Heh, How old is that bet?
Benjamin Young On Thu, Jun 17, 2010 at 4:07 PM, Reed Roisum <[email protected]> wrote: > > So there is a use for differential equations. WOW. Guess I need to pay > up. > > > Reed A. Roisum, CET > Ulteig Engineer, Inc. > Engineering Technician > > > Direct: (701)280-8580 > Cell: (701)212-8810 > > > > > > -----Original Message----- > From: [email protected] [mailto: > [email protected]] On Behalf Of Law, Kevin W > Sent: Thursday, June 17, 2010 2:33 PM > To: [email protected] > Subject: RE: Gravity Tanks > > Of course depending how high the tank is mounted in relation to the level > of discharge the available head will vary which will affect the rate of > discharge.......seems to me from my college days(now becoming only a distant > memory) that this would be an excellent example for the use of differential > equations to solve for the actual performance of the system over time. > ............Sounds like a good thing to have an intern figure up for ya' > > > > > Kevin Law, PE > Bechtel National, Inc. > Waste Treatment Project > Fire Protection Engineering > Work (509) 371-3280 > Cell (509) 531-5715 > > > -----Original Message----- > From: [email protected] [mailto: > [email protected]] On Behalf Of Ron Greenman > Sent: Thursday, June 17, 2010 10:57 AM > To: [email protected] > Subject: Re: Gravity Tanks > > Art, > > The reason to assume it is empty is because it might be at the end of your > required duration without replenishment. Of course if when it's full the > capacity is twice the duration then you can figure it at half empty. If > there is replenishment at you know the rate you can add that to the mix and > perhaps at the end of duration it would only be 2/5ths empty. Each tank has > to be calculated to friction loss and elevation as you say but if you don't > have all the pertinent values, most of which were not stated in the original > post (duration, capacity, replenishment rate) then you have to assume you > start with an empty tank for calculation purposes. > > On Thu, Jun 17, 2010 at 8:04 AM, Art Tiroly <[email protected]> > wrote: > > Is this tank dedicated for fire protection? Why would you assume it is > > empty? Then the water is only available for 1 minute while you empty > > the riser pipe. Calculate friction loss through riser pipe down and > > through sprinkler riser with an assumed flow entering the tank discharge > pipe. > > Eleveation and friction loss is what you are calculating. > > > > What about doing a flow test from the base of the riser? > > > > Arthur Tiroly > > ATCO Fire Protection Design > > Tiroly and Associates > > 216-621-8899 > > 216-570-7030 Cell > > WWW.ATCOfirepro.com > > > > > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of Todd > > Williams > > Sent: Wednesday, June 16, 2010 7:17 AM > > To: [email protected] > > Subject: Re: Gravity Tanks > > > > I appreciate everybody's input. What about this? > > Calculate the flow rate discharging at the bottom of the tank at the > > pressure due to the elevation of the water in the tank. I found a > > website that apparently will do that, > > http://www.efunda.com/formulae/fluids/draining_tank.cfm#calc. > > The static and residual pressures will be close to the same but will > > decrease over time with the drop in water elevation. You could even > > make the assumption on a residual pressure based on elevation after 1 > > minute of discharge and it would be conservative. So now you have a > > static, residual and flow at the tank discharge. Then you could run it > > through the piping down through the building (in this case) as you would > any water supply. > > > > > > > > > > > > At 10:18 PM 6/15/2010, you wrote: > >>I think Ralphy has it right. The empty tank level is the worst case > >>pressure condition and in the big picture the falling tank head is > >>nothing compared to 28 floors of head unless the tank height is a few > >>sizes bigger than King Kong. A surprising calculation to make might be > >>the tank stored gallons divided by the system gpm. > >> > >>On Jun 15, 2010, at 2:40 PM, Ralphy Henderson wrote: > >> > >> > Couldn't you also do this: > >> > > >> > For assumption sake let's say 1st floor is light hazard and we're > >> > anticipating we're going to need 400 gpm. Plot out the static > >> > pressure of the tank (at the empty level) over zero gpm then > >> > calculate our friction losses through the main from the water tank > >> > down to the first floor based upon our anticipated 400 gpm and > >> > subtract that from our static to get our residual pressure. Plot > >> > out the residual pressure over 400 gpm and we now have a standard > >> > water supply curve that can be used to determine other pressures at > >> > available flows. > >> > > >> > --- On Tue, 6/15/10, Brad <[email protected]> wrote: > >> > > >> > From: Brad <[email protected]> > >> > Subject: RE: Gravity Tanks > >> > To: "'Matt Grise'" <[email protected]>, > >> > [email protected] > >> > Date: Tuesday, June 15, 2010, 5:44 PM > >> > > >> > For turbulent (sprinkler) flows, friction loss is proportional to > >> > the square of the velocity > >> > > >> > -----Original Message----- > >> > From: Matt Grise [mailto:[email protected]] > >> > Sent: Tuesday, June 15, 2010 12:41 PM > >> > To: '[email protected]'; '[email protected]' > >> > Subject: RE: Gravity Tanks > >> > > >> > Don't forget friction in the pipes! > >> > > >> > Matt Grisé PE*, LEED AP > >> > Sales Engineer > >> > Alliance Fire Protection > >> > *Licensed in KS & MO > >> > > >> > 913.888.0647 ph > >> > 913.888.0618 f > >> > 913.927.0222 cell > >> > www. AFPsprink.com > >> > > >> > > >> > -----Original Message----- > >> > From: [email protected] > >> > [mailto:[email protected]] On Behalf Of Brad > >> > Sent: Tuesday, June 15, 2010 12:39 PM > >> > To: [email protected]; [email