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 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.     

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 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.     

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.     

Engineering geological and geophysical investigations of a slope failure at Edinburgh Castle, Scotland

Edinburgh Castle is one of Scotlands most important heritage sites. It was built on a classic crag and tail structure where the crag consists of columnar jointed basalt and the tail of sediments protected from glacial erosion by the crag.In 1997 apparent instability was observed on the southern side of the tail. A shallow slope failure was proved to have taken place within saturated, layered, cohesive to non-cohesive, loose to dense heterogeneous fill on a slope of 44°. The date of the initial failure is not known, but is likely to have taken place over a period of many years, since at least the 1950s.Remediation works were subsequently undertaken to stabilise the slope, consisting mainly of the installation of soil nails, a bi-axial geo-grid and minor filling to mitigate the effects of the ground movements and to facilitate repair of the retaining wall.     

Physiological aspects of fire fighting

The conditions and requirements of the fire fighter and the unusual demands of fire fighting activities have received increased attention since the early 1970s. Other industries usually design physical performance requirements around the capabilities of the worker, but the fire fighter must respond to the constraints and requirements of the emergency. Recent research and its relationship to a fire fighter's physical profile are described and discussed. Reference: Paul O. Davis and Charles O. Dotson, Physiological Aspects of Fire Fighting,Fire Technology, Vol. 23, No. 3, November 1987, p. 280–291. Note: This paper is from a paper presented at the III Coloquio Internacional Sobre Equipos de Proteccion Personal, in Mallorca, Spain.     

Limited-water-supply sprinklers for manufactured (mobile) homes

A prototype limited-water-supply (LWS) sprinkler has been developed for manufactured (mobile) homes in a research program sponsored by the United States Fire Administration. The LWS sprinkler is designed to be installed at a 2.44 m (8-foot) spacing and to have a total water supply of 380 (100 gallons). The installation spacing was determined in a series of freeburn fire tests that indicated that the heat release rate at sprinkler actuation could be halved by reducing the sprinkler spacing from 3.66 m to 2.44 m (12 feet to 8 feet). A series of eight fullscale fire tests, including a corner living room scenario similar to that used in the Los Angeles Residential Test Program, was conducted to evaluate the performance of the prototype sprinkler. In five of the tests, room tenability was maintained during the 10-minute period following the actuation of a single sprinkler at a flow rate of 38 pm (10 gpm). In three tests, tenability was maintained with multiple sprinkler actuation (2 or 3 sprinklers) and a total system flow rate of 49 pm (13 gpm). The spray of the sprinkler was characterized in terms of its water flux distribution and drop size distribution. The thermal sensitivity requirements of the sprinkler are to be based upon RTI, C, and temperature rating, which would ensure that sprinkler actuation would occur at fire sizes comparable to those encountered using the prototype LWS sprinkler in this study.     

Sublethal Effects of Fire Smoke

Fire smoke toxicity has been a recurring theme for fire safety professionals for over four decades. There especially continue to be difficulty and controversy in assessing and addressing the contribution of the sublethal effects of smoke in hazard and risk analyses. The Fire Protection Research Foundation (FPRF), the National Institute of Standards and Technology (NIST), and NFPA have begun a private/public fire research initiative, the International Study of the Sublethal Effects of Fire Smoke on Survival and Health (SEFS) to provide scientific information on these effects for public policy makers. The papers in this issue of Fire Technology present results from the first phase of the project: estimates of the magnitude and impact of sublethal exposures to fire smoke on the U.S. population, the best available lethal and incapacitating toxic potency values for the smoke from commercial products, the potential for various sizes of fires to produce smoke yields that could result in sublethal health effects, and state-of-the-art information on the production of the condensed components of smoke from fires and their evolutionary changes during transport from the fire.     

Wood heating safety research: An update

The Center for Fire Research at the National Bureau of Standards has been involved in research related to wood heating safety for more than seven years.Areas of interest have included: typical operating conditions of modern heating appliances, intensity and duration of chimney fires in factory-built and masonry chimneys, clearance reduction systems for protection of combustible walls and ceilings, and wall pass-through systems for connection of appliances to chimneys through combustible walls. This paper presents a review of research at NBS and elsewhere related to wood heating safety and provides an assessment of the impact of the research on the fire safe use of wood heating appliances.Extensive references of research related to solid fuel heating safety are included. Reference: Richard D. Peacock, Wood Heating Safety Research: An Update,Fire Technology, Vol. 23, No. 4, November 1987, pp. 292–312.     

Fire stops for plastic pipe

Undue fire hazards may arise when plastic pipe penetrates fire-rated walls or floors. Fire stops for protecting these penetration openings are available commercially. This paper discusses the physical characteristics and operating modes of these devices. A selected number of fire stops were tested in accordance with CAN 4-S115-M85 in either horizontal (wall) or vertical (floor) configurations, using two small-scale furnaces. Reference: K. K. Choi, Fire Stops for Plastic Pipe,Fire Technology, Vol. 23, No. 4, November 1987, pp. 267–279.     

Some tools for fire model validation

General ideas are offered for describing fire model validity prior to starting product design. Validation of independent test results is part of this phase. Differences between comparable results, graphical methods, and distinctions between random and systematic errors are discussed. Reference: Alan D. Davies, Some Tools for Fire Model Validation,Fire Technology, Vol. 23, No. 2, May 1987, pp. 95–114.     

