Fire Resistance Rating Research Articles

Quantitative Risk Assessment Methodology for Hydrogen Tank Rupture in a Tunnel Fire

This study presents a methodology of a quantitative risk assessment for the scenario of an onboard hydrogen storage tank rupture and tunnel fire incident. The application of the methodology is demonstrated on a road tunnel. The consequence analysis is carried out for the rupture of a 70 MPa, 62.4-litre hydrogen storage tank in a fire, that has a thermally activated pressure relief device (TPRD) failed or blocked during an incident. Scenarios with two states of charge (SoC) of the tank, i.e., SoC = 99% and SoC = 59%, are investigated. The risks in terms of fatalities per vehicle per year and the cost per incident are assessed. It is found that for the reduction in the risk with the hydrogen-powered vehicle in a road tunnel fire incident to the acceptable level of 10−5 fatality/vehicle/year, the fire-resistance rating (FRR) of the hydrogen storage tank should exceed 84 min. The FRR increase to this level reduces the societal risk to an acceptable level. The increase in the FRR to 91 min reduces the risk in terms of the cost of the incident to GBP 300, following the threshold cost of minor injury published by the UK Health and Safety Executive. The Frequency–Number (F–N) of the fatalities curve is developed to demonstrate the effect of mitigation measures on the risk reduction to socially acceptable levels. The performed sensitivity study confirms that with the broad range of input parameters, including the fire brigade response time, the risk of rupture of standard hydrogen tank-TPRD systems inside the road tunnel is unacceptable. One of the solutions enabling an inherently safer use of hydrogen-powered vehicles in tunnels is the implementation of breakthrough safety technology—the explosion free in a fire self-venting (TPRD-less) tanks.

Improvement of Fire Safety Performance for Nursing Homes by Using Fireproof Curtains with a Water Film System

Nursing home residents often have impaired faculties, which limit their evacuation responses in light of accidents. Specifically, fire accidents can pose significant risks to both residents and property. In this study, we designed a water film cooling system to enhance the heat and smoke resistance of a fire retardant curtain without a fire resistance rating. The experimental results on a full-scale door/wall refractory furnace and smoke-barrier system showed that the proposed curtain had 1.5-h heat resistance properties, while the smoke control performance could meet the ISO 5925-1 requirement. Finally, we used Fire Dynamics Simulator (FDS) 6.0 to simulate an existing nursing home with this type of fireproof curtain setup for horizontal evacuation waiting space. The results show that our proposed water film cooling system can effectively inhibit the diffusion of smoke during the initial stage of a fire, creating a safe evacuation waiting zone for disadvantaged evacuees.

Fire Resistance Rating for Gypsum and Kapok Fiber Composite Materials

Fire rated door is one of the passive fire protection systems that can prevent fire and smoke from spreading when a fire occurs. The purpose of this study was to analyze fire rated doors made of Gypsum and Kapok fiber composites. This fire rated door has been manufactured in accordance with Malaysian Standard MS1073: Part 2: 1996. This fire rated door has been modified with various composite compositions and thicknesses. The results showed that the fire rated door made of Gypsum and Kapok fiber can last from 30 to 60 minutes. This study clearly shows that door thickness is very important in the manufacture of fire rated door.

Performance of Composite Plate Shear Walls/Concrete Filled (C-PSW/CF) Under Fire Loading: A Numerical Investigation

