Burning tests, sustained

Table I - Summary of Sustained Burning Test Results...

The sustained burning test was originally developed for British Standard BS-3900 and adapted by ASTM. The purpose of the test is to determine the sustained burning characteristics of solvents by direct experiment rather than by deducing characteristics from flash point data. Mixtures of some flammable liquids (e.g., alcohol and water) are classified as flammable based on the closed-cup flash point method. Some mixtures may be classed as flammable even though they do not sustain burning. The test is performed in a block of aluminum with a concave depression called a well. The liquid under test is heated to a temperature of 49 C and a flame is passed over the well and held in position for 15 s. The specimen is observed to determine if it can sustain burning. 

D4206, Sustained burning test by Seta flash X X X X... 

The autoignition temperature is the minimum temperature required for self-sustained combustion in the absence of an external ignition source. The value depends on specified test conditions. Tht flammable (explosive) limits specify the range of concentration of the vapor in air (in percent by volume) for which a flame can propagate. Below the lower flammable limit, the gas mixture is too lean to burn above the flammable limit, the mixture is too rich. Additional compounds can be found in National Fire Protection Association, National Fire Protection Handbook, 14th ed., 1991. 

The criteria for insensitive explosives subjected to ha2ard tests permit no reaction more violent than burning in slow and fast cook-off tests and fragment and bullet tests, no propagation in sympathetic detonation tests, no detonation when stmck by a shaped charge jet, no sustained burning when hit by a small fragment, and such special tests as may be required by the use of the explosive. 

Artificial surfaces must be resistant to cigarette bums, vandaUsm, and other harm. Fire resistance is most critically evaluated by the NBS flooring radiant panel test (10). In this test, a gas-fired panel maintains a heat flux, impinging on the sample to be tested, between 1.1 W/cm at one end and 0.1 W/cm at the other. The result of the bum is reported as the flux needed to sustain flame propagation in the sample. Higher values denote greater resistance to burning results depend on material and surface constmction. Polypropylene turf materials are characterized by critical radiant flux indexes which are considerably lower than those for nylon and acryflc polymers (qv) (11). 

FLASH POINT. The lowest temperature at which an oil will volatilize to yield sufficient vapor to form with air an inflammable gaseous mixture, demonstrable through the production of a flush on comacl w ith a small open Hume. The flash point occurs at a temperature lower than the burning point, w hich is the lowest temperature at which the production of combustible gas occurs rapidly enough in support a steady flame. It is also m be noted that the flash point is the temperature of formation, under the test conditions, of the losver explosive mixture of the substance tested, with air. iThc higher explosive mixture is the maximum concentration of vapor, with air. which will sustain combustion.)... 

Therefore, closed box tests give a complete product yield of burning from well-ventilated to under-ventilated conditions, but without giving any indication of how the yield varies with fire condition. They are not generally able to sustain flaming combustion in under-ventilated conditions, where the toxic hazard is usually the greatest. Another potential source of error may occur as the fire effluent is heated and excess pressure is released or stickier components within the effluent, such as hydrogen chloride are deposited onto the walls of the cabinet. 

Sustained burning at next lower test level Nitrogen purged atmosphere during tests... 

Application of these data to CASBL show that most water and/ or solvent-wet propellant and propellant ingredients will not sustain a burning reaction for the conditions which will exist in CASBL (Figure 2). These tests demonstrated that the existing conveyor sprinkler system is more than adequate to prevent between bays flame propagation in most CASBL locations. 

The limiting oxygen index (LOI) measures the minimum oxygen content that is required to sustain a flame [10]. The specimen in this test is in a vertical orientation, but it is the top of the specimen that is ignited. Because the specimen burns in a candle-like fashion, LOI may not be representative of fire situations. However, LOI does give quantitative information and may be useful for ranking the relative flammability of samples. 

This problem can be circumvented in a fuel-rich approach to catalytic combustion for gas turbines recently proposed. In this method fuel is mixed with air to form a fuel-rich mixture that is reacted over the catalyst to produce both partial and total oxidation products. The reaction products are then mixed with excess air and burned in a homogenous flame. Because the gases exiting the catalyst are fuel-rich, they cannot sustain combustion in the event of a homogenous flame backup. The promise of this method needs to be confirmed in full-scale turbine tests. 

This hquid acetylenic endothermic compound j estimated as 230-270 kj/mol, 2 kJ/g) may be decomposed by mild shock, and when heated under confinement, it decomposes with explosive violence and may detonate. Addition of 20-30 wt% of toluene makes the bromide insensitive in laboratory impact and confinement tests [1] More recently, it was classed as extremely shock-sensitive [2]. It can be ignited by impact derived from the liquid-hammer elfect of accidental pressurisation of the aerated liquid, and will then undergo sustained (monopropellant) burning decomposition. Propargyl bromide, added dropwise to bromine, exploded as it neared the halogen [3]. The chloro analogue is similar, but less readily ignited [4]. 

The second case was first reported in 1998.10 A genetic male-sex infant (chromosome 46 XY), during electrocautery circumcision at the age of 2 months, sustained a burn on the skin of the entire shaft of the penis, and most of the penis eventually became dead tissue and sloughed off. Five months later, the remainder of the penis and the testes were removed, and a decision was made to reassign the boy as a female and to raise the infant as a girl. We will call the girl Anna. 

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