Are sprinkler systems required to use earthquake bracing?

Questions about Georgia Codes and Standards

Are sprinkler systems required to use earthquake bracing?

Postby Blackstone on Fri Nov 21, 2008 1:11 pm

While the 2000 IBC, Section 1621.3.10.1 essentially indicates that if the design force and displacement per NFPA 13, when multiplied by a factor of 1.4, exceeds that determined by the IBC, then the NFPA criteria shall override that required by the IBC, the more fundamental question in Georgia is whether the Building Code even requires fire sprinkler piping to be seismically protected. Once it is established that it would be required, then the applicable NFPA or IBC seismic design considerations are needed.

2000 IBC, Section 1621.1.1.1 concerns applicability for seismic restraints, and has provisions that would exempt fire sprinkler components from the architectural, mechanical & electrical seismic design requirements if the Component Importance Factor (Ip) is 1.0. Section 1621.1.6 lists these factors, and Life Safety components that are required to function after an earthquake receive a factor of 1.5.

Life Safety components expected to function after an earthquake in Georgia would be Fire Walls/Barriers/Doors, Elevator shutdown, Hazardous Materials containment systems, systems that are part of a Life Safety Evaluation required by 2000 LSC, Section (i.e. Assembly Occupancies with an Occupant Load over 6000) in accordance with Section, and similar Life Safety features not dependent on factors outside the control of the Building and Fire Codes.

Fire sprinkler systems dependent on a water supply, in which utilities in Georgia have not had to specifically design to withstand seismic forces, can not be readily expected to function after an earthquake. This would place fire sprinkler systems in the ‘All other components’ category since they could not be fully expected, nor thereby required, to function after an earthquake, and thus the applicable Ip would be 1.0. Since the 2000 IBC, Section 1621.1.1.1 would exempt this component in most cases, plus the fact that due to the very low probability and low occurrence of earthquakes in Georgia (and the cost vs. the benefit is not worth it), it basically determines that seismic bracing on fire sprinkler piping is not required. The 2000 IBC does not specifically indicate anywhere that a fire sprinkler system is one of the life safety systems that shall be designed to operate after an earthquake (fire barriers, haz-mat containment, etc. could and should be). O.C.G.A. indicates 'Fire protection sprinkler system' means an integrated system of overhead and underground piping designed in accordance with fire protection engineering standards. The installation includes one or more automatic water supplies. And if the entire fire protection sprinkler system is not designed for seismic resistance (i.e. the underground utility water supply is not seismically designed), nowhere is it said seismically restraining only a portion is adequate.

Life Safety components that could reasonably be expected to function after an earthquake, should be and are required to do so. Fire Barriers and similar Life Safety components could reasonably be expected to function after an earthquake, for their design is not dependent on influences outside of the control of the AHJ, owner, designer, etc. Life Safety systems that depend on an extremely critical influence such as the very water supply providing the life blood of the sprinkler system, which is not designed to the same seismic conditions as the system, nor under the control of AHJ, owner, designer, etc., is a folly at best as the likelihood of this ‘weakest link’ breaking during the event is similar to that of the system breaking, making the effort to only seismically restrain the sprinkler piping ‘portion’ of the system almost worthless, possibly deceptive, with the benefit clearly outweighing the cost at least as far as Georgia is concerned.

Reductions in Building construction requirements due to the building being fully sprinklered are indeed often used. The sprinkler protection provides an equivalency to the code requirements based upon the potential for a fire, not for the potential of earthquakes, meteors, riots, plane crashes, etc., and although these may be the cause of the fire, statistics indicate construction designed to withstand all possible scenarios is more costly than the derived benefit. If it is a mild earthquake, small meteor, ineffective riot, or a small plane that crashes, and then a fire ensues, then the probability is that the system will survive and perform – larger catastrophes will turn all preparations into an effort in futility.

States where statistics have indicated the likelihood, and severity, of an earthquake to be so great, and the loss of life so insurmountable, have determined the derived benefit outweighs the cost by many factors. Therefore not only the construction, but the infrastructure, has been designed to withstand the earthquake influences to the degree of protection that probability, and cost, have established. Georgia just does not appear to be one of those states that typically considers earthquake protection to be this cost effective. However, the 2000 LSC, Section earthquake factor consideration is an example where the potential for loss of life could be so great (6000 + people in one area), that Georgia would normally require the effects of an earthquake be considered in the Life Safety Evaluation, which could feasibly influence some of the sprinkler trade-offs since the water supply could not be relied on as readily.

Requiring the sprinkler piping portion of the system to be seismically restrained does not provide any additional life safety benefit if the entire ‘system’ (e.g. sprinkler and utility piping) is not designed likewise, and doing so throughout Georgia is impractical. In the individual case of seismic restraint of sprinkler piping, per the 2003 IFC, Section 104.8, the requirement for seismically restraining sprinkler piping due to earthquakes as required by NFPA 13 (2002), Section is not required. An exception to this statement would be certain critical occupancies (hospitals, 911 centers, etc.) located in the very small far northern portion of the State (see seismic maps and the IBC seismic section for more), and of course the 6000+ occupant load large assemblies per the LSC...
We find consulations, we learn tricks with which we deceive ourselves, but the essential thing - the way - we do not find. Listen to the river.

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