ventilation holdup question

["Minnema, Douglas" <Douglas.Minnema@ns.doe.gov>]

RADSAFErs,

I have a quick technical question that I'm sure somebody can answer off the
top of their head.

Assume that a puff of gas is released into a room that has a ventilation
system operating with X room-changes per hour.  How do I calculate the
'average' time (or whatever is the appropriate metric) for that puff to be
released from the room?  I know that this release would actually look like a
distribution curve, but all I need is an 'average holdup time' in order to
estimate the amount of decay in a short halflife isotope before it is
released.

Thanks,

Doug Minnema, PhD, CHP
Defense Programs
US DOE
<Douglas.Minnema@ns.doe.gov>


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