Marc:
For CO2 based DCV, note that a new proposed ventilation Standard addresses DCV in extreme detail, as well as
all other ventilation aspects.
There are new sections specifically addressing residential ventilation requirements. Also a lot of new stuff
requiring certain "commissioning" start up requirements and documentation. Certain residential buildings will
be mandated to have pressure testing requirements, including testing for negative pressure/backflow
situations, etc. IAQ contamination from building material outgassing and other sources are addressed.
This standard is refered to as ASHRAE Standard 62-1989R, "Ventilation for Acceptable Indoor Air Quality". A
second draft version was issued in August 1996 for public review and comment. It is a beefy document, chock
full of heavy duty engineering ventilation/air mixing calculatins and methodology, but it is also well
annotated in Plain English. The intent of the regulations are explained. Very helpful.
This new '89R Standard replaces the current standard now in use through out much of the US, ASHRAE Standard
62-1989, "Ventilation for Acceptable Indoor Air Quality", more or less the accepted industry standard. This
current standard is full of holes and not very precise.
There are significant changes in this new document that affect practically anyone involved with residential or
commercial systems. Like it or not, this proposed standard will become the law of the land as it is gradually
accepted by national and local codes over the next few years.
Not light reading. Simply reviewig the DCV requirements is very educational in itself.
You can download a fully formatted copy of 62-1989R, in MS Word format (.doc) at the BCBC site (interesting in
it's own right for DDC controls applications). http://www.bcbc.gov.bc.ca/
The review process for the proposed 62-1989R has expired, I believe.
My opinion of the standard: Most requirements are practical, reasonable, and long overdue. For those who
design professionally, liability exposure is always a concern... many firms have been found liable for IAQ
problems for structures designed as per code (ventilation). It is not hard to imagine what a good lawyer can
due to a defendent who designed according to applicable codes, but did not design according to "Accepted
Industry Standards". As always, codes are only minuimum standards.
Tom Anderson
Mechanical Systems Design
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