Concrete-Filled Composite Plate Shear Walls (C-PSW/CF), also known as SpeedCore walls, are being increasingly used in commercial buildings due to the benefits of modularization and expedited construction schedules. This paper numerically investigates the behavior of C-PSW/CF subjected to combined gravity and fire loading. 3D non-linear inelastic finite element models of C-PSW/CF were developed and benchmarked to existing experimental data. The benchmarked models were used to understand the thermal and structural behavior of the walls under uniform fire loading, and to evaluate the effect of different parameters on the response of C-PSW/CF to combined gravity and fire loading. The parameters considered in the study were boundary conditions, wall slenderness ratio, wall thickness, axial load ratio, concrete strength, steel plate slenderness, steel reinforcement ratio, and tie bar spacing. Fire loading led to high surface (steel plate) temperatures, the evolution of non-linear thermal gradients through the cross-section, and progressive degradation of the material properties. The walls expanded longitudinally due to the thermal loads. The degradation in material properties resulted in local buckling of the steel plates between the tie bars. Continued fire exposure led to crushing/global instability failure of walls under gravity loads. The time to failure of the walls reduced considerably with a reduction in rotational fixity at the boundary conditions, reduction in wall thickness, and an increase in the wall slenderness. The steel plate slenderness of the walls should be limited to 1.2√Es/Fy to improve the time to failure of the walls. The results from this study will form a basis for the development of recommendations to estimate the fire-resistance rating and the compressive strength of the walls at elevated temperatures.

Review of the NRC Canada Studies on Fire Resistance of Walls: Results, Research Gaps and Design Guidelines

The National research council Canada conducted three major fire resistance studies on the interior party walls, interior fire separation walls and exterior walls. The fire resistance results of these studies were published over the past three decades and the publications were short in suggesting design guidelines for practioners’ use and gaps for future research. This paper summaries the fire resistance results of 35 full-scale wall tests, suggests design guidelines and identifies future research gaps for interior party walls, interior fire separation walls and exterior walls. The result summary includes the effect of different design parameters on the fire resistance performance of wall assemblies such as the stud type and spacing, number of stud rows, number of gypsum board layers and thickness, mid-height blocking, resilient channels installation and spacing, screws spacing for attaching gypsum board to either wall faming or resilient channels, insulation type and exterior wall sheathing type on the fire resistance of loadbearing and non-loadbearing wall assemblies. The summary results was used as the basis for suggesting design guidelines for practioners’ use and identifying gaps for future research to improve the fire resistance performance of wall assemblies. For example, the use of a reduced screw spacing from 406 mm o.c. to 203 mm o.c. in the gypsum board field and from 406 mm o.c. to 150 mm o.c. at the board joints was suggested for future research to keep the protective gypsum board layer attached to studs or resilient channels longer for a better fire resistance performance of wall assemblies. Also, fire resistance design guidelines are suggested, for examples, the use of rock fibre insulation for non-load bearing interior party walls to achieve 1.5-h fire resistance, the use of cellulose fibre insulation for loadbearing fire separation walls to achieve 2-h fire resistance rating and the use of reduced screw spacing in attaching the gypsum board to wall framing from 406 mm o.c. to 203 mm o.c. for loadbearing exterior wall assembly with gypsum board glass mat sheathing to expand the fire resistance rating from non-useful 30-min to a useful code compliance 45-min fire resistance rating assembly. Additional suggested examples for future research gaps and design guidelines are also provided.

Experimental research on fire behavior of L-shaped CFST columns under axial compression

Six L-shaped concrete-filled steel tubular (LCFST) stubs were designed and tested under the axial compression and ISO-834 standard for fire. The temperature distribution, axial deformation development, fire resistance, and failure modes of LCFST columns under fire were investigated. The fire test results show that the fire resistance of the specimen decreases with the increasing axial compression ratio and increases linearly with the thickness of the fire protection layer; and the tension-bar stiffened column has slightly higher fire resistance than multi-cell columns. The fire behavior of LCFST columns was then analyzed using the finite element program ABAQUS and the simulated temperature distributions and fire resistances were found to be in good agreement with the test results. Moreover, the LCFT column has slightly higher fire resistance than the square CFST column specified in the design code GB50936–2014. The parametric analysis results show that slenderness ratio, column limb thickness, eccentricity ratio, and fire protection layer thickness all affect the fire resistance of LCFST columns. It was discovered that the first level fire-resistance rating of LCFST columns could be achieved by adopting a reasonably thick fire protection layer. Lastly, simplified formulas for the fire resistance and fire protection layer are proposed, which can reduce the fire protection layer thickness by 50% compared to the current fire design requirements for CFST columns.

