NM cable inside fire walls

[mdshunk]

Are there any prohibited wiring methods inside of fire rated assemblies? Namely, the fire walls between townhouse units.

I roughed an old townhouse that is being rennovated (total gut job), and did the device wiring in the common walls in NM cable. The job was inspected, and passed. A few days later, the inspector had a change of heart. The job was sort of "uninspected". Now I'm being told that the wiring in the fire walls between the units must be MC cable.

I'm not sure why he picked MC over AC, EMT, RMC or whatever. Is he right? Am I not permitted to use type NM cable inside fire walls? For completeness sake, there are no local modifications to the IRC or the NEC. Wiring within fire rated assemblies is not takled about in the "uses permitted" and "uses not permitted" sections of the wiring methods in the 300's of the NEC.

 

[LarryFine]

Re: NM cable inside fire walls

Remember: everyone has a supervisor (or other higher-up).

 

[jimwalker]

Re: NM cable inside fire walls

It is not an nec issue but might be a building code.Ask him to provide you with the code he thinks you violated.I have seen romex in this situation often and it passed.

 

[marc deschenes]

Re: NM cable inside fire walls

I think you should take a look at 334.10 , and annex E.
NM cable can be used in Type 3,4,5 construction

 

[George Stolz]

Re: NM cable inside fire walls

Around here, in certain towns, NM isn't allowed to penetrate firewalls. The solution is a 2' chunk of 2" rigid filled up to 55% in romex, and the remainder with firecaulk.

I have very little clue as to the origins of this practice.

I believe the reason could be that since the jacket of NM would burn away relatively quickly (as compared to a two hour firewall), leaving a porous "ventilation grate" for the fire.

Good luck to the fire trying to get a breath through a 2" straw filled with firecaulk.

 

[pierre]

Re: NM cable inside fire walls

Last week I attended a FireStopping seminar professionally presented and offered by NYS building officials. I learned some of what I didn't know that I did not know . What I mean, is there is so much more to firestopping than I ever imagined. I am also slated to take another class in 2 weeks - which will help in my understanding of how Firestopping actually works.

BTW-one of the topics discussed was, is firestopping required to be installed by a certified firestopping company? Not yet in NYS. But most likely this will be a requirement within 2 years or less. Why? Most installers are laborers or other individuals who are not properly trained in firestopping and in commercial related fires, improper firestopping is the # 1 reason for cause of death.


Tuesday night I was asked a firestopping question at a contractor's meeting. If I had not gone to the firestopping seminar last week, I would have attempted to answer the question. I answered it by saying I was not properly informed, and that the association should have a seminar on firestopping to help answer questions.

 

[don_resqcapt19]

Re: NM cable inside fire walls

Pierre,

improper firestopping is the # 1 reason for cause of death.

Did they provide documentation for that statement?
Don

 

[petersonra]

Re: NM cable inside fire walls

Originally posted by don_resqcapt19:
Pierre,

improper firestopping is the # 1 reason for cause of death.

Did they provide documentation for that statement?
Don

I have a hard time believing this statement. I have always heard it was smoke inhalation.

 

[macmikeman]

Re: NM cable inside fire walls

Given enough idle time and funding, leave it to government to muck up everything. I am not saying that firestopping is not a critical element, and it does need to be carefully and properly installed. But what is next?. Additional certification for installing wire nuts?. Specialized training for people who will specialize in installing florescent lamps? We can no longer simply spray some bleach agent on a mold spot on wall. We have to bring in an environmental remediation outfit to send in a man in a spacesuit and a spray bottle of bleach to do the job. Meanwhile China pounces on us as they conduct their business without all the impediments to progress.

 

[electricmanscott]

Re: NM cable inside fire walls

Originally posted by pierre:

improper fire stopping is the # 1 reason for cause of death.

I have a hard time believing this. I think it is more likely proper fire starting that is the leading cause of death.

This class wasn't sponsored by a fire stopping manufacturer by any chance?

 

[LarryFine]

Re: NM cable inside fire walls

Originally posted by pierre:
I learned some of what I didn't know that I did not know

 

[roger]

Re: NM cable inside fire walls

Larry, not all fire caulks or sealants are intumescent.

Fire stopping doesn't have to be difficult, but it must be a listed assembly or per instructions, and this is the key to doing it right.

Note; the manufacturer will have the assembly information for their products, it can also be found on UL's web site or the Fire Resistance Directory AKA Orange Books

When the rating of the wall or barrier is known, (AIA design) a listed assembly can be picked out and used for the through penetrations.

On our jobs we must have the information of each type of system we use on hand, and are aware that a certain number of penetrations may be opened up and inspected for compliance with the assembly instructions upon the final inspection.

Below is a 1 and 2 hr assembly for different cable types.

System No. W-L-3024

August 06, 2003

F Ratings ? 1 and 2 Hr (See Items 2 and 2A)
T Ratings ? 0, 1/2, 1 and 2 Hr (See Items 2 and 2A)
L Rating At Ambient ? Less Than 1 CFM/sq ft
L Rating At 400 F ? Less Than 1 CFM/sq ft

1. Wall Assembly ? The 1 or 2 hr fire rated gypsum board/stud wall assembly shall be constructed of the materials and in the manner specified in the individual U300 or U400 Series Wall and Partition Designs in the UL Fire Resistance Directory and shall include the following construction features:

A. Studs ? Wall framing may consist of either wood studs or steel channel studs. Wood studs to consist of nom 2 by 4 in. lumber spaced 16 in. OC. Steel studs to be min 2-1/2 in. wide and spaced max 24 in. OC.

