Fire Test Facility Research Articles

Validating hybrid fire testing with full-physical twin experiments

Real fire incidents show that structural systems have specific fire-induced redundancies that make them perform better than classical structural fire analysis predicts. Properly validated hybrid fire testing has the potential to tap into such redundancies for designs. In this study, we conceived and implemented a comprehensive and novel physics-based validation strategy for hybrid fire testing. We developed a laboratory-scale thermo-mechanical proof-of-concept problem that is representative for structural systems exposed to compartment fires. We solved the proof-of-concept problem using our novel thermo-mechanical hybrid solution procedure (Schulthesset al.2020Comput. Struct.238, 106301 (doi:10.1016/j.compstruc.2020.106301)) and compared the resulting hybrid model response against the results from a full-physical laboratory set-up of the same proof-of-concept problem, which we call a full-physical twin experiment. Full-physical twin experiments constitute the top layer of a suite of benchmark tests any specific hybrid fire testing procedure must pass to qualify not only as theoretically accurate and correctly functioning but also (and more importantly) as physically sound and able to yield realistic simulation results. This paper delivers such a first-of-its-kind physics-based validation, and in doing so, the first comprehensively validated method for hybrid fire testing—a method that now allows fire test facilities to conduct meaningful full-scale hybrid fire tests of entire structural systems.

Experimental testing and evaluation of coating on cables in container fire test facility

Fire tests were conducted on cables using fire-retardant paint employed in nuclear power plants that transmit electrical power, control and instrument signals. The failure criteria of various power and control cables coated with fire retardant coating at three different coating thicknesses (∼0.5 mm, 1.0 mm & 1.5 mm) were studied under direct flame test using Container Fire Test Facility (CFTF) based on standard tests for bare cables. A direct flame fire test was conducted for 10 min with an LPG ribbon burner rated at ten by fixing the cable samples in a vertical cable track. Inner sheath temperature was measured until ambient conditions were achieved by natural convection. The cables are visually evaluated for damage and the mass loss percentage. Cable functionality is ascertained by checking for electrical continuity for each sample. The thickness of cable coating on fire exposure is also studied by comparing the transient variation of inner sheath temperature along the Cable length. This study also evaluated the adequacy of fire-retardant coating on cables used for safety-critical equipment in nuclear power plants.

A computationally rigorous approach to hybrid fire testing

Real fire incidents have shown that the structural systems of high-rise buildings perform much better during a fire attack than what classical structural fire analysis predicts. The reason behind this phenomenon is the empirically established fact that beneficial interaction mechanisms evolve between the fire-exposed and the fire-unexposed parts of structural systems. However, there is no computational method available to reliably quantify such interaction mechanisms for design purposes. Pure numerical methods are too uncertain, because they cannot be validated, and isolated structural member testing does not allow considering the interaction. Hybrid fire testing, however, can precisely fill this fundamental methodological gap when set up as an extended finite-element analysis technique. Here, we provide the first computationally rigorous method for hybrid fire testing. We have validated the novel method with several proof-of-concept tests covering the entire temperature-range relevant for structural fire engineering. In contrast to other approaches, only our method can deal, so far, at the same time suitably, accurately and robustly with the experimental and computational challenges of temperature-dependent material behavior. We therefore place hybrid fire testing on a sound scientific basis enabling existing fire test facilities to do more realistic (hybrid) assessments of the fire performance of structural systems.

VIRGILE project: The concept of virtual fire resistance facility for the assessment of construction products performance

Construction industries products have to satisfy fire safety regulation, including technical approvals in fire resistance, by tests in accredited laboratories. Fire resistance tests lay down on a complex protocol, in which full size samples are settled in large furnaces able to reproduce severe time-dependent fire curves. The full-scale mounting and the cost of such tests could be a constraint for their development. In that context, the concept of virtual facility has been developed by Efectis during the VIRGILE project. The use and development of numerical simulation tools are an interesting complement to the fire tests. The developed tool aims to model a fire resistance test including interaction between sample and fire test facility. The virtual facility allows to better analyze and evaluate a large number of technical alternatives in order to find the most efficient technical and economical solutions. Moreover, numerical simulations may improve the testing conditions including thermal stress control and metrology. This paper presents an overview of the main results and applications achieved during the VIRGILE project in ten years.