A numerical investigation of 3D structural behaviour for steel-composite structures under various travelling fire scenarios

In performance-based structural fire engineering, “travelling fires” is being gradually accepted as an important fire boundary condition. However, its application is still limited by uncertainties in the selection of different design travelling fire parameters, resulting from the lack of relevant experimental data and corresponding validated structural finite element models which can be used with advanced travelling fire methodologies, e.g. the Extended Travelling Fire Methodology (ETFM) framework. This paper aims to fill this gap through modelling a prototype steel-composite floor structure (representing a “slice” of a large open-plan office), to investigate its true structural response under a wide range of travelling fire scenarios, with an emphasis on considering the effect of concrete slab in a 3D finite element model, using LS-DYNA. To ensure the credibility of this numerical study, the model was first validated against the experimental data of the structural response from the Veselí Travelling Fire Test. In the parametric studies, 32 cases were examined to investigate the thermal and structural response, related to the selection of key design parameters for travelling fires (i.e. fire spread rates, fuel load densities and inverse opening factors (IOF)); fire protection (i.e. different fire protection schemes and required fire resistance rating (FRR)), and the effect of slab specification (i.e. thicknesses and steel reinforcements).It was found that solely satisfying the critical temperature and deflection criteria for the structural members might not guarantee a sufficient structural design for travelling fire scenarios, and it is suggested that the steel stress utilisation should also be examined. Compared with the IOF, it appears that the selection of fire spread rates and fuel load densities are likely to be more critical in identifying the worst travelling fire scenario for the structural response with fire protection. Moreover, the global structural response under travelling fire is also affected by the combination of fire protection (i.e. equivalent FRR in this paper) and fire spread rate. Under a “slow” travelling fire (e.g. 0.5 mm/s) with increasing FRR, the failure of structural elements during the cooling phase was prevented effectively; however, under a relatively “fast” travelling fire (e.g. 2.5 mm/s, 12.5 mm/s), increasing FRR may not always improve the fire performance of the structure. This work also indicates that steel reinforcement ratio has a greater influence on structural response than slab thickness under travelling fires. Furthermore, the 3D finite element model is very important for structural fire analysis, not only due to the more conservative internal force captured by the 3D model (i.e. reduced by over 80 % on the 2D model in our case) thereby reproducing the collapse triggered by the failure of the connection under fire in general, but also the 3D model was able to better represent the deflection and the “internal force reversal” caused by travelling fires.

An Investigation into the Effect of Different Standard Instructions on the Fire Resistance Rating of Intumescent Coated Steel Sections

Many building members such as walls, columns, floor contains various components and materials that should be designed to meet their legal obligations outlined in the building regulations especially for fire safety requirements. The performance of those materials under fire-exposure conditions is of major importance in securing safe constructions. To evaluate the conformity of these structural elements, it is necessary to determine the fire-resistance rating as specified according to a wide range of European, American and other test standards. A comparative study was conducted between NFPA 251 and EN 13381-8 to investigate the contribution of the difference in standard specification conditions in affecting the measured fire rating time. For this purpose, six steel columns (of IPE 360 designation) were coated with intumescent paint at the same dry film thickness (DFT) to evaluate the fire resistance rating considering the conditions that listed in both NFPA 251 and EN13381-8. The results showed that the furnace time temperature curves for both standards were functionally equivalent since the standard deviations don’t exceed 5%. Variations in the fire ratings (representing 9% up to 20% of the test time) attributed to the increased temperature sensing locations which provide comparable readings with lesser deviations/ scattering.

