I have a question about my laboratory setup to measure heat release ra

[randymel]

I am trying to measure the Heat Release Rate from some burning mattresses as per ASTM E 1590-07. I have my fire room set up with an exhaust hood in the ceiling and fresh air intakes in the ground (to draw the exhaust up into the hood). Attached to the hood is a long exhaust pipe with a fan on the end. In the exhaust pipe are my temp, oxygen, and pressure probes. Under normal operating conditions, the correction factor (determined by regression analysis between actual and theoretical burn rate of propane) sits at about 1.45, which seems a little high to me. I know ideal is 1, but I feel uncomfortable with it above 1.2 Why do you think it may be so high? Also, when I crank up the fan, all my numbers blow up (I assume because the correction factor goes above 2.0, which is the max my system can handle). Any suggestions?