Fire safety objectives for buildings

Rapidly expanding interest in performance-based codes has created increased attention to the objectives of fire safety. One of the more circumspect yet cogent discourses on this subject was presented by Professor David Rasbash, retired Head of the Department of Fire Safety Engineering at the University of Edinburgh. The following is excerpted from a lecture given to The Incorporated Association of Architects and Surveyors at Morecambe, October 1977, with permission of the author.—The Editor     

The use of nets as barriers for retaining high expansion foam

Is it necessary to totally flood a large undivided structure with high expansion foam for fires involving a small area? In Great Britain, it was suggested that net curtains could be used to subdivide large areas in times of fire. Tests of the foam-retaining capabilities of four types of netting are reported here.     

A modular approach to the subject of fire safety engineering

It is suggested that the subject matter of fire safety engineering be divided into twelve sections. This follows some six years of experience of running an MSc course in the subject. Most of the sections would consist of two parts, a basic part and a more advanced part, and each of these would comprise a module in the subject. It is suggested that most of the basic modules should be common knowledge for all fire safety engineers but a more restricted selection of the advanced modules would be needed for the various specialists in the subject. Ways in which university degrees and other qualifications may be put together using this modular approach are outlined.     

Quantification of smoke produced at fires. Test methods for smoke and methods of expressing smoke evolution

A limited review of the methods available for measuring smoke from burning materials has been carried out in order to define a method that could provide data for calculating smoke load. Results available in the literature have been expressed on a common basis and augmented by further experimental work carried out with a furnace similar to the National Bureau of Standards test furnace and a smoke-containment volume (13.4m³) closer to that used by the Fire Research Station test. Encouraging agreement between the data have been found for methods which allow smoke to become diluted and to accumulate. Agreement could be improved if an allowance was made for flaming being extinguished at different times in a test, dependent on thermal stress and oxygen concentration, even when a pilot light is present. To help express the results clearly, a new unit for smokiness is proposed—the obscura (ob) defined as 1 ob=1 dB light attenuation per metre of light path. The smoke-producing potential of different materials (D_o) is then expressed in units of obscura—cubic metres per gram of volatiles produced during the fire condition (ob m³ g ^?1).