NATIONAL

BUREAU OF STANDARDS

1^
The program of research on building materials and structures carried on by the

National Bureau of Standards was undertaken with the assistance of the Central Housing Committee, an informal organization of governmental agencies concerned with

housing construction and finance, which is cooperating in the investigations through a committee of principal technicians.

CENTRAL HOUSING COMMITTEE

ON RESEARCH, DESIGN, AND CONSTRUCTION

A. C. Shiee, Chairman. Howard P. Vermilta, Vice Chairman.

United States Housing Authority. Federal Housing Administration.

Sterling R. March, Secretary.

Mary F. Taylor, Assistant Secretary.

Pierre Blouke,

Federal Home Loan Bank Board

Hugh L. Dryden,

National Bureau of Standards.

Louis A. Simon,

Public Buildings Administration

Luther M. Leisenring,

Construction Division (War).

Edward A. Poynton,

Office of Indian Affairs.

John S. Donovan,

Farm Security Administration.

George W. Trayer,

Forest Service (F. P. Laboratory).

RoLLO H. Britten,

Public Health Service.

George E. Knox,

Yards and Docks (Navy).

William R. Talbott,

Veterans' Administration.

Wallace Ashby,

Bureau of Agricultural Chemistry and Engineering.

NATIONAL BUREAU OF STANDARDS

STAFF COMMITTEE ON ADMINISTRATION AND COORDINATION

Hugh L. Dryden, Chairman.

Mechanics and Sound.

Phaon H. Bates, Gustav E. F. Lundell,

Clay and Silicate Products, Chemistry.

HoBART C. Dickinson, Addams S. McAllister,

Heat and Power. Codes and Specifications.

Warren E. Emley, Henry S. Rawdon,

Organic and Fibrous Materials. Metallurgy.

The Forest Products Laboratory of the Forest Service is cooperating with both

committees on investigations of wood constructions.

[For list of BMS publications and directions for purchasing, see cover page III.]
UNITED STATES DEPARTMENT OF COMMERCE • Jesse H. Jones, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS73

Indentation Characteristics

of Floor Coverings

by PERCY A. siGLER and myrtle b. woodward

ISSUED APRIL 15, 1941

The National Bureau of Standards is a fact-finding organization;

it does not "approve" any particular material or method of construction. The technical findings in this series of reports are to be construed accordingly.

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • I94I

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE lO CENTS
Foreword

This report supplements Building Materials and Structures

Report BMS14. It contains information on the effect of exposure to accelerated aging and the effect of elevated temperature on the indentation characteristics of floor coverings. The results of indentation

and recovery determinations on a considerable variety of floor coverings are summarized and presented in graphic form to show their

relative comfort value and resistance to permanent indentation under

a concentrated load. Lyman J. Briggs, Director.

[II]
Indentation Characteristics of Floor Coverings

by PERCY A. SIGLER and MYRTLE B. WOODWARD

CONTENTS

Page Page Foreword ii HI. Description of samples 3

I. Introduction 1 IV. Summary of results.- 4

II. Test equipment and procedure 1 V. Comments 7

ABSTRACT

The indentation characteristics of 64 floor coverings were determined. Tests were conducted on specimens

conditioned in an atmosphere of 65-percent relative humidity and 72° F temperature, on specimens after exposure to accelerared aging, and on specimens at an

elevated temperature of 90° F. The floor coverings

tested included such general tj'pes as linoleum, cork, rubber, felt base, asphalt, wood, fiberboard, and monolithic compositions. Variations in composition and

thickness were included in many of the types. The

apparatus and the procedures are briefly described. Summaries of the results are presented to show the

relative merits of the various floor coverings with re- spect to comfort value and permanent indentation.

I. INTRODUCTION

As part of an investigation of the important

properties of floor coverings being conducted

by the National Bureau of Standards, a study was made of theu' indentation characteristics.

