^ietorer?cc ?)nG!' not to

laKeii iroiii liie Library.

U. S. DEPARTMENT OF COMMERCE
BUILDING MATERIALS AND STRUCTURES REPORTS

On request, the Superintendent of Documents, U. S. Government Printing Office, Washington)

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The following publications in this series are available by purchase from the Superintendent of Documents at the prices indicated:

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.- 10^5 BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 10^ BMS4 Accelerated Aging of Fiber Building Boards 10^ BMS5 Structural Properties of Six Masonry Wall Constructions 15(4 BMS6 Survey of Roofing Materials in the Southeastern States 15^ BMS7 Water Permeability of Masonry Walls 10^ BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10^ BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs 10(4 BMSlO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 10(4 BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions lOjS BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 15^ BMS13 Properties of Some Fiber Building Boards of Current Manufacture 10(5 BMS14 Indentation and Recovery of Low-Cost Floor Coverings 100 BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored by

the Wheeling Corrugating Co 100 BMS16 Structural Properties of a "TUecrete" Floor Construction Sponsored by Tilecrete Floors, Inc lOfS BMS17 Sound Insulation of Wall and Floor Constructions 100 Supplement to BMS 17, Sound Insulation of Wall and Floor Constructions 50 BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation 100 BMSIO 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 WaU 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" WaU Construction

Sponsored by the Nelson Cement Stone Co., Inc 100 BMS27 Structural Properties of "Bender Steel Home" WaU Construction Sponsored by the Bender Body Co 100 BMS28 Backfiow Prevention in Over-Rim Water Supplies 100 BMS29 Survey of Roofing Materials in the Northeastern States 100 BMS30 Structural Properties of a Wood-Frame WaU Construction Sponsored by the Douglas

Fir Plywood Association 100 BMS31 Structural Properties of "Insulite" WaU and "Insulite" Partition Constructions Sponsored by The Insulite Co 150

[List continued on cover page iii]
UNITED STATES

NATIONAL

DEPARTMENT OF C O M M E K E • Jesse H. Jones, Secretary

BUREAU OF STANDARDS • Lyman J. Briggs, Director BUILDING MATERIALS

and STRUCTURES

REPORT BMS99

Structural and Heat-Transfer Properties of "Multiple Box-Girder

Plywood Panels" for Walls, Floors, and Roots

Sponsored by Loren H. Wittner

hy HERBERT L. WHITTEMORE, VINCENT B. PHELAN, and RICHARD S. DILL

with the collaboration oj

R. F. LUXFORD

Forest Products Laboratory

Forest Service, United States Department of Agriculture

ISSUED JUNE 11, 1943

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

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

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON - 1943

FOR SALE BY THE SU I' ERIN TEN DENT OF DOCUMENTS, U. S. GOVERNMENT PRINTING OFFICE

WASHINGTON, D. C. • PRICE 15 CENTS
Foreword

This report is one of a series issued by the National Bureau of Standards on the

structural and heat-transfer properties of constructions intended for low-cost houses

and apartments. The constructions described herein were sponsored by Loren H. Wittner, a builder, and were included in the program for the determination of the structural

properties at the request of the War Department due to its search for improved house

constructions suitable for war requirements.

The sponsor built and submitted the specimens described in this report for participation in the program outlined in BMS2, Method of Determinmg the Structural Properties

of Low-Cost House Constructions. The sponsor, therefore, is responsible for the design

of the constructions and for the description of materials and method of fabrication. The

Bureau is responsible for the testmg of the specimens and the preparation of the report.

This report covers the load-deformation relations and strength of the elements when

subjected to compressive, transverse, concentrated, impact, and racking loads by standardized methods simulating the loads to which the elements would be subjected in actual

service. Heat-transfer coefficients determined by tests in a shielded hot-box heat-transfer apparatus also are included.

The National Bureau of Standards does not "approve" a construction, nor does it express an opinion as to its merits for reasons given in reports BMSl and BMS2. The

technical facts presented in this series provide the basic data from which architects and

engineers can determine whether a construction meets desired performance requirements.

Lyman J. Briggs, Director,

[n]
Structural and Heat-Transfer Properties of "Multiple BoxGirder Plywood Panels" for Walls, Floors, and

Roofs Sponsored by Loren H. Wittner

by HERBERT L. WHITTEMORE, VINCENT B. PHELAN, and RICHARD S. DILL

with the collaboration of

R. F. LUXFORD

Forest Products Laboratory, Forest Service, United States Department of Agriculture

CON

Page

Foreword ii

I. Introduction 2

II. Sponsor and product 2

III. Specimens and tests 2

1. Structural 2

2. Heat transfer 5 IV. Materials 5

1. Wood 5

(a) Framing 5

(b) Plywood, moisture - resistant type 5

(c) Plywood, exterior type 6

2. Fastenings 7

(a) Nails 7

(b) Corrugated fasteners 7

3. Glue 7 V. Structural properties 7

1. Wall T>R 6

(a) Sponsor's statement 7

(1) Four-foot wall speci- mens 7

(2) Eight-foot wall speci- mens 8

(b) Compressive load 9

(c) Transverse load 10

(d) Concentrated load 11

(e) Impact load 12

ENTS

Page

V. Structural Properties—Continued.

1. Wall Continued.

(f) Racking load 12

2. Floor DS, 13

(a) Sponsor's statement 13

(1) Description of speci- mens 13

(b) Transverse load 14

(c) Concentrated load 15

(d) Impact load 15

3. Roof DT 17

(a) Sponsor's statement 17

(1) Description of speci- mens 17

(b) Transverse load 17

(c) Concentrated load 18

4. Roof DV 18

(a) Sponsor's statement 18

(1) Description of speci- mens 20

(b) Transverse load 20

(c) Concentrated load 21

VI. Heat-transfer properties 21

1. Walls HT60, HT61, and HT62 21

(a) Description of specimens 21

(b) Test results 22

VII. Additional comments by sponsor 24

ABSTRACT

To determine structural and heat-transfer properties,

tests were conducted at the request of the War Department on wall, floor, and roof specimens of "Multiple

Box-Girder Plywood Panels." The specimens were

constructed by gluing and nailing one sheet of plywood

between two frames and facing the outer surfaces with

other sheets of plywood. The longitudinal and trans- verse members of the frames with the sheets of plj'wood

formed closed cells, which provided heat insulation. The wall specimens were subjected to compressive.

transverse, concentrated, impact, and racking loads; the floor specimens to transverse, concentrated, and

impact loads; and the roof specimens to transverse and concentrated loads. The loads simulated the loads

to which the elements are subjected in actual service. The deformations under load and the sets after the load was removed were measured for uniform incre- ments of load. The results are presented in graphs

and tables. The heat-transfer properties of three wall specimens were determined in a shielded hot-box heat-transfer apparatus.

[1]
I. INTRODUCTION

To provide technical facts on the performance

of constructions for low-cost houses, to discover

promising new constructions, and ultimately to determine the properties necessary for acceptable

fx'rformance in actual service, the National

Bureau of Standards invited the cooperation of the building industry in a program of research on building materials and structures suitable

for low-cost houses and apartments. The

objectives of this program are described in

BMSl, Research on Building Materials and

Structures for Use in Low-Cost Housing.

To determine the strength of house constructions in the laboratory, standardized methods

were developed for applying loads to portions of a completed house. Included in this study were masonry and wood constructions of types that

have been extensively used in this country for houses and whose behavior under widely

different service conditions is well known to builders and to the public. The reports on

these constructions are BMS5, Structural Properties of Six Masonry Wall Constructions, and

BMS25, Structural Properties of Conventional

Wood-Frame Constructions for Walls, Partitions, Floors, and Roofs. The masonry speci- mens were built by the Masonry Construction

Section of this Bureau, and the wood- frame

specimens were built and tested by the Forest

Products Laboratory at Madison, Wis.

