Tech Today

Concerns with field uplift testing

NRCA recently learned of at least one insurance carrier and several consultants who are beginning to mandate field testing of newly installed low-slope membrane roof systems in hurricane-prone regions in an attempt to verify in-place wind-uplift resistances. I briefly will review the recognized field test methods, explain their limitations and share NRCA's opinion of this type of quality-assurance testing.

ASTM E907/FM 1-52

There are two recognized field test methods for determining uplift resistances of membrane roof systems: ASTM E907, "Standard Test Method for Field Testing Uplift Resistance of Adhered Membrane Roofing Systems," and FM Global Property Loss Prevention Data Sheet 1-52, "Field Uplift Testing."

Both test methods are largely similar and provide for affixing a 5- by 5-foot dome-shaped chamber to the top side of a roof surface and applying a defined negative pressure to the roof surface inside the dome using a vacuum. During the tests, membrane surface deflection is measured and visually monitored to determine whether the membrane passes or fails.