Reliable assumptions for structural fire design of steel car parks

PurposeThis study aims to analyze and discuss the key design assumptions needed for design of car parks in steel, to highlight the impact that the increased fire loads introduced by modern cars and changes in the fire dynamics have on the design, such as fire spread leading to non-localized fires.Design/methodology/approachIn particular, a reliable fire load density to be used for structural design of car park structures is assessed, based on investigations of the fire loads of modern cars. Based on knowledge of fire load and fire performance of cars, the consequences on the fire safety design of steel structures are presented.FindingsDesign recommendation about fire load density and fire protection of common steel profiles are given. Finally, the proposed design is compared with a design practice that has been applied in many instances for car parks constructed with unprotected steel, and recommendations for a reliable design process are provided.Originality/valueNumerous car park buildings have recently been designed of steel structures without passive or active fire protection. The key assumptions that makes possible such design are local fire scenarios, outdated values of the car fire load and utilization of the ultimate steel strength. This paper identifies the shortcomings of such key assumptions, indicating the need for revisiting the methods and possibly even checking the analyses carried out for some already-built car parks.

Thermal and Fire Characteristics of FRP Composites for Architectural Applications

This paper discusses the main challenges of using fiber reinforced polymers (FRPs) in architectural applications. Architects are showing increased interest in the use of FRPs in modern buildings thanks to FRPs’ ability to allow cost effective realization of unique shapes and flexible aesthetics, while accommodating architectural designs and needs. The long-term durability, weathering resistance, and the exceptional mechanical properties have recently suggested the adoption of FRPs for building façade systems in an increasing number of buildings worldwide. However, some challenges for a wider adoption of FRPs in buildings are represented by the environmental and thermal aspects of their production, as well as their resistance to the expected “fire loads”. This last aspect often raises many concerns, which often require expensive fire tests. In this paper, the results of cone calorimeter tests are compared with software simulations to evaluate the possibility of designing FRPs on the computer as opposed to current design practice that involves iterative use of fire testing. The comparison shows that pyrolysis simulations related to FRPs are still not an effective way to design fire safe FRPs for architectural applications.

Thermal and Fire Characteristics of FRP Composites for Architectural Applications

This paper discusses the main challenges of using fiber reinforced polymers (FRPs) in architectural applications. Architects are showing increased interest in the use of FRPs in modern buildings thanks to FRPs’ ability to allow cost effective realization of unique shapes and flexible aesthetics, while accommodating architectural designs and needs. The long-term durability, weathering resistance, and the exceptional mechanical properties have recently suggested the adoption of FRPs for building façade systems in an increasing number of buildings worldwide. However, some challenges for a wider adoption of FRPs in buildings are represented by the environmental and thermal aspects of their production, as well as their resistance to the expected “fire loads”. This last aspect often raises many concerns, which often require expensive fire tests. In this paper, the results of cone calorimeter tests are compared with software simulations to evaluate the possibility of designing FRPs on the computer as opposed to current design practice that involves iterative use of fire testing. The comparison shows that pyrolysis simulations related to FRPs are still not an effective way to design fire safe FRPs for architectural applications.

Specific Features of Materials Selection for Special Protective Clothing for Metallurgical Industry Employees

The existing technical requirements for protective clothing of the employees of metallurgical enterprises are very general and do not consider the full variety of hazardous factors of industries in this area. Metallurgist special clothing should not only reliably protect against fire and heat exposure, but also provide for comfortable work environment. Methodology and criteria for assessment of the fabric thermal resistance, which are the basis for the requirements of metallurgist protective clothing, do not fully consider the real thermal and fire loads on the material of the protective suits top, that may result in the loss of the physical, mechanical, and protective properties of the fabric, as well as its destruction. It is advisable to develop a more comprehensive approach to the thermal safety requirements, which considers the actual loads on the fabric for selecting the protective clothing material. It is required to ensure not only its fire and heat resistance and integrity of the operational properties, but also comfortable working conditions that allow employees to perform their professional duties more efficiently. Experimental studies were conducted (in laboratory and production conditions) on the assessment of the thermal insulation ability, resistance to ignition, spills, and splashes of the molten metals for the materials recommended by the foreign and Russian companies for the top of metallurgists special clothing. It is shown that the materials made of a mixture of heat-resistant and wool fibers have advantages over other materials. The development of new materials from a mixture of heat-resistant and modified fibers with the improved functional characteristics is one of the promising and necessary areas at the development of suits for the employees in the metallurgical industry. Structural and methodological scheme is proposed that ensures an integrated approach to the development of special protective clothing for the metallurgists. Establishment of the thermal safety requirements in this approach is carried out considering the specifics of the personnel work, real thermal and fire loads on the fabric.

