Building Wall Assemblies: Focus on Testing for Water Leakage and the Role for Sealants and Adhesives

Posted on 3/29/2013 10:59:03 AM By Bob Braun

In my last blog, I focused on a long standing and very useful laboratory test used to measure water penetration: ASTM E331-00(2009) Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference . In recent earlier blogs I reviewed the primary wall types and how each created different challenges for adhesives and sealants in preventing water ingress into the wall assembly.  I also detailed the value of assembly testing which evaluates the complex details in real building walls versus material testing that evaluates a specific property without linkage to the wall geometry and the different substrate conditions in the wall.   We also looked at how sealants and adhesives provide air leakage resistance and how the air leakage is related to water ingress as well. 

This blog will focus on an often employed test related to ASTM E331 which I had reviewed in Blog #23.  Designated ASTM E547, this test was developed in the late 1990’s versus E331 developed in the late1960’s.  However, unlike E331 the E547 test attempts to simulate more real life exposure by cycling the pressure across the test specimen as the test procedure progresses.  See the summary for E547 in this link: ASTM E547-00(2009) Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Cyclic Static Air Pressure Difference .

The E547 test, like E331, provides the details of the instrumentation (similar to ASTM E283) to create a pressure difference across a multitude of building assemblies during the calibrated water spray (minimum rate of 3.4 L/m2 · min (5.0 U.S. gal/ft2 · h).  See the illustration below. 

The most essential steps in running the E547 test, once the wall assembly is attached and sealed to the ASTM E283 test wall, are listed below.  In my last blog I listed the steps for the E331 test and in this blog I have left kept those steps but in bold font for comparison.   

  1. Adjust the water spray to the specified rate
  2. Apply the air-pressure difference within 15 s and maintain this pressure, along with the specified rate of water spray for the period of time specified by the specification or the specifyer. 
  3. While maintaining the water spray, reduce the air pressure to zero for a period not less than 1 minute.
  4. Repeat the procedure in steps 2 and 3 above for the specified number of cycles.
  5. At the conclusion of the number of cycles, remove the air-pressure difference and stop the water spray. 
  6. Observe and record the points of water penetration, if any.

Note: In no case shall there be less than two test cycles, and no cycle shall be less than 5 minutes in duration. 
The test-pressure difference or differences at which water penetration is to be determined, unless otherwise specified, shall be 137 Pa (2.86 lbf/ft2). 

The test assembly is the same as that for the ASTM E331 test.  The sketch bellows shows the essential elements needed to conduct the ASTM E547 test.   

ASTM E547 test, ASTM           

NOTE: For a negative pressure system, the water-spray grid would be located outside the chamber and the air supply would be replaced by an air-exhaust system.

In Blog #25 I will begin to review methods used to evaluate in-place constructed walls for air/water leakage. These methods are often used both for determining the cause of existing building air leakage and for confirming the adequacy of newly constructed wall designs.  The list below shows what we have discussed so far and the next steps.

  • ASTM E 283 Laboratory Air Infiltration
  • ASTM E 331 Laboratory Water Penetration (Uniform)
  • ASTM E 547 Laboratory Water Penetration (Cyclic)
  • ASTM E 783 Field Air Infiltration
  • ASTM E 1105 Field Water Penetration
  • ASTM E 2128 Standard Guide for Evaluating Water Ingress

In later blogs I will discuss some of the American Architectural Manufacturers Association (AAMA) field testing such as AAMA 501.1 and 501.2 and how wind driven water testing is being conducted used as well.  To watch a three minute video for an AAMA 501.2 test, click here.

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