The present report gives the structural properties of w^all, floor, and roof constructions.

The wall specimens wore subjected to compressive, transverse, concentrated, impact, and

racking loads simulating the loads to which the

walls of a house are subjected. In actual service, compressive loads on a wall are produced

by the weight of the roof, second floor and

second-story walls, if any, by furniture and oc- cupants, and by snow and wind loads on the

roof. Transverse loads on a wall are produced

by wind, concentrated and impact loads by ac- cidental contact with heavy objects, and racking loads by the action of wind on adjoining

walls. Transverse loads are applied to floors by furniture and occupants ; concentrated loads

by furniture, for example, the legs of a piano;

and impact loads by objects falling to the floor. Transverse loads are applied to roofs by wind

and snow; concentrated loads by persons walking on the roof, and by tools and equipment

when the roof is constructed or repaired.

The deflection and set under each increment

of load were measured, because the suitability

of a construction depends not only on its resist- ance to deformation when loads are applied

but also on its ability to return to its original

size and shape when the loads are removed.

The heat-transfer properties of three wall

specimens were determined in a shielded hotbox heat- transfer apparatus. To simulate conditions which might exist in actual service, the

temperature of the air near the outside face was

maintained at 0° F and that near the inside

face at 70° F. The observed thermal transmittaiice also was corrected for a wind velocity of 15 mpli on the outside face of the wall and zero

velocity on the inside face.

II. SPONSOR AND PRODUCT

Wall, floor, and roof specimens of Multiple

Box-Girder Plywood Panels are covered by

U. S. Patexat 2,295,248, September 8, 1942, is- sued to Loren H. Wittner and licensed without

royalty to the United States Government.

In these specimens three sheets of Douglas

fir plywood were glued and nailed to two wood

frames; one sheet of plywood was fastened between the frames and the other two to the outer

surfaces. The longitudinal and transverse members of the frames formed closed cells between the

plywood

.

III. SPECIMENS AND TESTS

1. Structural

The specimens represented three elements of a house and were assigned the following symbols: wall, DR; floor, DS; roof, DT; roof, demountable type, DU. The individual speci- mens were assigned the designations given in table 1. Except as mentioned below, the specimens were tested in accordance with BMS2. That

report also gives the requirements for the

specimens and describes the presentation of the results, particularly the load-deformation

graphs. The wall specimens were symmetrical

[2]
with respect to a plane at midtliickness.

Consequently the transverse, concentrated, and

impact loads were applied to one face only.

Because under compressive load the shortening of the entire specimen may not be

proportional to the values obtained from

compressometers attached to the specimen over

only a portion of its height, the shortenings

and the sets were measured with compressometers attached to the steel plates through

which the load was applied, not to the specimen, as described in BMS2.

Table 1.Spechnen designations

Element

WalL Do

Do. Do

Do.

Floor Do. Do.

Roof- Do.

Do. Do

Construction symbol

DP

DR. DP.

DR.

DB.^

DS.

DS.

DS. DT. DT. DU

DU

Specimen

designation

C/, C«, C3 . . ri, r2, rs... PI, PZ, PS...

11,72,13

PI, P2, P3..

Tl, T2, T3... PI, P2, P3...

11, 12, 13

Tl, T2, T3... Pi, P2, PS...

Tl, T2, T3... PI, P2, PS....

I^oad

Compressive.

Transverse... Concentrated Impact

Raclcing

Transverse ii. Concentrated Impact

Transverse ^. Concentrated

Transverse >>- Concentrated,

Load

applied

Upper end.

Inside face. Outside face. Inside face. Near upper

end. Upper face. Do.

Do.

Do.

Do.

Do. Do.

» The concentrated and impact loads were applied to the same speci- m.ens, impact loads first. The transverse and concentrated loads were applied to the same

specimens, transverse loads first. The lateral deflections under compressive

loads were measured with a deflectometer of

fixed gage length, which consisted of a light

(duralumin) tubular frame having a leg at one end and a hinged plate at the other. The deflectometer in a vertical position was attached

to the specimen by clamping the hinged plate

to one of the faces near the upper end. The

gage length (distances between the points of

support) was 7 ft 6 in. A dial micrometer was

mounted on the frame at midlength, with the

spindle in contact with the wall specimen. The

dial was graduated to 0.001 in., and the readings were recorded to the nearest division. There

were two deflectometers on the specimen, one

near each outer stud. This method of measure- ment was used instead of the taut-wire mirrorscale method described in BMS2.

The indentation under concentrated load and

the set after the load was removed were measured, not the set only, as described in B]\IS2.

The apparatus is shown in figure 1.

Figure 1.Apparatus for com cnlrdlcil-load test. A, loading dislv; B, crossbar; C, dynamometer; D, stand; E, dial micrometer.

The load was applied to the steel disk, A, to which the crossbar, B, was rigidly attached.

Tlie load was measured by means of the dynamometer, C. Two stands, D, rested on the

face of the specimen, one over each of two adjacent transverse frame members. Each stand

supported a dial micrometer, E, the spindle of

which was in contact with the crossbar 8 in. from the center of the disk. The micrometers were graduated to 0.001 in., and the readings were recorded to the nearest division. The

initial reading (average of the micrometer

readings) was observed under the initial load,

which included the weight of the disk and

dynam.ometer. A load was applied to the disk

and the average of the micrometer readings

minus the initial reading was taken as the depth

of the indentation under load.

The deflections and sets under the impact

load were measured by means of two deflectometers and two set gages, not one of each as described in BAIS2. The deflectometers were

placed in contact with tlie unloaded face of the

[3]
specimen at midspan, one under each outer

longitudinal member, and the set gages rested one the loaded face, one over each outer longitudinal member. The readings, therefore, were

not affected by local deformations of the

plywood.

To distribute the load along the rackingspecimens, test fixtures were attached to the

top and bottom of the specimens. They were wood channels and extended the width of the

specimen. The web of each channel, a 2- by

8-in. white-oak plank, was fastened to each of two 2- by 4-in. Douglas-fir flanges by twenty

3}^-in. flat-head wood screws equally spaced.

The test fixtures were bolted to the top and

bottom of each racking specimen by seven

6K-in. carriage bolts, ji^ in. in diameter. Each

bolt extended through the flanges and throiigh a stud in the specimen. The fixtures were also fastened to the specimens by nineteen 3}^-in.

flat-head wood screws, equally spaced, extending tlxrough each flange into the specimen.

The deformations under racking loads were measured with a right-angle deformeter consisting of a steel channel and a steel angle

braced to form a rigid connection. The steel channel of the deformeter rested on the top test

fixture, the steel angle extenfling downward in

the plane of the specimen. Two nails extended

through the web of the steel channel into the

fixture. The bottom fixture was in contact

with the stop, to which a dial mircometer was

attached. The micrometer spindle was in contact with the steel angle of the deformeter.

Tlu^ gage length (distance from the top of the

specimen to the spindle) was 8 ft. in. The

micrometer was gradiiated to 0.001 in., and

readings were recorded to the nearest division.

The deformeter was used instead of the taut- wire mirror-scale device described in BMS2.

Figure 2.Longitudinal section through heal-transfer apparatus.

[4]
The tests were begun May 4, 1942, and completed May 20, 1942. The sponsor witnessed

the tests.

