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.S. DEPARTMENT OF COMMER,

National Bureau of Standards

NAT'L INST. OF STAND & TECH

A111D7 2MH2E3

TBS Technical Note 1205

earances and Methods of Protection

for Wall and Ceiling Surfaces Exposed

to Radiant Heating Appliances !

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The National Bureau of Standards' was established by an act of Congress on March 3, 1901. The

Bureau's overall goal is to strengthen and advance the nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a

basis for the nation's physical measurement system, (2) scientific and technological services for industry and

government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety.

The Bureau's technical work is performed by the National Measurement Laboratory, the National

Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Center for Materials

Science.

The National Measurement Laboratory

Provides the national system of physical and chemical measurement;

coordinates the system with measurement systems of other nations and

furnishes essential services leading to accurate and uniform physical and

chemical measurement throughout the Nation's scientific community, in- dustry, and commerce; provides advisory and research services to other Government agencies; conducts physical and chemical research; develops,

produces, and distributes Standard Reference 'Materials; and provides

calibration services. The Laboratory consists of the following centers:

• Basic Standards2

• Radiation Research

• Chemical Physics

• Analytical Chemistry

The National Engineering Laboratory

Provides technology and technical services to the public and private sectors to address national needs and to solve national problems; conducts research in engineering and applied science in support of these efforts; builds and maintains competence in the necessary disciplines required to carry out this research and technical service; develops engineering data and measurement

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and proposes new engineering practices; and develops and improves

mechanisms to transfer results of its research to the ultimate user. The

Laboratory consists of the following centers:

Applied Mathematics

Electronics and Electrical Engineering2 Manufacturing Engineering

Building Technology

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Chemical Engineering2

The Institute for Computer Sciences and Technology

Conducts research and provides scientific and technical services to aid Federal agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and economy in Government

operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders, and other directives; carries out this mission by managing

the Federal Information Processing Standards Program, developing Federal ADP standards guidelines, and managing Federal participation in ADP

voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal agencies; and provides the technical foundation for computer-related policies of the Federal Government. The Institute consists of the following centers:

Programming Science and

Technology

Computer Systems

Engineering

The Center for Materials Science

Conducts research and provides measurements, data, standards, reference

materials, quantitative understanding and other technical information funda- mental to the processing, structure, properties and performance of materials; addresses the scientific basis for new advanced materials technologies; plans

research around cross-country scientific themes such as nondestructive

evaluation and phase diagram development; oversees Bureau-wide technical programs in nuclear reactor radiation research and nondestructive evaluation; and broadly disseminates generic technical information resulting from

its programs. The Center consists of the following Divisions:

Inorganic Materials Fracture and Deformation"

Polymers

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Iquariers and Laboratories at Gailhersburg, MD, unless otherwise noted; mailing address

Gaiihersburg, MD 20899.

ne divisions within the center are located at Boulder, CO 80303.

B i Idi i CO, with some elements at (jaithcrsburi> MD.
NBS Technical Note 1205

NATIONAL BUREAU

OF STANDARDS

LIBRARY

aGearances and Methods of Protection

for Wall and Ceiling Surfaces Exposed

to Radiant Heating Appliances

Joseph J. Loftus Sponsored in part by:

Richard D. Peacock U.S. Department of Energy

Washington, DO 20585

Center for Fire Research and

National Engineering Laboratory U.S. Consumer Product Safety Commission

National Bureau of Standards Washington, DC 20207

Gaithersburg, MD 20899

Issued December 1984

•</,'"EAU o*

U.S. Department of Commerce

Malcolm Baldrige, Secretary National Bureau of Standards

Ernest Ambler, Director
National Bureau of Standards U.S. Government Printing Office For sale by the Superintendent

Technical Note 1205 Washington: 1984 of Documents

,

Natl. Bur. Stand. (U.S.), U.S. Government Printing Office

,

Tech. Note 1205, 112 pages Washington, DC 20402

(Dec. 1984)

CODEN: NBTNAE
TABLE OF CONTENTS

Page

LIST OF TABLES v

LIST OF FIGURES vi

Abbreviation Key to Tables ix

Abstract 1

1

.

INTRODUCTION 2

2. BACKGROUND 3

3. REVIEW OF PREVIOUS WORK 5

3.1 Minimum Safe Clearances in Existing Codes and Standards .. 5

3.2 Temperatures Developed in Heating Systems 7 3.3 Limiting Safe Temperatures on Combustible Surfaces 9

PART I. SYSTEMS FOR PROTECTING WALL SURFACES EXPOSED TO RADIANT

APPLIANCES 11

4. WALL PROTECTION SYSTEMS 12

5. TEST APPARATUS 14

6. TEST PROCEDURES 15

7. TEST RESULTS AND DISCUSSION 16

7.1 Unprotected Gypsum Wallboard - Painted Versus Unpainted

Surfaces 17

7.2 Effect of a Metal Protector and Air Space on Wallboard

Surface Temperature 18

7.3 Effect of Black Painted Metal Protector and Air Space on Wallboard Surface Temperature 18

7.4 Effect of Black Painted Metal Protectors and Air Space on Black Painted Wallboard 19

7.5 Effect of Protective Devices Attached Directly to

Wallboard 21

7 .6 Effect of Air Space Combined with Protective Insulating

Boards, and a Brick Wall on Wallboard 22

7.7 Effect of Black Painted Metal Sandwich Panels and Air

Space on Wallboard Surface Temperature 23

8. SUMMARY OF RESULTS 23

9. OBSERVATIONS 24

10. CONCLUSIONS 27

-iii-
Table of Contents (continued)

Page

PART II. SYSTEMS FOR PROTECTING WALL AND CEILING SURFACES EXPOSED

TO HEATING APPLIANCE CHIMNEY CONNECTORS 41

11. TEST APPARATUS FOR CHIMNEY CONNECTOR TESTS 42

12. TESTING PROGRAM 43

12.1 Test Systems 43

12.2 Test Criteria 44

13. TEST RESULTS 45

13.1 Unprotected Ceiling Panel Tests 45

13.2 Protected Ceiling Panels - With Air Circulation Around

the Black Painted Ceiling Protector Plate 46

13.3 Protected Ceiling Panels - With Air Circulation Around

an Unpainted Ceiling Protector Plate 46

13.4 Protected Ceiling Panels - With Air Circulation Around

a White Painted Ceiling Protector Plate 47

13.5 Protected Ceiling Panels - With No Air Circulation

Around the White Painted Ceiling Protector Plate 47

14. SUMMARY OF RESULTS 48

15. TEST OBSERVATIONS 49

16. CONCLUSIONS 50

PART III. FULL ROOM VALIDATION OF WALL AND CEILING DEVICES FOR

HEATING APPLIANCE AND CHIMNEY CONNECTOR SYSTEMS 60

17. FULL ROOM TESTS 62

18. TEST ROOM SET UP 62

19. TESTING PROGRAM 63

19.1 Test Systems 63

19.2 Test Criteria 64

20. TEST RESULTS 65

20.1 Walls 65

20.2 Ceilings 65

21. TEST OBSERVATIONS 66

21.1 Room Walls 66

21.2 Room Ceilings 67

22. CONCLUSIONS 68

23. RECOMMENDATIONS 69

24. REFERENCES 100

-iv-
LIST OF TABLES

Page

Part I

Table 1 . Twenty-three Wall Protection Systems Tested 29

KEY to Table 1 30

Table 2. Temperature Rise Above Room Temperature for Protector and

Gypsum Wallboard Surfaces for "Worst-Case" Conditions 31

Part II

Table 3 . Nineteen Wall-Ceiling Systems Tested 52

Key to Table 3 53

Table 4. Wallboard Surface Temperature Rise Measured During Tests

of Chimney Connector/Wall Protection Systems 54

Part III

Table 5. Fourteen Room Wall- Ceiling Systems Tested 72

Table 6. Range of Surface Temperature Rise Along the Horizontal

and Vertical Planes of Room Walls 73

Table 7. Minimum Clearance Needed Between Appliance and

Exposed Wall Surfaces to Meet Code Requirements 75

Table 8. Systems Showing High Ceiling Surface Temperatures At

Overfire Conditions 76

Table 9. Reduction of Appliance Clearances with Specified Forms

of Protection 77

NOTES - Table 9 78

-v-
LIST OF FIGURES

Page

Part I

Figure 1. Appliance Construction Details for Gas Fired Stove

Used in Wall Protection Tests 32

Figure 2 . Thermocouple Placement on Appliance Surface 33

Figure 3. Thermocouple Placement on Protector and Wallboard

Surface 34

Figure A. Temperature Rise on Gypsum Wallboard Surfaces

(Unprotected-Protected) Exposed to Temperatures of

150, 200, 250, 300 and 350°C, Systems 1-5 35

Figure 5. Temperature Rise on Gypsum Wallboard Surfaces

(Unprotected-Protected) Exposed to Temperatures of

150, 200, 250, 300 and 350°C, Systems 6-10 36

Figure 6. Temperature Rise on Gypsum Wallboard Surfaces

(Unprotected-Protected) Exposed to Temperatures of

150, 200, 250, 300 and 350°C, Systems 11-15 37

Figure 7. Temperature Rise on Gypsum Wallboard Surfaces

(Unprotected-Protected) Exposed to Temperatures of

150, 200, 250, 300 and 350°C, Systems 16-20 38

Figure 8. Temperature Rise on Gypsum Wallboard Surfaces

(Unprotected-Protected) Exposed to Temperatures of

150, 200, 250, 300 and 350°C, Systems 21-23 39

Figure 9. Surface Temperature Rise and Clearances for (Protected)

Gypsum Wallboard Exposed to 350°C Stove Temperature 40

Part II

Figure 10. Relation of Stove and Ceiling Connector Pipe System to

Wall and Ceiling Panels 55

Figure 11. Vertical Wall Panel Thermocouple Locations 56

Figure 12. Ceiling Panel Thermocouple Locations 57

Figure 13. Temperature Rise on Ceilings for Exposure Temperature Levels

of 350, 400 and 450°C and Clearances of 241 and 456 mm 58

Figure 14. Temperature Rise on Ceilings for Exposure Temperature

Levels of 350, 400 and 450°C and Clearances of 76, 152

and 229 mm 59

-vi-
List of Figures (continued)

Page

Part III

Figure 15. Thermocouple Locations on Exposed Wall and Ceiling 7 9

Figure 16. Appliance Construction Details 80

Figure 17. Test Apparatus - Arrangement for Minimum Clearance Tests .... 81

Figure 18. Relation of Appliance to Protector Plate System and

Thermocouples on Wall Surface 82

Figure 19. Vertical Plane - Temperature Rise on Wall Surface 83

Figure 20. Horizontal Plane - Temperature Rise on Wall Surface 84

Figure 21. Range of Temperature Rise Along the Horizontal Plane

of a Room Wall (Systems Rl - R3) 85

Figure 22. Range of Temperature Rise Along the Horizontal Plane

of a Room Wall (Systems R4 - R7) 86

Figure 23. Range of Temperature Rise Along the Horizontal Plane

of a Room Wall (Systems R8 - Rll) 87

Figure 24. Range of Temperature Rise Along the Horizontal Plane

of a Room Wall (Systems R12 - R14) 88

Figure 25. Range of Temperature Rise Along the Vertical Plane

of a Room Wall (Systems Rl - R5) 89

Figure 26. Range of Temperature Rise Along the Vertical Plane

of a Room Wall (Systems R5 - R9) 90

Figure 27. Range of Temperature Rise Along the Vertical Plane

of a Room Wall (Systems RIO - R13) 91

Figure 28. Range of Temperature Rise Along the Vertical Plane

of a Room Wall (System Rl 4) 92

Figure 29. Ceiling - Temperature Rise on Ceiling Surface 93

Figure 30. Peak Temperature Rise on Room Ceiling Exposed to a Chimney Connector from a Radiant Heating Appliance 94

