Sprinkler systems are considered Life Safety devices that must operate after an event. So the 1.5 factor is applied and we get to put in EQ bracing when everyone gets to go home.
I've had the argument with an AHJ over making a sprinkler system require EQ bracing in an existing building when we know that the building didn't take in consideration these new point loads. His response to me what that the buildings capabilities were not my concern, that's the structural engineers problems. As the sprinkler contractor my job was to provide and install the system as required by the code. The requirement of EQ bracing on fire sprinkler systems only is not something the ME or FPE just makes up (well hopefully not in most cases). There is a prescribed method to determine when the bracing is to be required based on several conditions out of the Codes we use every day. We can debate the value, the validity and the ideology behind the direction given per the codes all day long, but if you want it changed, do the homework, submit the paper work and then do the legwork to make the change. Otherwise this becomes a futile debate. Craig L. Prahl, CET Fire Protection Specialist Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 [email protected] http://www.ch2m.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Thom Sent: Friday, July 16, 2010 1:50 PM To: [email protected] Subject: RE: The Seismic Blind Spot Are you all getting on board with all the "New" seismic requirements? Have you figured out that seismic can be everywhere? Have you run into the Seismic Blind Spot yet? What do I mean by Seismic Blind Spot? You know, those jobs, sometimes Gov. and sometimes engineer driven, where the Fire Sprinkler Contractor is the only one doing Seismic? Sometimes if you did the calc or USGS site work "No-one is REQUIRED" to be seismic, and in other cases, yes it is a seismic project, but you're the only one doing it. This is what I call the "Seismic Blind Spot". So what's wrong with either of these? From a $$ point of view maybe nothing. More work installing seismic = more $. From a liability point of view, maybe not so great. What is the purpose of installing Seismic on the Fire Sprinkler system? Survivability? Protection of a "Life Safety" system in the case of an event? What event? What are we trying to help it survive? The only thing Seismic bracing and restraint on a fire sprinkler system is designed to do is improve the survivability of the fire protection system in case of an earthquake event. Not a Hurricane not a Torrnado not a wild fire and not a impact crash of a 747. We are designing for the effects of an earthquake. So is installing Seismic bracing and restraint on a system that is not required useless for every other possible occurrence? Since there are many things that can mimic some or one of the effects seen in an earthquake it would seem there should be some benefit, right? Well if there is always "Some" benefit for every system, why hasn't the 13 hanger and bracing committee just called for seismic everywhere? I believe the answer is multi fold, 1) additional cost. 2)Lack of request for this application. 3)lack of a study showing positive results. Is it dangerous to install seismic on the fire protection systems in a non-seismic designed structure? I think the answer is YES! Let's start with basics. We brace our systems to have them move in harmony with the structure. We provide Flexibility where we know differential movement will most likely occur during an earthquake. We restrain our systems to prevent them from striking the structure or other systems. So how could any of these things be bad, or cause a problem? Bracing our systems to a non-seismic structure can apply point loads to a structure that would not exist, except for our bracing. Point loads which could actually weaken a structure most likely already pushed beyond any design parameters. So the short answer is we could help knock down a structure that is supporting our life safety system. Kind of like hanging a 12" main from a single 8"Z girt. "No you honor, we didn't tell the structural engineer what loads we were applying to his structure or where." Let's look at the flexibility issue. Where is this building going to flex? Well certainly in some of the same places a seismically designed structure will flex, but also in ways and locations that would never happen in a seismically designed structure. So where do we install flexibility? Where will the building move differentially? Anyone? Pick a location, you're probably all right. The most likely answer is "Everywhere! What are the chances that we provided flexibility at all of the locations a structure that's not be seismically designed will flex? A) Not likely B) Very unlikely C) Not possible D) ALL Finally Restraint. A personal favorite of mine. If we are restraining our system from striking a structure or other system, does that really do any good if that structure or system is not itself designed to be restrained from striking our systems? "Now hold still while I hit you!" For Seismic to work, it has to be "Systematic". That is, every system and part of the structure must be part of the solution. Failure of one can cause all to fail. Consequentially installing only one system with seismic design will not save the others and they will take that one system down with them. If the foundation fails, will the structure survive? If the roof collapses will the fire sprinkler system that was hung from it survive? Or the 2nd floor? Installing Seismic only on the fire protection systems is like only putting sprinkler heads in the closets of a building and expecting it to control all fires in that structure. Seismic needs to be a team approach, from the dirt to the sky, otherwise your just pissing into the wind. Even then we are only improving the survivability, not guaranteeing it. TGIF _______________________________________________ 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) _______________________________________________ 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)
