Installation of flame arresters on the vent holes of internal floating roof storage tanks
Thread Content
According to clause 5.1.9 d) of SH3007-2014, a flame arrester shall be installed at the central vent on the roof of internal floating roof storage tanks. It is understood that this provision is intended for safety and fire prevention reasons, but why are no flame arresters required for the circumferential ventilation openings as well? I hope the experts here can answer my questions!
The circumferential and central vent holes of internal floating roof tanks serve to provide ventilation in the space above the floating deck and up to the fixed roof; these vent holes are not in communication with the liquid surface. However, during actual operation, oil and gas will still enter the space above the floating pad, but their concentration generally does not reach an explosive level. Flame arrestors cause fluid pressure losses; installing them can affect the evaporation of oil and gas, thereby creating an environment in which these substances may reach an explosive concentration. Taking the above two points into account, flame arresters are not installed on the vent holes of internal floating roof storage tanks. The central vent of the storage tank is located at the highest point of the tank, and it is also at risk of fire or other accidents caused by lightning strikes; therefore, a flame arrester is required to be installed on the central vent.