For an "old townhouse," I think you may want to reference the ASHRAE fundamentals table for residential constructions (Fundamentals 2001, Ch28, Table 7)... they surveyed a bunch of homes that were up to a few decades old to come up with a table that shows varying ACH rates, for "tight" to "loose" construction, varying with the OADT. The tightest value given is 0.41. Again this isn't a standard but rather based on real-world measurements.
A very good (and long) discussion thread is in the equest-users archives discussing alternate infiltration resources as well: thread title was "Basic stuff - Infiltration"
.35 ACH is the BPI standard, any tighter and mechanical ventilation is
required..
*Jeremiah D. Crossett*
For an "old townhouse," I think you may want to reference the ASHRAE fundamentals table for residential constructions (Fundamentals 2001, Ch28, Table 7)... they surveyed a bunch of homes that were up to a few decades old to come up with a table that shows varying ACH rates, for "tight" to "loose" construction, varying with the OADT. The tightest value given is 0.41. Again this isn't a standard but rather based on real-world measurements.
A very good (and long) discussion thread is in the equest-users archives discussing alternate infiltration resources as well: thread title was "Basic stuff - Infiltration"
~Nick
[cid:489575314 at 22072009-0ABB]
NICK CATON, P.E.
When doing blower door tests I have found ACH 2 or 3 to be commonplace.
*Jeremiah D. Crossett*
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