Electrical Raceways & Equipment - Seismic Restraints

[SierraJ]

Does any body knows of any easy reference (application guide, manual, etc.) to perform seismic restraint calculations for electrical receways and equipments?

 

[BJC]

Easy -No, there is no easy way, it'a a pain.
B-Line and Unistrut both have approved details for seismic hanger details. The details are signed off by a registered California Structural Engineer. The buidling officials I ahve dealt with accept them.

The details are limited, if they say there good for "X" lbs and/or so many of this size conduit that what you have to do. If you overload them you on your own.
If you bulid a big conduit rack that is not covered by one of the standard details see the phone book under "engineers structural" and get your check book.

One thing I can recommend from experience is NUMBER ( or ohterwise uniquely identify ) and MARK your hangers. Put them in a log book with a sketch. This avoids the problem of someone saying "that hanger over by the water cooler looks like it could use another longitudinal brace" in the mean time someone moved the water cooler. Or you could get an inspector saying that a hanger has to many conduits on it. IT may have, check your log and sketch. It may have had 3 when it went up and there may be 6 on it now.
There was an outfit called Badger Engineering that was making some pretty good fittings that allso offered some engineering assistance but I can't find them at the moment. IF I can get to my card collecton I'll post it.

 

[SierraJ]

BJC,

Thank you very much for your help, I will try to get the B-Line details.

At one moment, I started looking at the SMACNA, used by the mechanical engineers but... I then realized I didn't have that much spare time.

 

[BJC]

SMACNA is a good choice. Many building officials are comfortable with it. Keep the log. IT's not as difficult as I amy have mad it sound, except when you deviate from the "cookbook". Have you ducks in a row and the deviations are managable.

 

[rob46]

SierraJ,

Please review the attached site:

http://www.oshpd.cahwnet.gov/FDD/PreApproval/OPAIndex.pdf

 

[EEJaime]

Both Powerstrut, and B-line have details which are pre-approved by the California Office of Statewide Health and Planning, (OSHPD). These are the most restrictive requirements in the country and are almost universally accepted by AHJ's. In addition there are some systems which are also pre-approved and have details for almost every conceivable application. One such is Tomarco-Isat one of many available at OSHPD's site. Look at

http://www.oshpd.cahwnet.gov/FDD/PreApproval/OPAIndex.pdf

hope that helps.