25% rule/N.J.
- Thread starter pridelion
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aelectricalman
Senior Member
- Location
- KY
Re: 25% rule/N.J.
Your question is vague. Are you speaking of smoke detectors? What is the original value? Do you mean original value when the home was build? Please expand. Thanks
Your question is vague. Are you speaking of smoke detectors? What is the original value? Do you mean original value when the home was build? Please expand. Thanks
goldstar
Senior Member
- Location
- New Jersey
- Occupation
- Electrical Contractor
Re: 25% rule/N.J.
I believe this is part of the NJ Uniform Construction Code 5:23-6:32 - Additions:
1) If the area of the addition is 25% or more of the largest floor of the existing building, smoke detectors complying with the building subcode shall be installed throughout the addition and the existing building.
Interpretation : If the floor space of your addition is equivalent to 25% or more of the largest floor of the existing building you will need interconnected smoke detectors in each bedroom, in the common hallway outside the bedroom area, one on each level (one of the bedroom hallway detectors might qualify) including the basement.
I guess what they are insinuating is that if your addition is as large as 25% of the largest floor space it probably isn't a hardship to install smoke detectors throughout the house.
2) If the area of the addition is 5% or more but less than 25% of the floor area of the existing building, hardwired interconnected smoke detectors with battery back-up meeting the requirements of NFPA 72, except as otherwise provided in the building or fire subcode, shall be installed and maintained in each story of the dwelling unit, including the basement.
Interpretation : If the floor space of your addition is equivalent to 5% but less than 25% of the largest floor of the existing building you will need interconnected smoke detectors on each level, including the basement.
I usually install them at a common point of updraft (i.e. at the top of the stairway). This could present a hardship if you are working in an older home where they have plaster walls with wood lath. If you're not working in that area and have to break open walls and ceilings to get wire and boxes installed it becomes a real mess.
I believe this is part of the NJ Uniform Construction Code 5:23-6:32 - Additions:
1) If the area of the addition is 25% or more of the largest floor of the existing building, smoke detectors complying with the building subcode shall be installed throughout the addition and the existing building.
Interpretation : If the floor space of your addition is equivalent to 25% or more of the largest floor of the existing building you will need interconnected smoke detectors in each bedroom, in the common hallway outside the bedroom area, one on each level (one of the bedroom hallway detectors might qualify) including the basement.
I guess what they are insinuating is that if your addition is as large as 25% of the largest floor space it probably isn't a hardship to install smoke detectors throughout the house.
2) If the area of the addition is 5% or more but less than 25% of the floor area of the existing building, hardwired interconnected smoke detectors with battery back-up meeting the requirements of NFPA 72, except as otherwise provided in the building or fire subcode, shall be installed and maintained in each story of the dwelling unit, including the basement.
Interpretation : If the floor space of your addition is equivalent to 5% but less than 25% of the largest floor of the existing building you will need interconnected smoke detectors on each level, including the basement.
I usually install them at a common point of updraft (i.e. at the top of the stairway). This could present a hardship if you are working in an older home where they have plaster walls with wood lath. If you're not working in that area and have to break open walls and ceilings to get wire and boxes installed it becomes a real mess.
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