Basic CAZ instructions may not provide the correct number.

When you measure the worst case depressurization of a CAZ are you measuring the pressure in the appliance room or the room above it?  When your appliance room is in the basement and you run your reference tube upstairs and out the front door, your reading is actually for the room above at the same elevation as the point where your reference tube exits the envelope.  On a cold day, that can change your reading by a couple of Pascals.  And that can be the difference between passing and failing for some appliances.

We all know that the stack effect pressures vary from ceiling to the basement floor and they change with every foot of elevation.  So, how do we measure the pressure in a basement surrounded by dirt and no way to place our reference tube out through a concrete wall?  We calculate the change per foot for the given temperature difference and adjust our reading to the elevation we need.

Anyone doing this?  Anyone  interested?

Bud

Tags: CAZ, reference, tube

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