High Rise Building - PRV's or Multiple Standpipes?

[NOFIRE777]

Our company is currently designing a 21 Story High Rise Building. The Local AHJ requires 125 psi minimum at each FHV and will not allow more than 175 psi at each FHV. Our initial approach was a fire pump and PRV for each floor and PRFHV's at each level. Now we are looking at possibly trying to use fire pump and have 1 low-pressure standpipe, and 2 high-pressure standpipes restricted to 175 psi. This way, we only have a few pressure reducing cla-val valves and not over 21+ PRV's and 100+ PRFHV's. Any food for thought from some of you experienced High-Rise building designers.
Thanks in advance!!

 

[TravisMack]

Based on the 125 psi requirement, I am going to guess you are in the Las Vegas area.

I completed the design on a project a couple of years back in Vega$ where we did what you described with the Cla Vals and standpipe zones.

I believe that NFPA 13, 2007 edition allows you to do this with one pump now. We just did it where we had an express standpipe up the building. We then put a Cla Val station on the 2nd floor and the 10th floor. This allowed us to eliminate the need for all of the PRV floor control and FD valves. It also saves on long term maintenance of the system. You only have to test 3 PRVs every 5 years instead of 50 or so.

I hope that helps with your question. Let me know if you need any further clarifications.

Travis

 

[LCREP]

Have you considered a variable speed fire pump and controller? They are now permitted by NFPA 20, 03 and 08 edition. The speed and pressure can be regulated by the pump speed and may save you the need for a PRV's.

****************************************
Fire Sprinklers Save Firefighters’ Lives Too

Not ALL Sprinkler Systems Are Created Equal! An Inadequate Sprinkler Design Is JUST As Bad As A Nonsprinklered Building!! When Occupancies Change So Should The Sprinkler System. See NFPA 25, 2002, Edition, Section 4.1.5, 4.1.6 & 4.1.6.1.

 

[NOFIRE777]

The Express standpipe is a great suggestion and is actually one of our options. Did you find that the cost of running the extra standpipe and cla-val station was dramatically cheaper? As far as the VFD pump controller, how do you get that to work if your pump is at Ground Level and the highest FHV is on the 21st floor (about 285 feet above the pump). I would like to look into the VFD but don't know too much about it?

 

[stookeyfpe]

Do tell Travis and InspLCrep. I haven't had an opportunity to review or test a VFD pump so I also have questions.

 

[LCREP]

I have not any projects that involved a variable speed pump. But when I was at NFPA Annual Meeting, or what ever they call it, in Boston in 07, I spoke to a few pump/controller Reps and they all spoke highly of the product. Maybe worth a phone call to the various mfg reps to see if they can help. It is just another option to look at. THEN u can share how it all went...LOL

Anyone going to NFPA in 08 in Las Vegas?

****************************************
Fire Sprinklers Save Firefighters’ Lives Too

Not ALL Sprinkler Systems Are Created Equal! An Inadequate Sprinkler Design Is JUST As Bad As A Nonsprinklered Building!! When Occupancies Change So Should The Sprinkler System. See NFPA 25, 2002, Edition, Section 4.1.5, 4.1.6 & 4.1.6.1.

 

[TravisMack]

I was working on a job with the VFD, but the contractor changed it down the road and decided to go with a standard fire pump. I like the concept of the VFD, so I am anxious to use one.

As far as costs, I think it worked out to be cheaper with the Cla Val stations. I only do the design portion of the project and don't always get to know the final numbers on a project, but customers keep coming back so I must be doing something right with keeping install costs down

With the Cla Val station, you only need to run a drain riser so that you can do the test on the Cla Val and not in every stairwell that will have a PRHV, so, we eliminated (2) 3" drain risers going up around 20 floors or so. Also, the costs savings on the PRHV and PRV floor control valve was a a couple hundred or more per floor. It has been awhile and I don't recall the exact numbers. I actually think that eliminating the extra drain risers paid for the express riser and more. Eliminating the PRHV and PRV floor control valves more than paid for the Cla Val stations. Finally, the long term savings to the owner in Inspection, Testing & Maintenance was also a big help in going that route. Finally, you also have the assurance that the valves won't get messed up and put on the wrong floor. I have seen a few jobs where fitters are scrambling to switch out valves because they are factory set PRVs and got put on the wrong floor.

Shoot me an email at tmack-at-mfpdesign-dot-com if you have any further things you need answered, or keep it on the forum as well.

Travis

 

[GrandmarkFP]

Here is a good contact for information on variable speed fire pumps and controllers.

Harvey & Associates
harveyandassociates.com
P.O. Box 818
306 Hughes Street
Fountain Inn, SC 29644
Ph. 864-862-2379
Tollfree 800-235-6703
Fax 864-862-2060



CUSTOMER: What is the difference in the large and small chili?
CASHIER: Well, …. The large is bigger than the small.

 

[GrandmarkFP]

Here is a good contact for information on variable speed fire pumps and controllers.
Bill at
Harvey & Associates
harveyandassociates.com
P.O. Box 818
306 Hughes Street
Fountain Inn, SC 29644
Ph. 864-862-2379
Tollfree 800-235-6703
Fax 864-862-2060



CUSTOMER: What is the difference in the large and small chili?
CASHIER: Well, …. The large is bigger than the small.

 

[NOFIRE777]

Thanks for all the help. I'll see what I can come up w/ and let you all know the outcome.