# IRC R703.1.1, Exeception 2 ~  ASTM E 331



## codewonk (Sep 16, 2010)

At the risk of tedium, R703.1.1 exception 2 states:

"Compliance with the requirements for a means of drainage, and the requirements of Section R703.2 and Section R703.8, shall not be required for an exterior wall envelope that has been demonstrated to resist wind-driven rain through testing of the exterior wall envelope, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E 331 under the following conditions:" (et al)

Per ASTM's subtitle for  E 331, it is a " Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference."

Finally the question; does the use of this exception require the field use of all of the specific E 331 tested components (i.e., cladding , specific flashing details for joints, penetrations and intersections with dissimilar materials, WRBs, etc. )? In other words, is it the intent of the code that a designer may select a single component out of the test mock-up (i.e., the WRB) and invoke this exception?

I don't believe that is the intent but I would appreciate hearing your take. Thanks !!!


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## pyrguy (Sep 16, 2010)

Not from where I sit. Looks like they want a tested 'system' not just components of a system.

It's kinda like a manufacture saying their complete HVAC system is listed because the motor in the unit is.


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## codewonk (Sep 16, 2010)

That's been my understaning.


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