Stephen Olenick - Academia.edu (original) (raw)

Papers by Stephen Olenick

Fire Technology, Jun 28, 2023

Fire and Materials, 2005

This paper examines the standards for fire safety in transport systems and in particular the test... more This paper examines the standards for fire safety in transport systems and in particular the test method for the flammability of materials within passenger compartments of motor vehicles. The paper compares data from ignition tests conducted in the Cone Calorimeter and the FIST apparatus with tests conducted using the FMVSS 302 horizontal flame spread apparatus. Ten materials were selected as representative of those used as seat coverings of private and commercial passenger vehicles. The time to ignition of new and used materials subject to exposure heat fluxes between 20 kW/m 2 and 40 kW/m 2 was measured. The results from the ignition tests were analyzed using thermally thick and thermally thin theoretical models. The critical heat flux for sustained piloted ignition was determined from the time to ignition data using the thermally thin approach. Derived ignition temperatures from both the thermally thick and thermally thin methods were compared with measurements using a thermocouple attached to the back surface of materials in selected tests. The flame spread rates in the FMVSS 302 apparatus were determined and a comparison was made between the performance of the materials in the flame spread apparatus, the Cone Calorimeter and the FIST. The results suggests that a critical heat flux criterion could be used to provide an equivalent pass/fail performance requirement to that specified by the horizontal flame spread test although further testing is needed to support this.

Fire Technology, Feb 14, 2008

A statistical study was conducted to compare the performance of different residential smoke detec... more A statistical study was conducted to compare the performance of different residential smoke detector technologies when exposed to different fire types. In order to facilitate comparisons between different fire and smoke growth rates, a non-dimensional smoke detector activation relative time was employed. Data from four major experimental studies was analyzed utilizing the relative time approach. The Common Language Effect Size, a measure of the probability that a particular detector technology will be the first to detect a fire of a particular type, was used to assess detector performance. The analysis confirmed previous results that ionization detectors, on average, respond faster to flaming fires, and that photoelectric detectors, on average, respond faster to smoldering fires. More importantly, this study also determined that the responses of ionization, photoelectric, and combination technologies are statistically equivalent for any given future residential fire That is, it cannot be determined with confidence which detector technology will alarm first to the next fire. Additionally, the analysis found that this statistical equivalence between detector technologies has not changed in the last 35 years despite increased fire growth rates associated with changes in furniture materials over that same time span.

Spill Science & Technology Bulletin, Aug 1, 2003

The burning rate of a slick of oil on a water bed is characterized by three distinct processes, i... more The burning rate of a slick of oil on a water bed is characterized by three distinct processes, ignition, flame spread and burning rate. Although all three processes are important, ignition and burning rate are critical. The former, because it defines the potential to burn and the latter because of the inherent possibility of boilover. Burning rate is calculated by a simple expression derived from a onedimensional heat conduction equation. Heat feedback from the flame to the surface is assumed to be a constant fraction of the total energy released by the combustion reaction. The constant fraction (χ) is named the burning efficiency and represents an important tool in assessing the potential of in-situ burning as a countermeasure to an oil-spill. By matching the characteristic thermal penetration length scale for the fuel/water system and an equivalent single layer system, a combined thermal diffusivity can be calculated and used to obtain an analytical solution for the burning rate. Theoretical expressions were correlated with crude oil and heating oil, for a number of pool diameters and initial fuel layer thickness. Experiments were also conducted with emulsified and weathered crude oil. The simple analytical expression describes well the effects of pool diameter and initial fuel layer thickness permitting a better observation of the effects of weathering, emulsification and net heat feedback to the fuel surface. Experiments showed that only a small fraction of the heat released by the flame is retained by the fuel layer and water bed (of the order of 1%). Ignition has been studied to provide a tool that will serve to assess a fuels ease to ignite under conditions that are representative of oil spills. Two different

