Barrier Textiles
The fabric passes and the gown fails. Barrier performance is decided at the seam, which is the one thing a fabric test never sees.
— cm H₂O
The lower of fabric and seam — what the gown actually holds
Decision-support only. A negative seam margin means the garment fails at the seam whatever the fabric certificate says — and utilisation above 100% is a failure, not a tight pass. Hydrostatic head is a fluid-pressure test and is not by itself a viral penetration result; barrier classification requires testing to the governing standard on finished garments, seams included.
Surgical Gown Hydrostatic Head & Seam Failure Predictor — free, with the formula and a worked example, at Textile School.