We start at the highest pressure and work downward for two reasons. 

1. It helps the fans reach the target pressures faster. The speed control algorithm works faster going from a higher pressure to a lower pressure.
2. It helps you properly select your Range Ring for the test. By starting with the largest possible range (highest flow) to test at your highest pressure you ensure the minimum possible range changes while testing. Ideally, you don't want to change ranges in mid test because it wastes time. 

You need to consider that there is a fundamental issue of uncertainty with using 4 Pa as a reference pressure. Just imagine, if there is even a 1 Pa fluctuation, due to so many possible sources that can cause pressure fluctuations as you know, the pressure measurement already has an uncertainty of +/- 25% error. Consider that for almost all airtightness testing standards across the world, the reference pressure for Flow results are either 50 Pa or 75 Pa.

The main disadvantage to positive duct test pressure is that it blows off register seals or makes them leak. An LBL study showed a wide dispersion of results when the same duct test was repeated many times.  Depressurizing will allow the use of lower sticking masking materials that are less likely to pull off the paint. In some cases plastic food wrap will work.

The main advantage to positive duct test pressure is that the flex duct doesn't contract as much. In cases where the flex runs to the ceiling this contraction effect might cause problems.

Testing using depressurization will usually result in less leakage because gaps and seams will be pulled closed”

I have a Energy or Enclosure Integrity Test to perform.  How many fans do I need to properly run the test?  Do I have enough fans to run the test?

We have created two tools to help you figure out how many fans you will need for your test. 

Download either the Blower Door or Enclosure Integrity version of the Number of Fans Calculator. 

Next, open the file in excel and "Enable Editing" when a security warning appears.

Fill in all the fields highlighted in blue.  The number of fan results are highlighted in green.

Here is what the Blower Door Number of Fans Calculator looks like:

How and when should I compensate for leakage around the door panel?

Yes you can print your results via the rCloud portal. Just login to the rCloud web portal, find your report and you can save your report as a PDF to be printed.

500 Flow Chart

6000 flowchart

Currently none of the standards require independent or 3rd party testing.  Much of this responsibility is given to the AHJ who is supposed to ensure all codes are followed. The reality is few AHJ completely understand the standards and are easily persuaded by the installer that everything has been done correctly. Increasingly the role of ensuring the building is up to spec has been taken on by commissioning agents. Their job is to ensure that the entire building is up to spec and that includes the suppression system. The commissioning agent is hired by the owner to ensure the owner is getting what they paid for, which includes compliance with all building and NFPA codes.

We often get questions from AHJ or commissioning agents who are concerned about how the enclosure test was performed, and there is good reason for this. Half the enclosure integrity tests done in Europe and 60% of those performed in the US do NOT include a peak pressure evaluation. Peak pressure evaluat