by Tony Cafe
Reproduced from "Firepoint" magazine - Journal of Australian Fire Investigators.
At the fire scene the investigator essentially studies the effect of heat on the various materials which survived the fire. From this study, the investigator determines the nature of the fire, its progress from the area of origin and hopefully the cause of ignition. To successfully achieve this goal the investigator needs to refer to the scientific literature for the physical constants of the various materials found at the fire scene because the investigator's conclusions must be reached using a logical and scientific methodology.
The following tables should be of help to the fire investigator in understanding the cause and progress of the fire. The information has been extracted from various sources such as Kirk's Fire Investigation, Cooke & Ide's Principles of Fire Investigation, John N. Cardoulis' The Art and Science of Fire Investigation (1990) and the Fire Protection Handbook. All temperatures are in degrees Celsius and it is noted there exists some discrepancies in the literature of the various physical constants of materials and so the temperatures and constants should be treated as approximates.
INDEX OF TABLES
- TEMPERATURES AT FIRES
- 1.1 SOURCES OF IGNITION - GENERAL TEMPERATURES
- 1.2 COLOR TEMPERATURES OF HEAT
- 1.3 TEMPERATURES DURING BUILDING FIRES
- PHYSICAL CONSTANTS OF MATERIALS
- TEMPERATURE INDICATORS
- FIRE CAUSES
1. TEMPERATURES AT FIRES
1.1 SOURCES OF IGNITION - GENERAL TEMPERATURES
Source
Temperature (Celsius)
Cigarettes - ventilated
400°-780°
Cigarettes - unventilated conditions
288°
Cigarettes - insulated and smoldering
510°-621°
Match
600°-800°
Candle flame
600°-1400°
Stove element
>550°
Fluorescent light
60°-80°
Incandescent light
100°-300°
Tungsten halogen light
600°-900°
Electrical arcing
to 3750°
Electrical spark
1316°
Lightning
30000°
Oxyacetylene
3300°
Industrial furnaces
1700°
Bunsen burner
1570°
1.2 COLOR TEMPERATURES OF HEAT
Dull red
500°-600°
Dark red
600°-800°
Bright red
800°-1000°
Yellow red
1000°-1200°
Bright yellow
1200°-1400°
White
1400°-1600°
1.3 TEMPERATURES DURING BUILDING FIRES
Hot gas layer
600°-1000°
Floor temperature
>180°
Glowing smoldering combustion
to 600°
Flashover
>600°
Glowing coals
to 1300°
2. PHYSICAL CONSTANTS OF MATERIALS
Reactions to temperature exposure
Reaction
Temperature (Celsius)
Wood slowly chars*
120°-150°
Decayed wood ignites
150°
Ignition temp of various woods
190°-260°
Paper yellows
150°
Paper ignites
218°-246°
Oil soaked lagging ignites
190°-220°
Leather ignites
212°
Hay ignites
172°
Coal ignites
400°-500°
* wood chars at a rate of approximately 30-50 mm/hour
Melting points and ignition temperatures
Plastic
Melting Point
RangeIgnition Temperature
ABS
88°-125°
416°
Acrylics
91°-125°
560°
Cellulosics
49°-121°
475°-540°
Nylons
160°-275°
424°-532°
Polycarbonate
140°-150°
580°
Polyesters
220°-268°
432°-488°
Polyethylene ld
107°-124°
349°
Polyethylene hd
122°-137°
349°
Polypropylene
158°-168°
570°
Polystyrene
100°-120°
488°-496°
Polyurethanes
85°-121°
416°
PTFE
327°
530°
P.vinylideneclor
212°
454°
PVC
75°-110°
435°-557°
Wool
228°-230°
Cotton
250°
Rubber
260°-316°
Melting points and flame colours
