Ventilation Requirements for Weatherized Homes
Is the ASHRAE 62.2 ventilation standard too complex and expensive?
I went to school with Cajuns in south Louisiana, and fights were a big deal. They happened frequently, and when they did, a small crowd would gather. The noise would grow quickly and soon everyone in the schoolyard would run over to where the fight was happening. One day in sixth grade, we exploited this tendency and staged a fight between two shoes at recess. Sure enough — our tight circle of boys banging two shoes on the ground and making a lot of noise brought the whole school to us.
Today, I'm making noise for a fight that broke out over the topic of residential ventilation. This is a real fight among two heavyweights in the home performance industry: John Krigger of Saturn Resource Management and Paul Raymer of Heyoka Solutions.
Don't worry; it's not a Jon Stewart/Tucker Carlson kind of fight or something you might see on the Jerry Springer show. These guys respect each other and even teach classes together. It’s a very real debate, though, about fixing homes, making them tighter, and adding mechanical ventilation when necessary.
In this corner...
Krigger opened the battle recently with a roundhouse punch aimed at ASHRAEAmerican Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). International organization dedicated to the advancement of heating, ventilation, air conditioning, and refrigeration through research, standards writing, publishing, and continuing education. Membership is open to anyone in the HVAC&R field; the organization has about 50,000 members. and the latest versions of their residential ventilation standard. "ASHRAE 62.2-2010 is a confusing jumble of requirements and choices that has wasted vast amounts of time and money in training personnel and coping with confusion," he wrote. Krigger doesn't like it that so much time and money is being spent in the home performance and weatherization industry to train people on this standard. Now the requirements ares about to change again with the 2013 update, "which will be different and lead to another cycle of confusion and wasted resources," according to Krigger. He believes there's no reason to move away from the 62-89 version because the older version is much simpler.
In addition, he claims that the assumptions on which they've based the changes in the standard are questionable; he lists four problems at the end of his article. I'll let you go and read them and decide for yourself, but I will mention one here. He wrote that, "There are millions of respiratory problems relating to a lack of ventilation." When I posted a link to the article on LinkedIn, Bobby Rhett, an industrial hygienist in the Washington, D.C. area, replied, "We may not always have the source of asthma pinned, but there is evidence that improving ventilation improves asthma outcomes."
In the other corner...
Raymer responded with a jab, aiming to connect quickly and thus take some of the impact out of Krigger's blow. His article, titled, Don’t Blame the ASHRAE 62.2-2010 Standard, disputed Krigger's claim that ASHRAE moved away from simplicity when they revised the standard from their first version, 62-89. That early version, he wrote, was 26 pages long, while the 2010 standard is only 14. "The ASHRAE 62-89 Standard is no longer supported by ASHRAE partly because of its complexity," Raymer explained.
He then went into some of the details of the two versions of the standard, offering a nice contrast between how they really work. One important point that many in the home performance and weatherization field probably don't know is that, "there is nothing in the 62-89 Standard about calculating a Building Airflow Standard, Building Tightness Limit, Minimum Ventilation Level, etc." Those terms come from the programs that reference the standard.
How many rounds will it go?
In case you don't know who they are, both Krigger and Raymer are heavyweights in this field. Krigger is the author of the book Residential Energy, which is used, I imagine, in nearly every building analyst and home energy rater class in the U.S.
Raymer is the author of the Residential Ventilation Handbook, which covers the whole topic extensively. He's also on the ASHRAE committee that decides what goes into the 62.2 standard and issues the new version every three years.
How we ventilate homes is a big deal and far from settled. ASHRAE 62.2 is leading the way, but as you can tell from this fight, there is pushback from some of the people who have to apply the standard in the field. The Building Performance Institute (BPI) was supposed to drop 62-89 and adopt 62.2-2010 this month but released a statement on 28 December announcing they'd postponed that change.
Both of these guys make good points, but I have to side with Paul on this issue overall. I think BPI should have dropped 62-89 long ago, and to keep postponing it only makes it worse, as more people get trained on an obsolete standard that was created in the 1980s. John definitely makes some good points, and I think we can do a better job of considering the training aspect of applying standards. Part of that falls on the organizations that adopt the standard, too.
Paul's basically right, though, that we need to go with the newer version. Yes, it needs work, but the three-year cycle is getting us there.
This is an important battle in the Building Science Fight Club. It's not just a bunch of sixth graders banging shoes on the ground to get attention. We need to ventilate homes to improve indoor air quality, and we need to be able to do it cost-effectively. Debate and discussion are healthy, and we need to keep it going. I'd love to see John and Paul do an evening session at the RESNET conference this year and continue this debate.
Blower doors and mechanical ventilation
One problem here is that weatherization and home performance crews are trying to use blower doors to determine if they need to add mechanical ventilation. Joe Lstiburek wrote about this issue in his article Just Right and Airtight. After opening with praise for using a blower door to help make homes more airtight and to measure leakage, he then wrote:
But then they think that a blower door actually is a precise measuring tool for how air will leak across the building during service. Wrong. Even more serious an issue is to then take the leap that using a wrong assumption about the results of an approximate measurement can be used to decide that mechanical ventilation is not needed. Bad, very bad, and potentially deadly.
I wrote about the problems with ACHnat here recently, and that’s what Joe’s referring to above. What he says they do at Building Science Corporation is, “To me, the ventilate right part is easy: put in a ventilation system and pick a rate." In footnote 4 of that article, he describes that their method is to install a system that’s capable of providing 1.5 times the ventilation rate recommended by the latest version of ASHRAE 62.2.
This is an important debate because we want homes to be have less air leakage. We also want them to have good indoor air quality, and that means mechanical ventilation. Krigger makes some good points about all the resources going into training for ASHRAE 62.2, but the time has come to drop the Building Airflow Standard and stop pretending that blower doors can tell us how much mechanical ventilation a home needs.
- The Cosmopolitan of Las Vegas, from flickr.com, Creative Commons license
- Energy Vanguard
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