This report supplements Building Materials and

Structures Report BMS14, Indentation and

Recovery of Low-Cost Floor Coverings. The

previous report gives the results of indentation

and recovery determinations at various loads

for floor coverings in a comparatively new condition when in an atmosphere of 65-percent

relative humidity at 72° F. The present report

contains information on the effect of exposure

to accelerated aging and the effect of elevated

temperature on the indentation characteristics

of floor coverings. The results of practical

tests to determine the extent to which floor coverings are permanently indented by prolonged exposure to a concentrated load, such as may be imparted by small metal glides on furniture, are also presented in this report.

301765°-41

II. TEST EQUIPMENT AND PROCEDURE

Since the equipment and procedure used in

making the indentation and recovery determinations have been described in detail in re- port BMS14, they are only briefly presented

here. The indentation tester is shown at the right

of figure 1. The tester consists essentially of an indentmg load {A) which can be lowered onto

a plunger {G) equipped with an indenting tool (H). The indenting tool used in these determinations is a flat-ended cylindrical steel rod of

/4-in. diameter. A dial micrometer {G) indi- cates the depth of indentation in a specunen (J).

The specunens were 2 by 2 in. The gage, used to measure the original thick- ness of a specimen (</) as well as the thickness

during recovery, is shown at the left of figure 1. The gage is equipped with a dial micrometer

(ii), graduated in thousandths of an inch, and

a fiat-ended foot (Z) of }8-in. diameter. The

foot exerts a pressure of 20 lb/in. ^ on a specimen.

For testing under normal conditions, speci- mens of the various floor coverings were conditioned in an atmosphere of 65-percent relative

humidity at 72° F for at least 48 hours. The

thickness of each specimen was measured at a marked location in the central portion. The

specimen was then placed under the indenting

tool and the load applied. Time was recoi-ded

from the instant the full load rested on the

specimen. The dial micrometer was read at

intervals for 30 minutes. The load w^as then

removed, and the thiclmess of the indented

portion measured at intervals up to 120 niinules. Indentation and recovery determina-

[I]
tions were made on each floor coverhig for indenting loads of 25 and 100 lb, equivalent to pressures of 509 and 2,038 Ib/in.^, respectively.

The effect of accelerated aging on the indentation characteristics of the floor coverings was

determined by exposing specimens to the heat

and light of a carbon arc of a weatherometer

amperes direct current with an arc voltage of 140 volts. The arc and globe were suspended

at the center of a vertical metal cylinder which

slowly rotated. The specimens were mounted

on the inside of the cylinder facing the arc. The distance of the face of the specimens from

the arc was approximately 14% in. A ther-

- -A

Figure 1.Indentation tester {at right) and thickness gage {at left).

for a period of 28 days. The aged specimens were then conditioned and tested, following the same procedure as that used for testing speci- mens under normal conditions.

The weatherometer was equipped with a

vertical carbon arc surrounded by a clenr globe

of Pyrex glass. The arc was oi:)erated on 13

momcter suspended directly in front of the

specimens showed an average temperature of approximately 138° F. To determine the efl'ect of elevated temperature on the residual indentation characteristics

of the floor coverings, specimens were conditioned in an atmosphere of 65-percent relative

[2]
humidity at 90° V for at least 48 hours. In- dentation and recovery determinations were

tlien made under the same atmospheric contli- tions for an indenting load of 100 lb. Indentation tests of a practical nature were

conducted on many of the floor coverings as an

additional aid in determining their relative

susceptibility to permanent indentation when

exposed to concentrated loads for a prolonged

time. The indenting apparatus consisted of three dome-shaped metal glides of K-in. diameter mounted on one face of a 6- by 6-in. wood

block. The three glides were equally spaced

around the circumference of a circle of 4-in. diameter described about the center of the

block. The procedure followed in testing was

(o place the wood block holding the three metal

glides on the face of a specimen, the thickness

of which had been previously measured at the

locations where the glides contacted the speci- men. The specimens were 6- by 6-in. squares,

or in some cases three 2- by 2-in. squares. A

load of 150 lb was then placed on the block for a period of 7 days. The thickness of the specimen at the indented locations was measured

at 5 minutes and at 7 days after removal of the

load. The average residual indentations in the

various floor coverings at the above periods are recorded in table 1. The tests were conducted

in an atmosphere of 65-percent relative humidity at 72° F.

