Advanced fire research presents useful finding for engineers and steel industry

By Dr Troy Coyle, CEO, HERA

Alongside a University of Auckland researcher, Charles Clifton, structural steel experts at HERA, Fanqin Meng, Nandor Mago, and Kaveh Andisheh, have evaluated the structural fire performance of steel car park frames caused by vehicle fires. They also have numerically validated the reliability and accuracy of a new structural fire design procedure for steel car parks using ABAQUS (software for realistic simulations), that allows engineers to design these structures using more realistic fire scenarios with confidence.

In accordance with the New Zealand design guide, a minimum fire resistance rating (FRR) of 30 or 60 minutes is required for structural components in sprinklered or unsprinklered buildings, respectively. These requirements are based on the assumption of a uniform-burning fire scenario within car park structures. Other research (cited in the paper) has found that in car park structures with well-designed sprinkler systems, a one-vehicle fire is the most likely to happen, especially in Aotearoa New Zealand (A more comprehensive statistical data analysis conducted by Tohir et al in 2014 showed that 86% or 344 out of 401 incidents of vehicle fires were one-vehicle fires).

To evaluate the structural response, two representative vehicle fire scenarios were investigated using Abaqus for car park structures with sprinkler systems. The overall results from the simulated structures demonstrated that although the structural beams experienced plastic deformation in both fire scenarios, none of them reached failure during the simulation.

All this information contributed to the advanced structural design methodology, which is applicable to steel-framed buildings used for car parking with sprinkler systems. The researchers found this methodology might save a certain amount of fire protection materials in construction, which offers the potential for more cost-effective designs of steel-framed car park buildings by reducing essential fire protection material requirements.

Applying this design methodology could improve the accuracy and financial efficiency of car park structural fire design both for new buildings and retrofitted buildings, and might also simplify retrofitting existing car park buildings with sprinkler systems, enhancing fire safety measures.

Meanwhile, reducing fire protection demand will improve the environmental sustainability of buildings by reducing the buildings’ carbon footprint and minimising the use of chemical materials to meet the required fire safety standards.

This paper offers an alternative solution to the current NZ Building Code, and together with other advanced structural fire design methodologies, like SPM (Slab Panel Method) for composite steel floor systems design under severe fires, HERA is actively promoting and facilitating the adoption of these methodologies within the industry by driving awareness, providing guidance, and encouraging the application.

The findings are relevant for engineers and other stakeholders in the construction and property industry, including building investors, government authorities, Standards NZ, and relevant standard committee members. Moreover, it may provide a benchmark for numerically assessing the future impact of electric vehicle fires on car park structures.  To read the research paper, click here.