Structural fire design of load-bearing cold-formed steel assemblies from a prototype metal building

This paper describes a procedure to complete the structural fire design of cold-formed steel structures and applies it to column assemblies taken from a prototype one-story metal building designed following U.S. building codes. The fire design procedure includes the definition of performance objectives, design fires, heat transfer analyses by the finite element method, and structural analyses using both the Direct Strength Method and finite element modeling. The results show that the design by analysis achieves the required performance while enabling flexibility and efficiency in design. Thermal analyses provide steel temperatures consistent with prescriptive fire ratings and are also used to demonstrate adequacy of unrated assemblies such as protected double C-shaped sections. The finite element model confirms the applicability of the Direct Strength Method with appropriate retention factors to evaluate the elevated temperature response. The cold-formed steel columns maintain stability well beyond their prescriptive rating owing to the low applied load resulting from the ASCE/SEI 7 load combination in the fire situation, which does not include wind. Therefore, for structures which are lightly loaded in the fire situation, such as these metal building columns, analysis methods can be used to demonstrate superior performance compared to the applied fire resistance rating.

CFD-based framework for fire risk assessment of contiguous wood-frame villages in the western Hunan region

Fire hazards are a serious danger to human life and property safety. Fire accidents occur frequently in wood-frame villages in western Hunan due to their remote mountainous location, low fire-resistance rating of dwellings, and weak fire awareness of residents, resulting in numerous casualties and huge economic losses. This study investigated the fire risk of these villages in terms of village layout, street layout, residential materials, structural forms, energy patterns, and fire habits. A risk assessment framework was proposed to evaluate the fire risk of wood-frame contiguous villages in western Hunan. The fire dynamic simulator and SketchUp modelling software were used to visualise and analyse the fire combustion in single residences and residential clusters to propose fire-risk mitigation strategies. The simulation results can be used to optimise the protection of wood-frame continuous village dwellings. The proposed framework can contribute to the fire safety retrofitting of traditional wood-frame dwellings and fire performance enhancement of new dwellings to minimise human casualties and property damage.

Large-Scale Fire Tests on Sliding Doors for Building Applications

The performance of fire doors is essential for the fire safety in buildings. In the present study, a series of large-scale fire tests on sliding doors is performed in the facilities of the Danish Institute of Fire and Security Technology. The test specimens comprise typical and commercially available door solutions for building applications. Similar doors of approximate dimensions 3 m × 3 m and 5 m × 3 m (width × height) are examined, while separate tests are conducted for each side of door exposed to fire. In all cases, the test specimens are mounted on appropriate wall frames of aeriated concrete as used in practice. The test results are compared in terms of transient temperature and deflection measurements. Findings reveal that the examined sliding doors exhibit satisfactory fire performance meeting the classification requirements. The overall fire performance is not affected by the width opening of door, while the fire resistance rating is significantly influenced by the side of exposure to fire. Finally, the failure characteristics are discussed, and the fire behavior of sliding doors is evaluated.

Study on fire performance of T-shaped concrete-filled steel tubular stubs under axial compression

Six T-shaped concrete-filled steel tubular (TCFST) stubs under axial compression loading were designed and tested under the ISO-834 standard fire curve. The temperature field distribution, axial deformation development, fire resistance and failure mode of TCFST columns under fire were investigated. The fire test results showed that the fire resistance decreases with the increase of axial compression ratio; the fire resistance of the tension bar stiffener column is 18% higher than that of the multi-cell column (the fire resistance values are 89 min and 73 min respectively); the fire resistance of specimens increases linearly with the thickness of the fire protection layer. Then the fire behavior of TCFST columns is analyzed by the ABAQUS software. The simulated temperature distribution and fire resistance are in good agreement with the test results. Meanwhile, the fire resistance is slightly higher than that of the square CFST column in the standard ‘Technical Code for Concrete Filled Steel Tubular Structures (GB50936-2014)’. Furthermore, a parametric analysis results show that slenderness ratio, column limb thickness, eccentricity ratio and fire protection layer thickness have influences on the fire resistance. It is found that the first level fire-resistance rating of TCFST columns can be achieved by adopting a reasonable thickness of the fire protection layer. At last, simplified formulas of the fire resistance and the fire protection layer are proposed, and the simplified formula can reduce up to 50% of the thickness of the fire protection layer compared to current fire design requirements for CFST columns.