III. DESCRIPTION OF SAMPLES

The floor coverings tested included such

general types as linoleum, cork, rubber, felt base, asphalt, wood, fiberboard, alumina

cement-latex, magnesium oxycholoride, and

cement mortar. They are listed in table 1. Variations in composition and thickness were

included in many of the types. The generous

cooperation of manufacturers in furnishing

materials is gratefully acknowledged.

Table 1.Floor covcriiu/fi tented and the re.ndiial

iri.dentalions canned by prolonged, exposure (7 dayn) to a concerUrnted load (160 U>. on, 3 metal glides of Yi-in. diameter)

Floor covering Average residual indentation

Type and description '

Battleship linoleum; plain pattern, brown - - . do

-._do Battleship lineoleum; plain pattern, gray

Battleship linoleum; plain pattern, green _ , _ _ _ . _ Marbleized linoleum; marbleized pattern, green Marblei/ed linoleum; marbleized pattern, tan . . _ _ _ Marbleized linoleum; marbleized pattern, white- - _ _

Jaspe linoleum; jaspe pattern, brown _

Inlaid linoli'um; molded pattern, gray

Printed liridli'um; block pattern, brown;

wearing surface, enamel Linoleum tile; marbleized pattern, mahogany___ . Corl<-composition tile; plain pattern, gray , Oork tile; light brown . _

Cork tile; dark brown Rubber tile; marbleized pattern, black

.._.do... __do Rubber tile; mnrbleized iiattern, white Rubber tile: marlilciycd indtern, black Rubber tile; marbleized pattern, gray

Sheet rubber, marbleized puttern, brown.

Felt base; iidaid patlcni, creiim; wearing

surface, linoleum i-oni [Hisitlon Felt base; jiispe pullern, brown; wearing

surface, celluliise nitrate composition,

Felt-base tile; jaspe pattern, brown; wearing surface, cellulose nitrate composition Felt-base tile; jaspe pattern, green; wearing surface, cellulose nitrate composition . _ Felt base; mottled pattern, gray; wearing

surface, resin-treated cotton-linters sheet

Felt base; mottled pattern, white; wearing surface, resin-treated cotton-linters sheet - - . _ _

Felt base; plain pattern, maroon; wearing

surface, asphidt and iiitch compdsil ion Felt base; plain pattern, black; wearing

surface, asphalt and pitcli conipiisiti(in Felt-base tile; plain pattern, red; wearing

surface, asphalt and pitch composition.

Felt base; printed iiattern, lavender; wearing surface, enamel

Felt base; printed pattern, red; wearing

surface, enamel _ _ Asphalt tile; plain imttern, mahogany;

l-miinite iiulenlatioTi, O.IIIO in.b Asphalt tile; plaiii pattern, mahogany;

1-minute indenl:it ion, o.oiig in.b Asphalt tile; pliiin pattern, white; 1- minute indentation, (I. (Ml) in. b _ Asphalt tile; plain pattern, white 1- minute indentation, 0.008 in.i>

Nominal

thick- ness

minutes

after removal

of load

7 days

after removal

of load

Inch

V\ Inch Inch

w

0. 018

.023

0. 00!)

. 0(1!)

.019 . 010 .OW . 007

.013 . 007

>u

. 01

. 014

.011

, 000

. 006

. 006

. 01. 007

'/^ . 01 . 006 M

>U

MsH

MrH

M«

.012

.083

. OO.'i .007

.007

.006

, 003

, 041

. 048

. 003

. 003

. 002 MrH

H

.OOfi

.OOfi .003

.003

¥,< . 01.') .012

•H.t .022 . 018

%i .02,'i .022

Vm .033 .026

Me . 017 . 013

%4 .020 .014 %2 .021 .01!)

.023 .022 Me .01.5 .011 %i .021 .018

•He .016 .012 H .011 .008 Me .024 . 020 H .014 . 01

See lootnoto at end of table.

[3]
Table 1.

