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.

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. 

Sorry but LMAO - one blower door for that small of a space gives you an accurate number for the building because it is no bigger than a small home. Now if the inspector for some reason wants each unit tested, well...

As for marriage wall leakage that is actually a bigger issue - forget the noise, salmon or XYZ cooking complaints but that marriage wall is also a firewall, If you have detectable measures of leakage guess what a fire is going to find and race right through? That's one of the biggest issues I have with many of these multifamily testers - they are doing a major disservice to not only the builder but the people who are going to live there & thinking it is a safe place when they do these guarded or whatever they want to call them tests

Scott Katznelson   In 2013,  I had my HERS Field Review completed on a multi-family unit.  I did and end unit, and my QAD set a blower door in the adjacent unit.  We tested both units.  The difference between guarded and unguarded was less then the +/- variance in the Multipoint Tests.  I have been involved with 3 more multi-family units since then.  I have tested at least one unit on a guarded / unguarded basis for comparison.I have consistently obtained results with this variance.  If you observe the construction and air sealing before you test,  you will eliminate the problems before you have to fix them.  We do need to get a firewall determination for all of these firewalls about what products are acceptable for air sealing.  That was the biggest problem I had with the 28 units this year.

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