Figure 31. Clearance Reduction System for Residential Heating

Appliance 95

Figure 32. Clearance Reduction System for Residential Heating

Appliance 96

-vii-
List of Figures (continued)

Page

Figure 33 . Masonry Clearance Reduction System 97

Figure 34. Non-Combustible Spaces for Clearances Systems 98

Figure 35. Air Movement Around Protector Plates or Panels 99

-viii-
ABBREVIATION KEY TO TABLES

Wall Protection Systems

Identification

W

WW

WB

CB

M

MB

Al

A1B

28G

28GB

24G

24GW

24GB

FG

BR

Material

Gyp8 urn wallboard

Gypsum wallboard white

painted surface

Gypsum wallboard black

painted surface

A Air space

AA Air space

C Inorganic Insulation

board "C

M

CC Inorganic Insulation

board "C"

Inorganic Insulation board

"C" painted black

Inorganic Insulation

board "M"

Inorganic Insulation

board "M" painted black

Aluminum metal plate

Aluminum plate black

painted surface exposed

Galvanized metal plate

Galvanized metal black

painted surface exposed

Galvanized metal plate

Galvanized metal white

painted surface

Galvanized metal black

painted surface exposed

Fiberglass

Brick wall

mm

10

10

25

50

6

12

12

0.6

0.6

25

90

Thickness

in

0.375

0.375

1.0

2.0

0.25

0.25

0.25

0.50

0.024

0.015

1.0

3.50

gauge

3 0.125 —

3 0.125 -

0.4 0.015 28

0.4 0.024 28

24

24

-ix-
Abbreviation Key to Tables (continued)

Wall Protection Systems Thickness

Identification Material mm in gauge

BRV Brick veneer 6 0.25

P Wood paneling 18.8 0.75

T Wall mat (plaster type) 25 1.0

S Wall insulation

-x-
CLEARANCES AND METHODS OF PROTECTION FOR WALL AND CEILING

SURFACES EXPOSED TO RADIANT HEATING APPLIANCES

Joseph J. Loftus

Richard D. Peacock

Abstract

The Center for Fire Research In the National Bureau

of Standards has evaluated the fire hazard potential

associated with the Installation and use of solid fuel

burning appliances (and chimney connectors) In residential housing.

For this three-part study, mock-up and full scale

room walls and ceilings were exposed to radiant energy

from chimney connectors and an appliance operated under

normal and overfire conditions at various distances or

clearances from the room members. Peak surface temperature rise measurements were made on exposed and protected

walls and ceilings and comparisons were made with surface

temperature rise limitations established by building and

fire codes.

In the testing program, a total of 19 different

thermal barriers or protection systems were evaluated and

a number were found capable of providing adequate thermal

protection. Particularly effective were those systems

which used a sheet metal plate or two sheet metal plates

with an insulative layer between them mounted in front of
a wall or ceiling and separated from the room surface by

a 25 mm (1 in) air space. This provision for air to

circulate freely between a room member and its protector

proved to be an extremely important factor in providing

for increased fire safety.

Based on these findings, recommendations are made

which building and fire code officials may find useful in

preparing fire safety codes and regulations designed to

protect the consumer from personal and property damage

caused by unwanted fires.

Key words: ceilings; chimneys; fire codes; fire

protection; fire tests; interior finishes; radiant

energy; residential buildings; stoves; walls.

1 . INTRODUCTION

The Consumer Product Safety Commission and the Department of Energy have

sponsored research at the Center for Fire Research in the National Bureau of

Standards to investigate the fire safety of wood burning appliances (stoves)

used for space heating in single family homes and similar residences. The

objective of this work is to reduce the number of house fires that occur every

year in the United States as a result of faulty heating stove and chimney

connector installations.
The testing program described in this report was divided into three

parts:

Part I. Systems for Protection of Wall Surfaces Exposed to

Radiant Appliances.

Part II. Systems for Protected Wall and Ceiling Surfaces

Exposed to Heating Appliance Chimney Connectors.

Part III. Full Room Validation of Wall and Ceiling Devices

for Heating Appliance and Chimney Connector

Systems.

2. BACKGROUND

With the advent of high fuel costs, increasing numbers of consumers have

turned to using alternate fuel sources for home heating; wood, in particular,

is being used in place of traditional gas and oil fuels. The unfortunate part

of this solution, however, is that the number of house fires has shown a

marked increase because many consumers and homeowners are making stove installations (in their homes) that are clearly in violation of building and fire

safety code regulations.

The main problem lies in the fact that wood is a combustible material and

that most homes are made with "stick construction"; that is, wood is used in

framing out the house. Wood has an ignition temperature of about 200 °C

(392°F); however, there have been reports of wood ignition after long term
conditioning to exposure temperatures as low as 60 to 108°C (140 to 226°F)

[1,2] . Wood framing in close proximity to a hot chimney surface is thus

highly susceptible to ignition because chimney surfaces can reach temperatures

as high as 240°C (464°F) due to the fact that flue gas temperatures in lined

chimneys can easily exceed 592°C (1100°F).

On this basis, codes recommend that wood should not be exposed to temperatures higher than 100°C (212°F) and that wood framing around chimneys be

separated from the chimney by an air space of at least 50 mm (2 in) to be

considered safe. Concerning clearances between combustibles and solid fuel

burning appliances (including chimney connectors), the codes recommend that

the radiant heating appliances be located at least 914 mm (36 in) away from

adjacent surfaces and that distances between single wall, metal chimney

connector pipes and combustibles be 457 mm (18 in). The National Fire

Protection Association considers these clearances to be adequate for maximum

appliance surface temperatures ranging from 300 to 350°C (572 to 662°F);

however, for reduced clearances to combustibles, two materials are listed as

suitable for use as thermal barriers or protective devices - asbestoscontaining mill boards (in various thicknesses) and sheet metal. Health

concerns with asbestos, however, strongly suggest against its use.

In previous reports [1-4] submitted to the Department of Energy and to

the Consumer Product Safety Commission on the fire safety of wood-burning

appliances, CFR has presented information on a survey of fire incidents

involving wood-burning appliances and a review of codes and standards dealing

Numbers in brackets refer to literature references listed in section 24 at

the end of this report.
with solid fuel appliances. These reports provided the basis for research on

proper clearances between wall lining surfaces and wood-burning appliances and

on protective devices that may be used to allow for reduced clearances.

The following three part report details the results of such a research

effort designed to study the effects that clearances and protective devices

have on surface temperatures of room walls and ceilings exposed to radiant

energy from hot appliance and chimney connector pipe surfaces.

3. REVIEW OF PREVIOUS WORK

3.1 Minimum Safe Clearance and Temperature Specifications

in Existing Codes and Standards

Recommendations for minimum acceptable clearances to combustible

materials for the installation of chimneys, chimney connectors, and appliances

are specified in the various model codes and recommended practice manuals

[2,5-13]. For simplicity and ease of enforcement, a single (hopefully conservative) clearance is given for each type of appliance Installed without

protection. No allowance is made for the size, heat output, heat transfer

characteristics, or other features unique to individual models. Similarly,

only a few, specific methods of protection employed to allow reduction of

these clearances are recommended. Typically, 914 mm (36 in) of clearance is

specified between radiant heaters and unprotected combustible construction in

the codes. For circulating heaters, clearances of 610 mm (24 in) from the

front of the appliance and 305 mm (12 in) from the sides and back of the

appliance are recommended [13]. For single wall metal chimney connectors,

457 mm (18 in) is usually recommended as a minimum clearance [12].
The experimental basis for these code requirements, however, is not quite

clear. Several experimental studies have been carried out to determine

minimum acceptable clearances to combustible materials. Voigt [14], in a 1933

publication, recommends a minimum clearance of 305 mm (12 in) for chimney

connectors 229 mm (9 in) in diameter. A more extensive study, performed by

Underwriters Laboratories in 1943 [15], presents minimum safe clearances for

both unprotected surfaces and surfaces protected by various methods.

Distances at which a maximum temperature rise of 50°C (90°F) above room

temperature is reached are presented as a function of the temperature of the

exposed face of a heat producing appliance. The relative protection afforded

by various materials used as heat barriers between the appliance and combustible surface was also examined. Lawson, Fox, and Webster [16] and Lawson and

Simms [17] studied the heating of wall panels and wood by radiation. With

experimentation and theoretical predictions, they present safe clearances

between flue pipes and wall surfaces as a function of the pipe diameter and

the pipe surface temperature. To maintain a maximum wall temperature of 100°C

(212°F), a 152 mm (6 in) pipe should not exceed 350°C (662°F) in surface

temperature at a clearance of 456 mm (18 in) [16].

These experimental studies established limits for two important

parameters: appliance surface temperature and clearance to combustibles for

unprotected and protected surfaces. Maximum appliance surface temperature for

the appliances studied ranged from 300 to 350°C (572 to 662°F). Minimum safe

wall clearance for unprotected surfaces range from 805 to 914 mm (12 to

36 in) . Most of the current code provisions are only adequate for maximum

appliance surface temperatures up to 300 to 350°C. In addition, all the

methods of wall protection specified in the model building codes use two
materials: asbestos millboard in various thicknesses and sheet metal. With

the current health concerns with the use of asbestos, few alternatives are

left for wall and floor protection.

3.2 Temperatures Developed in Heating Systems

Tests made with prefabricated porcelain-enameled metal chimneys for solid

or liquid fuel furnaces [18,19] established a limiting temperature rise of

190°C (374°F) on the outer surface of the chimney for a flue gas temperature

of 537°C (1000°F). With this limitation, wood framing spaced 50 mm (2 in) or

more away from the chimney was considered safe. Satisfactory insulation of

the chimneys to reduce the outer surface temperatures to acceptable levels was

obtained with asbestos paper plies totaling about 45 mm (1-3/4 in) in thickness. In the same study, some asbestos-cement pipe coverings were also found

to reduce heat transmission to the extent required for safety of nearby

combustibles.

To establish performance requirements for lightweight prefabricated

chimneys, tests were conducted with lined and unlined masonry chimneys having

102 mm (4 in) thick walls [20]. Hazardous conditions on wood framing spaced

5 mm (2 in) away from the chimney were noted with a continuous flue gas

temperature of 482°C (900 °F) for the unlined chimney and 592 °C (1100°F) for

the lined chimney. However, these hazardous conditions were not reached in

the lined chimney tests until after 13 hours. In order to study operating

conditions with typical fuels, a number of firing tests [21] were conducted

with heating appliances known to give high flue gas temperatures , using wood

and soft coal as fuels. With a coal-fired, jacketed type heater, gas tempera-
tures ranging from 648°C to 704°C (1200°F to 1300°F) were measured for an hour

or more in the flue at the ceiling level above the heater.

Lawson et al [16] present the results of tests to measure surface temperatures of flue pipes to validate theoretical predictions. Measured for a variety of flue systems using solid fuels—mostly coal and coke—they report

temperatures of about 150°C (300°F) under "normal conditions" and temperatures

as high as 815°C (1500°F) under overload conditions.

Fox and Whittaker [21] report temperatures on metal flues of several

heating appliances over a range likely to be encountered in normal use.

Maximum flue pipe surface temperatures ranged from 704 to 815°C (1300 to

1500°F) at the appliance flue outlet, 360 to 510°C (680 to 950°F) at a

distance of 0.91 m (3 ft) from the appliance flue outlet and 287 to 326°C (550

to 620°F) at a distance of 1.83 m (6 ft) from the appliance flue outlet.

Shoub [18] concludes that combustible materials will be ignited if

maintained in continued contact with a masonry chimney of 120 mm (4-3/4 in)

wall thickness and with flue gas temperatures of 398°C (750°F).

Current Underwriters Laboratories test procedures for prefabricated

chimneys require testing of chimney assemblies with hot flue gases [22]. Fiue

gas temperatures of 537 °C (1000°F) are maintained until steady-state conditions are reached, followed by 759°C (1400°F) for 1 hour and 928°C (1700°F)

for 10 minutes. These conditions are intended to simulate worst-case

conditions.
In tests for the Department of Energy [2], temperatures ranging from 297

to 436°C (567 to 817°F) during normal operation and 377 to 693°C (712 to

128 1°F) during overload conditions were noted on the surfaces of late model,

wood-burning appliance surfaces.