B. Gypsum Board* ? 5/8 in. thick, 4 ft wide with square or tapered edges. The gypsum board type, thickness, number of layers, fastener type and sheet orientation shall be as specified in the individual U300 or U400 Series Design in the UL Fire Resistance Directory. Max diam of opening is 2-1/2 in.
The hourly F Rating of the firestop system is equal to the hourly fire rating of the wall assembly in which it is installed.

2. Cables ? One cable to be installed either concentrically or eccentricity within the firestop system. The annular space within the firestop system shall be a min 0 in. (point contact) to a max 1/4 in. Cable to be rigidly supported on both sides of wall assembly. The following types and sizes of cables may be used:

A. Max 200 pair No. 24 AWG (or smaller) copper conductor cable with polyvinyl chloride (PVC) jacketing and insulation. When 200 pair No. 24 AWG telephone cable is used, T Rating is 0 hr. When 50 pair No. 24 AWG telephone cable is used, T Rating is equal to the F rating of the firestop system.

B. Max 3/C No. 2/0 AWG (or smaller) aluminum conductor service entrance cable with PVC insulation and jacketing. When service entrance cable is used, the T Rating is equal to the F Rating of the firestop system.

C. Max 1/C-750 kcmil copper conductor power cable with cross-linked polyethylene (XLPE) insulation and jacketing. When 1/C-750 kcmil cable is used, the T Rating is equal to the F Rating of the firestop system.

D. Max 3/C No. 8 AWG (or smaller) PVC insulated and jacketed nonmetallic sheathed (Romex) cable. When Romex is used, the T Rating is equal to the F Rating of the firestop system.

E. Max RG59/U (or smaller) coaxial cable with fluorinated ethylene insulation and jacketing. When coaxial cable is used, the T Rating is equal to the F Rating of the firestop system.
F. Max 62.5/125 micron fiber optic cable with PVC insulation and jacketing. When fiber optic cable is used, the T Rating is equal to the F Rating of the firestop system.

G. Max 4 pair No. 24 AWG (or smaller) copper conductor data cable with Hylar insulation and jacketing. When data cable is used, the T Rating is equal to the F Rating of the firestop system.

2A. Through-Penetrating Product* ? As an alternate to Item 2, max one through-penetrating product to be installed either concentrically or eccentrically within the firestop system. Through-penetrating product to be rigidly supported on both sides of wall assembly. The following types of through-penetrating products may be used:

A. Max four copper conductors No. 4/0 AWG (or smaller) aluminum or steel Armored Cable+ or Metal-Clad Cable+. When armored or metal-clad cable is used, the T Rating is 1/2 hr.

AFC CABLE SYSTEMS INC

B. Two or more twisted copper conductors No. 6 AWG (or smaller) Power Limited Circuit Cable+ with or without a jacket under a metal armor. When Power Limited Circuit Cable+ is used, the T Rating is 1/2 hr.

AFC CABLE SYSTEMS INC

C. Two or more twisted copper conductors No. 10 AWG (or smaller) Power Limited Fire Alarm Cable+ with or without a jacket under a metal armor. When Power Limited Fire Alarm Cable+ is used, the T Rating is equal to the F Rating of the firestop system.

AFC CABLE SYSTEMS INC

D. Two or more twisted copper conductors No. 12 AWG (or smaller) Non Power Limited Fire Alarm Cable+ with or without a jacket under a metal armor. When Non Power Limited Fire Alarm Cable+ is the T Rating is equal to the F Rating of the firestop system.

AFC CABLE SYSTEMS INC

3. Fill Void or Cavity Material* ? Sealant or Putty ? Min 5/8 in. thickness of fill material installed within annulus, flush with both surfaces of wall assembly. Additional fill material installed such that a min 1/4 in. diam crown is formed around the through-penetrant on both sides of the wall.

SPECIFIED TECHNOLOGIES INC ? SpecSeal Series 100 Sealant or SpecSeal Putty


*Bearing the UL Classification Marking

+Bearing the UL Listing Mark


Roger

[ November 10, 2005, 06:40 PM: Message edited by: roger ]

 

[pierre]

Re: NM cable inside fire walls

Maybe my statement of the deaths due to firestopping was not properly stated (in trying to keep my statements brief), let me try again.

The improper installation of firestopping has lead to the number one reason for cause of death (in commercial buildings, during fires), as improper firestopping permits gases and smoke to travel through the building at very fast rates, usually before the occupants can escape, sometimes even before the notification system is engaged.

There are many issues that need to be dealt with in the construction industry, I am willing to bet the ones with the "squeaky wheel" are addressed first - as a fair warning that others will be dealt with in some future date.
Yes they gave government statistics to the deaths.
No, this was not provided by a firestopping manufacturer.

There are more than 100 fire stopping assemblies, due to the different types of construction.

For those who seem to get so mad, I would bet money that if a family relation was killed in a fire due to someone's ignorance or blatant disregard for some type of installation, you would not be so against some interaction to remedie the situation.

Firestopping has been installed for years, and it would seem to me maybe not so well. Someone has to step in and grab the bull by the horns to help control the installations.
I am not saying that everyone is making improper installations, but I would think we could all agree there are many installations that are not proper.
JMHO!!!

[ November 10, 2005, 07:44 PM: Message edited by: pierre ]