Smoke Control in Hospitals

Full scale fire tests have been carried out in order to study the influence of different ventilating principles on the time point of fire detection and the smoke filling of a four-bed room. Using conventional mechanical ventilating systems as smoke exhaust systems the time difference left for evacuation of the fire room can be positively influenced. With the conventional ventilating system operating there is a significant difference between time points of detection of the ionization and optical smoke detectors, for both flaming and smoldering fire. Using the low momentum displacement ventilation this difference is reduced, resulting in possibilities for the ionization smoke detector to be optimized for both flaming and smoldering fires. Reference: Øystein Meland and Eimund Skåret, Smoke Control in Hospitals,Fire Technology, Vol. 22, No. 1, February 1986, p. 33.     

Assessing toxic hazard as it relates to overall fire hazard

A framework is proposed for assessing hazards associated with the spread of smoke and hot gases from fires in buildings, and the current predictive capabilities for each component of that framework are described. Particular attention is given to the significance of the toxicity of the combustion products of a material in relation to its other fire properties. The prediction of the onset of hazardous conditions in a three room residential arrangement with upholstered furniture as the burning object is presented to illustrate the usefulness of the National Bureau of Standards (NBS) smoke transport computer code, a key component of the framework. Reference: Andrew J. Fowell, Assessing Toxic Hazard as It Relates to Overall Fire Hazard,Fire Technology, Vol. 21, No. 3, August 1985, pp. 199.     

Fire protection of flammable work stations in the clean room environment of a microelectronic fabrication facility

An applied engineering program is described which investigates the fire safety of combustible wet stations used within microelectronic clean room fabrication facilities. The main concern involves the impact of a wet bench fire on the clean room environment of the fabrication facility. The effectiveness of the installed fire detection and suppression systems are discussed as well as the additional steps which should be taken in order to insure early detection and suppression of fires within wet benches. Reference: Fred L. Fisher, Robert Brady Williamson, Gary L. Toms and Dennis M. Crinnion, Fire Protection of Flammable Work Stations in the Clean Room Environment of a Microelectronic Fabrication Facility,Fire Technology, Vol. 22, No. 2, May 1986, p. 148.     

Slide rule estimates of Fire Growth

A series of prediction methods has been assembled to provide an analytical basis for estimating fire growth in compartments. Solutions for each prediction method can be made using programmable scientific calculators. Prediction methods are presented for: fire size and growth rates, mass loss rates, radiant heat flux, flame height, radial flame impingement, heat flux to a ceiling, smoke filling of a room, carbon monoxide hazard with smoldering fires, temperature rise in a compartment, ventilation flow rate, flashover occurrence, corridor smoke transfer and filling, smoke concentration, visibility, flame spread rates, and fire burn time.These predictive methods are useful for estimating many of the critical elements related to fire behavior and help provide a better understanding of this complex phenomenon.This report appears as Appendix B inFire Growth in Combat Ships by J. G. Quintiere, H. R. Baum and J. R. Lawson, NBSIR 85-3159. Reference: J. R. Lawson and J. G. Quintiere, Slide Rule Estimates of Fire Growth,Fire Technology, Vol. 21, No. 4, November 1985, p. 267.This paper is a contribution of the National Bureau of Standards and is not subject to copyright.     

Fire drainage system

Present firesafety measures were conceived to deal with hypothetical fires spreading by destruction of successive compartment boundaries. A new firesafety system, referred to as the fire drainage system, is designed to cope with real-world fires spreading mainly by convection. It confines fire and smoke to the room of origin and to a small corridor element adjacent to the room. The system can be designed to operate without the use of water and electric energy. The fundamentals of its design are described and some experimental information is presented. Reference: T. Z. Harmathy and I. Oleszkiewicz, Fire Drainage System,Fire Technology, Vol. 23, No. 1, February 1987, p. 26.This paper is a contribution from the Institute for Research in Construction, National Research Council of Canada.     