Test Methods for Characterizing the Properties of Fiber-Reinforced Polymer Composites at Elevated Temperatures.

Recent research trends focus on developing bio-based (derived from agricultural byproducts) fiber-reinforced polymer (FRP) composites for structural applications. Fire resistance is one of the key issues that need to be addressed for the use of these FRP materials in buildings. The thermal and mechanical properties of the constituent materials essentially determine the fire performance (and the fire resistance rating) of a structural member, and these properties vary with temperature. Further, the properties of composite materials such as the FRP are highly influenced by the composition and type of fibers and matrix, and these thermo-mechanical properties also vary significantly with temperature. Due to this variation, the fire resistance of FRP materials (both conventional and bio-based) poses a major concern for use in buildings. Currently, very few standardized test procedures are available for evaluating the high-temperature material properties of FRP composites. In this paper, a review of testing protocols and procedures for undertaking tests on FRP materials at various elevated temperatures for evaluating their properties is carried out. Recommendations are provided on the most suitable test methods, specimen conditions, testing regime, and other issues associated with testing at elevated temperatures. In addition, the applicability of the proposed test methods is illustrated through a case study on conventional FRP specimens. Further, the applicability of the recommended test procedures for measuring high-temperature properties of bio-based FRP composites is highlighted.

Comparison of Simple and Advanced Methods of Analysis in the AISC Specification for Fire-Resistant Structural Design

AISC Specification Appendix 4 provides criteria to aid structural engineers in structural design for fire conditions. It includes an advanced method of analysis and a simple method of analysis. The simple method provides straightforward equations to determine member capacities at elevated temperatures. However, determination of demands on the structure (forces and deformations) due to elevated temperatures is less clear. This paper aims to minimize these gaps in knowledge. A comparison of these methods will be articulated through the analysis of a 10-story office building. The building is a steel structure with perimeter moment frames and a composite floor system that was designed for hazards in Chicago, Illinois. In order to conduct the advanced analyses, a three-dimensional (3D) finite element method building model was developed using ABAQUS. This model can simulate inelastic deformations, instability failures, connection damage at elevated temperatures, and the effect of temperature on strength and stiffness of materials. The simple analyses were conducted using SAP2000, a commercially available structural analysis and design software. A comparison of results from each method of analysis shows that for gravity framing members, the advanced method produced the longest fire-resistance rating. The fire-resistance rating determined from the simple method was more conservative, resulting in a shorter resistance rating. The simple method was also found to be the most conservative approach for the moment-resisting frame members, making it a less desirable method for designing the lateral system for fire than the prescriptive approach. Use of the simple method may be most advantageous for gravity framing applications only and may be overly conservative for considerations of the lateral framing system.

Огнестойкость железобетонных колонн с конструктивной огнезащитой

PURPOSE. One of the significant requirements for buildings and constructions is providing fire safety, which includes standardization of building structures fire resistance. The experience in applying thin-walled elements has shown high efficiency, technological and operational advantages. Bearing significant power loads, reinforced concrete columns often have low fire resistance (R30... R60), which poses certain risks in case of fire and limits their application in construction industry. To increase structures fire resistance, structural fire retardance is applied. The purpose of this work is to set the fire resistance limits of reinforced concrete columns protected by non-combustible Knauf Fireboard gypsum slabs of various thicknesses on a steel frame and obtain the generalized tabular data based on this research. METHODS. Model fire tests of spun reinforced concrete columns with structural fire retardance have been carried out, as well as simulation of heating a series of hollow and solid section reinforced concrete columns with structural fire retardance in ANSYS finite element analysis system. FINDINGS. Experimental data have been obtained on heating spun reinforced concrete columns of an annular section with an external diameter of 560 mm with a wall thickness of 55 mm and a protective concrete layer thickness of 20 mm for longitudinal reinforcement (12 mm diameter) protected by non-combustible Knauf Fireboard gypsum slabs with 12.5 mm, 20 mm and 40 mm thickness on a steel frame, and unprotected ones (without applying a power load). ANSYS finite element analysis system design models have been developed and the heating of a series of spun annular sections and vibration-compacted solid sections of reinforced concrete columns protected by structural fire retardance have been simulated. For these structures, fire resistance ratings have been calculated at a load-bearing capacity utilization factor of 0.7. Based on a certain array of values of fire resistance limits of reinforced concrete columns, tabular data have been obtained to assess the fire resistance of these structures with structural fire retardance. RESEARCH APPLICATION FIELD. The obtained results can be applied by design bureaus, state fire supervision authorities and state construction expertise in assessing fire resistance ratings of reinforced concrete spun columns of annular section and vibration-compacted solid section protected by structural fire retardance as well as in selecting parameters for these structures that provide specified fire resistance rating without carrying out a series of time-consuming calculations. CONCLUSIONS. Fire tests combined with simulation in ANSYS finite element analysis system make it possible to carry out a lot of calculations and obtain tabular data on assessing fire resistance of reinforced concrete columns with structural fire retardance which significantly reduces labor costs at designing building structures.

