Posts Tagged ‘duct testing’

Shades of Gray in Residential Construction Morality

April 27, 2015

I was called in to perform a last minute duct test for a modular home builder.  He was all in a dither to have a duct test and a blower door test done on a Friday so that he could get his Certificate of Occupancy (CO) so the homeowner could move in the following Monday.  He said that he’d just found out that he needed these tests.  The building inspector asked for them at the last minute!

I was glad to do it partially because it’s good to have builders aware of what is going on despite the fact that he might have been warned for the past year or more that the code had changed.  General awareness of these changes take time.  After all, this wasn’t the first house that he had built since the new codes went into effect, but this was obviously the first building inspector who had made him do it.  The 2012 IECC is quite demanding in contrast to the 2009 version, and it is clear that builders can’t just build the way they used to.  The IECC requires 3 ACH50 and ducts that leak no more than 4 cfm per 100 square feet.  This house leaked at over 7 ACH50 and the ducts were at just under 9 cfm per 100 square feet.

So the builder ran around with a caulking gun.  He stuffed paper towel under the basement door.  He pulled off electrical receptacle covers and installed those little foam pads.  And then he looked at me.  This is the point where the rubber meets the road as a Quality Control Inspector.  The house performed better than many houses that have been built over the years.  It wasn’t likely to explode or rot away in a year.  After all, it had been mostly assembled in a factory – indoors where it never rained.  So why didn’t the modular manufacturer get it right?  They could have sealed up the tops of all the wire chases in the attic.  There was air coming up from the marriage wall gap.  Whose responsibility was that?

We called the factory.  They were apparently shocked!  How could air be leaking at all the outlets?  Using a pressure pan I showed the builder which ones were connected to the outside and which ones weren’t.  It wasn’t all of them.  Attitude in the factory came into play.  Maybe someone had been assigned the task of sealing all those holes but ran out of . . . foam?  attitude? time?  Maybe it was Friday afternoon.

Open Panned Return1

Panned Return

Then there were the ducts.  The only return in the house was a large opening in the living room floor where the joists had been panned  down below.  There was a wind blowing up from the basement (outside the conditioned space) when the blower door was running.

We called the HVAC contractor.  “I sealed every joint with mastic!  We do that every time.  I don’t know what could have happened.”  Using the theatrical fogger, it was pretty obvious that they hadn’t sealed every joint.  The filter slot was uncovered and beyond that, it was located in such a manner that the gas pipe and some wires would always make it extremely difficult to change the filter.

By this point, the builder recognized that the house was not going to pass and he was not going to get his certificate of occupancy for Monday.   He told me that he would arrange to have the HVAC contractor back and would spend time sealing and tightening up the house.

Open Panned Return

Vision of the Living Room

A week went by before he called me back.  Now, all of this is unfortunately too common, but it was the second visit that really disturbed me.  On the phone the builder said the ducts had been retested and they were fine.  All he need from me was the blower door test.  I asked to see the duct test results.  He said that the HVAC guy was having trouble with his email, but he sent me a photograph of the test results.  I noticed that the building size was wrong.  The results were remarkably good.  I couldn’t read the signature or the name and there wasn’t a BPI or HERS number.   No, the builder said, you don’t need to retest the ducts.  Just do the blow test.

When I got to the house, the builder was running around with his caulking gun again.  Proudly he showed me how the marriage wall had been foamed in the basement.  He said he had talked to the factory but they really hadn’t done much.  I looked at the ducting.  The section of the floor joist panning was wide open at the end.  You could see the daylight of the grille in the living room.  There was absolutely no way that the testing could have had the results that it did.

While we were in the basement, the HVAC contractor showed  up and started caulking around the floor boots.  If the ducts were so tight, why was he still trying to make them tighter?  I showed him the open panned return.  “Don’t know how that could have happened!  We had a guy who was doing bad work.  I had to let him go.”

I asked him about the guy who tested the ducts.  “Oh, he’s just a guy that works for me.  Does this once in awhile.”

So the duct testing was a lie.  It was a lie by an employee who worked for the HVAC contractor.  The builder accepted it and refused to let me retest the ducts once the HVAC company had worked on them.  He wanted the CO and he wanted to be done with the job.

This situation was obvious: the end of the ducting was wide open.  Without my testing, they would never have known.  The system would have been running that way for its entire existence.  Even with my testing, the builder was willing to accept the results and walk away.  The HVAC contractor was willing to accept the results and walk away and complain about onerous rules and regulations.  The homeowner would have gotten a shoddy product and the building inspector would have received invalid information and had to accept it because he couldn’t recheck the result due to lack of time and money.

If we are going to make this system work and have any value, at the very least there ought to be simple ways to verify the credentials of the people doing the testing.  There ought to be a way for QCI inspectors to ding the contractor or the builder for making stuff up.  I want to believe that this was a learning experience for both the builder and the HVAC contractor and that they will do better next time.  But when I saw those original duct testing results from the HVAC contractor, I didn’t believe them.  Should I have compelled the builder to let me retest?  Obviously the ducting system would have failed miserably.  If it had been a health and safety situation, there would have been no question.  But it was a performance and long term durability question.  Are there shades of gray in residential construction morality?


