one of the causes of 

weakness in the hollow cement building blocks under these fire tests 

was the weakness of the concrete, a too dry and lean mixture, which, 

coupled with the thinness of the webs, provided insufficient strength 

to resist the stress due to the rapid expansion of the face. It is quite 

possible, as was shown in some of the block tests, to make blocks 

which will pass the conditions perfectly; the web must be thick 

enough to give the necessary strength.

A close examination of the blocks that had not been quenched 

showed that the 1:2 blocks were seldom affected by heat to a greater 

depth than f inch, while the 1:8 blocks frequently showed the effect 

of the fire to a depth of 2 inches. The blocks made of slag sand 

resisted the test better than those made of river sand. Before the 

water was applied to the slag-sand blocks no damage was apparent, 

although it must be remembered that close examination of the panels 

between the fire and water treatments could not be made on account 

of the heat. After the quenching the faces of the 1:1$ slag-sand 

blocks were found to be washed away to a depth of \ to f inch; 

and those of the 1:2} to a depth of $ to f inch; while the I mixtures 

were damaged only to a depth of ^ to f inch. The surfaces were rough 

and pitted, but hard. In only one block was the web cracked through.

There was great difficulty in getting accurate results from strength 

tests of irregularly shaped fragments from the backs and fronts of 

blocks after the fire and quenching tests, and the results are too inconsistent to be conclusive. The average compressive strength of the 

faces of blocks was about two-thirds to three-fourths of that of their 

backs, varying with the proportions and consistencies.
SYNOPSIS OF TESTS. 11

The brick panels probably withstood the tests better than the 

other materials. The common brick tested comprised unused new 

Chicago brick, and used St. Louis brick. Fifty per cent of the new 

bricks were split, while 60 to 70 per cent of the old bricks were not 

damaged. Lime knots seemed to be responsible for most of the 

damage to the new bricks, as they were found at the bottom of nearly 

all the cracks. The bricks at the back of the panels were entirely 

unaffected. While the strength tests are not conclusive,' there is 

apparently little difference in the strength of these bricks before and 

after firing:

The hydraulic-pressed brick withstood the test very well. Np 

damage was apparent after the firing and before the water was 

applied, and although a number of the bricks cracked, 70 per cent of 

them were found to be sound after quenching.

The sand-lime brick did not withstand the test as well as expected, 

but the sample tested, which was purchased at random, appeared to 

be somewhat below average quality.

It was difficult to determine whether the limestone, granite, gravel, 

or cinder concrete sustained the least damage. The faces of all the 

panels were more or less pitted by the fire and washed away by the 

stream of water. The test was unfair to the cinder concrete, as the 

cinder was very poor, containing a large percentage of unburned 

coal; however, the sample selected was the best of six or eight investigated in St. Louis. During- the fire test the coal ignited and left 

the surface of the concrete very rough and badly pitted. The limestone aggregate in the face calcined, and the granite aggregate split 

and broke away from the surface mortar. The granite concrete 

probably behaved the best. The damage in no case extended 

deeply, probably not more than 1$ inches. The evidence shows 

that even at this depth the temperature was comparatively low. 

The high stresses produced in the panels by the rapid rise of temperature of the faces while the backs remained cool caused cracks. 

On taking down the panels the blocks of concrete were found to be 

cracked vertically for some distance back from the face.

The serious damage to the various natural building stones precludes any comparison among them.

The tile tested was bought in the open market, and in one panel 

was taken from a lot of material about to be erected in a building. 

Large percentages of the faces of the tiles were washed away by the 

water, and the material composing the faces became soft and could 

be easily crumbled in the fingers. There was a comparatively rapid 

rise in the temperature of the back of the panels. The plaster on the 

panel of partition tile fell off a few minutes after the test was started.

Heretofore fire tests of building material have been made at random and scarcely any two tests are comparable one with the other;
12 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

it is therefore hoped that the next series of tests made in this type of 

furnace, where with the experience gained the conditions can be 

more closely controlled, will lead to much more valuable results.

ACKNOWLEDGMENTS.

These investigations were made possible through the hearty cooperation and proffer of facilities by the Underwriters' Laboratories, Inc., 

located at 382 Ohio street, Chicago, 111. The courtesies and cooperation of Prof. R. Burnham, of the Armour Institute, in whose laboratories the compression tests on the treated test pieces were made, 

are hereby acknowledged.

The building-block machines used in making the mortar blocks 

were selected by a special committee of the United Concrete Block 

Machinery Manufacturers' Association; the machines represented 

different types and were loaned through the courtesy and cooperation of the following companies:

American Hydraulic Stone Company, Denver, Colo. 

Cement Machinery Company, Jackson, Mich. 

Dykema Company, Grand Rapids, Mich. 

Miracle Pressed Stone Company, Minneapolis, Minn. 

P. B. Miles Manufacturing Company, Jackson, Mich.

The cement used in the building blocks and the concrete \vas a 

mixture of a number of brands of cement which were donated by the 

following companies:

Atlas Portland Cement Company, Hannibal, Mo. 

Edison Portland Cement Company, New Village, N. J. 

lola Portland Cement Company, lola, Kans. 

Lehigh Portland Cement Company, Mitchell, Ind. 

Omega Portland Cement Company, Jonesville, Mich. 

St. Louis Portland Cement Company, St. Louis, Mo. 

Virginia Portland Cement Company, Fordwick, Va.

The sand referred to as "Meramec River sand," used in the building 

blocks and concrete, was contributed by the Union Sand and Material 

Company, of St. Louis, Mo. The slag sand used in a few of the blocks 

was contributed by the Carnegie Steel Company of Pittsburg, Pa.

SOURCE OF MATERIALS TESTED.

Common brick. Two samples of common brick were tested, one a 

Chicago "brick selected in the yard of the makers, and the other a 

St. Louis brick taken from the foundation of a dismantled briquetting 

machine of the Government's fuel-testing plant, Forest Park, St. 

Louis, Mo.

Hydraulic-pressed brick. The hydraulic-pressed brick was manufactured in Indiana and taken from a pile being used in the construction of a building in Chicago.
SOURCE OF MATERIALS TESTED. 13

Sand-lime brick. The sand-lime brick was manufactured in Indiana and taken from a stock pile in Chicago.

Mortar building blocks. The building blocks were molded at the 

Government's structural-materials testing laboratories, St. Louis, 

Mo., on five different designs of machines representing distinct types.

The blocks in tests 1 to 10, inclusive, were made of sand dredged 

from Meramec River at Drake, Mo., and "typical Portland" cement. 

They were made in three different consistencies, damp, medium, and 

wet; and in three proportions, 1:2, 1:4, and 1: 8. An equal number 

of each consistency made in the three proportions were tested in the 

same panel.

The Meramec River sand was of average quality and free from 

silt, its grading being quite uniform. The results of a large number 

of tests with this sand and a description of the "typical Portland" 

cement, which is a thorough mixture of a number of brands, are given

in Bulletin 331.°

The blocks in panel 14 were of "typical Portland" cement and 

slag sand, made of medium consistency and in the proportions of 

1:1$, 1:2$, and 1:4.

In panels 15 and 16 were tested two parallel series of Meramec 

sand blocks of medium consistency, mixed in proportions of 1:2,1:4, 

and 1:8; those in panel 15 were cured in the moist room, while those 

in panel 16 were cured in dry air. These last two sets of blocks and 

the slag-sand blocks were made on the single-air-space type of 

machine only.

Terra-cotta tile. Two kinds of terra-cotta tile were tested, one a 

hollow glazed building tile, 8 by 8 by 16 inches, having a £-inch web, 

with four core holes running throughout its length, and the other a 

partition tile, 5 by 12 by 12 inches, having a f-inch web and three 

core holes. The former tiles were taken from a stock pile in Chicago; the latter were obtained by purchase from a lot of material that 

had been delivered by the manufacturers at the site of a building in 

course of construction in which they were being used for fireproofing.

Concrete. The concretes tested were pieces of broken beams that 

had been tested in the Government's structural-materials testing 

laboratories at St. Louis, Mo. The pieces were 8 by 11 inches in 

cross section and of various lengths. They were fired with the 

11-inch face exposed. In making the concretes four distinct types 

of aggregate had been used limestone, granite, gravel, and cinder. 

The aggregate was sized to pass a 1-inch screen and be retained on a 

£-inch screen. The concretes had been mixed in proportions of 1 of 

cement, 2 of Meramec River sand, and 4 of aggregate, and were of 

medium consistency.

a Humphrey, Richard L., and Jordan, William, jr., Portland cement mortars and their constituent 

materials: Bull. U.S. Geol. Survey No.331,1908.
14 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

The limestone was obtained in St. Louis, Mo. The gravel was 

dredged from Meramec River at Drake, Mo.; it was clean, hard, and 

flinty. The granite was the red granite from Graniteville, Mo. 

The cinder, obtained from a large power house in St. Louis, was 

poor, containing 24.5 per cent of combustible material.

Building stone. The four kinds of building stone tested sandstone, limestone, marble, and granite were obtained by purchase 

in the open market in Chicago, 111. There were two kinds of limestone, one the Bedford limestone (Carboniferous) from Bedford. 

Incl., and the other a Niagaran magnesian limestone from Joliet, 111, 

The sandstone was from the Carboniferous at Cleveland, Ohio. The 

marble was-from Georgia, and the granite from Thousand Islands, 

Canada, except one sample of a granite from Maine, which was 

reported to be such as was used in the construction of the post-office 

building in Chicago, 111.

APPARATUS.

Furnace. The apparatus in which these tests were made is similar 

to that generally used in determining the fire-resistive qualities of 

fire doors and windows. It comprises a gas furnace with a movable 

steel-frame fire-brick wall or door 14 inches thick (A, PL I, A) that 

shuts off the furnace from a radiation chamber. The distance 

between the permanent back wall of the furnace and the movable 

wall is 13£ inches. The movable wall is hung from the lower flange 

of an I beam by rollers and is easily moved out of position by a weight 

(B; PI. I, A) attached to a wire cable. The wall has an arched 

opening 6 feet wide and 9 feet high. The material to be tested is 

built up in this opening as a panel (PL I, B].

The stationary back wall of the furnace contains holes through 

which air is admitted to control the temperature. Back of this wall

are piping and valves for the control of the air and gas supply (PL I, 

A). The air pressure for the flame is maintained by a motor-driven 

fan (D, PL I, A). Gas enters the fire chamber at the bottom through 

burners which are below the level of the floor and do not show in the 

accompanying view of the interior of the furnace (PL II, A)'. The 

piping against the face of the wall in this view is a water pyrometer.

When a panel is ready for testing it is drawn into position in front 

of the main wall by a hand winch (C, PL I, A) and held there by a 

latch. The opening around the edges is sealed by fire clay. Then 

the gas is turned on and lighted by a torch inserted through a small 

door (E, PL I, A). The observer can watch the behavior of the 

furnace and the materials under test through three small mica peep 

holes in the sides of the furnace (F, PL I, A}.

At the end of the heat treatment the latch is released and the 

weight at once draws the wall from the furnace. In a regular test the 

material in the panel is immediately quenched with water from a nozzle.
U. S. GEOLOGICAL SURVEY

A. WEST VIEW OF FURNACE, SHOWING RADIATION CHAMBER AND PANEL (A) IN POSITION

FOR QUENCHING.

1',. SOUTHEAST VIEW OF FURNACE, SHOWING FIRE CHAMBER AND PANEL BUILT UP IN

MOVABLE WALL.
APPARATUS. 15

Throughout this bulletin the side of the panel subjected to the 

heat of the furnace is referred to as the face of the panel; the opposite 

side, which is exposed to the air, is referred to as £he back of the 

panel.

Apparatus for measuring temperature. The temperatures of the 

furnace and of the face of the panel during the tests herein described 

were determined by means of platinum and iridium thermocouples; 

the temperatures of the back of the panel were measured by means 

of mercury thermometers. In addition, the average temperature of 

the interior of the furnace was found by the water pyrometer.

Four thermocouples were inserted through the back wall into the 

furnace chamber, each extending through a steel tube 3^ inches 

long and f inch in diameter. Smaller clay tubing surrounded the 

couples and protected them from the steel tubing. The couples 

projected into the fire chamber about 4J inches, but only the point

of each couple, about f inch, was exposed, the rest of the 4| inches 

being protected from the fire by a cone of fire clay.

The temperatures of the face of the panel were measured by six 

thermocouples incased in clay tubing that passed through f-inch 

steel tubing laid in the mortar joints. The ends of the tubes extended 

within \ inch of the face of the panel, and the points of the couples 

were placed about iV incn back from the face and surrounded with 

a thin coating of fire clay. To the free ends of the couples were 

soldered pieces of copper wire about 3 feet long; cold junction bottles 

were used to keep the soldered junctions of the ends of the couples 

and the copper wire at a constant temperature. These bottles had 

large mouths closed by corks and were filled with water and surrounded with magnesia pipe covering. Through each cork were 

inserted two test tubes, about 6 inches long, and a thermometer. 

Each test tube held a junction. From the bottles the copper wires 

led through a switch to an Englehardt galvanometer. Prior to the 

tests the thermocouples were calibrated against this instrument.

The general arrangement of the thermocouples, cold junction 

bottles, switch, and galvanometer is shown in Plate IV. Plate II, B, 

shows the thermometers and cold junction bottles in position at the 

back of a panel.

The temperatures of the back of each panel, taken to determine 

the rate of heat transmission, were measured by thermometers held 

in contact with the surface of the panel by small lumps of fire clay.

The temperatures recorded by each couple, the water pyrometer, 

the thermometers against the back of the panels, and the thermometers in the junction bottles were platted after each test (figs, loto 12,. 

14 to 24, 26 to 32). The curve drawn through the platted points 

represents the average in each test.
16 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

The Weather Bureau records of the minimum and maximum air 

temperatures, the humidity, and the wind direction for the particular 

day of each test are given below the diagrams showing the above 

curves.

PREPARATION OF MATERIALS TESTED.

Preparation of building blocks. The methods used in molding 

and curing the concrete building blocks at the Government's structural-materials testing laboratories are described in Bulletin 329 . a 

The proportions, while stated in parts by volume, were actually by 

weight, allowance being made for the percentage of moisture in the 

sand, which was determined as used. The mixing was done in a | 

cubic yard Chicago cubical concrete mixer, the sand and cement being 

thoroughly mixed before the water was added. The three consistencies, indicated by the terms "damp," "medium," and "wet," are 

defined as follows: (1) In damp consistency the per cent of water 

used gives the driest mixture which can be handled in all five types 

of block machines; (2) medium consistency is halfway between 

damp and wet consistencies; (3) in wet consistency the percentage 

of water used gives the wettest mixture which can be handled.

All the blocks, with the exception of those made on an American 

Hydraulic Stone Company machine, a pressure machine, were hand 

tamped, and great care was taken to tamp them all in the same manner and for the same length of time. The blocks in any one batch 

were not permitted to vary more than 1 per cent in weight. They 

remained on the pallets 60 hours, and then, with the exception of a 

set left in the air of the laboratory, were placed in a moist room, 

where they were sprinkled at 8-hour intervals.

For transportation to Chicago the blocks were packed in straw in 

a refrigerator car, and the car was filled with live steam and. sealed. 

On reaching the Underwriters' Laboratories they were piled in a 

warm, dry room until tested. The length of time that each set of 

blocks remained in the moist room, in the car, and at the Underwriters' Laboratories is noted in the description of each test.

The blocks were built up in the panel without breaking the joints, 

in order to obviate the necessity of cutting any of the blocks.

Preparation of concrete. The concrete, consisting of portions of 

unreinforced beams which had been tested, was stored in a moist 

room and sprinkled at 8-hour intervals, both before and after it was^ 

tested. For a description of the method of mixing and molding the 

concrete, see Bulletin 329.

Preparation of building stone, brick, and tile. These building 

materials were placed in the panel, as nearly as space would allow, in 

exactly the same way that they would be laid in the wall of a building.

o Humphrey, Richard L., Organization, equipment, and operation of the structural-materials testing 

laboratories at St. Louis, Mo.: Bull. U.'S. Geol. Survey No. 329, 1908.
U. S. GEOLOGICAL SURVEY BULLETIN 370 PLATE I

A. VIEW OF FURNACE WITH PANEL REMOVED, SHOWING SECONDARY 

AIR INLETS AND WATER PYROMETER.

li. VIEW OF BACK OF PANEL, SHOWING THE COLD JUNCTION BOTTLES AND THERMOMETERS

IN PLACE.
U. S. GEOLOGICAL SURVEY 

VIEW SHOWING THE METHOD OF QUENCHING A PANEL AFTER BEIN
U. S. GEOLOGICAL SURVEY BULLETIN 370 PLATE IV

DIAGRAM SHOWING THE ARRANGEMENT OF

THE THERMO-COUPLES IN THE TEST PANEL

AND OF THE COLD JUNCTION BOTTLES

DIAGRAM SHOWING THE 

ARRANGEMENT OF THE THERMO-COUPLES

IN THE FURNACE AND 

OF THE COLD JUNCTION BOTTLES

DIAGRAM SHOWING THE ARRANGEMENT OF THERMOCOUPLES. COLD JUNCTION BOTTLES, AND GALVANOMETER.
FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS. 17 

METHOD OF CONDUCTING TESTS.

Fire tests. The test wall with the panel filled with the material to 

be tested was allowed to dry out for several hours, and was then 

drawn into position by means of the winch, and latched. The openings around this wall and the furnace were sealed up with fire clay. 

The pyrometers were then placed in position in the joints and the 

thermometers were attached to the back of the panel, as shown in 

Plate II, B. The wires from each thermocouple (PI. IV) led to a 

10-point switch, connected with the galvanometer, placed on a table 

a short distance back of the panel. One of the operators, seated at 

this table, recorded the readings of the galvanometer on each of the 

ten couples at 10-minute intervals; the other operator regulated the 

supply of gas and air, read the thermometers, and noted the behavior of the furnace and of the panel under test.

An effort was made to obtain the maximum temperature (1,700° F.) 

within one-half hour after starting the test, and to maintain this 

temperature as nearly constant as possible throughout the succeeding time. At the end of 2 hours the thermometers, thermo-couples, 

and cold junction bottles were quickly removed, the gas turned off, 

and the latch raised, allowing the wall to be pulled out by means of 

the counter weight.

Quenching tests. As soon as the wall was free from the furnace the 

face of the panel which had been exposed to the heat was quenched by 

a stream of water. The water was applied for 5 minutes at a pressure 

of 50 pounds to the square inch through a $~inch nozzle held 20 feet 

from the face of the panel (PI. III). The average interval between 

shutting off the gas and' applying the water was 1 minute. Photographs were taken of the face and back of the panel both before and 

after the test.

Strength tests. As soon as the panel had become cool enough to 

permit handling the test pieces, it was dismantled and such test 

pieces as could be obtained were hauled to the Armour Institute, 

Chicago, where they were tested for compressive strength by a 

200,000-pound Olsen testing machine. The results of the strength 

tests are given in Tables 1 to 10, inclusive.

RESULTS OF TESTS.

PANEL 1 (Mortar Building Blocks).

