Explosion Proof fixture clasification

[GCtony]

I need to write a spec for a couple light fixtures and a light switch for a small exterior structure that will give shelter from the weather while the people fuel vehicles. (gas) The building is somewhat enclosed on three sides, the open side has a large overhang 10' above grade that you would park the vehicle under while fueling. Kind of like a car port but three sides have walls that run from 18" off the ground to the roof so it will have good ventalation. (I think it looks like a goat barn) This structure will be built around an existing gas pump. When complete the pump will be under this shelter.

When researching "Explosion Proof" light fixtures and switches, different UL clasifications are mentioned. Class 1, Div. 1 and 2. They also mention Class 2, div. 1 and 2. I looked at the UL website that was pretty much worthless and a search under NFPA was just as helpful. I found a good page from OSHA that did a pretty good job explaining it to me but left me with even more questions. Hazardous (Classified) Locations

Quote:

Hazardous locations are classified in three ways by the National Electrical Code: TYPE, CONDITION, and NATURE.

There are three types of hazardous conditions: Class I - gas and vapor, Class II - dust, and Class III - fibers and flyings.

There are two kinds of hazardous conditions: Division 1 - normal, and Division 2 - abnormal.

And finally, there is the nature of the hazardous substance . . . where we find Groups A, B, C, and D in Class I locations, and, in Class II locations: Groups E, F, and G.

Now for my questions:

1) Am I correct in understanding that a gas pump area as described above would be Class 1 - Div. 2 - D

2) When I specify a light fixture and light switch, am I correct in specing "... required to be Class 1 Div. 2 explosion proof" ?

3) What is the difference between "vapor proof" and "explosion proof"?

4) These fixtures will be under cover so will they need to be moisture resistent along with conduit?

What did I miss? Anything special that needs to happen with raceways, wiring methods? NEC code section I should referance?

For the Sparky's, is there such a thing as a simple incandecent light fixture, Class 1 Div 2D that is also suitable for oudoor use? When I called the supply house, I got the "WTH are you talking about" silence from the sales expert.

For what it's worth; I can't call the friendly folks over at the building department and this project will not be inspected by our local building department. I may try to find an independent electrical inspector or engineer to have a look at it once the electrical contractor completes his work.

Thanks in advance for your help!

 

[cda]

Sounds like close to indoor dispensing per the fire code, will look at what that says

 

[fireguy]

"For the Sparky's, is there such a thing as a simple incandecent light fixture, Class 1 Div 2D that is also suitable for oudoor use? When I called the supply house, I got the "WTH are you talking about" silence from the sales expert."

Emergency and exit lights are available for "damp locations" Are incandecents available with that rating?

 

[Msradell]

Here's a listing of a bunch of Hubble, fixtures for Class I Div 2 areas: Hubbell Industrial Lighting : Products : Hazardous Class 1, Division 2 Cooper and many others also make them. They are not cheap to say the least. I worked in a chemical plant or everything was Class I electrically so any electrical project was very expensive.

 

[GCtony]

Thank you all! It sounds like I'm correct with Class 1 - D2

CDA, "Sounds like close to indoor dispensing per the fire code, will look at what that says" I think this is open to opinion, Personally I don't see how a build up for vapor would be probable. However, if there were a spill, obviously the chances increase for a build up of vapor, possibly collecting higher in the structure. The "shed" is fully open on one side and the other three sides are open at the bottom.

What section in the fire code should I be looking at? From what I have read, I don't see that it would change Class or division.

 

[mark handler]

Google

 

[cda]

Thank you all! It sounds like I'm correct with Class 1 - D2CDA, "Sounds like close to indoor dispensing per the fire code, will look at what that says" I think this is open to opinion, Personally I don't see how a build up for vapor would be probable. However, if there were a spill, obviously the chances increase for a build up of vapor, possibly collecting higher in the structure. The "shed" is fully open on one side and the other three sides are open at the bottom.

What section in the fire code should I be looking at? From what I have read, I don't see that it would change Class or division.

cannot speak to the electrical side, but 2201.4 IFC 2009 thought it use to say more, does refer you to nfpa 30A

Have not had to deal with an inside operation in years.

2201.5 does refer you to section 605 IFc nfpa 70 and nfpa 30a

 

[chris kennedy]

Quote:Hazardous locations are classified in three ways by the National Electrical Code: TYPE, CONDITION, and NATURE.

Thats an OSHA quote? The NEC doesn't classify locations, it tells us how to wire them. From the NECHB commentary to 500.5;

The NEC does not classify specific Class I, II, and III locations.NFPA technical committees and the American Petroleum

Institute (API), among other organizations with

experience and expertise in working with flammable liquids,

gases, vapors, dusts, fibers and flyings inherent to a process

or present under abnormal conditions of operation, determine

the parameters, distances, and degrees of hazard associated

with classified locations. Some of this information

has been extracted from other NFPA and API documents and

is included in Articles 511 through 517 of the Code.