In the present study, peak appliance surface temperatures are employed.

3.3 Limiting Safe Temperatures on Combustible Surfaces

Listings of heat producing appliances and methods for setting clearances

between appliances and combustible surfaces are based on Underwriters

Laboratories listings:

• maximum temperature rise of 65 °C (117°F) above room

temperature on exposed surfaces; and,

• maximum temperature rise of 50 °C (90 °F) above room

temperature on unexposed surfaces such as beneath the

appliance, floor protector, or wall-mounted shield [24].

These requirements are based on the fact that, while the ignition temperature of wood products is generally quoted to be on the order of 200°C (392°F)

[12], wood that is exposed to constant heating over a period of time may

undergo a chemical change resulting in a much lowered ignition temperature and

increased potential for self-ignition. Results of some of the research

describing this phenomenon are enumerated below.
Mitchell [25] presents data on wood fiberboard exposed to temperatures as

low as 109 °C (228°F) that resulted in ignition after prolonged exposure.

MacLean [26,27] reports charring of wood samples at temperatures as low as

93°C (200°F). He concludes that wood should not be exposed to temperatures

appreciably higher than 66°C (150°F) for long periods. McGuire [28] suggests

that the maximum safe temperature on the surface of a combustible material

adjacent to a constant heat source should be no more than 100 °C (212°F).

Clearly, the ignition of wood at moderately elevated temperatures is a

complex phenomenon; the time of exposure is indeed an important parameter [29,

30]. While exact limits recommended in the literature vary due to exposure

time and details of the tests conducted, the numerous documented fires

involving the ignition of wood members near low pressure steam pipes [31]

suggest an upper temperature limit for wood exposed to long-term low-level

heating should not be appreciably higher than 100°C (212°F).

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11
A. WALL PROTECTION SYSTEMS

Table 1 presents sketches of the four unprotected walls and the 19

different wall protection systems evaluated in this study. The systems were especially designed to obtain as wide a spectrum of information as possible on

temperature protection devices for walls exposed to radiant heat from home

heating appliances. As shown, gypsum wallboard served as the base material

for each of the systems. This particular wallboard was chosen because of its

widely accepted use in room wall construction found in homes and other

dwelling places. For 12 of the 23 systems, the wallboard surfaces were

painted black to represent worst case conditions of dirt accumulation or paint

choice. In 11 of the systems, protector surfaces were also painted black.

The exposed surface of each wall system measured 1.2 x 1.2 m (4 x 4 ft)

and the panels were mounted vertically with an allowance made for a 25 mm

(1 in) airspace from the floor.

For the purposes of brevity, a key on the page following table 1

identifies the various components used for the wall protection systems shown

in table 1 and in system descriptions throughout this report. The following

outlines the rationale used in the selection of the particular wall systems

for this evaluation study.

1. Compare surface temperature rise on unprotected and unpainted base

gypsum wallboards "W" (no. 2 and no. 7) with unprotected and black

painted "WB" wallboards (no. 11 and no. 16).

12
2. Determine the protection afforded to the base wallboard material by

metal plate/air space(s) combinations: no. 1 (W,A,A1), no. 6

(W,A,28G), and no. 9 (W,AA,28G).

3. Determine the effect of black painted metal plate(s) and air space(s)

combinations on unpainted wallboard surface temperatures: no. 8

(W,A, 28GB) and no. 10 (W, A, 28GB,A, 28GB)

.

4. Determine the effect of black painted metal plate(s) and air space(s)

combinations on wallboard surface temperatures: no. 12 (WB,A,24GB),

no. 13 (WB,AA,24GB), no. 14 (WB, A, 24GB,A, 24GB) , and no. 15

(WB,A,A1B).

5. Determine the effect of protection systems (attached directly to base

wallboards) on wallboard surface temperatures: no. 3 (W,M), no. 5

(W,M,28G), no. 17 (WB,FG,CB), and no. 22 (WB,BRV).

6. Determine the effect of unpainted insulation boards and a brick wall

offset by air space from the base wallboard on wallboard surface

temperatures: no. 4 (W,A,M), no. 18 (WB,A,CB), and no. 23 (WB,A,BR).

7. Determine the protection offered to black painted wallboards by black

painted metal plate sandwich panels separated by air space from the

wallboard (exposed side of sandwich blackened), no. 19 (WB,A,24GB,

FG,24GB), no. 20 (WB, A, 24GB, C, 24GB), and no. 21 (WB,A,24GB,CC,24GB)

.

13
Since "worst-case conditions" were created by black painted surfaces, it

was expected that the effectiveness of the different wall protection systems

might be judged by their ability to reflect or absorb radiation and/or to

dissipate absorbed radiation. For insulating materials, the following

properties were noted:

Thermal Properties of Insulating Materials Used in Wall Protection Systems

Density

(kg/m3

) Thermal Conductivity

Component Material (W/mK)

M Calcium Silicate Board 769 0.14

CB Refractory Fiber Board 384 0.13

FG Fiberglass 60 0.037

BR Brick 2600 0.8

BRV Brick Veneer 2600 0.8

5. TEST APPARATUS

A mock-up heating stove apparatus was constructed for the test series.

The stove enclosure was fabricated with 6 mm (1/4 in) thick steel plates and

measured 500 x 500 x 500 mm (20 x 20 x 20 in). The fire box was supported

350 mm (14 in) from the floor by steel angles attached to the box. The test

apparatus, illustrated in figure 1, has a radiant panel mounted on the floor

of the stove enclosure. The panel consists of a porous refractory material

mounted in a cast-iron frame allowing for the combustion of gas over its

surface which measures 304 x 457 mm (12 x 18 in). Natural gas mixed with air

was used for the tests. Venting for the stove was provided by a conventional

152 mm (6 in) diameter stovepipe system.

14
Figure 2 shows the location of five 24-gauge, 0.5 mm (0.020 in) chromelalumel thermocouples attached to the irradiating surface of the stove facing

the test walls. One thermocouple was located at the center of the

500 x 500 mm (20 x 20 in) surface, and the four remaining thermocouples were

positioned at 152 mm (6 in) distances from the center thermocouple in both the

horizontal and vertical planes. The thermocouples were attached to the steel

plate by metal washers fastened to the plate with sheet metal screws.

Figure 3 shows the thermocouple system (24 gauge chromel-alumel) , used to

monitor the temperatures generated on the irradiated and protected wallboard

surfaces of the wall systems during tests. One thermocouple was mounted at

the center of each test panel (measuring 1.2 x 1.2 m) and from this thermocouple additional thermocouples were positioned in horizontal and vertical

lines at distances of 152, 304, and 457 mm (6, 12, and 18 in) from the center.

For temperature averaging purposes, equidistant thermocouples were connected

in parallel. Ambient air temperature in the test room was measured by a

thermocouple shielded in a 152 mm (6 in) aluminum pipe located 1.2 m (4 ft)

from the stove.

6. TEST PROCEDURES

Wall test panels were mounted in a vertical position and stove to wall

clearances were adjusted over the following six distances: 914, 610, 457,

304, and 76 mm (36, 24, 18, 12, and 3 in). (Note: the clearance established

by Fire Codes [8], i.e., 914 mm (36 in), was used as the starting point for

tests.) With the center thermocouples on the stove and wall panel surfaces in

alignment, the stove's gas radiant panel was fired. Gas flows to the panel

15
were monitored over a range of 14 to 76 lis (30 to 160 SCFM) to provide the

desired test temperature levels on the stove surface; i.e., 150, 200, 250,

300, and 350°C. The range of these temperatures is based on previous work

with actual wood-burning appliances [2]. Functions describing the relation

between wall surface temperature and distance are derivable from theory and

these are discussed in detail in reference [23].

Stove surface temperatures were quickly and easily maintained; however,

the irradiated wall test surfaces did not reach a reasonable level of

constancy until 2 to 3 hours of exposure time had passed. Typically, a test

was started with the test wall 914 mm (36 in) away from the radiating stove

surface. When the temperature on the wall reached peak value, that temperature was recorded for the test location. The wall was then moved to the next

closer test location and the testing procedures were repeated exactly. The

peak temperature rise values for each test location and stove temperature were

used for data analysis and plotting.

The time required for obtaining a complete set of data for the temperature and clearance tests was approximately 1 to 1-1/2 working days.

7. TEST RESULTS AND DISCUSSION

Figures 4 to 8 show the temperature rise (peak surface temperature minus

room temperature) obtained for tests on each of the 23 gypsum wallboard

surfaces (unprotected and protected) at six different clearances between the

wall and stove surface, i.e., 914, 760, 610, 457, 304, and 76 mm (36, 30, 24,

18, 12, and 3 in) and five different stove temperatures, 150, 200, 250, 300,

16
and 350°C (270, 392, 482, 572, and 662 F). As expected, the smallest temperature rise values were obtained for the 914 mm (36 in) clearances and the

highest for the 76 mm (3 in) separations.

For discussion and comparison purposes, attention will be focused on the

peak temperature rise data listed in table 2 for worst case conditions: 350°C

stove surface temperature and 76 mm (3 in) stove-wall clearance. An analysis

of the test results showed the following.

7.1 Unprotected Gypsum Wallboard - Painted Versus Unpainted Surfaces

Peak Wallboard

Temperature Rise, °C

No. 2 (W) Unpainted Wallboard 68*

No. 7 (W) Unpainted Wallboard

** Ignition

No. 11 (WB) Black painted

wallboard

Ignition

No. 16 (WB) Black painted

wallboard

•r ., ., ** Ignition

*250°C (482°F) test @ 304 mm (12 in) - not tested @ 350°C (662°F)

**Because of ignitions, these samples are not listed in table 2.

For worst case exposures, the paper surface (painted and unpainted) of

the gypsum wallboard ignited and flamed for 3 to 12 minutes. Surface damage

amounted to an approximate 304 mm (12 in) diameter circle of paper being

burned away before extinguishment occurred. Tests at the 304 mm (12 in)

clearance showed that the effect of the black painted surface on temperature

rise was not in evidence.

17
7.2 Effect of Metal Protector and Air Space on Wallboard Surface Temperature

Peak temperature rise data for wallboard surfaces protected by air

space(s) and unpainted metal plates are listed below:

Temperature Rise, °C

No. 1 (W,A,A1) -2*

No. 6 (W,A,28G) 1

No. 9 (W,AA,28G)

*300°C (572°F) test - not tested at 350°C (662°F). Negative

rise indicates a lower surface temperature on protected board

than recorded for ambient room conditions.

Results of these tests show that no appreciable surface temperature rise

was recorded for the air space and metal plate protected wallboard surfaces.

7.3 Effect of Black Painted Metal Protector and Air Space

on Wallboard Surface Temperature

Two systems were tested using a black painted metal protector in front of

an unpainted wallboard:

Temperature Rise, °C

No. 8 (W,A,28GB) 80

No. 10 (W, A, 28GB, A, 28GB)

18
The contribution of a black painted metal protector plate to unpainted

wallboard surface temperature rise is shown in these tests where the plate

surface in system no. 8 registered 230°C (446°F) and the protected wallboard

developed a temperature rise of 80°C (176°F). By comparison, an unpainted

protector plate in system no. 6 (Section 7.2) showed a surface temperature of

107 °C while its protected wallboard showed temperatures at the room temperature level.

System no. 10 clearly showed the advantage of using an additional air

space and metal plate protector for wallboard thermal protection. For no. 10

the temperature rise on the wallboard surface was negligible while no. 8

(which had a single air space and metal plate) allowed an 80°C (176°F)

temperature rise. In both cases the protector plate surfaces were painted

black.

