Sharon,
ASCE7-05 does indeed reference NFPA-13, 2002. In providing for seismic
protection for automatic sprinkler systems, ASCE7 establishes that for
seismic design category C, all that is necessary is comply with NFPA-13,
2002. It also references NFPA-13, 2002 in the requirements for
buildings in seismic design categories D-E-F, as it explains that being
in conformance with -13 is a part of what is necessary, along with
additional concerns.
The latest edition of NFPA-13 that the 2005 edition of ASCE7 could have
referenced was the 2002.
In your item 6 you reference bracing and support of mains from the
walls, and support of branch lines from a roof structure as being
exclusive. Unless the branch lines are 2-1/2" or larger they need not
be braced, as the effect of the motion they would encounter in a seismic
event is deemed to be transferred to the mains, and resisted by lateral
bracing. The mains could very well be supported from the walls, and
braced to the walls, while the branch lines are hung from the roof
structure.
This is just my opinion as a member of the NFPA-13 Hanging and Bracing
committee and should not be deemed as anything resembling a formal
interpretation of that standard.
--
PARSLEY CONSULTING
Ken Wagoner, SET
760.745.6181 voice
760.745.0537 fax
[email protected] <mailto:[email protected]> e-mail
www.ParsleyConsulting.com <http://www.ParsleyConsulting.com> website
IMPORTANT NOTICE: This correspondence is not a Formal
Interpretation issued pursuant to NFPA Regulations. Any opinion
expressed is the personal opinion of the author and does not necessarily
represent the official position of the NFPA or its Technical Committees.
In addition, this correspondence is neither intended, nor should it be
relied upon, to provide professional consultation or services.
Sharon Alves wrote:
*This just gets us through the 2002 edition of NFPA 13. The IBC refers
seismic design to ASCE 7 which does not recognize NFPA 13, 2002 edition and
which has additional bracing requirements. *
*6. Bracing is to hold the system fairly rigid so it moves with the
structure that it is attached to. A system that has mains braced and hung
to two exterior walls and the rest of the system attached to the roof
structure will not be able to move, as a unit, with the structure.*
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