If you are planning to challenge the BPI Quality Control Inspector’s certification, you might find the Quality Control Inspector’s Residential Handbook helpful.  Scheduled for publication on June 1, 2015.  For updates and a discount on publication, please add your name and email address by clicking on the book below.

QCI Handbook Cover copy

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What’s Your Quality Control Mission Statement?

March 9, 2015

Even with the best intentions, mistakes get made.  The meaning of mistake is defined by your Mission Statement.  A Quality Control Inspector moves the result of a project one step closer to perfection.  To do that, the inspector has to be a generalist and understand all the aspects of the project and have the experience of making his or her own mistakes and have learned from them.  The weatherization of a home has many parts from an initial analysis to determine what needs to be done, to understanding the systemic nature of construction, to appreciating the needs and resources of the homeowner, to the capabilities of the crew performing the work, to the verification that the results match the initial expectations.

A Quality Control Inspector is a residential energy efficiency professional who ensures the completion, appropriateness, and quality of energy upgrade work by conducting a methodical audit/inspection of the building, performing safety and diagnostic tests, and observing the work.
Imagine that there is a small house owned by a nice old lady who is struggling to meet her bills and tolerating exceptionally cold 090831_1474conditions in the winter and excess heat in the summer, conditions that make her life miserable.  The house fits into the local weatherization program and a BPI (Building Performance Institute) certified energy auditor has visited the house and created a work order to make improvements.  He did a blower door test to measure the leakage, measured the insulation depth in the attic, determined the existing insulation in the walls, and tested the atmospherically vented combustion, gas fired water heater, furnace and oven for safety.  And the crew comes in and begins to work.
The weatherization crew consists of a certified Crew Leader and a good crew who perform consistently good work.  You are the quality control inspector on the job and during an in-progress inspection you find that the auditor mis-identified the building envelope and the installers are not insulating a wall between the conditioned and unconditioned space, a living-room and enclosed porch. They will complete wall insulation this afternoon, according to their schedule. If you stop the job, you will miss the completion time and extend the job.  If you don’t stop the job, will you be doing your job as the quality control inspector?

Life is full of compromises.  A compromise means that you give up something to accomplish something else.  It’s the greatest good for the greatest number kind of thing not the end justifies the means.  Someone on the crew needs to understand where the thermal envelope is and point it out to the Crew Leader.  Certainly, the Crew Leader should know.  The Leader should have pointed it out to the Energy Auditor because it was wrong on the work order.  The homeowner is the one who is going to lose out because she is completely unaware of the mechanics of the problem, although she may feel uncomfortable in that room.

As the Quality Control Inspector, you should be able to turn to your mission statement to answer this question.  If your mission statement is focused on cost effectiveness, then you have to weigh the cost impact of stopping the job.  If you mission statement puts the comfort of the homeowner first, then stop the job and do it right.  But you can’t know that you have achieved success if you haven’t defined what success means to begin with.

A mission statement defines the organization’s purpose and primary objectives.  If the mission statement says that your organization’s purpose is to provide the most energy efficient, comfortable, and safe homes to your clients, then there is no question about what should be done for this home





If you are planning to challenge the BPI Quality Control Inspector’s certification, you might find the Quality Control Inspector’s Residential Handbook helpful.

QCI Handbook Cover copy

BPI Building Analyst and Envelope Professional Problems

March 11, 2014


I just taught a BPI Introduction to Building Science course last week that included both the information required for both Building Analyst and Envelope Professional.  There is an enormous amount of complex information included particularly for someone who may never have been in an attic or framed a house.  It’s all new from the second law of thermodynamics to R value to convection and boilers.  We are asking them to take in and understand and retain all of that information which has likely been shoveled at them in a week-long course.

On top of that we are working off two different Standards.  There is some information that is in the Building Analyst Standard (17 pages long) and some information in the 1200 Standard (47 pages long) (which is still a draft).  I have serious doubts that many people will actually read the new standard and refer to Paragraph to determine an action level for spillage!

And even more confusing is that the trainers have not been informed as to what needs to be taught for the tests, or if the proctors are looking for different things than the trainers think they are training for.

The 1200 Standard has removed the need for “values” – actual numbers for CAZ depressurization and draft (if it’s higher than x it’s good, lower, it’s bad).  And in fact draft doesn’t even have to be measured.  The standard only indicates if it’s bad if it spills.  Yet we are now asking for CO Airfree on some things and not on others and not all test equipment displays CO Airfree so it has to be calculated.  And the 1200 Standard says “The draft table is provided by permission of the American Gas Association” although it is referring to a table that is in draft form not to a level of pressure.  It is hard to tell what an auditor is supposed to do besides telling the homeowner that their boiler or furnace needs servicing.  Do we really need to have auditors buy an expensive combustion analyzer for that one measurement, something they probably don’t understand and can’t do anything about?

And for gas leaks we need a device that actually measures LEL which is not what the Leakator (the common combustible gas leak detector) does now so it is another piece of equipment students will have to buy and proctors will have to have available.

