Maybe we could hire a bunch of homeless people to run through a building
and flush all the toilets at the same time. Sort of a man made undertow?
Just thinking...
*Ken Wagoner, SET
*Parsley Consulting***
*350 West 9th Avenue, Suite 206
*Escondido, California 92025
*****Phone 760-745-6181*
Visit the website <http://www.parsleyconsulting.com/> ***
On 09/10/2019 12:51 PM, Skyler Bilbo via Sprinklerforum wrote:
I think it is worth pointing out that the way our table reads in 13R,
and the way that the plumbing code sizes piping, uses fixture units to
convert to flow, which do not convert linearly. For example, if we had
a building with 100 fixture units, we would plug in a domestic demand
of 45 GPM and for a building with 1000 fixture units we would plug in
a domestic demand of 200 GPM (NOT 450 GPM). I believe this is done to
account for the fact that not all of the domestic fixtures are running
at once.
Back to the original question, here's what I would do (for what it is
worth). Figure the domestic demand using the table for the new
building and add it at the point of connection. Then add together the
fixture units for both buildings, find the GPM value in the table,
then deduct the GPM that I already added for the new building. I would
plug that GPM in for domestic demand for the existing building at the
point of connection.
When multiple buildings are connected to the same, small, dead end
main, there can be a very real pressure drop due to domestic water
usage (that's why we go through this excersize in the first place).
It's good to remember that this isn't all theoretical. If something
were to happen, I wouldn't want it on my conscience that I
purposefully didn't account for something that I knew could be a real
issue. If the water main is too small, then the water main is too small.
Also, I think it is worth mentioning that this may lead to a situation
we see all of the time with RPZ backflow preventers. When the pressure
fluctuates on the inlet side of the RPZ (in this case because of the
domestic demand), the relief will spray/dump and you will have a very
angry owner with water everywhere. If you are using a RPZ, put a check
valve in before the backflow to prevent this from ever happening. It
is likely that no one will know the disaster that would have been,
except you. If the backflow is a double check, this is not an issue.
Skyler Bilbo
Wente Plumbing and Fire Protection
1700 S. Raney Street
Effingham, IL 62401
217-819-6404 Direct
217-347-7315 Fax
On Tue, Sep 10, 2019, 12:37 PM Pete Schwab via Sprinklerforum
<[email protected]
<mailto:[email protected]>> wrote:
Steve
Codes cannot cover 100% of the exact situations that we will
encounter in the real world. I submitted this proposal because we
had Engineers and AHJ’s requiring domestic demand being added for
all buildings attached to a site main.
What is the likelihood of all the fixtures being used
simultaneously during a fire event? What is the impact of not
calculating that other building? 2-3 PSI? So we have a .047
Density verses a .05? Being 13R we are probably calculating a 4
sprinkler design whereas the UL 1626 test is 2 sprinklers? The
first operating sprinkler opens with the full available pressure
verses the listing? I think we are picking the fly $h!t out of the
pepper here……
Just my opinion as a member of the Residential Committee and not
that of the NFPA.
Pete
Peter Schwab
VP of Purchasing and Engineering technologies
Wayne Automatic Fire Sprinklers Inc.
222 Capitol Court
Ocoee, Fl 34761
*Mobile: (407) 468-8248*
Direct: (407) 877-5570
Fax: (407) 656-8026
www.waynefire.com <http://www.waynefire.com/>
cid:[email protected]
WAYNE_40thAnniversary (1)
*/I sleep in a sprinklered home, do you? /*
*From:*Steve Leyton <[email protected]
<mailto:[email protected]>>
*Sent:* Tuesday, September 10, 2019 11:14 AM
*To:* Pete Schwab <[email protected]
<mailto:[email protected]>>;
[email protected]
<mailto:[email protected]>
*Cc:* J H <[email protected]
<mailto:[email protected]>>
*Subject:* RE: 13R Fixture Units for Multiple Buildings
Hey Pete:
I do not recall the discussion specifically, but our intent was to
not have to put in an 8” main because of the plumbing unit values
in 13R and what the non-fire allowance would look like if you have
30 buildings on site using a common water supply. The point of
adding domestic allowance is to pad the water supply for non-fire
uses. It is counterintuitive to ignore the potential concurrent
domestic and irrigation flows that could impact the fire sprinkler
system water supply and in this case we should consider intent,
which is to assure that the portion of the site piping that serves
both buildings can accommodate all fire and non-fire flows. In
this example the calculation is being done on a satellite, not the
main building on the parcel.
