Pool fires under atmosphere and ventilation in steady-state burning (part I)

Modeling based on Spalding's theory was undertaken to obtain information on a solvent pool fire under atmosphere and ventilation in steady-state burning. The model comprised the modified B-number with burning parameters governing the burning rate of solvent. Mass loss rate and burning rate of solvent from the burning pan were governed by heat conduction through the pan wall for small pans and by turbulent free convective heat transfer for large pans.This paper will be published inFire Technology in two parts. Part II will appear in the August 1987 issue. Reference: Gunji Nishio and Satoru Machida, Pool Fires under Atmosphere and Ventilation in Steady-State Burning, Part I,Fire Technology, Vol. 23, No. 2, May 1987, pp. 146–155.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Fire tests on window assemblies protected by automatic sprinklers

Full-scale fire tests on wired and tempered glazing in steel and aluminum frames are described. These assemblies achieved fire resistance ratings when exposed to a standard fire of 45 min to 2 h. The maximum radiant heat flux transmitted through the glass was reduced by more than 90%. Reference: J. K. Richardson and I. Oleskiewicz, Fire Tests on Window Assemblies Protected by Automatic Sprinklers,Fire Technology, Vol. 23, No. 2, May 1987, pp. 115–132.This paper is a contribution from the Institute for Research in Construction, National Research Council of Canada.     

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.     

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     

The use of Computer fire models in corner burn tests

The reduction of corner burn test data to a smaller number of useful parameters is attempted using an experimentally based calculated flow field and the concept of product yields. This is applied to a range of plastic and natural products, all of which had been tested in our corner burn test facility. Comparison of the experimental results are also made with predictions generated by the OSU Room Fire Model using data taken on the OSU rate of heat release calorimeter as input data. Reference: E. D. Dickens, Jr., and G. F. Smith, The Use of Computer Fire Models in Corner Burn Tests,Fire Technology, Vol. 21, No. 2, May 1985, p. 85. Note: Prepared for the Center for Fire Research 1984 Conference, National Bureau of Standards, October 17–19, 1984.     

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.     

Designing escape routes in buildings

This paper discusses a design method for calculating pedestrian movement developed by Predtechenskii and Milinski and provides an egress model based upon this work for the evacuation of multistory buildings via staircases with regard to real evacuation tests in high rise office buildings. Furthermore, it briefly compares its predictions with regulatory requirements on means of escape. Reference: Ezel Kendik, Designing Escape Routes in Buildings,Fire Technology, Vol. 22, November 1986, p. 272.     

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.     

Investigating the unexposed surface temperature criteria of standard ASTM E119

Information and data were obtained to evaluate the unexposed surface temperature criteria of standard ASTM E119. The investigation consisted of: (1) reviewing literature to obtain information on the development of ASTM E119 and the unexposed surface temperature rise criteria, (2) conducting fire tests to obtain temperature data on slabs with various materials placed on the unexposed surface and (3) conducting ignition tests on these materials to obtain their approximate temperature at ignition. The information and data increased the knowledge concerning the relationship between the unexposed surface temperature rise criteria of ASTM E119 and the ignition temperature of common combustible materials.Winner of the 1985 Harry C. Bigglestone Award for Excellence in Written Communication of Fire Protection Concepts. Reference: Kenneth J. Schwartz and T. T. Lie, Investigating the Unexposed Surface Temperature Criteria of Standard ASTM E119,Fire Technology, Vol. 21, No. 3, August 1985, p. 169.     

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.     

Thermal radiative protection of fire fighters' protective clothing

A method for measuring the thermal radiative protection of actual fire fighters' garments to an incident radiative heat flux of 8.4 kW/m² is described. Typical results obtained with several conventional and prototype garments are presented. These results indicate the time to pain, and second degree burn as well as the pain alarm time. The thermal inertia of the garments is also measured based upon burn exposure time. Differences in physical properties such as garment thickness, total weight and number of layers are examined in order to establish the existence of any correlations.Issued as NRCC 26171. Reference: M. Day and P. Z. Sturgeon, Thermal Radiative Protection of Fire Fighters' Protective Clothing,Fire Technology, Vol. 23, No. 1, February 1987, p. 49.