At an American Society for Testing and Materials (ASTM) meeting last year, the issue of heat aging of TPO single-ply roofing membranes was raised and a tougher test standard proposed.
At an American Society for
Testing and Materials (ASTM) meeting last year, the issue of heat aging of TPO
single-ply roofing membranes was raised and a tougher test standard proposed.
Keep in mind, this occurred long
before the Midwest
Roofing Contractors Association (MRCA) Technical and Research (T & R)
Committee distributed its advisory on TPO roofing systems. This advisory
recommends that MRCA members take special precautions to limit TPO accelerated
weathering due to excessive solar or thermal loading.
Last month, in a letter to Tom Drake, executive director of
MRCA, SPRI Technical Director Mike Ennis said SPRI agrees that special care
must be taken in areas of a roof that may be subjected to temperatures beyond
the in-service limits recommended by materials manufacturers. However, Ennis
added that MRCA did not include data to support its conclusions, and the
advisory unfairly singles out TPO membranes.
While it seems like another controversy is brewing in the low-slope roofing
industry, the end result should benefit roofing contractors, architects and
While we cannot predict the future, it seems probable that the industry’s
three top TPO producers will agree to raise the bar on TPO heat aging
performance. The change will most likely come within ASTM D 6878 Standard Specification for Thermoplastic
Polyolefin Based Sheet Roofing. It is also likely that other TPO
producers besides the “big three” will have to step into line and adhere to the
SPRI and MRCA may rightfully agree to disagree on certain points of the
latter’s advisory bulletin. But, in general, it appears the roofing industry is
working together to improve the performance of TPO roofing membranes. Should
that scenario take place, then everyone will win.
We can also look forward to the introduction of some significantly
enhanced TPO roofing membranes in the coming months.
There will always been differences of opinion in the roofing industry,
but in this case, ASTM, MRCA, SPRI and certain TPO manufacturers all deserve a
round of applause should things pan out as expected.