Estimating room temperatures from fires along walls and in corners

Determination of temperatures associated with room fires provides a means of assessing an important aspect of fire hazard: the likelihood of the occurrence of flashover. Layer temperatures in excess of 600°C have been associated with the occurrence of flashover. A data correlation has previously been presented to estimate layer temperatures for fires burning in the center of rooms. For fires in corners and along walls, restricted entrainment results in higher layer temperatures than predicted by the previous correlation. Modification factors for the previous correlation are developed to extend its applicability to wall and corner burning geometries. The present analysis suggests that a fire in a corner may cause flashover with only half the heat release rate necessary for a fire burning in the center of a room. Reference: Frederick Mowrer and Robert Williamson, Estimating Room Temperatures from Fires along Walls and in Corners,Fire Technology, Vol. 23, May 1987, pp. 133–145.     

Slide rule estimates of fire growth

In the November 1985 issue ofFire Technology, the authors presented prediction methods for estimating fire growth in compartments. Here they provide an example of the use of those methods. Reference: J. R. Lawson and J. G. Quintiere, Example illustrating Slide Rule Estimates of Fire Growth,Fire Technology, Vol. 22, No. 1, February 1986, p. 45.This paper is a contribution of the National Bureau of Standards and is not subject to copyright.     

Effects of insulation on postflashover room fire

The effects of insulation on postflashover room fires were studied in a series of full scale room burn tests. Results show that the severity of the fire is not influenced by the presence of insulation in the walls. Reference: K. K. Choi, Effects of Insulation on Postflashover Room Fire,Fire Technology, Vol. 23, No. 1, February 1987, p. 19.K. K. Choi is a fellow of the Society of the Plastics Industry of Canada.     

Development and application of a fire station placement model

This paper describes the development and application of a fire station placement model. The model is formulated as a mathematical programming model which locates p sites out of m candidate sites such that some function of the travel times of the first and second arriving fire units is maximized subject to several constraints. Among these constraints are limitations in the maximum allowable travel time to points in a region, requirements that certain sites be included or excluded, and a specification that a given number of existing sites be included.The model uses as an objective function a utility function based on the subjective preferences of fire department officials to travel times of the first and second arriving fire units. A modification of the Teitz and Bart node substitution heuristic is used to find the solution to the model.The model is applied to fire station locational decisions in Albany, NY. The model was run a number of times to provide insights into how some strategic decisions might be made. Reference: Jack M. Reilly and Pitu B. Mirchandani, Development and Application of a Fire Station Placement Model,Fire Technology, Vol. 21, No. 3, August 1985, p. 181.     

ASKBUDJr: A precursor of an expert system for the evaluation of fire hazard

The Center for Fire Research (CFR) has a long-term project to develop expert systems as a technology transfer mechanism. The goal of this project is to develop a computer program which will make an expert estimate of the firesafety of a building based on CFR's deterministic physical models, technical data, and the expert judgment of its staff. The first significant computer program to be developed by this project will be based on the expertise of Harold E. (Bud) Nelson. Thus, it will be called ASKBUD. In this article, the first exploratory steps taken to develop this program are described. Also, the progress made to date, as well as some of the major problems that must be solved, will be discussed. Since the system described in this article is in its infancy, we call it ASKBUDJr. Reference: Richard L. Smith, ASKBUDJr: A Precursor of an Expert System for the Evaluation of Fire Hazard,Fire Technology, Vol. 23, No. 1, February 1987, p. 5. Note: This paper is a contribution of the National Bureau of Standards and is not subject to copyright.     

Toxic Hazard evaluation of plenum cables

Code provisions covering the installation of low voltage cables in plenum spaces above suspended ceilings used for environmental air are reviewed. A calculation procedure which could be used to estimate the potential toxicity of the decomposition products from these cables relative to the toxicity of the compartment fire necessary to decompose the cable insulation is presented. These estimates are used in a four-step procedure for estimating Smoke Toxicity Hazard proposed by the NFPA Toxicity Advisory Committee which is described. Example calculations for some typical cases and a discussion of their limitations are included. Reference: Richard W. Bukowski, Toxic Hazard Evaluation of Plenum Cables,Fire Technology, Vol. 21, No. 4, November 1985, p. 252.This paper is a contribution of the National Bureau of Standards and is not subject to copyright.     