Floor coverings tested and the residual indentations caused hy -prolonged exposure {7 days)

to a concentrated load {150 lb on 3 metal glides of

Yi-in. diameter) —Continued

Floor covering

Type and description

Asphalt tile; plain pattern, green; 1- minute indentation, 0.012 in.b Asphalt tile; plain pattern, green; 1- minute indentation, 0.010 in.b Asphalt tile; plain pattern, red; 1-minute

indentation, 0.010 in.t Asphalt tile; plain pattern, red; l-minute

indentation, 0.007 in.i> Asphalt tile; plain pattern, black; 1- minute indentation, 0.010 in.'> Asphalt tile; raarbleized pattern, white; 1-minute indentation, 0.006 in.b Asphalt tile; plain pattern, maroon; 1- minute indentation, 0.011 in.b_ Strip Douglas fir; edge-grained; densitj', 271h/ft3e _. Strip Douglas fir; edge-srained; density,

36 lb/ft 3 c Strip vellow pine; flat-grnined; density,

441b7ft 3 c Strip white oak; flat-grained; density,

40 lb/ft 3 c Short-strip maple; flat-grained; density, 47Ib/ft3 c White-oak unit-block; flat-grained Red-oak unit-block; flat-grained Douglas-fir plywood; 5-ply Rock-elm plywood tile; 3-ply Rock-elm plywood tile; 3-ply Rock -elm plywood tile; 3-ply _ Pressed flberboard tile; density, 67

lb/ft 3 c Asphalt-impregnated flberboard tile; dull black Asphalt-impregnated flberboard tile; green Alumina cement-latex composition; aggregate, marble chips and volcanic ash; density, 120 lb/ft 3 c Alumina cement-latex composition; ag- gregate, ground cork and silica; density,

61 lb/ft 3 c Magnesium-oxychloride composition; ag- gregate, marble dust, cotton fiber, and

copper powder; density, 108 lb/ft ' " Magnesium-oxychloride composition; ag- gregate, calcite; density, 108 lb/ft ' c Magnesium-oxychloride composition; aggregate, granite dust; density, 118 lb/

ft 3 c 1:2 cement-mortar topping; aggregate, Potomac-River sand; density, 137

ib/rt 3 c

Nominal

thick- ness

Inch Me

2^2

Average residual indentation

5 minutes

after removal

of load

Inch

.070

.053

.021

.019

.016

.010

.015

.010

.006

.008

.005

.00?

.003 .004

.011 .005 .008

.006

.001

.058

.063

.015

.043

7 days

after removal

of load

.000

.000

Inch

. 068

. 053

.021

. 015

,ni4

009

. 012

. 007

.003

. 005

.003

.001

. 002

.003

.008 .003

.005

.003

.000

.044

.045

a f'nldi livtcil is the nredominatinsi color.

b Mrili, [ |.M rrihed" in FedenM Specification SS-T-306, Tile; Asphalt,

o At (l.'i-|ic ii i'nl relative humidity and 72° F.

IV. SUMMARY OF RESirLTS

The results of the indciitiilion aixi recovery

dctermiiialioiis on the 64 floor coverings are summarized and shown graphically in figures

2 to 13, inclusive. The values reported repre- sent the average of separate determinations on

at least three specimens. The quantity C is the initial indentation (30 seconds after application of the load) in mils for a load of 25 lb on the /4-in. flat-ended indenting tool, and is used as an approximate measure of the relative

comfort value of the floor coverings with respect

to the physical fatigue of occupants. The

quantity / is the residual indentation in mils

120 minutes after the removal of a load of 100

lb which has been applied for 30 minutes, and

is used to show the relative extent to which the

floor coverings are permanently indented by a severe load. The unshaded blocks show the

S 6 7 NUMBER Figure 2.

Sheet linoleums.

C, initial indentation in mils for load of 25 lb. (An api)roxiniate measure of the relative comfort value)

0 NORMAL

[high temp.

I AGED

i 4 -5 6 SAMPLE NUMBER Figure 3.

Sheet linoleums.

