Fire alarm NAC circuits

mstrlucky74

Senior Member
Location
NJ
I've come across strobes and horn/strobes speced to be wired alternating circuits..like a/b/a/b ...anyone familiar with this?
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I've come across strobes and horn/strobes speced to be wired alternating circuits..like a/b/a/b ...anyone familiar with this?

It was popular in NYC, or so I've been told. The Port Authority of NY and NJ has added a design guideline for fire alarm systems for the LaGuardia Terminal B project that says you can't lose more than 60% of the notification appliances in a space if there is a circuit failure. There is nothing in NFPA 72, the NYC building code or Appendix Q thereto that requires "A/B" circuiting. It may show up in a specification, or there may be an AHJ who has a "shirt-pocket" rule.
 

mstrlucky74

Senior Member
Location
NJ
It was popular in NYC, or so I've been told. The Port Authority of NY and NJ has added a design guideline for fire alarm systems for the LaGuardia Terminal B project that says you can't lose more than 60% of the notification appliances in a space if there is a circuit failure. There is nothing in NFPA 72, the NYC building code or Appendix Q thereto that requires "A/B" circuiting. It may show up in a specification, or there may be an AHJ who has a "shirt-pocket" rule.

Gad just revisited this thread. It does look like NYC code requires alternating circuits for notification.
 

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  • Pages from FIRE ALARM CABLING NYC CODE.pdf
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gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Gad just revisited this thread. It does look like NYC code requires alternating circuits for notification.

Where did you find your pages? It looks like it's out of the formal wording to amend a code, the clue being that all the words are underlined.
 
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