7.4 Effect of Black Painted Metal Protectors and Air Space

on Black Painted Wallboard

Four systems tested consisted of black painted metal protectors with a

black painted wallboard surface:

Temperature Rise, (°C)

No. 12 (WB,A,24GB) 112

No. 13 (WB,AA,24GB) 52

No. 14 (WB,A, 24GB, A, 24GB)

No. 15 (WB,A,A1B) 181

19
For these tests, a thicker metal plate [24 gauge (0.024 in.)] was used

for wallboard protection. A comparison of results for system no. 14 (24

gauge) with system no. 10 (28 gauge) (Section 7.3) however showed no temperature rise on the wallboard surfaces, and the board in no. 14 was painted

black.

For system no. 15, the protector was an 8 gauge (0.128 in) aluminum metal

plate painted black. This plate developed a surface temperature of 263°C

(505°F) and the black painted wallboard separated from the plate by an air

space showed a surface temperature rise of 181°C (357°F). In this case, the

metal plate thickness did appear to contribute significantly to wallboard

temperature rise.

The advantage of using an additional 25 mm (1 in) air space between the

wallboard and protector plate was demonstrated by tests on system no. 13 where

the wallboard showed a temperature rise of 52°C (125°F). By comparison, the

wallboard in system no. 12 protected by a single air space and metal plate

showed a temperature rise of 112°C (234°F), or 60°C (140°F) higher than the

board in no. 13.

The effects of black surfaces on wallboard surface temperature rise were

exhibited by the comparison of results for system no. 12 with those obtained

for system no. 8 (Section 7.3). The wallboard in no. 8 had an unpainted

surface and was protected by a black painted 28 gauge plate. Its temperature

rise was 80°C. The wallboard in system no. 12 was painted black and its 24

gauge protector plate was painted black. Its temperature rise was 112°C

(234°F). Here the higher temperature rise can be attributed to the

20
combination of a black painted board surface and a black painted and thicker

metal plate protector.

7.5 Effect of Protective Devices Attached Directly to Wallboard

Results of tests on four different wall systems are listed as follows:

Temperature Rise, °C

No. 3 (W,M) 136*

No. 5 (W,M,28G) 6

No. 17 (WB,FG,CB) 99

No. 22 (WB.BRV) 292

*300°C(572°F) test - not tested at 350°C (662°F)

The value of a metal plate-insulation board combination attached to the

wallboard in system no. 5 was evidenced by the low temperature rise (6°C)

observed for the wallboard. The ability of the unpainted metal surface to

reflect heat combined with the insulation qualities of the insulation board

helped produce the low temperature value. System no. 3 used the same insulation board but did not have the benefit of a metal cover plate and thus the

protected wallboard surface temperature rise reached 136°C (277 °F) even at an

exposure temperature of 300°C (572°F). System no. 17 used a fiberglass and

"C type" insulation board package to protect a painted wallboard. The

wallboard material developed a temperature rise of 99°C (210°F).

In tests on system no. 22, the 6 mm (1/4 inch) thick brick veneer

attached to the wallboard developed a glow on its surface and caused the paper

21
7.6 Effect of Air Space Combined with Protective Insulating

Boards and a Brick Wall on Wallboard

Results of tests on three different wall systems are listed as follows

Temperature Rise, °C

No. 4 (W,A,M) 30*

No. 18 (WB,A,CB) 67

No. 23 (WB,A,BR) 57

*300°C (572°F) test - not tested at 350°C (662°F)

The advantage of using an air space for helping to reduce wallboard

surface temperatures was again illustrated by a comparison of system no. 4.

with system no. 3 (Section 7.5). With the air space In no. 4, the wallboard

showed a temperature rise of 30°C. However, in no. 3 where no air space was

used the wallboard developed a temperature rise of 136°C (277°F) for exposures

at 300°C (572°F). System no. 18 used a black painted "C type" insulation

board and air space to protect a black painted wallboard. Here the wallboard

showed a temperature rise of 67°C (153°F).

The solid brick wall in system no. 23 registered a peak surface temperature of 342°C (684 F) and the painted wallboard separated from the wall by

25 mm (1 in) air space showed a temperature rise of 57°C (135°F).

22
7.7 Effect of Black Painted Metal Sandwich Panels and Air

Space on Wallboard Surface Temperature

Results from tests on three different wall systems are listed as follows

Temperature Rise, °C

No. 19 (WB,A,24GB,FG,24GB) 7

No. 20 (WB,A,24GB,C,24GB) 11

No. 21 (WB,A,24GB,CC,24GB) 10

Each of the sandwich panels was successful in maintaining low temperature

rise on the protected wallboard surfaces. Results indicate negligible differences between the different sandwich fill materials and their effect on wallboard temperatures.

8. SUMMARY OF RESULTS

A total of 23 different wall systems (19 protected and 4 unprotected)

were evaluated for their ability to resist radiant energy exposure from a

simulated wood fired stove operated at five different temperature levels

ranging from 150 to 350°C (302 to 662°F). Clearances between the walls and

the stove were varied from 76 to 914 mm (3 to 36 in).

Figures 4 to 8 show temperature rise on the base gypsum wallboard

surfaces as determined for each of the exposure tests at the various

clearances

23
Table 2 lists the wall system number, peak temperatures for the protector

and wallboard surfaces, the test room temperature, and the temperature rise

for the protector and wallboard surfaces above room temperature. Except where

noted, all of these values are for "the worst-case" conditions of 350°C

(662°F) stove surface temperature and stove to wall surface clearances of

76 mm (3 in).

The unprotected and unpainted gypsum wallboard systems, no. 2 and 7, and

black painted unprotected gypsum wallboards, 11 and 16, are not listed. This

is because the paper surfaces on each of the boards ignited and burned away

during tests at the 300°C (572°F) exposure.

The criteria used for evaluation of data listed in table 2 were based on

recommendations made by Underwriters Laboratories [24] that the upper limit

for temperature rise above room temperature on unexposed surfaces, such as

beneath an appliance, floor protector, or wall mounted shield, be 50°C (90°F).

They also cite a temperature limit of 65°C (117°F) on exposed combustible

surfaces, but this limit was not considered applicable to the protector

surface data also listed in table 2 since the protectors were made of

noncombustible materials.

9. OBSERVATIONS

Based on an analysis of the data listed in table 2 the following

observations are made.

24
1. A total of 8 systems were successful in limiting wallboard surface

temperature rise to less than 50°C for tests under worst-case conditions. (Missing from this listing is system no. 1 (W,A,A&) which was

only tested at the 300°C exposure and showed a negligible surface

temperature rise. If tested at 350°C this system would clearly have

passed the test exposure.)

Temperature Rise, °C

No. 5 (W,M,28G) 6

No. 6 (W,A,28G) 1

No. 9 (W,A,A,28G) 3

No. 10 (W,A, 28GB,A, 28GB)

No. 14 (WB, A, 24GB, A, 24GB)

No. 19 (WB,A,24GB,FG,24GB) 7

No. 20 (WB,A, 24GB, C, 224GB) 11

No. 21 (WB,A,24GB,C,C,24GB) 10

2. Except for system no. 5 all of the systems used air space(s) between

the wallboard and protectors.

3. Systems with two air spaces and protector plates provided the greatest

thermal protection for the wallboard.

4. Systems with sandwich panels as protectors showed temperature rise

values ranging from 7 to 10°C (13 to 18°F).

25
5. Systems failing to meet the 50°C temperature rise limitation were:

Temperature Rise, °C

No. 8 (W,A, 28GB) 80

No. 12 (WB,A,24GB) 112

No. 13 (WB,AA,24GB) 52

No. 15 (WB,A,A1B) 181

No. 17 (WB,FG,CB) 99

No. 18 (WB,A,CB) 67

No. 22 (WB,BRV) 292

No. 23 (WB,A,BR) 57

Systems allowing the wallboard surface temperature to rise above 100°C

(212°F) were nos. 12, 15 and 22. In no. 22 the simulated brick veneer

sample actually developed smoldering. In no. 15 the 8 gauge aluminum

plate painted black developed a temperature of 263°C (505 °F).

6. Both unpainted and painted gypsum wallboard surfaces in systems

nos. 2, 7, 11, and 16 respectively, ignited when the unprotected

surfaces were tested at 350°C (662°F) exposures. Damage, however, was

limited to the exposure area.

7. Three systems nos. 1 (W,A,A1), 3 (W,M), and 4 (W,A,M) were not tested

at 350°C.

26
on the wallboard also to ignite and glow and thus a peak temperature of 292°C

(558°F) was observed.

8. Figure 9 summarizes the clearance test results for 15 of the wall

systems. An examination of this figure shows that seven systems

provided acceptable wallboard surface temperature rise for clearance

reductions to 76 mm (3 in) between the stove and wall surfaces. Six

systems needed 304 mm (12 in) clearance to provide for code acceptable

performance. One system needed (no. 17) (WB,FG,CB) 457 mm (18 in)

clearance and system (no. 22) (WB,BRV) failed tests even when the

clearance was 914 mm (36 in).

10. CONCLUSIONS

1. Room walls in proximity to home heating appliances need thermal protection

from irradiating hot stove surfaces.

2. The most efficient wall protection systems found in these tests were those

which used an air space 25 to 51 mm (1 to 2 in) in combination with

unpainted metal plate protectors or an air space combined with sandwich

panels consisting of a noncombustible board or fiberglass material between

two metal plates. Such systems allowed for clearance reductions to as low

as 76 mm (3 in) between walls and stove surfaces at 350°C (662 F).

3. The wall protection systems using a single metal plate and air space were

found to require 304 mm (12 in) clearances from the stove when their

exposed surfaces were painted black.

27
4. Wall systems using 2 air spaces in combination with 2 metal plates permit

clearance reductions to 76 mm (3 in) at the 350°C (662 F) exposure even

when the metal plate surfaces and wallboard are painted black.

5. A brick wall required 304 mm (12 in) clearance from a stove when the

separation between the brick wall and the protected wall was a 25 mm

(1 in) air space.

6. Thin masonry veneer attached directly to a combustible wall affords little

thermal protection to the wallboard material.

28
Table 1. Twenty- three Wall Protection Systems Tested

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KEY to Table 1

Wall Protection Systems

Identification Material

W

WB

A

AA

C

CC

CB

M

Al

A1B

28G

28GB

24G

24GB

FG

BR

BRV

Gypsum wallboard

Gypsum wallboard black

painted surface exposed

Air space

Air space

Inorganic Insulation

board "C"

Inorganic insulation

board "C"

Inorganic insulation board

"C" painted black

Inorganic insulation

board "M"

Aluminum metal plate

Aluminum plate black

painted surface exposed

Galvanized metal plate

Galvanized metal black

painted surface exposed

Galvanized metal plate

Galvanized metal black

painted surface exposed

Fiberglass

Brick wall

Brick veneer

Thickness

mm In

10 0.375

10 0.375

25 1.0

50 2.0

6 0.25

gauge

12 0.50

6 0.25 —

12 0.50 -

3 0.125 -

3 0.125 -

0.4 0.015 28

0.4 0.024 28

0.6 0.024 24

0.6 0.015 24

25 1.0 -

90 3.50 -

6 0.25 —

30
Table 2. Temperature Rise Above Room Temperature for Protector and Gypsum

Wallboard Surfaces for "Worst-Case" Conditions*

Wall System

No.

Peak Temperature°C

Protector Wallboard

55 A3

Temperature °C

Test Room

Temperature

Protector

18

Rise °C

Wallboard

5 37 6

6 107 37 36 71 1

8 230 120 40 190 80

9 158 38 35 123 3

10 305 38 38 267

12 333 152 40 293 112

13 317 86 34 283 52

14 305 35 35 270

15 263 214 33 230 181

17 360 129 30 330 99

18 300 100 33 267 67

19 359 34 27 332 7

20 360 40 29 331 11

21 367 39 29 338 10

22 375 328 36 339 292

23 342 89 32 310 57

1 ** 96 37 39 57 -2

3 ** 203 174 38 165 136

4 ** 207 72 33 174 39

Worst case conditions stove surface 350°C (662°F), stove-wall clearance 7.5 cm

..(3 in).