2. Heat Transfer

Three specimens representing the walls of a house and assigned the symbols IIT60, IITOl,

and HT62 were tested in a shielded bot-box

heat-transfer apparatus. The arrangement for the heat-transfer test is shown in figure 2. During a test, heat flowed from the metering

and guard boxes, which were heated electrically to the same temperature, to the cold box, which was cooled by a refrigerating machine. The

electric energy supplied to the metering box was

closely equivalent of the heat energy transferred

thi'ough the area to the specimen covered by the

metering box. The energy so supplied was

measured with a watthour meter; and this measurement, converted into Btu and divided

by the time, the area, and the temperature dif- ference, yielded the heat-transfer coefficient for the specimen.

By means of the guard box, the space sur- rounding the metering box was maintained at substantially the same temperature as its interior except on the side in contact with the

specimen. This minimized heat exchange to or from the metering box except thi'ough the specimen and subjected the face of the specimen not

covered by the metering box to au* at the same

temperature as that in the metering box.

The top and two vertical edges of the specimen projecting beyond the guard and cold

boxes were enclosed by an edge-shield, through

which air was circulated from the cold box at a temperature approximatmg the mean temperature of the specimen, in order to avoid heat gain

or moisture condensation at the edges from the

laboratory air. To promote uniformity of temperature, the

air within the boxes was given a gentle motion

by electric fans. The energy used by the fan in the metering box was added to that mtroduced

by the heating coils to arrive at the total energy

supplied.

Au" and specimen-surface temperatures were measured by copper-constantan thermocouples

in conjunction with a potentiometer. Recording

thermometers were used for approximate measm'ements of the interior temperatures of the

boxes during the period preceding each test when the apparatus was being brought to a

state of steady heat flow.

For testing, each specimen was placed m the

apparatus in the position shown in figure 2, and

the temperature m the cold box was adjusted as

closely as possible to 0° F and that in the

metering and guard boxes to 70° F. After a

state of steady heat flow was attained, the heat

transmission of the specimen, indicated by the

rate at which electric energy was supplied to the

metering box, was observed.

The heat-transfer measurement was made for an area 33 in. wide and 61 in. high, centrally

located on the face of the specimen, substantially covering the central eight cells formed by

the studs and girts. Theremocouples were

placed on both the warm and the cold faces of

the specimen to measure the temperatures of the surfaces over the aircells, over the studs, and

over a joint between a stud and a girt.

IV. MATERIALS

Unless otherwise stated, the information on

materials was obtained from the sponsor and

from inspection of the specimens. The Forest

Products Laboratoiy identified the species of

the wood, and the moisture content was determined by the Engineering Mechanics Section of

the National Bureau of Standards.

1. Wood

(a) Framing

The wood for the framing was identified as Douglas fu-, select, grade B and better, S4S

(surfaced fom- sides), in sizes by 2}^ in. (nominal 1 by 2)^ in.) and 1% by 3}^ in. (nominal

2 by 4 in.).

{h) Plywood, Moisture-Resistant Type

Douglas fir, and %-in., bonded with waterresistant protein glue having a soya-bean and

casein base, sanded two sides. The %-in. plywood was 3-ply, waUboard grade, and the

in. was 5-ply, S02S (sound two sides). The

ply^vood complied Commercial Standard

CS45-40. Douglas Fir Plywood Association

(%-in.) "Plywair and (,^^in.') "Plypanel."

[5]
(c) Plywood, Exterior Type

Douglas fir, %- and ^-in., bonded with hotpress synthetic-resin adhesive, sanded two

sides. The %-in. plywood was 3-ply and the

%-in. was 5-ply, both S02S, Ext. grade. The

plywood complied with Commercial Standard

CS45-40. Douglas Fir Plyivood Association

"Ext.-D.F.P.A."

After each specimen was tested, one face was removed to expose the framing, and samples of framing and plywood were cut for identification

J*

s

DR - Ti

I'KiLUi'^ \.--\\\M DR.

Typical specimen.
of the species. I'lgures 3 and 4 are typical

specimens.

Samples of plywood and framing were taken

from each specimen on the day the specimen was tested; they were weighed and then dried

to constant weight in an oven at 212° F. The

moistm'e content, given in table 2, was cal- culated on the oven-dry basis.

Table 2.A'loisture content of the wood

[Detormined on the day the wall, floor, or roof specimen was tested]

Wood

Framing, Douglas fir Do

Do

Do

Plywood, Douglas flr, moistureresistant type. Do

Do

Do

Plywood, Douglas flr, exterior type Do... DoDo

Construction symbol

DR.

DS. DT.

DU.

DR.

DS. DT.

DU.

DR.

DS. DT. DU

Moisture content

Mini- Maxi- mum mum

Percent Percent

5.9 8.2 6.5 8.9 8.3 in. 3 7.6 8.4

6.0 7.9

4.3 7.5

8.1 8.4

8.3 8.4

4.6 7.8 4.3 6.3 4.6 5.6 4.6 6.0

Average

Percent

7. 2 7.8 9,4

8.0

6.1 8.3

8.3

5.8

5.

1

5.0 5.3

2. Fastenings

(a) Nails

All nails were steel wire nails and are described m table 3.

Table 3.Description of the nails

Type

Common.

Do_..

Finishing, Lath

Penny

4

6

6

3

Length

2

2m

steel wire gage Diameter

No. in.

0. 0985 im . 113 13 . 0915

15 .072

Finish

Bright

do.

do. Blued.

Nails

per pound

316

181 309

778

(6) Corrugated Fasteners

Sheet steel, 1 in. long, K in. deep, No. 24

U. S. Standard Gage (0.0245 m. thick), live corrugations.

3. Glue

Urea-formaldehyde resin glue, powdered.

Casein Co. of America, "Cascamite."

V. STKUCTUllAL PROPEKTIES

1. Wall f)Ii

(a) SjMvmr's Statement

Wall DJi consisted of three sheets of Douglas

fii- plywood glued and nailed to two wood

flames. Pieces of pl3rwood were fastened between the frames and on the outer sui'faces of the frames to form the faces of the wall. These

frames, consisting of studs and girts, formed

closed cells between the sheets of plywood.

The price of this construction in Washington,

D. C, as of July 1937, was $0.37 IV.

(1) Four-Foot Wall Specimens

The 4-ft. wall specimens, shown in figure 5, were 8 ft 0 in. high, 4 ft 0 in. wide, and 2^}U in. thick. Each specimen had two like wood

frames to which three sheets of plywood were

fastened. Each frame consisted of tliree studs,

A, connected by seven lines of girts, B. The

middle sheet of plywood, C, outside face, D,

and inside face, E, each consisted of two pieces

of pljrwood. There was a longitudinal joint

in each sheet. Studs.—The studs, A, were Douglas fk,

25/32 by 2>^ m. (nomuial 1 by 2^ in.), 8 ft 0 m.

long, spaced 1 ft 4 in. on centers.

6^77^.9.—The girts, B, were Douglas fu', 25/32

by 2}i m. (nominal 1 by 2}^ in.), G^Yuin. and 1 ft 1% in. long, in seven transverse lines between

the studs. One line was spaced 1 ft 1% in. on

centers from the bottom line and the other lines

1 ft 4 ia. on centers. The girts were fastened

to the studs by corrugated fasteners, one on

each side at each intersection.

Middle sheet. —The middle sheet, C, was two

pieces of Douglas fir pljnvood, moisture-resis- tant type, % in. thick, 8 ft 0 in. long, and 2 ft 0 in. wide. The pieces were fastened to one frame by glue and nads. There was a longitudinal joint over the middle stud. The surface

of the frame in contact with the plTwood was

first coated with the glue niLxture applied with a brush. The mixture consisted of 2 parts glue

powder to 1 part water by volume or Iji parts

glue powder to 1 part water by weight. The

nails were 3d blued lath nails, one line of nails

along each stud and gu-t except at the longi521712°—43 2

[7]
tudinal joint, where there was a line in eaeli piece of plywood. In this construction all nails were spaced 4 in. The second frame was attached

to the middle sheet in the same manner by glue

and 4d common nails, along each stud and girt.

