Sprinkler Systems

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augie47

augie47

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This has been discussed in the past and I doubt there have been any changes but perhaps some clarifications in more recent Codes.
From reading a number of past threads it seems clear that the Fire Sprinkler Systems Codes do not allow sprinkler system piping to be used "for grounding".
Several folks have taken the position that as an interior piping it must be bonded.
I had been under the impression that the slip fitting unions used on many systems isolate the individual section but I have also been told that is incorrect.
It seems to me "bonding" the system to the electrical service was be no different electrically from connecting to it as a grounding electrode.

Anybody shed new light on this ?
 
ActionDave said:
I have never bonded a sprinkler line. I have never been asked to bond a sprinkler line. I don't see any reason to, they are tied to the water main and hanging off the metal roof framing so they are bonded enough.
Click to expand...

250.104 requires it to be bonded.

We usually do it beside the domestic water supply.
 
This is from the 2013 NFPA 13 Sprinkler Code

A.10.6.8.1 While the use of the underground fire protectionpiping as the grounding electrode for the building is prohibited,
NFPA 70 requires that all metallic piping systems be
bonded and grounded to disperse stray electrical currents.
Therefore, the fire protection piping will be bonded to other
metallic systems and grounded, but the electrical system will
need an additional ground for its operation.
 
RICK NAPIER said:
This is from the 2013 NFPA 13 Sprinkler Code

A.10.6.8.1 While the use of the underground fire protectionpiping as the grounding electrode for the building is prohibited,
NFPA 70 requires that all metallic piping systems be
bonded and grounded to disperse stray electrical currents.
Therefore, the fire protection piping will be bonded to other
metallic systems and grounded, but the electrical system will
need an additional ground for its operation.
Click to expand...
I can see where that requirement may be misunderstood and some think you don't bond anything on the fire protection system.

Next question is do they put an isolating fitting on there to lessen the electrode effect of the underground piping like they do on metal gas piping? If not it will still perform as an electrode.
 
RICK NAPIER said:
This is from the 2013 NFPA 13 Sprinkler Code

A.10.6.8.1 While the use of the underground fire protectionpiping as the grounding electrode for the building is prohibited,
NFPA 70 requires that all metallic piping systems be
bonded and grounded to disperse stray electrical currents.
Therefore, the fire protection piping will be bonded to other
metallic systems and grounded, but the electrical system will
need an additional ground for its operation.
Click to expand...
That has always been my understanding and I've heard all sorts of "whys" but if its in the earth and you bond it, you end up with the same electrical configuration as if you connected it as a grounding electrode so it makes no sense.
 
augie47 said:
That has always been my understanding and I've heard all sorts of "whys" but if its in the earth and you bond it, you end up with the same electrical configuration as if you connected it as a grounding electrode so it makes no sense.
Click to expand...
Even if you don't directly bond it - if it is attached to building steel it will be bonded via the attachment and will still become a fairly effective electrode.
 
agreed. That's why I was on a fruitless case to understand "why" :) One of the earlier sprinkler Codes sated "not to be used as a ground"..and I thought perhaps for installation/repair personnel
they did not want someone using it as an equipment grounding path.
It appears the be one of those "cause the book says so" rules.
 
augie47 said:
agreed. That's why I was on a fruitless case to understand "why" :) One of the earlier sprinkler Codes sated "not to be used as a ground"..and I thought perhaps for installation/repair personnel
they did not want someone using it as an equipment grounding path.
It appears the be one of those "cause the book says so" rules.
Click to expand...
Probably means don't ground your SDS's to a sprinkler pipe, or run a bonding/grounding conductor to sprinkler piping that is otherwise permitted to be run to a water pipe.
 
augie47 said:
This has been discussed in the past and I doubt there have been any changes but perhaps some clarifications in more recent Codes.
From reading a number of past threads it seems clear that the Fire Sprinkler Systems Codes do not allow sprinkler system piping to be used "for grounding".
Several folks have taken the position that as an interior piping it must be bonded.
I had been under the impression that the slip fitting unions used on many systems isolate the individual section but I have also been told that is incorrect.
It seems to me "bonding" the system to the electrical service was be no different electrically from connecting to it as a grounding electrode.

Anybody shed new light on this ?
Click to expand...

