Smoke detector drop down from ceiling

[Leo]

NFPA72 1999
2-3.4.3* Spot-Type Smoke Detectors.
2-3.4.3.1 Spot-type smoke detectors shall be located on the
ceiling not less than 4 in. (100 mm) from a sidewall to the near
edge or, if on a sidewall, between 4 in. and 12 in. (100 mm and
300 mm) down from the ceiling to the top of the detector.
(Refer to Figure A-2-2.2.1.)

NFPA72 2013
17.7.3.2* Spot-Type Smoke Detectors.
17.7.3.2.1* Spot-type smoke detectors shall be located on the
ceiling or, if on a sidewall, between the ceiling and 12 in.
(300 mm) down from the ceiling to the top of the detector.

Can you explain your Particular situation

[peermoh80]

Thanks for your reply.

at site its a cinema hall having ceiling height of 18.5 mtr from ffl.
at site we fix smoke detector from the celing 3.7 mtr.

our third party saying the same clauses you mentioned and reject the installation.

Pls guide is acceptable by NFPA 72 and how i can convince the third party to get the approval.

i attached the drawing for ref.

Thanks,

[peermoh80]

Hi Mr.Leo,

I found the clause 29.8.4.4 NFPA 2010 "In rooms with open joists or beams, all ceiling-mounted detectors or alarms shall be
located on the bottom of such joists or beams."

As per this i think the installation is correct.

whats you suggestion.

[peermoh80]

[quote="peermoh80"]Hi Mr.Leo,

I found the clause 29.8.4.4 NFPA 2010 "In rooms with open joists or beams, all ceiling-mounted detectors or alarms shall be
located on the bottom of such joists or beams."

As per this i think the installation is correct.

whats you suggestion.[/quot

Hi Mr.Leo,

third party inspector replies with statment below

"Citing section 29.8.4.4 of NFPA 72(2010) is inappropriate. Please note that Chapter 29 of NFPA 72 applies to single and multiple station alarms and not system smoke detectors.

it is important to understand the difference between a smoke detector and a smoke alarm: A smoke detector is part of a fire alarm system, whereas a smoke alarm includes the detection and warning components all in one unit and does not require a control unit for power and supervision. the terms smoke alarm and smoke detector are not interchangeable".

"The definitions as cited in section 3.3.33 of NFPA 72(2010) for ceiling surfaces actually classify the ceiling in Cinema & FEC as Smooth ceiling considering open truss construction and will require to follow the requirements stated in Section 17.7.3.2.1"

please advise what they are saying is correct or not

[peermoh80]

Hi Mr.Leo,

iam realy looking for your answer for the above which i trust only you can expline about the stated issue.

[peermoh80]

Hi guys,

can any one guide me what is the max distance, smoke detector can drop down from the ceiling as per NFPA-72.

as i chek in NFPA its shown only max 300mm height from ceiling if its fix on wall.

pls guide.