Jockey Pump too Cold?

[jaymiess]

This is not my specialty but I want to see if my suspicions might be correct. Hopefully someone here can perhaps answer my question.

Would it be possible to have activation of a sprinkler head in a wet system due to water freezing in the jockey pump? I have a case like this where the jockey pump was in a very cold room at the roof level but the sprinkler head activation occurred in a warm area of the building. Happened on an extremely cold day, and possible one of the heaters in the jockey pump room was not on (the other blowing cold air... it was definitely very cold in the room). Is it possible ice formed in the pump and clogged the piping several floors down, thereby raising the pressure in the lines and causing a head activation? Otherwise this one has me stumped.

Thanks for any thoughts.

Jay

 

[cdafd]

Should not
If the head itself and piping to it were in a heated area jockey pump should not have mattered

So what kind of room was it in?? What was going on in the room

Glass bulb?

Reachable from someone standing on the floor??


If multi story building what floor of what floor was the head on?

 

[jaymiess]

Yes it was a glass bulb. Actually there were three different sprinkler head activations in this building on this particular night (all glass bulbs I believe), one of the coldest of the year. Fire department came out three times. Last activation occurred as soon as the system was recharged after being drained by the previous activation. Seemed really strange to me.

It is a multi-story retirement home. I believe first activation was on 6th floor, then 9th, then 4th (could be wrong on my recollection of the order). Crazy thing was that all locations were in public areas (not private rooms), and aligned within several feet if superimposing the floors in a plan view. All relatively close to stairs.

Maybe a renegade sprinkler activator fiend? All reachable locations, especially the last two. First in a dropped ceiling, the other two particularly accessible in mechanical closets.

 

[cdafd]

what is the static / pump pressure on the system

 

[cdafd]

Scenario

Jockey pump freezes up

Cannot keep system pressurized

Main fire pump comes on and pressures entire system

What is the pressure on the system when the pump is running???

 

[jaymiess]

I think I understand your scenario...

You mean the fire pump pressure when it is running? I don't know I will have to check into that. If it's too high I suppose it can cause sprinklers to activate?

Thanks.

 

[jaymiess]

Oh I see you asked about the static pump pressure on the system. I have photos of the gages in the room where the jockey pump is located so I'll have to check them.

 

[cdafd]

Should have asked I take the main fire pump is on top floor/ roof

What is the static on the system no main pump running

What is the pressure on the system with the main pump running

 

[jaymiess]

The jockey pump and main pump are side-by-side in the cold room on the roof penthouse. I only mentioned the jockey pump because it has smaller diameter pipes that I thought would be more likely to freeze up first.

The fire pump annual inspection paperwork indicates:
Suction pressure gauge: 10 psi (bar)
Discharge pressure gauge: 90 psi (bar)
(I assume these readings were taken with the fire pump running.)

Same inspection paperwork also indicates:
Pump starting pressure from pressure switch in controller: 70 psi (bar)
(Don't know how they got this.)

When I look at my photos (during which the fire pump was not on) my pictures of the main pump gauges appear to indicate a pressure of about 10 psi (barely registering on the gauges).

In my photos there is also a gauge connected to a copper pipe going to the jockey pump pipes, and it reads 70 psi (which matches the 70 psi value reported above).

 

[cdafd]

interesting, not that into pumps, does not seem high, but you do gain some pressure ggoung down each floor

Where does the pump get its water from, a tank on the roof???


still not sure why the heads popped?? there were two in small janitor rooms, where was the first one in a small room or out in the open??


Has a fire sprinkler company come looked at thge system, and given an opinion???

 

[jaymiess]

Yes there is a water tank on the roof.

First head pop was in a laundry room.

Old fire sprinkler company dropped in favor of a new one because they were not responsive during event. They were unable to come up with an explanation either. I don't think the new sprinkler company offered any theories. It has everyone pretty stumped.

 

[chicopee]

If there were ice in the jockey pump totally or partially blocking it, then did the failed sprinkler heads continued to flow or did the water stop dripping because of the ice jam? In cold rooms were no heat is available we always told our clients to put heat strips or have high wattage lamps on the valves. In some of the coldest recesses of old manufacturing plants where these valves were located, we had the clients build heated enclosures.

 

[stookeyfpe]

Someone needs a heater...

 

[jaymiess]

For sure they need to keep pipes from freezing in the room with the fire pump and jockey pump. That's just common sense.

The problem is explaining how ice formation may have caused a sprinkler head to activate in the middle of the building three floors down in a well-heated area. And then this occurred again two more times on the same night.

The theory I proposed to begin this thread was basically me grasping at straws, but I don't know how an ice plug would travel down three floors without melting before causing a clog, or for that matter that this would actually cause a pressure increase that would lead to a sprinkler head activation.

I thought cdafd had a better theory, basically that the jockey pump froze up, thus causing the pressure in the lines to drop enough to cause the fire pump to turn on. However it would still have to be explained exactly how this would cause the sprinkler head(s) to activate.

 

[cdafd]

stookey

so what are the possible reasons the heads popped in what should be lower level heated areas?

 

[stookeyfpe]

CDA:

I haven't got a clue. The problem is we have too many variables and I wasn't asked to investigate it. Things that come to mind on these problems include:

- What's the ASHRAE 50 year extreme design condition for this location?
- NFPA 13 or 13R?
- Is this in the US or a foreign nation? If its in a foreign nation I have no experience with EU sprinkler standards.
- Are any of these areas where the failures occurred protected using an anti-freeze system? Was it maintained?
- Has the NFPA 25 inspection report been reviewed? Do they even have the system inspected?
- Are there exhaust ducts adjacent to the sprinklers that may not be insulated and thus, removed enough heat above the ceiling to cause localized freezing of the sprinkler pipe?
- How did the potable water system perform during this event? Did plumbing pipes break? Why not?
- Were all these accidental activations in a portion of a building that was never very well insulated in the first place?

We can what-if this to death but at the end of the day I don't have enough information.

At a minimum it sounds like certain areas of the building aren't well insulated and that I would employ a good pipe insulation - or - a listed heat trace system that's supervised by the fire alarm system for the suspect areas.

As to the ice plug theory, it's just that.

 

[jaymiess]

Thanks for weighing in stookey.

The purpose of starting this thread was basically to see if anyone had experienced a similar situation, and to possibly brainstorm to come up with a possible scenario or two that could perhaps shed some light on what happened. I would think that's actually one of the main purposes of this forum. Sometimes what-if possibilities are actually helpful. That's usually the way I figure things out actually.

 

[chicopee]

When ice forms, it expands, so instead of splitting the sprinkler steel pipes, the glass bulbs of the sprinkler heads busted first. That's my thinking.

 

[fireguy519345]

"Old service company dropped because they were not responsive" Why were they not responsive? Because payment for services was not on a timely basis? Because they were not allowed to do the required service as per NFPA 25? In the last 2 weeks, I told 2 prospective clients "NO" because of the above reasons.

Water in a sprinkler system is static until the head opens or a pipe breaks. I do not think a traveling ice plug is the problem. But, we have changed heads with no visible damage because piping froze the in the same space.

Is this a wet or dry system? I would check for adequate heat in the activation areas. I would also ask about building security. Vandalism sounds like a possibility