Battery enclosure for class1 div2 area

What is the Gas Group ?

There's something wrong here!

The only suitable methods of protection will be explosion-proof, Ex 'd', or purge-pressurise, Ex 'p', unless other-rated proprietary certified equipment is available, which is unlikely. Here's why.

http://en.wikipedia.org/wiki/Electrical_Equipment_in_Hazardous_Areas

Which begs the question, "How do you service the batteries without opening the enclosure and risking ingress of a flammable atmosphere into the enclosure?" The question is unanswerable, which is why moving the stored energy in those batteries outside the hazardous area should be seen as the only way forward. And what are those solar cells doing inside a hazardous area? Are they not capable of generating an incendive electrical spark too (rhetorical question)?

Another possibility is that the rating of the hazardous area is so unreasonable and the area so large as to imply that there is a materials containment problem to address before positioning those batteries and panels! If this is true then the matter needs to be addressed before the Factories Inspector's next surprise visit, partly on Health and Safety and partly on economic grounds......

It is perfectly acceptable to service powered equipment in Class 1 Div 2 areas. Class 1 Div 2 is an area where explosive vapors would only be present in an upset condition.

To service the equipment, a "hot work" permit is granted by the area supervisor (typically by verifying the absence of explosive vapors). The box can then be opened safely for maintenance.

Tad

Before there's a

Batteries in themselves should be suitable for I, D, 2 as they do not produce sparks nor surface temperatures under normal operating conditions. First, the hazard must exist during failure or maintenance (the gas) in sufficient concentrations to cause an explosion, then, passing that test you cannot have sparks or surface temperatures above the autoignition temperature of the Group D chemicals. Batteries don't spark unless my wife is helping you by bringing some sandwiches out to the garage on a metal pie pan and sets it atop the battery posts.

<Batteries in themselves should be suitable for I, D, 2 as they do not produce sparks nor surface temperatures under normal operating conditions.>

Eh? They are potentially a source of incendive sparks! What is acceptable in the domestic garage isn't applicable to hazardous areas in a factory, oil and gas platform, petrol station, etc.

I don't like this. I'm moving my box to outside Banklays Bank for safety reasons <splutter>.

. . . . but not during normal operation. One must make a spark or surface temperature above the autoignition point of the gas as a matter of normal operation to be non-compliant. All other protection is a matter of preference and additional safety outside the code. A battery sitting all alone being charged and drawn from does not produce sparks or high surface temperatures if properly applied and installed.

Now, given that, the chances are VERY high a spark can come from improper handling, loose cables, improper selection, etc. Just like most things. Show me proof that a stand alone lead acid battery is disallowed for I, D 2 or Zone 2 and I'll learn something. You can be the teacher ! Hurry because I'm a bit slow . . . . . any . .way.

Is the potential hazardous atomosphere fumes from liquid paper?

I am not sure you can (hydrogen producing batteries, high fault currents, etc). Are your solar panels in the classified area too?, if so they need to be suitably rated (solar panels can produce high fault currents remember). If you have sourced suitably rated solar panels (or separate enclosures to protect them) let me know, as I have never come across any.

You REALLY need to ask an expert on this (or at the very least someone who has the relevant standard in front of them).

No I dont see how this is possible without being very expensive as batteries must be vented during charging. and even if you do this how can you get at the batteries to maintain them? This is the most likley time there could be an accident. Also as others have said where do you ge EX rated solar panels We install hundreds of panels every year and I have never seen ex rated panels.

Try http://www.kellysearch.com/qz-product-7386.html in the UK or http://www.cse-ex.com/, though I think they are Australian based. I know that the later does Ex'e' and Ex'd' enclosures.

I would echo the concerns of the previous guys though. Make sure you talk to whichever manufacturer you choose to see what their advice would be.

