Fire separation distance between fire pump room and Category A and B warehouses

This question is indeed quite interesting. I understand your confusion - the same flammable liquids, xylene and styrene seem to have similar hazards, but the standard requirements for the distance between Class A warehouses and Class B warehouses and fire pump rooms are three times different. Personal understanding of this gap is mainly based on two core logics: Different explosion risk levels: The flash point of Class A substances is <28°C, and the lower explosion limit is <10%. It is easy to reach the explosion limit at room temperature. The fire pump room is a key facility for fire extinguishing. If it is located in an explosion hazard area, it may be blown up first during a fire and lose its ability to extinguish fires. Therefore, Class A warehouses need to maintain a larger safety distance (30 meters) to ensure that the explosion shock wave will not directly destroy the pump room. Although Class B substances are dangerous to a certain extent, their lower explosion limits are usually higher and their flash points are also higher, making them less likely to form explosive gas mixtures at room temperature. The 10-meter spacing has taken into account the effects of radiant heat and flying fire, as well as the cost of project land. The 30 meters specified in the fine chemical industry standard is actually a conservative value, and may also take into account factors such as warehouse volume and storage capacity. Of course, this is just speculation based on normative logic. Experts should also refer to accident statistics and simulation experiments when writing specific provisions. It is recommended that you read the provisions of GB 51283-2020, or search for a comparative analysis of "Petrochemical Regulations GB 50016" and "Fine Chemical Regulations GB 51283". Many veteran engineers from design institutes have written summaries in this regard. If there are specific cases for a certain type of substance, you can also post them for discussion. After all, the critical determination of "Category A" and "Category B" in actual engineering sometimes requires more detailed analysis.

This post was last edited by shijia on 2026-6-12 17:10. This post was not found in the explanation of the provisions of Table 4.2.9 of GB51283. The flash point of styrene is also not high, 31°C. Category B and A.