Seismic requirements for catagory B?

[rbhall]

ASCE 7 13.1.3 states the Component Importance Factor for life safety purposes including sprinkler systems shall have an Ip 0f 1.5. I am requesting the contractor to follow chapter 9 on the NFPA 13. The contractor stated no seicmic is required for a seismic design catagory B. It is my understanding of the ASCE 7 13.1.3 because it's a sprinkler system it's not exempted. I am new to inspecting in Texas and was told an engineer is not required to sign off on the sprinkler drawing as they were in S.C. so I have no one to question other than the contractor which has a Fire Protection Specialist performing the drawing.

 

[cdafd]

Stookey on this forum will hopefully answer your question

Tx requires rme to sign, an engineer is not needed

There are no earthquakes in Tx, just well quakes

 

[cdafd]

http://www.tdi.texas.gov/fire/documents/fmstatsprinkler.pdf

 

[cdafd]

http://www.plumbingengineer.com/june_10/fire.php

 

[stookeyfpe]

Unless you're near El Paso, the remainder of Texas is essentially an SDC A. IBC Chapter 16 (I don't have the code section in front of me and I am about to go to bed) states if the hanger design and installation complies with NFPA 13, the design complies in SDCs A-E. In SDC F everything is considered due to ground acceleration and soil liquefaction.

Certain areas around El Paso are SDC B due to USGS concerns over some relatively dormant faults in the Davis Mountains.

If I didn't answer your question please advise.

 

[rbhall]

I am in a seismic B per approved drawings. To be in compliance with NFPA 13 you must still follow ASCE 7. An Importance Factor (Ip)must be given to all components. Life Safety per ASCE 7 is given an Ip of 1.5 requireing all Life Safety components to be constructed in compliance with ASCE 7. ASCE 7 has no exceptions for for A or B it is still considered seismic regardless if there is never any earh quakes. I am amazed no engineer stamp is required in Texas for Life Safety item such as sprinkler. All it takes is a Fire Protection Specialist? WOW never in South Carolina! Then again in S.C. a UL judgement must be designed by a S.C. engineer. SC will not accept an engineer judgement from Hilti or anyone else. Must be a lisc. S.C. engineer. S.C. is very strick on life safety.

 

[TravisMack]

I could be completely off base, but it was my understanding that for Seismic Design Category A or B, you were not required to provide seismic bracing of the fire sprinkler system. For C and higher, you just follow the criteria in NFPA 13. Just don't forget the maximum loads table that you have to comply with. I have seen many people use 2½" pipe at 40 spacing and say it works because the components are listed for greater loads. But, Sch 10 2½" pipe can only have a seismic load of 301 lbs at 40' spacing. You better have some small lines and a small Cp for that to work.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[rbhall]

Thanks Travis for the post. I think there is a lot of confusion among people that seismic only applies to C or greater and that is because other than what is deemed Life Safety it would not apply. Architectural components do not apply, MEP is exempt however I see no exception in ASCE 7 for sprinkler piping. It does state to follow NFPA 13 and youse not need seismic BRACING but may need restraints. I have ask for someone to tell me what the Ip is, if an engineer says its 1.5 on the sprinkler piping you must provide documentation it was designed in accordance with chapter 9 of the NFPA 13

 

[stookeyfpe]

The following is an analysis I wrote in an ICC document regarding ASCE 7. This information was confirmed by a California registered SE.

903.3.1.1 NFPA 13 sprinkler systems. Where the provisions of this code require that a building or portion thereof be equipped throughout with an automatic sprinkler system in accordance with this section, sprinklers shall be installed throughout in accordance with NFPA 13 except as provided in Section 903.3.1.1.1.

Q1: Do the pipe hanging and support requirements in Chapter 9 of NFPA 13 comply with the requirements in ASCE 7, Minimum Design Loads for Buildings and Other Structures.

A1: Up until the 2007 edition of NFPA 13 (the most current edition), the pipe hanging requirements in NFPA 13 Chapter 9 were only valid in Seismic Design Categories (SDC) A, B and C. In SDC’s D through F, the pipe hanger design needed to be engineered to accommodate the various forces based on ground movement. In the 2007 edition of NFPA 13, the members of NEHRP (National Earthquake Hazard Reduction Program) submitted a series of code changes to the NFPA 13 Chapter 9 technical committee which established prescriptive requirements for hanging and supporting fire protection piping in all SDCs. For seismic bracing of piping, the methods in NFPA 13, Chapter 9 can be used for all SDCs.

These changes in NFPA 13 are now acknowledged in the 2009 IBC. 2009 IBC Section 1613.6.3 states that piping designed in accordance with NFPA 13 meets the requirements of ASCE 7 Section 13.6.8. [9-21]

 

[rbhall]

I agree that NFPA 13 chapter 9 complies with ASCE 7. I guess you may not understand my question. The designer does not show any restraining straps on the beam clamps. How is the designer in compliance with NFPA 13 without the use of restraining straps or branchline restraints? I can't find anywhere in code that exempts him from the use of either. Therefore on my opinion they are not in compliance with chapter 9 of the NFPA 13.

Thanks for your correspondence.

 

[stookeyfpe]

I understand completely. From your message it appears your belief is additional forms of bracing or clamping is required in SDC A or SDC B. That may be true but I haven't reached that conclusion.

 

[rbhall]

I haven't reached a conclusion yet LOL. Just trying to figure it out. I know an engineer with TOLCO and have written him, I will let you know what he says.
Thanks