Material. Panel 1 was composed of 27 "typical Portland" cement 

and Meramec River sand one-piece double-air-space blocks, laid up in 

fire clay without breaking joints. There were three blocks each, of 

1:2, 1:4, and 1:8 mixtures, damp, medium, and wet. The blocks had 

been stored in a moist room and sprinkled twice daily at the St. Louis 

laboratories 52 days, packed in straw in a refrigerator car which was 

73087 Bull. 370 09 2
18 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

US f\

z

6__e\

, 4

FACE OF

3.4

600

' a

FURNACE

\r WATER PYROMETER

BACK OF PANEL

r/ME /

FIGURE 1. Diagram showing temperature conditions in the furnace and on the back of panel 1. Temperature: Maximum, 34°; minimum, 28°; mean, 31°. Relative humidity: 7 a. m., 95; 7 p. m., SC. Direction of prevailing wind, east.
U. S. GEOLO&eAL SURVEY 

A. FACE OF PANEL 1, CEMENT MORTAR BUILDING BLOCKS, AFTER

COOLING IN AIR.

B. FACE O
KESULTS OF TESTS. 19

en route to Chicago 3 days, stored in a warm room in the Underwriters' 

Laboratories 8 days, and were finally tested at the age of 63 days. The 

panel was laid up in freezing weather.

Test. Firing started at 2:10 p. m. January 17, 1907, and continued for 2 hours 3£ minutes. The panel was cooled in air after the 

test without the application of water.

In 38 minutes steam appeared through the joints at the top of 

the panel. At the expiration of 55 minutes the blocks began to 

sweat, particularly those of 1:2 and 1:4 proportions. The top of the 

panel was warmer than the middle and the lower portions, especially 

the 1:8 blocks. The back of the 1:8 blocks felt warmer than the backs 

of those of the richer mixtures.

The variations of temperature of the furnace, determined by the 

water pyrometer and the thermocouples, of the temperature of the 

face and back of the panel, and of the cold junction bottles are shown 

in figure 1.

Results. Plate V, A, shows the face of the panel after cooling. 

Vertical cracks along the webs, clearly shown in the plate, developed 

in each row of blocks. There were no signs of spalling. The surface of 

the 1:8 blocks could be rubbed away easily with the finger, that of 

the 1:2 blocks with difficulty. The faces of the 1:2 blocks were discolored by the heat to a depth of $ to f inch, that of the 1:4 to a 

depth of about £ to 1 inch, and that of the 1:8 to a depth of about 1 £ 

to 2 inches. The damp, medium, and wet consistency blocks showed 

no difference in appearance. The back of the panel showed no apparent change.

On dismantling the panel it was found that every block had 

cracked across the web and split out at the face, leaving the inner web 

intact. All consistencies and proportions failed in about the same 

manner.

The results of the compression tests on the fragments of blocks 

after the fire tests are given in Table 1.

PANEL 2 (Mortar Building Blocks).

Material. Panel 2, one-piece single-air-space blocks, was made 

up the same as panel 1, but had been in the St. Louis laboratories one 

day less and in Chicago one day more.

Test. Firing started at 3.11 p. m. January 18, 1907, and continued for 2 hours 1 minute. The panel was cooled in. air without 

application of water.

In 30 or 40 minutes after starting steam began to come through 

the mortar joints. At 60 minutes the back of the wall began to 

sweat and to get warm to the hand, getting warmer faster at the top
20 FIRE RESISTANCE OP VARIOUS BUILDING MATERIALS.

FIGUBE 2. Diagram showing temperature conditions in the furnace and on the back of panel 2. Temperature: Maximum,37°; minimum,34°;mean,36°. Kelativehumidity: 7 a.m., 91; 7p.m.,94. Direction of prevailing wind, southeast.
U. S. GEOLOGICAL Simv 

~

'ju'

Lf,-f

yl. FACE OF PANEL 3, CEMENT MORTAR BUILDING BLO'.Ao, AFTER I IRING 

AND QUENCHING.

11. BACK OF PA
RESULTS OF TESTS. 21

than at the bottom. The 1:2 blocks warmed more slowly than those 

of leaner proportions.

Curves showing the variations of the temperature are given in 

figure 2.

Results. When removed from the furnace no cracks were visible, 

but while cooling small hair cracks developed all over the blocks! 

On the 1:2 blocks, especially the wet mixtures, these cracks were 

very fine, but on the 1:4 and 1:8 blocks they were coarser and. more 

extensive. The surfaces appeared smooth, but could be easily 

scratched. Plate V, B, shows the face of the panel after cooling in 

air. The hair cracks are too small to be visible in the photographs. 

On taking the panel down all the blocks were found to have cracked 

across the web nearest the fired side. To remove the detached fired 

face without cracking it vertically was difficult.

Table 2 gives 'the results of the strength tests on fragments of the 

fired blocks, one column giving the strength of the face of the block 

exposed to the fire and another the strength of the back of the blocks. 

The table shows conclusively the loss in strength of the fired face.

PANEL 3 (Mortar Building Blocks).

Material. Panel 3 consisted of one-piece double-air-space blocks 

exactly like those in panel 1, except that they had been made four 

days later and therefore were four days less time in St. Louis, and 

the same length of time longer in Chicago. The panel was laid up in 

the afternoon of January 19, 1907, during a rain storm. The temperature on January 20 was below freezing all day:

Test. Firing started at 3 p. m. January 21, and continued for 2 

hours. Water at a temperature of 36° F. was applied to the panel 

for 5 minutes, but not until 19 minutes after the gas was turned off, 

as the door stuck in the furnace.

From 3 to 5 minutes after starting the test considerable snapping 

was audible, but no cracks became visible. In 10 minutes a 1:8 dry 

block opposite an air jet spalled at one corner, and 5 minutes later 

the spalling continued across the block and the lower edge became 

loose. At 20 minutes another 1:8 dry block spalled along the lower 

edge and the right-hand side. This spalling extended up 3 to 4 inches, 

though it did riot penetrate more than | to £ inch. At 70 minutes 

the blocks began to sweat and steam came from the joints.

Curves shoAving the variations of the temperature throughout the 

test are given in figure 3.

Results. Vertical cracks on each side of the center webs showed 

plainly before the application of the water. Plate VI, A, shows the 

face and Plate VI, B, the back of the panel after quenching. These 

views show clearly how different blocks met the tests, the richer wet
22 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

/OOO 

300 

800 

700 

600 

SOO 

400 

300 

200 

JOO. 

0

3

FACE OF PANEL

700 

600 

SDO 

400 

300 

EOO 

/00 

0

900 

SOO 

700 

600 

SOO 

400

300

200

/00

0

JO

20

/O

0

-/O

FIGUEE 3. Diagram showing temperature conditions in the furnace and on the bade of panel 3. Temperature: Maximum, 27°; minimum, 4°; mean, 10°. Relative humidity: 7 a.m.,SO; 7 p. m.,83. Direction of prevailing wind, southeast.

FURNACE

\

WATER PYROMETER

BACK OF PANEL
U. s. GEOLOGICAL SURVEY

A FACE OF PANEL 4, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING 

AND QUENCHING.

B, BACK OF PA
EESULTS OF TESTS. 23

blocks withstanding it much better than the lean damp blocks. A 

peculiarity of the behavior of this type of block during the test may 

be seen in Plate VI, B. The end webs split away from and parallel 

to the face of the blocks, but the middle web remained intact and 

the face split away from it at each side, leaving from 1 to 4 inches 

of the face in place.

Table 3 gives the compressive strength of the fragments.

PANEL 4 (Mortar Building Blocks).

Material. Panel 4 was made of one-piece single-air-space blocks 

exactly like those in panel 2, except that they were made and tested 

5 days later, and therefore remained in St. Louis 5 days less time and 

in Chicago 5 days longer.

Test. Firing started at 2.36 p. m. January 23, 1907, and continued

for 2 hours and 1 minute. Water at a temperature of 36° F. was

applied for 5 minutes and 20 seconds, beginning within 1 minute 

after the gas was turned off.

In 20 minutes a block on the left-hand side, third row from the bottom, opposite an air jet, bulged out at the center about \ inch and 

cracked horizontally at about the center. At 26 minutes a block on 

the right-hand side in the sixth row bulged and cracked vertically. 

At 32 minutes the block on the left-hand side in the third row 

bulged still more, and 2 minutes later the face fell off. At 37 minutes the center block in the third row opposite an air jet bulged 

about \ inch. At 80 minutes the blocks began to sweat and steam 

came through the joints.

' The curves showing the variations of the temperature throughout 

the test are given in figure 4.

. Results. Plate VII shows the face and back after firing and 

quenching. Plate VIII, A, shows the condition of the blocks during 

dismantling. When the panel was withdrawn from the fire the surfaces of the blocks were smooth except where the blocks had spalled. 

No cracks were visible. During the application of the water all the 

blocks spalled, but, as may be seen from the plates, this spalling was 

most severe on the lean damp blocks. The fourth and seventh rows 

from the bottom in Plate VII, A, are 1:2 blocks; the rows next 

beneath are 1:8 blocks. The difference in the damp, medium, and wet 

consistency blocks in the two rows is perceptible. The 1:8 and 1:4 

proportions were badly spalled and washed away.

On dismantling the panel all the blocks were found to be split

across the webs. These cracks were along the fired face except in

 two or three cases, where the webs split away from both the face and

the back. A piece of wood left in the interior of one of the blocks,

was slightly scorched, but not at all charred.

The strengths of the fragments are given in Table 4.
24 FIRE .RESISTANCE OF VARIOUS BUILDING MATERIALS.

FIGURE 4. Diagram showing temperature conditions in the furnace and on the back of panel 4. Temperature: Maximum, 22°; minimum, 6°; mean, 14°. Relative humidity: 7 a.m.,83; 7p.m.,85. Direction of prevailing wind, northwest.
U. S. GEOLOGICAL SURVEY

A. PANEL 4, CEMENT MORTAR BUILDING BLOCKS, DURING DISMANTLING. B. FACE OF 
U. 8. GEOLOGICAL SURVEY

. 1. BACK OF PANEL 5, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING 

AND QUENCHING. />. PANEL 5, C
KESULTS OF TESTS. 25 

PANEL 5 (Mortar Building Blocks).

Materials. Panel 5 consists of one-piece single-air-space blocks 

made in the same way and of the same proportions and consistencies 

as those previously tested. They were stored in a moist room at 

St. Louis 45 days and at Chicago 16 days, and were tested at the age 

of 64 days. The panel was laid up in freezing weather and was frozen 

when the test began.

Test. Fire started 10.14 a. m. January 25, 1907, and continued 

for 2 hours and 5 minutes, after which the panel was quenched with 

water at a temperature of 36° F., applied for 5 minutes. The fire 

worked badly, the panel at the top not heating up as well as desired. 

There was considerable snapping and cracking at the start, which 

stopped as soon as the panel became well heated.

In 25 minutes a block on the right-hand side, third row, spalled 

slightly at the center and showed some horizontal cracks. During 

the remainder of the test the panel showed no change.

Curves showing the variations of the temperature throughout the 

test are given in figure 5.

Results. As the top of the furnace did not heat up properly, the 

blocks in the upper part of the panel were not affected as much as 

those in the lower and middle portions. Plate VIII, B, shows the 

face of the panel after the test, Plate IX, A, the back of the panel 

after the test, and Plate IX, B, the panel during dismantling. The 

surfaces of the blocks were badly pitted, but no cracks appeared 

except in the 1:8 damp blocks. The 1:4 blocks spalled. badly; the 

1: 2 blocks slightly. The difference in the behavior of the rich wet 

blocks and the lean damp blocks can clearly be seen in Plate VIII, B.

On dismantling the panel the blocks were found to be all cracked 

along the webs, so that the faces could be removed without disturbing 

the backs. It was also found that the faces of the blocks were 

cracked vertically, though the cracks did not show badly; yet few 

of the faces could be removed in one piece. Most of the webs 

cracked close to the fired face, but in a few the crack developed near 

the back of the block and the fired face remained attached to the web.

The strength tests of the fragments of these blocks are given in 

Table 5.

PANEL 6 (Mortar Building Blocks).

Material. Panel 6 consisted of one-piece single-air-space blocks, 

made in the same way and of the same proportions and consistencies 

as those previously tested. They were stored in a moist room in St. 

Louis 41 days and in Chicago 20 days and were tested at the age of 

64 days.
FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

T/ME /# M//WTES

FIGURE 5. Diagram showing temperature conditions in the furnace and on the back of panel 5. Temperature: Maximum, 24°; minimum, 1°; mean, 12°. Relative humidity: 7 a. on., 82; 7p.m., 62. Direction 

of prevailing wind, northwest.
U. S. GEOLOGICAL SURVEY

A. BACK OF PANEL 6, CEMENT MORTAR BUILDING BLOCKS, AFTER 

FIRING AND QUENCHING.

B. FACE OF PANEL 6, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING 

AND QUENCHING.
RESULTS OP TESTS. 27

Test. Firing started at 12.35 p. m. January 29, 1907, and continued for.2 hours and 1 minute. 'The panel was then quenched with 

water at a temperature of 36° F. for 5 minutes. The fire gave a 

uniform temperature from tlje start.

In 10 minutes the right-hand and left-hand blocks in the third 

row spalled off around the inner edges. At 30 minutes the left-hand 

block in the sixth row spalled around the bottom edge to a depth of 

about 1 inch. The spalling extended upward over the block to a 

height of about 3 or 4 inches, and the material became loose and fell 

off. The center blocks in the top row spalled similarly, but less 

severely. At 60 minutes steam began to appear through the mortar 

joints.

Curves showing the variations of the temperature throughout the 

test are given in figure 6.

Results. Plate X, £, shows the face of the panel and Plate X, A, 

the back of the panel after the test, and Plate XI, A, the panel during 

removal. Before quenching the faces of the blocks seemed little 

affected, but after the application of the water the surfaces appeared 

badly spalled and washed away. The photograph (PL X, B] shows 

that, as in previous tests, the lean damp blocks were the most severely 

affected, but the 1:8 wet and the 1:8 medium suffered little less than 

the 1:8 damp. The 1:2 blocks showed no signs .of surface cracks, 

but were almost as badly washed away as the 1:4 blocks. The 1:2 

wet blocks were affected considerably less than the 1:2 medium and 

1:2 damp blocks. The 1: 4 medium, wet, and damp blocks seemed 

affected about equally. Only two of the blocks could be taken from 

the wall intact. These were a 1: 4 wet and a 1: 4 damp in the center 

row. All the others were cracked across the end webs, and in most 

cases the faces of the blocks split vertically along the inner web. In 

a few cases the end webs cracked near the back face, but in all cases 

the center web remained attached to the back face. This web in 

many cases was attached to a small piece of the front face, the front 

face having cracked away from it on either side.

The strength tests on these blocks are given in Table 6.

PANEL 7 (Mortar Building Blocks).

Material. Panel 7 was made of one-piece single-air-space blocks, 

similar to those in panel 6. They were stored in the moist room in 

St. Louis 37 days and in Chicago 23 days, and were tested at the age 

of 63 days. The panel was laid up in freezing weather.

Test. Firing started at 9.14 a. m. February 1, 1907, and continued 2 hours and 2 minutes, after which the panel was cooled in 

the air without quenching. The fire was apparently uniform over 

the entire panel.
28 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

FIGURE 6. Diagram showing temperature conditions in the furnace and on the back of panel 6. Temperature: Maximum, 28°; minimum, 17°; mean, 22°. Relative humidity: 7 a. m., 92; 7 p. m., 100. Direction 

of prevailing wind, southeast.
U. S. GEOLOGICAL 

A. PANEL 6, CEMENT MORTAR BUILDING BLOCKS, DURING DISMANTLING. B. FACE 
BESULTS OF TESTS. 29

There was no cracking or spalling up to 70 minutes, when the block 

on the left-hand side of the panel in the eighth row cracked vertically 

on the back close to the center web on the outer edge. No crack on 

the fired side or face of this block could be detected. During the 

remainder of the test no other feature of importance was observed.

Curves showing the variation of the temperature throughout the 

test are given in figure 7.

Results. Plate XI, B, is reproduced from a photograph of the face 

of the panel after the test; Plate XII, A, from a photograph of the 

panel during dismantling. On removing the door from the furnace 

two of the blocks were found to be cracked. As the cooling proceeded irregular hair cracks developed-on the face of all the blocks, 

but were most pronounced on the 1:8 damp blocks. In the 1:2 blocks 

the cracks were very fine and apparently did not penetrate to any 

great depth. After the door had cooled for several hours cracks 

developed in each tier, running vertically through all the blocks. In 

the left-hand and center tiers the cracks were to the right of the 

center web, while in the right-hand tier they were on the left of the 

center web. The surfaces of the 1:8 blocks were found to be so soft 

that they could be brushed away with the finger to a depth of about 

J inch, difference in consistency having had little effect. The 1:2 

blocks were considerably harder. The surfaces of the blocks were 

apparently affected by the heat and were discolored from a depth 

of 1 inch to 1£ inches in the case of the 1:8, from.f inch to 1J inches 

in the 1:4, and from $ to 1 inch in the 1:2 blocks. The blocks of 

wet consistency were apparently in better condition than those of 

damp and medium consistency, but the difference was slight.

On dismantling the wall, it was found that none of the blocks were 

intact, all having cracked across the webs. In nearly every case the 

crack across the web was near the face, but in one or two cases it 

was near the back, the web remaining attached to the face.

The strength tests of the. fragments of these blocks are given in 

Table 7.

PANEL 8 (Mortar Building Blocks).

Material. Panel 8 consisted of one-piece single-air-space blocks 

made in the same manner and of the same proportions and consistencies as those previously tested. They were stored in a moist 

room in St. Louis 35 days and in Chicago 26 days, and were tested 

at the age of 64 days. The panel was laid up in freezing weather.

Test. Firing started February 4, 1907, and continued for 2 hours 

and 1 minute, after which the panel was cooled in air without the 

application of water. The fire was uniform and under good control.'
30 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

7X/ff

FIGURE 7. Diagram showing temperature conditions in the furnace and on the back of panel 7. Temperature: Maximum, 37°; minimum, 27°; mean, 32°. Relative humidity: 7 a. m., 91; 7 p. m, 85. Direction of prevailing wind, southwest.
U. S. GEOLOGICAL SURVEY 

A. PANEL 7, CEMENT MORTAR BUILDING BLOCKS, DURING DISMANTLING. II. FACE OF PA
RESULTS OF TESTS. 31

In 15 minutes the right-hand block in the third row bulged at the 

center, projecting about f inch, but no cracks were visible. At 20 

minutes, however, a vertical crack developed at the center, and the 

block bulged out about 1 inch. At 22 minutes'the block in the center 

of the third row spalled on the lower edge to a depth of about f to 1 

inch, and the spalling extended diagonally toward the right-hand 

corner, about one third of the surface becoming loose. The spalling 

then extended toward the left-hand side, and a piece about -| inch 

in depth and 2 inches wide on the left of the block came ofT. At 27 

minutes the block in the center of the second row spalled on the left 

side, after which the entire surface became loose and fell off. At 

this time the right-hand block in the third row, first mentioned,' 

bulged about 2 inches at the center, and the surface fell off to a depth 

of about 1 inch. The fresh surface exposed was comparatively smooth, 

indicating that a seam may have formed in the manufacture of the 

block. At 30 minutes the center block in the sixth row spalled, the

crack starting at the center and extending in both directions toward 

the ends. A portion about 6 inches square and £ inch deep at the 

center fell off. At 45 minutes the block in the center of the second 

row, above mentioned, bulged out to about £ inch, and the remaining 

portion of the face fell off. At 62 minutes the block in the second 

row center bulged to the extent of about f inch, and the remaining 

pieces of the face on the right-hand side fell off. The control of the 

furnace became difficult owing to the clogging of the burners by the 

fallen pieces. At 70 minutes the block in the center of the third 

row, before mentioned, spalled considerably more, and a small piece 

to the left of the center at the bottom fell off. During the remainder 

of the firing no further changes were noted.

