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

Earthquake Protection 2-8
FM Global Property Loss Prevention Data Sheets Page 41
plain-end fittings (one-piece devices into which pipe ends are inserted and held in place by set screws that
have a torque-indicating means to ensure proper torque has been applied) are acceptable for use in areas
where earthquake protection is needed.
2.2.1.8 Type, Attachment, and Locations of Hangers
2.2.1.8.1 Adhere to the hanger guidelines in Data Sheet 2-0, Installation Guidelines for Automatic Sprinklers,
with the following exceptions:
A. Do not use powder-driven fasteners to attach hangers to the building structure.
B. Provide hangers of the type that resist upward vertical movement at the following locations (note that
for very long armovers, hangers in addition to those recommended below will be needed when normal
hanger spacing rules apply):
1. On all armovers to vertical pipe drops that supply more than one sprinkler, regardless of the length
of the armover, located within 2 ft (0.6 m) of the drop.
2. On all armovers greater than 2 ft (0.6 m) long that supply one sprinkler, located within 2 ft (0.6 m)
of the drop (see Fig. 21).
C. Provide all C-clamp hangers with retaining straps to minimize the potential that the C-clamp will slip
off the structural member.
D. Provide hangers on branch lines arranged to prevent the pipe from bouncing upward at the following
locations.
1. At every other hanger on gridded branch lines.
2. At the last hanger on dead-end branch lines, including outrigger lines on gridded systems.
E. To minimize potential damage from impact, ensure the hanger closest to any upright sprinkler that is
located within 2 in. (50 mm) both horizontally and vertically of a structural or nonstructural element is a type
that resists upward vertical movement.
F. Provide hangers for in-rack sprinkler piping of a type that resists upward vertical pipe movement. Provide
no more than 1 ⁄ 2 in. (13 mm) of space between the top of the pipe and the hanger’s point of vertical
resistance. Provide positive mechanical attachment to the rack structure that provides resistance to vertical
movement and does not allow the hanger to slip sideways off the point of attachment. Provide retaining
straps on all C-clamps.
2.2.1.9 Pipe Material
2.2.1.9.1 Do not use nonmetallic pipe in aboveground installations.
2.2.2 Standpipes
2.2.2.1 Seismic Considerations for Standpipes
2.2.2.1.1 Treat standpipes the same as sprinkler system risers with regard to sway bracing, flexibility, and
clearance.
2.2.2.1.2 When hose outlets are fed from pipe that penetrates walls or floors, provide flexibility, clearance
around the piping, and clearance between the piping and walls the same as for sprinkler pipe.
2.2.3 Water-Spray Systems
2.2.3.1 Seismic Considerations for Water-Spray Systems
2.2.3.1.1 In general, treat water-spray systems the same as sprinkler systems with regard to sway bracing,
flexibility, and clearance.
2.2.3.1.2 Use special approaches for sway bracing design and attachment to the equipment or structure
when necessary based on the nature of the particular system and the equipment being protected by the
water-spray system.
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