Seek help: fire separation distance for sewage treatment tanks containing trace amounts of Class A flammable liquids

The liquid is in the wastewater; it won’t catch fire, so it can be designed that way. There is no limit on the fire separation distance, but you should keep an appropriate scale in mind.

Severe doesn’t mean there are no restrictions on fire separation distances. Shigui -- 2018 Provisions: 4.2.8A Accident ponds and rainwater monitoring ponds should be located in the lower areas at the edge of the plant site, and can be arranged together with the sewage treatment facility. The fire protection distance between the accident tank and open flames should be no less than 25 m, and the fire protection distance from elevated flares that may carry flammable liquids should be no less than 60 m. The accident tank is primarily used to collect contaminated fire-fighting water under fire conditions, polluted rainwater, and any leaking flammable liquids. Accident water and rainwater generally flow by gravity through pipelines to the accident water tank and the rainwater monitoring tank; therefore, these tanks should be located at lower points on the edge of the plant site. Accident water as well as rainwater that fails to meet the quality standards must be treated before it can be discharged from the plant. By locating the wastewater treatment facilities in a centralized area, it is possible to reduce the length of pipelines and save energy. Since a fire accident may be accompanied by a leak of flammable liquids, fire separation distances have been specified between the accident pool, open flames, and elevated flares that may carry flammable liquids. Since the accident pool remains empty for long periods of time, no fire separation distance is required from other facilities. 4.2.8B Regional oil-containing wastewater lifting facilities should be located outside the plants and units. The fire separation distance from open flames, important facilities, as well as power distribution and cabinet rooms within the process units should be no less than 15 m, while the fire separation distance from elevated flares that may carry flammable liquids should be no less than 60 m. A regional oily wastewater lifting facility refers to a facility for lifting oily wastewater that is installed collectively for multiple units (or devices); therefore, it should be located outside these units and devices, with fire separation distances from important facilities, open flames, and elevated flares established in accordance with the source of emission. For details, please consult the local emergency management agency