The temperature curves are shown in figure 8.

Results. Plate XII, B, shows the face of the panel after cooling 

in air; a photograph of the back showed no noticeable damage. 

Plate XIII, B, shows the condition of the blocks while being removed 

from the panel. On cooling, irregular hair cracks were found over 

the surface of the blocks, which were largest and most numerous on 

the 1: 8 blocks. No vertical cracks were observed. The surfaces of 

most of the blocks, as may be seen in the photographs, were found 

more or less spalled, especially the 1:8 mixtures. The surfaces could 

be easily broken off on the 1:8 blocks. The -1:4 blocks were not so 

badly spalled, but the surfaces could be crumbled with the fingers. 

The 1:2 damp blocks were slightly spalled on the edges. The 1:2 

medium and wet blocks showed no signs of spalling, but to a depth 

of I inch the faces were soft. The concrete was discolored by heat 

to a depth of 1£ to If inches in the 1: 8, f inch to 1£ inches in the 1: 4, 

and £ to 1 inch in the 1:2. The different consistencies of any one 

proportion suffered about equally.
32 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

T/ME //V M/Aft/r£S

FIGURE 8. Diagram showing temperature conditions in the furnace and on the back of panel 8. Temperature: Maximum, 17°; minimum, 2°; mean, 8°. Relative humidity: 7 a. m., 88; 7 p. m., 90. Direction of prevailing wind, northwest.
U. S. GEOLOGICAL SURVEY

A. FACE OF PANEL 9, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING 

AND QUENCHING.

S. PANELS, CEMENT MORTAR BUILDING BLOCKS, DURING DISMANTLING.
U. S. GEOLOGICAL SURVEY 

A. BACK OF PANEL 9, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING 

AND QUENCHING.

11. PANEL 9, 
EESULTS OF TESTS. 33

On dismantling the panel, it was found that every block had failed 

across the web. As a rule the failure was near the face, but one or 

two webs cracked off at the back and remained attached to the fired 

side. In the case of one block the face cracked across its center web, 

one half coming loose from the web and the other remaining attached 

to the web on the other end of the block. The small linen marking 

tags, one of which was fastened against the back of each block in one 

of the core holes, were not damaged at all by the test. Three of 

these tags may be seen in Plate XIII, B.

The strength tests on the fragments of these blocks are given in 

Table 8.

PANEL 9 (Mortar Building Blocks).

- Material. Panel 9 consisted of two-piece blocks made in the same 

way and of the same proportions and consistencies as those previously tested. They were stored in the moist room in St. Louis 32 

days and in Chicago 29 days, and were tested at the age of 64 days.

The face of the panel was laid up in three tiers without breaking the 

joints, while the back was laid up with two tiers of whole blocks and 

two tiers of half blocks on each side: This was necessary in order that 

the blocks might be staggered to bond them. The views of the face 

and back of the panel (Pis. XIII, A, and XIV, A} show the arrangement of the blocks. The panel was laid up in freezing weather.

Test. The fire was started at 9.16 a. m., February 7, 1907, and 

continued for 2 hours and 1 £ minutes, after which water was applied 

for 5 minutes at a temperature of 36 ° F. A fairly uniform fire was 

obtained from the start.

For 20 minutes there was considerable snapping. In 60 minutes 

the right-hand block in the third row spalled at the outer edge. At 

78 minutes the right-hand block in the sixth row spalled at the center 

and small pieces cracked off. No further change was observed 

during the remainder of the test.

The temperature curves are given in figure 9.

Results. Plate XIII, A, shows the face and Plate XIV, A, the 

back of the panel after the test, and Plate XIV, B, the condition of 

the blocks during removal. On removing the panel from the furnace 

the blocks appeared to be smooth and no cracks were noticeable. 

After the application of the water all the blocks were cracked through 

on each side of the center webs with the exception of the 1: 2 mixtures 

on the bottom row. The surfaces were rough and pitted and washed 

away from £ to £ inch on the 1:2 blocks, from £ to f inch on the 1: 4 

blocks, and from 1 inch to 2 inches on the 1:8 blocks.

On dismantling the wall it was found that all the blocks had 

cracked away from their webs or the blocks had cracked on either 

73087 Bull. 370 09 3
34

Ret urn wir e burnt d off '

FACE OF

2

FURNACE

WATER PYROMETER

BACK OF PANEL

T/ME IN MINUTES

FIGURE 9. Diagram showing temperature conditions in the furnace and on the back of panel 9. Temperature: Maximum, 24"; minimum, 16°; mean, 20°. Relative humidity: 7 a. ni., 95; 7 p. m., 85. Direction 

of prevailing wind, southeast.
U. S. GEOLOGICAL SURVEY 

A. FACE OF PANEL 10, CEMENT MORTAR BUILDING BLOCKS, AFTER 

COOLING IN AIR.

£. BACK OF PANEL 
EESULTS OF TESTS. 35

side of the web, leaving a small piece of the face of the block attached. 

The webs of two or three of the blocks on the back of the panel were 

also cracked off. The 1:8 mixtures were badly crumbled and broken 

into small pieces when taken from the wall. This was true to a 

considerable extent in the 1:4 blocks, while the 1:2 blocks were not 

broken except at the webs. The blocks composing the back of the 

wall were apparently undamaged except for one or two cracked webs. 

The results of the strength tests are given in Table 9.

PANEL 10 (Mortar Building Blocks).

Material. Panel 10 was made of two-piece blocks exactly like 

those tested in panel 9, but was not subjected to the quenching after 

the fire test. The blocks were stored in the moist room at St. Louis 

28 days and at Chicago 32 days, and were tested at the age of 63 days. 

The panel was laid up in freezing weather.

Test. Firing was started at 2.11 p. m., February 11, 1907, and 

continued for 2 hours and 3 minutes, after which the panel was 

cooled in air, without the application of water. The fire was fairly 

uniform, but not as hot at the top as at the bottom and center.

In 8 minutes snapping and cracking was observed. At 12 minutes 

the second block in the second row spalled at the center, the cracks 

running off at the edges on all four sides. A small piece about 4 

inches long and \ inch thick fell out on the top edge. The righthand block in the third row spalled from a depth of about 2 inches 

along the edge to a depth of about \ inch at the center. The lefthand block in the sixth row spalled and a piece 9 inches long, \ to f 

inch thick, and the width of the block, fell out. At 70 minutes steam 

began to come through the joints, especially at the top. No further 

change was observed.

The temperature curves are shown in figure 10.

Results. Plate XV, A and B, shows the face and back of the panel 

after the test, and Plate XVI, A, the condition of the blocks during 

the dismantling. On removing the panel from the furnace it was 

found that, with the exception of the blocks that had already spalled, 

the surface was comparatively smooth. In about 5 minutes many 

hair cracks developed over the surface of the blocks. They were 

more pronounced in the lean mixtures than in the rich ones. As 

cooling progressed these cracks became more pronounced and covered 

more of the surface. Vertical cracks running along the webs were not 

present in this panel. The surfaces of the blocks were found to be 

very soft, especially in the 1:8 blocks, which could be easily rubbed 

away with the finger. In the 1:2 blocks the surface could be easily 

scratched with a tool to the depth of £ inch, in the 1:4 blocks to a
36 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

900 

800 

700 

600 

500 

400 

300 

E0t> 

/00 

0

1000 

900 

800

?ff° 

600

-500

300

200

6___,3,

2,4,5 '

.8

"2

f>»Cf

 >a

FURNACE

2 4

1300 

f200 

//<?<?

mo

300 

800 

700 

 00 

500 

<WO 

300 

30 

20 

/O 

0 

-10

FIGURE 10. Diagram showing temperature conditions in the furnace and on the back of panel 10. Temperature: Maximum, 33°; minimum, 18°; mean, 26°. Relative humidity: 7a.m., 71; 7p.m., 64. Direction of prevailing wind, south.

iy>»7-£^ PYROMETER

BACK OF PANEL
U. s. GEOLOGICAL SURVEY 

PANEL 10, CEMENT" MORTAR BUILDING BLOCKS, DURING DISMANTLING. 11. FACE OF PA
KESULTS OF TESTS. 37

depth of I inch, and in the 1:8 blocks to a depth of 1£ inches. The 

consistencies apparently had little to do with the behavior of the 

materials.

On dismantling the panel it was found that the blocks had all 

cracked across the webs, and in nearly every case across the face 

near the webs. The blocks were not as a rule broken in small pieces, 

as was the case (in panel 9) where the water was applied, but the 

surfaces were easily broken away from the remainder of the material. 

The blocks composing the back of the panel were unaffected, as far 

as could be observed, and only one or two of the webs were cracked off.

The strength tests of the fragments of these blocks are given in 

Table 10.

PANEL 11 (Brick).

Material. Panel 11 consisted of hard-burned clay bricks of good 

quality. These bricks were of a light salmon color and contained 

scattered small lime nodules, which made small black spots at the 

surface. The physical properties of the bricks are given in Table 11. 

In this table the transverse strength of the bricks before firing, the 

compressive strength of the bricks before firing and after firing, the 

compressive strength after being immersed in water 48 hours before 

firing, and the percentage of moisture absorbed in 30 minutes, 4 hours, 

and 48 hours are given.

The panel was built up as a standard 12-inch wall, with headers 

every seventh row, cement mortar being used.

Test. The test was made on February 15, 1907, and the firing 

continued 2 hours and 1 minute, after which the panel was quenched 

in water for 5 minutes, the water being at a temperature of 36° F. 

The fire was uniform over the entire panel.

In 15 minutes there was considerable snapping, which lasted 5 minutes. No cracks or chipping of the bricks was noticed at this time. 

At 25 minutes it was noticed that two or three of the bricks had pitted 

and that small pieces of the surfaces had split off, showing small lime 

nodules, which had probably expanded and burst. These pits were 

J to f inch deep. At 75 minutes part of the faces of two bricks 

cracked off and exposed lime nodules about £ inch in diameter. No 

further changes were noticed. >

In removing the door a delay of about 3 minutes occurred from 

the time the fire was shut off until the water was applied, owing to 

the door's sticking. The 12-inch brick panel loaded the frame somewhat beyond its capacity, so that the counterweights were not heavy 

enough to draw the door out. In prying the door from the furnace 

with a crowbar it was severely shaken, but apparently none of the 

bricks were cracked by the shaking. When the door was halfway
38 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

JOOO 

3W 

800 

700 

600 

500 

400 

300 

200

1000

800

S00 

400 

300 

200

/oo

ia__ is.

' 8

FURNACE

/200

800

700

600

SffO

400

JO

20

/O

O

-/o

2.

WATER PYROMETER

BACK OF PANEL

FIGURE 11. Diagram showing temperature conditions in the furnace and on the back of panel 11. Temperature: Maximum, 50°; minimum, 25°; mean, 38°. Relative humidity: 7 a. in., 76; 7 p. in., 61. 

Direction of prevailing wind, southwest.
RESULTS OF TESTS. 39

out, the attempt to move it farther was abandoned, and the water 

was applied to the half of the panel which stuck out from the furnace. The portion of the panel which was subjected to the stream 

of water is shown to the right of the vertical line in Plate XVI, B:

The temperature curves are given in figure 11.

Results. Plate XVI, B, shows the face of the panel after the test. 

About 18 or 20 per cent of the bricks were split and small pieces of 

the surface were washed away. After cooling, 60 or 70 per cent of 

the bricks were found to be cracked and split sufficiently to permit 

picking off portions. In most cases this splitting extended into the 

brick from $ inch to 1£ inches. Where water did not strike directly 

upon the panel, the bricks were not so badly broken, and from only 

a small percentage of them could portions be picked.

On dismantling the panel, however, it was found that about 60 

per cent of the bricks not exposed to the water were cracked, but 

the depth of these cracks was not as great as in the bricks exposed 

to the water. In nearly every crack a lime knot was found at the, 

bottom. The bricks on the back of the panel and the fillers were 

apparently unaffected, and the mortar holding these two layers 

together was apparently as hard as before the test. The mortar on 

the face was washed a,w&y about $ inch.

PANEL 12 (Brick).-

Material. The face of panel 12 was composed of hydraulic-pressed 

bricks of a dark-red color, uniform in size,, with square edges and 

corners. The surfaces were fine grained and free from knots and 

cracks. The back of the panel was composed of common bricks 

taken from panel 11. The bricks were laid as an 8-inch wall, with 

blind headers every sixth row, in cement mortar, the faces being 

laid in lime putty, as is customary with this class of brick. The 

panel was frozen when the test began.

The physical tests of these bricks are given in Table 12.

Test. This panel was fired February 19, 1907, for 2 hours and 1 

minute, and cooled by quenching with water for 5 minutes, the water 

being' at a temperature of 36° F. At the start the fire was well distributed and of a uniform color throughout.

In 15 minutes no snapping had been noted. During the entire 

test no cracking or spalling of the bricks could be observed. The 

heat was apparently well distributed except that there was a deposit 

of soot on the lower and central parts of the panel.

Curves showing the variations in temperature are given in figure 12.

Results. Plate XVII, A, shows the face of the wall after the test. 

On removal from the furnace one-third of the bricks were badly discolored. Only seven were seen to be cracked or pitted before the 

application of the water, and these defects were on the corners and
40 PIKE RESISTANCE OP VARIOUS BUILDING MATERIALS.

T/ME //v w/wres

FIGURE 12: Diagram showing temperature conditions in the furnace and on the back of panel 12. Temperature: Maximum, 45°; minimum, 32°; mean, 38°. Relative humidity: 7 a. m., 70; 7 p. ru., 53. 

 Direction of prevailing wind, west.
U. 8. GEOLOGICAL SURVEY

A. FACE OF PANEL 12, HYDRAULIC PRESSED BRICK : AFTER FIR::; I AND 

QUENCHING.

]!. FACE OF 
EESULTS OF TESTS. 41

represented a very small area of the bricks. After quenching with 

water about 18 per cent of the bricks were cracked through. None 

of them except those above mentioned were found to be spalled. 

After the test the wall was found to be apparently sound, though 

smoke stained. It could have been left standing and the injured 

bricks replaced by new ones without impairing its strength.

On dismantling, about 70 per cent of the bricks were found to be 

apparently sound.

PANEL 13 (Tile).

Material. Panel 13 consisted of semiporous glazed building tile 

(figure 13), of a light-brown color, but of several shades. The webs

FIGURE 13. Sketch of glazed building tile used in panel 13.

of the tiles were more or less cracked and checked, especially where 

they joined .the faces. The webs were very small and apparently 

did not prevent this condition of affairs." The faces were more or 

less rough and warped.

The tiles were laid on an 8-inch face, in cement mortar, with their 

long dimension in the horizontal plane. The joints were about £ 

inch and were broken. This exposed an 8-inch face to the fire. 

The panel was laid up in freezing weather.

Tests. The panel was fired February 26, 1907, for 2 hours and 1 

minute and quenched with water for 5 minutes, the water being at a
42 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

temperature of 36° F. An even fire was obtained at the start, and 

the fire was about uniform over the entire panel. No crackling or 

snapping was observed at any part of the test.

In 30 minutes a tile in the ninth row, third from the left side, 

split horizontally just under the center web. At 50 minutes a tile 

in the center of the eighth row spalled on the surface and a small 

piece (about 2 inches) came off. During the remainder of the test 

no further changes were observed.

The temperature curves are given in figure 14.

Results. Plates XVII, B, and XVIII, A, show the face and back 

of the panel after quenching. On removing the panel from the furnace none of the faces were apparently cracked, but in the quenching 

about 45 per cent of the faces fell off. During the first 2 minutes of 

the water treatment the tiles snapped and crackled appreciably, but 

not until about 2 minutes had elapsed did any of the faces actually 

fall from the panel.

After cooling, it was found that about 80 per cent of the tiles were 

badly cracked; on gently tapping those that remained in place the 

faces came off many of them. The faces that remained in place 

were found to be badly cracked, but firmly attached. The surfaces 

of the tiles had the same appearance as before the fire, except that 

small irregular hair cracks covered the entire face. The material 

comiposing the face could be easily broken in the hand.- In nearly 

every case the webs failed near the fired face. In a few cases the 

failure was diagonally across the web where the web joined the center 

web. The back of the panel was apparently uninjured, and in but 

few cases were cracks observed in the webs lying in a vertical plane. 

The mortar was washed out of the joints from 1 inch to 3 inches deep, 

and between a few tiles it was entirely washed out so that the water 

passed through the joints and ran down the back of the panel.

PANEL 14 (Mortar Building Blocks).

Material. Panel 14 consisted of 27 ''typical Portland" cement and 

slag-sand mortar one-piece single-air-space blocks made of a medium 

consistency of 1:1^,1:2i, and 1:4 mixtures. The specimens were 63 

days old when tested. They were cured in a moist room and sprinkled 

twice daily for 14 days and were then cured in air, being protected 

from, the sun, for 49 days. The blocks were laid in fire clay with the 

joints not broken. This was done to avoid cutting the specimens to 

make them fit the door.

Test. The panel was fired on May 23, 1907, for 2 hours and 2 

minutes and was cooled by the application of water at 50° F. for 5 

minutes. One minute elapsed between the time of removing the 

door from the furnace and the application of the water. The temperature of the furnace was even from the start. Curves showing
U. S. GEOLOGICAL SURVEY

,1. BACK OF PANEL 13, BUILDING TILE, AFTER FIRING AND QUENCHING. B. FACE OF P
RESULTS OF TESTS, 43

T/ME //V MMl/r£S

FIGURE 14. Diagram showing temperature conditions in the furnace and at the back of panel 13. Temperature: Maximum* 37°; minimum, 26°; mean, 32°. Eelative humidity: 7 a. m., 79; 7 p. m., 78. 

Direction ofprevafllng wind, southeast.
44 PIKE RESISTANCE OF VARIOUS BUILDING MATERIALS.

the various temperatures recorded during the test are given in 

figure 15.

In 13 minutes the blocks began to turn dark red. No snapping 

was noted throughout the test. At 55- minutes the blocks in the 

second row on the right end cracked in lower left corner, and a small 

piece, about $ inch thick by 2 square inches in area, fell out. During 

the remainder of the test no apparent change occurred.

Results. On removal of the panel from the furnace, before the 

water was applied, there were no cracks or spalled places observed. 

The face of the panel was badly smoke stained, especially at the 

bottom and about halfway up the panel at the center. The effect of 

the water was to wash the spalled portion away to the depth of about 

£ to f inch on the 1:1$ mixtures, $ to f inch on the 1:2-| mixture, 

and $ to f inch on the 1:4 mixture. The resulting surfaces were 

rough and pitted, but were nearly as hard as the unaffected portions 

of the block. That the 1:1$ proportion had not been as well mixed 

as the others was shown by small lumps of cement appearing on the 

surface.

Plate XVIII, B, shows the panel face after 'firing, and Plate 

XIX, A, the back of the panel after firing. Plate XIX, B, is repro7 

duced from a photograph taken while dismantling the panel.

Only one block, a 1:4 mixture, had split through the webs; the 

cracks developed across the webs close to the fired side. The face 

of this block which had been exposed to the fire was apparently uncracked and was lifted from the wall intact. The remainder of the 

blocks were strong enough to be handled and were later tested for 

transverse and compressive strength.

PANEL 15 (Mortar Building Blocks).

Material. Panel 15 consisted of 27 mortar blocks made on a 

single-air-space block machine. A medium consistency was used for 

the three mixtures, 1:2, 1:4, 1:8, "typical Portland" cement and 

Meramec River sand being the ingredients. The specimens were 

cured in a moist room for 10 days and in air protected from the sun;s 

rays for 53 days, making them 63 days old when tested.