protected] > >> > Subject: RE: Gravity Tanks > >> > > >> > i.e., if the water level is 280 feet 'above your head', then h=280 > >> > ft, v=134 ft/sec (same as the Law of Falling Bodies- if you were > >> > dropped from 280 ft, you would be going 134 ft/sec when you hit the > >> > ground). > >> > ft/sec*ft^2=ft^3/sec. If the flow is coming out of 4" pipe, ft^2=. > >> > 09---- > >> > *134= 12 * 7.48= 90---- * 60= 5400 GPM. As the level 'above your head' > >> > drops, so does the velocity, so either use calculus, or call h the > >> > bottom of the tank, like I would have to do. It still seems like > >> > magic to me that by just using feet and seconds, given the rated > >> > psi and rpm ONLY, of a fire pump, I can calculate the diameter of > >> > the impeller (v=2*pi*r*f). It seems like magic bcoz for 15 years I > >> > tried to learn sprinkler calcs after the PEs had simplified it > >> > enough for me by factoring gravity out of the formulas. > >> > > >> > -----Original Message----- > >> > From: Brad [mailto:[email protected]] > >> > Sent: Tuesday, June 15, 2010 8:30 AM > >> > To: [email protected] > >> > Subject: RE: Gravity Tanks > >> > > >> > mgh=.5mv^2 > >> > m is the same on both sides so > >> > v= sq root 2gh > >> > h= v^2/2g > >> > first thing is forget about gallons, minutes, and psi- use feet and > >> > seconds: > >> > ft, ft^2, ft^3, sec, sec^2. ft/sec=(ft^3/sec)/ft^2) > >> > g=32.2 ft/sec^2 (if this project is on the earth). 7.48 gal/ft^3. > >> > water > >> > weighs 62.4 lbs/ft^3. > >> > > >> > -----Original Message----- > >> > From: Todd Williams [mailto:[email protected]] > >> > Sent: Tuesday, June 15, 2010 5:11 AM > >> > To: [email protected] > >> > Subject: Gravity Tanks > >> > > >> > Was there a thread on calculating flow from a gravity tanks a while > >> > back? I couldn't find it. I have to do a calculation on the first > >> > floor of a building fed from a gravity tank on the 28th floor > >> > > >> > Todd G. Williams, PE > >> > Fire Protection Design/Consulting > >> > Stonington, CT > >> > 860.535.2080 > >> > www.fpdc.com > >> > > >> > _______________________________________________ > >> > Sprinklerforum mailing list > >> > [email protected] > >> > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >> > > >> > For Technical Assistance, send an email to: > >> > [email protected] > >> > > >> > To Unsubscribe, send an email > >> > to:[email protected]<to%[email protected]> > >> > (Put the word unsubscribe in the subject field) > >> > > >> > _______________________________________________ > >> > Sprinklerforum mailing list > >> > [email protected] > >> > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >> > > >> > For Technical Assistance, send an email to: > >> > [email protected] > >> > > >> > To Unsubscribe, send an email > >> > to:[email protected]<to%[email protected]> > >> > (Put the word unsubscribe in the subject field) > >> > > >> > _______________________________________________ > >> > Sprinklerforum mailing list > >> > [email protected] > >> > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >> > > >> > For Technical Assistance, send an email to: > >> > [email protected] > >> > > >> > To Unsubscribe, send an email > >> > to:[email protected]<to%[email protected]> > >> > (Put the word unsubscribe in the subject field) > >> > > >> > _______________________________________________ > >> > Sprinklerforum mailing list > >> > [email protected] > >> > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >> > > >> > For Technical Assistance, send an email to: > >> > [email protected] > >> > > >> > To Unsubscribe, send an email > >> > to:[email protected]<to%[email protected]> > >> > (Put the word unsubscribe in the subject field) > >> > > >> > > >> > > >> > > >> > _______________________________________________ > >> > Sprinklerforum mailing list > >> > [email protected] > >> > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >> > > >> > For Technical Assistance, send an email to: > >> > [email protected] > >> > > >> > To Unsubscribe, send an email > >> > to:[email protected]<to%[email protected]> > >> > (Put the word unsubscribe in the subject field) > >> > >>_______________________________________________ > >>Sprinklerforum mailing list > >>[email protected] > >>http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >> > >>For Technical Assistance, send an email to: [email protected] > >> > >>To Unsubscribe, send an email > >>to:[email protected]<to%[email protected]> > >>(Put the word unsubscribe in the subject field) > > > > Todd G. Williams, PE > > Fire Protection Design/Consulting > > Stonington, CT > > 860.535.2080 > > www.fpdc.com > > > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > > > For Technical Assistance, send an email to: [email protected] > > > > To Unsubscribe, send an email > > to:[email protected]<to%[email protected]> > > (Put the word unsubscribe in the subject field) > > > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > > > For Technical Assistance, send an email to: [email protected] > > > > To Unsubscribe, send an email > > to:[email protected]<to%[email protected]> > > (Put the word unsubscribe in the subject field) > > > > > > -- > Ron Greenman > Instructor > Fire Protection Engineering > Bates Technical College > Tacoma, WA > > Member: > AFT WA 4184/AFL-CIO, SFPE, ASCET, NFPA, AFSA, NFSA AFAA, NIBS, WSAFM, WFC > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected]<to%[email protected]> > (Put the word unsubscribe in the subject field) > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected]<to%[email protected]> > (Put the word unsubscribe in the subject field) > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected]<to%[email protected]> > (Put the word unsubscribe in the subject field) > _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