Fire resistance of wood structures

Wood as a building material has the disadvantage of being combustible. Consequently wood structures are seen by many as creating an environment less safe than structures built of noncombustible materials such as steel and masonry. However, experience has shown that some wooden structures have a fire resistance comparable, or greater than that of many noncombustible alternatives. Some statistical figures are given comparing wood with other materials. The fire course and the burning mechanisms of wood are briefly discussed, as is the fire resistance of wood structures from different perspectives. Reference is also made to present research work. Reference: Kai Odeen, Fire Resistance of Wood Structures,Fire Technology, Vol. 21, No. 1, February 1985, p. 34. Note: This paper is a modified version of a paper presented at the International Fire Protection Engineering Institute in Brunnen, Switzerland in February and March 1984.     

Methods to calculate the response time of heat and smoke detectors installed below large unobstructed ceilings

Recently developed methods to calculate the time required for ceiling mounted heat and smoke detectors to respond to growing fires are reviewed. A computer program that calculates activation times for both fixed temperature and rate of rise heat detectors in response to fires that increase in heat release rate proportionally with the square of time from ignition is given. This program produces nearly equivalent results to the tables published in Appendix C, Guide for Automatic Fire Detector Spacing (NFPA 72E, 1984). A separate method and corresponding program are provided to calculate response time for fires having arbitrary heat release rate histories. This method is based on quasi-steady ceiling layer gas flow assumptions. Assuming a constant proportionality between smoke and heat released from burning materials, a method is described to calculate smoke detector response time, modeling the smoke detector as a low temperature heat detector in either of the two response time models.Nomenclature A g/(c _p T ) - c _p specific heat capacity of ambient air - C _s smoke mass concentration - D effective binary diffusion coefficient - g acceleration of gravity - H vertical distance from fuel to ceiling - I light intensity - I_o initial light intensity - L light beam length - _s smoke gas mass production rate per unit volume - OD optical density per unit length (see Equation 8) - fire energy release rate - energy release rate per unit volume - r radial distance from fire axis to the detector - RTI response time index, the product of the detector thermal time constant and the square root of the gas speed used in the test to measure the time constant.⁹ - t time - t ₂ ^* dimensionless time t/[A^{–1/5 –1/5} H^4/5) - (t ₂ ^* ) _f dimensionless time for time delay for gas front travel - T ambient temperature - T gas temperature at detector location - T _s temperature of detector sensing elements - T T — T - T ₂ ^* dimensionless temperature differences T/[A^2/5(T _f /g) ^2/5 H^–3/5] - U gas speed at the detector location - U ₂ ^* dimensionless gas speed U/[A H]^1/5 - Y _s local ratio of smoke mass to total mass in flow - proportionality constant for t²-fire growth = Q/t² - ambient air density Reference: David D. Evans and David W. Stroup, Methods to Calculate the Response Time of Heat and Smoke Detectors Installed Below Large Unobstructed Ceilings,Fire Technology, Vol. 22, No. 1, February 1985, p. 54. Note: This paper is a contribution of the National Bureau of Standards and is not subject to copyright.     

Collapsed spring observations in arson investigations: A critical metallurgical evaluation

Observation of collapsed coiled (steel) furniture springs has been utilized for several decades or more by arson investigators as an indicator of whether an accelerant or smoldering source (such as a cigarette) caused a fire. This paper cites the contradictory literature, synopsizes metallurgical phenomena operative when coiled steel springs are subjected to fires, and presents empirical data from U.S. Federal Bureau of Investigation (FBI) Laboratory testing. It is concluded that observation of the collapsed state of coiled furniture/bedding springs is not a reliable indicator of whether a fire was initiated by a smoldering cigarette or accelerated by the presence of a hydrocarbon.     

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.     

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.     

Fire resistance tests and differentiated design procedures — The Building Code: Aims and means

Every building should be executed and arranged in such a way or by the use of such materials that, taking into consideration its purpose and location, it will give reasonable fire safety for persons staying in the building, including proper facilities for saving the occupants and for fire extinguishment to be carried out, and also to give reasonable safety against spread of fire to adjoining buildings and activities on adjoining sites. — Danish Building Code, Chapter 6.1.1 Note: The material properties of the compartments are defined in References 3 and 4. A black furnace refers to a furnace in which the incident flux is equal toT _gas ⁴.     

The Florida palm coast fire: An analysis of fire incidence and residence characteristics

A quantitative analysis of the relationship between residential fire incidence, fire intensity, house characteristics, and location is presented. Fire intensity (ground vs. crown fire) was shown to be the most significant factor. Brush clearance and type of soffit vent were also shown to be related to fire incidence. Logit analysis was used to analyze the joint effect of the various factors. Five factors allowed the model to correctly predict whether a house burned in 83 percent of the observations. Reference: Robert Abt, David Kelly, and Mike Kuypers, The Florida Palm Coast Fire: An Analysis of Fire Incidence and Residence Characteristics,Fire Technology, Vol. 23, No. 3, August 1987, pp. 186–197.Florida Agricultural Experiment Station Journal Series No. 8241     

Influence of fire retardants on smoke generation from wood and wood derived materials

The influence of three fire retardant agents: Polichron, Pyrolak W-10, and Pyrolak W-10 + Pyrolak W-1 on smoke density of pine wood, plywood, soft hardboard and tough hardboard was investigated. Surface samples of 25 cm² (5 × 5 cm) were used and the heat flux was varied over the range of 1.0 to 4.0 W/cm². Reference: Tadeusz Cisek and Jacek Piechocki, Influence of Fire Retardants on Smoke Generation from Wood and Wood Derived Materials,Fire Technology, Vol. 21, No. 2, May 1985, p. 122.