DS 2-8 Earthquake Protection for Water-Based Fire ... - FM Global

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2-8 Earthquake Protection Page 4 FM Global Property Loss Prevention Data Sheets 2. The omission of even a few of the critical components necessary for adequate earthquake protection may result in impairment of the system or substantial water damage. The necessary shutdown of the system to stop further water damage also creates a long-term fire protection system impairment. The recommendations in this data sheet are intended to: (1) greatly improve the likelihood that the fire protection system(s) will remain in working condition after the earthquake, and (2) minimize potential water damage from fire protection system leakage. For each type of fire protection system described in the following sections, completion of all recommendations will maximize the probability of the system performing as intended during an earthquake. In general, recommendations are related to the following seven goals: 1. Bracing piping and equipment to minimize uncontrolled differential movement between these items and the structure(s) to which they are attached. 2. Providing flexibility on piping systems and on other equipment where differential movement between portions of those piping systems or equipment is expected. Except where large differential movement occurs over a short distance, flexible couplings provide sufficient flexibility between portions of sprinkler piping systems where needed. 3. Providing clearance between piping or equipment and structural members, walls, floors, or other objects so that potential damage from impact is minimized. 4. Providing anchorage to minimize potential sliding and/or overturning. 5. Using appropriate types of pipe hangers and sway bracing, properly located and attached to the structure to minimize the potential for pullout. 6. Using appropriate types of piping and pipe-joining methods to minimize potential pipe breaks. 7. Providing fire protection system plans and calculations with proper verification of design, and proper verification that the completed installation is in accordance with the design as well as good installation practices. NOTE: See Section 2.3 for guidance on using other codes and standards to provide earthquake protection of fire protection systems similar to that recommended in this data sheet. 2.2 Protection 2.2.1 Sprinkler Systems, Including In-Rack Sprinkler Systems and Small-Hose Piping Systems 2.2.1.1 Sway Bracing Locations 2.2.1.1.1 Lay out sway bracing locations (a) per Sections 2.2.1.1.2 through 2.2.1.1.5, unless closer spacing is needed based on brace or attachment capacity limits, and (b) so that sway bracing locations will coincide with the structural members to which the sway braces will be attached. 2.2.1.1.2 Brace all sprinkler system risers whether they are single or manifolded type, and regardless of size, in accordance with the following guidelines. A. Provide a four-way sway brace within 2 ft (0.6 m) of the top of the riser as shown in Fig. 1. For risers located on the outside of the building, either Detail A or B of Fig. 1 may be used, with the brace attached to a structural element. When possible, avoid the use of manifolded sway bracing at the top of multiple adjacent risers. If used, limit the manifolded arrangement to two risers, and design bracing to carry the total loads for both risers. B. Provide intermediate four-way sway bracing at an interval not to exceed 40 ft (12.2 m). Where flexible couplings are used, arrange this intermediate four-way sway bracing so a brace is provided within 2 ft (0.6 m) of every other flexible coupling (adding four-way braces if necessary). In multistory buildings, lay out bracing so a four-way brace is provided at each floor having a supply main; a four-way brace is considered to exist when the riser passes through a structural floor, and clearances do not exceed the minimums per Section 2.2.1.5.1. ©2010 Factory Mutual Insurance Company. All rights reserved.
Earthquake Protection 2-8 FM Global Property Loss Prevention Data Sheets Page 5 Fig. 1. Flexible coupling and four-way sway bracing details for riser. NOTE: for risers located outside of buildings, Detail A or B may be used with the bracing attached to a structural element. C. Provide a two-way lateral sway brace within 2 ft (0.6 m) of the end of any horizontal manifold piping longer than 6 ft (1.8 m), or when there is one or more flexible coupling(s) on either the horizontal manifold piping or on the riser stub between the floor and the connection to the horizontal manifold piping. See Fig. 2. 2.2.1.1.3 Brace vertical crossmain or feedmain piping, regardless of size, in accordance with the following guidelines. A. Provide four-way sway bracing at both the top and bottom of the vertical pipe run of 6 ft (1.8 m) or more. Locate each brace on the largest diameter pipe within 2 ft (0.6 m) of the respective piping turn. Provide intermediate four-way sway bracing similar to risers as recommended in Section 2.2.1.1.2(B). B. For vertical pipe runs of less than 6 ft (1.8 m) without bracing provided, flexible couplings should not be present within the vertical pipe run (including the piping turns). If flexible couplings are used or needed to satisfy flexibility recommendations (e.g., for pipe drops) at one or both turns for vertical pipe runs of less than 6 ft (1.8 m), then provide four-way bracing on the largest diameter pipe within 2 ft (0.6 m) of each turn equipped with flexible coupling(s). 2.2.1.1.4 Brace horizontal crossmain or feedmain piping, regardless of size, in accordance with the following guidelines. A. Horizontal changes of direction: Provide crossmain or feedmain piping that has pipe runs of 6 ft (1.8 m) or more adjacent to the change in direction with both lateral and longitudinal sway bracing within 2 ft (0.6 m) of the change of direction. If the diameter of the main reduces at the change of direction, locate ©2010 Factory Mutual Insurance Company. All rights reserved.
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DS 2-8 Earthquake Protection for Water-Based Fire ... - FM Global

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