Art 501 Cost Differential

[charlie b]

A client is deliberating putting part of a new factory building indoors, or leaving it exposed to the elements. If it is indoors, then the room may wind up being Class I Division 2, or even Division 1. The relative costs will be a consideration in the final decision. Does anyone have a rule of thumb that can be applied here?

Consider, for example, a 100? by 150? room. It has overhead fluorescent lights, receptacles along the walls, and a dozen conduits that serve special equipment from a source outside the room.

1. If the room is CID2, how much more would the electrical material and labor cost, as compared to an unclassified room? (i.e., Half again as much? Twice as much?)
2. If the room is CID1, how much more would the electrical material and labor cost, as compared to an unclassified room?

 

[don_resqcapt19]

Charlie,
I would say 75 to 100% more for Division 2 over non-classified and another 50% over Division 2 to go to Division 1. Most of the additional cost is for the materials, but there is some additional labor also.
Even if it is left out in the open I would expect there would be some Div 2 areas and maybe even some Div 1.

 

[ramsy]

Would ventilation make a difference using engineered plans?
Unclassified areas indoors are permitted with sufficient "ventilation provided" beginning with 511.3(C)(1)(a).

 

[charlie b]

Thanks Don and Ramsy. Regarding 511.3(C)(1)(a), it would not apply. This is a factory that will manufacture electrical components, not a garage.

 

[kwired]

Thanks Don and Ramsy. Regarding 511.3(C)(1)(a), it would not apply. This is a factory that will manufacture electrical components, not a garage.

Ventilation and/or if possible, partitioning off areas that will be classified could make a difference.

 

[kwired]

More than just electrical equipment is worth consideration.

If there is combustible or explosive gases present, the people that work at this plant will have work practices, things not allowed, etc. without special permission or procedures that must be followed, even for maintenance operations.

If you can minimize how much space is classified area it may save lots of daily operations problems too.

 

[charlie b]

Natural gas is used during the process of testing the newly manufactured equipment. There is a "rupture disk" in the gas system. In my view, that makes it at least a CID2 area. So the workers would not be at risk, nor would any special ventilation be of use, unless an overpressure event were to occur.

 

[kwired]

Natural gas is used during the process of testing the newly manufactured equipment. There is a "rupture disk" in the gas system. In my view, that makes it at least a CID2 area. So the workers would not be at risk, nor would any special ventilation be of use, unless an overpressure event were to occur.

Guess I'm not totally sure what you are talking about, but can it be isolated to one area so classification is limited to that area?

 

[don_resqcapt19]

The only way ventilation can be used to change a classification is if there is automatic alarms and in some caes shut down of the electrical equipment in the event of ventalation system failure.

 

[charlie b]

Guess I'm not totally sure what you are talking about, but can it be isolated to one area so classification is limited to that area?

They are testing boxes the size of refrigerators, and many of them at a time. So it's a fairly large area. Items that pass go right into trucks, so there is some advantage of doing it outdoors. But northern weather is another consideration, particularly for the workers.

I am dancing around some of the details, as some of the information is considered confidential to my client.

 

[charlie b]

Followup question: Based on the oversimplified description in post #1, can anyone give me an order of magnitude for the cost per square foot for electrical labor and material, presuming the area is not classified?

 

[ritelec]

Followup question: Based on the oversimplified description in post #1, can anyone give me an order of magnitude for the cost per square foot for electrical labor and material, presuming the area is not classified?

Maybe I'm not following here, but wouldn't a sketchup or something help out with some "ball Park" numbers. I can imagine magnitude but my image of magnitude may be different than yours. What's "just" getting hooked up and where...
Service/Power distribution ??? Nothing for or against Union.............but is it Union labor???

Not the sharpest pencil in the draw here....maybe I'm missing something :blink:

 

[kwired]

Cost per sq. ft. is going to be a lot different for a plant filled with machines than it is for one that has few machines.

Then you also have the occasional equipment that needs a large supply - some places there are several pieces of equipment that need a large supply.

Cost per sq. ft. is also going to be different for a building with 10 ft ceiling vs 30 ft ceiling.

I don't see how you could possibly figure this on a per sq. ft. basis.

 

[Fulthrotl]

They are testing boxes the size of refrigerators, and many of them at a time. So it's a fairly large area. Items that pass go right into trucks, so there is some advantage of doing it outdoors. But northern weather is another consideration, particularly for the workers.

I am dancing around some of the details, as some of the information is considered confidential to my client.

what about a roof similar to a butler building structure, that protects from
some of the weather, while not changing the classification of the occupancy?

the supervision and interlocking of electrical disconnects from the area in
question could play havoc with your process flow, in a supervised ventilation solution.
cutting off all sources of ignition without notice, usually causes process engineers to
scream like a mashed cat.

what you need are some hard numbers on bids for cl1 div1.... so you can see how ugly it can be...
now, sewage treatment plants and bidding and costs are often matters of public record, and they can
be discovered with google.....

i was looking for some information once on a civil engineering matter, and came across
a document by the government agency in charge, listing all the bid amounts of my clients
competition in a project..... the internet is amazing that way... ;-)

as to a multiplier on unclassified vs classified..... if there is a way to put pipe in the ground
in pvc, with appropriate seal offs, that's a huge savings over GRC

is the environment corrosive enough to require OCAL? that's another multiplier on top of
the whole classification issue......

i remember 4' 2 tube cl1 div1 fixtures in a sewage plant, 20 years ago, were over $1k each....

well, current pricing is $840 for this one.......

http://www.magnalight.com/pc-45287-...vision-1-led-light--paint-spray-booth-t6.aspx