With the increasing demand for green building practices, high performance building envelopes, and required building testing by the Washington State Energy Code, it’s no wonder this type of performance testing has become popular over the last 3-5 years. There’s no slowing down in sight either, at least in the Pacific Northwest.
Many clients who have never been through testing before always ask the same question: What is the purpose of a whole building air barrier test? Commonly, new buildings are under pressure to become more and more energy efficient. The desire to reduce energy usage and cost is continually growing. When a significant amount of money is spent on heating and/or cooling a building, the last thing you would want is to have that expensive conditioned air leaking out of openings throughout your building envelope. Testing the building for air leaks determines how well it will perform as related to energy efficiency and leakage of conditioned air. At the end of the day, it’s a quality control program to make sure everyone throughout the construction process has built a quality, efficient building. In some cases, the HVAC system is sized based on the air leakage performance of the building.
There are many options when it comes to testing agencies: who is the right company / person for the job? This article is not intended to be a sales lecture for QED, but rather to educate the reader on the hidden secrets of our industry.
Importance of Equipment and Experience
First and foremost, your testing agency should be using calibrated equipment. Omission of a calibrated system can provide a false pass, or a false failure and neither of those results are warranted. Any test performed should be as accurate as possible, beginning with the appropriate calibration and documentation of the equipment used in the test. I can’t tell you how many times a client has called looking for a second opinion on testing as their first test went haywire with dramatic failure results, only to learn the technician was using non-calibrated equipment and had inappropriate training.
This segways into the next topic of technician training and/or certification. Any Joe Schmo can buy a few fans on eBay and hit the big green button. Remember, this test is required in Washington to obtain your certificate of occupancy, and often times is used for energy tax credits or LEED points. At the end of the day the accuracy of the test is everything, which the testing technician certainly plays a big part. Common tech training includes, but is not limited to certification through the equipment manufacturer, licensed mechanical engineer, or another entity like ABAA or Passive House. The real intent with training is a formal process through a reputable organization.
There are a variety of factors for whole building air barrier testing regarding building preparation and test equipment setup. The competency of the testing technician plays a critical role in this process.
Building Preparation
There are multiple systems in a building which are excluded from the test. These systems are more or less: HVAC, plumbing, and electrical. The biggest emphasis here is HVAC systems. For instance, in a residential building such as a mid-rise apartment building, there is a very large amount of individual HVAC features. Some of these things may include bathroom exhaust fans, dryer vents, range hood vents, AC ports, not to mention supply and exhaust for common areas. All of these ducts and vents need to be covered for the test to prevent airflow in or out of the building. For commercial buildings such as offices, hotels, schools, etc. the HVAC units tend to be larger and roof-mounted. The same isolation requirements are necessary, but a different type of technique is used to get the job done. In QED’s case, we always provide the isolation service for the client. This eliminates the contractor and their laborers incorrectly preparing the building and potentially being liable for a false failure. We at QED have staff specifically trained for building preparation and we use all the right materials to make it happen. A benefit of the testing agency prepping the building is a huge labor and supplies savings for the contractor.
Electrical and plumbing systems are much easier to exclude. Generally plumbing systems just require water in the P-traps and you’re all set. Electrical systems are commonly smoke seals around conduits or open conduits connecting the building interior to the exterior or parking garage. Just install a little bit of fire foam or caulk and you’re ready to go. Make sure to check with the electrician or plumber for the appropriate sealing method.
In addition to excluding HVAC, Plumbing, and Electrical systems, there are additional building preparations needed. Every interior door must be propped open. Every exterior door and window must be closed and locked. Any temporary condition (commonly omitted weatherstripping, door thresholds, and other incomplete conditions) must be simulated for the test. For the best results, incomplete systems should be as minimal as possible.
So, obviously building preparation is a huge part of any test. In our experience, the best team to perform the building preparation is the testing agency. Why? Because we know exactly what to do and we’re very efficient. You can imagine the chaos (and liability) if an inexperienced team prepares the building, and the test results in a failure because of improper building preparations. We’ve seen it too many times and it creates a huge political mess. For these reasons, QED always includes building preparations with every air barrier testing proposal.
Test Equipment and Industry Standards
The installation of testing equipment is a fragile balance of strategy and organization. On any given test we have hundreds of feet (sometimes thousands) of power cords, pressure measurement tubes, computer cords, and so many other critical equipment placements. With many tasks to coordinate, just one pressure tube in the wrong place can skew the test. So once again, the competency and training of the testing technician is critical for an accurate test. As an example, see the photo at the top of this page. This is a test of a 200,000 square foot K-8 school using 9 fans. Approximately 2,500 feet of cord, hose, and wire were used in this test.
Like all tests, air barrier testing is performed in accordance with a certain industry standard. In most cases, it’s ASTM E 779 or ASTM E 1827. There are other common test procedures, but ASTM E 779 is the most common. Within these standards are up to 7 pages of very complex equations for calculating the test results. Most testing agencies have a tendency to use software to perform all of these calculations, as well as operate the test equipment. Not only is it accurate every single time, but it eliminates the human error factor to a certain extent. The tech is still required to input all the appropriate information into the software, such as weather conditions, building envelope and floor areas, elevation above sea level, etc. The software isn’t required to perform a test by any means, however it’s generally considered the most efficient and accurate method for many professional testing technicians.
Over the years, the testing industry has become more efficient and therefore more affordable. Some mindsets are that whole building air barrier testing is a very expensive process. You might be surprised how affordable it is, especially for simple structures, such as single family homes, townhomes, etc. Commercial buildings and mid-rises / high-rises are obviously more complex tests and the fee structure is relative, but the days of $50,000 tests are long gone. These complicated tests historically have taken a week or so to prepare and perform. Now we’re down to a single day in most cases (occasionally 2 days) thanks to efficiency and training of testing technicians.
It is my recommendation during this booming time in construction and green building that we all work together to build efficient, air-tight buildings. Lets all review specifications and details as a team. Lets generate the appropriate plan for testing, and quality check the performance of air leakage in your new building.
We’re happy to assist with your project and help you through all of the requirements for testing. QED is an expert source in our industry, so feel free to utilize us as an asset on your current or next project. We appreciate you visiting our website to educate yourself and we encourage you to take a look around at the other services we provide, such as window testing, roof testing, laboratory services, and more.
Author:
Mike Poirier
Vice President, QED Lab Inc.
Certified Level III Testing Technician