Some points:
1) Check if the available volume really is 47,040 gallons. The nominal capacity
for a tank is not necessarily the actual capacity, You’ll need to determine the
actual tank volume from the outlet point to the practical operating fill point.
The practical fill point depends on the hardware used to keep the tank filled.
That hardware can take up space. According to your numbers with four tanks
there is only 740 gallons to play with in each tank.
2) Yes venting is required and its required size is probably at least 3”
diameter. An overflow, a hatch to fit a person, an internal ladder and probably
an external visual water level indicator would be necessary. A proper outlet
system with properly designed vortex plate is necessary or you’ll be sucking
air for sure. Not knowing what the tank looks like and since the FD is using
their pump, something like a good sized dead leg where foreign objects can drop
into instead of entering their pump might be viewed as a plus to negate the
compromises this tank farm is going to have.
3) Under the best conditions with four tanks manifolded together you are
drawing about 200 gpm per tank. Assume that situation is one of the operating
conditions. Calculate the energy losses in each of the four outlet systems to
the point where the 784 gpm occurs. From the differences in each outlet system
you will have a handle on how unequal each of the tank draws. Use that
information to design the equalization piping system needed between the tanks.
The tank system is going to need two independent manifold piping systems, with
valves of course. One is for suction. The other is for tank equalization. As
any one tank draws faster than the others, the others supply into that tank.
Consider the worst case where there is only one other tank to provide the
equalization flow instead of three other tanks.
4) Under the worst condition where three tanks have been valved off for some
reason you are drawing 784 gpm from one tank. This single tank condition and
the two and three tank conditions are some of the compromises. You’ll need to
check what is going on with each in regard to hydraulics and be upfront with
the FD. The ease to which the piping system layout is understood in the field
and the access ease to its valves might come into play. There might be a need
for a third set of valves to connect the suction manifold to the equalization
manifold so that two suction can occur through two outlets at once under the
reduced tank conditions. That's assuming you were trying to use the existing 2
3” outlets and they worked for the best conditions. That’s a maze of piping and
valves that’s probably not going to happen. Good luck working with the tough
conditions.
5) One might guess frack tanks are built for short term use. Perhaps that is
why they seemed like such a deal in the first place. You may be into some
required field modifications into and inside the tank. Some tank wall thickness
beefing up might be in order at modification locations and also at existing
outlet locations. You might also be into some internal coating requirements.
Best,
Allan Seidel
> On Nov 2, 2018, at 4:37 PM, Bruce Verhei <bver...@comcast.net> wrote:
>
> Normally I assume fire department plans to operate with soft suction at
> positive connection pressure.
>
> I wouldn’t here. I know everyone hates meetings. I think one is necessary. It
> would be possible to have at least three different conceptions of project
> basics.
>
> If FD plans on using hard suction and operating at vacuum (simplified Fire
> talk for intake pressure at less than air pressure) I’d plan venting for
> maximum flow in that mode. The pump operator has a big V-8 diesel at their
> command. Limit is only pump cavitation.
>
> We rate and annual test our engines at draft.
>
> Best.
>
> Bruce Verhei
>
> On Nov 2, 2018, at 06:57, Ed Kramer <e...@bamfordfire.com
> <mailto:e...@bamfordfire.com>> wrote:
>
>> For the venting requirement, NFPA 22 section 4.15 will provide some guidance.
>>
>> Ed K
>>
>> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org
>> <mailto:sprinklerforum-boun...@lists.firesprinkler.org>] On Behalf Of John
>> Irwin
>> Sent: Friday, November 02, 2018 7:16 AM
>> To: sprinklerforum@lists.firesprinkler.org
>> <mailto:sprinklerforum@lists.firesprinkler.org>
>> Subject: RE: Always something new ... Dry hydrant?
>>
>> Matt,
>>
>> The tanks are 16.5’ tall and the outlet is 6” from the base. This is going
>> to result in positive pressure at the pump inlet. What I wonder is if I can
>> get 784 gallons from those (4) 3” outlets.
>>
>> Also, I agree that tanks need venting, but is there direction on how much
>> venting?
>>
>> What standard am I using to design this contraption? Is it 1142 for a dry
>> hydrant?
>>
>> John Irwin
>> Quick Response Fire Protection
>>
>> From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org
>> <mailto:sprinklerforum-boun...@lists.firesprinkler.org>> On Behalf Of Matt
>> Grise
>> Sent: Friday, November 2, 2018 8:07 AM
>> To: sprinklerforum@lists.firesprinkler.org
>> <mailto:sprinklerforum@lists.firesprinkler.org>
>> Subject: RE: Always something new ... Dry hydrant?
>>
>> It might be a good idea to perform a hydraulic analysis to see how much
>> water can be drawn through those 3” outlets. The pump that the FD is using
>> likely has minimum supply pressure (1/2psi or so). If you need (x) psi at
>> the pump suction flange, and you have (y) psi at the tank discharge (from
>> gravity/water level elevation), then you can flow (z) gpm through the piping
>> network before you lose too much pressure and start cavitating the pump.
>>
>> I would definitely vent the tanks!
>>
>> Matt
>>
>>
>> From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org
>> <mailto:sprinklerforum-boun...@lists.firesprinkler.org>> On Behalf Of John
>> Irwin
>> Sent: Friday, November 02, 2018 6:43 AM
>> To: sprinklerforum@lists.firesprinkler.org
>> <mailto:sprinklerforum@lists.firesprinkler.org>
>> Subject: Always something new ... Dry hydrant?
>>
>> Ok so here’s something new for me … the situation …
>>
>> Client has a client who is using a temporary, tent structure for storage.
>> And right now they are using mobile fracing water containers to supply what
>> I assume would be classified as a dry hydrant. The fire marshal wants
>> something a little more permanent. The property owner is supplying (4)
>> 12,500 gallon water tanks. They appear to each (2) 3” threaded outlets on
>> them. Whether or not these tanks are acceptable per NFPA 22 isn’t in my
>> scope. I will make some observations to them but that’s about the extent of
>> that.
>>
>> What they are asking of me: Design the manifold system to connect these
>> tanks and feed a 5” Stortz FDC for the fire department to use as a water
>> source in case of fire. It appears that the AHJ is requesting 784GPM for 60
>> minutes for a total of 47,040 gallons.
>>
>> In which standard do I turn to for the required piping configuration for
>> this and how do prove that I can supply 784 gallons in a minute through
>> these (4) 3” outlets?
>>
>> Other musings … I doubt there are vortex plates in these tanks. What’s going
>> to happen? – Is there a venting requirement to keep the fire department from
>> imploding these tanks with their truck?
>>
>> I’m looking forward to hearing your thoughts on this.
>>
>>
>> John Irwin
>> Branch Manager – West Coast
>> Quick Response Fire Protection
>> jir...@quickresponsefl.com <mailto:jir...@quickresponsefl.com>
>> CELL – 727-282-9243 <tel:727-282-9243>
>>
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