My experience of having batteries in any enclosed area where maintenance people go into resulted in the death of a former workmate, he was doing routine maintence on a valve which was enclosed in a room that also had batteries in there as an emergency to operate these valves, they were encased in a proper battery case,the valves isolated pressure water to a hydro power station, this station was run by the national grid, so all the safety hazards would have been addressed, also questions had been asked I believe to the battery manufacturers about ventilation of gasses, however this chap who was a fitter went in with his mate, the fitter always smoked a pipe! they set up all the gear to reach the job,and proceeded to work,then there was an explosion, my old workmate was killed, his mate broke an ankle, but managed to struggle down to the station which was some hundreds of feet below, to raise the alarm. My advice to you therefore if you have to have the batteries in that room, make sure there are more than adequate ventilation fans in there, and have a strict "no smoking" rule in force, my understanding was that the gas was not detected by smelling, therefore it was assumed it was safe and had been for a number of years.

Good answer. Hydrogen has no smell. It also has the lowest spark energy of any flammable gas., like I said.

Original Poster, please get yourself adequately informed as to what you can do and what you can't do with Electrical Equipment in Potentially Explosive Atmospheres, before there's another fatality!

Well, thanks for the comments.

I found some catalog of solar cell panels that are suitable for class 1 div 2. (http://www.solarelectricsupply.com/Solar_Panels/BP-Solar/BP_SX60.html)

also, batteries can be installed in class1 div2 area in an enclosure provided that there some positive pressure/air supply from a safe/unclassified area that will push the gas out. also loss of pressure should be monitored.

but, i didn't come across any existing design, or some real/working photovoltaic system in a hazardous area. solar system is usually located in the safe area. that's why im a little worried there. you see, i am not the one who started the design and the burden was on me. they didn't consider that point in the initial stage.

maybe, my best option is to pray.. awww...

thanks again!!!

<batteries can be installed in class1 div2 area in an enclosure provided that there some positive pressure/air supply from a safe/unclassified area that will push the gas out. also loss of pressure should be monitored.>

Good answer. The solution corresponds to Ex 'p' under the code. The installer must assess the effect of tuning off all power to the circuits when the enclosure is opened, and the need to purge the enclosure for a set period after it is closed again.

What Ex 'p' does is create a miniature safe area within the hazardous area. Opening the enclosure and letting the hazardous atmosphere in has to be properly managed.

<I found some catalog of solar cell panels that are suitable for class 1 div 2. (http://www.solarelectricsupply.com/Solar_Panels/BP-Solar/BP_SX60.html)>

Aha! The junction box is the critical component. Is it Ex 'd' or Ex 'e'? And where is its European certification? What cable glands are to be used in its connections?

Original Poster: if your hazardous areas are large, you have a serious containment problem to address! Do it now, before someone gets ill or gets hurt!!

I would talk to these folks:

http://www.okbebco.com/

Their catalogue is a wealth of information and I'm sure the folks there can help. I agree that purging or X-proof enclosure (X-proof enclosures can be vented) are probably the best way to go for the batteries. The Bebco catalogue also goes into the regulations on the power line conduits etc.

For X-proof boxes you may want to check:

http://www.crouse-hinds.com/

Don't let the other posters scare you. There is a way to do what you want to do safely and following the electrical code. It may be a bit pricey, but certainly feasible. You may want to enlist the aid of the plant electrician or safety engineer, as they would be very familiar with these types of installations. Should be pretty simple, but you need to know the regs!

It sounds like you are in North America. I would be careful about advice from folks across the pond, as safety regulations can be quite different in other countries.

Tad

We work on IEC and other European standards which are generally more strict, so our knowledge of NEC500 and other US standards is a little limited, although there are Hazardous area plants down here that are exclusively American equipment-American standard.

Best you go to the proper people to ask for advice unless you want me to examine part of your plant when it arrives on our shore, still smoking.

Just let us all know what you have been advised, it isn't every day a hazardous area solar system is needed.

In the natural gas production industry, they install solar systems and batteries into Class 1 Div 2 areas all the time. The electronics design and manufacturing company I work for, Rogue Engineering www.rogue-engr.com just completed CSA Class 1 Div 2 certification on a lead acid battery charger we make that is capable of charging a 6V or 12V SLA battery in a Class 1 Div 2 area from a solar panel up to 75 Watts in size.