I. residual indentation in mils 120 minutes after removal of load of 100 lb. (The extent to which the surface is permanently indented by a

severe load) indentation characteristics of floor coverings in a comparatively new condition when in an

atmosphere of 65-percent relative humidity at 72° F. The single-shaded blocks show the

results of similar tests on specimens exposed to accelerated aging. The double-shaded blocks

show the residual indentations obtained on

specimens at a temperature of 90° F.

[4]
13 li IS 16 n 18 19 SAMPLE NUMBER Figure 4.

Linoleum tile, cork composition tile, cork

tiles, rubber tiles, arid sheet rubber.

C, initial indention in mils for load of 26 lb. (An approximate measure of the relative comfort value)

Figure 7.

Felt-base floor coverings.

I, residual indentation in nuls 120 minutes after removal of load of 100

lb. (The e.xtent to which the surface is permanently indented by a severe load)

Figure 5.Linoleum tile, cork composition tile, cork

tiles, rubber tiles, and sheet rubbers.

I. residual indentation in mils 120 minutes after removal of load of 100

lb. (The e.xtent to which the surface is permanently indented by a severe load)

/4

I/O

?

uj B Q

5 6 <t 4 5 ^

0

normal

i AGED

^4 2S Z6 Z7 eS Z9 30 3/ SAMPLE NUMBER Figure 6.

Felt-basc floor coverings.

C, initial indentation in mils for load of 25 lb. (An approximate measure of the relative comfort value)

2 0

normal

1 AGED

3S 36 37 3 SAMPLE

1 rfa

) 33 40 4/ NUMBER

42 43

Figure 8.Asphalt tiles.

C, initial indentation in mils for load of 25 lb. measure of the relative comfort value) (An approximate

NORMAL

jHIGH TEMP

! AGED

zo

_i

<g IZ o

- 10

36 37 38 ' 33 40 SAMPLE NUMBER Figure 9.

Asphalt tiles.

I, residual indentation in rails 120 minutes after removal of load of 100

lb. (The extent to which the surface is permanently indented by a severe load)

[5]
In gonei-al, the effect of accelerated aging on

the indentation characteristics of the floor coverings was a decrease in the depth of indentation under load as well as a decrease in the

residual indentation after removal of a load.

In view of the small decrease in the C value, even though an objectionable trend, in comparison to the decrease in the / value, which is a desirable trend, it would appear that accel- erated-aging tests are not necessary for deter-

'4J '^J 47 '48 43 SO sT sJ sl s4 SAMPLE NUMBER FiouRE 10.

Woods.

C, initial indentation in mils for load of 25 lb. (An appro.ximate measure of the relative comfort value)

<n IS

g

I-Q

<

cn

UJ

<^ 6

normal

Ihigh temp

i AGED

4(5 4 7 48 45 so si SAMPLE NUMBER Figure 1 I

. — Woods.

I. residual indentation in mils 120 minutes after removal of load of 100

lb. (The e.xtent to which the surface is permanently indented by a severe loud)

mining- the indentation properties of floor coverings.

High temperature increases the residual

indentation, or / value, in many of the floor coverings. In some the increase is small. In

others it is appreciable and warrants consideration. Of the general types, those in which

asphalt is used as an ingredient are the more

noticeably and consistently aft'ected. The relative resistance of the floor coverings

to permament indentation as determined by

tests of a practical nature and shown in table 1, is in good agreement with the relative resistance

as shown by the / values under normal conditions presented in the figures, with the exception

of the asphalt tiles, samples 34 to 44 inclusive,

56 53 60 ei 61 63 64 SAMPLE NUMBER Figure 12.

Fiberboards and monolithic compositions.

C, initial indentation in mils for load of 25 lb. (An appro.\iniate measure of the relative comfort value)

io\-

/a

cn

<g 12- Q

- fo <9 8

a: 6

4

2

-

Z6I „m 313 89 J3 63 38 2/ m in

normal

jHIGH TEMP

I AGED

61 NUMBER

64

Figure 13. —Fiberboards and monolithic compositions.

I, residual indentation in rails 120 minutes after removal of load of 100

lb. (The extent to which the surface is permanently indented by a severe load)

and the alumina cement-like composition containing an aggregate of ground cork, sample 60. The relatively higher permanent indentations

for asphalt tile, shown in table 1, are due to the

characteristic of asphalt tiles in general to have

a prolonged time-rate of indentation.'