Experiments have been performed in microgravity and normal gravity to determine the effects of lo... more Experiments have been performed in microgravity and normal gravity to determine the effects of low-velocity airflows on the piloted ignition delay of solid fuels. Natural convection prevents material testing at the low oxidizer velocities encountered in space facilities (∼0.1 m/s); thus, it is necessary to conduct these tests in reduced gravity. Tests have been conducted with two types of fuels, polymethylmethacrylate (PMMA) and a polypropylene/glass fiber composite, aboard the NASA KC-135 aircraft, under air velocities below those induced by natural convection. The short reduced gravity period (∼25 s) provided by the aircraft limits the testing to high external fluxes (∼30 kW/m 2 ) so that the ignition delay times are shorter than the microgravity time. In normal gravity, the ignition delay and critical heat flux for ignition decrease as the forced-flow velocity decreases, until they reach minimum values that are limited by natural convection. The microgravity data indicate that ignition delay is further reduced as the air velocity is lowered. A theoretical model is used to predict the ignition delay for PMMA at low flow velocities in microgravity. The model predicts that the critical heat flux for ignition at the flow conditions expected in space facilities could be as much as half the value measured in normal gravity. The results are important because they imply that, in space facilities, ignition may occur more easily than in normal gravity. If the results are confirmed by long-term microgravity testing, they may have important implications for the fire safety design of space facilities.

Journal of Fire Protection Engineering, May 1, 2003

In 1992, a comprehensive survey of computer models for fire and smoke was conducted at the reques... more In 1992, a comprehensive survey of computer models for fire and smoke was conducted at the request of the Forum for International Cooperation on Fire Research. This study serves as an update to that work. One hundred sixty eight computer modeling programs for fire and smoke from several countries were identified and categorized. The developers were contacted and given an opportunity to supply information about their particular model via an electronic survey. The results of the survey will be made available on the internet at www.firemodelsurvey. com. A discussion of the categories of computer fire models is included, followed by lists of the identified models.

Fire Safety Science, 2003

This is a study into the ability of the Fire Dynamics Simulator-Version 1.0 (FDS 1.0) to predict ... more This is a study into the ability of the Fire Dynamics Simulator-Version 1.0 (FDS 1.0) to predict smoke detector activation. FDS is a field computer model that has shown promise in the modeling of fire phenomena. Two methods were used to create a first order approximation of the ability of FDS to predict smoke detector activation. First, the fluid transport model of smoke within FDS was tested and compared with full scale UL217 test data. Second, a series of full-scale multicompartment fire tests were conducted to provide a data set to further validate the results obtained from FDS. It was determined that FDS can predict smoke detector activation when used in conjunction with smoke detector lag correlations that correct for the time delay associated with smoke having to penetrate the detector housing. Recently, the emergence of computational fluid dynamics (CFD) fire modeling codes based on the RANS (Reynolds Averaged Navier-Stokes equations) has shown promising results when modeling fire induced flow. Exponential growth in computational clock speed has allowed the engineer with a desktop personal computer to define grids with hundreds of thousands of cells that bring approximation of fire phenomena to higher levels of accuracy. Another emerging technology, and the most promising for capturing large-scale transient flow, is the development of the Large Eddy Simulation (LES) technique for fire modeling. The Fire Dynamics Simulator (FDS version 1.0) is the most widely used LES

Fire Technology, Jan 29, 2010

Suppression and Detection Research and Applications Conference (SUPDET) in Orlando, Florida to ad... more Suppression and Detection Research and Applications Conference (SUPDET) in Orlando, Florida to advance the current state of suppression and detection through presentations by leaders in the fields. Nineteen papers on suppression and eighteen papers on detection were presented and discussed among the audience. The entire program of the conference including all of the submitted papers is available at the Foundation's website (www.nfpa.org/Foundation). The following four papers constitute some of the most interesting detection presentations from the SUPDET 2008 conference. The papers were invited for inclusion in this special issue. The papers were expanded and peer-reviewed to meet the requirements of this journal. They cover a wide range of topics and demonstrate the breadth of ongoing research in the field of detection. Also of interest is the international flavor of these papers which include works of research from the United States, Canada, United Kingdom, and Australia. The first addresses experimental work from the United States on smoke detection for ceilings containing deep beams, and has findings applicable to code development as well as computer modeling of smoke flows and smoke deposition on surfaces. The second discusses a considerable project on the detection of fires in tunnels which examined existing detection equipment for tunnels and included both computer modeling as well as experiments in both the United States and Canada. The third discusses the ability of installed fire protection detection and sensing devices in a building to aid firefighting efforts and includes experimental and modeling results of the Dalmarnock testing in the United Kingdom. The final paper was the keynote address from the detection section of the conference and outlines much of the cutting edge research in the last ten years at Victoria University in Australia on the very pertinent topic of awakening sleeping occupants. These papers demonstrate that the international fire detection community is actively researching, through both computer modeling and experimentation, many diverse aspects of fire detection including notification and awakening, sensor-aided firefighting, and detector siting in unique geometries. Hopefully, the fire detection research community will continue to pursue and develop these topics as well as other fire detection-related topics that have practical application and result in better fire safety for the public.

