ECN Forum Forums Photo Discussion Forums Photos for General Discussion Fire Sprinklers and Electrical Equipment

I agree with the back flows and PIVs and hooking up the trucks.

The back flows have to do with not contaminating the city water supply.

I still strongly disagree that any sprinkler heads will open like a pressure valve when pump pressure is applied.

I really think you have been mislead.

Bob

That may be Bob, my only real concern is providing a conduit to the PIVs and the DCs

I see that a short "primer" on sprinkler systems is required.

Your "standatd" sprinkler head id set at 165F, and spaced to cover 144 sq. ft. Specific site considerations will result in a closer spacing, and the heads are available in different temp settings from 135 to 190F.

A fire heat plume- one of the standard tests uses a simulated wastebasket full of milk cartons- will very quickly elevate the temperature at the ceiling -over the entire room- WAY above the operating temp of the sprinkler head.

Sprinlker heads are also teated to excessive pressures, both sustained and surges. The idea that the fire pump will cause all the heads to "pop off" is absurd.
Now, there are "deluge" systems, where the heads have no trigering mechanism, but are left open and the pipes 'dry', that have all the heads operate at once. In this case, the water flow is triggered by a separate control. This is a system used in a few unusual situations- not your typical department store.

Different fire departments have differing ideas as to how fires are best fought. One of the indicators of a departments' competence is in the local fire insurance rates. Those who believe in standing off and throwing a lot of water at it have much higher insurance rates.


That a sprinkler head might be capped off for any reason just isn't going to happen- push comes to shove, and we get to move the electric.

Now, some will assert that water is a poor conductor, and that my concerns are unfounded. Others will point out the outside main disconnect that will allow the FD to shut down the power before entry.

Now, what if the sprinkler head were located below the duct? Maybe there is a role to be played in designing areas "outside" of sprinkler coverage. This, of course, flies in the face of a century of desinging sprinklers to cover everything, evenly, all the time. In any event, having the head that close to the duct can't be good for the spray pattern of the head!

As for the bus duct- I don't work on them that often, but here are a couple questions:
- Are 'filler plates' generally made to close off the sides?
- Is it generally possible to change a bus to be "right opening" rather than "left opening?"

This installation also brought up a few more issues, which I will raise in future threads.

[This message has been edited by renosteinke (edited 07-13-2006).]

Interesting comments John,
My understanding of connecting the output of a Fire Appliance pump to a building at a fire-call is merely to "charge" a dry-riser system within the building, this is then connected to a riser pack (2 lengths of hose and a nozzle) taken into the building by the first fire crew, for use, should a fire be found.

I have seen many deluge systems in theaters. The design concept being that if the building goes up in flames, you soak the curtains and everything on stage. I have never heard of pressure activiated sprinkler heads, but, I have heard of them failing. One randomly went off in the lobby of a television studio I was working in a few years back. Even the insurance inspector was surprised.

John,
If you are talking about the ISO ratings that insurance companies use to set rates, I will have to disagree. While the ISO rating looks at a lot of things to arrive at a classifiaction for fire departments, the strategy and tactics used by the department is not part of the rating. About 50% of the ISO rating score is from the water supply that is available to the fire department. The ISO ratings go from Class 10 (no organized fire department) to Class 1. There are only a few (less than 50, I think) Class 1 rated departments in the US.
Don

Mike,
Here, there are often fire department inlets to the sprinkler system so that the fire pump can be used to boost the pressure and flow to the activated heads. Often there will also be a dry riser system in addition to the sprinkler system.
Don

I work in locations that have wet and dry sprinkler zones and a deluge system. I could see cases where a sprinkler could go and result in other heads going, not from heat.

Consider a dry zone near a garage door. The riser has an air over water flapper valve where a given air pressure on top will hold back 4 times (or more) the water pressure. If your compressor fails or you develop a leak that the compressor can't keep up with, the flapper will release. Weak sprinkler heads, perhaps the ones that were leaking air, would now be spraying water.

Some wet zones also have flappers to allow a lower water pressure to hold back a higher pressure water source.

Our deluge systems are usually fired by heat detectors and pull stations mixed on two zones, triggering a solenoid to release the deluge valve There are no sprinkler heads, just flow nozzles.

Any of these flow events drop the pressure in the system more than the low volume jockey pump can make up for. The Jockey pump start pressure is the highest, followed by the electric, and the diesel fire pump being the lowest. Once the electric or diesel fire pump kicks in, the pressure pulse can wreak havoc with weak links in the system. I have seen broken fittings and pressure relief and check valves fail.

Our Fire Department siamese connections are for the fire fighters to connect to our high pressure side as their source. We do use dry connections in the subway though.

Finally, we do periodic testing of portable generators on a load bank. This is usually done just outside a building. One day it started raining so they pulled the gen and load bank just inside the garage door. They didn't notice that they had positioned the load bank directly underneath a sprinkler head. They found out shortly.
Joe

[This message has been edited by JoeTestingEngr (edited 07-13-2006).]

Yeah, ok. This never happens. Sprinkler heads rarely to never fail like your describing. First of all, sprinkler heads are normally UL listed to 175psi. The entire system is pressure tested at 200psi for two hours. FM has found that the chance of a sprinkler head failing is one in 16 million.

A properly designed and maintained sprinkler system will not break fittings, and how exactly does a check valve fail? Even if it did, it wouldn't harm system performance.
Haha, ok. Do load banks reach over 155 degrees f?


As for the actual head in that area, unless its within 3' of an electrical panel, there is no code violation. If that was an electrical closet, then the sprinkler should have a flow switch and a shutoff valve in just in case. There is no other requirements, except that the sprinkler line isn't allowed to run into and out of the room.

Think about it here guys, there is an extremely limited chance of that sprinkler head accidentally going off due to mechanical failure. In a fire situation any damage from water is going to be small potatoes compared to what the fire is going to do; even with electrical components.

[This message has been edited by DerBlitzkrieger (edited 09-09-2006).]

DB, a "load bank" is nothing more than the biggest toaster you'll ever see. Lots of elements, getting red-hot. It is quite possible for an area near a load bank to get too hot.

Of course, if it does.... well, that's what the sprinkler heads are for. There are heads made with temperature ratings as high as 195 degrees.


I.m still not convinced that spraying water - even in the case of a fire- on an exposed high-amperage buss is a good thing. That's why I posted this pic!