A Comparative Study on the Fire load of Structures by Usage in Korea and Japan

In this Study, to secure data for the fire safety design of buildings, we calculated the fire load of domestic buildings through combustible investigation and based on existing studies. In addition, we classified the use of rooms according to the purpose of building. In addition, we reclassified the survey data and compared it with data from Japan. The comparison showed that the living room fire load was 417.14 (MJ/m²), the bedroom fire loads of buildings except housing were 1,005.9 (MJ/m²), and the fire loads of office facilities and similar facilities were 1,354.8 (MJ/m²). These values are 1.8 to 4.3 times higher than the Japanese standard.

Determining the Impact of High Temperature Fire Conditions on Fibre Cement Boards Using Thermogravimetric Analysis

When exposed to temperatures that are progressively and rapidly raised, large dimension fibre cement boards tend to crack. This occurrence is analysed and explained for a specific issue of asymmetric growth of a curvilinear crack in high temperatures. This phenomenon occurred while performing Single Burning Item (SBI) experiments at fire loads which are higher than those used in countries of the European Union, which better reflect fire events that may occur in high-rise buildings. In such conditions, fibre cement boards crack, allowing the fire to reach the thermal insulating material which then combusts, thereby helping to spread the conflagration to upper floors. This experiment investigated the temperatures at which fibre cement boards crack, and why. Thermal analysis methods and thermogravimetric experiments were conducted on the fibre boards, followed by X-ray phase analysis investigations. During this phase, X-ray structural analysis was performed while the fibre cement was exposed to temperatures of 1000 °C. The article also presents ongoing change results when heating only composite fibre-cement board materials; phase changes that take place in high temperatures are discussed.

Study on Fire Risk Assessment Method by Considering Warehouse Characteristics

Large spaces, such as warehouses where internal loads are stored, exhibit higher fire loads and faster fire growths than general fires. In addition, the volume of the internal load reduces the space required for the smoke to stay, thereby accelerating the decline in smoke height. To prevent fire hazards in such spaces, it is necessary to evaluate the fire risk during the design stage. However, it is difficult to evaluate various settings because the evaluation method using the existing computational fluid dynamics utilize considerable amount of time. In this study, an algorithm was developed to evaluate the internal loads by using formulas related to the existing fire risk assessment. The developed algorithm is designed to easily calculate the detection time of the detector, smoke fall time, and sprinkler operation time. This algorithm could be used to design an optimized fire protection system in the initial design stage.

Study on Flame Spread Characteristics of Flame-Retardant Cables in Mine

Polymer combustion is an important factor in mine fires. Based on the actual environment in a mine tunnel, a cable combustion experiment platform was established to study the regularities of the cable fire spread speed and smoke temperature under different conditions, including various fire loads and ventilation speeds. The flame change and molten dripping behaviour during the fire spread process were also analyzed. The experimental results show that the flame-retardant cable can be ignited and continuously burnt at a certain wind speed, but the combustion can be restrained at high wind speed. The combustion speed of the flame-retardant cable is affected by the fire load and ventilation speed. The combustion droplets can change the shape of the flame, which can consequently ignite other combustible materials. The analysis of the experimental results provides an important basis for the prevention of tunnel fires.

Numerical investigations on post-fire bond behaviour of reinforcement in concrete

Reinforced concrete (RC) structures may be subjected to accidental fire loads during their service life. In such a case, it is essential to have appropriate methods for the estimation of post-fire performance. One of the vital aspects for the performance of RC structures is adequate steel-to-concrete bond. The bond behaviour under ambient conditions is very well established. However, an appropriate model for the assessment of the post-fire bond capacity is still lacking. In order to provide more insight into the bond performance after fire, a 3D FE numerical study using a thermo-mechanical model with temperature dependent microplane model for concrete is performed. The effects of concrete cover, confinement through stirrups, fire duration and exposure type on post-fire bond performance are investigated using beam-end specimen. The results show a strong degradation of post-fire bond capacity, which is primarily attributed to the irreversible damage of concrete cover resulting from heating and cooling.