The standard outlines the prescribed methods for testing fire resistance of structural components such as walls, floors, beams, columns, and roofs. It details the required heating and pressure conditions, specimen preparation, and criteria for evaluating load-bearing capacity, insulation, and integrity under fire exposure, ensuring safety and compliance in building construction.
Overview
The standard outlines the prescribed methods for testing fire resistance of structural components such as walls, floors, beams, columns, and roofs. It details the required heating and pressure conditions, specimen preparation, and criteria for evaluating load-bearing capacity, insulation, and integrity under fire exposure, ensuring safety and compliance in building construction.
Audience
Contents
Structure
Frequently Asked
The standard heating follows a defined time-temperature curve simulating fire exposure, with the furnace temperature rising according to specified intervals. During testing, an over-pressure of 10 ± 5 Pa must be maintained throughout the heating period, equivalent to 1.0 ± 0.5 mmH₂O, to prevent leakage of hot gases. For vertical specimens, this pressure is applied over the bottom two-thirds of their height and measured at approximately three-quarters height, while for horizontal specimens, pressure measurement is done 100 mm below the underside. Over-pressure is not mandatory for the initial 10 minutes of testing and can be created by adjusting furnace or unexposed face pressures.
Load-bearing capacity evaluation involves applying the design-equivalent load at least 30 minutes prior to heating, stabilizing deformation and loading equipment. The specimen's materials should reflect mechanical strength close to actual service conditions. Throughout the fire test, the element must sustain the applied load without collapse or loss of function. Failure is declared if the specimen can no longer support the load during heating.
Integrity failure is identified by the appearance of cracks or openings allowing flames or hot gases to pass. Initial integrity failure involves minor breaches recorded during testing, while ultimate integrity failure corresponds to significant damage or specimen collapse. Insulation failure is declared when the temperature rise on the unexposed side exceeds specified limits, typically 140°C above ambient. The fire resistance rating is based on the time until any of these failures occur.
Specimens must be representative of the full-scale structural element, including boundary conditions and supports. Conditioning involves adjusting temperature, moisture content, and mechanical strength to replicate in-service conditions, ensuring moisture equilibrium with the ambient environment. At least 30 minutes before heating, the specimen should be preloaded to induce design-level stresses in critical regions, with repeated loading if necessary to stabilize deformations and equipment.
Thermocouples serve as the primary instruments for temperature measurement, recording both furnace atmosphere and specimen surface/internal temperatures. They use wires with diameters not exceeding 0.7 mm. Placement depends on specimen type: one thermocouple per 1.5 m² for walls/floors, two per meter for beams and columns, with a minimum of five thermocouples per test. Temperature data must follow the standard time-temperature curve specified in the standard.
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