Protecting fire fighters exposed in room fires: Comparison of results of bench scale test for thermal protection and conditions during room flashover

Heat flux conditions measured in seven room fires are discussed. The conditions varied from just below flashover in a sparsely furnished bedroom to flashover and severe postflashover fire in a typically furnished recreation room. These heat flux conditions are compared with the protection level provided by fire fighter turnout coats conforming to NFPA 1971,Protective Clothing for Structural Fire Fighting. This standard requires that the turnout coat or pants assembly must protect the wearer against second degree burns when a heat flux of 84 kW/m² (2 cal/cm².s) is applied to its outside surface for a minimum of 17.5 seconds [thermal protective performance (TPP) of 35]. The results imply that fire fighters have only ten seconds or less to escape under most flashover conditions. However, the turnout coats provide good protection in many other fire situations. Practical definitions for flashover are given, and possible means for making the TPP test more relevant for research and development work are discussed.     

Development and Application of the Fire Brigade Intervention Model

A performance based building code [1] was introduced in Australia in 1996. In order that fire brigades could ensure that their functional role was maintained in the building code, a method of quantifying fire brigade roles was required. In response to this issue, the Australasian Fire Authorities Council (AFAC) formed a Performance Based Fire Engineering Committee. This committee developed a model that determines the time taken by a fire brigade to undertake its activities at a fire scene.The Fire Brigade Intervention Model [2] is an event-based methodology, which quantifies fire brigade responses employed during a structure fire from time of notification through to control and extinguishment. It has been primarily developed for use in fire engineering design in a performance based regulatory environment so that the functional role of a fire brigade can be effectively incorporated into the building design process. It establishes a structured framework necessary to both determine and measure fire brigade activities on a time-line basis. It interacts with the output of other sub-systems, which model such events as fire growth, smoke spread, fire spread, detection and suppression as well as occupant avoidance.This paper describes the Fire Brigade Intervention Model, now available for use by fire brigades and fire engineers. The model has been developed for specific case and site analysis and is applicable to most structural fire scenarios. As the expertise of the local fire brigade will be incorporated inthe input parameters, it is valid for most brigade types, crew sizes and resource limitations.This paper also describes ongoing developments including a training package and computer program.The terms fire brigade and fire department are synonymous.     

Fire detection in computer facilities

A recent fire in a computer center in Canberra, Australia, prompted an investigation of the installed smoke detection system. The opportunity was also taken to evaluate alternate detection equipment in the actual center under operational conditions. One device tested was VESDA, a new highly sensitive smoke detector developed in Australia for clean occupancies such as computer rooms and telephone exchanges. Details of the test program and the effects of high room airflows on all forms of detectors are presented. The effectiveness of VESDA in giving very early warning of fire is demonstrated. Reference: Peter F. Johnson, Fire Detection in Computer Facilities,Fire Technology, Vol. 22, No. 1, February 1986, p. 14. Note: This paper is a modified version of a CIRL Major Report No. 251, 1984, prepared for Department of Housing and Construction, Canberra, Australia.     

Preventing fire in historic buildings: The acceptable risk

The nature of historic buildings is considered from a firesafety viewpoint and some of the concepts of acceptable risk are described. The main approaches to the provision of adequate firesafety are discussed and the use of conventional fire precautions is reviewed briefly in the context of historic buildings.This paper is a revised version of a paper given at a seminar, Preventing Fire in Historic and Older Properties, organized by the Royal Incorporation of Architects in Scotland on April 19, 1988 at Hopetoun House, near Edinburgh.     

Postflashover fires — an overview of the research at the national research council of Canada (NRCC), 1970–1985

The NRCC model of fully developed compartment fires is discussed. Although the mathematics involved is quite simple, it allows a rather comprehensive simulation of the fire process. The model offers an explanation for the findings that ventilation control is related to the pyrolysis mechanism and is not a result of scarcity of air in the fire compartment, and that thermal feedback is of secondary importance in the burning (pyrolysis) of cellulosic fuels. Another feature of the model is the introduction of the normalized heat load concept. The normalized heat load is a scalar quantity that depends on the total heat absorbed by the compartment boundaries during the fire incident, and is practically independent of the temperature history of the fire. A simple explicit formula has been proposed and proved experimentally to describe the normalized heat load for real-world fires with fair accuracy. The normalized heat load concept offers a simple means for converting fire severities into fire resistance requirements, and makes it possible to design buildings for prescribed levels of structural fire safety. The potential of fires to spread by convection and the expected characteristics of fires of noncharring plastics are also discussed. Reference: T. Z. Harmathy, Postflashover Fires—An Overview of the Research at the National Research Council of Canada (NRCC), 1970–1985,Fire Technology, Vol. 22, No. 3, August 1986, p. 210.     