Stove surface 300°C (572°F)

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41
11. TEST APPARATUS FOR CHIMNEY CONNECTOR TESTS

The test apparatus used for the Part II testing program consisted of the

same stove apparatus as used in Part I (see Figure 1) plus a chimney connector

pipe venting system. The connector pipe was conventional steel, single wall,

0.46 mm (0.018 in) thick and had a diameter measuring 152 mm (6 in).

Figure 10 shows a sketch of the stove and the location of vertical and

horizontal chimney connector pipes in relation to the wall and ceiling panels.

The vertical pipe measured 1.6 m (64 in) in length and had five 24 gauge

(chromel-alumel) thermocouples attached to its outer surface in a vertical

line central to the pipe. The first (or bottom) thermocouple was located

914 mm (36 in) from the floor and the other thermocouples were spaced 200 mm

(8 in) apart. The thermocouples were attached to the steel pipe by metal

washers fastened to the pipe with sheet metal screws. Attachments were made

on the side of the pipe away from the wall for ease of maintenance.

Figure 11 shows a room wall section with 30 thermocouples attached to its

front surface. Using thermocouple attachment procedures outlined in section

9.11 of UL 1482 "Room Heaters, Solid Fuel Type" the thermocouples were secured

to the surface by staples placed over the insulated portion of the wires. The

thermocouple tips were depressed flush to the wall surface at the point of

measurement and held in thermal contact with the surface at that point by

pressure sensitive electrical tape. The thermocouples, arranged 10 to a row,

were spaced 152 mm (6 in) apart in vertical lines with the first or bottom

thermocouple in each of the three rows located 914 mm (36 in) from the floor.

Each row of thermocouples was connected in parallel, thus average temperatures

were obtained.

42
Figure 12 shows a ceiling section with 9 thermocouples attached to the

exposed (unprotected or protected) surfaces. Attachments were made in the

same manner as described above. Spacing between thermocouples was 152 mm

(6 in). This thermocouple string was connected in parallel also to obtain

average temperatures.

12. TESTING PROGRAM

12.1 Test Systems

For the purposes of brevity, a key following table 3 identifies abbreviations for the various components used in the construction of the wall and

ceiling systems. As indicated, gypsum wallboard served as the base material

for each of the panels. This 16 mm (5/8 in) thick material was chosen because

of its widely accepted use in room wall and ceiling construction found in

dwellings. For a number of systems, the wallboard surfaces were painted black

so that the effectiveness of different wall and ceiling protectors might be

judged by their ability to reflect or absorb radiation and/or dissipate

absorbed radiation.

The overall dimensions of the wall panels and their protective shields

measured 1.2 x 2.4 m ((4 x 8 ft) and ceiling panels and shields measured

1.2 x 1.2 m (4 x 4 ft). The protector plate used for the ceiling panels was

0.61 mm thick (24 gauge) and was offset from the ceiling panel by a 25 mm

(1 in) air space. In nine of the systems, the leading edge of the ceiling

protector plate was located 25 mm (1 in) away from the vertical wall protector

plate. This arrangement allowed for air circulation around the ceiling

protector plate.

43
For three other systems, no separation existed between the wall and

ceiling protector plates because the leading edge of the celling plate

contacted or intersected the wall plate. (See systems 48, 49, and 50 in table

3). This arrangement permitted a study of the effect that "no air movement"

between the wall and ceiling might have on surface temperatures of the

protected wall and ceiling panels.

Table 3 details clearances between the wall and ceiling panels and the

chimney connector pipe. For example:

• Clearances to ceilings ranged from 76 to 457 mm (3 to 18 in).

• Clearances to walls remained at 76 mm (3 in) for all tests.

Chimney connector exposure temperatures were 350, 400, and 450°C (662, 752,

and 842°F).

12.2 Test Criteria

U.L. Standard for Room Heaters, Solid Fuel Type was used as the source of

the test criteria [24]:

1. A surface temperature rise of 50°C (90°F) above room temperature is

allowed for protected surfaces.

2. A surface temperature rise of 65°C (117°F) above room temperature is

allowed for unprotected surfaces.

44
13. TEST RESULTS

Ceiling and wall panels were exposed to radiant energy from the chimney

connector pipe until peak temperatures were recorded on their surfaces. Table

4 lists the clearances to wall and ceiling and the surface temperature rise

(peak minus room temperature) for tests on each if the systems at the three

different exposure temperature levels. Application of the test criteria to

these data provided the pass-fail results listed in the following table.

13.1 Unprotected Celling Panel Tests

Clearance

(mm/ in) System Wall Ceiling

Connectoi

@350°C

Surface

<§400°C

Temperature

@450°C

241/9.5 No. 25 WB, A, 24GB WB P Fc Fwc

241/9.5 No. 28 WB, A, 24GB, CC, 24GB WB P P Fc

241/9.5 No. 29 WB, A, 24GB, C, 24GB WB P P Fc

460/18 No. 30 WB, A, 24GB, C, 24GB WB P P P

460/18 No. 31 WB, A, T WB P P P

460/18 No. 37 w, P, A, 24G WB P P P

460/18 No. 38 w, P, A, 24GB WB P P Fw

Note: P Pass, Fw Fail wall only, Fc Fail ceiling only, Fwc - Fail wall and

ceiling

Results for the 241 mm (9.5 in) clearance tests show that the black

painted unprotected ceilings and all wall panels passed 350°C (662°F) exposure

tests. One ceiling failure was recorded for the 400°C (752°F) exposure - no.

25 (72°C). All ceilings and one wall failed the 450°C (840°F) exposure

45
tests - no. 25 (83°C H81°Pl on ceiling and 51°C [124 °Fl on wall), no. 28

(71°C-160°F) and no. 24 (73 - C-163°F).

Results for 457 mm (18 in) clearance tests show that the ceiling panels

passed all three exposure temperature tests and that one wall system failed

the 450°C test - no. 38 (55°C).

13.2 Protected Ceiling Panels - with air circulation around the

black painted ceiling protector plate

Clearance

(mm/in) System Wall Ceiling

Connector

<?350°C

Surface

@400°C

Temperature

@450°C

76/3 No. 39 WB, P, A, 24GB WW, A, 24GB P P Fwc

152/6 No. 40 WB, P, A, 24GB WW, A, 24GB P P P

229/9 No. 41 WB, P, A, 24GB WW, A, 24GB P P P

Note: P Pass, Fwc * Fail wall and ceiling

As indicated above, the only failing test results were recorded for 76 mm

(3 in)/450°C (842°F) exposure test of no. 39 where the protected wall surface

reached 52°C and the protected ceiling panel 57 °C.

13.3 Protected Ceiling Panels - with air circulation around an unpainted c«siling protector plat:e

Clearance

(mm/ in) System Wall Ceiling

Connector

@350°C

Surface

@400 °C

Temperature

(§450 °C

229/9 No. 42 WB, P, A, 24GB WW, A, 24G P P P

152/6 No. 43 WB, P, A, 24GB WW, A, 24G P P P

76/3 No. 44 WB, P, A, 24GB WW, A, 24G P P P

Note: Pass

46
The only difference between the celling/wall systems listed above and the

systems described in section 13.2 above was a coat of black paint on the

celling protector plate. As indicated, the unpalnted ceiling systems passed

all clearance/exposure tests at all levels.

13.4 Protected Ceiling Panels - with air circulation around a white painted ceiling protector plate

Clearance

(mm/ in) System Wall Ceiling

Connector Surface Temperature

@350°C @400°C @450°C

229/9

152/6

76/3

No. 45 WB, P, A, 24GB WW, A, 24GW

No. 46 WB, P, A, 24GB WW, A, 24GW

No. 47 WB, P, A, 24GB WW, A, 24GW

P P P

P P P

P P Fc

Note: P - Pass, Fc - Fail ceiling only

The only difference between the above ceiling/wall system and those

discussed in sections 13.2 and 13.3 was a coat of white paint on the celling

protector plate. A celling failure was recorded for no. 47 (55 °C) at the

76 mm (3 ln)/450°C (842 °F) exposure.

13.5 Protected Ceiling Panels - with jio_ air circulation around the

white painted ceiling protector plate

Clearance

(mm/ in) System Wall Ceiling

Connector

@350°C

Surface

0400 °C

Temperature

@450°C

229/9 No. 48 WB, P, A, 24GB WW, A, 24GW P P Fw

152/6 No. 49 WB, P, A, 24GB WW, A, 24GW P P Fwc

76/3 No. 50 WB, P, A, 24GB WW, A, 24GW P Fc Fwc

Note: P - Pass, Fw - Fail wall only, Fc

ceiling

Fail ceiling only, Fwc Fail wall and

47
The only difference between these systems and those described in section

13.3 is that the air gap separating the ceiling and vertical protector plates

was eliminated. Lack of a means for air circulation around the ceiling

protector plate showed that system no. 50 produced a ceiling failure (54°C129°F) at 76 mm (3 in) clearance and 400°C (752°F) exposure and for the wall

and ceiling (51 and 64°C, [124 and 147°F] respectively) at the 450°C (842°F)

exposure. The wall in system no. 48 also failed at 450°C-842°F (51°C-124°F)

as did the system no. 49 wall (53°C) and ceiling (53°C-127°F)

.

14. SUMMARY OF RESULTS

Figures 13 and 14 show plots of all the surface temperature rise data

listed in table 4 for each exposure temperature and clearance test on celling

panels. As expected, the highest values were recorded for unprotected

ceilings and for panels closest to the chimney connector pipes.

A summation of the numbers of failures observed for each of the five test

grouping shows the following:

Number of Failures During Chimney Connector/Wall Protection Tests

Wall Protection System Type

Stove Temperature

350°C 400°C 450°C

Wall Ceiling Wall Ceiling Wall Ceiling

I. Unprotected Ceiling @241 mm

Unprotected Ceiling @457 mm

II. Black Plate - Air Cir.

III. Unpainted Plate - Air Cir.

IV. White Plate - Air Cir.

V. White Plate - No Air

1 l a

3

l a

l al a

l a

l a3 b2 c

?ota1 Failures: Wall 6 Ceiling 9

Note: a - 76 mm failures b 76, 152, 229 mm failures c 76 and 152 mm failures

48
15. TEST OBSERVATIONS

Based on an analysis of test results, the following observations are

aade:

(1) The NFPA code recommends 457 mm (18 in) clearance between single wall

metal chimney connector pipes and ceilings. The results of CFR tests

on unprotected (black painted) ceiling panels support this recommendation. Panels were exposed to three different temperature levels -

350, 400, and 450°C (662,752, and 842°F).

(2) At a clearance reduced to 241 mm (9.5 in), unprotected ceiling panels

met code requirements for 350°C (normal operating temperature) exposure, but failures were recorded for the panels when subjected to

overfire exposures of 400 and 450°C (752-842°F).

(3) Protected ceilings - Ceilings protected by an unpainted metal plate

(plus air space) system passed all exposure temperature tests at

76 mm (3 in) clearances.

(4) Protected ceilings - Ceilings protected by white painted and black

painted metal plate (plus air space) systems showed that clearances

could be reduced to 76 mm (3 in) for 350 and 400°C (662 and 752°F)

exposures, but only to 152 mm (6 in) for 450°C (842°F).

49
(5) The effect of no air circulation around the ceiling protector plate on surface temperature rise of celling and protected wall panels was clearly demonstrated in comparison tests of a protected ceiling

panel/wall system - (protector white painted metal plate plus air

space). For all exposure tests, the air circulating system showed a

single failure (76 mm-3 in/450°C-752°F); however, for "no air" tests,

the total was six failures, one at 76 mm (3 in)/400°C (752°F), and

five at the 450°C (842°F) exposure - walls at 76, 152, and 229 mm (3,

6 and 9 in) clearance and ceilings at 76 and 152 mm (3 and 6 in)

clearance.

