Search results

The purpose of this study is to investigate the influencing factors on the charring behaviour of timber, the char layer and the charring depth in non-standard fires.

This paper summarizes outcomes of tests, investigating the influences on the charring behavior of timber by varying the oxygen content and the gas velocity in the compartment. Results show that charring is depending on the fire compartment temperature, but results show further that at higher oxygen flow, char contraction was observed affecting the protective function of the char layer.

In particular, in the cooling phase, char contraction should be considered which may have a significant impact on performance-based design using non-standard temperature fire curves where the complete fire history including the cooling phase has to be taken into account.

Up to now, some research on non-standard fire exposed timber member has been performed, mainly based on standard fire resistance tests where boundary conditions as gas flow and oxygen content especially in the decay phase are not measured or documented. The approach presented in this paper is the first documented fire tests with timber documenting the data required.

Ongoing international collaborative research clearly demonstrates that the concept of adiabatic surface temperature is a simple single parameter to describe the complex convective and radiative conditions to which the surface of a structural element is exposed during fire. This parameter is a convenient and simple interface between fire and thermal/structural models. This paper presents existing published and new unpublished research for fire/structural engineers so as to contribute to the advancement of the engineering practice of designing structures in fire.

A localized fire is a fire which in a compartment is unlikely to reach flash-over and uniform temperature distribution. Designing for localized fires is generally more difficult than for flash-over compartment fires because of the complexity of the problem. There is also a lack of experimental data. We report here on a full scale test series on a steel column exposed to localized fires. The setup is a 6 meters tall hollow circular column, ϕ = 200 mm with a steel thickness of 10 mm. The unloaded column was hanging centrally above different pool fires. Temperatures of gas and steel were measured by thermocouples, and adiabatic surface temperatures at the steel surface were measured by plate thermometers of various designs. The results are compared with estimates based on Eurocode 1991-1-2 which in all cases studied overestimate the thermal impact for this setup. The input from plate thermometers was used to compute the steel temperatures using finite element methods. Excellent agreement was found if the radiation exchange within the column due to asymmetry of the exposure was taken into account.

This paper aims to investigate the probability of unacceptable consequences from structural fire damage in a typical Scandinavian single-story steel frame building and discusses it in relation to life safety. This paper is a complement to the paper “Life safety in single-story steel frame buildings, Part I – deterministic design” by Sandström (2019) which considers the same design philosophy but with a probabilistic design approach.

The reliability of a single-story steel frame building is investigated by using crude Monte Carlo simulation by including consideration to the fire conditions.

The investigated building does not meet the safety levels as stipulated by EN 1990 for structural fire damage. However, by including consideration to the fire conditions in the compartment, it is shown that the life safety objective is not compromised by the structural fire damage, i.e. the structure remains intact as long as any individuals/firefighters can survive within the fire area compartment.

This paper presents practical application of a conceptual paper presenting a general approach to structural fire safety design and the life safety objective.

This paper aims to discuss fire safety design of single-story, single compartment buildings and evaluates whether time to structural damage is a relevant criterion when lethal fire conditions develop long before any structural fire damage can occur.

The proposed approach is demonstrated in a design case study of a steel truss in a typical Swedish single-story steel frame building.

While not complying with deemed to satisfy fire resistance ratings, it is argued that the proposed design still can fulfill the life safety objective.

This paper presents practical application of a conceptual paper presenting a general approach to structural fire safety design and the life safety objective.

The objective of this article is the illustration of the calculation of natural fires and fire resistance of structural members based on the Eurocodes of two types of special structures, in this case a railway bridge and an airplane hangar. The railway bridge has a width of nearly 70 meters and consists of steel beams and a massive concrete slab that are supported by massive columns and walls and for that reason can be compared to a tunnel. The load-bearing structure of the roof of the hangars is made of steel and is supported by steel columns. The choice of a fire scenario on the safe side is crucial for the design process of the unprotected steel structure.