Differences between ASTM E331 & ASTM E1105

“I have read both ASTM E 331 and ASTM E 1105 and can’t find any difference between the two test methods. It stands to reason that there is a difference, otherwise why two test methods? Can you please explain the difference between them?”

There are fundamental differences that are revealed in the titles of each standard.
These are identified with italics below:

ASTM E 331 — Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference

ASTM E 1105 — Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform or Cyclic Static Air Pressure Difference

Other differences:

  • The E 331 describes the test specimen being affixed to the air chamber
  • The E 1105 describes the air chamber being affixed to the test specimen
  • The E 1105 is the only water infiltration standard that describes the inspection of operable windows
  • The E 331 (and E 547) mention and have diagrams for testing skylights, the E 1105 does not

Hence the 1105 adding the specification of Installed test specimens, and specimens in the field. Included diagrams show these differences. In short, the 1105 is easier to comply with in the field.

It is difficult to find these and other differences without actually placing the two standards next each other, page by page. There is another very similar test method, ASTM E 547, which only allows for the cyclic air pressure procedure. It is also interesting to note that there are a few AAMA standards that refer to these ASTM standards for most of their procedures and are performed in nearly identical fashion.

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