(6) Protected walls gave satisfactory results for 76 mm (3 in) clearances

to vertical chimney connector pipes for 350 and 400°C (662 and 752°F)

exposures; however, the walls showed failures at the 450°C (842°F)

exposure.

16 . CONCLUSIONS

The following conclusions apply to those testing conditions when a 152 mm

(6 in) diameter single wall metal pipe connector was used to expose protected

walls and protected and unprotected ceilings to temperatures of 350, 400, and

450°C (662, 752, and 842°F).

(1) Clearances between horizontal chimney connector pipes and unprotected

ceiling panels should be 457 mm (18 in).

50
(2) Clearances between protected celling panels and chimney connector

pipes should be at least 152 mm (6 in).

(3) Clearances between vertical chimney connector pipes and protected

walls should be at least 152 mm (6 in).

(4) If protected walls are combined with no air circulation protected

ceiling systems, the clearance to the vertical pipe should be 304 mm

(12 in) or greater.

(5) If protected ceiling panels have no provision for air circulation the

clearance to the connector pipe should be 304 mm (12 in) or greater.

(6) Although an unpainted metal protector plate system exhibited acceptable clearance reductions to 76 mm (3 in) between ceilings and

chimney connector pipes, protector systems painted white or black

were not acceptable at all clearances. It, therefore, appears desirable that a minimum 152 mm (6 in) clearance be used for all ceiling

metal plate protectors with air space.

51
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KEY to Table 3

Components Used For Hall and Celling Systems

Identification Material

Thickness

(mm) (in)

10 0.38

10 0.38

10 0.38

25 1.00

6 0.25

12 0.50

6 0.25

0.6 0.024

0.6 0.024

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25 1.0

w

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C

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T

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Air Space

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Inorganic Insulation Board "C"

Inorganic Insulation Board "C"

Painted Black

Galvanized Metal Plate Unpainted

Galvanized Metal Plate Painted White

Galvanized Metal Plate Painted Black

Wood Paneling

Wall Mat (Plaster Type)

53
Table 4. Wallboard Surface Temperature Rise Measured During Tests of

Chimney Connector/Wall Protection Systems

Clearance to: 350°C

Stove Temperature

400°C 450°C

Test #

Wall

(mm/in)

Ceiling

(mm/ in)

Wall

(°C)

Ceiling

(°C)

Wall

(°C)

Ceiling

(°C)

Wall

(°C)

Ceiling

CO

25 76/3 241/9.5 36 62 43 72_

b 5^ 83.

28 76/3 241/9.5 25 54 29 64 32 21

29 76/3 241/9.5 28 53 33 60 38 21

30 76/3 457/18 15 38 19 39 20 46

31 76/3 457/18 24 33 27 38 33 43

37 76/3 457/18 37 4 45 4 50

38 76/3 457/18 £s «? 38 40 46 55_ 41

39 a 76/3 76/3 33 40 40 45 52 _57_

40 a 76/3 152/6 30 35 40 42 49 48

41 a 76/3 229/9 30 33 40 40 46 45

42 a 76/3 229/9 27 25 35 31 44 45

43a 76/3 152/6 26 26 33 30 42 37

44 a 76/3 76/3 25 34 35 33 43 37

45 a 76/3 229/9 24 29 29 36 42 43

46 a 76/3 152/6 29 36 39 42 49 48

47 a 76/3 76/3 26 38 35 46 47 55

48 a 76/3 229/9 27 31 37 38 51 46

49 a 76/3 152/6 29 34 38 42 53 53

50a 76/3 76/3 29 48 41 54_ 51_ 64_

Note: a Protected Ceilings, b Underlined data indicate failures

54
Ceiling

Wall

IClearances

"/'////////. //////// / ,

Connector pipes

Thermocouples

V//'/ Appliance

Figure 10. Relation of Stove and Celling Conneetor Pipe System to Wall and Ceiling Panels

55
CONNECTOR PIPE TESTS

VERTICAL WALL THERMOCOUPLE LOCATIONS

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17. FULL ROOM VALIDATION TESTS

Based on results obtained for radiant energy exposure tests of mock-up

wall panels shielded from hot appliance surfaces by various protection systems

(Part 1) and an evaluation of protection devices for mock-up wall and ceiling

panels exposed to chimney connector pipe systems (Part 2) a third series of

tests was conducted to evaluate the thermal effects of heating appliance and

chimney connector pipe combination systems in full room validation tests of

walls and ceilings. A total of 14 different protection devices were evaluated

in the study. Appliance and connector pipe exposure temperatures were 350,

400 and 450°C (662, 752 and 842°F). Temperature rise measurements were made

on the surfaces of unprotected walls and ceilings and on walls shielded by

various protection systems.

The full scale room ceiling provided satisfactory results for normal

operational exposures (350°C) but showed a need for protective devices when

exposed to temperatures generated by over fire test conditions of 400 and

450°C. Minimum clearances (between the appliance and full scale room wall

surface) determinations were made to establish compliance with code recommended temperature rise limitations.

18. TEST ROOM DESCRIPTION

A full size room with approximate dimensions of 3.6 x 3.6 x 2.4 m

(12 x 12 x 8 ft) high was constructed for these tests. Walls and ceilings

were made of 5/8 in thick gypsum wallboard. Figure 15 shows the locations for

the 24 gauge chromel-alumel thermocouples attached vertically and horizontally

62
to the exposed wall surface and across the ceiling. Spacing between thermocouples was 152 mm (6 in) and the output for each thermocouple was read

individually. Figure 16 shows the appliance with thermocouples attached to

the vertical "exposure side" of the fire box. The output from these parallel

connected thermocouples was used to monitor temperatures on the appliance

surface. Figure 17 illustrates the relation of the appliance and chimney

connector pipes to the test wall and ceiling. For these tests, the appliance

was mounted on a sled fitted with casters to allow for movement to any desired

clearance from the test wall. Figure 18 shows that portion of the wall

surface shielded by a protector plate system. The protector extended A57 mm

(18 in) beyond the sides and top edges of the appliance and 229 mm (9 in) to

either side of the 152 mm (6 in) diameter chimney connector pipe.

19. TESTING PROGRAM

19.1 Test Systems

Table 5 shows sketches of the wall/ ceiling test systems. The base gypsum

wallboard wall and ceiling was unprotected and painted white for system Rl

while for R2 the base material was painted black. System R3 consisted of a

white painted wall protected by a 25 mm (1 in) air space and a black painted

28 gauge sheet metal plate. For all remaining test systems, the base wall and

ceiling surface were painted black to maximize radiative absorption of energy.

For system R4 the wall was protected by alternating air space and metal plates

(24 gauge) painted black. R5 used an air space and sandwich panel consisting

of fiberglass between 24 gauge sheet metal plates (black). Systems R6, R7 and

R8 used a 13 m (1/2 in) thick insulation board (M) , as the protector, for R6

63
the board was offset from the wall by a 25 mm (1 In) air space and was

unpalnted. R7 used the same setup but the board surface was painted black.

R8 used fiberglass behind the board Instead of an air gap. The wall for

system R9 consisted of 13 mm (1/2 In) thick knotty pine paneling backed by

extruded polystyrene foam Insulation board. RIO used an air space and 24

gauge sheet metal plate (black) to protect the system used for R9. The

protection used for Rll and R12 consisted of a 28 gauge sheet metal plate

attached to a black painted Insulation board. Rll used an air gap; R12 did

not. System R13 used a protective package consisting of an air gap and

Insulation board sandwiched between 28 gauge plates painted black. R14 used a

brick wall and a 51 mm (2 In) air separation to protect the test wall surface.

For the purposes of these tests the test systems were evaluated under the

following conditions:

• Clearances to walls were varied from 76 mm to 1.07 m (3 to 42 in).

• Clearance to ceilings remained at 457 mm (18 in) for all tests.

• Appliance surface temperatures were 350, 400, and 450°C (662, 752,

and 842 °F).

19.2 Test Criteria

UL Standard for Room Heaters Solid Fuel Type UL 1482 First Edition [25],

was used as the test criteria:

64
• A surface temperature rise of 50 °C (90 °F) above room temperature is

allowed for protected surfaces.

• A surface temperature rise of 65°C (117°F) above room temperature is

allowed for unprotected surfaces.

20. TEST RESULTS

20.1 Walls

Surface temperature rise, typical for exposure tests on room walls is

shown in figures 19 and 20 for wood paneled wall R9. Table 6 lists all of the

wall systems and the range of temperature rise on the surfaces of the walls

along horizontal and vertical lines for tests at three different exposure

temperature levels where clearances between appliance and walls were varied

over a range from 1.07 m (42 in) to 76 mm (3 in). Plots of these data are

shown in figures 21 to 28. Based on an analysis of these data plots, table 7

lists the minimum clearances found necessary between an appliance and room

wall for three different test temperature levels in order to meet code

specified surface temperature rise requirements or limitations.

20.2 Ceilings

A typical surface temperature rise on a test ceiling is shown in figure

29 for the wood paneled wall system R9. Figure 30 shows the range of temperature rise for all room ceilings under conditions where clearances to room

walls were varied for tests at different exposure temperatures. Table 8 lists

65
the wall/ceiling systems and identifies the clearances to walls at which the

test ceiling registered a higher surface temperature than recommended

(65°C-117°F) by the code.

21. TEST OBSERVATIONS

21.1 Room Walls

An examination of the minimum clearance data for walls listed in Table 7

shows that:

(1) Unprotected systems Rl , R2 and R9 needed code recommended clearances

of 914 mm (36 in) for 350°C (662°F) exposures. Rl (WW) also passed

tests at 400°C (752°F) but the others did not. None passed at 450°C

(842°F).

(2) A total of 7 systems, R3 , R4 , R5 , Rll, R12, R13 and R14 provided for

clearance reductions to 76 mm (3 in) at the 350°C (662°F)

exposure. Except for R12 all of the systems had an air space

between the wallboard and protector and except for R14 (a brick

wall) all had the benefit of metal plate(s) for the exposed

surface. Systems with one metal plate were R3, Rll, and R12. At

exposures of 400°C System R12 showed a need for clearances greater

than 305 mm (12 in) and Rll and R3 required 76 mm (3 in) and 152 mm

(6 in) clearances respectively. At the 450°C (842°F) exposure all

of the one plate systems needed clearances greater than 305 mm (12

in). Systems with two metal plates R4 , R5 and R13 passed all of the

66
all of the exposure tests at 400 and 450°C (752 to 8A2°F). System

R14 (brick wall) required 229 mm (9 In) clearance at 400°C (752°F)

and 305 mm (12 In) clearance at 450°C (842°F).

(3) Three systems R6, R7 and R8 used a 12 mm (0.5 In) thick insulation

board as a protector for the base wallboard. R6 and R7 had an air

space between the protector and wallboard while R8 used fiberglass

insulation. Systems R6 and R7 passed exposure tests at 350 and

400° C (662 and 752 °F) at a clearance of 305 mm (12 in) but showed a

need for clearances greater than 305 mm (12 in) at 450°C (842°F).

System R8 passed the 350°C exposure test at the 305/mm (12 in)

clearance but showed a need for clearances greater than 457 mm (18

in) at the 400 and 450°C (752 and 842°F) exposures.

21.2 Room Ceilings

For this test series, all 14 gypsum wallboard ceilings were unprotected

and were located 457 mm (18 in) away from the horizontal chimney connector

pipe. The ceiling in system Rl was painted white while all others were

painted black.

(1) All test ceilings passed normal stove operational tests at 350 °C

(662°F). (Code limit is 65°C rise above room temperature.)

(2) Ceilings in 7 systems; Rl, R2, R3, R4, R5, R7 , and R8 met code

temperature requirements for overfire exposures at 400 and 450°C

(752 and 842°F).

67
(3) Ceilings in 7 systems; R6, R9 , RIO, Rll, R12, R13, and R14 failed to

meet code limits for the overfire conditions at 400 and 450°C (752

and 842°F).