If they are Victaulic-style grooved fittings then the pipe is electrically discontinuous. It's debatable as to how good a path the water in the pipe provides back to the incoming service. Sprinkler water is some of the worst stuff you can come in contact with. It's stagnant, so all kinds of crap and dissolved and suspended solids accumulate.
 
I believe there are three reasons for the code as written. First, often the underground piping a poor conductor either due to a plastic line up to the point of the riser or the coating on ductile iron being non-conductive. Second, fitters should not be exposed to fault currents while servicing a line. There is potential for hazardous voltage on the line either during a fault or because of improper use of the grounding system as a return path. With that said imagine a situation where a fitter pulls a line apart in the ground to repair it and then becomes part of a circuit. Third is the use of cathodic protection for corrosion control. Those systems that provide corrosion protection of the line do not work properly if the structure (metal pipe) being protected is grounded . Again, the coating of ductile iron and fittings is not supposed to be conductive which is why holiday testing is performed prior to burring a metal line being cathodically protected. Those systems being cathodically protected are required to be electrically isolated at the first flange via a flange isolation kit. Bonding is just to ensure that an OCP device will trip if the above ground piping becomes energized. Generally we provide 120V to the flow switch for the water flow alarm and use the equipment grounding conductor ran with that circuit to bond the riser.
 
gadfly56 said:
The fittings are typically fully painted, and no one is scraping the paint off to maintain good electrical contact. The pipe is discontinuous and only the fittings provide a path, such as it is, from one pipe to another.
Click to expand...

The note at the bottom of the chart says the fittings can be galvanized or painted.
 
I never quite understood this, doesn't the sprinkler main coming from the street connect to the same water main in the street that provides domestic water? Aren't they already connected?
 
infinity said:
I never quite understood this, doesn't the sprinkler main coming from the street connect to the same water main in the street that provides domestic water? Aren't they already connected?
Click to expand...

Often not electrically continuous due to the non-metallic products in use.

For instance both the domestic and the sprinkler lines may run in metal all the way back to the street main but the street main itself could be non conductive.

For me this is like the worrying about driving one rod or two. Just do it and move on. All it generally takes is a bonding jumper a few feet long between the domestic water and the sprinkler line.

In a steel building with the sprinkler lines hanging on metal hangers I really don't see it making any difference at all, but we do have to comply with the rules. :)
 
iwire said:
Often not electrically continuous due to the non-metallic products in use.

For instance both the domestic and the sprinkler lines may run in metal all the way back to the street main but the street main itself could be non conductive.

For me this is like the worrying about driving one rod or two. Just do it and move on. All it generally takes is a bonding jumper a few feet long between the domestic water and the sprinkler line.

In a steel building with the sprinkler lines hanging on metal hangers I really don't see it making any difference at all, but we do have to comply with the rules. :)
Click to expand...
Absolutely correct. If the sprinkler system is to be isolated then the installers must use isolation fittings or else it will naturally find some connections here and there to items already bonded to the electrical system - especially in the situation of steel building and metallic piping supports.
 
luckylerado said:
I believe there are three reasons for the code as written. First, often the underground piping a poor conductor either due to a plastic line up to the point of the riser or the coating on ductile iron being non-conductive. Second, fitters should not be exposed to fault currents while servicing a line. There is potential for hazardous voltage on the line either during a fault or because of improper use of the grounding system as a return path. With that said imagine a situation where a fitter pulls a line apart in the ground to repair it and then becomes part of a circuit. Third is the use of cathodic protection for corrosion control. Those systems that provide corrosion protection of the line do not work properly if the structure (metal pipe) being protected is grounded . Again, the coating of ductile iron and fittings is not supposed to be conductive which is why holiday testing is performed prior to burring a metal line being cathodically protected. Those systems being cathodically protected are required to be electrically isolated at the first flange via a flange isolation kit. Bonding is just to ensure that an OCP device will trip if the above ground piping becomes energized. Generally we provide 120V to the flow switch for the water flow alarm and use the equipment grounding conductor ran with that circuit to bond the riser.
Click to expand...
Cathodic protection makes sense to isolate, the other items mentioned would also be true for the usual domestic water supply.
 
iwire said:
The note at the bottom of the chart says the fittings can be galvanized or painted.
Click to expand...

The next job my old company uses galvanized fittings on will be the first. In nine years I never saw that happen. I don't think they even stocked galvanized fittings.
 
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