Numerical Simulation and Thermophysical Feature Analysis of Fire Propagation Law in Large Urban Rail Transit Buildings

As the development of urban rail transit (URT) picks up speed, more and more attention has been paid to the safety hazards that threaten URT operations. In URT buildings with different fire resistance ratings, the combustion performance and fire resistance limit of their components must meet relevant national standards. It is of certain practical significance to explore the fire propagation law in large modern URT buildings. Considering the peculiarity of URT building fire, this paper carries out numerical simulation and thermophysical feature analysis of fire propagation law. Firstly, the fire propagation features in underground station and section (USS) of URT system were described, and the corresponding control equations were established for mass, momentum, and energy. Then, the factors affecting the attenuation coefficient, including heat exchange coefficient, convection coefficient, and radiation coefficient, were analyzed, and a prediction model was established for temperature attenuation. Experiments were carried out to verify the scientific nature of our numerical simulation of fire propagation law in URT buildings, and obtain the thermophysical properties of fire propagation in URT buildings.

Improving fire resistance and energy performance of fast buildings made of hollow polypropylene blocks

Polypropylene (PP) lightweight blocks have been recently developed for fast, easy and affordable way of residential and administrative building constructions. Although; PP blocks are characterized by many competitive advantages over traditional brick masonry, they lack of fire resistance owing to their low melting temperature. Therefore this study presents a technical cost-effective solution for improving the fire resistance rating (FRR) of the exposed PP walls to meet the requirements of the international building and international fire codes for providing optimal fire protection for occupants. A fire protective cladding system consists mainly of cold-formed steel framing lined with gypsum plasterboards with cavity insulation has been proposed to attain adequate FRR of exposed PP walls. Fire resistance standard test has been conducted on a representative test assembly to evaluate the FRR of the new composite wall. The contribution of the newly developed cladding to the energy consumption performance of a PP building model as compared to the traditional bricks/blocks has been assessed by using DesignBuilder energy simulation software. FRR of an hour (1-h) has been attained based on verifying structural integrity and thermal insulation of the protected PP wall. Up to an hour of fire exposure, the maximum temperature recorded for the unexposed PP wall surface was 69 °C this confirm the enhanced thermal insulation of the composite wall. The utilization of PP blocks in buildings has reduced the annual energy consumption by about 13 and 33.6% as compared to conventional clay and cement bricks respectively. The cladding system has provided additional considerable reduction in the energy consumption rate of PP blocks.

