you probably don't need to address this as unless the structural engineer or architect has classified the project as being in an earthquake zone your off the hook...seismic bracing is just ugly..really I feel if the structure fails then let the spkr system fall ... after all what did it do in the world trade centers????
On Mon, Jul 5, 2010 at 11:53 AM, ParsleyConsulting < [email protected]> wrote: > Damien, > > If you look carefully at 9.3.1, NFPA-13 is giving you guidance that > there is no need to follow the requirements of section 9.3 unless the > system is required to be protected from damage from earthquakes. Such a > determination, as was discussed last week, is gained either from section > 1613 of the IBC (or your local equivalent) or the provisions of chapter > 13 of ASCE7-05. Both of those documents develop a "seismic design > category", which establishes the level of seismic protection required, > if any. > > If you're designing a project in seismic design categories C, D, E or F, > you're going to need to follow NFPA-13. Please note that there is a new > section in the annex, A.9.3.2.4, which requires a drop from overhead > into racks to have enough flexibility to accommodate horizontal motion > of at least 5% of the displacement (motion) of the rack. That 5% is to > be measured from the floor to the highest point of connection to the > rack, or the highest point of contact between the drop and the rack. > For example, if the rack is 20'-0" high, and the top of the rack is the > highest point of contact, then the drop would have to accommodate at > least 1'-0" of horizontal motion. > > Branch lines, unless they're larger than 2" in diameter, are not > required to be provided with seismic bracing, so it would be doubtful > that in-rack branch lines would be braced and calculated. Additionally, > the branch lines in-racks are generally supported from the rack > structure itself, so if there is some motion, it's believed the branch > lines would tend to move with the racks, save for the drop, which is > required to have flexibility built into it by virtue of flexible > coupling installation, again, where seismic protection is required. > > Hope that's some clarity. > -- > > 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. > > > > Damien Shannon wrote: > > Dear forum members, > > > > I would really appreciate some input in regards to what people are doing > > (when project is outside of an earthquake zone), in respect to 9.2.1.2 of > > NFPA 2010, in regards to the reference to needing to comply with 9.3 > > (Protection of Piping against damage where subject to Earthquakes). > > > > I typically do not see sway bracing, or clearances between branchlines > and > > rack members. Are people meant to be doing sway bracing calcs for this > and > > complying with all sections of 9.3, or is there and exception that I'm > > missing? > > > > Thank you for any input. > > > > QED Sprinkler Designs, Inc. > > 2836 N. Drake Ave, > > Unit: 1R > > Chicago, IL. 60618 > > Phone: (773) 704 2571 > > Fax: (866) 308 1367 > > > > > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > > > For Technical Assistance, send an email to: [email protected] > > > > To Unsubscribe, send an email > to:[email protected]<to%[email protected]> > > (Put the word unsubscribe in the subject field) > > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected]<to%[email protected]> > (Put the word unsubscribe in the subject field) > -- Tom Poisal, CET _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