These nails extended through the second frame,

the plywood, and into the fu-st frame.

Outside face.—The outside face, D, was two

pieces of Douglas fu- plywood, exterior type,

% ill. thick, 8 ft 0 in. long, 8 iii. and 3 ft 4 in. wide. They were fastened by glue and nails to the frame, which had been coated with the

glue mixtm-e. The longitudinal joint in the

plywood was over an outer stud. The nails were 6d finishing nails, one line of nails along

each stud and girt except at the longitudinal

joint, where there was a Imc of nails in each

piece of plywood.

Inside jace.—The inside face, E, was similar

to the outside face except that the plywood was

of the moisture-resistant type. It was fastened

to a frame in the same manner as the outside

face except that the longitudinal joint was over

the other outer stud.

{2) Eight-Fitot Wall S-pecirnens

The 8-ft. wall specimens, shown in figure 6, were 8 ft 0 in. high, 8 ft 2}^ in. wide, and 2iK6 in. thick. The specimens were similar to the 4-ft specimens except for the following: The middle

sheet was two pieces of plywood 4 ft 0 in. wide.

The faces were each tlnec pieces of plywood

Figure 5.Four-fool wall DR.

A, stud; B, girt; C, plywood, middle sheet; D, plywood, outside face; E, plywood, inside face.

[8]
2 ft 8 in., 4 ft 0 in., and 1 ft 4 in. wide. The

longitudinal joints in the inside face were 1 ft 4 in. and 5 ft 4 in. from one edge and those in

the outside face the same distances from the

other edge.

(b) Compressive Load

Wall specimen DE-(^2 under compressive

load is shown in figure 7. The results for specimens DR-Cl, 02, and Cd arc given in liil>l(; 4 and in figures 8 and 9. The speed of the movable head of the t(!sting

machine under no load was adjusted to 0.07

in./min. The compressometor gage length was

8 ft 0 in. Under a load of 11 , 10.5, and 11.75 kips/ft on

specimens DR Cl , C2, and C3, respectively, the

inside faces began to buckle over each cell at

Figure 6.

Eight-foot ivall DR.

A, stud; B, girt; C, plywood, middle sheet; D, plywood, outside fiico; K. plywood, inside face.

[9]
Figure 7.—Wall specimen DR-C2 under compressive

load. A, doflpctometor; B, compressometer.

midheight. Under the maximum loads, the

inside faces buckled over most of the cells and

on specimens DR-Cl and C3 the load began to decrease with an increase of the lateral deflection. Under the maximum load, specimen

DR-C2 pushed out from under the loading

channel.

{c) Transverse Load

The results of the transverse load are shown

in table 4 and in figure 10 for wall specimens

DR-Tl, T2, and T3. The transverse loads were applied to the inside face. The speed of

the movable head of the testing machine was

^5

I ^

1 M

9

•

Li

1

\ OR

I

\

I

O .05 JO ./5

s/hor/en/ng /n./8f/' Figure 8.

Compressive load on wall DR.

Load-shortening (open circles) and load-set (solid circles) results for specimens DP-Cl, C2, and C3. The load was applied 0.90 in. (one- third the thicliness of the specimen) from the inside face. The loads

are in kips per foot of actual width of specimen.

9

8

7

6

5

4

3

/

O

B ~

o

-o—a—o—

pr-O

> f—o

• —

'cJ—o

» -<d/-o

h-——<9

I

/ OR O 0^ 0.4 0.6

/atera/ c/ef/ecf/on /n. Figure 9.

Compressive load on wall DR.

Load-lateral deflection (open circles) and load-lateral set (solid circles) results for specimens DR-Cl, C-2, and OS, The load was applied 0.90

in. (one-third the thickness of the specimen) from the inside face. The

loads are in kips per foot of actual width of specimen. The deflections and sets are for a gage length of 7 ft 6 in., the gage length of the deflectometers.

[10]
Table 4.

Structural properties of wall DR, floor DS, and roofs DT and DU

{Weight, based on face area: Wall DR, 4.38 Ib/ft^; floor DS, 8.15 Ib/ft^; roof DT, 7.96 lb/ft roof Z)f7, 8.H8 lb/ft>]

Oonstruction symbol

Average..

DS.

Average.

Average.

Average.

Compressive load

Specimen Maximum

load

b Kips/ft

11.80 11,02 12.50

11. 77

Transverse load

Specimen

Tl < TS < TS <

Tl >

\T1 < \T2i

[T3 <

TlT2K

TSI.

Maximum

load

Iblft^ 423 450

332

431 356

373

357

286

238

294

337 320 316

324

Concentrated load;

disk, 1 in. diam

Specimen

PI.

P2.

PS.

PI. P2.

PS.

PI. P2.

PS.

d 1, 000

<! 1,000

d 1,000

dl, 000 PI. P2.

PS.

<i 1, 000

i 1, 000

d 1, 000

"•1, 000

Maximum

load

d 1, 000

d 1, 000

d 1, 000

d 1, 000

d 1, 000

d 1, 000

d 1, 000

d 1, 000

Impact load; sandbag,

60 lb

Specimen

II12".

IS '.

Maximum

height of drop

dlO

d 10

d 10

d 10

d 10 dlO dlO

d 10

RackiiK-' load

Specimen

Rl.

Rt.

RS.

» The compressive loads were applied 0.90 in. (one-third the thickness of the specimen) from the inside face of the specimen.

b A kip is 1,000 lb. « Span 7 ft 6 in. d Test discontinued. • Span 12 ft 0 in. « Span 14 ft 0 in.

500

250

200

\^/50

%

^/OO

I

50

o

1m

OJL lO

DU O 0.5 10 /.5

c/ef/ecf/on /n.

£.0

Figure 10.

Transverse load on wall DR, load applied

to the inside face.

Load-deflection (open circles) and load-set (solid circles) results for specimens DR-Tl, T2, and TS on the span 7 ft 6 in. The load (pounds

per square foot) is the total load divided by the product of the span and the width of the specimen.

adjusted to 0.188 in./min. The effects of the transverse load are given in table 5.

Table 5.

Effects of transverse load on wall specimens

DR-Tl, T2, and TS, load applied on the inside face

Description of effects Speci- men Tl

Speci- men T2Speci- men TS

Ib ft » Buckling of loaded face at midspan 207 297 240 Failure in compression of plywood in loaded

face at midspan _ _ « 423 430 358 Rupture of plywood in unloaded face under a

loading roller ... ..

s 423 430 «388

Horizontal shear failure of outside stud under

a loading roller . . . . 450 «388

Maximum load on the specimen.

(o^) Concentrated Load

The results of the concentrated load are given

in table 4 and figure 11 for wall specimens

DR-Pl ,P2,mdPS. The concentrated load was

applied to the outside face midway between

two studs and 2 ft 1 in. from an end of the

specimen.

After a load of 1,000 lb had been applied, the

set in specimens DR-Pl, P2, and PS was 0.101,

0.070, and 0.072 in., respectively. No other

effects were observed.

[11]
/ndentat/on /n. Figure 11.

Concentrated load on wall DR, load applied

to the outside face.

Load-indentation (open circles) and load-set (solid circlec) results for specimens DR~P1, P2, and PS.

DR O 0.5 /.O /.5 def/ect/on /n. Figure 12.