The fire resistance of lightweight composite tanks depending on fire protection systems

To save weight and resources lightweight tanks with complex geometries made of glass-fibre reinforced plastics (GFRP) are a promising innovation for the transportation of dangerous goods. To realise the use of polymer tanks for such applications, their fire safety must be guaranteed. This paper presents solutions to protect fibre-reinforced plastic tanks from fire. The fire resistance of six GFRP tanks with different fire protection systems was tested in an outdoor full-scale fire test facility according to the regulation stipulated in the ADR (European agreement concerning the national carriage of dangerous goods by road). All tanks feature a complex geometry and a holding capacity of 1100 litres. The fire protection systems are composed of specialised resins as well as two intumescent coatings. All systems had a protective impact. The best results were achieved by the epoxy based intumescent coating, which was able to prolong the time needed to reach 150 °C inside the tank by 20 min. The emergence of a temperature holding point inside the tank due to condensation effects was observed at temperatures around 100 °C.

Analyzing fire-induced dispersion and detector response in complex enclosures using salt-water modeling

The current investigation examines suitability of the hydraulic analog for analysis of fire-induced dispersion within a complex enclosure. This analog has been implemented using salt-water modeling and planar laser induced fluorescence (PLIF) diagnostics providing quantitative visualization of simulated fire-induced flows. The non-intrusive PLIF diagnostics are used to temporally and spatially characterize dispersion from a buoyant source within a 1/7th scale room–corridor–room enclosure. This configuration is geometrically similar to a full-scale fire test facility, where local fire conditions were characterized near five ionization type smoke detectors placed throughout the enclosure. The full-scale fire and salt-water model results were scaled according to the dimensionless fundamental equations that govern source dispersion.An evaluation of the local conditions and dispersive event times for both the systems was used to explore the ability of the hydraulic analog to predict smoke detector response times. The dispersive event (front arrival) times predicted by the salt-water model, which represents a necessary event for detector activation, were in excellent agreement with the fire test data. A methodology using these front arrival times along with local conditions at the detector location is introduced in this paper. However, the complex nature of detector response and fidelity limitations of the analog make precise predictions of detector response time challenging. The predicted dimensionless response times were within 25% for all detector locations, with the exception of the first-room ceiling detector location. For this latter, a shorter dimensionless response time by less than 40% of that in the actual fire was predicted.

Brand new fire test facilities at ‘BAM Test Site Technical Safety’

AbstractFire testing is an essential part of the hypothetical, cumulative mechanical and thermal accident test conditions that shall guarantee package safety in severe accidents. Not only for radioactive material transport packages but also for other containments of dangerous goods, international standards require specific thermal load specifications. Following the guideline ‘Safety in technology and chemistry’ BAM, as a scientific and technical German federal government institute, operates a 12 km2 large open air test facility for experimental investigations of dangerous goods and their containments. On an area beside the well-known 200-ton drop test facility, BAM has put into operation a new fire test facility. This facility provides two fire test stands that utilise liquid propane as fuel from a central, earth-covered 60 m3 LPG storage tank. From that storage the propane is pumped via pipelines to the test stands where the gas is released from nozzles, and ignited by ignition burners. The fire exposure...

Drop and fire testing of spent fuel and HLW transport casks at ‘BAM Test Site Technical Safety’

BAM, as a competent German government institute for the mechanical and thermal testing of radioactive material transport and storage containers, operates unique drop and fire test facilities for experimental investigations on the open air BAM Test Site Technical Safety. To be able to perform even drop tests with full scale spent fuel or HAW casks (i.e. the German CASTOR cask designs), BAM constructed in 2004 a large drop test facility capable to handle 200 ton test objects, and to drop them onto a steel plate covered unyielding target with a mass of nearly 2600 ton. Drop test campaigns of the 181 ton GNS CONSTOR V/TC, the 129 ton MHI MSF-69BG and a 1∶2 scale model of the GNS CASTOR HAW28M (CASTOR HAW/TB2) have been performed since then. The experimental BAM drop testing activities can be supported also by drop testing of smaller packages (up to 2 ton) in an in-house test facility and by dynamic, guided impact testing of package components and material specimen inside a new drop test machine. In May 2008, ...

Experimental Investigations of Fire Spread and Flashover Time in Office Fires

The characteristics of, prediction models for, and experimental data pertaining to flashover in full-scale room fires were first reviewed. Then, initiation, growth, full development, and decay of three office fire scenarios were experimentally explored using a 10 MW fire test facility and continuous online combustion gas analysis. The conditions for flashover were investigated and compared with correlations in the literature. The model office compartment is an aerated lightweight concrete structure with dimensions of 5 m × 6 m and with a net room height of 2.4—3.3 m. The results show that the measured minimum heat release rate at flashover is consistent with the correlations of Babrauskas [5] and McCaffrey et al. [6]. Based on the fundamental definition of flashover using the ‘energy-filling’ concept it is possible to predict the flashover time via a case-based reasoning method. However, more work is needed to further validate this concept.

