How to ground a fiberglass tank??

[rrodgers1]

Working in the oil field we run across these fiberglass tanks which hold produced water. I understand there isn't any conductance in fiberglass. What it is we are needing to do is ground the fluid inside the tank to bleed off the generated static. I am looking for any common practices or suggestions on how to make this happen.

My thought is to put a water pipe clamp on all (3) piping entries at the bottom of the tank and tying them back to the ground grid. My thought is that any fluid in the bottom of the tanks would also sit inside the piping with the grounded pipe clamp. Thus grounding the fluid inside the tank.

 

[George Stolz]

As far as the NEC goes, the closest match to your application that comes to mind is 680.26(C), where a 9 square inch electrode in contact with pool water is considered sufficient to bond pool water to the equipotential bonding grid of the pool. Sight unseen, sounds like your idea would serve it's purpose.

 

[petersonra]

Working in the oil field we run across these fiberglass tanks which hold produced water. I understand there isn't any conductance in fiberglass. What it is we are needing to do is ground the fluid inside the tank to bleed off the generated static. I am looking for any common practices or suggestions on how to make this happen.

My first thought is who told you to do this? They should provide an engineering drawing showing how it is supposed to be done.

There is normally no good reason to do something like this, so if it needs doing it must be for some specific purpose, which would seem to require someone with the appropriate experience and knowledge to determine just how it should be done.

There normally is not much in the way of static to bleed off of water at all. It is just too conductive.

In any case, if the piping coming in is metallic, they are generally a pretty effective ground connection. I doubt that putting a wire on it is going to make it any better. If there actually is static to bleed off, your best bet is probably to run the grounding wires you propose adding to a local grounding electrode instead of back to some remote GES. You need to reduce the potential at this point with respect to ground at this point and not with respect to some remote point.

 

[GoldDigger]

My first thought is who told you to do this? They should provide an engineering drawing showing how it is supposed to be done.

There is normally no good reason to do something like this, so if it needs doing it must be for some specific purpose, which would seem to require someone with the appropriate experience and knowledge to determine just how it should be done.

There normally is not much in the way of static to bleed off of water at all. It is just too conductive.

+1
The requirement for bonding the water in a hot tub or pool is based on a line voltage source of current which can provide a sufficient amperage to hold a voltage difference despite the conductivity of the water. Normal static electricity sources do not have that current capacity.
However, if you are pumping fluid which is itself carrying a charge, you could end up with a fairly high available current, and it would not fit the model of static electricity that we are familiar with from daily experience. (Probably does not apply in the OP's situation, but it is interesting to think about. )

 

[petersonra]

+1
The requirement for bonding the water in a hot tub or pool is based on a line voltage source of current which can provide a sufficient amperage to hold a voltage difference despite the conductivity of the water. Normal static electricity sources do not have that current capacity.
However, if you are pumping fluid which is itself carrying a charge, you could end up with a fairly high available current, and it would not fit the model of static electricity that we are familiar with from daily experience. (Probably does not apply in the OP's situation, but it is interesting to think about. )

Water is typically too conductive to build up a static charge unless it is fairly high purity, like 5-10 megohm-cm and being pumped through plastic or plastic lined pipes. There are some fairly common techniques to dissipate this kind of static build up that most piping or instrument engineers would know how to implement. Usually it is done because the static is interfering with certain kinds of instruments like pH or ORP.

Since the OP suggested the pipes are conductive, it seems unlikely that static could build up.

Therefore, it suggests something else is going on here rather than simple static build up.

There is no static electricity involved in a pool. The equipotential bonding required is for step potential.

 

[weressl]

Working in the oil field we run across these fiberglass tanks which hold produced water. I understand there isn't any conductance in fiberglass. What it is we are needing to do is ground the fluid inside the tank to bleed off the generated static. I am looking for any common practices or suggestions on how to make this happen.

My thought is to put a water pipe clamp on all (3) piping entries at the bottom of the tank and tying them back to the ground grid. My thought is that any fluid in the bottom of the tanks would also sit inside the piping with the grounded pipe clamp. Thus grounding the fluid inside the tank.

As others pointed out there would be no need for grounding if it holds water.

Materials that would be a concern for static buildup and that are flammable can not be stored in non-metallic vessels mainly because of other NFPA Standards. Having said that manufacturers of fiberglass vessels can embed grounding wires in the layers of the vessel during production and extend those for outside connections at placement. This will prevent static charge buildup if low conductivity fluids are stirred in the vessel or static buildup due to material charged into the vessel.

 

[mgookin]

Working in the oil field we run across these fiberglass tanks which hold produced water. ....

My guess is this is not pure water, but water/ petrol or water/ methane. He wants to bond the contents to an EGC. Make sense or am I reading this wrong? How does it work in a gas station? Is there an electrode in the tank? Or just bonding of everything that enters the tank as he is suggesting?

 

[kwired]

My guess is this is not pure water, but water/ petrol or water/ methane. He wants to bond the contents to an EGC. Make sense or am I reading this wrong? How does it work in a gas station? Is there an electrode in the tank? Or just bonding of everything that enters the tank as he is suggesting?

