ASTM D751 Comparison

Breaking Strength - Grab Method

The maximum force required to break a sample of the membrane when pulled in opposite directions.

This is done by cutting a 4 inch x 6 inch (10 cm. x 15 cm.) sample, clamping it in 1 inch (2.5 cm.) jaws and pulling it to break. The results are reported in pounds-force (KiloNewtons) to break.

*All results have been reported in the machine direction (MD) of the fabric.

Test Results

Fibertite®	36 mil	463 LBF (2.1 kN)
NBP	50 mil	485 LBF (2.2 kN)
PVC #1	45 mil	460 LBF (2.0 kN)
TPO #1	45 mil	379 LBF (1.7 kN)
PVC #3	50 mil	349 LBF (1.6 kN)
TPO #2	45 mil	323 LBF (1.4 kN)
CPA	40 mil	309 LBF (1.4 kN)
PVC #2	48 mil	301 LBF (1.3 kN)
PVC #4	48 mil	253 LBF (1.1 kN)

The physical property relates to the ability of a membrane to withstand forces within the roofing environment.

These forces come from wind loads, thermal and/or structural movement pulling on mechanically attached membrane.

Low breaking strength could result in the membrane tearing or breaking away from its attachment.

Test Results according to ASTM Standards as Performed and Reported by Structural Research, Inc.