4.25 Car Stacking/Lift Systems

Reference: NFPA 13, 2002 edition; 2007 CBC Section 903.3.1.1

Purpose: To establish requirements for sprinkler protection of car stackers not specifically addressed in NFPA 13.

Parking garage areas containing car stackers shall be protected by an automatic wet-pipe sprinkler system designed to Extra Hazard Group 1. In addition, non-extended coverage standard sidewall sprinklers listed for Ordinary Hazard shall be provided under each parking level, including the bottom level if the stacker is provided with a pit. Each sidewall sprinkler shall cover an area of 80 sq. ft or less.
The area of application my be reduced from the required 2500 sq. ft. to as low as 1500 sq. ft. if:
1) 1-hour fire rated walls are provided to separate the car stacker areas from the standard parking stalls,
2) The car stacker areas are divided up into 1500 sq. ft. areas via 1-hour fire rated walls, and
3) One-hour fire rated walls are provided to separate the car stacker areas from any other areas in the garage.
One-hour fired rated walls are not required in the driveway areas. For the hydraulic calculation, flow from all sprinklers, upright or pendent sprinklers at ceiling and all sidewall sprinklers at all levels, located in the area of application shall be included in the calculation.

Note:
For a high-rise building, car stacker sprinkler systems will cause the secondary water supply capacity to increase. For water supply and secondary water supply capacity purposes, the system is to be considered as an Ordinary Hazard System. The secondary water supply shall be designed for largest car stacking sprinkler system demand plus a hose allowance of 250 gpm for 60 minutes. If the available city mainflow at 20 psi is not adequate to provide requirements, the secondary water supply becomes the primary water supply. For this case, the secondary/primary water supply capacity must meet the above requirements and the requirements specified in NFPA 13 and 14.

For low-rise building, if the city main can not provide the required flow at 20 psi, a primary water supply tank and fire pump must be provided. The capacity of the tank shall meet the above requirements and the requirements of NFPA 13 and 14.