(4) At the 400°C (752°F) exposure, the ceilings in systems R6, RIO, Rll,

R12 and R13 passed tests when the stove and chimney connector were

located 76 and 152 mm (3 and 6 in) away from the test wall however

when the separation to the wall was 304 mm (12 in) the ceilings

failed to meet code temperature requirements. Failing temperatures

were borderline ranging from 1 to 4°C above the 65°C limit.

(5) For the 450°C (842°F) exposures the failing ceilings showed temperature rise values varying from 2 to 12°C above the code limit.

Failures were recorded for 76 to 304 mm (3 to 12 in) clearances.

22. CONCLUSIONS

Based on an analysis of test results, the following conclusions are

drawn:

(1) For normal stove operational conditions 350°C (662°F) unprotected

room walls and ceilings showed code acceptable surface temperature

rise when tested at code recommended clearances; i.e., 914 mm

(36 in) between the stove surface and room wall and 457 mm (18 in)

between the ceiling and horizontal chimney connector pipe.

68
(2) When the stove was operated at overfire conditions i.e., 400-450°C

(752-842°F), clearances between unprotected room walls and the stove

surface had to be increased significantly, i.e., beyond 914 mm

(36 in).

(3) Thermal barriers, such as air space/metal plate and air

space/ insulation board were found effective in helping to reduce the

effects of radiant energy from hot stove surfaces on adjacent room

wall surfaces.

(4) Under normal operating conditions, 350°C (662°F), an air space/metal

plate system allowed for clearance reductions to 76 mm (3 in), while

an air space/insulation board system permitted reductions to 305 mm

(12 in).

(5) Room ceilings were found to need protective barriers to accommodate

overfire conditions such as a stove operating at 400 and 450°C (752

and 842 °F).

23 . RECOMMENDATIONS

From the tests on wall and ceiling protection systems (Parts I and II)

and the full room verification of the systems (Part III), several systems that

provide protection to combustible walls and ceilings were shown to be appropriate. Possible text for model building code specifications for wall and

ceiling protection is detailed below.

69
1. Clearances from residential heating appliances to combustible material

may be reduced if the combustible material is protected as described

in table 9 and in figures 31 to 35.

2. For clearance reduction systems using an air space between the

combustible wall and the wall protector, adequate air circulation

shall be provided by one of the following methods as shown in

figure 35:

• Adequate air circulation may be provided by leaving

all edges of the wall protector open with at least a

25 mm (1 in) air gap.

• If the wall protector is mounted on a single, flat

wall away from corners , adequate air circulation may

be provided by leaving only the bottom and top edges

or only the side and top edges open with at least a

25 mm (1 in) air gap.

• Wall protectors that cover two walls in a corner shall

be open at the bottom and top edges with at least a

25 mm (1 in) air gap.

3. All clearances shall be measured from the outer surface of the

combustible material to the nearest point on the surface of the

appliance, disregarding any intervening protection applied to the

combustible material.

70
4. All clearances provided between residential heating appliances and

combustible materials shall be large enough so as to maintain

sufficient clearances between both the chimney connector and the

appliance and combustible material.

71
Table 5. Fourteen Room Wall-Ceiling Systems Tested

R1

VAW/AW/A WW

r

R6

S? mm

*

.

< *<W//W//A WB

R11

R2

''//////////A WB

r

00 £ <N|

R3

W/W//IWB

00 CO j* _< '*y//////;///A wb

^ I

R7 g | R12

**y;;;/;/;////A wb

1i i1 r

0(3(0

*LjtJl& awB

R8

do o o

> < cm 2

r

R13

Qj COo

*Y//////AW/A WB

R4

CD^ (OQ-r

R9

Y///////////A WB ^ << m

R14

^^^IWB

R5

00 00 * < w " **y///////////A WB

R10

00

72
Table 6. Range of Surface Temperature Rise Along the Horizontal and Vertical Lines of Room Walls

System

Wall

Clearance

(mm/In)

HORIZONTAL

350*C

Stove Temperature

400°C 450°C

Rl 914/36 23 - 47 34 - 65 44 79 610/24 30 - 73* 39 - 96 45 111 457/18

305/12

29 -

27 - IT117

39 -

37 -

122 155 4643143 179

R2 914/36 24 - 53 35 - 68 43 - 81 610/24 29 -

12. 39 - 100 48 - 122 457/18 29 - 100 40 - 126 48 - 151

R3 305/12 2 - 32 3 - 43 1 - 52 152/6 3 - 29 2 - 37 5 - 47 76/3 4 - 26 4 - 35 8 - 43

R4 152/6 7 - 25 8 - 36 10 - 47 76/3 5 - 22 8 - 31 9 - 39

R5 152/6 - 25 - 36 - 41 76/3 - 21 - 29 - 34

R6 305/12

152/6

76/3

810

10

3850 il1810

19

5160

_76

1416

21

66

72

84

*7 457/18 29 43 10 ii

305/12 10 39 15 4T 40 55 152/6

76/3

10 54 16

16 67 21

32

18 76

86_

R8 457/18 7 - 39 14 47 19 67 305/12 10 - 42 12 68 — —

152/6

76/3

9 -

20 -

72 J!

9

13 90100 2216 107

124

R9 1.06m/ 42 — — 28 - 55 34 68 914/36 29 - 51 30 - 64 36 21

RIO 305/12 3 - 45 6 - 54 8 71 152/6 3 - 36 5 - 49 7 71 76/3 3 - 50 8 - 74_ 15 94_

Rll 305/12 - 39 - 50 61 152/6 - 34 - 49 60 76/3 - 26 - 38 48

R12 305/12

152/6

--

39

34 --

55

44

64

58 76/3 - 16 - 36 48

R13 305/12 - 27 - 40 44 152/6 - 22 - 27 35 76/3 - 46 - 18 ii

R14 914/36 - 10 - 12 14 610/24 - 18 - 23 23 305/12 — — - 37 42 229/9 — — - 43 48 152/6 - 41 - 53 56 76/3 - 43 - 61 68

Note: "Underlined temperatures exceed code limits.

73
System

Wall

Clearance

(mm/ in)

Table 6. Continued

VERTICAL

Stove Temperature

350°C 400°C 450°C

Rl

R2

R3

R4

R5

R6

R7

R8

R9

RIO

Rll

R12

R13

R14

914/36

610/24

914/36

610/24

305/12

152/6

76/3

152/6

76/3

152/6

76/3

305/12

152/6

76/3

457/18

305/12

152/6

76/3

457/18

305/12

152/6

1.06m/42

914/36

305/12

152/6

76/3

305/12

152/6

76/3

305/12

152/6

76/3

305/12

152/6

76/3

610/24

305/12

229/9

152/6

76/3

30 - 35 30 - 50

30 - 50 30 - 79

- 32

- 34

- 39

- 4 - 6

- 5 - 6

6 - 39

1 - 55

- 69

4 - 33

5 - 42

3 - ii

- 22 - 49

35 - 47 37 - 70394259

77

84

22 - 53

5 - 31 - 31 - 59 - 19 - 21 - 22

- 19 3 - 23

1 - 24

- 18 - 21 0-32

18

32 - 66 38 - 98

1 - 43 - 41 - 116

- 5 - 7

- 5 - 7

7 - 48

2 - 63 - 21

4 - 37

5 - 35

5 - 48

6 - 55_

- 52

- 67 - 74

35 - 74_ 25 - 64

3 - 39

1 - 56 - 80

- 20 - 25 - 28

1 - 24

5 - 26

4 - 29

- 24 - 26 - 38

- 21

3 - 32

4 - 44

3 -

3 -

4846 4-^4

4-67

- 58 - 109 - 161

- 6 - 9

- 6 - 9

9 - 54

8 - 76

- 11

5 - 42

7 - 56

8 - 63

- 35 - 62

- ^9

31 - 80

32 - 21

6 - 53

4 - 82

- 107

- 18 - 27 - 33

1 - 26

4 - 29

5 - 34

- 28 - 32

- 41

- 22

- 43

3 - 52

5 - 59 4-75

74
Table 7. Minimum Clearances Needed Between Appliance and Exposed

Wall Surfaces to Meet Code Requirements

System No. Wall Ceiling

Stove Temperatures

350°C 400°C 450°C

Minimum Clearance (mm/ in)

Rl

R2

R3

R4

R5

R6

R7

R8

R9

RIO

Rll

R12

R13

R14

(WW) WW

(WB) WB

(WW, A, 28GB) WB

(WB, A, 24GB, A, 24GB) WB

(WB, A, 24GB, FG, 24GB) WB

(WB, A, M) WB

(WB, A, MB) WB

(WB, FG, MB) WB

(WB, S, P) WB

(WB, S, P, A, 24GB) WB

(WB, A, MB, 28G) WB

(WB, MB, 28G) WB

(WB, A, 28GB, MB, 28GB) WB

(WB, AA, BR) WB

914/36 914/36 > 914/36

914/36 > 914/36 > 914/36

76/3 152/6 > 305/12

76/3 76/3 76/3

76/3 76/3 76/3

305/12 > 305/12 > 305/12

305/12 457/18 > 305/12

305/12 > 457/18 > 457/18

914/36 >1067/42 >1067/42

152/6 > 305/12 > 305/12

76/3 76/3 > 305/12

76/3 > 305/12 > 305/12

76/3 76/3 76/3

76/3 229/9 305/12

75
Table 8. Temperatures At Overflre Conditions for Systems Showing

High Ceiling Surface Temperatures

System No. Wall Ceiling

Stove Temperature

Wall Clearance mm (in)

400 450 450 450

305/12 76/3 152/6 305/12

(°C) CO (°C) (°C)

R6 (WB, A, M) (WB) 68a

Rll (WB, A, MB, 28GB) (WB) 67

R12 (WB, MB, 28G) (WB) 68

R13 (WB, A, 28GB, MB, 28GB) (WB) 67

R14 (WB, AA, BR) (WB) -

67

71

69

77

74

69

Note: aAcceptance level 65°C

76
Table 9. Reduction of Appliance Clearance with Specified Forms of Protection

Clearance Reduction System

Applied to and Covering all

Combustible surfaces within

the distance specified as required clearance with no protection.

Minimum

Allowable

Clearance

(Percent)

of Unprotected

Clearance

When the required clearance with

no protection is 914 mm (36 in)

,

the clearances below are the

Minimum Allowable clearance.

As Wall

Protector

As Ceiling

Protector

As Wall

Protector

(mm/in)

As Ceiling

Protector

(mm/ in)

(a) 90 mm (3-1/2 in)

thick masonry wall with- 67%

out ventilated air space

(b) 13 mm (1/2 in) thick

insulation board over 25 mm

(1 in) glass fiber or 50%

mineral wool batts

(c) 0.61 mm (0.024 in)

(24 gauge) sheet metal over

25 mm (1 in) glass fiber

or mineral wool batts 33%

reinforced with wire, or equivalent on rear face

with ventilated air space

(d) 90 mm (3-1/2 in) thick

masonry wall with ventilated 33%

air space

(e) 0.61 mm (0.024 in)

(24 gauge) sheet metal with 33%

ventilated air space

(f) 13 mm (1/2 in)

thick insulation board 33%

with ventilated air space

(g) 0.61 mm (0.024 in)

(24 gauge) sheet metal with

ventilated air space over 17%

0.61 (0.024 in) (24 gage)

sheet metal with ventilated

air space

(h) 25 mm (1 in) glass fiber

or mineral wool batts sandwiched between two sheets 17%

0.61 mm (0.024 in) (24 gauge)

sheet metal with ventilated

space.

67%

610/24

457/18 610/24

50% 305/12 457/18

50%

50%

33%

305/12

305/12

305/12

152/6

457/18

457/18

305/12

33% 152/6 305/12

77
NOTES - Table 9

Spacers and ties shall be of noncombustible material. No spacers or ties

shall be used directly behind appliance or connector.

