LP Gas systems - Grounding, Bonding and lightning

M

María Cristina Bernal

New User
Location
Colombia
Occupation
Electrical Engineer
According to NFPA 58, LP Gas systems do not require lightning protection equipment, grounding and bonding, then How are static electricity hazards and lightning strike risks managed?
 
My neighbor experienced a lightning strike to a gas line first hand, he just happened to be in his basement when it struck, arcing to the termite shield burning a hole in the gas line. It was blowing a flame against the wall, which luckily was block, so he was able to turn off the gas before it caught his house on fire.
 
The pipes inside the house should be bonded to the service.

As the pipe leaves the house, before it enters the dirt, there should be an insulated union so the outside riser does not act as a ground rod.

The underground pipe may be steel or plastic. Either way it should be insulated from the dirt by a coating.

At the propane tank end of things, the tank and fittings are all metal, and are sitting on concrete blocks, in physical contact with the ground.
 
Birken Vogt said:
The pipes inside the house should be bonded to the service.

As the pipe leaves the house, before it enters the dirt, there should be an insulated union so the outside riser does not act as a ground rod.

The underground pipe may be steel or plastic. Either way it should be insulated from the dirt by a coating.

At the propane tank end of things, the tank and fittings are all metal, and are sitting on concrete blocks, in physical contact with the ground.
Click to expand...
Here, the underground pipe is bare copper. The past few years now, they have been using plastic coated copper.
 
Copper is not used much around here so that slipped my mind.

The coating is only for corrosion protection and I am not sure why copper started needing to be coated. Either way it should have an insulating union where it emerges from the ground before it connects to the house piping, which is bonded to the service of course.
 
Birken Vogt said:
Copper is not used much around here so that slipped my mind.

The coating is only for corrosion protection and I am not sure why copper started needing to be coated. Either way it should have an insulating union where it emerges from the ground before it connects to the house piping, which is bonded to the service of course.
Click to expand...
I think the coating is just for identification purposes, it’s been used bare around here for as long as I can remember. At least 50-60 years minimum.
 
Its worth noting that NEC section 250.104 (B) does cover 'Other Metal Piping' If installed in or attached to a building or structure, a metal piping system(s), including gas piping, that is likely to become energized is required to be attached to a equipment grounding or bonding conductor as described in the section. Static electricity hazards and lightning strike risks might fall under "likely to become energized"?
 
Metal gas pipe in the dirt, coated or not, is required to be unbonded to the (grounded) house piping, so that no galvanic circuit is made, which will corrode the gas pipe in the dirt.

I would argue that the risk of corrosion and a gas leak is much worse than the risk of lightning. I would categorize lightning as UNlikely to become energized. It's possible but unlikely.
 
Birken Vogt said:
Metal gas pipe in the dirt, coated or not, is required to be unbonded to the (grounded) house piping, so that no galvanic circuit is made, which will corrode the gas pipe in the dirt.

I would argue that the risk of corrosion and a gas leak is much worse than the risk of lightning. I would categorize lightning as UNlikely to become energized. It's possible but unlikely.
Click to expand...
Tell that to my neighbor! LOL!
 
the code says it must be bonded. but not by who. i don't want anything to do with their explosive gas lines.

tell the gas guy, who bought and installed the gas line, to bond it according to his manufacturer's specifications, and bring the line to our panel for us to land. or install an accessible intersystem bonding termination, and specifically mark a lug for him to land his bonding wire.
 
ptonsparky said:
I have never ever seen an LP pipe line in a residential or agriculture setting with any type of insulating fitting. None. All in this area are copper.
Click to expand...
Around here the last few years has been more common to see them run poly gas piping underground. Is almost always converted to metallic riser out of the ground though.
 
Birken Vogt said:
Metal gas pipe in the dirt, coated or not, is required to be unbonded to the (grounded) house piping, so that no galvanic circuit is made, which will corrode the gas pipe in the dirt.

I would argue that the risk of corrosion and a gas leak is much worse than the risk of lightning. I would categorize lightning as UNlikely to become energized. It's possible but unlikely.
Click to expand...
Dielectric coupling not necessarily stopping a rather direct lightning strike that already jumped hundreds of feet through the air for the main strike.

I will say about 25 years ago I got called to a farmhouse where they had a kitchen fire after a nearby lightning strike. Fire started behind the range, might not even been gas range can't recall anymore, but they had both a copper LP gas line as well as electric range receptacle in place. The thinking was there was arcing between electric and gas connections. I do recall there was no grounding electrode at the house, which I did mention could been a factor in what happened here as they though the lightning strike hit power line somewhere outside and entered the house via power line.
 
You must log in or register to reply here.
Top