Auto-ignition temperatures

Alcohol Open cup Closed cup Lower Upper Auto ignition temperature, °C... 

Health and Safety Factors. Sulfur monochloride is highly toxic and irritating by inhalation, and is corrosive to skin and eyes (156). The OSHA permissible exposure limit is 1 ppm (6 mg/m ). Pulmonary edema may result from inhalation. Because its vapor cannot be tolerated even at low concentrations, its presence serves as a warning factor. Sulfur monochloride is not highly flammable, having flash poiats of 118°C (closed-cup) and 130°C (open-cup) and an auto-ignition temperature of 234°C. 

Autoignition Temperature (AIT) The auto ignition temperature of a substanee, whether solid, liquid, or gaseous, is the minimum temperature required to initiate or eause self-sustained eombustion, in air, with no other souree of ignition. 

Flammable limits, flash point, auto-ignition temperature etc. 

Auto-Ignition Temperature — the temperature at whieh ignition oeeurs without an ignition souree and the material continues to burn without further heat input. 

A pump was being dismantled for repair. When the cover was removed, hot oil, above its auto-ignition temperature, came out and caught fire. Three men were killed, and the plant was destroyed. Examination of the wreckage after the fire showed that the pump suction valve v/as open and the drain valve shut [3]. 

Unexpected concentration of oxygen can occur when compressed air is dried or purified by pas.sing it over certain types of molecular sieves. Nitrogen is absorbed preferentially after regeneration, and the air first produced may be rich in oxygen. This can widen flammability limits and lower auto-ignition temperatures. At least one explosion has occurred as a result. If possible, use Type 3A molecular sieves [21]. 

The heat transfer section of a plant was filled with oil after maintenance by opening a vent at the highest point and pumping oil into the system until it overflowed out of the vent. The overflow should have been collected in a bucket, but sometimes a bucket was not used, or the bucket was overfilled. Nobody worried about small spillages because the Hash point of the oil was above ambient temperature and its boiling point and auto-ignition temperature were both above 300°C. 

Insulation that has been impregnated with heavy oil—or any other organic liquid—should be removed as soon as possible before tbe oil ignites. If oil is left in contact with insulation materials, the auto-ignition temperature is lowered by 100-200°C [8] (see Section 7.3.2). 

An entirely different diesel hazard is compression of a pocket of air and flammable vapor trapped in a vessel or pipeline by a column of liquid. If the pressure of the liquid rises, the air is compressed, and the heat developed may heat the vapor above its auto-ignition temperature [13]. 

Oil spillages onto warm, absorbent materials, such as insulation, also have a limited life (see Sections 7.3.2 and 12.4.4). The oil soon decomposes to materials with a low auto-ignition temperature and self-ignites. As many insulation fires have started in this way, oil-soaked insulation should be removed without delay. Linseed oil ignites particularly easily. This has been known since at least 1925 nevertheless, in 1965 some cloths used to apply linseed oil to laboratory benches were not burned as directed but dropped into a waste bin. A fire started after a few hours and destroyed the laboratory [17J. Reference 18 lists substances that are liable to self-heat, and Reference 19 includes references to a number of incidents that have occuiTed involving substances as diverse as wood shavings, tobacco, milk powder, and soap powder. 

Liquefied petroleum gas (LPG) was involved in 17% of the incidents (see Chapter 8), followed by heavy oils (see Section 12.4), gasoline, hydrogen, and hydrocarbon gases. Heavy oils are involved in so many incidents because they are often handled above their auto-ignition temperature and because they are involved in foamovers. 

A, = vent area, sq meters or sq ft A = total wetted surface area, sq ft AIT = auto-ignition temperature... 

Explosive limits in air, % by vol. Auto- ignition temperature. °F Specific gravity (water = 1.0) Vapor density (air = 1.0) Melting point. °r Boiling point or range. °F Water solu- bility Suitable extin- guishing agents Hazard... 

AUTO-iGNiTiON TEMPERATURE The minimum temperature required to initiate or cause self-sustained combustion of material in the absence of any external source of energy. (Values may change significantly with geometry, gas/vapour concentration, and if catalyst is present.)... 

Latent heat of sublimation at -84°C Latent heat of fusion at triple point Flammable limits in air Auto-ignition temperature Gross heat of combustion at 15.6°C, 1 atm Specific heat, gas at 25°C, 1 atm Cp Cv... 

VII -Liquids with auto-ignition temperature less than or equal to... 

Activated carbon showed an auto-ignition temperature in flowing air of 452-518°C. Presence of 5% of the base ( triethylenediamine ) adsorbed on the carbon reduced the AIT to 230-260°C. At high air flow rates an exotherm was seen at 230-260°, but ignition did not then occur until 500°C. 

Drying 2-aminothiazole in an oven without forced air circulation caused development of hot spots and eventual ignition. It has a low auto-ignition temperature and will ignite after 3.5 h at 100°C. 

The auto-ignition temperatures of various halogenated hydrocarbons in presence of chlorine are considerably below the corresponding values in air. Examples are (in °C) chloromethane 215 (618 in air) dichloromethane 262 (556) 1,2-dichloropropane 180 (555°C). Flammability limits are usually wider in chlorine... 

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