Lazlo did mention that flammable material can not be stored in non metallic vessels. Most of the piping is also fiberglass so we don't have any natural electrode from piping either. But almost all underground fuel tanks these days are fiberglass, but probably have conductive material in the fiberglass for this reason, and I would guess the piping is constructed similarly.

 

[rrodgers1]

Water is typically too conductive to build up a static charge unless it is fairly high purity, like 5-10 megohm-cm and being pumped through plastic or plastic lined pipes. There are some fairly common techniques to dissipate this kind of static build up that most piping or instrument engineers would know how to implement. Usually it is done because the static is interfering with certain kinds of instruments like pH or ORP.

Since the OP suggested the pipes are conductive, it seems unlikely that static could build up.

Therefore, it suggests something else is going on here rather than simple static build up.

There is no static electricity involved in a pool. The equipotential bonding required is for step potential.

The underground plumbing is poly pipe. Where it turns up and is above grade it is now black pipe plumbing.

 

[kwired]

I would say you need some kind of electrode inside the tank.

 

[rrodgers1]

My guess is this is not pure water, but water/ petrol or water/ methane. He wants to bond the contents to an EGC. Make sense or am I reading this wrong? How does it work in a gas station? Is there an electrode in the tank? Or just bonding of everything that enters the tank as he is suggesting?

you are reading this right. All we are trying to do is bond the fluid to the EGC. The fluid is produced water, or commonly referred to as "Salt water". this is the water that is separated from the oil once it reaches the surface. It gets separated and put into its own holding tank. the tank/vessel is constructed of fiberglass. have to believe that these vessels meet all laws and requirement do in part they are installed on every well location on average of 2-fiberglass tanks per well. The company that I am working for operates over 300 wells, that is 600 fiberglass tanks, and this is just 1 of many oil producers in the state.

 

[JDBrown]

you are reading this right. All we are trying to do is bond the fluid to the EGC. The fluid is produced water, or commonly referred to as "Salt water". this is the water that is separated from the oil once it reaches the surface. It gets separated and put into its own holding tank. the tank/vessel is constructed of fiberglass. have to believe that these vessels meet all laws and requirement do in part they are installed on every well location on average of 2-fiberglass tanks per well. The company that I am working for operates over 300 wells, that is 600 fiberglass tanks, and this is just 1 of many oil producers in the state.

In that case, a check of how the existing tanks are grounded and a phone call to the tank manufacturer's engineering department should have you well on your way.

 

[jcassity]

a braided copper electrode dangling down into the container at the vent which then transitions out to the ground field via #2 flex or whatever should be a decent recommendation from my desk. Oh, and lets not forget ot impose exothermic omni directional cad welds with inspection wells as well.

somebody said "we are going to soon be pulling chains behind our cars to get an earth ground",,,,, LOL

 

[weressl]

a braided copper electrode dangling down into the container at the vent which then transitions out to the ground field via #2 flex or whatever should be a decent recommendation from my desk. Oh, and lets not forget ot impose exothermic omni directional cad welds with inspection wells as well.

somebody said "we are going to soon be pulling chains behind our cars to get an earth ground",,,,, LOL

Why do you think they have fiberglass tank? Perhaps because the material is interacting with metals.

 

[GoldDigger]

OK, I guess we need to put an insulating protective coating around the ground electrode.

Tapatalk...

 

[broadgage]

If the tank contains ONLY water, then as others post, water is too conductive to accumalate or hold a static charge and grounding is pointless.

As however the tank is for water that has seen seperated from oil, I would consider that under some circumstances, that a mixture of oil and water could be present. Under such conditions static electricity could ignite the oil or vapour with most unfortunate results.

I would ground all metallic fittings, and also place within the tank a grounded metal mesh that covers most of the bottom of the tank, and at least one side.
A grounded mesh or electrode that does not reach the bottom of the tank could be dangerous, if oil is pumped into the tank it could build up a significant static charge until it reaches the mesh or electrode, when a spark could occur.
Water and oil are both very corrosive and the mesh should be made of stainless steel.

I would suggest that the grounding connections be of substantial construction in the interest of mechanical robustness, not current carrying capacity as the current is minute.

 

[jcassity]

back on page 1 i kept want to say water is an insulator (which it is),,, but figured i might get smacked around since we all know what we mean already

 

[broadgage]

Very pure water, unlikely to be found outside of a lab is a fairly good insulator, though not as good as glass, rubber, PVC and other materials used for electrical insulation.

Clean but not especialy pure water, such as most drinking water, is a very poor conductor but still can conduct enough current to be dangerous, hence the advice not to touch electrical equipment with wet hands.

Salty water such as sea water is a moderatly good conductor, though nothing like as good as copper, aluminium and other metals employed as conductors.

 

[tek9]

4 Copper rods in the tank each one connected to each other,4ground rods outside,buried in concrete,a ufer then 40mm bare copper in the concrete or soil at a 12'' depth back to the MEN,or MBJ to you Muricans is what oilfield sparkys tell me they do in OZ the middle east and Canaduh

 

[mgookin]

... is what oilfield sparkys tell me they do in OZ the middle east and Canaduh

Being from Flory-duh that makes me feel good :happyyes: