casualty / other structures permitted to be of Type III, IV and V construction

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casualty

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This is my first visit to this site. I am an inspector and still learning. I have been approached by an electrical company regarding the use of NM in a commercial setting. They referred to 334.10 (3). My question would someone please clarify what is meant by "other structures permitted to be of Type III, IV and V construction?
 
casualty said:
This is my first visit to this site. I am an inspector and still learning. I have been approached by an electrical company regarding the use of NM in a commercial setting. They referred to 334.10 (3). My question would someone please clarify what is meant by "other structures permitted to be of Type III, IV and V construction?
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Type III A ? Mixed/Exterior walls non-combustible,
Interior walls combustible, Roof combustible/ Rating 1(sprinklers installed)
Type III B ? Mixed/Exterior walls non-combustible,
Interior walls combustible, Roof combustible/ Rating 0
Type IV ? Heavy Timber (HT) 8?x*8? or larger
Type V A ? Any Material/Wood, Plastic, Straw/Rating 1(sprinklers installed)
Type V B ? Any Material/Wood,, Plastic,Straw/Rating 0
note: rating could change because table 601 (IBC)

You also need to notice added sections in NEC 2008 300.5(B); 300.9 &
334.12(B)

The interior of the receway installed outside is consider wet location. The wiring within must be rated for wet location. Romex (NM) is not approved for wet locations. Romex is not allowed in wet or dump locations. The inside of the receways (EMT & PVC) installed outdoors are consider wet locations. Open sides porched are considered damp locations.

I hope this helps :)

Adam (kacper)
 
casualty said:
This is my first visit to this site. I am an inspector and still learning. I have been approached by an electrical company regarding the use of NM in a commercial setting. They referred to 334.10 (3). My question would someone please clarify what is meant by "other structures permitted to be of Type III, IV and V construction?
Click to expand...

I think I can help.

Say you where a developer building a large store, as it happens the local building codes would allow you to construct it of wood, (Type V) But for whatever reason you end up building it out of metal and concrete. This is actually pretty common.

So even though the building was built as a type I or II it would have been permitted to be Type III, IV or V.

Under these conditions we could use NM cable ......... of course we still have to keep the NM out of the space above a suspended ceiling in non-dwelling units.
 
casualty, use of nm in hotel/motel?

casualty, use of nm in hotel/motel?

How about in a hotel/motel situation. 334.10 says other structures of Type III, IV,and V.
 
casualty, use of nm in hotel/motel?

casualty, use of nm in hotel/motel?

Would the r-1 be classified as an other structure (type III, IV or V)as stated in 334.10 (3) or is there another section in the electrical code that I am overlooking?
 
You need to understand the building code and the different types of construction in order to completely understand your job as an electrical inspector. What type of construction is declared on the blueprints for the hotel/motel?
 
First I need to apology for posting unfinished respond. It was early in the morning and I did,t have my coffee.
Anyway the occupancy type (motel,hotel) each is R-1 is not the issue . The essence of this article addressed necessity of using raceway in type I and II construction and other structures (please look the definition: ? Structure. That which is built or constructed.?when using conductors Type NM, NMC and NMS.
You can, not run those type of conductors without using a raceways.:)
 
OK let's go over together.

?334.10(3)
Other structures permitted to be of Types III, IV, and V construction except as prohibited in 334.12. Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a
15-minute finish rating as identified in listings of firerated assemblies.? gives us a reference to ? 334.12

334.12(A)(1) Exception:Type NM, NMC, and NMS cable shall be permitted in Type I and II construction when installed within raceways permitted to be installed in Type I and II construction.

The exception is the answer or at least this is how I interpret ate this section.:)
 
Here these quick built hotels "Holiday Inn Express type" are going up everywhere, and these company's will take you to task, we had one inspector who tried to stop NM from being used, and they took him to court in a flash, we had to pipe the elevator shaft area, we had one that had a conference room, so no NM for places of assembly, or any room with a stage, but the rest of it was all NM.

It will all depend upon your local or state building requirements, as to how they classifies these types of buildings, but be ready for a fight if you say no to NM.:)
 
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kacper said:
OK let's go over together.

“334.10(3)
Other structures permitted to be of Types III, IV, and V construction except as prohibited in 334.12. Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a
15-minute finish rating as identified in listings of firerated assemblies.” gives us a reference to – 334.12

334.12(A)(1) Exception:Type NM, NMC, and NMS cable shall be permitted in Type I and II construction when installed within raceways permitted to be installed in Type I and II construction.

The exception is the answer or at least this is how I interpret ate this section.:)
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If the building is required by building code to be of type I or II construction you could still run NM in raceways.

If the building code allows this structure to be of Type III, IV or V but was constructed with with Type I or II methods we can run NM without raceways.

