How to calculate the breathing volume of a breather valve on a tank that is under pressure?

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There is a storage tank equipped with compressed air aeration at the bottom, and the waste gas from the top is sent to waste gas treatment systems. The design pressure of the tank is at atmospheric level; it is designed in accordance with standard tank design principles and is fitted with a vent valve and safety manholes. Now the question is: how should the ventilation capacity of this vent valve be calculated? If only the feed and discharge volumes as well as the heat loss due to respiration are considered, this amount is not large; but should the aeration volume be taken into account? The aeration volume is quite high, approaching 1000, which results in a significant difference. But from the perspective of the protection tank, if the downstream fan fails, it is advisable to choose a valve with a small opening size, as this makes it difficult to release pressure in a short period of time; in such cases, it is necessary to activate the safety manhole, which is a reasonable solution. Additionally, the fan is equipped with a bypass system, and when the fan stops operating, the bypass activates to prevent pressure buildup within the system. Has anyone encountered a similar situation before? How was it handled?