Impact load on wall DR, load applied to the inside face.

Height of drop-deflection (open circles) and height of drop-set (solid

circles) results for specimens DP-Il, 12, and IS on the span 7 ft 6 in.

(e) Impact Load

The results of the impact load on wall speci- mens DR-Il, 12, and 13 are given in table 4

and in figure 12. The impact loads were applied to the center

of the inside face, the sandbag striking the

plywood directly over the center stud.

After a drop of 10 ft, the set in specimens

DR-Il, 12, and IS was 0.000, 0.004, and 0.002

in., respectively. No other effects were

observed.

(/) Racking Load

Wall specimen DR-R3 imder racking load

is shown in figure 13. The results of the rackFlGURE 13.—Wall speriir.en DU-l'.i under racking load. A, deformeter.

[12]
ing load on specimens DR-Rl, R2, and RS are given in table 4 and figure 14. To provide greater bearing for the loading

plate on specimen DR—Rl , the studs were sawed

olf flush with the plywood for 2 ft from the

top of the specimen. This reduced the studs

to % by 1 in. and thereby decreased their

strength.

5

4

I

I

J

•

/*

o

i

c 1 \ •

• — t cq / c 1—

/• • oo/ o

•

i

O Y o

• • •H• o pc

/

> O

Q/D

/ • 9

O 0.£ Q4

c/eformaf/on /n./8 ff- FiGUEE 14.

Racking load on wall DR.

Load-deformation (open circles) and load-set (solid circles) results for specimens DR-Bl, P£, and BS. The loads are in kips per foot of actual width of specimen. Under the maximum load on specimens

DR—Rl and R2, the studs adjacent to the loading plate failed 2 ft below the top of the specimen and both plywood faces ruptiu-ed near the

loading plate. After a load of 6.25 kips/ft

had been applied to specimen DR—R3 the test was discontinued. There was no visible damage.

2. Floor DS

(a) Sponsor's Statement

Floor DS consisted of tlii-ee sheets of Douglas

fir plywood glued and naUed to two wood

frames. One sheet of plywood was fastened

between the frames; the other two sheets were

fastened to the outer surfaces of the frames to form the flooring and the ceiling. The frames,

consisting of joists and solid bridging, formed

closed cells between the sheets of plywood.

The price of this construction in Washington, D. C, as of July 1937, was $0.47/ft^

(1) Description of Specimens

The floor specimens, shown in figure 15, were

13 ft 4 in. long, 4 ft 0 in. wide, and 8% in. thick. Each specimen had two like wood

frames to which three sheets of plywood were

fastened. Each frame consisted of tlu'ee joists,

A, connected by 11 lines of solid bridging, B.

The middle sheet of plywood, C, the flooring,

D, and ceiling, E, each consisted of five pieces

of plywood. All joints in the plywood were

butted joints. All longitudinal joints were on

joists and aU transverse joints were on solid

bridging. The joints in the three sheets were

staggered so that in the vertical plane through

a joint in one sheet there were no joints in the

other two sheets.

Joists. —The joists, A, were Douglas fir, 1%

by 3)^ in. (nominal 2 by 4 in.), 13 ft 4 in. long,

spaced 1 ft 4 in. on centers. Bridging.—The solid bridging, B, was Douglas fir, 1% by 3% in. (nominal 2 by 4 in.), 7% in. and 1 ft 2% in. long, placed in 11 lines between

the joists. One line was spaced 1 ft 2% in. on

centers from the line at one end of the specimen

and the other lines 1 ft 4 in. on centers. The

bridging was fastened to the studs by corru- gated fasteners, one on each side at each intersection.

Middle sheet.—The middle sheet, C, was five pieces of plywood, moisture-resistant type,

% in. thick and 2 ft 0 in. wide. The five pieces were fastened to one frame by glue and nails. The longitudinal joint was over the middle

joist. The middle sheet was offset longitudinally /8 in. from one end of the frame. The sur- face of the frame m contact with the plywood was first coated with the glue mixture applied

with a brush. The nails were 3d blued lath

nails, spaced 4 in., one line of naUs along each

joist and each line of bridging except at the

joints, where there was a line in each piece of plywood. The second frame was attached to the middle sheet in the same maimer b_v glue

and 6d common nails, spaced 8 in., along each

joist and line of bridging. These nails were

toenailed into the joists and bridgmg of the

[13]
Figure 15.

Floor DS.

.(4, joists; B, solid bridging; C, plywood, middle sheet; D, plywood flooring; E, plywood ceiling.

second frame and extended througli the middle

sheet into the first frame.

Flooring.—The flooring, D, was five pieces

of Douglas fir plywood, moisture-resistant

type, Yi. in. thick. Two pieces were 3 ft 4 in. wide and three were 8 ia. wide. They were

fastened by glue and naUs to a frame. The

longitudinal joint was over an outer joist.

The flooring was ofi^set longitudinaUy % in. from one end of the frame in the same direction as the middle sheet. The surface of the

frame in contact with the flooring was first coated with the glue mixture applied with a brush. The nails were 6d finishing nails,

spaced 4 in., one line of nails along each joist

and line of bridging except at the joints, where

there was a line of nails in each piece of plywood.

Ceiling.—The ceiling, E, was similar to the

flooring except that the plywood was exterior

type and % in. thick. It was fastened to the

frame in the same manner as the flooring except

that the longitudinal joint was centered over

the other outer joist.

(b) Transverse Load

The results of the transverse load for speci- mens DS-Tl, T2, and T3 are given in table 4

and in figure 16. The effects of the transverse load are given in table 6. The transverse loads

Table 6.

Effects of transverse load on floor specimens

DS-Tl, T2, and T3, load applied on the upper face

Speci- Speci- Speci- Description of efTects men men men

Tt T3 TS

Separation of a ceiling joint and cracking of W/ft 2 lb/ft' lb/ft 2 bridging directly over tiie joint 140 100 200 Separation of upper bridging from middle

sheet. - - . . - 242 429 319 Rupture of an 8-in.-wide ceUing sheet imder a

loading roller - ~ - - - - - 313 Horizontal shear failure of a lower joist be- tween loading rollers - - 292 400 313 Horizontal shear failure of upper joist between

loading rollers — 325 360 Maximum load .. 332 431 356

[14]
were applied to the upper face. The speed of

the movable head of the testing machine was

adjusted to 0.17 in./min.

300

c/ef/ecf-fon /n. Figure 16.—Transverse load on floor DS, load applied

to the upper face

I.oad-deflection (open circles) and load-set (solid circles) results for speci- mens DS-Tl, T2, and TS on the span 12 ft 0 in. The load (pounds

per square foot) is the total load divided by the product of the span and

the width of the specimen.

Floor specimen DS-Tl after the transverse

test is shown in figures 17 and 18 and specimen DS-T2 in figure 19.

(c) Concentrated Load

The results of the concentrated load on speci- mens DS-Pl, P2, and P3 are given in table 4

and figure 20. The concentrated load was applied to the vipper face midway between joists

and 3 ft 4 in. from one end of the specimen. It was applied at the middle of a cell. After a load of 1,000 lb had been applied,

the set in specimens DS-Pl, P2, and P3 was

0.041, 0.042, and 0.043 in., respectively. No

other effect was observed.

(d) Impact Load

Floor specunen DS-I2 during the impact

test is sho-wai in figure 21. The results for

specimens DS-Il, 12, and IS are given in

table 4 and figure 22. The impact loads were applied to the center

of the upper face, the sandbag strilving the plywood over the center joist and bridging.

After a drop of 10 ft the set in specimens

DS-Il, 12, and 13 was 0.000, 0.007, and 0.043

in., respectively. No other effect was obsei'ved

FiGL'RE 17.

