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Metal Fire Sprinkler Piping

G

globe trekker

Registered User
Joined
Oct 19, 2009
Messages
1,739
Is above ground, metal fire sprinkler piping required to be bonded, as per

NEC 250.104, 2008 Edition, ..or NFPA 13, or both?

If you have a section in NFPA 13, please provide that section or sections.

Thanks!

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The confusion lies in understanding the difference between bonding and grounding. Yes, 250.104 requires the system to be bonded. Don't know where it resides, but somewhere states can't use the sprinkler piping as a grounding electrode. We went through this with some fire inspectors quite a few years back, they were running around requiring buildings to disconnect the bonding means on the sprinkler piping.
 
Any input on where the bonding connection on the sprinkler piping is typically installed?

At the fire riser only, at multiple points throughout the structure, both, other?

Again, .."thanks" to ya'll !

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We typically see it in the riser room, which was part of the problem with the fire inspectors.
 
fatboy,

Please elaborate! Also, does anyone know if there are multiple points of attachment to the

above ground, (metal) fire sprinkler system, or just one?

Any other information regarding the bonding of these complex water systems will be

greatly appreciated! :)

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As part of my OP, I have an existing fire riser in a facility. As part of an addition project to

the (overall) facility, the owners will have to install an additional fire riser right next to the

existing fire riser, because of the low flow calculations. The existing fire riser & associated

sprinkler piping is too small to be able to adequately cover the entire facility (including the

"new" addition). The "new" fire riser piping will be interconnected with the existing one.

I am assuming that the existing fire riser will also require a separate bonding attachment

back to the electrical panel buss bar.

Any thoughts from the audience ?

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You can bond it to building steel if that is closer. It may also allay the fears of a fire inspector if it is not going near the electrical equipment.
 
gfretwell,

Thanks for the input! Right now, I am flying blind (so-to-speak). I do not have

any plans indicating any sort of bonding, or the other requirements associated

with the "new" or existing fire risers. I am performing the due diligence in

researching what is required so that I can communicate with the RDP's on this

subject. Neither the RDP's or the fire sprinkler contractor has submitted any

information regarding Article 250.104.

FWIW, I think this is an interesting topic and discussion!

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we always hit the riser in the sprinkler room. i had a heck of time convincing the city fire marshall here that sprinkler piping shall be bonded. he didn't understand it . when i explained "hot" water as in electrically charged, he got the picture :)
 
take a continuity meter and drop in on either side of the coupling. you'll get dcontinuity. the rubber seals the rolled edge of the pipe, the fitting will make contact, the pipe sections generally make end to end contact. hit the riser in the sprinkler room wirh a bond of appropriate size.
 
Continuity means little, conductivity means everything. Just how much conductivity is there in sprinkler pipes?

Here is something from long ago concerning this issue.

QUESTION: "We are installing a fire sprinkler system in an apartment building using NFPA 13R criteria. The electrical contractor is attempting to place a bonding wire at the base of the sprinkler system riser and connect to the neutral bar in the main electrical fuse panel, then connect to the building ground rod. Can the electrical bonding wire at the base of the fire sprinkler system violate NFPA 13, paragraph 5-14.4.3.5, and what detriment to the fire sprinkler system will result if the electrical bonding is allowed to remain in place?"

ANSWER: In response to your question, we have reviewed NFPA 13, NFPA 13R, and NFPA 70, 1999 editions, as the applicable standards. Our informal interpretation is that using the fire sprinkler system piping as a grounding electrode is prohibited by NFPA 13; however, NFPA 70 requires interior metal piping to be bonded in some situations.

NFPA 13R does not address this issue nor does it refer the user to NFPA 13. However, in good practice the user should refer to NFPA 13 and other applicable standards for guidance. There are two reasons for connecting a conducting wire from the neutral bar of an electrical panel to sprinkler system piping. One is where the sprinkler system is intended to be used as "grounding electrode" for the electrical service. This is prohibited by 13:5-14.4.3.5. The other is where the sprinkler system has the likelihood of becoming energized and "bonding" is necessary to prevent the occurrence of an electrical potential difference between the sprinkler system piping and other conductive material in the building. This bonding requirement is given in NFPA 70, paragraph 250-104©. It is important to note here that if the sprinkler system is not connected to other electrical equipment, conductors, etc., it is unlikely that the piping will become energized; thus bonding is not required. FPN to paragraph c indicates that bonding all piping and metal air ducts within the premises will provide additional safety.

Using the sprinkler system piping as a grounding electrode is prohibited by NFPA 13. This is to prevent degradation of the piping resulting from electrolysis. Bonding the sprinkler system may result in electrolysis and subsequently degradation of the piping only in the presence of stray or leakage currents. Examples of these events include high voltage crossover between high- and low-voltage systems, lightning strikes, voltage induction, and electrical equipment insulation failures. The degree to which the piping will degrade is difficult to predict. The exact effect depends on numerous variables like soil conditions, electrical system integrity, event voltage and duration, etc. Also, there are methods to protect the sprinkler piping from stray currents. For example, installing a dielectric (nonmetallic) fitting between the overhead sprinkler piping and the underground supply piping will prevent stray ground currents from entering the overhead piping. Also, if the dielectric fitting is used, the sprinkler system piping loses its grounding electrode capabilities.

In summary, using the sprinkler system piping as a grounding electrode is prohibited. Bonding the sprinkler system piping is only required when it may become energized.

Personally I do not bond or connect anything to the sprinkler line and will spend hours teaching an inspector just why I don’t.
 
Personally I do not bond or connect anything to the sprinkler line and will spend hours teachingan inspector just why I don’t.
Click to expand...
May I please ask which Article or exception do you cite to not bond the sprinkler piping?

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Don't sprinkler systems usually have electrically connected flow sensors and maybe solenoid valves?

If you you could bond to the EGC going to that equipment.

250.104(B)

The bonding jumper(s) shall be sized in accordance with 250.122, using the rating of the circuit that is likely to energize the piping system(s). The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means.
Click to expand...
 
You can bond it to building steel if that is closer. It may also allay the fears of a fire inspector if it is not going near the electrical equipment.
Click to expand...
As long as the point of connection to the building steel is accessible (RE: Article 250.104, 2008 NEC).

gfretwell,

My concern is the voluminous amounts of rigid steel piping that might become energized

with a lightning strike. Shouldn't the bonding be at the fire riser, or at the fire risers in

my case, ...or should points of bonding be in multiple locations for all of the sprinkler

piping installed ? FWIW, this area of the U.S. has a very high, regular occurrence of

lightning strikes.

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