1 J. W. McBurnev, Indentation of Asphalt Tile, Proc. Am. Soc. Testing

Materials U, pt. 2591 (1934).

[61
The rolativoly highoi' / value for sample fiO, shown in figure i:^, is due to the erushing of the

material at the higher pressure.

V. COMMENTS

The ideal floor covering for comfort and

resistance to indentation is one which possesses

a high C value and a low / value. Unfortunately, these two properties oppose each other

in most floor coverings, and it is necessary to

select a compromise between the two. Figure

14 represents a composite and convenient comparison of the indentation characteristics of the floor coverings under normal conditions.

o

o

IO liJ T >

1 14,15,60

3.6 2,4 57,58

5,7,8,9,

11,12,20,22 27 24,25,28,30, 32,33

26,31

18 10,13,16,17, 19,21,40 23,3839,54 5259 29

34,35,37,43, 44,46,48/V9,

50,51,53,56, 61,62,63,64

36,41,42,47, 55 45

VERY GOOD LOW

GOOD FAIR

I - VALUE POOR VERY POOR > HIGH Figure 14.

Composite comparison of the indentation

characteristics of floor coverings under normal conditions.

C-value, their ability to yield under foot, /-value, their re.«istance to perraament indentation under a concentrated

load.

The numbers in the chart correspond to the

sample numbers in table 1. It can be seen that

most of the linoleums and the softer types of rubber floor coverings possess a fair to good

combination of the C and / values. Exceptions

in the linoleums were the K-in. battleship

linoleum, sample 1, which had a high / value.

and the %4-in. inlaid liiiolciiiu, samjjlc 10, which

had a low (J value.

if resistance to severe loads or abusive treat- ment is essential, a floor covering with a very

low / value would be the least damaged or marred in such service. The oak and maple

wood floors, pressed fiberboard, magnesium

oxychloride floors, and the cement-mortar

topphig had a very low I value. Some of the

asphalt tiles had a low / value under normal

conditions. However, their / value was appreciably increased at an elevated temperature or by prolonged exposure to a concentrated load

(see fig. 9 and table 1). The cork tiles, samples 14 and 15, and the

alumina cement-latex floor with an aggregate

of ground cork, sample 60, were outstanding as regards a high comfort value. These floors,

however, would require exceptional precautions

against concentrated loads. The indentation characteristics of the felt- base floor coverings, samples 23 to 33, inclusive,

as a whole were not desirable. Although they

had a fair comfort value, their residual indentations were high. It should not be concluded,

however, that this group of floor coverings

should not be considered. Their niitial cost is comparatively low, and they may render eco- nomical and satisfactory service for some types

of occupancy, provided they are amply protected from concentrated loads.

It should be noted that this report deals only

with the indentation characteristics of floor coverings without consideration of other properties, such as resistance to abrasion, resistance

to tear and fracture, dimensional changes

with change in atmospheric conditions, and

resistance to cleansing and finishing materials.

Additional information on floor coverings is given in Building Materials and Structures

Reports 14, 34, 43, 59, and 68 (see cover pages

III and IV).

Washington, Februarv 7, 1941.

o

[7]

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BMSl Research on Building Materials and Structures for Use in Low-Cost Housing 10^ BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 10^ BMS4 Accelerated Aging of Fiber Building Boards 100 BMS5 Structural Properties of Six Masonry Wall Constructions 150 BMS6 Survey of Roofing Materials in the Southeastern States 150 BMS7 Water Permeability of Masonry Walls 100 BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 100 BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs 100 BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 100 BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 100 BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 150 BMS13 Properties of Some Fiber Building Boards of Current Manufacture 100 BMS14 Indentation and Recovery of Low-Cost Floor Coverings 100 BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored by

Wheeling Corrugating Co 100 BMS16 Structural Properties of a "Tilecrete" Floor Construction Sponsored by Tilecrete Floors, Inc 100 BMS17 Sound Insulation of Wall and Floor Constructions 100 BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation 100 BMS19 Preparation and Revision of Building Codes 150 BMS20 Structural Properties of "Twachtman" Constructions for Walls and Floors Sponsored by