There are various other discrepancies that make these confusing issues a challenge to teach.  on top of those there are the various categories: Building Analyst, Energy Auditor and Home Energy Professional.  I had students go to the BPI website per my suggestion, and they down-loaded different knowledge lists.

We need an Intro to Building Science Course that one could attend to get an introductory Building Analyst Certification, Building Analyst 1.  That should refer to a “Getting Started Standard” that combined the good parts of both the old Standard and the new 1200 Standard.  The Getting Started Standard should be no more than four pages long.  Maybe it should have a bunch of pictures like the instructions that come with a new computer.


I refuse to teach to a test.  I think the students should understand what they are learning and not just memorize numbers and hose positions.  But there should be a block of maybe twenty-five items that the beginning participants could be taught that would be clear and simple.  Do we really expect them to go to Section 7.8.5, ANSI/BSR Z223.1/NFPA 54, National Fuel Gas Code, Table G-6: CO Thresholds?

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Playing a Manometer like a Stradivarius

May 12, 2013

StradivariusA Stradivarius violin is only a beautiful wooden box with strings on it until it rests in the hands of an accomplished musician who can make it sing.  But even in the hands of an accomplished musician, a violin can sound horrible if it isn’t tuned.  Building test equipment is capable of exceptional diagnostics, but only if the user knows how to use them and if the tool is calibrated.

There is so much information being transferred in a building science training class, that there really isn’t time to get beyond the basic functions of most test equipment.  And even in the ensuing years, how often does a technician take time to “play” with a digital manometer, learning the difference between stepping on the hose and having it pinched in a window frame.  What happens when the hose is attached to the Input instead of Reference tap on the manometer?  It won’t explode.  Give it a try.  What about reading the manual?

In any trade or craft, learning the basic tools is just a place to start.  Learning the shape of a letter so you can write it or learning how much paint to put on a brush before you put it on the paper or canvas won’t tell you how to write The Tale of Two Cities or paint the Mona Lisa.  Life moves so fast these days that we don’t seem to have time to linger to gain the wisdom required to use these new diagnostic tools well.  The fear is that once we’ve learned one, the manufacturer will change it so we’ll have to learn all over again.

And how do we know if the device isn’t “tuned” or calibrated?  You can hear it when a violin is out of tune.  When a digital device puts out a digital result on the screen, the inclination is to believe it.  How can it be wrong?  Maybe, with experience, we would know if it’s really wrong with an out-of-the-ballpark reading.  But what about the subtle differences if it’s only slightly out of calibration?  Does it make a difference?  The calibration schedules for most equipment are an approximation of the time the device will stay in reasonable calibration.  The fact is that it is only for sure in calibration at the moment it leaves the calibration bench, but that doesn’t mean that we should ignore the manufacturer’s advice for maintenance.

We have to be careful not to treat buildings like spacecraft.  They aren’t an exact science and never will be.  Mechanical equipment is different, however.  Our heating and cooling equipment has gotten so sophisticated that we will get less than optimum performance if they are not carefully adjusted and maintained and tuned.  And with new quality control requirements, test equipment needs to be calibrated and the calibration records maintained.

At the very least, take some time to learn your tools and read the manuals.  Like a Stradivarius, they’re not cheap.

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No Problem Here Under the Lampost!

September 21, 2012

I remember a story I heard when I was a kid about a man who comes upon another man obviously searching for something under the light from a lamppost on the street corner.  He asks the obvious question, “Lose something?”  The second man looks up and replies, “Yup.  I lost my keys.”  The first many asks, “Where did you lose them?”  The second man says, “Down the street a ways.”  Puzzled, the first man asks, “If you lost them down the street, why are you looking for them here?”  The second man looks up and replies, “The light’s better here.”


I was doing a duct test on a new house this week and couldn’t get the ducts up to pressure which generally means something’s

Where’s the Hole?

wide open – I missed covering a grille or the grille tape blew off or there’s a missing duct connection.  After checking all the obvious possibilities, sure enough, down in the crawl space, on the back side of the duct board trunk on the return, a piece of duct board had been left off.  It was just missing.


It wasn’t a bad contractor just being lazy.  It was just a mistake.  Mistakes happen.  Looking at the system, everything looked fine.  The missing piece was hidden, on the backside of the duct.  The system was working great, satisfactorily cooling the house since it was that time of year.  So a conscientious HVAC contractor wouldn’t have caught it by commissioning the system.  It would have been that way for the life of the system – a hole the size of a large pizza in the duct work, sucking air in from the crawl space. Without testing, that problem wouldn’t have been found.  And this is certainly not the first time I’ve seen this, and there are lots of people who test lots more ducts than I do.  It’s mind boggling.  It’s one of those weird LOVE/HATE things: I love finding this things, but I hate that they exist.


Contractors complain to us all the time about having to comply with new codes and regulations and those air heads in Washington who make all these new rules.  “But go ahead.  Do your testing.  Waste of time, though.  I don’t see any problems . . . here under the light.”