The enclosure can be pretty much any standard enclosure rated for outdoor use, as long as it has a UL/CSA file number they can look up. A NEMA 4X rating is helpful as well. I know some of our customers use enclosures from Hoffman, Hammond, Bud, etc. You will need to go through the CSA certification and testing process with your electronics installed in the chosen enclosure - not a cheap or quick process at between 5 and 30 thousand dollars. It is by far more cost effective to buy a completed system off the shelf that is certified than get your own system certified unless you are doing a fairly large quantity of installations. If you are doing only a few installations, I would recommend going to a solar system dealer such as Carmanah and having them create a system that meets your needs.

Generally, for low voltage electronic products the main thing they look for is that you have to have a valid method for limiting the current available from the battery and any other power source in case of a short, such as some resistance permanently mounted in series with the battery as part of the battery leads. Proper warning labels are also important, since the equipment cannot be disconnected or serviced while a hazardous atmosphere is present. I'm greatly simplifying things here, since it really is a pretty complicated process to get a product certified for use on a hazardous location, but it definitely is possible.

I've ran into the same problem offshore over the years myself.

I found some fiberglass deck or upright enclosures that are well vented in South Louisiana, and have been using them for years. They can be purchased through API Control System Soultions, Carencro, LA, AutoComm, Lafayette, LA, Automatic Power, New Iberia, LA, C&D Batteries in Beaumont, TX.

You may consider an air purge if available in a vented 4X enclosure if it makes you more comfortable, but as long as you're in Div2 an not Div1, you won't need the air purge. The air purge is my choice as is also cuts down on corrosion. Usually air isn't available in remote locations. We only have instrument gas on remote wellhead structures.

We use a permitting system, gas detection to make sure area is clear and continuous monitoring of the atmosphere. Anything above zero, you can't service the batteries until the atmosphere is clear. Area clear, you're OK.

They are expensive, but are durable and approved for lead acid as well as the spillproof batteries. We'll usually have a 10-24 battery configuration, but the cabinets can be custom made to your specs.

The enclosures must be vented for the hydrogen gasses to escape as you probably already know.

What is your particular location, application. Are you offshore by any chance.

Hope this helps.

I am an I/E Technician, and have been for 20 plus years now, and was on our Area Safety Committee for several years and we beat on this dead horse over and over, and you'll do the same thing until you use some common sense here, which is what we did.

First of all, it is not a hazard until the battery box is opened and the LEL is exceeded in the atmosphere.

You will overheat the batteries in an explosion proof enclosure without an air purge to keep them cool in the summertime.

Don't go to the unnecessary extravagance of using an explosion proof box. Not practical or necessary.

Use the Fiberglass enclosures from Louisiana that I mentioned before. I'm sure you can purchase them elsewhere, but they are UL and USCG approved for use if you are offshore. That's why they are so expensive.

You can also purchase some 316SS vented enclosures. We currently have some here where I work. They are fine too.

Sometimes it is not an issue unless you make it one.

Remember, the batteries are not a hazard unless the enclosure is OPEN and the LEL has been exceeded. Utilize your permitting system.

Use the spillproof batteries, which have only negligable amounts of hydrogen gas release if any. Main thing to remember here is use charge controllers on the PV array so not to over charge the batteries. The system is only as good as your charging system. DO NOT OVERCHARGE Batteries. This is the most common mistake I've seen on battery banks. If you don't over charge, you won't have any problems. Apply corrosion preventive compounds initially. Visual inspections and periodic cleanings should be all you have to do for years to come.

What difference does it make about the enclosure when you have it open to atmosphere. This is where the permitting system comes into play.

You can look at all the regs all you want and find a reason not to install anything but an ex enclosure, but if your using your "Hot Work" permitting system and following the requirements/procedures, you'll be OK.

I saw alot of the same quotations in earlier replies to you pulled from the regs, and it brought back some old memories.

All the answers are right except for the one's who told you this is a problem.

It all depends on which side of the pond you are on. (i.e. NEC or IEC) (i.e CSA or Atex)

The US equivalent (NEC) is more stringent that IEC.