Rationale

Ballot Rationale: The current test method description for Permeance is incomplete, it states: “6.4 Permeance Method (Test method E96/E96M, Procedure B) – A 0.5 mm [20 mils] +/- 10% film shall be used. 6.4.1 Test condition: 23 +/- 2 C {73.4 +/- 3.6 F]. 6.4.2 The test is run in the inverted position with water on contact with the film. 6.4.3 Value is reported in inch-pound and SI units.” Test Method E96 offers this option: X1.1.3 Procedure BW – Inverted Water Method at 73.4°F [23°C] and 50% RH. Adding the “BW” reference supplied proper %RH, and cup geometry. The BW method does not describe the contact of liquid water to the roof coating applicable in this case.