Test. The panel was fired at 9.12 a. m. May 27, 1907, for 2 hours 

and 1 minute, at the end of which time a stream of water at 51° F. 

was played on the hot wall for 5 minutes. One minute elapsed 

between the time the furnace was shut down and the application of 

the water;

The blocks were laid in fire clay without breaking the joints. The 

temperature of the whole panel was quite uniform from the start. 

No snapping was observed during the test and no spalling or cracking 

was observed up to the time of the application of water.
U. S. GEOLOGICAL SURVEY 

A. BACK OF PANEL 14, CEMENT MORTAR BUILDING BLOCKS, AFTER 

FIRING AND QUENCHING.

£. PANEL 14, CEME
RESULTS OF TESTS. 45

800 

700 

600 

SOO 

<!00 

300 

ZOO 

/OO 

tf

/WO

900

Q 800

ft*

S 60°

SOO

FACE OF PANEL

FURHACE

300

20° 

/Off

^ 

/zoo

//ffO

MOO

900

800

700

600

SOO

400

300

200

30

20

/0(

0

rIO

PYROMETER

OF PANEL

7/W //V M//MTES

FIGURE 15. Diagram showing temperature conditions in the furnace and at the back of panel 14. Tern 

perature: Maximum, 51°; minimum, 46°; mean, 48°. Relative humidity: 7 a. m., 97; 7 p. m., 94. Dlrec 

tion of prevailing wind, northeast.
46 FIEE RESISTANCE OF VAKIOUS BUILDING MATERIALS.

Curves showing the variations of temperature observed during the 

test are given in figure 16.

Results. In removing' the panel from the furnace it failed to slide 

clear, and consequently a strip about 10 inches wide on the left side 

was not exposed to the direct stream of water. The 1:2 mixture 

spalled to a depth of about | to \ inch, the 1:4 to about f inch to 2 

inches, and the 1:8 about the same as the 1:4. On all. the 1:2 specimens portions of the surface remained intact, but were covered with 

small hair cracks and could be easily crumbled with the fingers. 

The remainder of the blocks were hard, but in every case they were 

badly cracked and pitted. This was particularly true of the 1:8 

mixtures. One block of a 1:8 mixture, in the seventh row, right-hand 

side, was cracked on the back side. This was the only specimen 

which cracked in this manner in any of the tests on mortar blocks.

Plate XX, A, shows the face of the wall after firing, and Plate 

XX, B, shows the condition of the wall while being dismantled. On 

taking down the panel it was found that all the blocks except one 1:8 

block had cracked across the web at the fired side. One web of this 

block was cracked on the fired side, while the other cracked across to 

the back side of the .block. The faces of all the 1:8 blocks crumbled 

and fell to pieces when removed from the panel, and a few of the 1:4 

blocks were found to be cracked through the fired side. This was 

also found to be the case with one of the 1:2 blocks. The portions 

of the blocks on the fired side were seemingly intact and hard, but on 

gentle tapping could be broken into very small pieces. The back 

surfaces and the attached webs were as hard as before the fire treatment, and there was apparently no change in their condition.

PANEL 16 (Mortar Building Blocks).

Material. Panel 16 was composed of 27 one-piece single-air-space 

building blocks, 9 each of 1:2, 1:4, and 1:8 "typical Portland" 

cement and Meramec River sand. These blocks were tested when 63 

days old, having been cured in a moist room for 3 days, being sprinkled 

twice daily, in air under cover for 7 days and exposed to the weather, 

but protected from the direct rays of the sun for 53 days.

Test. The fire was started at 1.19 p. m. May 28, 1907, and continued for 2 hours and 1 minute. Immediately on removing the 

panel from the furnace it was quenched by a stream of water at 51° 

F. for 5 minutes. No snapping was observed during the test.

In 40 to 45 minutes a black spot was observed on the right side 

and about the middle of the panel, indicating a drop in temperature 

at this point. At 60 minutes the burner on the right side of the furnace became clogged and caused the temperature on that side of the 

panel to drop a little. The black spot above mentioned had disappeared in the interval. At 70 minutes the furnace was readjusted
U. S. GEOLOGICAL SURVEY 

A. FACE OF PANEL 15, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING AND

QUENCHING.

11. PANEL 15, 
EESULTS OF TESTS. 47

FIGURE 16. Diagram showing temperature conditions in the furnace and on the back of panel 1,5. Temperature: Maximum, £2°; minimum, 38°; mean, 45°. Relative humidity: 7 a. m., 83; 7 p. m., 64. Direction of prevailing wind, northwest.
48 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

and the right-hand side of the panel was brought up to the normal 

temperature. No signs of spalling were noticed up to the time the 

panel was removed from the furnace.

Curves showing the variations of temperature observed during the 

test are given in figure 17.

Results. On taking the panel down it was found that all the blocks 

had cracked across the webs and that the faces of all the 1:8 mixtures were so badly cracked that these blocks could not be removed 

intact. On gently tapping the material it fell to pieces and crumbled 

very badly. Two or three of the 1:4 blocks behaved in a similar 

manner, but each half of the 1:2 specimens was removed intact. 

The back half of all the 'blocks was apparently unaffected and free 

from cracks.

Plate XXI, A, shows the face of the panel after the test. Plate 

XXI, B, shows the panel being removed from the door. On the 

application of water the face of the 1:4 and 1:8 blocks spalled to the 

depths of | to 1 inch and 1 inch to 2 inches, respectively. On two of 

the 1:2 mixtures part of the face was left apparently intact, but on 

examination it was found that this part crumbled easily in the hand. 

With the exception of the surface the remaining concrete was found 

to be quite hard. There were apparently no vertical cracks running 

through any of the blocks.

PANEL 17 (Concrete).

Materials. Panel 17 consisted of four kinds of concrete, as follows: 

A 1:2:4 medium consistency (10 per cent water) limestone crushed to 

pass a f-inch screen and be retained on a £-inch screen; a 1:2:4 medium 

consistency (21 per cent water) cinder containing 24.5 per cent of 

combustible material. These cinders were screened to pass a 1^-inch 

screen; a 1:2:4 medium consistency (9 per cent water)-granite 

crushed to pass a f-inch screen and remain on a J-inch screen; a 

1:2:4 medium consistency (9 per cent water) gravel screened to pass 

a f-inch screen and remain on a J-inch screen.

The sand and cement mixed with the above coarse aggregates were 

Meramec River sand and " typical Portland " cement. The specimens 

fired were sections of plain beams previously tested in the Government's structural-materials testing laboratories at St. Louis. -They 

measured 8 by 11 inches in cross section and varied in length from 

18 to 36 inches. The test pieces were laid in fire clay on their 8-inch 

side, thus exposing the 11-inch face to the fire. This arrangement 

permitted a section 22 inches high by 6 feet long of each material, 

except the limestone concrete, to be exposed to the fire in the same 

panel. Only one piece of the limestone concrete, about 20 inches 

long, was tested, as that was all of this character of concrete which 

could be obtained at the time the shipment was made from St. Louis.
U. S. GEOLOGICAL SURVEY

A. FACE OF PANEL 16, CEMENT MORTAR BUILDING BLOCKS, AFTER FIRING AND

QUENCHING.

S. PANEL 16, CEMENT MORTAR BUILDING BLOCKS, DURING DISMANTLING.
KESULTS OF TESTS. 49

eoo

700

600

500

400

300

200

900

^

§ SCO

\ 700 

b 600

h^

& 300

FURNACE

/oo

O 'Wo.

/100 

/000

900 

800 

700 

600 

SM 

WO 

300 

200

30\ 

20

WATER PYROMETER

BACK OF PANEL

FIGURE 17. Diagram showing temperature conditions in the furnace and on the back of panel 1C. Temperature: Maximum, 65"; minimum, 45°; mean, 55". Relative humidity: 7 a. m., 06; 7 p. in., 51. Direction of prevailing wind, southwest.

73087 Bull. 370 09 i
50 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS. -

Test. The firing was started at 10.52 a. m. June 7, 1907, and 

continued for 2 hours and 3 minutes, after which the panel was 

quenched with water for 5 minutes. The temperature of the water 

was 52° F.

At the start of the test the back of the panel was wet, owing to rain 

the night previous. The burners started with a fairly uniform 

temperature and under good control; the top was not as hot, however, 

as the lower part, of the panel. In 25 minutes a slight pitting was 

noticed on all four kinds of concrete and small pieces, about J inch 

deep and 1 inch in area, fell out from the faces. The cinder concrete 

developed bright red spots, from which small flames issued. These 

spots covered the greater part of the surface of the cinder concrete and 

were about 8 or 10 inches apart. At 45 minutes steam was noticed 

passing through the joints on the back of the wall. At 65 minutes the 

cinder concrete was quite badly pitted, though of a uniform color, the 

entire surface having attained the same color as the bright red spots 

before mentioned. A number of small bulges projected out from the 

wall about $ to \ inch. Pits developed as these bulging portions fell 

away. The limestone and gravel concrete were pitted all over to a 

depth of \ to £ inch.

Curves showing the variations of temperature observed during the 

test are given in figure 18.

Results. On the application of water portions of the surface of all 

four varieties of concrete washed away. The limestone'washed away 

from i to ^ inch, but the remaining surface was very smooth and the 

exposed stones showed the effect of calcination. The surrounding 

concrete, however, was apparently hard, free from cracks, and 

showed no signs of discoloration or calcination. The surface had very 

much the appearance of concrete which has been vigorously brushed 

while green.

The stone was discolored to a depth of about 1 inch. Back of this 

the stone did not show any signs of heat treatment. The material on 

the surface had a very dead sound when tapped gently with the 

hammer, but on the back side it had the usual metallic ring.

In the case of the gravel, where the mortar portion of the concrete 

was rather deep, the surface was still intact, but the greater portion of 

the surface was pitted and washed away to an average depth of 

| inch. The surface was very rough and the exposed pieces ef gravel 

were dark brown and very easily broken under a hammer. In 

several cases they were split and parts of the stone could be pulled out 

with the fingers. The particles of gravel in the concrete were discolored to a depth of about 4 inches. The mortar in this layer was 

apparently normal, and appeared as hard as that of the unaffected 

product. It was but slightly cracked on the surface only. Throughout all the pieces vertical cracks running back from the fired side
RESULTS OF TESTS. 51

/aoo

300

800

.700

600

500

4

f «

300

200

FACE OF PANEL

/oo

ii '1-6

300

800

-e

soo

400

FURNACE

200 

/OO

1000

T/ME //V M/NUTES

FrouRE 18. Diagram showing temperature conditions in the furnace and on the 

perature: Maximum, 56°; minimum. 50°; mean, 53°. Relative humidity: 7 

Direction of prevailing wind, northeast.

back of panel 17. Tema. m., 94; 7 p. in., 100.
52 FIBE RESISTANCE OF VARIOUS BUILDING MATERIALS.

were observed; they were about 4 to 10 inches apart and extended 

back from the face about 2 to 4 inches. They were nearly straight 

in direction and could be found on both the bottom and top of each 

beam. The face of the portion in which the gravel was discolored 

had a very dea,d sound when tapped with a hammer, while the back 

had a good metallic ring.

In the case of the granite there was a considerable portion from 

which the mortar surface had not been washed away. The remaining surfaces were washed away about £ to f inch. The exposed pieces 

of stone were slightly discolored, being lighter than the unaffected 

material, but in most cases were hard and broke but little more 

easily than the unheated ones. The mortar was soft and crumbled 

about 1-| inch. For about 3 inches in from the face the mortar had 

turned a light straw color, but was quite hard. For about 6 inches 

from the face the concrete had a whitish tinge, which indicated that 

the free moisture had been driven entirely out. This whitish layer 

was apparently as hard as the layer on the back. To a depth of 

about 2 inches the pieces of stone had a rather cloudy look.

Vertical cracks ran directly back from the face on both the top and 

bottom of the beam; they were from 2 to 6 inches apart and extended 

back from the face 4 inches. By tapping, the beams could be broken 

across these cracks. The face had a very dead sound when tapped 

with the hammer; the back had the usual metallic ring.

In the case of the cinder a part of the face was still intact after the 

application of water. However, it is very likely that the upper lefthand corner was more or less protected from the intense heat to which 

the remainder of the panel was subjected. On the other parts of the 

cinder concrete the spalling from the fire and water was from f to 1£ 

inches deep. The surface was rough and very badly pitted, although no 

cracks could be observed. For about an inch the concrete was black

and looked very spongy, because the particles of combustible material 

had been entirely burned out. In a layer about -| to f inch in depth, 

directly behind this spongy layer, the concrete was black and looked as 

if it had been badly smoked. The combustible material in the center of 

this layer was caked. Back of this layer was a strip 3 to 3J inches wide 

showing no discoloration, but the mortar, whiter than the normal 

concrete, indicated that the uncombined water had been driven away. 

The remainder of the beam was apparently normal.

Vertical cracks running back from the fired face were found in only 

two or three cases, and extended back only from 2 to 4 inches. The 

surface had a very dead sound and could be easily crumbled, while the 

back of the beam was unaffected and had the usual metalhc sound.

Plate XXII shows the face and the back after quenching.
U. S. GEOLOGICAL SURVEY

A. BACK OF PANEL 17, CONCRETE WITH DIFFERENT AGGREGATES, AFTER 

FIRING AND QUENCHING.

IS. FACE OF PANEL 17, CONCRETE WITH DIFFERENT AGGREGATES, AFTER 

FIRING AND QUENCHING.
RESULTS OF TESTS. 53 

PANEL 18 (Concrete).

Material. Panel 18 was made up of short lengths of plain granite 

concrete beams 8 by 11 inches in cross section and in lengths varying 

from 18 inches to 2£ feet. The concrete was a 1:2:4 mixture of 

"typical Portland" cement, Meramec River sand, and Missouri 

red granite, mixed to a medium consistency (about 9 per cent water). 

The stone was screened to pass a f-inch screen and be retained on a 

i-irich screen. The panel was laid up in fire clay with broken joints. 

The specimens were laid on their 8-inch side, thus exposing the 

11-inch face to the fire.

Test. The test occurred on June 10, 1907, and firing continued for 

2 hours and \ minute. After firing the face of the panel was 

quenched with water at 51° F. for 5 minutes.

In 15 minutes snapping was noted, which continued for about 5 

minutes. At 25 minutes hot water was forced back through the 

joints and washed off the fire clay, which held the back-wall thermometers in place. This water was considerably warmer than the 

back-wall surface, consequently the thermometers there attached 

showed unduly -high temperatures. At 40 minutes the top of the 

panel began to dry out, the bottom portion still remaining wet with 

the water which leaked through the joints. At 63 minutes a slight 

spailing was observed in several places, principally at the top of the 

wall. At 75 minutes the back-wall face of the panel had entirely 

dried out, but steam came through the joints on the top of the 

panel. During the remainder of the time no further change was 

noted.

Curves showing the variations in temperature observed during 

the test are given in figure 19.

Results. After quenching with water it was found that some portions of the surface of the concrete had spalled and had been washed 

away, while in other places the surface was nearly all intact and the 

mortar still adhered; but it was cracked, and crumbled easily in the 

fingers. The exposed particles of stone were found to be of a cloudy 

whitish color and quite hard, although more easily broken than the 

unchanged stone. The stone had whitened to a depth of about 1 inch 

and the mortar to about 3£ inches.

Vertical cracks running back from the fired face occurred about 

4 to 6 inches apart, and extended back from the face about 4 inches. 

By tapping with a hammer the beam could be broken where these 

cracks occurred. The surface had a very dead sound when tapped 

with the hammer, but the back was apparently normal.

Plate XXIII, A and B, shows the face and back of the panel after 

firing.
54 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

/MO

800 

700 

600 

SffO

FURNA

^\

dOO

WATER PYROMETER

600

BACK OF PANEf.

T/ME //V M/NV7ES

FIGURE 19. Diagram showing temperature conditions in the furnace and on the back of panel 18. Temperature:"Maximuin, 79°; minimum, 58°; mean, 08°. Relative humidity: 7 a. mv 78; 7 p. m., 79. Direction of prevailing wind, southeast.
U. S. GEOLOGICAL SURVEY 

J. FACE OF PANE:. ., GRANITE CONCRETE, /-,, B. BACK OF PAN
RESULTS OF TESTS. 55 

PANEL 19 (Concrete).

Material. Panel 19 was composed of similar-sized sections of 

gravel concrete beams, laid as described for panel 18. The mixture 

and consistency were the same as" in panel 18, being 1:2:4 medium 

consistency. The gravel passed a f-inch screen and was retained 

on a J-inch screen, and was of the Meramec flint variety.

Test. The test took place on June 11, 1907, at 2.25 p. m., and 

continued for 2 hours 3 minutes, followed by quenching with water 

at 53° F. for 5 minutes. At the outset the temperature at the top of 

the panel seemed higher than that at the bottom.

In 16 minutes water came through the joints on the back of the 

wall and ran down, washing away the fire clay holding the thermometer in place. Up to 25 minutes no snapping had occurred. At 45 

minutes the greater part of the surface of the concrete had spailed 

and pitted in small spots. These small pits exposed stones-which had 

probably cracked and expanded sufficiently to force the mortar away 

from the face. At 80 minutes the pitting and cracking away of 

small portions of the surface was very general over the lower and 

left-hand side of the panel. No* further change was noted and the 

surface of the panel seemed to resist any further pitting.

Curves showing the variations in temperature observed during the 

test are given in figure 20.

Results. Plate XXIV, A and B, shows the face and back of the 

panel after the test. On the application of water the surface washed 

away on the lower and left side of the panel, while on the upper and 

right side the surface was less severely affected. Particles- of gravel 

were discolored to a depth of 2£ to 3 inches1', turning a dark reddishbrown, while the mortar surrounding them remained about normal. 

Many gravel stones on the surface had split, but were apparently as 

hard as the sound ones. Vertical cracks from 2 to 4 inches apart 

ran back from the face to a distance of about 3 inches. These cracks 

. could be opened up by tapping, and the layer containing the discolored 

gravel could be cracked off from the surface of the beam with a 

hammer. The back portions of the beams were not affected and had 

a good solid metallic ring, while the fired side sounded dead when 

struck with a hammer. Where the mortar had not been washed 

away the surface was covered with fine hair cracks and the material 

could be crumbled in the fingers. The gravel under this coating 

of mortar was not cracked, but was somewhat discolored.

PANEL 20 (Concrete).

< Material. Panel 20 was made up of^l^-inch to 2^-foot lengths of 

cinder concrete beams, 8 by 11 inches in section, laid on the 8-inch 

face. The concrete was .of "typical Portland" cement, Meramec
56 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

MOP

900 

SOO 

700 

600 

SOO 

400 

300 

ZOO 

/OO 

0

/ooo

900 

800

600 

SOO

200 

2ff0 

/OO 

G 

H00

mo 

soo 

soo

700 

600 

SOO

-too

300 

2OO 

/ffO

1

SO 

 M 

30

zd

I

/3

/

>I.Z,3A5,6

10

1

I

/

1

7,8,9,/0

; 7

/

J 

2 / 

/

6

'5

10 

J

7

/ /

9

8

>

/

/

 1 ^

5

" ^

$

6

 -^

^

f9

8

/

^

) <

^

i 3

.(0 '

'7 _J^

8 

'9

^-^

'

_ ^-^

S

tf^&

J V

i!» '

2^

6

FACE

8

W>

^ -^

,

9

7a H

«.

FU

k

N

1TER

r~""

?ACK

,3

^~<

2

OF P

'10

'9

^ H

,7 «' '8

RNAC

X\

6

)t- ^

 /,3.