A Full-Scale Prototype Multisensor System for Damage Control and Situational Awareness

The U.S. Naval Research Laboratory has developed a real-time, remote detection system for damage control and situational awareness, called “Volume Sensor”, as part of the Advanced Volume Sensor Task, an important element of the U.S. Navy’s Office of Naval Research, Future Naval Capabilities program, Advanced Damage Countermeasures. The objective of the Advanced Volume Sensor Task was to develop an affordable detection system that could identify shipboard damage control conditions and provide real-time threat level information for damage control events (such as flaming and smoldering fires, explosions, pipe ruptures, flooding, and gas releases) while eliminating the false alarms typical of fire detection systems in industrial environments. The approach was to build a multisensor, multicriteria system from low cost commercial-off-the-shelf hardware components integrated with intelligent software and data fusion algorithms. Two multicompartment prototype Volume Sensor systems were constructed at NRL and tested with a series of simulated damage control events at the Navy’s full-scale fire test facility, the ex-USS Shadwell in Mobile Bay, AL. Results from this test series indicate that the Volume Sensor Prototypes performed as well or better than commercial video image detection and point-detection systems in critical quality metrics for fire detection while also providing additional situational awareness for flooding scenarios, fire suppression system activations, and gas release events.

Numerical model and validation experiments of atrium enclosure fire in a new fire test facility

The use of computational fluid dynamics (CFD) as a tool for buildings, warehouses or factories design requirements fulfilling about fire safety is becoming more common and reliable. Performance-based fire safety assurance procedures make use of the CFD fire modelling to anticipate the evolution of fire, but they need always to be validated. This is especially difficult for big structures, with great clear volumes, where effects of natural and forced ventilation can be very scale dependent. A good opportunity to check the prediction capability of CFD codes to establish temperatures and velocities fields is the new full-scale fire test facility of the Technological Metal Centre in Murcia, Spain. It is an aluminium prismatic squared base building of 19.5 m×19.5 m×20 m, with several vents arranged in its walls and four exhaust fans at the roof. Series of experimental tests have been carried out using several heptane normalized pool-fires placed at the centre of the atrium. The data obtained from these experiments have been later used in a validation study of two CFD simulations implemented for temperature wall, ambient temperature prediction and exhaust fan assessment. The results show good agreement between experimental and numerical predictions and allow concluding that for a fire test of 1.6 MW of average heat release power, the exhaust and ventilation system is not enough to extract the hot combustion products. There is an excessive and dangerous accumulation of hot gases at the upper part of the atrium and the exhaust capacity of the roof fans must be increased. The CFD models can give the answer to that question.

Overheating, flame, smoke, and freight movement detection algorithms based on charge-coupled device camera for aircraft cargo hold surveillance

We introduce a new approach to aircraft cargo compartment surveillance. The originality of the approach is in the use of a single sensor type, a CCD camera, to detect fire events and freight movement in aircraft cargo holds (multiphenomenom/monosensor approach). The CCD camera evaluation and the radiometric and geometric models are provided in (Sentenac et al., 2002). We go on to discuss the image analysis algorithms used in the detection of fire signatures (hot spots, flame, and smoke) and load displacement. For each phenomenon, the discriminant parameters are established and the algorithm is explained. The crucial factor is the validation procedure according to aeronautical standards. The experimental trials were carried out in a test chamber providing the fire and smoke test facilities [TF1 to TF6 following EN 54 (Afnor, 1997) requirements].

Fire test facility

Fire test facility

Seal fire test facility opened

Dunlop Aerospace Precision Rubber, manufacturer of elastomer engine and airframe seals, has commissioned an in-house fire testing facility. This is a short news story only. Visit www.worldpumps.com for the latest pump industry news

Radioactive Materials Packaging Test Facility at Gravatom Engineering Systems Ltd, UK

Gravatom Engineering Systems Ltd (GESL) have been involved in the design, manufacture, testing and certification of radioactive materials transport packaging for some 30 years. Over that time they developed a team of engineers and facilities capable of bringing packages into service, ranging from excepted to Type A, at their Bishops Waltham site. Type B(U) packages are also designed and built at Bishops Waltham but there are no water immersion or fire test facilities there. This paper describes the test equipment and the supporting facilities at GESL.

