Can Fire Pumps be on a VSD/VFD?

[DownRiverGUy]

Have a 150hp fire pump that HAS to be on a generator (this is per building owner).

The issue I am running into is that with a standard starter the generator is going to be a monster!

Is there anything in NFPA that does not allow you to have any kind of "soft start" starter or something similar to run a fire pump?

 

[rcwilson]

Several manufactuers make NFPA/UL/CSA approved Fire Pump Controllers with a Soft Start feature. I just commissioned a 400 HP unit fed by a diesel generator. Works great. If the soft start fails the controller closes the bypass contactor and starts the pump across the line.

Check Eaton (Cutler-Hammer) website.

 

[petersonra]

Have a 150hp fire pump that HAS to be on a generator (this is per building owner).

The issue I am running into is that with a standard starter the generator is going to be a monster!

Is there anything in NFPA that does not allow you to have any kind of "soft start" starter or something similar to run a fire pump?

I don't know if there is a rule to that effect, but if there isn't one, maybe there should be.

If the building owner wants a generator for his fire pump, I would quote him one.

 

[petersonra]

Several manufactuers make NFPA/UL/CSA approved Fire Pump Controllers with a Soft Start feature. I just commissioned a 400 HP unit fed by a diesel generator. Works great. If the soft start fails the controller closes the bypass contactor and starts the pump across the line.

Check Eaton (Cutler-Hammer) website.

Isn't that what effectively happens with most soft starts?

 

[rcwilson]

The fire pump controller had hard wired logic that closed the bypass contactor when:
1. Soft Start output contact indicated the motor was up to speed, or
2. Soft Start's normally open "Trouble" relay contact closed indicating a Soft Start device failure, blown fuse, etc., or
3. Pump output pressure was not achieved within x seconds.

1 & 2 might be typical on most Soft Start applications.

 

[ed downey]

The only problem with using the soft start is that if it does not operate and starts across the line you will need the generator sized to accomodate that starting current.

-Ed

 

[JWCELECTRIC]

The issue I am running into is that with a standard starter the generator is going to be a monster!QUOTE]

At lease 300KW for across-line starting, but check with Cat or Kohler, they will be happy to run the generator program for you knowing you may buy one from them.

 

[iwire]

If I recall correctly fire pump controllers must be listed for the purpose.

 

[ibuildpower]

Part winding starter

Part winding starter

I wired a 12 lead Lincoln Electric fire water pump that used part winding starting to soft start. I'll bet it had some of the other sophisticated features these other units (our esteemed colleagues mentioned in other posts) had as well to insure that it would start no matter what. I agree with the sentiment, "If he wants/needs it, then quote it." It will likely be a monster and it will likely be expensive, but your owner will probably recover the expense in insurance savings. It's not a complicated fix -- all it takes is money. :smile:

 

[DownRiverGUy]

Well it won't be a fix thank goodness. Engineer here *ducks from stuff being thrown*

I just can't justify specing out a generator that is 3x the size just for one device...

Talked with a rep and they gave me the sizing program along with a tutorial.

Seems that a combination of a softer start, along with the other loads a few steps down will do the trick.

Now does anyone have experience with Wye-Delta starters compared to Part Winding starts?

Thanks

 

[iwire]

I just can't justify specing out a generator that is 3x the size just for one device

Are you sure your an engineer? <JK>

I have not found engineers to be shy about going above and beyond by a large factor.


I am sorry I do not have my code book with me but I was under the impression the generator would have to supply the fire pump with less then 15% voltage drop under locked rotor conditions?:-?

Any chance a diesel fire pump would be more cost effective if it is the only item in need of a generator?

 

[DownRiverGUy]

This job has aton of Class 1 Div 1 and Div 2 fixtures.... I can already see this being over budget.

The sizing program factors in the 15% among other things so that should work.

The building owner has a spec that requires using natural gas. If they want to go contrary to their spec then we'd be more than happy to spec a cheaper disel generator :-D

And i've only been working as an EE for 3years so I may nudge my tolerances given a few decades

 

[STHOMAS]

Every fire pump I have seen (at least 50) has had a fire pump controller. For all high-rise apps, secondary power is required. But then I reside in California...other jurisdictions may have different requirements or policies, but NFPA 20 is a national standard...

Typically, the fire sprinkler contractor will have the controller mfr rep commission the pump/controller and can usually advise of power requirements.

I would look at Chapter 6 of NFPA 20 (Standard for the Installation of Stationary Pumps for Fire) which covers power sourse(s).

 

[hillbilly1]

You could soften the blow some by backing up part or all of the building with the same generator. Load shedding can be easily be accomplished when fire pump runs. So you don't just have a big generator sitting around waiting for a fire.

 

[Cow]

Any chance a diesel fire pump would be more cost effective if it is the only item in need of a generator?

That's what I was thinking. Go with an engine driven fire pump if it'd be the only load on the generator otherwise. Less equipment to fail this way...

 

[Jraef]

Yes, you can get Reduced Voltage Solid State soft starter based fire pump controllers for the exact reason you have come across, all of the major Fire Pump Controller manufacturers have them available now. You can also get RVAT, PW, Y-D and Reactor type reduced voltage starters as well. As far as reducing line starting current, the RVAT is actually better than the RVSS, just not as flexible.

There is also at least one manufacturer I know of that now offers a UL/FM listed VFD base fire pump controller; Master Controls (excellent company by the way).

Just so you know, you must use a specially listed Fire Pump Controller in virtually every state, plus the facility's insurance company will most likely also require FM (Factory Mutual) approval. You cannot just go out and buy any old VFD or soft starter and use it on a fire pump.

 

[DownRiverGUy]

Right right. This will be a new pump/starter for the entire building.

The generator also needs to power some HVAC equipment. The A/C system and the supply and exhaust fans. The location has containers that can vent alcohol fumes... it's been an interesting project

Thanks for all the info guys. As always. top notch

 

[Bill Swain]

I don't know about that.

I don't know about that.

Not so sure that it is OK to put other loads on this Fire Pump Service, my questioning this goes back to NO Disconnecting means and the rest of the NEC.

It looks like there are other critical systems that are to be backed up (alchol fume removal) but I don't think it is OK to put them on the Fire system, i could be wrong.

Another issue is possible with a gen set, again it is no disconnecting means to be considered as a Fire System, these issues need to be clarified with your AHJ

 

[Besoeker]

Isn't that what effectively happens with most soft starts?

Yes, once the run up is completed.

 

[bcorbin]

Not so sure that it is OK to put other loads on this Fire Pump Service, my questioning this goes back to NO Disconnecting means and the rest of the NEC.

I have done this before with no problems. You just have to provide separate disconnects/ocp and transfer switches and set it up to shed the non fire pump loads.

It sure does make the $50,000 generator for the fire pump go down a little easier when the Owner gets to have his whole building backed up.