With all clearance reduction systems using a ventilated air space, adequate

air circulation shall be provided as described. There shall be at least

25 mm (1 in) between the clearance reduction system and combustible walls and

ceilings for clearance reduction systems using a ventilated air space.

Mineral wool batts (blanket or board) shall have a minimum density of

128 kg/m3 (8 lb per ft 3

) and have a minimum melting point of 816°C (1500°F).

Insulation material used as part of clearance reduction system shall have a thermal conductivity of 1.0 (BTU-in)/(sq ft-hr-°F) or less.

If a single wall connector passes through the masonry wall, there shall be at

least 13 mm (1/2 in) of open ventilated air space between the connector and

the masonry.

There shall be at least 25 mm (1 in) between the appliance and the protector.

In no case shall the clearance between the appliance and the wall surface be

reduced below that allowed in the table.

Clearances In front of the loading door and/or a6h removal door of the

appliance shall not be reduced from those required with no protection.

o All clearances and thicknesses are minimums, larger clearances and

thicknesses are acceptable.

q To calculate the minimum allowable clearance , the following formula may be

used: C = C x (l-R/100); C Is the minimum allowable clearance, C is

the required clearance with no protection, and R is the maximum allowable

reduction in clearance.

78
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of a Room Wall (System R14)

92
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94
COMBUSTBLE WALL

SL m a.

TOP VIEW _0_ J.

o

NON-COMRUSTBLE SPACERS 17

DO NOT USE SPACERS DBECTLY

BEHIND APPLIAMCE OR CONNECTOR

WALL

LEAVE 1" CLEARANCE TO FLOOR ADJACENT WALLS, CEILM, FOR All CBCULATBN NON-COMWSTBLE FASTENERS AROUND THE PERMETER

FRONT VIEW

Figure 31. Clearance Reduction System for Residential Heating

Appliance

95
1" AIR SPACE AROUND PERNETER

AND BEHMD CLEARANCE REDUCTION SYSTEM

CLEARANCE TO COMBUSTBLE

WALL WITH PROTECTION AS

SPECIF ED M TABLE 5-S[b) OR 8-7|b]

FLOOR PROTECTION

Figure 32. Clearance Reduction System for Residential Heating

Appliance

96
MASONRY WALL TIE

HAIL OR SCREW ANCHOR

CLEARAHCE REDUCTIOH SYSTEM

1" NON-COMBUSTIBLE SPACER SUCH AS STACKED WASHERS, SMALL DIAMETER PPE, TURK. OR ELECTRICAL CONDUIT. MASONRY WAILS MAY BE ATTACHED TO COMBUSTIBLE WALLS

USING WALL TICS

.

DO NOT USE SPACERS DIRECTLY BEHIND APPLIANCE OR CONNECTOR.

Figure 33. Masonry Clearance Reduction System

97
COMBUSTIBLE WALL

1" MIN. AIRSPACE BETWEEN MASONRY AND COMBUSTIBLE WALL

4" NOMINAL BRICK WALL

BOTTOM AND TOP COURSE

OF BRICKS STA66ERED FOR

VENTILATION

CORRUGATED METAL WALL

TIES

Note: DO NOT PLACE MASONRY

WALL TIES DIRECTLY BEHIND APPLIANCE OR CONNECTOR

A STRIP OF HEAVY GAGE STEEL MAY

BE USED FOR ADDED SUPPORT

MASONRY CLEARANCE REDUCTION SYSTEM

Figure 34. Non-Combustible Spaces for Clearances Systems

98
WALL PROTECTOR MOUNTED

WITH ALL EDGES OPEN Sm 8-7.2.4.1

MOUNTED WITH SUE

AND TOP EDGES OPEN

MOUNTED WITH TOP AND BOTTOM EDGES OPEN

WALL PROTECTOR MOUNTED

ON SMGLE FLAT WALL Sm 9-UA.2

MUST BE MOUNTED WITH TOP AND BOTTOM EDGES OPEN

WALL PROTECTOR INSTALLED

IN CORNER Sm 8-7.2.4.3

Figure 35. Air Movement Around Protector Plates or Panels

99
24 . REFERENCES

[1] Peacock, R.D., A Review of Fire Incidents, Model Building Codes, and

Standards Related to Wood-Burning Appliances, Nat. Bur. Stand. (U.S.),

NBSIR 79-1731 (May 1979).

[2] Peacock, R.D., et al., Fire Safety of Wood-Burning Appliances, Part 1:

State of the Art Review and Fire Tests, Volumes I and II, Nat. Bur.

Stand. (U.S.), NBSIR 80-2140 (Nov. 1980).

[3] Peacock, R.D., A Review of Fire Incidents Related to Wood-Burning

Appliances, Wood Energy Institute, Proceedings of Wood Heating

Seminar IV, Portland, OR, March 21-24, 1979, 43-46.

14] Shelton, J.W., Analysis of Fire Reports on File in the Massachusetts

State Fire Marshal's Office Relating to Wood and Coal Heating Equipment,

Nat. Bur. Stand. (U.S.), NBS-GCR-78-149 (Nov. 1978).

[5] The BOCA Basic Building Code/1981, Model Building Regulations for the

Protection of Public Health, Safety and Welfare, Eighth Edition,

Building Officials and Code Administrators International, Homewood, IL

[6] The BOCA Basic Mechanical Code/ 1981, Model Mechnical Regulations for the

Protection of Public Health, Safety and Welfare, Fourth Edition,

Building Officials and Code Administrators International, Homewood, IL

(1981).

[7] The National Building Code, 1976 Edition, American Insurance

Association, New York, NY (1976).

[8] Chimneys, Fireplaces, Vents and Solid Fuel Burning Appliances, NFPA

211-1984, National Fire Protection Associaton, Boston, MA (1978).

[9] Standard Building Code, 1982 Edition, Southern Building Code Congress,

International, Inc., Birmingham, AL (1982).

[10] Amendments to the Standard Building Code, 1977 and 1978 Revisions to the

1976 Edition, Southern Building Code Congress, International, Inc.,

Birmingham, AL (1978).

[11] Uniform Building Code, 1982 Edition, International Conference Building

Officials (1982).

[12] 1977 Supplement to the Uniform Building Code, U.B.C. Standards, Uniform

Housing Code, Uniform Code for the Abatement of Dangerous Buildings and

the Uniform Fire Code, International Conference of Building Officials

(1982).

[13] Manual on Clearances for Heat Producing Appliances, NFPA 89M-1976,

National Fire Protection Association, Quincy, MA (1978).

[14] Voight, G.Q., Fire Hazard of Domestic Heating Installations, Nat. Bur.

Stand. (U.S.), NBS Research Paper RP596 (Sept. 1933).

100
[15] Neale, J. A. , Clearances and Insulation of Heating Appliances,

Underwriters Laboratories, Inc., UL Bulletin of Research #27

(Feb. 1943).

[16] Lawson, D.I., Fox, L.L. , and Webster, C.T. , The Heating of Panels by

Flue Pipes, Fire Research Special Report No. 1, Fire Protection

Association, London, England (1952).

[17] Lawson, D.I. and Simms, D.L., The Ignition of Wood by Radiation, British

Journal of Applied Physics, Vol. 3, 288-292 (Sept. 1952).

[18] Shoub, H., Survey of Literature on the Safty of Residential Chimneys and

Firepalces, Nat. Bur. Stand. (U.S.), NBS Misc. Pub. 252 (Dec. 1963).

[19] Prefabricated Metal Chimneys, National Bureau of Standards, Fire

Research Section, unpublished reports to Federal Public Housing

Authority (1941-1945).

[20] Temperatures Developed in Chimneys for Low Cost Houses, Nat. Bur. Stand.

(U.S.), Tech. News Bull. 328 (Aug. 1944).

[21] Fox, L.L. and Whittaker, D., Some Measurements of Temperatures of Metal

Flues of Domestic Heating Appliances, Journal of the Institution of

Heating and Ventilation Engineers, Vol. 23, 183-192 (Aug. 1955).

[22] Standard for Chimneys, Factory-Built Residential Type and Building

Appliance—UL 103, Underwriters Laboratories, Inc., Northbrook, IL,

(March 1971).

[23] Peacock, R.D., et al, Fire Safety of Wood Burning Appliances, Part 1: State of the Art Review and Fire Tests, Nat. Bur. Stds. (U.S.),

NBSIR 80-2140 (1980).

[24] Standard for Room Heaters, Solid Fuel Type—UL 1482, First Edition,

Underwriters Laboratories, Inc., Northbrook, IL (Aug. 1979).

[25] Mitchell, N.D., New Light on Self-Ignition, NFPA Quarterly, Vol. 45,

No. 2, 165-172 (Oct. 1951).

[26] MacLean, J.D., Effect of Heat on Properties and Serviceability of

Wood: Experiments on Thin Wood Specimens, Forest Products Laboratory

Report No. R1471, Madison, WI (1945).

[27] MacLean, J.D., Rate of Disintegration of Wood Under Different Heating

Conditions, American Wood-Preservers Association (1951).

[28] McGuire, J.H., Limiting Safe Surface Temperature of Combustible

Materials, Fire Technology, Vol. 5, No. 3 (Aug. 1969).

[29] Ignition and Charring Temperatures of Wood, Forest Products Laboratory

Report No. 1464, Madison, WI (Jan. 1958).

[30] Shelton, J.W., Wood Heat Safety, Garden Way Publishing, Charlotte, VT

(Sept. 1979).

101
[31] Matson, A.F., Dufori, R.E., and Breen, J.F., Performance of Type B Gas

Vents for Gas-Fired Appliances, Part II, Survey of Available Information

on Ignition of Wood Exposed to Moderately Elevated Temperatures,

Underwriters Laboratories, Inc., Bulletin of Research, No. 51,

Morthbrook, IL (May 1959).

102
NDS-114A (rev. 2-ao

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBS/TN-1205

2. Performing Organ. Report No, 3. Publication Date December 1984

4. TITLE AND SUBTITLE

CLEARANCES AND METHODS OF PROTECTION FOR WALL AND CEILING

SURFACES EXPOSED TO RADIANT HEATING APPLIANCES

5. AUTHOR(S)

Joseph J. Loftus, Richard D. Peacock

6. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions)

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

GAITHERSBURG, MD 20899

7. Contract/Grant No.

8. Type of Report & Period Covered

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State, ZIP)

U.S. Department of Energy and U.S. Consumer Product Safety Commission

Washington, DC 20585 Washington, DC 20207

10. SUPPLEMENTARY NOTES

"2 Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

The Center for Fire Research in the National Bureau of Standards has evaluated the fire

hazard potential associated with the installation and use of solid fuel burning appliances (and chimney connectors) in residential housing.

For this three-part study, mock-up and full scale room walls and ceilings were exposed

to radiant energy from chimney connectors and an appliance operated under normal and

overfire conditions at various distances or clearances from the room members. Peak surface temperature rise measurements were made on exposed and protected walls and ceilings

and comparisons were made with surface temperature rise limitations established by

building and fire codes.

In the testing program, a total of 19 different thermal barriers or protection systems

were evaluated and a number were found capable of providing adequate thermal protection

Particularly effective were those systems which used a sheet metal plate or two sheet

metal plates with an insulative layer between them mounted in front of a wall or ceiling

and separated from the room surface by a 25 mm (1 in) air space. This provision for air

to circulate freely between a room member and its protector proved to be an extremely

important factor in providing for increased fire safety.

Based on these findings, recommendations are made which building and fire code officials

may find useful in preparing fire safety codes and regulations designed to protect the consumer from personal and property damage caused by unwanted fires.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

ceilings; chimneys; fire codes; fire protection; fire tests; interior finishes;

radiant energy; residential buildings; stoves; walls.

13. AVAILABILITY

[X] Unlimited

|

| For Official Distribution. Do Not Release to NTIS

QT] Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.

\2Z] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

112

15. Price

USCOMM-OC 6043-P80
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