If the fire resistance rating of the fireproof coating is specified as 2 hours, is it still necessary to conduct further calculations?

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To conclude first: if the required fire resistance rating for the design of a component is 2 hours, even if the fireproof coating has a performance rating of 2 hours, calculations are still needed to determine whether this requirement is met. This is because the conditions of the components in the structure you have designed (component parameters, load levels, stress characteristics, etc.) may not be consistent with the test conditions specified in the fireproof coating test report. The fire resistance limit of fireproof coatings is primarily determined in accordance with the standard \"Fireproof Coatings for Steel Structures\" GB14907-2018. The relevant test condition descriptions can be found in the 6.5 Fire Resistance section. Section: HN400x200 (section modulus 161)/36b I-beam (section modulus 126), exposed to fire on three sides, span greater than 4m. Load: A uniformly distributed load simulating a four-point concentrated load is applied, with the total load amount corresponding to 60% of the design bending moment limit (calculated in accordance with Clause 4.1 of GB50017-2003, and overall stability requirements must also be met). It can be seen that the test subject is a simply supported beam under bending, exposed to fire on three sides, with the applied load being only 0.6 of its bearing capacity. The cross-section of the components in the actual structure is not necessarily that cross-section (which means the shape coefficient of the cross-section differs, resulting in different temperature increases of the components over the same period of time) ； Not necessarily in bending (may be in compression/tension) ； If bent, the stress ratio may exceed 0.6.