How do you test steel structures for fire?

1 Fire testing methods

There are two main types of fire testing methods for steel structures: standard fire tests and realistic fire tests. Standard fire tests are conducted in laboratories, where the steel specimens are exposed to a controlled fire with a predefined temperature-time curve, such as the ISO 834 curve. The aim of standard fire tests is to measure the fire resistance rating of the steel components, which is the minimum time they can withstand the fire without losing their load-bearing capacity, integrity, and insulation. Realistic fire tests are conducted in real or simulated structures, where the steel specimens are exposed to a more realistic fire scenario, with varying temperatures, ventilation, fuel, and load conditions. The aim of realistic fire tests is to evaluate the actual fire performance of the steel structures, including their thermal and mechanical behavior, failure modes, and interactions with other structural and non-structural elements.

2 Fire testing standards

Various national and international standards regulate the fire testing of steel structures depending on the type of structure, component, and fire scenario. For example, ASTM E119 is a standard test method for fire tests of building construction and materials, while EN 1363 is a standard for fire resistance tests. Additionally, BS 476 is a standard for fire tests on building materials and structures, UL 1709 is a standard for rapid rise fire tests of protection materials for structural steel, and ISO 13784 is a standard for reaction-to-fire tests for sandwich panel building systems. Each of these standards specifies the procedures and criteria for conducting standard fire tests on different elements.

3 Fire protection measures

The main purpose of fire testing steel structures is to determine the appropriate fire protection measures that can enhance their fire resistance and performance. Fire protection measures can be divided into passive and active measures. Passive measures do not require any external action or energy to function, such as applying fire-resistant materials or coatings on the steel surfaces, enclosing the steel components with fire-resistant materials, providing sufficient spacing and insulation between the steel components and combustible materials, and designing the steel components with adequate cross-sectional dimensions, shapes, and connections. Active measures require some external action or energy to function, such as installing fire detection and alarm systems, providing adequate ventilation and smoke extraction systems, implementing fire suppression and extinguishing systems, and developing fire emergency and evacuation plans.

4 Fire testing factors

When testing steel structures for fire, there are several factors that can affect the results and interpretation of the data. These include the type and size of steel specimens, which can influence their thermal and mechanical properties, heat transfer, and failure modes. Additionally, the type and intensity of the fire exposure, as well as the type and level of applied load, can have an effect on stress and strain distribution, deformation, and buckling. The type and condition of fire protection measures can also alter thermal resistance, insulation, and integrity of steel components. Finally, the type and accuracy of measurement and instrumentation devices are important to record temperature, displacement, strain, load, and other parameters.

5 Fire testing benefits

Testing steel structures for fire can provide several benefits for structural engineers, designers, owners, and users. It can improve safety and reliability by ensuring the structure can withstand the fire without collapse or spreading the fire. Moreover, it can enhance performance and durability by reducing damage and deterioration caused by the fire. Additionally, testing steel structures for fire can optimize design and construction by selecting the most suitable fire protection measures, materials, and methods for specific structural and fire conditions. Finally, it can help comply with relevant codes and regulations by meeting minimum fire resistance ratings and performance criteria required by authorities and standards bodies.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?