SML
*From:*Pete Schwab [mailto:[email protected]]
*Sent:* Tuesday, September 10, 2019 5:10 AMth
*To:* [email protected]
<mailto:[email protected]>
*Cc:* Steve Leyton; J H
*Subject:* RE: 13R Fixture Units for Multiple Buildings
I disagree with Steve on this one
In my opinion, the intent is to only add domestic demand for *_the
building being calculated_*regardless of the underground/feed
arrangement.
If there is another “building” connected to the underground, that
domestic demand does not need to be added.
Below is the ROP from when this language was added (2013 edition).
Peter Schwab
VP of Purchasing and Engineering technologies
Wayne Automatic Fire Sprinklers Inc.
222 Capitol Court
Ocoee, Fl 34761
*Mobile: (407) 468-8248*
Direct: (407) 877-5570
Fax: (407) 656-8026
www.waynefire.com <http://www.waynefire.com/>
cid:[email protected]
WAYNE_40thAnniversary (1)
*/I sleep in a sprinklered home, do you? /*
*From:*Sprinklerforum
<[email protected]
<mailto:[email protected]>> *On
Behalf Of *Steve Leyton via Sprinklerforum
*Sent:* Monday, September 9, 2019 6:47 PM
*To:* [email protected]
<mailto:[email protected]>
*Cc:* Steve Leyton <[email protected]
<mailto:[email protected]>>; J H
<[email protected] <mailto:[email protected]>>
*Subject:* RE: 13R Fixture Units for Multiple Buildings
I think “for the building being calculated” doesn’t take into
account the potential arrangement of a single water line supplying
domestic and fire protection to multiple buildings. If I was
the AHJ, I would require the fixture load allowance of both
buildings to be added to the sprinkler demand of the subject
building for that portion of the piping that is common to both
buildings. So if you’re coming in from a meter to the main
building and call that Section A, then you have Section B going to
the Satellite building, I would calculate Satellite sprinkler
demand + Satellite domestic allowance in Section B, then at the
point where the line branches off to the main building I would add
the Main building plumbing allowance so that Section A includes
Satellite sprinkler demand plus Satellite domestic + Main Building
domestic.
I hope that makes sense.
Steve L.
*From:*Sprinklerforum
[mailto:[email protected]] *On Behalf
Of *J H via Sprinklerforum
*Sent:* Monday, September 09, 2019 3:17 PM
*To:* [email protected]
<mailto:[email protected]>
*Cc:* J H
*Subject:* 13R Fixture Units for Multiple Buildings
I've got a Bed & Breakfast (sprinklered per 13R) that is building
a second detached suite which is to likewise be sprinklered to
13R. The existing yard line supplies both the domestic and fire
demands for the existing building and the new building is planned
to also tap into this yard line.
Question: In determining the fixture units for the new building
would we also have to account for the existing building's fixture
units when calculating back to the city tap?
13R states: "9.6* Domestic Demand Domestic demand for the
building being calculated shall be included as part of the overall
system demand for systems with common domestic/fire mains where no
provisions are made to prevent thedomestic waterflow upon
sprinkler system activation."
I think the keywords are "for the building being calculated" and
we would not have to account for anything else but I'm also
thinking that if the intent is to account for water losses due to
domestic usage and we are daisy chaining off of a relatively
small, private, water line that it would be wise to account for
these losses.
Any thoughts?
JH
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