Fire Technology, 2021

Vehicle fires in parking structures developing into large conflagrations are rare but can result ... more Vehicle fires in parking structures developing into large conflagrations are rare but can result in severe economic losses. It is important to understand the hazard posed by modern vehicle fires to determine whether current fire codes for parking garages are mandating adequate fire protection requirements. There has been an increase in the fire hazard from changes in vehicle design and increased use of plastics and other combustible materials in vehicle construction, along with denser parking of vehicles in parking structures. This manifests as faster flame spread within the vehicle, easier ignition and more rapid fire spread to neighboring vehicles. Based on the findings, test data from vehicles older than 2000-2005 model years should not be used as basis for development of codes and regulations. Open parking structures emerge as the main area of concern regarding fires in modern vehicles. The lack of any requirements for active protection systems in the fire codes, and trends in vehicle and garage design suggest that large, devastating fires in these structures could become increasingly common. The spread of fire between vehicles, especially from the initial to the second and third vehicles, is critical in determining the extent of the fire and the ability of the fire department to successfully control and extinguish. Future research should be conducted into earlier detection, sprinkler protection, and fire spread between vehicles to address the hazard.

On a spacecraft, one of the greatest fears during a mission is the outbreak of a fire. Since spac... more On a spacecraft, one of the greatest fears during a mission is the outbreak of a fire. Since spacecraft are enclosed spaces and depend highly on technical electronics, a small fire could cause a large amount of damage. NASA uses upward flame spread as a "worst case scenario" evaluation for materials and the Heat and Visible Smoke Release Rates Test to assess the damage potential of a fire. Details of these tests and the protocols followed are provided by the "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion" document. As pointed by Ohlemiller and Villa, the upward flame spread test does not address the effect of external radiation on ignition and spread. External radiation, as that coming from an overheated electrical component, is a plausible fire scenario in a space facility and could result in a reversal of the flammability rankings derived from the upward flame spread test...

Fire Technology, 2004

The occurrence of a liquid fuel burning on carpet has been involved in many incendiary and accide... more The occurrence of a liquid fuel burning on carpet has been involved in many incendiary and accidental fires. While the research on a liquid fuel fire on carpet is still limited, much work on porous media has been performed using sand or glass beads soaked with liquid fuel. In this study, a heat and mass transfer theory was first developed to analyze the burning process of liquid on carpet, and then several small-scale tests were performed to validate the theory. This analysis is valid for pool fires intermediate in size (5-20 cm. in diameter). The experimental apparatus consisted of a circular pan (105mm) and a load cell. Varying amounts of fuels (heptane, kerosene and methanol) were spilled onto the carpet, which was allowed to burn in a quiescent environment. It was found that due to the different controlling mechanisms, the liquid burning rate could be less or more than that of a similarly spilled free-burning pool fire. For the worst-case scenario in fires, the maximum enhancement of the burning rate due to the porous media is predictable through the physical properties of the fuel. This analysis is valid for both combustion and evaporation. Several similar results in the scientific literature are analyzed to further describe the trend. This work explains the role of carpet in liquid pool fires and also helps to explain special risks related to the presence of carpet involved in arsons and will be useful in reconstruction of the early development of an incendiary or accidental fire.

This study chronicles the development and integration of a smoke detector activation algorithm th... more This study chronicles the development and integration of a smoke detector activation algorithm that describes the response time of a smoke detector into a Large Eddy Simulation (LES) fire model. Although the activation algorithm could be used with any CFD smoke movement model, the results here address specifically its application to the Fire Dynamics Simulator (FDS). The fire model predicts the smoke concentration and velocity adjacent to the detector while an algorithm based on characteristic velocity-based lag times describes the transport of smoke into the sensing chamber of the smoke detector. An Underwriters Laboratories Standard 217 fire test, as well as experimental data from two experimental multi-room compartment fires, were used for comparison and validation of the accuracy of the algorithm. A series of benchmark studies in a numerical wind tunnel provided a mechanism to establish the sensitivity of the model to the different input parameters. The algorithm was found to be...