Today I received a request to test 4 units for a small apartment building.  He says the building is 32x52 which is 1560 SF.  There is 4 apartments which are 1 bedroom and living room plus bath and small kitchen.  If I test each unit, I suspect they are approx 400 SF.  These units will have to be very tight.  He wants me to open all the doors and test from one end of the hall.  I have never done this is 10 years so not sure this is kosher.

Any thoughts.

Thanks

Jerry

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It depends on purpose of test. If it's not for program or code compliance, then testing the building as one unit makes sense. It eliminates the pesky adiabatic leakage that would occur if you tested each unit individually. If you're testing for a program or code compliance, then you need to follow the protocol called out for the test. In some cases, when individual unit must be tested, it becomes necessary to pressurize adjacent units to null adiabatic leakage, which requires multiple blower doors. But if it's 'threshold' test (i.e., pass/fail), then it may not be necessary to pressurize adjacent units if the unit being tested otherwise passes.

Thanks David.  I have participated in the adiabatic leakage testing on a 16 unit building and it seem to work good.  Had hoped to not get that involved in this small project but may not have a choice.  Keeping my fingers crossed that this builder did his job on air sealing.

New construction - commercial? If so you can test whole building as one unless inspector for some reason says test each unit 

As for adiabatic - that option somewhat goes bye bye come March (thank goodness) but ELA is brought in as an option for small multifamily units http://thehtrc.com/2018/2018-iecc-illinois-board-approved-version --- you can still do multi blower doors but then you have to be at 4 ACH for each unit

What standard are you testing to? Energy Star requires 5 ACH @ 50.   Code is 3.0 etc etc.  What is the requirement?  What is the definition of residence or home.   Code defines a dwelling (residence) includes space for living, sleeping, meal preparation, personal hygiene.   A HERS Rating includes all of these uses in the definition of a rated home.  

I recently rated a home and used the garage door for the blower door. 3 car garage with all 3 doors open, and the door to the back yard.  34 feet from the blower door to the far wall of the garage. The front door has a curved top, so it was out.  I did a multi-point.test resulted in a Flow Exponent of 0.42.   The Energy Conservatory, says Standard Results for the Exponent (slope of the line) should be between 0.55 and 0.75.  An out of limits result like this makes me repeat the test using a different door. I repeated the test the next week in a door to the deck from the main floor. No obstruction 34 feet away.  The CFM @ 50 changed and so did the Exponent.  It went to 0.62.  well within standards.  

I would not test from the front door into the hall.  You will have a blow back problem.  Is there a back door you can use.  Will the Blower Door Frame fit in a window?   A standard blower door frame will fit in a large window.  

400 sf with 8 foot flat ceiling is 3200 sf.   5 ACH will require a fan flow of 160 CFM through the fan. Energy Conservatory BD is standard with a B Ring that will get you down to 300 CFM through the fan. You will need a C ring to get down to 100.

You can pul a duct blaster fan in your blower door and get down to 20 CFM with a 3 Ring. 

FYI, he is in Illinois where code is 5 (well up until March as noted when it drops to 4) 

Heh one reason I love Retrotec - no need to buy optional rings :) Though I did see they now have a Passive House version now (Duct tester with panel which looks like it fits in windows also)

I can use my Duct Blaster on any house that I expect to be less than 1300 CFM through the fan.   I will be doing a final on a 2200 sf that had an AeroSeal and AeroBarrier applied.  Their ACH was 0.55 and TDL was 15 cfm @ 25.  I have an app that will do a multipoint and auto calculate the CFM at 50 if you don't reach 50.   It will also convert to CFM at 75.  I used this on a commercial modular built here in Wichita heading for a Code Required 0.40 CFM  per sq foot leakage at 75 for another jurisdiction.

And I don't have to carry the weight. I also have a DB A model to do the DLO.

John What are your thoughts on the AeroBarrier system?

I have done 10 houses with aerobarrier. It is impressive!  I thought at first it was a great idea but most likely a scam 2 good to be true. After the second house I was sold. It seals all the problem areas at the source point. Everything I have been telling people for yrs on air leakage it seals before your eyes. What used to take a blower door, smoke pen/machine, and FLIR camera to convince people of problems it does clear as day. Framing leaks, butt joints in osb, complicated truss areas, places you didn't know you had an issue. We are consistently able to get houses below 1 ach and a few to .4 at framing before insulation. The big surprise is how leaky closed cell spray foam houses are. If you haven't seen this technology go check it out. Or, message me for info or an installer in your area.

What standard are you testing to? Energy Star requires 5 ACH @ 50.   Code is 3.0 etc etc.  What is the requirement?  What is the definition of residence or home.   Code defines a dwelling (residence) includes space for living, sleeping, meal preparation, personal hygiene.   A HERS Rating includes all of these uses in the definition of a rated home.  

I recently rated a home and used the garage door for the blower door. 3 car garage with all 3 doors open, and the door to the back yard.  34 feet from the blower door to the far wall of the garage. The front door has a curved top, so it was out.  I did a multi-point.test resulted in a Flow Exponent of 0.42.   The Energy Conservatory, says Standard Results for the Exponent (slope of the line) should be between 0.55 and 0.75.  An out of limits result like this makes me repeat the test using a different door. I repeated the test the next week in a door to the deck from the main floor. No obstruction 34 feet away.  The CFM @ 50 changed and so did the Exponent.  It went to 0.62.  well within standards.  

I would not test from the front door into the hall.  You will have a blow back problem.  Is there a back door you can use.  Will the Blower Door Frame fit in a window?   A standard blower door frame will fit in a large window.  

400 sf with 8 foot flat ceiling is 3200 sf.   5 ACH will require a fan flow of 160 CFM through the fan. Energy Conservatory BD is standard with a B Ring that will get you down to 300 CFM through the fan. You will need a C ring to get down to 100.

You can pul a duct blaster fan in your blower door and get down to 20 CFM with a 3 Ring. 

Here are two pictures of the duct blaster fan as a blower door.  1 in a door and 1 in a window.  The woindow has a DB Fan hole in the slip.  Extra Cost about $100.   The door has a shop made insert to attach the DB an to the full size hole in the regular slip.   (BTW:  I took the picture of the wooden landing. It is maple with walnut inserts.  No nails, screws or glue.)

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Well, I think it completely depends on the purpose and requirement of the test. Testing one unit in the building makes sense but if you are testing for a small apartment then you should follow the HVAC rules of the test. Checking the individual unit is not seems good.

The most accurate way to accomplish this is to have 4 blower doors running at the same time, one for each apartment (maybe less, depending on the layout of the building). This is the only way to get individual infiltration numbers while eliminating potential leakage through the marriage walls. Similar in concept to the way we test duct leakage to outside.

Depending on the needs of the client, a single blower door for the whole building might be fine, too. Seems like it’s likely small enough for a single blower door to get a reading. 

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