smoke movement

The report describes measurements of the deposition of large particles from a small scale wind tunnel model of a chemical warehouse fire plume. A common feature of such fires is the discharge of relatively large particles with falling speeds of the order of m s- 1, partly generated by mechanical damage, which can fall out of the fire plume in a different pattern to that of the gases and fine particles. These large particles may also contain toxic components, so it is desirable to know their fallout pattern.

Each year in Canada, building fires cause hundreds of deaths, thousands of injuries and billions of dollars’ worth of property damage. Canada has the second highest fire death rate among 15 industrialized countries. In Canada in 1988, about 72% of fire deaths and 40 percent of fire property losses occurred in small buildings, such as one- and two-family homes, apartment buildings and hotels/ motels. The 1989 fire statistics for Alberta indicate that about 70% of fire deaths and 51 percent of fire property losses occurred in small buildings.3 What can we learn from these numbers?

This Update examines various fire-stopping techniques that meet the intent of the National Building Code of Canada (NBC) with respect to fire resistance and that do not adversely affect the sound isolation of the wall assembly. The information is derived from the results of an industry-sponsored consortium project led by the National Research Council's Institute for Research in Construction (IRC).      

A simple procedure to determine the best locations for the installation of smoke detectors in residential buildings is presented. Consideration is given to both detection of fires and audibility of the alarm.

Ventilating a fire compartment during operational fire fighting procedures may have unpredictable consequences. In some cases the ventilation is advantageous: the hot gases are removed from the fire enclosure, the visibility improves and the enclosure cools down. In some cases the opposite happens: with the accelerated burning rate, more smoke is spread around, and the temperatures rise. The most dramatic consequence is the initiation of a backdraft, where the pyrolyzed gases ignite instantaneously, in the worst case causing a severe explosion.

In recent years, the atrium building has become commonplace. This paper explains the physical concepts of the steady fire, unsteady fire, zone fire model, and the fire plume that are the basis of atrium smoke management. The approach to smoke control design calculation in codes is based on the zone fire model concept. In the zone model, smoke forms an upward-flowing fire plume that reaches the ceiling and is considered to form a perfectly mixed layer under the ceiling of the room of fire origin.

In recent years, approaches to smoke management in atria have been introduced into many codes and engineering guides. This paper presents information that can be used for design analysis of atrium smoke management systems. Various approaches to manage smoke in atria are discussed Often a hot layer of air forms under the ceiling of an atrium, and this hot layer can prevent smoke from reaching the ceiling. A method is discussed for dealing with smoke detection when such a hot air layer prevents smoke from reaching the ceiling.

The potential for using a large eddy simulation (LES) computational fluid dynamics (CFD) model to analyze building indoor air quality (IAQ) and ventilation problems was investigated. The LES model was developed by the Fire Science Division of NIST to simulate the transport of smoke and hot gases during a fire in an enclosure.