(o) & (r) denote oxidizing and reducing conditions respectively
Metal
Melting Point
Flame Colour
Aluminium
660°
Colorless
Copper
1080°
Green (o) Red (r)
Lead
327°
Colorless
Tin
232°
Colorless
Bismuth
271°
Colorless
Zinc
419°
Colorless
Aluminium alloy
600°
Colorless
Antimony
630°
Colorless
Magnesium
651°
Colorless
Brass
900°-1000°
Green (o) Red (r)
Silver
961°
Colorless
Bronze
1000°
Green (o) Red (r)
Gold
1063°
Cast iron
1200°-1350°
Yellow-brown
Manganese
1260°
Violet (o)
Nickel
1450°
Brown-Red
Cobalt
1490°
Blue
Steel
1100°-1600°
Brown-Red
Platinum
1770°
Titanium
1670°
Chromium
1900°
Green
Tungsten
3410°
Solder 60/40
183°
Electric fuses
371°
Carbon
3730°
Pure iron
1535°
Boiling points, flash points, ignition temperature and heat of combustion
Liquid
Boiling Point
Flash Point
Ignition Temperature
Heat of Combustion
(kilocalories per gram)Kerosene
175°-260°
38°-74°
229°
11
Gasoline
40°-190°
-43°
257°
11.5
Stove oil
190°-290°
Diesel
190°-340°
69°
399°
Fuel
200°-350°
Brake fluid
190°
Engine oil
150°-230°
260°-371°
Acetone
57°
-20°
465°
Benzene
80°
-11°
560°
10
Octane
126°
13°
220°
11.4
Pet ether
-18°
288°
Gum turpentine
37°
Spirit turpentine
135°-175°
35°
253°
Alcohol
78°
13°
365°
7.1
Ethylene glycol
111°
413°
Styrene
31°-37°
490°
White spirits
150°-200°
35°
232°
Asphalt
38°-121°
538°
Paint thinners
39°
245°
Paraffin wax
199°
* fire point is approximately 10°-50° above flash point
* cooking oil spontaneously combusts at 310°-360°
* temperature of flame from burning petrol is 471°-560°
Upper & lower flammable limits & ignition temperature
Gas
UFL %
LFL %
Ignition Temperature
Propane
9.6
2.15
466°
Butane
8.5
1.9
405°
Natural gas
15
4.7
482°-632°
Hydrogen
75
4
400°
Acetylene
3
65
335°
Appearance
Temperature
Yellow
320°
Brown
350°
Purple
400°
Blue
450°
* loses 50% of its structural strength and sags at 550°
* melt point of steel 1100°-1650°
Appearance
Temperature
Reddish pink - reddish brown
300°
Gray
300°-1000°
Buff
>1000°
Sinters and yellowish
>1200°
* sand and sandstone becomes friable at 573°
* wall masonry collapses at 760°
Effect
Soda
Borosilicate
Very slight distortion
700°
750°
Slight distortion
750°
800°
Considerable distortion
800°
850°
Medium fluid flow
850°
900°
Liquid flow
900°
950°
* glass thermally cracks at 90°-120°
Effect
Resin chars & slowly blackens
288°
Resin chars quickly
400°
Fibers becomes light gray
482°
Fibers fuse
593°
Fibers melt
649°
- Defective or left on heating or cooking equipment
- Defective chimney or flue
- Hot ashes or coals
- Combustibles near heaters
- Smoking or matches
- Electrical
- Rubbish fires
- Chimney or bushfire sparks on roof
- Welding and cutting
- Friction sparks from clashing metals
- Overheating of machinery
- Candles
- Poor storage of flammable liquids
- Lightning
- Children and matches
- Spontaneous ignition
- Gas and gas appliances
- Presence of flammable liquids
- Multiple points of origin
- Use of trailers, timing devices
- Presence of explosion
- Sign of forced entry
- Sign of contents removed before the fire or replaced with inferior goods
- Signs of tampering with gas or electric appliances or sprinklers
- Signs of artificial drafts eg holes in walls
- Rapid onset of fire, higher than normal temperatures closet fires
- Other crime committed