>J/VfZ.

(0

>z <

9

E

JT

^

5

<S

l'2

,/o

^

'7

8

y^s

PYROMETER

-i > - 

~~~- {

OF PANEL

I 4

5 '

3

''

10

7

8

9

^.,

' 6

S

!T '

 3

'1

10

,7

>- -«

8

.9

-

___ ^<

z ««2

r^-

^ 30

/a 'l

10

109 

l? 70

£ ^8

3o

'3

-o

^

> °

FIGURE 20. Diagram showing temperature conditions in the furnace and on the back of panel 19. Temperature: Maximum, 78°; minimum, 59°; mean, 68°. Kelative humidity: 7 a. in., 75; 7 p.m., 90. Direction of prevailing wind, west.
U. S. GEOLOGICAL SURVEY

4. FACE OF PANEL 19, GRAVEL CONCRETE, AFTER FIRING AND QUENCHING. 21. BACK OF PAN
RESULTS OF TESTS. 57

River sand, and soft coal cinders, containing 24.5 per cent of combustible material. The proportions were 1:2:4 by volume. The 

cinders were screened to pass a 1^-inch screen and be retained on a 

J-inch screen. The top row in the panel was composed of granite, 

gravel, and terra-cotta tile and was put in merely to fill up the space 

due to a shortage of the cinder specimens.

Test. The panel was fired at 11.54 a. m. June 17, 1907, for 2 hours 

2f minutes, and was cooled by quenching with water at 57° F. for 

5 minutes.

In 7 minutes the concrete snapped' quite badly and one or two 

small explosions forced oft' small portions of the surface of the beams. 

No. 7 couple was more exposed than usual on account of the fire-clay 

mounting being cracked off by a piece of the surface of the cinder 

concrete which blew across the furnace. At 18 minutes all the cinderconcrete surface had begun to pit and pieces about 1 inch in area 

and & to J inch in depth fell out. ,A piece on the second row from 

the bottom, about 6 inches square and $ inch in depth, was forced 

off with considerable violence, exposing several pieces of unburned 

coal. This was followed by several small explosions, and a piece of 

the surface about 8 inches square and \ inch thick, just adjoining 

the above-mentioned piece; came off. Small bright-red spots from 

which flames issued were distributed over the surface. At 30 minutes the burners became more or less clogged from the small pieces of 

concrete which had fallen into them. This somewhat impaired the 

control of the furnace. At 40 minutes the spalling became general 

over the surface and many small pieces of concrete continued to fall 

from the panel. The color became bright red and the small spots 

were no longer visible.

Curves showing the variations in temperature observed during the 

test are given in figure 21.

Results. On removal of the door it was found that the greater 

part of the surface of the cinder concrete had cracked off; during the 

application of water a considerable portion of the surface was washed 

away, apparently to about the same depth ($ inch). A very small 

portion of the face of each beam was still intact, but this portion was 

porous and crumbled easily in the hand. The surface was rough and 

the concrete was spongy and black to a depth of about 1 inch. The 

mortar in this layer was easily crumbled in the fingers. A layer 3 to 

4 inches thick back of this was discolored, being turned almost black, 

and the particles of combustible material were practically turned to 

coke. The mortar in this layer was apparently hard. The remainder of the beam was about normal.

Plate XXV, A and B, shows the face and back of the panel after 

testing. A few vertical cracks running back from the face of the 

beams were not very regular and did not open up readily when
58 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

_^^s

&

/MO

900

3,10

700 

600 

SffO Si 4"1

« 300

ax. 

too

FURNACE

/200

ttoo

T/ME /N MINUTES

FIGURE 21. Diagram showing- temperature conditions in the furnace and on the back of panel 20. Temperature: Maximum, 91°; minimum, 70°; mean, 80°. Relative humidity: 7 a. m., 58; 7 p. m., 41. Direction 

of prevailing wind, southwest.
FACE OF PANEL 20, CINDER CONCRETE, AFTER FIRING AND QUENCHING. IS. BACK OF P
RESULTS OF TESTS. 59

tapped rather hard with a hammer. The face of the concrete crumbled when tapped, while the back gave a good sound metallic ring. 

The affected portion that is, a layer about 2$ inches thick could 

be separated from the unaltered portion by tapping on the edges of 

the piece.

PANEL 21 (Sandstone).

Material. Panel 21 consisted of pieces of cut sandstone, 7f by 4 

by 24 inches, laid on the natural bed in cement mortar, with the 

7-|-inch face to the fire. The joints were broken.

Test The panel was fired at 3.03 p. m. June 21, 1907. for 23 

minutes.

In 10 minutes the wall bulged in toward the fire at the center of 

the panel about 2 inches and at the edges about 1£ inches. No 

snapping was noted up to this time. At 19 minutes a vertical crack 

in the fifth row in the center gradually developed through the mortar 

joints and extended into the pieces in the third and seventh rows. 

At 21 minutes vertical cracks developed in the seventh row on the 

left side, about 8 inches from the edge of the panel, and rapidly 

extended the entire length of the panel. A crack simultaneously 

developed on the other side of the wall about the same distance from 

the edge, running vertically from top to bottom. At 23 minutes the 

panel unexpectedly collapsed, falling into the fire chamber. The 

failure occurred by reason of the joint in the fifth row opening and 

allowing the bottom portion of the panel to fall, forward into the 

chamber; then the top portion fell directly down. Although the 

panel appeared very weak, there was no snapping or crackling up to 

the time of the failure, and consequently the thermometers attached 

to the back side of the wall and thermal couples inserted through it 

were not removed. The failure carried these do^yn andjbroke all 

the thermometers and cold junction bottles. The thermal couples, 

fortunately, were uninjured.

Curves showing the variations in temperature observed during the 

test are given in figure 22.

Results. After the collapse it was found that in all the test pieces 

cracks had developed across the face vertically and extended back 

within about 1 inch of the back side. Horizontal cracks along the 

bedding of the stone also developed, and by falling the layers were 

broken into small but rather regular pieces. The test pieces that did 

not break in two were found to be warped from ^ to $ inch a.t the 

center, the bulging being toward the fired side.

The material was turned a light reddish brown to a depth of about 

f to 1 inch on the fired side. The surface was apparently as hard as 

before being subjected to the fire, and there was no evidence of 

spalling or pitting. The surface was, however, very badly cracked
60 .FIRE RESISTANCE OP VARIOUS BUILDING MATERIALS.

/ooo

900 

800 

700

T/lfl

400 

300 

£00 

/OO 

. & 

/OOO 

900 

SOO 

700

600 

SOO 

400 

300 

200 

/OO 

0 

/OOO 

900 

800 

700 

600

500

400 

300 

200 

100 

0 

60 

SO 

40

?(,

;

/! / '

/

* 1-6

'

/

[7,8

1

/

/

/

/

/

/

1

r ^

.

2 i

>6 :

^

4

'

i

'7

8

J.

/

/

;

/

/

f

4

6

1

,.

2

,7f £ 

8

i

)

Fail se/ afti r2l mi n.

FACE OF PANEL

FURNACE

WATER PYROMETER

BACK OF' PAN EL

v

^

I

I

T/ME M M/NUTES

FIGURE 22. Diagram showing temperature conditions in the furnace and on the back of panel 21. Temperature: Maximum, 88°; minimum, 07°; mean, 78°. Relative humidity: 7 a. in., 73; 7 p. in., 63. 

Direction of prevailing wind, southwest.
l OGICAL SURVFY

1. FACE OF PANEL 21, DRESSED SANDSTONE, BEFORE FIRING. B. PAN
U. S. GEOLOGICAL SURVEY

A. FACE OF PANEL 22, COMMON BRICK, BEFORE FIRING, 11. FACE Of 
RESULTS OF TESTS. 61

along the bedding of the stone, and also in lines vertical to this 

direction. No irregular hair cracks were observed. Plate XXVI, A, 

shows the face before testing. Plate XXVI, B, shows the wall after 

its collapse.

PANEL 22 (Brick).

Material. Panel 22 consisted of common St. Louis brick from the 

foundation of the briquetting machine at the Government's fueltesting plant at St. Louis, where they had been placed about three 

years before they were tested for their fire-resisting properties. 

Physical tests of the bricks are given in Table 13. The bricks were 

laid in cement mortar with |-inch joints in a standard 8-inch wall, 

and bonded every sixth row. It was decided that a 12-inch wall 

was too heavy for the apparatus.

Test. The panel was fired June 24, 1907. The duration of fire 

was 2 hours and 1 minute; then the panel was cooled by quenching 

with water for 5 minutes. The temperature of the water was 59° F. 

The test was started at 2.20 p. m. A good uniform fire was obtained 

at the start.

In 20 minutes a slight snapping was observed. At 30 minutes 

steam appeared through cracks on the back of the wall. At 50' 

minutes the end of one of the header bricks cracked and fell off. The 

piece was about 1 inch in depth. No further changes were observed 

up to the time of removing the panel.

Curves showing the variations in temperature observed during the 

test are given in figure 23.

Results. About 15 per cent of the faces of the brick cracked and 

washed off during the application of the water. After cooling, it was 

found that about 50 per cent of the faces were cracked and were 

easily pulled off with the fingers, or by prying gently with a screwdriver. The headers which seemed most damaged were split back 

about 1 inch. Some were cracked to a depth of 2^ inches. The faces of 

all the bricks were checked and cracked, and wherever a piece fell out 

it was usually about 1 incli in thickness. The entire wall was discolored to a depth of about 1 inch, the faces of the bricks turning 

almost black. The bricks on the back of the wall were apparently 

uninjured, no cracks being observed in any of them.

Plate XXVII, A, shows the face of the panel before firing and 

Plate XXVII, B, shows the face after quenching.

PANEL 23 (Granite Building Stone).

Material. Panel 23 was composed of blocks of building granite 

laid in cement mortar with broken joints.

Test. The test took place on June 26, 1907. The duration of the 

fire was 2 hours and ^ minute, after which the panel was quenched 

for 5 minutes with water at 57° F.
62 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

800

700

SOO 

400 

300 

100 

/OO

6- 4\ 3,6

2.4

FACE OF PANEL

_ { «3

SOO 

700 

600 

SOO 

4ffO 

300 

BOO 

/OO 

0

FURNACE

J300 

/ZOO

//oo

1000

300

800

700

600

SOO

400

300

60

SO

40

30

20

\

WATER PYROMCTCR

BACK OF PANEL

T/fiE /M MINUTES

FIGURE 23. Diagram showing temperature conditions in the furnace and on the back of panel 22. Temperature: Maximum, 80°; minimum, 69°; mean, 74°. Relative humidity: 7 a. m., 90; 7 p. m., 63. 

Direction of prevailing wind, southwest.
BESULTS OF TESTS. 63

The furnace started with a good, even temperature and in about 2 

minutes considerable snapping was heard, although no cracks 

appeared either on the face or on the back of the panel.

At 5 minutes it was observed that the wall had bulged inward 

toward the fire about £ inch and horizontal cracks were observed in 

the mortar joints at the sides and bottom of the panel. At 10 

minutes the wall had bulged 1£ inches. At 13 minutes a crack 

between the sill and the material in the panel had developed to about 

£ inch in width and extended the entire length of the panel. By 

this time the center of the door had bulged 1£ inches. Owing to this 

bulging it was feared that a collapse similar to that of panel 21 would 

be repeated. The thermocouples and thermometers were accordingly removed from the panel. At 17 minutes a block in the center 

of the seventh row began to spall, starting at the center of the block 

on the top and running diagonally to the lower left edge. The piece 

did not fall off. At 20 minutes the center of the panel had bulged 

!$ inches. At 22 minutes the furnace was shut down for about 1 

minute, in order that it might be more evenly adjusted. At 29 

minutes a vertical crack developed in a block in the seventh row on 

the back of the panel. Also a block in the third row on the lefthand side cracked vertically on the back near the center, followed 

by a vertical crack 6 inches from the outer end and another vertical 

crack 4 inches from the inner end. These cracks did not show on the 

fired side, but it is very probable that they extended entirely through 

the stone. At this time the panel had bulged 1||- inches. At 33 

minutes the seams at the side of the panel between the granite and 

the. frame of the door had opened to a width of f inch and extended 

the entire height of the wall. A vertical crack started in the lefthand block in the eighth row, about 8 inches from the inner end, 

developing on the back of the wall. At 35 minutes the wall'had 

bulged 2$ inches. Small vertical cracks noted in nearly all the 

pieces were gradually increasing in size, running vertically. It was 

rare that one of these cracks was directly over another, which would 

show that they were due to internal stress rather than to stress set 

up in the panel as a whole. At 40 minutes the back of the blocks 

became too warm for the hand to be placed on them. At this time 

the wall had bulged 2/F inches. At 48 minutes, on the back of 

the center block in the seventh row, three cracks opened up the entire 

width of the stone, one in the center and the others about 6 inches 

from each end. These cracks were about ¥1¥ inch in width and 

apparently extended entirely through the piece. At 50 minutes a 

thermometer in the center of the wall was replaced, as it seemed that 

the panel would remain in the door.

At 54 minutes the wall bulged to the extent of 2f inches. At 70 

minutes the wall bulged to the extent of 2-^ inches. At 105 minutes
64 FIRE RESISTANCE OF VAEIOUS BUILDING MATERIALS.

no further changes were observed in the condition of the face, and no 

more cracks had developed. The wall at this time had bulged 2finches. It was again feared that the wall would collapse, and a 

picture was taken to show the condition of the cracks on the back. 

At 120 minutes the wall had bulged to the extent of 3 inches.

On removal of the door from the furnace there were only three stones 

that showed signs of spalling. One was in the seventh row, center; 

in another, in the third row on the right, the outer corner had spalled 

off but was. in place; the third instance of spalling was at the upper 

outer corner of the stone in the third row on the left side. The condition of'the surface was about the same as before fire treatment,, 

except that the color had been turned to a brownish blue.

Before the water was applied it was impossible to observe any 

cracks except those mentioned. During the first 3 minutes of the 

water application the stone snapped and cracked audibly, but none 

of the surface fell off. After this the spalling and cracking became 

general, and large pieces varying in depth from 1 inch to 1^ inches 

came off. About one-fourth of the surface of the panel was 

apparently washed away.

Curves showing the variations in temperature observed during the 

test are given in figure 24.

Results. After the water treatment the panel was 2f inches out of 

plumb. The stones on the face were of a reddish-gray color and 

were very badly cracked, and the surface that remained intact could 

be easily crumbled in the fingers. The portions back about 1 inch 

to 1£ inches from the face which had been uncovered were more or 

less hard, but badly split and spalled. The back of the panel was 

also changed in color, but not so much as the face.

On taking down the panel it was found that all the pieces were very 

badly cracked, both across 'the stones and in a plane parallel to the

face. The blocks were as a rule broken into pieces about 4 to 8 inches 

long. The back sides of the stones were found to be badly cracked in 

every direction, and by gentle tapping with the hammer could be 

broken into fragments.

Plate XXVIII, A, shows the face of the panel after firing but 

before quenching. Plate XXVIII, B, shows the face after firing and 

quenching. Plate XXIX, A, shows the condition of the stone on 

being removed from the furnace.

PANEL 24 (Tile).

Material. The material composing panel 24 was 5 by 12 by 12 inch 

partition tile, having three air spaces (fig. 25). The tiles were laid 

as a standard 5-inch partition wall with about |-inch cement-mortar 

joints, having the core holes in a vertical position and broken joints. 

The face and back were plastered with a coat, about $ inch thick, of
U. S. GEOLOGICAL SURVEV 

A. FACE OF PANEL 23, DRESSED GRANITE, AFTER FIRING BUT BEFORE 

QUENCHING.

21. FACE OF 
RESULTS OF TESTS. 65

FIGURE 24. Diagram showing temperature conditions in the furnace and on the back of panel 23. 

Temperature: Maximum, 69°; minimum, 59°; mean, 64°. Relative humidity: 7 a.m., 73; 7 p. m., 74 

Direction of prevailing wind, northwest.

73087 Bull. 370 09 5
66 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

ordinary lime plaster containing a little hair. Over these two coats 

was placed a thin skim of plaster of Paris, put on as a hard finish in 

the usual way.

Test. The tiles were laid up on the afternoon of June 26, 1907, 

plastered the morning of June-27, 1907, and fired July 1, 1907, at 

9.27 a. in. The actual duration of the fire was 2 hours and 1 minute, 

after which the panel was quenched for 5 minutes with water.

In 2 minutes the surface coat of plaster on the fire side fell off, 

coming off in large sheets, about one-third of the panel at a time. At

FIGURE 25. Sketch of partition tile used in panel 24.

6 minutes the furnace was stopped for 5 minutes in order that the 

burners might be cleaned out. This 5-minute intermission was 

deducted from the elapsed time of fire treatment. At 10 minutes 

cracks developed on the back of the panel horizontally across the 

center at the joint on the top of the third row of tiles. At 15 minutes 

steam began to come through the mortar around the edges of the 

panel. At 18 minutes a portion of the lime plaster on the face, about 

2 square feet in area and about 1 foot from the bottom, bulged out 

from the tile about 1 inch. At 33 minutes a crack developed on 

the back of the wall along the bottom of the panel, extending the
U. S. GEOLOGICAL SURVEY BULLETIN 370 PLATE XXIX

A. CONDITION OF DRESSED GRAN.! i£ ON REMOVAL FROM PANEL 23.

11. FACE OF PANEL 24, PARTITION TILE, AFTER FIRING AND QUENCHING.
RESULTS OF TESTS. 67

entire width. The crack across the center of the door, before mentioned, opened to the extent of about fa inch. These cracks could 

not be observed in the plaster on the fired side. At 55 minutes steam 

began coming through the joints around the individual tiles. This 

was more or less general all over the door. At 60 minutes a crack 

developed horizontally at the joint of the fourth and fifth rows of 

tiles and ran entirely across the door. At 95 minutes diagonal cracks 

developed at the upper left-hand side of the panel and ran about 2 

feet out from the corner. At 117 minutes plaster on the right-hand 

side of the door, about halfway up the panel, bulged badly, but did 

not fall off.

Curves showing the variations in temperature observed during the 

test are given in figure 26.

Results. On shutting off the fire and undertaking to slide the 

panel from the furnace the door stuck and permitted the panel to 

come out only about halfway. In endeavoring to pry the door 

entirely open the panel was very badly shaken, and the plaster coating on the fired side, which had been intact up to this time, was 

