Frequently this tension is 0.25 inches of water column, but can be raised or lowered as the process needs. Isolators have to be periodically leak tested to be certain their integrity and stop escape of your decontamination agent. Leak testing can be done by many procedures together with pressure https://medium.com/@tailinscitech/applications-and-benefits-of-tailin-containment-isolator-for-handling-high-potency-materials-8c66a55dbcf7