Connecticut Pre-Cast Buildings Corporation 100 BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association 100 BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 100 BMS23 Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick

Manufacturers Association of New York, Inc 100 BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile CavityWall Construction Sponsored by the Structural Clay Products Institute 100 BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions,

Floors, and Roofs 150 BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction

Sponsored by the Nelson Cement Stone Co., Inc 100 BMS27 Structural Properties of "Bender Steel Home" Wall Construction Sponsored by The

Bender Body Co 100 BMS28 Backflow Prevention in Over-Rim Water Supplies 100 BMS29 Survey of Roofing Materials in the Northeastern States 100 BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas

Fir Plywood Association 100 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co 150 BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block WaU Construction Sponsored by the National Concrete Masonry Association. 100

[List continued on cover page iv]
BUILDING MATERIALS AND STRUCTURES REPORTS

[Continued from cover page III] BMS33 Plastic Calking Materials lOji BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 lOjS BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging lOjS BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions

With "Red Stripe" Lath Sponsored by The Weston Paper and Manufacturing Co— 10^ BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors, Sponsored by Palisade Homes 10^ BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co 10^ BMS39 Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co lOfi BMS40 Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored

by Knap America, Inc 10(S BMS41 Effect of Heating and Cooling on the Permeability of Masonry Walls 10^ BMS42 Structural Properties of Wood-Frame Wall and Partition Constructions With "Celotex"

Insulating Boards Sponsored by The Celotex Corporation 10(4 BMS43 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 10^ BMS44 Surface Treatment of Steel Prior to Painting 10(4 BMS45 Air Infiltration Through Windows 10^ BMS46 Structural Properties of "Scot-Bilt" Prefabricated Sheet-Steel Constructions for Walls,

Floors, and Roofs Sponsored by The Globe-Wernicke Co 10(4 BMS47 Structural Properties of Prefabricated Wood-Frame Constructions for Walls, Partitions,

and Floors Sponsored by American Houses, Inc 10(4 BMS48 Structural Properties of "Precision-Built" Frame Wall and Partition Constructions

Sponsored by the Homasote Co 10(4 BMS49 Metallic Roofing for Low-Cost House Construction 10^ BMS50 Stability of Fiber Building Boards as Determined by Accelerated Aging 10^ BMS51 Structural Properties of "Tilecrete Type A" Floor Construction Sponsored by the Tile- crete Corporation 10^ BMS52 Effect of Ceiling Insulation on Summer Comfort 10^ BMS53 Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored by the Munlock Engineering Co 10(4 BMS54 Effect of Soot on the Rating of an Oil-Fired Heating Boiler 10^ BMS55 Effects of Wetting and Drying on the Permeability of Masonry Walls 10(4 BMS56 A Survey of Humidities in Residences 10^ BMS57 Roofing in the United States; Results of a Questionnaire 10(4 BMS58 Strength of Soft-Soldered Joints in Copper Tubing 10^4 BMS59 Properties of Adhesives for Floor Coverings 10^ BMS60 Strength, Absorption, and Resistance to Laboratory' Freezing and Thawing of Building

Bricks Produced in the United States 15j4 BMS61 Structural Properties of Two Nonreinforced Monolithic Concrete Wall Constructions 10(4 BMS62 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by the Portland Cement Association 10(4 BMS63 Moisture Condensation in Building Walls 10(4 BMS64 Solar Heating of Various Surfaces 10^ BMS65 Methods of Estimating Loads in Plumbing Svstems 10^ BMS66 Plumbing Manual 1 20^ BMS67 Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by Herman A. Mugler 15^4 BMS68 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 3 15^ BMS69 Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 10^ BMS70 Asphalt-Prepared Roll Roofings and Shingles 15<4 BMS72 Structural Properties of "Precision-Built, Jr." Prefabricated Wood-Frame Wall Construction Sponsored by the Homasote Co 10^ BMS73 Indentation Characteristics of Floor Coverings lOji