Floor specimen DS-Tl after the transverse test. The upper joist and the upper solid bridging have separated from the middle sheet of plywood.

521712°—4,3 3 [15]
FiGUKE 18.

Floor specimen DS-Tl after the transverse test. The upper joist and the upper solid bridging have separated from the middle sheet of plywood. The piece of plywood in the lower face was

forced down when the lower joist failed.

^600

I

O'

1 *

/ — /•

/ -9

/

1ULn

FT

U

f OS o

Figure 19.

Floor s-pecimen DS-T2 after the transverse

test. The butted joint in the lower sheet of plywood failed when the solid bridging failed in tension across the grain, and, when the lower joist failed, the piece at the left was forced down, palling the nails from the bridging and the joist.

a/

/ndentat/on /n. Concentrated load on floor DS, load applied

to the upper face.

Load-indentation (open circles) and load-set (solid circles) results for specimens DS~P1, P£, and PS.

FiGUKK 20.-

16
Figure 21.

Floor specimen DS-I2 during the impact test.

A, deflectometer; B, set gage

V

o

Figure 22.-

Q^ 0.4 0.6 0.3 def/ecf/'on j'n

-Impact load on floor DS, load applied to the upper face.

Height of drop-deflection (open circles) and height of drop-set (solid

circles) results for specimens DS-Il, 12, and 1.3 on the span 12 ft 0 in The load (pounds per square foot) is the total load divided by the product of the span and the width of the specimen.

3. Roof DT

(a) Sponsor's Statement

Roof Z^r consisted of three sheets of Douglas

fir plywood glued and nailed to two wood frames.

One sheet of plywood was fastened between the

frames; the other two sheets were fastened to the outer surfaces of the frames to form the

roofuig and the ceiling. The frames, consisting

of rafters and solid bridgmg, fonned closed

cells between the sheets of plywood.

The price of this construction m Washington,

D. C, as of July 1937, was SO.SS/ft^.

(i) Description of Specimens

The roof DT, shown in figure 23, was shnilar

to floor DS except for the following: The speci- mens were 14 ft 8 m. long (not 13 ft 4 in.) and

there were 12 luaes of solid bridging between

rafters (not 11). The roofing, D, was of exteriortype plywood and the ceUmg, E, of the moistureresistant type.

(6) Transverse Load

The results of the transverse load on roof

specimens DT-Tl, T2, and T3 are given in table 4 and figure 24. The transverse loads

[17]
were applied to the upper face. The speed of the movable head of the testmg machine was

adjusted to 0.21 in./min.

Under a load of 171, 213, and 123 lb/ft- on

specimens DT-Tl, T2, and T3, respectively, a

transverse joint in the ceiUng began to separate, and cii-acks appeared in the bridging diI'ectly over the transverse joint. Under a load

of 357 lb/ft2 for specimen DT-Tl, 279 lb/ft' for T2, and 200 Ib/ft^ for T3, the upper bridging

and rafters separated from the middle sheet. Under the maximum load, an upper and a lower

I'after in specimen Tl failed in horizontal shear

between the loading jollers and a lower rafter in

specimens T2 and T3 failed under one loading

loUer.

Roof specimen DT-Tl after the transverse

test is shown in figures 25 and 26.

(c) Concentrated Load

The results of the concentrated load on ]-oof specimens DT-Pl, P2, and P3 are given in

table 4 and figui-e 27.

The concentrated load was apphed at the

middle of a cell to the upper face midway between two rafters and 3 ft 4 in. from one end

of the specimen.

After a load of 1,000 lb had been applied, the

set in specimens DT-Pl, P2, and P3 was

0.021, 0.030, and 0.027 in., respectively. No

other effects were observed.

4. Roof Z>C7

(a) S'ponsor's Statement

Roof DL was a demountable construction

consisting of three sheets of Douglas fir plywood glued and nailed to two wood frames.

One sheet of plywood was fastened between the

frames; the other two sheets were fastened to the outer surfaces of the fi-ames to form the

roofing and the ceiling. The frames, consisting

of i-afters and solid bridging, formed closed cells between the plywood.

The price of this construction in "Washington,

D. C, as of July, 1937, was $0.53/ft^
0.5 /.O

o'ef/ecf/on /n.

/.5

Figure 24.

Transverse load on roof DT, load applied to the upper face.

I/Oad-deflection (open circles) and load-set (solid circles) results for specimens DT-Tl, T2, and TS on the span 14 ft 0 in. The load (pounds per square foot) is the total load divided by the product of the span and the width of the specimen.

Figure 25.

Roof specimen DT-Tl after the transverse

test. The butted joint in the lower sheet of plywood failed when the solid bridging failed.

FiGURK 2(i.

Roof specimen DT-Tl after the transverse

test. The butteil joint in the lower sheet of plywood failed wlicn the solid bridging failed.

^600

200*

0

6»

/ z:

/ -®

/

/e

1•

»

•

eU

*-P H

u

or O .05 ./O ./5 .20

/nc/enf-at/on /n.

Figure 27.

Concentrated load on roof DT, load applied

lo the upper face.

Load-indentation (open circles) and load-set (solid circles) results for specimens DT~P1, I\>, and PS.

[19]
(1) Description oj Specimens (b) Transverse Load

The roof DU, shown in figure 28, was similar

to roof DT except for the following: The speci- mens were 6% in. thick (not 8% in) . The thick- ness was less than that for roof 7)T because the

rafters and bridging in the upper frame were

flatwise (not edgewise).

The middle sheet of plywood first was fast- ened to the lower frame (rafters -and bridging

edgewise) as for floor DS and roof DT, then to the i:pper frame (rafters and bridging flatwise),

by glue and nails extending tlu-ough the plywood adjacent to the members of the lower

frame and into the upper frame. There were no toenails in roof DU.

Each sheet consisted of three pieces of plywood with two continuous transverse joints.

There were no longitudinal joints. The roofing,

middle sheet, and ceiling were offset 1% in. both

longitudinally and laterally; the roofing and

ceiling in opposite directions from the middle

sheet. In a demountable house the wall, fioor,

and roof panels are connected by inserting the

tongues on one panel into grooves in the other.

Roof specimen DU-T2 under transverse load

is shown in figure 29. The results of the transverse load on speci- mens DU-Tl, T2, and T3 are given in table 4 and figure 30. The transverse load was applied to the upper

face. The speed of the movable head of the

testing machine was adjusted to 0.27 in./min.

Under loads of 261, 246, and 200 Ib/ft^ for specimens DU-Tl, T2, and T3, respectively, a transverse joint in the ceiling began to separate.

A piece of the ceiling on specimen T2 separated

from the lower rafters under a load of 284 Ib/ft^, and a piece of the middle sheet on specimen T3

separated from the lower rafters under a load

of 289 Ib/ft^. Under the maximum load on

specimen Tl, the lower rafters separated from

the middle sheet and ceiling and a lower rafter

failed in horizontal shear between the loading

rollers. In specimen T2 under the maximum

load, a piece of the middle sheet separated from

the lower rafters and a lower rafter ruptured at midspan. Under the maximum load on specFiGURE 28.—i?oo/ D U.

A, rafters; B, solid bridging; C, plywood, middle sheet; J), plywood roofing; E, plywood ceiling

20
Figure 29.

Roof specimen DU-T2 under transverse load.

imen T3, the two outer lower rafters failed in

horizontal shear under a loading roller.