shaken off. Thirty-seven minutes elapsed from the time the fire 

was shut off until the water was applied, this time being spent in 

trying to remove the door.

On applying the water, only about half of the door, the right-hand 

side, was subjected to the direct impact of the stream, though the 

remaining portion was more or less wet. The severe shaking which 

caused the plaster to fall off probably also cracked many of the 

faces of the tiles which were intact at the time the water was 

applied. By the water treatment the plaster was washed away on 

the lower portion of the back, and badly bulged at the middle height 

over the entire width of the panel.

About 65 per cent of the tiles that were exposed directly to the 

stream were washed away, while those not so exposed were all intact, 

with the exception of two tiles at the bottom; they were, however, 

badly cracked.

After removing the door from the furnace it was found that about 

75 per cent of the faces of the tiles of the entire panel had been washed 

away or would come off by gently tapping with the handle of a light 

screw-driver. The remaining 25 per cent were badly cracked, but 

were apparently rigidly attached to the back part of the tile. The 

faces remaining in place were very badly cracked, and could be easily 

broken in the hand.

On taking down the panel it was found that none of the tiles could 

be taken out intact; they were all cracked across the webs. The 

back portion of the webs and the back faces of the tiles were appar-
68 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

TIME IN MINUTES

FIGURE 26. Diagram showing temperature conditions in the furnace and on the 

perature: Maxiii.um, 83°; minimum, 61°; mean, 72°. Relative humidity: 7 a. in 

tion of prevailing wind, northwest.

back of panel 24. Tem- 

., 91; 7 p. in., 69. Direc-
KESULTS OP TESTS. 69

ently as hard as before the fire treatment. Few cracks were observed 

in this portion.

Plates XXIX, B, and XXX, A, show the face and back of the 

panel after the completion of the test. ... ,

'PANEL 25 (Building Stone).

Material. Panel 25 consisted of five kinds of building stone, viz: 

Bedford limestone from Bedford, Ind.; limestone from Joliet, 111.; 

sandstone from Cleveland, Ohio; marble from Tait, Ga.; and granite 

from the Thousand Islands,, Canada.

The top layers of the panel were filled in with hollow terra-cotta 

tile in order to make the panel as light as possible. There were two 

courses of each kind of stone, laid in cement mortar with broken 

joints.,_ One course of the limestone and one of the sandstone was 

laid on the natural bed; the other had the plane of the natural bed

exposed to the fire. In one course the exposed face of each block 

was 7f inches long and in the other 4£ inches. The panel was backed 

up with common brick to make it less liable to collapse during the 

test.

Test. This test was started at 5.35 p. m. July 1, 1907, and continued for 2 hours. The panel was cooled by a stream of water at 

57 ° F. for 5 minutes. The bulge of the wall was measured on the limestone header which lay flat at the middle height.

In 10 minutes the panel bulged \ inch. At 12 minutes the sandstone block in the left center on the second row spalled to a depth 

of about | inch over the entire face, the piece falling into the pit below. 

At 20 minutes the wall had bulged \ \ inch. The center block in the 

seventh row, composed.' of limestone, spalled, and a piece the entire 

length of the block and about 1 inch in depth fell off. At 24 minutes 

small vertical cracks on the back surface began to develop in nearly 

all the granite blocks. At 30 minutes the wall bulged £ inch, and 

small beads of water were collecting on the back side of the header 

of marble. At 33 minutes small vertical cracks developed in the 

header of Bedford stone. These cracks were about 8 inches apart 

and occurred in all three pieces on the back side of the wall. At 35 

minutes the sandstone blocks in the second row, which had the plane 

of the natural bed parallel to the fired face, were both very badly 

spalled, and the stone on the right side in the second row had crum- 

'bled to a depth of about 3 inches at the end and about 1£ inches at 

the center. At 40 minutes the limestone turned white, having become calcined, and showed fine irregular cracks on the surface. The 

marble also 'showed signs of calcination, the surface becoming white, 

but cracks were not visible. At 50 minutes the wall had bulged -{| 

inch, and at 70 minutes 1£ inches, no apparent change in the surface
70 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

of the stone being noted. At 120 minutes the wall had bulged 1 T3¥ 

inches. After quenching the wall bulged £ inch.

Curves showing the variations in temperature observed during the 

test are given in figure 27.

Results. On removal of the panel it was found that the grariite 

was badly spalled and cracked, but the face was still intact. The 

faces of the limestone were intact but very white, except the piece 

which fell out, before noted. The marble was very badly calcined 

and the face chalky white; no cracks were visible, and the entire face 

was intact. The Bedford limestone was badly cracked and the face 

considerably calcined. The sandstone showed deep seams in the 

pieces that were lying on their natural bed, and the other stones were 

more or less spalled.

During the application of the water the granite, limestone, and 

Bedford stone cracked and their faces washed away considerably. 

The entire surface of the granite was washed away about | inch; 

three of the stones were badly cracked, and the faces fell off to a depth 

of about 2 inches. The limestone was calcined to a depth of about 

1| inches, and most of the faces had fallen off to about this depth. 

The stones were cracked into small fragments (2 to 3 inches) by 

cracks which ran entirely through the pieces. This was true also of 

the Bedford limestone, but the calcining and spalling was only from 

f inch to 1^ inches deep. The marble washed away under the water 

treatment from 1 inch to 1| inches hi depth, and the surface had a 

crystalline and very rough appearance; no cracks were visible in the 

pieces which had the 7f-inch face exposed. The pieces with the 

4 J-inch face exposed were cracked back from the face, the cracks 

being nearly vertical and more or less irregular. The sandstone 

washed away to a depth of about J inch; the surfaces left were hard 

and had turned a dark red. The stones lying on the natural bed 

were not washed away as much as the others, but irregular vertical 

cracks ran all through them, and the seams had opened up. The 

pieces laid with the bedding planes on edge were badly cracked, and 

the water washed them away from \ inch to 1 \ inches in depth. The 

surfaces were rough and of a reddish color and were very badly 

cracked.

On taking down the panel the granite was found to be broken into 

small pieces from 6 to 8 inches in length, the cracks running back 

from the fired face. The limestone came out in small pieces, having 

broken along nearly vertical and horizontal lines. The faces to a 

depth of about 1 inch to 1J inches usually cracked away from the 

back portion. The marble was found to break into pieces about 4 to 

6 inches in length; the cracks, which were not visible before the 

blocks were removed from the panel, were more or less irregular, but 

usually had a general vertical direction. The marble lying with the
U. S. GEOLOGICAL SURVEY 

A. BACK OF PANEL 24, PARTITION TILE, AFTER FIRING AND QUENCHING. . FACE OF 
SESULTS OF TESTS.

900 

800 

700 

600 

500 

-WO 

300 

200 

/OO 

0

/OOO 

^ 900 

^ 800 

i^ 700 

ft 600 

uj 380 

kj 400 

f§ 300 

v 200 

X /OO

^

§

S: /300 Qi

ki /^^

Vs

^ /«%?

9OO

8OO

7OO

GOO

SO

SO

7O

60

SO

30

FACE OF PANEL

lo 9

FURNACE

1,10

\

WATER PYROMETER

^o*

BACK OF PANEL

FIGURE 27. Diagram showing temperature conditions in the furnace and on the back of panel 25. Temperature: Maximum, 83°; minimum, 61"; mean, 72°. Relative humidity: 7 a. in., 91; 7p.m.,G9. Direction of prevailing wind, northwest.
72 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

4|-inch face exposed was cracked in like manner. The Bedford limestone acted like the other limestone, except that the pieces were 

somewhat larger.

The sandstone was badly cracked along the stratification planes 

and also broke into small pieces by cracking perpendicularly to the 

: bed. The blocks lying with the natural bed parallel to the fired face 

cracked more or less irregularly, and their faces were entirely gone.

 Those on the natural bed, however, except for perhaps £ or | inch 

which had washed away, were intact, but split and cracked.

Plates XXX, B, and XXXI, A, show the face of the panel before 

and after testing. Plate XXXI, B, shows the back after testing.

PANEL 26 (Building Stone). '

. Material. Panel 26 consisted of blocks of Georgia marble laid 

with broken joints in cement mortar with 4-inch and 7£-inch faces 

exposed, as shown in Plate XXXII, A. The lower part of the panel 

was backed with common brick, and the upper portion was laid up 

with partition tile in order to make the panel as light as possible.

Test. The test was started at 9.47 a. m. July 6, 1907, and firing 

continued for 2 hours and 1 minute. The panel was cooled by water 

at 61° F. for 5 minutes. A fairly uniform fire was obtained, the top 

being slightly hotter than the bottom and the center of the panel. 

The bulging was measured at the center of the panel on the second 

stretcher of marble.

In 7 minutes cracks developed along the edge of the panel on both

 sides. At 10 minutes the panel had bulged toward the fire about 

| inch. At this time control of the furnace was lost and the temperatures ran too high for three or four minutes. At 75 minutes vertical 

cracks developed on the back of the lower left-hand stone, one about 

3 inches from the edge and one in the center. A vertical crack, starting at the top and running down to the bottom, showed near the 

middle of the center stone of the same row. At 120 minutes the wall 

had bulged -1^-f inches. After quenching the bulging was 1 T9¥ inches.

Curves showing the variations of temperature throughout the test 

are given in figure 28.

Results.- When the door was removed from the-furnace the surface 

appeared to be smooth, but very chalky. On applying water the 

surface slacked for about a minute or two, and gradually washed 

away; then it-became very roughj- showing the crystalline structure 

of the rock, and washed away to a total depth of J inch to If inches. 

After cooling, the surface was found to be very rough and the crystalline structure showed very plainly. Dark streaks in the marble 

withstood, fire and water better and stood out beyond the general 

surface. The narrow faces were apparently more badly damaged, 

being cracked back from the fired face into pieces from 4 to 18 inches
U. S. GEOLOGICAL RURVFY 

A. FACE OF PANEL 25, VARIOUS BUILDING STONES WITH BRICK BACKING, AFTER

TESTING.

11. BACK OF PAN
KESULTS OF TESTS. 73

MOO

900 

800 

700 

600 

SOO 

 WO 

300 

200 

/OO 

0 

1000 

SOO 

800 

700 

600 

SOO

300 

200 

/OO

/300 

/ZOO 

S/00 

/000 

300 

800 

' 700 

600 

S00

400 

70 

60 

SO 

 40

30

4

/

/

/

1,2,3,4,5

;J

1

1

I

7.6.9,10

(

/

/

> *

<S

~/ Z

2

g

*/

17

~7

/

t *~

/2

>4

£ 

/c 

L8 .X^

'9

/

/

,

 '

o

4 

3

f? '4

7

X

_^

6

i

IJ

f/J

[^Hi

^

WAT

,5

 *

:'3 ^

Cf 0

. ?r ®

6

5

?i I

3 $

4

f A>>»/

>8

$*--$!

10

FURNACE

ER Pt

) 

\

\

\

'ROME

15

^T

VfA

i 

T£/7

BACK OF PANEL

^^r*^^

r-^*

.^>(

;5

I

%J& ^y,9

X

^i

i^.

jf

I-" '

8

^7" io 

3

^^^

5

[f 

13

8

7,9 /0\

^

5 5«

| 4j

|

8 «8

^9^5

>- °

K- °

;& T/ME W M/NUTES

FIGURE 28. Diagram showing temperature .conditions in. the furnace and on the back of panel 20. Temperature: Maximum, 79°; minimum, 65°; mean, 72°. Relative humidity; 7a.m., 93; 7 p.m., 86. Direction of prevailing-wind, north. ' >.. " ' 
74 FIRE RESISTANCE OP VARIOUS BUILDING MATERIALS.

in length. The pieces with 7^-inch face exposed showed very few 

visible cracks, but some of them were spalled, with the corners and 

edges washed away. However, on taking the panel down it was found 

that all the pieces of stone were cracked into lengths of about 4 to 6 

inches, the cracks being vertical and running back through the entire 

stone. The 4-inch layers against the sill at the bottom of the panel 

were less affected than any others, but were somewhat protected 

because the brick projected about 1£ inches beyond them.

Plate XXXII, A, shows the face of the panel before firing; Plate 

XXXII, B, shows the face of the panel after firing, but before the 

application of water; Plate XXXIII, A, shows the effect of the water; 

and Plate XXXIII, B, shows the back of the panel after firing and 

quenching.

PANEL 27 (Building Stone).

Material. Panel 27 consisted of blocks of Niagaran magnesian limestone with 4-inch and 7f-inch faces and was built and backed as in 

panel 26.

Test. The test was started at 2.35 p. m. July 8, 1907, and firing 

was continued for 2 hours and 30 seconds: The panel was cooled by 

water at 63° F., applied for 5 minutes. The furnace showed a good 

uniform temperature, slightly hotter at the bottom. The bulging of 

the wall was measured on the second header of limestone at the center. 

This was not quite the center of the panel, but it was deemed advisable to take it there rather than on the brick, which could not be 

rigidly attached to the face.

In 4 minutes the surface of the blocks on the fired side cracked 

until several pieces from the 7f-inch courses fell. At 10 minutes the 

wall had bulged toward the fire T1 <- inch, and at 20 minutes | inch. 

At 27 minutes vertical cracks showed through the center and also 

the lower headers on the back side. These cracks were near the 

middle of the center blocks. Two cracks also developed about equal 

distances from the end in the upper header on the right-hand side. 

At the end of 30 minutes the furnace was shut down for 14 minutes 

in order to clean the burners, into which pieces of the wall had fallen. 

This interval (14 minutes) was deducted from the elapsed time, so 

that the actual firing time was 2 hours. At 40 minutes the panel 

had bulged f inch. The right-hand block in the seventh row cracked 

back to a depth of about 2 inches, and a piece the entire length of the 

block fell off. The left block in the bottom row acted in the same 

manner, a piece about two-thirds of the length of the block and 2 

inches in depth falling out. At 50 minutes the wall bulged \ f inch, 

and at 70 minutes 1 TV inches. At 75 minutes longitudinal cracks 

appeared on the fired face of the left-hand large block of the sixth 

row, also the center block in the third row, and the left-hand block
U. S. GEOLOGICAL SURVEY 

FACE OF PANEL 2u, DRESSED MARBLE, BEFORE HKING. K. FACE OF 
U. S. GEOLOGICAL SURVEY BULLETIN 370 PLATE XXXIII

A. FACE OF PANEL 26, DRESSED MARBLE WITH BRICK. BACKING, AFTER 

FIRING AND QUENCHING.

11. BACK OF PANEL 26, DRESSED MARBLE WITH BRICK BACKING, AFTER 

FIRING AND QUENCHING.
EESULTS OF TESTS. 75

in the second row. The right-hand block in the fifth row spalled all 

over the face, starting from the center and running toward the edges. 

This was also noticed on the right-hand block in the .same row. The 

fire on the right-hand side of the furnace was considerably stronger 

than on the left-hand side, where the burners were clogged by pieces 

of the wall that had spalled off. At 80 minutes the panel had bulged 

1$ inches, and at 120 minutes the bulging amounted to 1J inches. 

After cooling bulging amounted to 1T | inch.

Curves showing the variations of temperature throughout the test 

are given in figure 29.

Results. On removing the panel from the furnace it was found to 

be of a white, chalky color, and all the blocks were more or less cracked 

irregularly. On applying the water the surface was washed away, 

the water being milky white as it came away. The washing 

on the right-hand side of the panel was from J to f inch deep, and

about & inch deep on the left-hand side. The stone snapped and 

cracked under the application of the water, but no pieces flew off. 

A few of the pieces were washed away.

After the door was cooled it was found that on the right-hand side 

of the furnace the blocks were calcined to a depth of about f to 1 inch, 

and were of a whitish color to this depth. The surface was soft and 

chalky, and the blocks were all cracked into small pieces, about 4 to 

6 inches square, most cracks being in the vertical and horizontal 

planes. The faces could be chipped off in irregular layers, but the 

body of each block was cracked into small pieces from 4 to 6 inches 

square. The surface was quite hard, although it flew to pieces when 

tapped with a hammer.

Plate XXXIV, A, shows the face of the panel after firing and quenching; Plate XXXIV, B, shows the back after firing and quenching; 

Plate XXXV, B, shows the appearance of the blocks when removed 

from the panel.

PANEL 28 (Building Stone).

Material. Panel 28 consisted of blocks of Bedford limestone with 

4-inch and 7f-inch faces, and was built and backed as in panels 26 

and 27.

Test. The test was started at 3.02 p. m., July 9, 1907, and firing 

was continued for 2 hours and 45 minutes. The panel was cooled 

by water at 64° F., applied for 5 minutes. The heat in the furnace 

was fairly uniform, being perhaps a little greater on the right-hand 

side.

In 10 minutes the wall bulged toward the fire £ inch at the center, 

the measurement being taken at the second header. No cracking 

was observed up to this time. At 18 minutes the surface began to 

turn a rather chalky.color, but no cracks were noticed, nor was any
76 FIRE RESISTANCE OP VARIOUS BUILDING MATERIALS.

77A55 /A' M/MUTFS

FIGUKE 29. Diagram, showing temperature conditions in the furnace and on the back of panel 27. Tem. 

- perature: Maximum, 85°; minimum,'72°; mean 78V Relative humidity: 7 a.m., 67; 7p.m., 58. Direction of prevailing wind, west.
U. S. GFOI OGICAL SURVEY BULLETIN 370 PLATE XXXIV

A. FACE OF PANEL 27, DRESSED LIMESTONE WITH BRICK BACKING, AFTER 

FIRING AND QUENCHING.

X. BACK OF PANEL 27, DRESSED LIMESTONE WITH BRICK BACKING, AFTER FIRING AND

QUENCHING.
RESULTS OF TESTS. 77

<i

spalling evident. At 20 minutes the wall bulged }f inch. A vertical crack was noticed about 11 inches from the outer edge on the 

back of the right-hand stone of the lower tier. This was not visible 

on the fired side. At 30 minutes the panel had bulged inward about 

1 inch. At 45 minutes the stone in the center row on the right-hand 

side cracked vertically at the center. At 70 minutes the wall bulged 

1£ inches, at 80 minutes l r\ inches, and at 110 minutes 1£ inches, 

but no cracking or spalling was observed up to this time.

Curves showing the variations in temperature throughout the test 

are given in figure 30.

Results. The panel on removal had a white, chalky color, but no 

cracks or indications of spalling were in evidence. On the application of water the color changed to a dark grayish blue, and the surface washed away about \ inch during the treatment.

Cracks developed rapidly in all the pieces during the first 2 minutes, 

but the surface remained intact. During the next 3 minutes pieces 

of various dimensions, from f inch to 1^ inches thick, fell off the 

