Guarded Air Leakage Testing of Large Multi-Family Buildings

Many multi-family development projects that are tied to tax credits must meet strict energy efficiency standards.   We have worked on several projects that had to score below HERS 50 and we are currently working on one that will be HERS 0.

EVERY UNIT within the building must meet the required HERS score so a major challenge has been air leakage testing.   In most units there is quite a bit of air leakage from unit-to-unit or from the unit to a conditioned hallway.   Since this air leakage is from conditioned space TO conditioned space, it doesn't have the energy penalty associated with air leakage to the outside-------------there may be other reasons to seal these leaks like odor control, sound transmission, stack effect, etc., but for these projects we are focusing on the HERS score.

Reduced air leakage, combined with ventilation per ASHRAE 62, is necessary to achieve a low HERS score.    Most apartment units we test are in the 5-12 ACH50 range and we are now trying to reduce that to 2-4 ACH50.   We suspect that most of the leakage is coming from conditioned space so we have been experimenting with different testing techniques.

Our first attempt took place in a 4-story new construction apartment  building.   We performed semi-guarded testing where we set up blower doors in 3 adjacent units, testing the middle unit while depressurizing the 2 adjacent units to -50 pascals.    This testing resulted in ONLY a 3-5% reduction in air leakage compared to normal, unguarded testing.

In our latest attempt, we performed a Whole Building Air Leakage on a 3-story 44 unit multi-family new construction project.    We first tested 7 units, unguarded, and the air leakage ranged from 9.3 to 14.2 ACH50.   We then depressurized the entire building to -50 pascals using commercial blower door fans. While the building was at -50 pascals, we used 4 technicians with individual blower doors to test each of the 44 units.   This Whole Building Guarded Test resulted in air leakage rates of 1.9 to 4.5 ACH50.    

9 commercial fans were set up to depressurize the entire building

The Whole Building Air Leakage Test allows us to demonstrate the air leakage from each apartment unit to the outside, while neutralizing air leakage from conditioned space to conditioned space.  The reduced air leakage rates we demonstrate significantly impact HERS scores.

In April of 2015 we performed a chamber test of a building, during construction, following ASTM E1186 Sections 4.1.6 (using smoke) and 4.1.7 (using liquids).

The contractor applied a spray air barrier on the face of the masonry block walls and the building owner was concerned that the material wasn't applied thickly enough.    We built our testing chamber on the exterior of the wall to examine a small portion of the completed wall:

Small pin holes were visible throughout the tested assembly:

Utilizing theatrical smoke, there didn't appear to be much air movement around these small pin holes. However, when a liquid solution was applied to the tested surface, air movement became very evident.

The chamber was very helpful in demonstrating that the air barrier had not been applied thickly enough to totally eliminate all potential leakage sites.    Please visit www.tsienergysolutions.com for more information on our testing services.

Air Barrier Testing Video

We recently created a video that shows our entire process of testing a building for air leakage per ASTM E779 and ASTM E1827 and thermography using ASTM C1060.

Visit this link to view our new video on YouTube:  http://youtu.be/eh8MZeNiyA8

or watch it from our web site:

http://www.tsienergysolutions.com/Air_Leak_Test_ASTM_E1827.html