Fully furnished and finished 3.7 by 5.5-m (12 by 18-ft) rooms, designed to simulate a typical hotel/motel arrangement, were ignited in identical scenarios and allowed to proceed past flashover. The test facility consisted of the burn room attached perpendicular to the end of a 13.7-m (45-ft) corridor with another room off the corridor 4.9 m (16 ft) from the test room. The second room contained animals for an assessment of both preflashover and flashover toxic effects. The rooms and corridor were fully instrumented with thermocouples, heat flux radiometers, smoke meters, gas sampling trains, and, in the burn room only, smoke detectors and sprinkler heads. In the few minutes prior to visual flashover, the toxic hazard of this fire scenario increased dramatically. At the 1.7-m (5 1/2-ft) level in the burn room, temperature rose to 650°C (1200°F), carbon monoxide (CO) concentration reached 70 000 ppm, oxygen concentration dropped to zero, and the hydrogen cyanide level exceeded 1000 ppm. In the remote room, the animals died from carbon monoxide poisoning around 12 min after the dramatic change in conditions (approximately 10 min after visual flashover occurred). Other factors besides CO contributed to the incapacitation of the animals.

Hydrogen chloride decay, defined as the deposition of hydrogen chloride from fire (and other) atmospheres onto surfaces, has been studied as a function of atmospheric humidity, of size or configuration of the apparatus used, of type of surface in the apparatus and of rate of air movement. This decay means that, in a static system with a sorptive surface, hydrogen chloride has a half-life of 3 min or less, before disappearing from the atmosphere. A simplified mechanism has been devised to identify reactions which simulate the processes involved in hydrogen chloride generation, transport and decay. Mathematical fitting of the hydrogen chloride concentration-time profiles obtained from a large-scale and two small-scale apparatuses was carried out. The "parameters" Downloaded from 106 calculated in this way have been used as a method for screening system variables and identifying dependencies.It has been found that several factors affect hydrogen chloride decay, viz.: (i) The presence of humidity in the atmosphere greatly accelerates decay.(ii) The type of surface exposed to hydrogen chloride will have a large effect in determining peak atmospheric concentrations and rates of decay, with sorptive surfaces being responsible for much more rapid decay than smooth surfaces.(iii) The level of air agitation will also influence hydrogen chloride decay, because of the effect on the rate of transport of the molecules to the reactive surfaces.This work has two important implications in terms of fire hazard: (a) The peak airborne concentrations of hydrogen chloride which will be encountered in a real fire scenario will be much lower than would have been predicted from the chlorine content of the fuel; furthermore, these concentrations may soon decrease to very low levels because of decay.(b) The majority of small-scale smoke toxicity tests use non-sorptive surface environments; they are likely, therefore, to exaggerate the toxicity of the combustion products of chlorine-containing materials such as poly(vinyl chloride).

Large-scale combustion product evaluation experiments were carried out in a realistic room-plenum arrangement. A 30 ft. (9.14 m) length of electrical power wire with flexible PVC jacket and insulation was decomposed, in a plenum, by the action of an electrical overload. The combustion gases measured were HCl, CO, CO 2 and unburned hydrocarbons. The maximum concentration of HCl in the plenum was 3000 ppm (which represents roughly one third of the total chlorine in the wire). However, this amount decreased rapidly

Currently, several issues are causing controversy in the review of ASTM fire resistance standards. The predominant issues are the time/ temperature curve, the use of positive pressure, and the use of the hose stream test. These issues are discussed, and an historical background is provided. Recommendations for their resolution are provided. The resolution of these issues will assist in the harmonization of test standards with other standards organizations.