panel and at the end of the treatment fully 50 per cent of the surface, 

varying in thickness from f to 3 inches, had fallen away. The remaining surface was badly cracked and could be broken off from a depth 

of f inch.to \\ inches by gently tapping. This surface was rough 

and pitted, and also showed considerable calcination. On taking 

down the panel it was found that all the blocks were broken, and 

that they crumbled easily on the fired side, the back being very hard. 

The stones, on removal from the door, fell mostly into pieces from 

4 to 12 inches in length, but some were broken into many little 

cubes <'(2 to 3 inches).

Plate XXXV, A, shows the face of the panel after firing, and Plate 

XXXVI, A, shows its appearance after applying water. Plate 

XXXVI, B, indicates the appearance of the blocks after removal 

from the furnace and gives an idea of the damage wrought.

 . . . ....... PANEL 29 (Sand-Lime Brick).

" Material^- Sand-lime bricks of medium quality were used in 

panel 29. .They were almost white, but had a slightly brownish 

tinge aiid a very few.white lime particles scattered through them. 

The corners and edges were square, the faces smooth, and the bricks 

uniform in :size. The material, however, could be rubbed from the 

faces with the fingers, aiid when two bricks were rubbed together the 

surfaces were abraded considerably. Table 14 gives the physical 

properties and the strength tests of the bricks used.

The panel was composed of. the sand-lime bricks backed with 

common clay brick's and laid in cement mortar as a standard 8-inch 

wall, with headers every sixth row. A small portion of the back 

wall, at the center, was composed of sand-lime bricks.
78 FIEE RESISTANCE OF VARIOUS BUILDING MATERIALS.

800

700

I

FIGURE 30. Diagram showing temperature conditions in the furnace and on the back of panel 28. Temperature: Maximum, 77°; minimum, 69°; mean, 73°. Relative humidity: 7 a. m., 79; 7 p. m., 84. Direction of prevailing wind, east.
U. S. GEOLOGICAL SURVEY BULLETIN 370 PLATE XXXV

A. FACE OF PANEL 28, DRESSED LIMESTONE, AFTER FIRING AND BEFORE 

QUENCHING.

Jl. DRESSED LIMESTONE AFTER REMOVAL FROM PANEL 27.
U. S. GEOLOGICAL SURVE 0 PLATE XXXVI

A. FACE OF PANEL 28, DRESSED LIMESTONE, AFTER FIRING AND 

QUENCHING,

11. BLOCKS OF PANEL 28, DRESSED LIMESTONE, AFTER REMOVAL FROM FURNACE.
RESULTS OF TESTS. 79

Test. The test was made on July 11, 1907, and the firing was continued for 2 hours. The panel was cooled by water at 61° F., applied for 5 minutes and 20 seconds. A fairly uniform furnace temperature, slightly cooler at the bottom at the start, was obtained.

In 10 minutes the wall had bulged at the center about \ inch. 

The bulging was measured at the center of the third header from the 

bottom. At 20 minutes the wall bulged about \ inch, no apparent 

change in the surface being noted up to this time. At 30 minutes 

the wall bulged \\ inch. It was noted that water was forced back 

through one of the bricks in the fourth header near the center of the 

wall. There was a small crack on the surface of the brick, apparently due to shrinkage or improper molding. At 40 minutes the wall 

had bulged to the extent of £ inch. The surface of the bricks on the 

fired side had begun to have a chalky appearance, as if calcination 

of the lime had taken place. At 60 minutes the wall had bulged 

inward to the extent of 1 T3¥ inches, and at 120 minutes l-/f inches. 

After cooling the wall bulged toward the fire \\ inch.

Curves showing the variations of temperature throughout the test 

are given in figure 31.

Results. On removal of the door from the furnace the surface of 

the panel showed no signs of having spalled, but was chalky white 

and looked very soft. On the application of water the surfaces 

washed away from % inch in a few places to about l\ inches in others. 

The surfaces of the majority of the bricks in the panel were washed 

away to the extent of f to f inch.

After the wall had cooled it was found that the surfaces of the 

bricks were very rough and were covered with small irregular cracks 

extending back about 1 inch to 1^ inches. There were also small 

pocklike marks in nearly every brick, apparently where lumps of 

lime had washed away. In one or two places small lumps of sand 

were also found. The remaining portions of the brick on the faces 

were soft and crumbled very easily in the fingers. The back portions 

were nearly as hard as before the fire treatment. When the bricks 

became thoroughly dry, the surfaces were considerably harder. The 

header bricks were found to be cracked and crumbled back to a 

depth of about 1£ inches, the remainder being apparently hard and 

unaffected.

On taking down the panel it was found that the stretcher bricks 

composing the fired side were cracked back vertically from the fired 

face, usually in two or three pieces. The face was taken down with 

great care and about 20 per cent of the bricks were removed intact, 

but nearly all failed in handling, breaking into two or three pieces.

The sand-lime bricks that were laid in the back courses were apparently not affected by the heat and were removed with little loss, but
80 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

FIGURE 31. Diagram showing temperature conditions in the furnace and on the back of panel 29. Temperature: Maximum, 71°; minimum, 03°; mean, 07°. Relative humidity: 7a.m.,87; 7p.m., 86. Direction of prevailing wind, north.
U. S. GFOLOGICAL SURVEY 

\

A. FACE OF PANEL 29, SAND-LIME BRICK, AFTER FIRING AND BEFORE 

QUENCHING.

11. FACE OF P
RESULTS OF TESTS. 81

the mortar stuck to the bricks, and they were hard to clean. There 

was a tendency for the surfaces of the bricks to come away with the 

mortar as it was chipped off.

Plate XXXVII, A, shows the face of the panel after firing; Plate 

XXXVII, B, shows it after the application of water.

PANEL 30 (Tile).

Material.. The material composing panel 30 was 5 by 12 by 12 

inch partition tile, having three air spaces (fig. 25). The tiles were 

laid in cement mortar, with about £-inch joints, as a 5-inch partition. 

They were laid with the core holes vertical and the joints broken. 

The face of the panel was plastered with ordinary lime plaster containing a little plaster of paris and also some hair, the coating being 

about $ inch thick. No hardening coat was put on this panel, as it 

had been found seriously to interfere with the operation of the furnace 

by falling into the burners.

The tiles were sprinkled before laying, as they were so dry that 

they took the moisture from the mortar too rapidly. The tiles were 

laid the morning of July 12; the fired face was plastered the afternoon 

of the same day and the back face the morning of July 13, and the 

panel was shoved into the furnace to protect it from the weather on 

trfe afternoon of the 13th.

Test. The test was started at 10.38 a. m. on July 16, 1907, and 

firing wa,s continued for 2 hours and 30 minutes. The panel was 

cooled for 5 minutes by water at 62° F. A good uniform fire was 

obtained.

As soon as the fire was started the wall began to snap, and small 

pieces of plaster cracked off on the fired side.

At the expiration of 4 minutes the furnace was shut down for 6£ 

minutes, in order to remove plaster that had fallen into the burners. 

About one-third of the plaster had fallen off just prior to this period, 

and during the cleaning of the burners all loose plaster that had 

bulged away from the panel and not fallen off was removed, in order 

to avoid the necessity of shutting down again. At 9 minutes a 

horizontal crack developed on the back between the face and the 

second row of tiles. A similar crack also developed between the 

third and fourth rows. These cracks extended clear across the panel. 

At 10 minutes the wall had bulged inward about J inch, the bulging 

being measured at the center of the fourth row of tiles. At 12 minutes a horizontal crack developed between the second and third rows 

of tiles, extending across the door. At 14 minutes a vertical crack 

developed at the edge along the left side of the panel, starting at the 

top and running down to the joint between the fourth and fifth rows, 

of tiles, and then extending horizontally across the panel.. At 17 

.73087 Bull. 3tO 09 6
82 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

minutes steam began to come through the lower cracks and along the 

sides of the panel, and the moisture began to come through the 

plaster on the back opposite the joints in the tiles. At 19 minutes diagonal cracks from the upper right-hand corner began to show 

through the plaster and to run off across the door. A vertical crack 

developed at the bottom on the left-hand side one tier Out from 

the edge and extended up to the joint between the first and second 

rows, and then ran diagonally across the panel toward the edge. At 

20 minutes the wall had bulged f inch. At 23 minutes all the remaining plaster on the fired side, except a few small areas (3 to 4 

square inches) scattered about the surface, came off, and the furnace 

was shut down for 3 minutes to clean the burners. This time (3 minutes) and that of the previous shut down (6$ minutes) were deducted 

from the elapsed running time of the test. At 30 minutes a series 

of small diagonal cracks. developed at the top of the fourth row of 

tiles on the left-hand side. The cracks were from 3 to 4 inches long 

and about 1 inch apart, and extended from about 6 inches off the 

edge toward the center for a distance of. about 2 feet. At 40 minutes 

the wall had bulged f inch. At 44 minutes the tile on the right-hand 

side of the fourth row cracked horizontally on the fired side, the crack 

occurring about 2 inches from the lower edge and extending 

entirely across the tile. The edges of the crack bulged outward a*nd 

were more or less irregular. At 60 minutes the wall bulged H inch. 

By this time small more or less irregular cracks had developed in 

both vertical and horizontal directions in the plaster on the back 

side of the panel around each tile. At 120 minutes the wall bulged 

f inch. After cooling there was a permanent bulging of £ inch in the 

panel.

Results. -When the panel was removed from the furnace, the plaster 

was practically gone. Around the bottom edge and on the upper 

right-hand and left-hand corners there were small pieces, and a small 

patch on the second and third rows was still intact. The tiles were 

more or less cracked, especially the ones that were entirely free from 

mortar; that is, the second tile from the right-hand side in the third row 

and the tile nearest the right-hand side in the second row; also a small 

corner of the second tile on the right-hand side of the bottom row had 

cracked off. Cracks could not be observed in the other tiles, but they 

had a thin layer of plaster still sticking to them, which prevented 

examination.

On applying water the tiles cracked, and after the first minute the 

faces began to fall off. At the end of 5 minutes about 55 per cent 

of the faces of the tiles was washed away. This occurred on the lower 

and right-hand side of the panel. The tiles on the upper left-hand 

side still were in place. These tiles that were in place, however, were 

found to be cracked loose from the webs near the fired side, and the
U. S. GEOLOGICAL SURVEY

A. FACE L'; : CANEL30, PARTITION TILE, AFTER FIRING AND BEFORE QUENCHING. B, FACE OF PAN
A. FACE OF PANEL 30, PARTITION TILE, AFTER FIRING AND QUENCHING, WITH 

ALL LOOSE PIECES REMOVED.

B. BACK OF PA
KESULTS OF TESTS. 83

faces were all cracked, the cracks running irregularly and a few of 

them exten.ding through the face. A few of the faces of the tiles also 

spalled off to a depth of TV to J inch.

After the wall had cooled it was found that about 55 per cent of the 

tiles that remained in place could be lifted off. Those that did remain 

in place were cracked from the webs, and the faces were cracked but 

were apparently still rigidly attached. The portions of the web 

remaining attached to the backs and the backs themselves were 

apparently hard and free from cracks. The fired faces, however, 

crumbled easily in the hands. The plaster on the back wall was 

forced off, exposing about five tiles at the bottom of the wall; and 

although over the remainder of the wall tho plaster remained intact 

it was badly bulged, and water had come through all the joints.

Curves showing the variations in temperatures throughout the test 

are given in figure 32.

Plate XXXVIII, A, shows the face of the panel after firing and 

before water was applied; Plate XXXVIII, B, the face of the panej 

after quenching; Plate XXXIX, A, the face of the panel after all 

loose pieces had been removed; and Plate XXXIX, B, the back of the 

panel after firing and quenching.
84

/aoo 

//oo 

/ooo

900 

800 

700 

600 

SOO

300 

ZOO 

/OO 

0 

1000

u3

5

6 6.

FACE OF PANEL

10 10*

1

"8

8 8

-20

-8*7

700 

6O8 

SOO 

400 

300 

ZOO 

/OO 

0

FURNACE

900 /r.

WATER PYROMETER

>£_

BACK OF PANEL

T/ME/N M/NUT£S

. Diagram showing temperatureconditions in the furnace and on the back of panel 3(\
RESULTS OF TESTS. 

TABLES.

85

TABLE 1. Panel 1 Results of compression tests made on portions of one-piece doubleair-space mortar building blocks afler fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1. ..................

2............-.----.

3...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

{ 1 

{ \

! 4 

\ 3

Average 

strength.

Exposed 

face.

OOU

898

922

SS5

Unexposed 

face.

1,780

1,754

1,594

1,709

4 parts sand to 1 of Port- 

. land cement.

No. of 

pieces 

crushed.

2

3 

3 

3 

2

Average 

strength.

Exposed 

face.

758 

746

752

Unexposed 

face.

918

1,240

1,263

1,140

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2

2

Average 

strength.

Exposed 

face.

Unoxposed 

face.

584

578

581

MEDIUM BLOCKS.

i. ..................

2...................

3...................

( 4 \ 2 

/ 1 i 2

/ 2

\ 2

ooo

1,457

1,643

1,328

2,337

1,963

2,245

2,182

2

1

2

2 ool

831

1,200

1,533

1,511

1,415

1

i

i

462

462

898

770

645

771

WET BLOCKS.

1. ..................

2...................

3...................

{ i

* i i

{ 2

i yo

1,101 

746

880

1,634

1,940

2,100

1,891

.1

3

2 

4

897

897

2,042

1, 365

1,670

1

1

1

1 

1 

1

540

363 

275

803

950

1,645'

QOO
86 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

TABLE 2. Panel 2 Results of compression tests made on portions of one-piece singleair-space mortar building blocks after fire test.

DAMP BLOCKS. , 

[In pounds per square inch.]

Block No.

1...................

0

3. ...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2 

2 

2 

2 

2 

3

Average 

strength.

Exposed 

face.

1, ooo

1,101

608

1,016

Unexposed 

face.

1,702

1,948

1,299

1,050

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2 

2 

2 

2 

2 

3

Average 

strength.

Exposed 

face.

651

/ J.4

595

653

Unexposed 

face.

535

776

830

714

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2 

2 

3 

2

2

Average 

strength.

Exposed 

face.

531

O4l

344

401

Un- ' 

exposed 

face.

814

548

681

MEDIUM BLOCKS.

1. ..................

2....................

/ 2

I ^ 

I 2 \ 2 

/.....

lj OOO

955

971

1,302

1,758

1,530

2

2 

2

2 

2

1

768

lot

870

812

1,190

933

1,111

1,078

1

1

2

2

2

408

555

482

683

746

713

714

WET BLOCKS.

1. ..................

2...................

3...................

/ 2

1 *

I 2

1 ^ 

/ 2

\ 2

, ^uo

1,876

1,767

1,949

2,808

2,049

2,318

2,391

2

2 

3

2

2

798

684

oOO

779

1,013

1,030

1,222

1 088

2

2 

2

1 

2

657

469

.319

4fi9

645

615

669

fM-J
RESULTS OF TESTS. 87

TABLE 3. Panel 3 Results of compression tests made on portions of one-piece doubleair-space mortar building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1. ........ ..........

3...................

Average......

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

/ 4

i I 

.........

\ 2

Average 

strength.

Exposed 

face.

1,105

Unexposed 

face.

1,833

1-.841

' 1,947

1,874

4 parts sand to 1 of Portland cement.

No. of 

pieces 

.crushed.

 3

2

2 

2

Av.erage 

strength.

Exposed 

face.-

552

552

Unexposed 

face.

949

853

925

909

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2

2

Average 

strength.

Exposed 

face.

493

493

Unexposed 

face.

502

502

MEDIUM BLOCKS.

I...................

2...................

3...................

< 2 1 * 

/ 3

\ 2

/ 2

1 *

1,846

1,105

1,571

1,507

2,570

3,128

2,385

2,694

2

3

3

1, Of *t

yLo

1,155

2,070

2,013

1,712

1,932

2

2

4

404

990

478

827

705

WET BLOCKS.

la..................

2 a. .................

Average

1 2

i 2 

/ 2

\ 3

/ 2

I 2

1,389

2,^550

1,932

1 0^7

2,219

2,5i2

2,699

2,477

2

1 

2

2 

2

2

795

966

992

918

1,C15

1,381

i,487

1,494

........

........

........

a Blocks of 8 parts sand to 1 of Portland cement were destroyed in transit from Underwriters' Laboratories 

to Armour Institute.
88 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

TABLE 4. Panel 4 Results of compression tests made on portions of one-piece singleair-space mortar building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1. ..................

2...................

3...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

/ 2 

i 3

{ 1

i ?

Average 

strength.

Exposed 

 face.

902

1,903

1,462

1,422

Unexposed 

face.

2,219

2,375

1,950

2,181

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

Average 

strength.

Exposed 

face.

'Unexposed 

face.

........ ..........

i

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2

1

3

Average 

strength.

Exposed 

face.

369

596

571

512

Unexposed 

face.

MEDIUM BLOCKS.

1. ..................

2...................

3...................

/ 2

1 9

/ 2

i 2 

I 2

i 1

1,939

2,123

1, 476

1,846

1,795

2,639

2,494

2,309

2

1

2

2

2

1

 979

1,032

1,604

1,205

1,280

1,735

1,436

1,484

1

2

3 

2

3

632

568

650

617

579

722

651

WET BLOCKS.

2«... ...............

3". .................

/ 2

i 1

i 2 \ 2 i 2 \ i

1, 762

1,454

2,312

1,843

2,504

 2,231

2,196

2,310

2

2 

2

1

2

2

1,596

689

1,434

1,240

1,553

1,640

1,361

1,518

........

a Blocks of 8 parts sand to 1 of Portland cemen were destroyed in transit from Underwriters' Laboratories

to Armour Institute.
RESULTS OF TESTS. 89

TABLE 5. Panel 5 Results of compression tests made on portions of one-piece singleair-space mortar building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1... ................

2...................

3...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

{ 1 

{ ! 

{ I

Average 

strength.

Exposed 

face.

1, Ocrx

774

975

1,034

Unexposed 

face.

1,914

1,581

1,825

1,773

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

' 1 

2 

1 

1 

1 

2

Average 

strength.

Exposed 

face.

501

507

466

Unexposed 

face.

906

810

1,246

987

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

1

1

AveraRe 

strength.

Exposed 

face.

408

408

Unexposed 

face.

405

405

MEDIUM BLOCKS.

1.. .................

2...................

3...................

I

o

1

2 

1

1,577

1,406

1,482

1,492

2,152

2,498

2,047

2

1

2 

1

1

709

958

774

1,242

658

628

843

1

4

1

2 

1

1

O£t£t

ooy

665

<M9

1,014

1,005

870

WET BLOCKS.

1. ..................

2...................

3...................

/ 1

i 2

2 

1

1 2

1,786

