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fire sprinkler systems



>From my brother-in-law in Atlanta who sells fire protection equipement.
Essentially the same story:

The only alternative to a glycol-based wet sprinkler system is a dry
pipe Pre-action Sprinkler System. Gaseous Systems are not effective at
temperatures below 40F, and are generally designed for 60F - 70F
applications in high-value areas, ie, Data Centers, Telephone Switch
Rooms, etc.



----- Forwarded by Bill Hanson/DC/USEPA/US on 10/25/02 04:15 PM -----
                                                                                                         
                      Gaithermj@aol.com                                                                  
                      Sent by:                  To:      p2tech@great-lakes.net, herbdw@michigan.gov     
                      owner-p2tech@grea         cc:                                                      
                      t-lakes.net               Subject: fire sprinkler systems                          
                                                                                                         
                                                                                                         
                      10/25/02 12:40 PM                                                                  
                      Please respond to                                                                  
                      Gaithermj                                                                          
                                                                                                         
                                                                                                         




Herb, here are some codes and a potential option for you, from my
husband,
who's in the fire protection biz. i believe you meant to say "other than
dry
pipe: in your request, but my husband commented on those types of
systems).

FYI:  NFPA 13, Standard for the Installation of
Sprinkler Systems, will only allow pure glycerine (C.P. or U.S.P. 96.5
percent grade) or propylene glycol for sprinkler systems connected to
potable water systems.

A mixture of 50% glycerine and 50% water protects
against freezing for temperatures down to -20.9F, while 50% water/50%
propylene glycol protects down to -26F.  Although still undesirable in
the
event of drainage to the stream, perhaps increasing the water
concentration is an option?  antifreeze systems are limited to sprinkler

systems with a volume capacity of 40 gallons or less; so, the actual
discharge of the non-toxic antifreeze agent would be 20 gallons or less
for a
50/50 solution.

Even so, if toxicity is a concern, there are additional alternatives.

In general, I stear clear of utilizing antifreeze systems because the
maintenance is costly over time and you cannot always guarantee that the
mixture in the far ends of the pipes is suitable to prevent freezing.
Here
are some alternatives:

Dry Pendant Heads: Remove the existing antifreeze system and install dry
pendant heads.  If the loading dock is 7 feet wide or less, the area
can be
protected with dry pendant heads extending through the heated side of
the
outside wall at a 45 angle.  These heads are directly connected to wet
pipe
sprinklers in the heated building.  They are designed to extend into
freezing spaces (i.e., a freezer).  The angled orientation will allow
them
to throw out to the end of the canopy.  See NFPA 13, A.8.14.7

Dry Pipe Protection: Install a dry pipe valve in place of the antifreeze
fill
system.  Annual maintenance is about the same, but the environmental
impacts
are less and the guarantee against freezing is much better.  The piping
may
need to be slightly revised to ensure proper drainage (dry pipe
systems cannot have trapped piping sections - they must slope  to 
inch
per 10 ft. for proper drainage).

Heat Trace & Insulate: If the antifreeze system is not too large, it can
be
heat traced and insulated.  The temperature must be maintained above
40F
but less than 120F.  This is only acceptable for small unheated areas
such
as a small canopy and is the least desirable of the above alternatives.

Michelle Gaither
Tech Lead, PPRC
www.pprc.org

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