Enclosed Pool Fires In Low Ventilation Enclosures: Flame Temperatures And Global Heat Loss Using Gas Analysis

Enclosed kerosene pool fues were investigated with ventilation equivalent to normal leakage into a room with the doors and windows closed and air in leakage due to gaps around doors and windows. A 1.9 m3 enclosed fire test facility with separate air inlet at floor level and fue product outlet at ceiling level was used. A fully heated gas sample system was used, including unburnt fuel analysis, as total hydrocarbons are required as well as CO to determine the combustion efficiency and the airlfuel ratio by carbon balance. This air /fuel was used to determine the adiabatic mean flame temperature of the fue as a function of time as well as the entrained air mass flow rate. The adiabatic temperature was compared with the measured flame temperature and it was shown that the time to peak temperature was the same. The temperature difference was used to determine the global heat loss to the enclosure walls as a function of time. The peak heat transfer per unit wall surface area was 6 kW/ m' for the highest ventilation rate. The global heat transfer to the enclosure was 70-80% of the heat release at the peak fue intensity for three ventilation air flow rates. NOx concentrations were also determined and the rate of formation of NOx was used to compute the temperature of the hot zone that formed the NOx. This temperature was shown to increase very rapidly after the start of the fue to a maximum of approximately 1500K for all three ventilation rates. The size of this hot zone was taken as a cylinder of vertical height equal to a free pool f r e flame height and diameter. The surface area of this at 1500K was shown to account for the measured global heat transfer.

The Effect of Pool Diameter on the Property of Smoke Produced by Crude Oil Fires

The smoke production from the burning of crude oil was investigated for a 1m diameter pan and for a 2.7m × 2.7m pan, which is the largest pan size used within a fire test facility for smoke characterization. The smoke yield, as measured by two procedures both based on the carbon balance method, increased by about 50% as the pan size increased. Analysis of the smoke by transmission electron microscopy showed that the volume mean diameter of the primary spheres increased by about 80% as the pan size increased. These results are compared with other studies ranging in scale from a pool diameter as small as 8.5cm to as large as 12m crude oil spill fires and 100m pool fires set during the 1991 war in Kuwait.

The effect of pool diameter on the properties of smoke produced by crude oil fires

The smoke production from the burning of crude oil was investigated for a 1-m-diameter pan and for a 2.7×2.7-m pan, which is the largest pan used within a fire test facility for smoke characterization. The smoke yield was measured using the carbon balance method by two different procedures: one involved continuous sampling to gas analysis equipment, and the second used a portable, airborne-smoke-sampling package (ASSP). The advantages and limitations of the carbon balance method are addressed. The smoke yield increased by ca. 50%, from 0.100 to 0148, as the pan size increased. These results are compared with other studies ranging in scale from a pool diameter as small as 8.5 cm to those as large as the 12-m crude oil “spill” fires and the 100-m pool fires set during the 1991 war in Kuwait. Possible causes for the factor-of-5 lower yield measured for the Kuwait oil-well fires, compared to the larger pool fires measured in this study, are examined. The primary sphere size of the smoke was measured by transmission electron microscopy (TEM). It was found that the diameter of the primary spheres increased by ca. 80%, from 58 nm to 106 nm, as the pan size increased. This scale dependence of the primary sphere size is discussed in light of recent studies concerning smoke formation.

Sodium Pool Combustion Codes for Evaluation of Fast Breeder Reactor Safety

For the evaluation of thermal consequences of a sodium leak accident in the auxiliary buildings of the LMFBRs, the sodium pool combustion codes SOFIRE-MII, ASSCOPS and SPM have been developed. In SOFIRE-MII and ASSCOPS, assumptions are made that the combustion occurs at a pool surface, and the process is controlled solely by the turbulent oxygen transfer from atmospheric gas to the pool surface. Combustion heat is dissipated by turbulent and radiation heat transfers to the gas and surrounding walls. On the contrary, a flame over the pool is modeled in SPM, in which the combustion is controlled by sodium vapor and oxygen supplies by the diffusion from the pool surface and the turbulent mass transfer from the atmospheric gas, respectively. These codes were validated using experimental results obtained in the large-scale sodium fire test facilities; SAPFIRE (PNC, Japan) and FAUNA (KfK, Federal Republic of Germany). The comparison revealed that agreements between the codes and the test results are reasonably well.

Heat transmission in fire test furnaces

AbstractThis theoretical and experimental study, complementary to that discussed in Reference 1, examines those factors that affect the ‘test efficiency’ in fire resistance testing. Convective heat transfer in the test chamber may become an essential part of the heat transmission process if, due to small furnace size or non‐luminous furnace gases, the radiative transmission is not sufficiently intense. The standard technique of measuring and controlling the temperature conditions in the furnace chamber, though not in line with strict scienctific practices, appears to provide insurance against poor test result. A calibration procedure is described for checking the adequacy of fire resistance test facilities and some solutions presented for improving the test efficiency.