Development of Regulations in the 1990 National Fire Code of Canada on storage of Dangerous Goods

The 1990 edition of the National Fire Code (NFC) of Canada contains new requirements to regulate storage of dangerous goods in buildings. In Canada, dangerous goods are defined by the Transportation of Dangerous Goods Regulations as explosives, compressed gases, flammable liquids, flammable solids, oxidizing substances, poisonous and infectious substances, radioactive materials, corrosive substances, and miscellaneous environmentally dangerous substances. The new Fire Code regulations will apply to storage and handling of these products when they are kept in buildings, where they are no longer under the control of transportation legislation.This paper describes the process by which the Canadian National Fire Code was recently revised to address problems created when fires occur in buildings storing dangerous goods. Problems include the increased hazard to the surrounding community because of toxic smoke, runoff of contaminated fire-fighting water, and delays to normal fire-fighting operations. Key ideas that evolved as part of committee deliberations, such as the rationale for regulating products that were not previously considered to be a fire hazard, are described.     

Directions for improving manual fire suppression using a physically based computer simulation

The Swedish Fire Research Board and the U.S. Federal Emergency Management Agency are sponsoring a project to further the understanding of the basic mechanisms involved, as well as to support the development of standards for and to seek ways of improving the performance of portable fire suppression systems used by fire departments.This paper describes a physically based computer model developed to simulate one aspect of the problem: the manual suppression of postflashover fires. This includes: (1) an overview of the physical basis behind the model; (2) a comparison of model predictions with available experimental data, and (3) an analysis of fire suppression effectiveness using the model.The analysis concludes that, when direct access and extinguishment of the burning fuel is not possible, improved fire control occurs with water sprays having a Rosin-Rammler distribution of droplet sizes with volume-median-drop diameters in the 0.15 to 0.35 mm range. This agrees with available experimental data. It is also shown that fire fighting venting and standoff distance requirements may lead to more severe fires requiring more water for control; although venting and water spray induced air/gas flow also serve to channel hot steam and gases away from the fire fighter adding to his safety. The analysis also shows that allowing higher gas and surface temperatures at fire control through improved fire fighter protective clothing and equipment design reduces water flow rate requirements. Additional experimental work is recommended before all these conclusions are considered definitive. Reference: L. M. Pietrzak and G. A. Johanson, Directions for Improving Manual Fire Suppression Using a Physically Based Computer Simulation,Fire Technology, Vol. 22, No. 3, August, 1986, p. 184.     

Protecting fire fighters exposed in room fires,part 2: Performance of turnout coat materials under actual fire conditions

Seven experimental fires varying in fire load were conducted in a simulated townhouse. Specimens of various current fire fighters turnout coat materials were exposed in the room of fire origin. The time at which conditions would become untenable for the fire fighter due to pain, as well as the time to second degree burn, were calculated. These times ranked the coat specimens in roughly the same order as the Thermal Protection Performance measured according to NFPA 1971–1986, especially if the heat in the room developed rapidly.This paper is a contribution of the National Institute of Standards and Technology (formerly National Bureau of Standards) and is not subject to copyright.     

A smoke-filling simulation model and its engineering applications

A brief presentation of the computer model DSLAY1, which describes the smoke-filling process in a single enclosure, is first given in this paper. Also some computed data of the model are compared with experimental results to show the agreement between theory and experiment. In the latter part of the paper computed results are presented for areas where the model has been used for different fire engineering applications. The main purpose is to show that zone models like DSLAY1 are useful tools to predict the heat and smoke conditions in single enclosures as a result of growing fires. DSLAY1 is an interactive computer program. The user converses with the program via a terminal connected to the computer. The dialogue is governed by commands adapted to the concepts of the user. Reference: Staffan Bengtson and Bengt Hägglund, A Smoke-Filling Simulation Model and Its Engineering Applications,Fire Technology, Vol. 22, No. 2, May 1986, p. 92.