Burning duration

The salts of Na, Ba and Sr, used as oxidants and to impart appropriate flame colors, are w soluble. Excessive moisture content (over 0.5%) is deleterious in terms of light intensity, color saturation and burning duration. BlkPdr, a widely used ignition source and flame transfer agent, absorbs moisture and deteriorates rapidly. Many instances of pyrot no-fire incidents have been found to be the result of such deterioration (Refs 10,18,21 38)... 

Ignition sources of BS 5852 Parts 1 and 2 Theoretical heat of combustion approx. Flame height Flame temp. Local heat flux. Rate of burning Duration of flaming ... 

The figures on each curve in the following diagrams show the burning durations (Fig.151-156) or the light intensity (Fig. 157, 158) at 1 atm. 

Pump-probe absorption experiments on the femtosecond time scale generally fall into two effective types, depending on the duration and spectral width of the pump pulse. If tlie pump spectrum is significantly narrower in width than the electronic absorption line shape, transient hole-burning spectroscopy [101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112 and 113] can be perfomied. The second type of experiment, dynamic absorption spectroscopy [57, 114. 115. 116. 117. 118. 119. 120. 121 and 122], can be perfomied if the pump and probe pulses are short compared to tlie period of the vibrational modes that are coupled to the electronic transition. 

In extreme eases irritant ehemieals ean have a eoiTosive aetion. Corrosive substanees ean also attaek living tissue (e.g. to eause skin uleeration and, in severe eases, ehemieal burns with degradation of bioehemieals and ehan ing), kill eells and possibly predispose to seeondary baeterial invasion. Thus whilst aeute irritation is a loeal and reversible response, eorrosion is iiTeversible eell destruetion at the site of the eontaet. The outeome is influeneedby the nature of the eompound, the eoneentration, duration of exposure, the pH (see Figure 5.1) and also, to some extent, by individual suseeptibility ete. Tims dilute mineral aeids may be irritant whereas at higher eoneentrations they may eause eoirosion. 

Explosion is burning that takes place sonically, hence, a shock front is produced. The damage mechanisms are physical destruction from the shock wave, collateral damage from falling structures, and human bums. Suffocation and poisoning are not usually associated with an explosion because of its short duration. A chemical explosives such as nitroglycerine, trinitrotoluene, dynamite, and others were discussed in Section 7.2.6. 

FIRE SIMULATOR predicts the effects of fire growth in a 1-room, 2-vent compartment with sprinkler and detector. It predicts temperature and smoke properties (Oj/CO/COj concentrations and optical densities), heat transfer through room walls and ceilings, sprinkler/heat and smoke detector activation time, heating history of sprinkler/heat detector links, smoke detector response, sprinkler activation, ceiling jet temperature and velocity history (at specified radius from the flre i, sprinkler suppression rate of fire, time to flashover, post-flashover burning rates and duration, doors and windows which open and close, forced ventilation, post-flashover ventilation-limited combustion, lower flammability limit, smoke emissivity, and generation rates of CO/CO, pro iri i post-flashover. 

The only model ever published in the literature is poor. The fact, for instance, that burning speed is taken as proportional to wind speed implies that, under calm atmospheric conditions, burning velocities become improbably small, and flash-fire duration proportionately long. The effect of view factors, which change continuously during flame propagation, requires a numerical approach. 

TABLE 6.7. Relationship of Death from Radiation Burns to Radiation Level and Duration... 

One of the most stringent and most widely accepted test is UL 94 that concerns electrical devices. This test, which involves burning a specimen, is the one used for most flame-retardant plastics. In this test the best rating is UL 94 V-0, which identifies a flame with a duration of 0 to 5 s, an afterglow of 0 to 25 s, and the presence of no flaming drips to ignite a sample of dry, absorbent cotton located below the specimen. Tlie ratings go from V-0, V-l, V-2, and V-5 to HB, based on specific specimen thicknesses. 

Another consideration is the time duration of the thrust, or burn time of the motor. The burn time required is determined by the particular mission,... 

After the tape mask removal the exudate is cleaned by sterile saline. Spot peeling and retaping may be done if the skin looks underpeeled, particularly in areas with severe wrinkling. It is usually accompanied by a short-duration burning sensation. The tape is left for an additional 4-6 h and then removed by the patient. We cover the face with bismuth subgalate antiseptic powder for 7 days (Fig. 8.10). Other options include occlusive moisturizers, antibiotic ointments, and biosynthetic occlusive dressings such as Meshed Omiderm. 

In extreme cases irritant chemicals can have a corrosive action. Corrosive substances can attack and weaken materials of construction, as mentioned in Chapter 3. They can also attack living tissue (e.g. to cause skin ulceration and in severe cases chemical burns), kill cells and possibly predispose to secondary bacterial invasion. Thus while acute irritation is a local and reversible response, corrosion is irreversible destruction at the site of the contact. The outcome is influenced by the nature of the compound, the concentration, duration of exposure, the pH (see Figure 4.1) etc. Thus dilute mineral acids may be irritant whereas at higher concentrations they may cause corrosion. 

After reviewing the results of the trial burn, U.S. EPA will modify the permit conditions again, as necessary, to ensure that the operating conditions of the incinerator are sufficient to ensure compliance with incinerator standards and protection of human health and the environment. Owners/ operators of incinerators must comply with the final permit conditions for the duration of the permit, or until the permit is modified. 

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