[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

GBlist: Re: leaks from central vacs

Penny said:
>...Is there no possibility of a hole or leak in [central vacuum piping]
where >allergens could escape?...

The fundamentals of an IAQ problem are a pollutant moving from a source
through a pathway by a force.  The force is usually a pressure difference.
In the case of a central vacuum, the force pulls stuff INTO the pipes.  In
the event of a leak, anything in the pipes still stays in.  (Except
downstream from the vacuum fan, which should be mounted outside anyway.)  

When the system is off, leaks could feasibly allow pollutants to reenter the
occupied space if the house was at a lower pressure relative to inside the
pipes.  The velocities are usually high enough and inside surfaces smooth
enough that not much debris will remain in the pipes though.  Common sense
during installation will prevent sharp corners, restrictions, rough spots,
traps and loose or broken joints, and ensure tightly sealed vacuum ports in
the house. 

What keeps dust mites, fleas, cockroaches, etc from crawling out of a
portable vacuum?  After you turn it off, anything in there can run or leak
back out the inlet.  Hmmm, the water-based ones may be good for something
after all...

Craig DeWitt
Clemson University

This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.