In some facilities, an expert or team of experts, which

may include a process engineer, a mechanical engineer, a

safety engineer, and operations personnel, will use the information

developed in those NFPA standards and apply it to

their specific equipment and process and, depending on the

materials and physical equipment and locations (for example,

possible leaks at flanges, machinery seals), decide on

the area classification, and produce the hazardous area diagram.

See the commentary for 500.4(A). Common sense

and good judgment must prevail in classifying an area that is

likely to become hazardous and in determining those portions

of the premises to be classified Division 1 or Division 2.

 

[rnapier]

While it is true that the NEC does not generally classify a location article 514 Motor Fuel Dispensing Facilities applies to this situation. From the tables 514.3 I think you are not in a class 1 location but over a Class 1 location:

514.7 Wiring and Equipment Above Class I Locations.

Wiring and equipment above the Class I locations as classified in 514.3 shall comply with 511.7.

511.7 Wiring and Equipment Installed Above Class I Locations .7 Wiring and Equipment Installed Above Class I Locations.

(A) Wiring in Spaces Above Class I Locations Wiring in Spaces Above Class I Locations.

(1) Fixed Wiring Above Class I Locations. All fixed wiring above Class I locations shall be in metal raceways, rigid nonmetallic conduit, electrical nonmetallic tubing, flexible metal conduit, liquidtight flexible metal conduit, or liquidtight flexible nonmetallic conduit, or shall be Type MC, AC, MI, manufactured wiring systems, or PLTC cable in accordance with Article 725, or Type TC cable or Type ITC cable in accordance with Article 727. Cellular metal floor raceways or cellular concrete floor raceways shall be permitted to be used only for supplying ceiling outlets or extensions to the area below the floor, but such raceways shall have no connections leading into or through any Class I location above the floor.

(2) Pendant. For pendants, flexible cord suitable for the type of service and listed for hard usage shall be used.

(B) Electrical Equipment Installed Above Class I Locations Electrical Equipment Installed Above Class I Locations.

(1) Fixed Electrical Equipment. Electrical equipment in a fixed position shall be located above the level of any defined Class I location or shall be identified for the location.

(a) ArcingEquipment.Equipmentthatislessthan3.7m (12 ft) above the floor level and that may produce arcs,sparks, or particles of hot metal, such as cutouts, switches, charging panels, generators, motors, or other equipment (excluding receptacles, lamps, and lampholders) having make-and-break or sliding contacts, shall be of the totally enclosed type or constructed so as to prevent the escape of sparks or hot metal particles.

(b) Fixed Lighting. Lamps and lampholders for fixed lighting that is located over lanes through which vehicles are commonly driven or that may otherwise be exposed to physical damage shall be located not less than 3.7 m (12 ft) above floor level, unless of the totally enclosed type or constructed so as to prevent escape of sparks or hot metal particles.

I hope this will help.

 

[rnapier]

Aparently yellow is not a good color to highlight in. I'll try again with out highlights.

b) Fixed Lighting. Lamps and lampholders for fixed lighting that is located over lanes through which vehicles are commonly driven or that may otherwise be exposed to physical damage shall be located not less than 3.7 m (12 ft) above floor level, unless of the totally enclosed type or constructed so as to prevent escape of sparks or hot metal particles.

 

[GCtony]

Aparently yellow is not a good color to highlight in. I'll try again with out highlights.b) Fixed Lighting. Lamps and lampholders for fixed lighting that is located over lanes through which vehicles are commonly driven or that may otherwise be exposed to physical damage shall be located not less than 3.7 m (12 ft) above floor level, unless of the totally enclosed type or constructed so as to prevent escape of sparks or hot metal particles.

I can't meet the 12' requirement. My light fixtures will be roughly 8' off the ground so I will need to have the class 1 "explosion proof" fixtures. Same with my light switch as 511.7a.

Thanks again to all for your help.

 

[rnapier]

I can't meet the 12' requirement. My light fixtures will be roughly 8' off the ground so I will need to have the class 1 "explosion proof" fixtures. Same with my light switch as 511.7a.Thanks again to all for your help.

The switch does not have to be a class 1 type if it is above the class 1 area and you can use the different cable and conduit methods in 511.7A as long as they do not enter the class 1 location which is 18" off the floor and around the pump. The ceiling fixture does not have to be class 1 but only "totally enclosed type or constructed so as to prevent escape of sparks or hot metal particles."