, lOl

1,780

2,116

2,632

3,066

1,857

2,518

1

2 

1

2 

1

1,652

1,542

2,861

1,459

1,880

2,067

1

3 

1

3 

1

843

0«o

542

671

1,039

781

997

Q<M>
90 FIRE RESISTANCE OF VARIOUS BUILDING MATERIALS.

TABLE 6. Panel 6 Results of compression tests made on portions of one-piece singleair-space mortar building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1. ..................

2...................

3..............'.....

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

/ 3 t 2 

{..... !--- 

Average 

strength.

Exposed 

face.

1, jSOU

1,141

Unexposed 

face.

1,189

1,189

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

3 

2 

2

3 

1

Average 

strength.

Exposed 

face.

740

505

Unexposed 

face.

729

688

571

663

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

1

2

1

Average 

strength.

Exposed 

face.

Unexposed 

face.

- 385

408

265.

353

MEDIUM BLOCKS.

1. ..................

2...................

3...................

3

3

2 1,413

1,550

1,466

1,538

1,502

2

2

2 

2

2

-

J7Ui)

1,081

922

990

1,304

837

1,044

1

2

3

406

515

833

585

WET BLOCKS.

1. ..................

o

3 ...................

Average......

i 2

/ 3

1 * 

1........

2,215

2,215

2,794

2,000

2,397

3

2 

2

2

1,034

1,291

1,163

1,105

1,111

1,108

2

2

2 

2

2

643

718

697

686

827

991

521

780
RESULTS OF TESTS. 91

TABLE 7. Panel 7 Results of compression tests made on portions of one-piece singleair-space mortar building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1. .................. 

2..................

3...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

bO IOt>-* 

Average 

strength.

Exposed 

face.

1,213

1,390

Ot)O

1,153

Unexposed 

face.

1,681

1,432

1,119

1,411

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed, 

i

2 

1 

2 

2

Average 

strength.

Exposed 

face.

485

578

Unexposed 

face.

758

4/1

615

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

2 

2 

2

1

2

Average 

strength.

Exposed 

face.

444

559

502

Unexposed 

face.

493

599

816

636

MEDIUM BLOCKS.

1. ..................

2...................

3...................

/ 2 \ 2 

( 2

1 &

( 2

I 1

1,475

1,366

1,270

1,370

1,603

1,710

1,331

1 *v4£

2'

2 

1

2

2

777

842

1; OUt

974

1,226

987

1,265

1,159

2

2

1

3

730

£.Cl(

509

845

858

927

877

WET BLOCKS.

i. ..................

2...................'

3...................

2

2 

2

2 

2

2

2,161

1,877

2,391

2, 143

2,068

2,490

2,843

...........

2,407

2

2

2 

2

2

1,115

866

802

928

931

1,113

1,086

1,043

2

2

2 

2

2

UU^J

544

467

521

927

963

910

933
92 FIEE RESISTANCE OF VARIOUS BUILDING MATERIALS.

TABLE 8. Panel 8 Results of compression tests made on portions of one-piece singleair-space mortar building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch.]

Block No.

1.. .................

2...................

3...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

{ l 

........

i 2 \ 2

Average 

strength.

Exposed 

face.

1,255

868

1,482

1,202

Unexposed 

face.

978

1,437

1,208

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

1 

2 

1 

3 

1 

2

Average 

strength.

Exposed 

face.

636

1,170

571

792

Unexposed 

face.

834

1,077

612

841

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

1 

1 

1 

2 

1 

1

Average 

strength.

Exposed 

face.

431

263

ZZo

307

Unexposed 

face.

321

545

249

372

MEDIUM BLOCKS.

1.. .................

2...................

3...................

/ 1

\ 2 

/ 2

1 £

1 2

\ 1

2,008

1,784

1, vrto

1,812

3,000

2,302

2,583

.2,628

2

2 

1

2 

1

764

/ to

800

908

1,053

549

837

2

1

2 

1

514

476

495

823

393

724

647

WET BLOCKS.

1...................

2...................

3...................

Average. .....

/ 2

\ 2 / 2

1

i *

1,777

2,159

1,683

1,873

4,046

3,253

2,623

3,307

3 

1

2 

1

1

1,289

909

1,415

1,204

1,805

1,903

2,059

1,922

1

1 

1

2 

1

&

630

503

485

539

923

946

753

874
BESULTS OF TESTS. 93

TABLE 9. Panel 9 Results of compression tests made on portions of two-piece mortar 

building blocks after fire test.

DAMP BLOCKS. 

[In pounds per square inch. ]

Block No.-

1...................

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

i 1

2................... 1 |--2 -

1 * 

3.. ................. ' - -- 

x. .................

Y..................

I 2 

1 

2

Average 

strength.

Exposed 

face.

890

1,007

952

Unexposed 

face.

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

1

L

i

1,219

1,313

1,242

1

1

Average 

strength.

Ex-- 

posed 

face.

350

350

Unexposcd 

face.

059

449

899

GG9

8 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

1

1

4

Average 

strength.

Exposed 

face.

Unexposcd 

face.

300

223

423

315

MEDIUM BLOCKS.

1. ..................

2...................

X................J

Y.... ........... .

1

1

1

2 

1

2

1

1

702

1,423

i,47S

1,201

1,174

1,205

1,200

1,891

1 QIC

1,358

1

2

1

2 

1

' 2

3

1

741

uyo

971

Qno

1,027

535

576

1,133

1,388

<vw

1

3

2

552

552

502

727

015

WET BLOCKS.

i.... ...............

2...................

X..................

Y.... .............

Average. .......

I 1 \ 2

{ '

1

1 9

1

800

\-)6\}£i

1,671

1,244

1,214

750

1,745

1,554

1 dtt

1,345

1

1

2

A , llo

O/l

992

872

1,254

1,461

i ins

1,223

1

1

1

o

531

528

429

530

C23

528
94 FIRE RESISTANCE OP VARIOUS BUILDING MATERIALS.

TABLE 10. Panel 10 Results of compression tests made on portions of two-piece 

mortar building blocks after fire test.

DAMP. BLOCKS. 

[In pounds per square inch.]

Block No.

2...................

 3

X...... ............

Y.... ..............

2 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

! *

I 2

* !

Average 

strength.

Exposed 

face.

543

377

471

464

Unexposed 

face.

920

600

1,034

987

885

4 parts sand to 1 of Portland cement.

No. of 

pieces 

crushed.

Average 

strength.

Exposed 

face.

Unexposed 

face.

8 parts sand to 1 of, Portland cement.

No. of 

pieces 

crushed.

' 2 

1 

2

4

Average 

strength.

Exposed 

face.

473

" '

472

Unexposed 

face.

536

537

537

MEDIUM BLOCKS.

1. ..................

2...................

3...................

X... ...............

Y...... ............

/ 1

\ 2 

/ 1

I 2 

f... .

1 *

804

716

470

663

1,153

845

1,381

1,633

1,253

1

2 

1

1 

1

' 2 

2

3

435

235

348

890

1,231

1,251

1,085

1,192

1,132

1

1

490

321

406

WET BLOCKS.

1. ..................

2...................

3...................

Y..................

Average......

J 1

i 2 

> l

i 2 

] 1

1 9

900

598

788

1,595

1,228

1,686

1,503

1

1

2 

1

2

2

1

435

687

745

622

1,015

1,314

1,493

1,460

1,365

1,329

1

2 

1

1 

1

2

o

523

264

398

661

528

863

823

719
EESULTS OF TESTS. 95 

TABLE 11. Panel 11 Physical properties of brick before firing.

Under normal conditions.

Transverse strength, 

brick not fired.

Breaking 

load.

Pounds. 

1,050 

1,280

Aver...

Modulus 

of 

rupture.

435

528

482

Compressive strength per 

square inch.

Brick 

from 

exposed 

face.

Pounds. 

2,505 

3, 190 

2,498 

3,100 

2,018 

2,452 

3,718 

2,970 

2,290 

2,890 

2,919 

2,055 

3,042

2,793

Brick 

from 

center 

of wall.

Pounds . 

2,420 

2,805 

2,034 

1,990 

2,180 

2,592 

2,922 

2,010 

2,595 

2,810 

2,180 

2,990

Brick 

from 

back 

of wall.

Pounds. 

2,912 

2,048 

2,420 

2,705 

2,940 

2,701 

3,435 

2,580 

2,330 

2,470 

2,430 

2,202

2,510 2,048

Brick 

not 

fired.

Pounds. 

2,711 

2,977 

2,110 

2,903 

2, 400 

3,272 

3,342 

3,239 

2,084 

1,393 

2,870

2,729

Immersed in water 

48 hours.

Compressive 

strength 

per 

square 

inch, 

brick 

not 

fired.

Pounds. 

2,100 

2,100

2,100

Reduction in * 

strength 

in pounds 

per 

square 

inch.

Per cent. 

20.5 

29.0

28.1

Water absorption, brick 

not fired.

30 minutes.

Per ct. 

20.0 

10.5

18.0

4 

hours.

Per ct. 

20.9 

17.2

19.1

48 

hours.

Per ct.

 22.0 

18.3

20.2

TABLE 12. Panel 12 Physical properties of hydraulic-pressed brick before firing.

Normal.

Transverse 

strength, brick 

not fired.

Breaking 

load.

Lbs. 

1,805 

1,790

Aver.

Modulus of 

rupture.

720 

710

718

Compressive 

strength per 

square inch.

Exposed 

face.

Lbs. 

4,007 

2,702 

3,150

3,480 

4,290 

2,590 

3,480 

3,180 

4,110 

4,710 

5,220 

4,000

3,701

Unexposed 

face.

Lbs. 

4,320 

5,830 

3,600

5,560 

3,190 

5,040 

3,420 

4,100 

4,220 

5,720 

3,710 

3,830 

5,040

4,440

Immersed in water 

for 48 hours.

Compressive 

strength per 

square inch.

Exposed 

face.

Lbs. 

2,923 

3,810

Unexposed 

face.

Lbs. 

4,995 

3,881

3,367 4,438

Increase in 

Compressive 

strength.

Exposed 

face.

P.ct.

-9.1

Unexposcd 

face.

P.ct.

Water absorption.

30 minutes.

Exposed 

face.

P.ct. 

9.9 

11.2

Uncxposed 

face.

P.ct. 

10.0 

10.7

-0.1 10.6 10.7

4 hours.

Exposed 

face.

P.ct. 

10.5 

11.2

10.9

Unexposed 

face.

P.ct. 

10. 0 

10.8

10.7

. 48 hours.

Exposed 

face.

P.ct. 

10.5 

11.2

10.9

Unexposed 

face.

P.ct. 

10.0 

10.8

10.7
96 FIEE RESISTANCE OF VARIOUS BUILDING MATERIALS.

TABLE 13. Panel 22 Physical properties of common clay brick before firing. 

[No fired bricks were tested.]

Normal.

Transverse 

strength.

Breaking 

load.

Lbs. 

5,368 

3,442 

3,892 

3,302 

1, 367

Aver.

Modulus of 

rupture.

1,819 

1,167 

1,320 

1,119 

463

1,178

Compressive 

strength per 

square inch.

Exposed 

face.

Lbs.

Unexposed 

face.

Lbs. 

5,563 

2,608

2,762 

3, 466 

4,930

3,866

Immersed in water for 

48 hours.

Compressive 

strength per 

square inch.

Exposed 

face.

Lbs.

Unexposed 

face.

Lbs. 

6,850 

10,230

4,650 

6, 860 

4,867

6,691

Increase in 

Compressive 

strength.

Exposed 

face.

P.ct.

Unexposed 

face.

P. ct. 

23.1

292.0

68.3

98. 0

...... -1.3

96.0

Water absorption.

30 minutes.

Exposed 

face.

P.ct.

TJnexposed 

face.

P.ct. 

8 5

4 hours.

Exposed 

face.

P. ct.

4.7 I......

3.8 '......

4.7 ;......

4.7

Unexposed 

face.

P.ct.

8.5

2.8

5.8

6.0

4.8

5.6

48 hours.

Exposed 

face.

P. ct.

Unexposed 

face.

P.ct.

8.7 

4.6 

6.5 

6.6

4. S

6.2

TABLE 14. Panel 29 Physical properties of sand-lime brick before and after firing.

Not fired. .... 

Average . . 

Brick from back

Average. .

Brick with ends 

exposed ......

Average. .

Brick with face 

exposed ......

Average . .

Normal.

Transverse strength.

Breaking 

load.

Pounds. 

913 

909 

797 

684 

695

800

G42 

841 

770 

789 

645

737

494 

756 

707 

463 

551

594

127 

117 

126

123

Modulus of rupture.

364 

362 

318 

273

277

319

256 

330 

308 

315 

258

295

197 

302 

282 

185 

220

237

58 

53 

58

56

Compressive 

strength 

per 

square 

inch.

Pounds. 

2,020 

2,510 

2,161 

1,923 

1,562

2,035

2,117 

2,109 

1,208 

2,430 

1,790

1,931

1,952 

2,176 

2,109 

1,306 

1,541

1,817

1,112 

1,794 

1,827 

1,994 

2,024

1,750

Immersed in water 

for 48 hours.

Compressive 

strength 

per 

square 

inch.

Pounds. 

1,816 

1,636 

1,604 

1,382 

963

1,480

1,261 

976 

1,451 

1,468 

873

1,206

1,189 

826 

1,157 

1,444 

1,289

1,181

838 

1,384 

902 

1,270 

1,536

1,186

Reduction in 

compressive 

strength.

Per cent. 

10.1 

34.8 

25.8 

28.1 

38.3

27.4

40.5 

53.7 

o20.0 

39.6 

52.2

33.2

39.1 

62.0 

45.0 

a 10. 5 

16 4

30.4

24.7 

22.8 

50.6 

36.3 

24.1

31.7

Water absorption.

30 minutes.

Per cent. 16.33* 

16.30 

9.81 

18.22 

13.04

14.74

15.30 

11.90 

13.72 

13.80 

16.92

14.33

14.65 

12.30 

13.90 

12.00 

10.40

12.65

19.11 

12.70 

18150 

16.60 

12.82

15.95

4 hours.

Per cent. 

16.59 16. 60' 

13.62 

18.29 

13.91

15.80

15.3 

13.45 

15.79 

14.30 

16.92

15.15

14.65 

13.20 

13.90 

13.80 

12.87

13.68

19.30 

13.91 

18.80 

16.60 

13.83

16. 49

48 hours.

Per cent. 

16.59 

16.60 

13.62 

18.29 

14.28

15.88

15.3 

14.00 

15.79 

14.30 

16.92

15.26

14.65 

13.20 

13.90 

13.80 

12.87

13.68

19.30 

14.17 

18.80 

16.91 

14.21

16. 08

Increase.
BIBLIOGRAPHY.

SURVEY PUBLICATIONS ON STRUCTURAL MATERIALS.

The following reports of the Geological Survey relate to structural 

materials, etc. A copy of any except those that are priced can be 

had free by applying to the Director, U. S. Geological Survey, Washington, D. C. The others can be obtained by sending price, in cash, 

to Superintendent of Documents, Government Printing Office, Washington, D. 0.

BULLETIN 243. Cement materials and industry of the United States, by E. C. Eckel.

1905. 395 pp., 15 pis. G5c. 

BULLETIN 260. Contributions to economic geology, 1904. The American cement

industry, by E. C. Eckel, pp. 496-505. 1905. 40c. 

BULLETIN 324. The San Francisco earthquake and fire of April 18, 1906, and their

effects on structures and structural materials, by G. K. Gilbert, Richard L.

Humphrey, J. S. Sewell, and Frank Soule. 1907. 170 pp. 50c. 

BULLETIN 329. Organization, equipment, and operation of the structural materials

testing laboratories at St. Louis, by Richard L. Humphrey. 1908. 85 pp. 

BULLETIN 331. Portland cement mortars and their constituent materials; results

of tests made at the structural materials testing laboratories, St. Louis, Mo.,-

by Richard L. Humphrey and William Jordan, jr. 1908. 130 pp. 

BULLETIN 340. Contributions to economic geology, 1907, part 1. Cement and concrete materials, by E. F. Burchard and G. B. Richardson, pp. 383-416. 1908. 

BULLETIN 344. The strength of concrete beams; result of tests made at the structural

materials testing laboratories, St. Louis Mo., by Richard L. Humphrey. 1908.

58 pp. 

WATER-SUPPLY PAPER 143. Experiments on steel-concrete pipes on a working scale,

by J. H. Quinton. 1905. 61 pp., 4 pis. 5c. 

MINERAL RESOURCES U. S. for 1901 (70c), 1902, 1903 (70c), 1904, 1905 ($1), and

1906 (50c). Contains statistics of production of building stones, cement, and clay.

The volume for 1906 contains Advances in cement technology, by E. 0. Eckel.

pp. 897-905. 

PROFESSIONAL PAPER 11. The clays of the United States east of the Mississippi

River, by H. Ries. 1903.- 298 pp. 40c. 

SIXTEENTH ANNUAL REPORT, pt. 4. Technology of the clay industry, by H. Ries,

pp. 523-575, 4 pis. 1895. $1.20.

FIRE TESTS OF STRUCTURAL MATERIALS.

The following papers contain mention of most of the fire-resistive 

tests of structural materials made since 1890 that have been described in the technical press:

HIMMELWRIGHT, A. L. A. Fireproof construction. Eng. Mag., vol. 12, 1896, pp. 

460-469. Describes seven tests on different types of floors by the New York 

Department of Buildings. 

73087 Bull. 370 09 7 97
98 FIRE RESISTANCE OF VARIOUS. BUILDING MATERIALS.

MCFARLAND, H. B. Tests of the effects of heat on reinforced concrete columns. 

Eng. News, September 20, 1906, pp. 316-318.

McKiBBEN, F. P. Fire and weight test of Columbia fireproof floor. Eng. News, 

November 21, 1904, p. 378. Describes test of floor of reinforced stone concrete 

having veneer of cinder concrete.

SACHS, E. 0. Facts on fire prevention. The result of tests conducted by the British 

Fire Prevention Committee. London, 1902. Vol. 1, 219 pp.; vol. 2, 226 pp. 

Tests of materials, vol. 2, deal chiefly with tests of various types of floors, ceilings, 

and partitions.

WILLEY, D. A. The Underwriters' Laboratories. Sci. Am. Supp., August 22, 1903, 

pp. 23109-23110. Brief description of plant and work.

WOOLSON, IRA H. Tests of the strength and fireproof qualities of sand-lime brick. 

Trials under the requirements of the New York Bureau of Buildings, made at 

Columbia University. Eng. News, June 14, 1906, pp. 662-664.

 Investigation of the effect of heat upon the crushing strength and elastic 

properties of concrete. Eng. News, July 13, 1905, pp. 35-38. Describes laboratory experiments at Columbia University, on trap rock and limestone aggregates. 

Abstract of paper before Am. Soc. Testing Mat.

Investigation of the thermal conductivity of concrete and the effect of heat

upon the strength and elastic properties. Eng. News, June 28, 1906, pp. 723-725. 

Abstract of paper before Am. Soc. Testing Mat. Describes laboratory tests of 

 limestone, trap, cinder, and gravel aggregates at Columbia University.

AMERICAN ARCHITECT. Fireproof construction tests. March 28, 1891. Describes 

tests at Denver, Colo.

ENGINEERING. The results of some tests with fire-resisting material. Nevember 17, 

1905, p. 646. Describes tests and experiments of British Fire Prevention Committee with concrete and reinforced concrete floor arches.

ENGINEERING NEWS. Tests of material for fireproofing columns. September 6, 

1894, p. 184. Gives results of tests at Vienna.

 Tests of fireproof material. September 17, 1896, pp. 182-183. Comparison 

of concrete and hollow tile by New York Department of Buildings.

 Tests of fireproof floor construction. April 22, 1897, pp. 255-256. Describes 

tests of reinforced concrete systems.

 Tests of fireproof partitions by the New York Department of Buildings. December 26, 1901, pp. 482-486. Describes thirteen tests of mortar and plaster 

blocks, concrete blocks, terra cotta, and protected metal strips and metal lath.

 Tests of vulcanite floors. February 8, 1902, p. 116. Describes tests, at Philadelphia, of a steel and concrete construction.

: Fire tests of fireproof floors by the New York Department of Buildings. May 

29, 1902, pp. 441-442. Gives construction of various types tested at Brunswick, 

N.J.,by F. C. VanDyck.

 Tests to determine the fire resistance and heat conductivity of concrete. 

August 3, 1905, pp. 115-116. Abstract of report to National Fire Protection Association on tests of beams made of limestone, gravel, and cinder aggregates.

 Fire tests of reinforced concrete floors. February 1, 1906, p. 115. Describes 

tests at Brunswick, N. J., by F. C. Van Dyck, of reinforced cinder-concrete slab 

and steel I-beam construction and of reinforced stone-concrete slab and girder 

construction.

 - Fire tests of a fireproof floor with bays of different aggregates. February 1, 

1906, p. 116. Gives results for seven aggregates.

Comparative resistance to fire of concrete and cinder concrete. . May 31, 1906,

- p. 603. Tests by British Fire Prevention Committee, of gravel concrete and 

clinker and coke breeze concrete.
BIBLIOGRAPHY. 99

ENGINEERING RECORD. Fireproof construction. April 4, 1891, p. 288. Editorial 

on Denver tests. 

 Tests of fireproof arches at St. Louis. May 7, 1892, pp. 376-377. Describes 

tests of different concrete constructions.

 Fireproof construction. October 7, 1893, p. 14. Mentions various types of 

floors and doors tested at Berlin.

 The best fireproof construction for buildings occupied for mercantile purposes. 

October 9, 1897, pp. 495-498.

 Official test of fireproof floor construction systems. September 18, 1897, pp. 

337-340; September 25, pp. 359-363; October 2, pp. 382-387; October 9, pp. 

403-4.08. Describes tests of fourteen floor systems by the New York Department 

of Buildings in 1896-97. Tests were in kilns over wood fires.

Tests of a new system of terra-cotta floors. February 25, 1905, pp. 220-221.

Describes tests of floor to be used in forty warehouses under construction in Pittsbtirg. Report by Ira H. Woolson.

SCIENTIFIC AMERICAN SUPPLEMENT. The British Fire Prevention Committee and 

its work. June 20, 1903, pp. 22959-22960. Describes testing equipment and 

scope of work.

0