(c) Concentrated Load

The results of the concentrated load on roof

specimens DU-Pl, P2, and P3 are given in

table 4 and figure 31. The concentrated load was applied to the upper face midway between

two rafters and 3 ft 4 in. from an end of the

specimen. It was applied at the middle of a

cell.After a load of 1,000 lb had been applied,

the set in specimens DU-Pl, P2, and PS was

0.022, 0.038, and 0.040 in., respectively. No

other effects were observed.

VI. HEAT-TRANSFER PROPERTIES

1. Walls HT60, HT61, and HT62

Walls HT60, HT61, and HT62 consisted of

three sheets of Douglas fir plywood glued and

nailed to two wood frames. One sheet of

plywood was fastened between the frames; the

other two sheets were fastened to the outer

surfaces of the frames for the faces of the waU.

The frames, consisting of studs and girts,

formed closed cells between the plywood.

These closed air cells provided thermal insulation. The price of this construction in Washington,

D. C, as of July 1937, was $0.37/ft

(a) Description of Specimens

Walls HT60, HT61, and HT62 were identical with waU DR except for the aluminum

paint. Specimen HT60, shown in figure 32, was 8 ft 0 m. high, 5 ft 4 in. wide, and 2i}(6

in. thick. There were five studs m each frame.

One coat of aluminum paint was applied to each surface of the middle sheet of plj^wood.

Specimen HT61 was identical with HT60

except that two coats of the same paint were

applied on the warm-side sin-face of the middle

[21]
300

250

\^ /50

^ /oo

I

50

o

• o

\•

»

>

»

o y

Y OR

O 0.5 15

def/ect/on /n. Figure 30.

Transverse load on roof DU, load applied to the upper face.

Load-deflection (open circles) and load-set (solid circles) rosiiHs for specimens DV-Tl, Tf, and TS on the span 14 ft 0 in. The load (pounds per square foot) is the total load divided by the product of the span and the width of the specimen.

800

200s

O

r~—®—®— a-—>rO- -o

% ®

/

/«e

1m

a

» a

» <n>-

J I

DU O .05 JO ./5 .20

Jndenfat/on /n. Figure 31.

Concentrated load on roof DU, load applied

to the upper face.

Load-indentation (open circles) and load-set (solid circles) results for specimens D U-Pl, P2, and P.3.

sheet of plywood. There was no paint on the

cold-side surface.

Specimen HT62 was identical with HT60

except that there was no paint on this specimen.

(b) Test Results

The results of the heat-transfer tests are

o-iven in table 7.

Table 7.

Heat-transfer coefjireints and test data for wall specimens HT60'. HT61, and HT62

Item » HT60

Observed thermal transmittance u. Corrcctcil I licrinal transmittance U- ThoniKil foniluctance ..C Warm surface film conductance fi. Cold surface film conductance /o. Temperature averages: Warm side: Air

Surface over air space

Surface over stud

Surface over frame joint . Surface, weighted average __. Cold side: Air

Surface over air space

Surface o\'er stud

Surface over frame joint Surface, weighted average _ Temperature differences: Air to air Surface to surface Surface to air, warm .side _ Surface to air, cold side

0.20

.22

.26

1.91 1.64

70.5

64.

60.5

56.6

63.1

0.0

7.8

10.7

13.2

70.5

54.5

7.4

HT61

0. 22

. 24 .30 1.96 1.62

op

70.5

63.3 60.0

57.0 62.4 -0.3

9.1 10.1 13.8 9.5

70.8

52.9

8.1

HT62

0.24

.20

.33 1.96

1.57

70.5

62.7 59.9

56.0

61.9 -0.6

8.7

11.2

12.9

10. 1

71.1

51.8 8.6

10.7

» 'l^he definitions of u, U, and C, representing the various coefHcients of heat transmission, are: i/=number of Btu per hour transmitted through each square foot of specimen for each degree Fahrenheit difference in temperature be- tween the air on the two sides, as otaserved under the test conditions. U=u corrected for a 15-mph wind outside and zero wind inside by

means of the factors /!=-l. 65 and/o=6.00, taken from the ASHVE

"Guide." r'=number of Btu transmitted through each square foot of specimen for each degree Fahrenheit difference in temperature between the

surfaces of the two sides as observed under the test conditions.

In this table the heat transmission of the

specimen is expressed in three ways. Two in- clude the effect of surface-film coefficients, and

the third is mdependent of them. The first result, u, is the thermal transmittance of the

specimen as observed under test conditions.

Under these conditions, the warm-surface-film

conductance, Ji, and the cold-surface-film con- ductance /o, were those given in the table. Since the air velocity and its effect on the two

surfaces of the specimen may not be the same

for different conditions, it seemed desirable to correct the observed thermal transmittance for a wind velocity of 15 mph on the outside face

of the wall and zero velocity on the inside face,

by means of the factors 7?= 1.65 and/o =6.00, as recommended in the ASHVE "Guide."

[22]
The thermal conductance, C, of the spociuKMi

is also presented, and this represents the nunil)er

of Btu per hour transmitted through each square

foot of specimen for each degree Fahrenheit

difference in temperature betw^een the surfaces

of the two sides as observed under the test conditions.

The test data show that the surface temperatures of the specimens over intersections of studs and girts were considerably lower on the

warm side and higher on the cold side than the

surface temperatures over the studs. Since

there were eight corrugated metal fasteners at each of these intersections, it is evident that the

conductance at each frame joint was increased

considerably by the presence of the fasteners.

Tlie (hita also indicate by the diUVi-cnccs in

tlie temperatures of tlie surfaccss over the air

cells aufl over the studs tliat the conductance

through the studs is greater than the (•oii(liict- ance across the air cells in the wall. Altlioiigli some improvement in this respect might be

accomplished by staggering the studs and girts on the two sides of the middle sheet of plywood,

the complications that would be entailed from

a construction standpoint might far outweigh

the improvement in insulating value that could

be attained.

The U value of a wall construction such

as HT62, with no reflective surfaces, as computed by means of the factors listed in the

ASHVE "Guide," is 0.252. The test result is

HT60

Figure 32.— TTV/// HT60.

A, studs; B, girts; C, plywood, middle shed; D, plywood, outside face; E, plywood, inside face.

[23]
in agreement with this computed value of ?7aQd

is sliglitly higlier, probably because of the large

conductance through the joints of the specimen

which is not taken into account in the

computed U value.

The values of the corrected thermal trans- mittance, U, before being rounded to two significant figures, as presented in the table, Avere 0.217, 0.244, and 0.260 for specimens IITGO,

HTei, and HT62, respectively. From these

values it can be calculated that two coats of the aluminum paint applied on the warm-side

surface of the middle sheet of plywood reduced

the U value by 6 percent ; and that one coat of paint on each face of the middle pljnvoocl sheet

reduced the ?7 value by 16 percent, or 8 percent

for each painted face. Apparently, one coat

of the paint was more effective than two applied one over the other. Variability in the matexials

composing the specimens or in details of their

assembly may have contributed to this result. However, a possible explanation for the apparent greater eft'ectiveness of single coats of paint is that a relatively larger proportion of

the vehicle of the paint is absorbed into the

wood in the case of a first coat than is absorbed

when a second coat is applied over the first. Since the thermal reflectivity of the surface

depends upon the flake surfaces being coated

with as little vehicle as possible, one coat may

provide the most reflective surface. The test result is not conclusive, but it is an indication

that there is no economy in applyitig more than one coat of paint.

VIL ADDITIONAL COMMENTS BY

SPONSOR

Several years ago, one house using this type

of construction was built ia Florida. Since

then some of the details of connections have

been revised with a view to simplifying and

unproving the methods of erection.

At the present time the construction is designed to be erected on any convential type of masonry foimdation. One special design uses three concrete walls as foundation, one under

the middle and two along the sides of the building, the ends open.

