Great idea Thom and I would have looked at a single check but I have a DCVA
taking up space here and I've love to get rid of it.  So there you go..
I know the fluctuations will subside as the season ends but they'll be back
in the spring.
Average street is 80 PSI but with my hockey puck recorder I've recorded dips
to 60 PSI, so much for the 10# cushion. I purposely left about 25# on the
table for the highest density calc I had there and I'm glad I did now.
Hopefully no more rides down and plus I have to change the whole system to
glycerin as they've sold the resort to some offshore entity and the plan to
close it (just heard today) for the winter.  Glycerin has a much lower rate
of expansion than glycol/water and according to my Amtrol book, I can do a
350 gallon system with a 70 gallon expansion tank.  Yeah!

additional question...

Is a 55 gallon drum bung thread pipe thread?  I need to make a dip tube to
pump out 7 55 gallon drums of glycerin.  Anybody know?  Anyone made one?

Tom


Tom:

Why a double check, when a single check in front of the RPZ will do the same
thing with less pressure loss. Your only trying to capture the spike
pressure so your system will equalize at the higher pressure. We have been
forced to use Pressure Reducing Valves like the watts 23 HP in front of the
RPZ, then the spike hits a closed valve and goes elsewhere, much larger
pressure loss than either a single check or double check assembly, but the
big advantage is "Set it and Forget it" if it saves just one 90 min. drive
its worth it.

Thom McMahon


>I may be jumping in here a little late but I'm finding more and more
> purveyors ARE requiring RPZ's and it's really causing havoc where this has
> been enforced.  I put one in on cape cod this summer because it was close
> to
> the beach, always had to, no argument there.  I've run down there 4 times
> since because of it spitting and not stopping due to street pressure
> fluctuations (resort).  My plan is to augment the RPZ with a DCVA
> downstream
> which technically makes the spkr. system potable but it's not.  I'm so
> tired
> of the 90 min. drive each way and getting the alarm guy there that I'm
> just
> gonna retro it and hopefully be done with the 3 and 5 # checks hopefully
> holding back the surges.  I'm sure the water guy will not want this and if
> he did maybe want the RP first but I'm bolting it in right off the flange.
> I'll keep you guys posted to see if it works, I plan to go down in a
> couple
> of weeks.  He'll probably have a baby when he goes to test it next year
> but
> it's an Ames and that stupid relief cone doesn't contain the spray, it
> even
> spits during a main drain test.  What a can of worms!
>
> I'm a member of the FCCCHR and get their mailings, short money to belong
> and
> very informative btw.
>
> Tom
> GRS
> FGOL
>
> John - your postings are very informative and you sound like a great guy.
> Nothing personal was intended.  And once written it has to be enforced, we
> just don't have to buy into any misinformation about its' origin.
>
> Garth
>
>> Good try George,
>>
>> But you have to read 10.5.9 a. which only lists four permissible BFP's,
> Two
>> DC's and Two RPZ's. Take away the two DC's prohibited by  10.5.9
>> Exception
>> (3) and what are you left with ?.
>>
>> I figure by now Garth is saying that damn AHJ is behind all this,
>> actually
>> no not even a proposal, however as a code official I have no choice to
>> enforce it.
>>
>> John
>>
>> I'm surprised that contractors don't read that as saying "ya don't need a
>> BFP at all if ya gotta FDC."
>>
>> Glc
>>
>> Ps- todd, can your FD draft up 250'? holy golf ball!
>>
>>
>> The 2006 NSPC eliminated 1700 Ft FDC criteria, now any FDC equals RPZ.
>> Heres how the section now reads;
>>
>> 10.5.9 Exception (3) "Where fire protection systems include a fire
>> department connection double check valve assemblies shall not be
> permitted."
>>
>> John


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