In other words if I could have built the the structure with wood but I chose to build it with steel and concrete I can still run NM in it without raceways. (other then above the suspended ceilings.)
 
kacper said:
That's really suck. All depends on the local jurisdiction and adopted codes, but in no case, if the State approved the NEC 2008 :)
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Even under the 2008 NEC I may run NM concealed without raceways in type I and II buildings if they could have been constructed of Type III, IV or V construction. :)
 
iwire said:
If the building is required by building code to be of type I or II construction you could still run NM in raceways.

If the building code allows this structure to be of Type III, IV or V but was constructed with with Type I or II methods we can run NM without raceways.

In other words if I could have built the the structure with wood but I chose to build it with steel and concrete I can still run NM in it without raceways. (other then above the suspended ceilings.)
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Yes u absolutely right. That is the case:)
And let us not forget obout the added changes in regard to romex: 300.5(B); 300.9 &
334.12(B) The interior of the receway installed outside is consider wet location. The wiring within must be rated for wet location. Romex (NM) is not approved for wet locations. Romex is not allowed in wet or dump locations. The inside of the receways (EMT & PVC) installed outdoors are consider wet locations.
 
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kacper said:
And let us not forget about the added changes in regard to romex: 300.5(B); 300.9 &
334.12(B) The interior of the raceway installed outside is consider wet location. The wiring within must be rated for wet location. Romex (NM) is not approved for wet locations. Romex is not allowed in wet or dump locations. The inside of the raceways (EMT & PVC) installed outdoors are consider wet locations.
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We are pretty darn familiar with the NEC here:), and I will point out that in my opinion it has been against code to run NM in raceways in wet locations for many years the changes where only to make that crystal clear.

The NEC has prohibited NM in wet locations for a long time.

The NEC has required raceways in wet locations to be 'arranged to drain' for quite a while.

If we put those facts together we can assume that the NEC considers the inside of conduits in wet locations to also be wet locations. :)
 
The issue here is that once a type of construction method is declared, then that is simply what it is and no one is going to spend the money on Type I or II construction if they could have met the height and area requirements with Type IIIB or V. It does not make any economical sense to do it that way. I have had architects build a Type IV structure but declare it type V to get around partition wall fire rating requirements. Although it is Type IV, it is actually declared Type V. Most of the time when they figure out the costs, they immediately change the type construction to Type VB anyway.

Interior components also come into play with type of construction. Improperly specified carpeting, drapes, floor & wall coverings and other items can force a type of construction to be downgraded.

The only people who will know what a building "could be" built as would be the architect or the plan reviewer. Many times I get blueprints that are spec's for Type III construction because it is normally allowed but limitations on height and area force the building to be upgraded to a Type I or II.
 
ivsenroute said:
The issue here is that once a type of construction method is declared, then that is simply what it is and no one is going to spend the money on Type I or II construction if they could have met the height and area requirements with Type IIIB or V.
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That is simply not true at all.

Let me use what I know as an example, I work in many large grocery stores, in almost all cases the building code would allow wood construction. However, the reality of it is to build it out of wood with the large open spans that are desired on the sales floor it makes more sense to building the store of metal truss. If it was wood they would need a ton of columns or some very expensive wooden glue lams. Then there is the large amount of equipment that is has to be placed on the roof, try making a wooden 'flat roof' that can support heavy equipment and leave large open spans inside the building.

So even though the code would allow wood, wood will not get the job done.:)


Up until recently we where still wiring these large metal and concrete stores with NM.
 
I am working in S. Florida. The NEC 2008 is in effect only two weeks (officially was adopted October 01, 2209) and I have a most pleasant time talking to people on the subject.
Thank you so much for participating and sharing your opinion.

I would have one more word about romex if u wouldn't mind.

Romex was always and continue to be not permitted for use in the wet locations.
I think they added 300.5 & 300.9 to clarify that not only romex (eg. It used to be a common practice for open porches 334.12(B)(4)to run romex on the exterior of the house ? when supported to the ceiling, without any protection or just in the pvc or emt) but also standard THNN are not listed for wet location and the industry shall use appropriated conductors for such use. Appropriate insulation was the issue.:)
 
Understood, I do see how that happens. Behind the scenes however per the building code an M (mercantile) occupancy such as a grocery store when built as a Type VB construction is limited to 1 story and 9,000 square feet. As soon as you exceed the height or area you either have to change the construction type or use sprinklers and fire separation distances to increase the area of the structure. It does not take much to drop a construction type and just because it has metal trusses for the roof does not automatically make it other than a type V construction. There are a lot of other factors that are involved.

Most Walmarts, Targets, Grocery Stores, Walgreens, CVS, etc are Type IIIB but we rarely see NM cable ever spec'd out because they are open truss design or lots of dropped ceilings. Many are mass walls with masonry block making NM even harder to install.

I am do not disagree with your interpretation, just explaining the construction types situation from another perspective. A recent Turkey Hill Mini-Mart was VB construction, 5,000 square feet and not one piece of NM was spec'd out by the electrical engineer.
 
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