Figure 33.

Section of a typical "Multiple Box-Girder Plywood PaneV hoiise.

[24]
To increase the strength of the transverse

joints in the plywood faces the design has been

changed to have a strip of plywood about 8 in. wide at the joints along the solid bridging. The

pieces of plywood will be butted at midwidth

of the strip. From the standpoint of fabrication, the strip of plywood is preferable to a

scarfed jomt in the faces. The waterproof adhesive used m fabricating

the plywood and the waterproof glue used m

joining the sections withstand exposure to the

weather.

Partitions are similar to walls except that the

frames are made from material 1% in. thick.

The frames in partitions are thicker than those

in walls because the loads are greater.

The thiclmess of the frames is sufficient to permit the installation of concealed pipes, ducts,

and conduits.

A section of a typical liouse is shown in figure 33.

The descriptions and drawings Avere prepared

by E. J. Schell and G. W. Shaw, of the Building

Practices and Specifications Section, under the

supervision of V. B. Plielan.

The heat-transfer properties Avere determined

by H. E. Robinson, of the Heat Transfer Section, under the supervision of R. S. Dill. The structural properties were determined

by the Engineering Mechanics Section, under

the supervision of H. L. Wliittemore and W. G.

Hoback, with the assistance of H. O. Best,

R. Goldberg, E. I. Peizer, L. R. Swectman, and

H. L. Weiss.

Washington, SeptemlMT 17, 1942.

[25]

BUILDING MATERIALS AND STRUCTURES REPORTS

[Continued from cover page II] BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block Wall Construction Sponsored by the National Concrete Masonry Association. 10^ BMS33 Plastic Calking Materials 10^ BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 10^ BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging 100 BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions

with "Red Stripe" Lath Sponsored by The Weston Paper and Manufacturing Co.- 100 BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors Sponsored by Palisade Homes 100 BMS38 Structural Properties of Two "Dunstone" WaU Constructions Sponsored by the W. E. Dunn Manufacturing Co 100 BMS39 Structural Properties of a WaU Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co --1O0 BMS40 Structural Properties of a Wall Construction of "Knap Concrete WaU Units" Sponsored

by Knap America Inc 100 BMS41 Effect of Heating and Cooling on the Permeability of Masonry WaUs 100 BMS42 Structural Properties of Wood-Frame WaU and Partition Constructions with "Celotex"

Insulating Boards Sponsored by The Celotex Corporation 150 BMS43 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 100 BMS44 Surface Treatment of Steel Prior to Painting 100 BMS45 Air Infiltration Through Windows 100 BMS46 Structural Properties of "Scot-Bilt" Prefabricated Sheet-Steel Constructions for Walls,

Floors, and Roofs Sponsored by The Globe-Wernicke Co 100 BMS47 Structural Properties of Prefabricated Wood-Frame Constructions for WaUs, Partitions,

and Floors Sponsored by American Houses, Inc 100 BMS48 Structural Properties of "Precision-BuUt" Frame WaU and Partition Constructions

Sponsored by the Homasote Co 100 BMS49 Metallic Roofing for Low-Cost House Construction 100 BMS50 Stability of Fiber BuUding Boards as Determined by Accelerated Aging 100 BMS51 Structural Properties of "Tilecrete Type A" Floor Construction Sponsored by the

Tilecrete Co 100 BMS52 Effect of Ceiling Insulation Upon Summer Comfort 100 BMS53 Structural Properties of a Masonry Wall Construction of "Munlock Dry WaU Brick"

Sponsored by the Munlock Engineering Co 100 BMS54 Efifect of Soot on the Rating of an OU-Fired Heating Boiler 100 BMS55 Effects of Wetting and Drying on the Permeability of Masonry Walls 100 BMS56 A Survey of Humidities in Residences 100 BMS57 Roofing in the L^nited States—Results of a Questionnaire 100 BMS58 Strength of Soft-Soldered Joints in Copper Tubing 100 BMS59 Properties of Adhesives for Floor Coverings 100 BMS60 Strength, Absorption, and Resistance to Laboratory Freezing and Thawing of BuUding

Bricks Produced in the United States 150 BMS61 Structural Properties of Two Nonreinforced Monolithic Concrete WaU Constructions 100 BMS62 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by the Portland Cement Association 100 BMS63 Moisture Condensation in Building WaUs 100 BMS64 Solar Heating of Various Surfaces 100 BMS65 Methods of Estimating Loads in Plumbing Systems 100 BMS66 Plumbing Manual 200 BMS67 Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for WaUs,

Partitions, Floors, and Roofs Sponsored by Herman A. Mugler 150 BMS68 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 3 150 BMS69 Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 100 BMS70 Asphalt-Prepared RoU Roofings and Shingles 150 BMS71 Fire Tests of Wood- and Metal-Framed Partitions 200 BMS72 Structural Properties of "Precision-BuUt, Jr." Prefabricated Wood-Frame WaU Construction Sponsored by the Homasote Co 100 BMS73 Indentation Characteristics of Floor Coverings 100 BMS74 Structural and Heat-Transfer Properties of "U. S. S. PanelbUt" Prefabricated SheetSteel Constructions for Walls, Partitions, and Roofs Sponsored by the Tennessee

Coal, Iron & Railroad Co 150 BMS75 Survey of Roofing Materials in the North Central States 150 BMS76 Effect of Outdoor Exposure on the Water PermeabUity of Masonry WaUs 150 BMS77 Properties and Performance of Fiber TUe Boards 100 BMS78 Structural, Heat-Transfer, and Water-PermeabiUty Properties of Five Earth-WaU

Constructions 200 BMS79 Water-Distributing Systems for Buildings 150

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

[Continued from cover page in]

BMS80 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 4 15^5 BMS81 Field Inspectors' Check List for Building Construction (cloth cover, 5 x 7J4 inches) 20^

BMS82 Water Permeability of Walls Built of Masonry Units 20^

BMS83 Strength of Sleeve Joints in Copper Tubing Made With Various Lead-Base Solders 10^ BMS84 Survey of Roofing Materials in the South Central States 15^ BMS85 Dimensional Changes of Floor Coverings with Changes in Relative Humidity and

Temperature 100 BMS86 Structural, Heat-Transfer, and Water-Permeability Properties of "Speedbrik" Wall

Construction Sponsored by the General Shale Products Corporation 150 BMS87 A Method for Developing Specifications for Building Construction 100 BMS88 Recommended Building Code Requirements for New Dwelling Construction with Special

Reference to War Housing 200 BMS89 Structural Properties of "Precision-Built, Jr." (Second Construction) Prefabricated

Wood-Frame Wall Construction Sponsored by the Homasote Co 150 BMS90 Structural Properties of "PHC" Prefabricated Wood-Frame Constructions for Walls,

Floors, and Roofs Sponsored by the PHC Housing Corporation 150 BMS91 A Glossary of Housing Terms 150 BMS92 Fire-Resistance Classifications of Building Constructions 250 BMS93 Accumulation of Moisture in Walls of Frame Construction During Winter Exposure 100 BMS94 Water Permeability and Weathering Resistance of Stucco-Faced, Gunite-Faced, and

"Knap Concrete-Unit" Walls 100 BMS95 Tests of Cement-Water Paints and Other Waterproofings for Unit-Masonry WaUs 150 BMS96 Properties of a Porous Concrete of Cement and Uniform-Sized Gravel 100 BMS97 Experimental Dry-Wall Construction with Fiber Insulating Board 100 BMS99 Structural and Heat-Transfer Properties of "Multiple Box-Girder Plywood Panels" for Walls, Floors, and Roofs Sponsored by Loren H. Wittner 150