Thermal and structural behavior of cold-formed steel frame wall under fire condition

Light gauge Steel Frame (LSF) system, are extensively used in residential, commercial and industrial buildings. Its growing popularity in building construction industry is due to several advantages over other construction materials such as light weight, high strength and stiffness, uniform quality, ease of prefabrication and mass production, economy in transportation and handling. Fire safety of cold-formed steel structures has become more important since cold-formed thin-walled steel sections heat up quickly under fire condition (high section factor and high thermal conductivity) and present low fire resistance. LSF wall systems are used as primary load bearing structural members providing strength and stability in multi-story LSF buildings. Therefore a better understanding of the fire performance of LSF wall systems is required. The structural behavior of the LSF walls at high temperatures depends on the temperature distribution at the wall component and the mechanical property of cold-formed steel and other materials used in LSF walls at elevated temperatures. Also, the thermal performance of the LSF wall is influenced by its components, including the stud cross-section, stud size, sheathing, and insulation types and their thicknesses, and thermal properties of them. In this paper, a numerical study was undertaken using the finite element program ABAQUS. The structural finite element analysis were conducted under transient state condition using the time–temperature profiles of wall components obtained from the thermal analysis. The finite element thermal and structural models were first validated by comparing their results with the previous test results and then a parametric study was conducted with considering the effect of various parameters such as type of sheathing and its arrangement, stud web depth, stud flange width, and stud cross-section shape. The temperature distribution and time–temperature profile of the wall component and Fire-Resistance Rating (FRR) of the wall have been calculated. The results showed that sheathing is one of the most critical factors in fire resistance of walls and has a significant influence on the FRR of walls and increasing the stud depth affects the thermal and structural behavior of the LSF wall and leads to an increase in the FRR of the wall against fire. Also, increasing the stud flange width of LSF wall does not affect the thermal behavior and temperature distribution of the wall, but leads to an increase in the FRR of the wall against fire. The stud cross-section shape does not affect the temperature distribution in the cross-section but can affect the wall’s behavior under fire conditions.

Experimental investigation on fire resistance of sandwich composite walls with truss connectors

The sandwich composite wall with truss connectors is a new type of double-steel-plate composite wall, which consists of two external steel plates, square steel tubes at both ends, and in-fill concrete. The external steel plates are constrained by the steel trusses, thereby possessing superior mechanical performance. In order to study the fire resistance of the sandwich composite wall, 4 full-scaled walls were tested under one-side ISO-834 standard fire, aiming to investigate the effects of axial compression ratio, truss spacing to thickness ratio, and steel plate thickness on the fire resistance of the walls. The temperature, axial displacement and transverse displacement of key parts of the walls were measured. Experimental results indicate that, the walls could maintain sufficient load-bearing capacity as specified by the Class I fire resistance rating of Chinese Code. The fire endurance of the wall was controlled by its thermal insulation. The deformation pattern of the walls under the fire was overall deflection toward the unexposed surface, and the steel plate exposed to the fire experienced obvious local buckling. The axial compression ratio and the truss spacing to thickness ratio had great effects on the deformation behavior of the walls. When the axial compression ratio was reduced from 0.5 to 0.3, the axial deformation of the wall was changed from compression-predominant to expansion-predominant deformation. A larger truss spacing to thickness ratio led to more obvious buckling of the steel plate exposed to the fire. It is recommended to restrict the truss spacing to thickness ratio of the wall in engineering design.

Study on hazards from high-pressure on-board type III hydrogen tank in fire scenario: Consequences and response behaviours

Exploration of thermal performances of composite high-pressure hydrogen storage tank under fire exposure were critical issues to reduce the risk of tank rupture. Three bonfire tests of type III tanks of 210 L-35 MPa with full compressed hydrogen were exposed to a pool fire to study the response behaviours in fire scenarios. Detailed data on the tank wall temperature and inner pressure were presented in this work. Prototype bonfire tests for the type III tank indicated the failure pressure limits amounted to 41.1–41.8 MPa (average 41.4 MPa). Two consequences (rupture and hydrogen blowdown) will be caused when the inner pressure beyond this limits in fire scenario. The loading-bearing capacity of the tank reduced nearly 3 times under the prescribed fire condition when compared to its average burst pressure of 123.5 MPa conducted from the hydraulic burst test. Results also shown that fire resistance rating (FRR, time to rupture) of the three tanks were 784, 666, and 596, respectively. The FRR got shorter when the tank was exposed in the engulfing fire in advance at hydrogen blowdown case.