9.3.2* Couplings

Listed flexible pipe couplings joining grooved end pipe shall be provided as flexure joints to allow individual sections of piping 2¹/₂ in. (65 mm) or larger to move differentially with the individual sections of the building to which it is attached.

Couplings shall be arranged to coincide with structural separations within a building.

Systems having more flexible couplings than required by this section shall be provided with additional sway bracing as required in 9.3.5.5.9.

The flexible couplings shall be installed as follows:

1. *Within 24 in. (600 mm) of the top and bottom of all risers, unless the following provisions are met:
   1. In risers less than 3 ft (900 mm) in length, flexible couplings are permitted to be omitted.
   2. In risers 3 ft to 7 ft (900 mm to 2.1 m) in length, one flexible coupling is adequate.
2. Within 12 in. (300 mm) above and within 24 in. (600 mm) below the floor in multistory buildings
3. On both sides of concrete or masonry walls within 1 ft (300 mm) of the wall surface, unless clearance is provided in accordance with 9.3.4
4. *Within 24 in. (600 mm) of building expansion joints
5. Within 24 in. (600 mm) of the top of drops exceeding 15 ft (4.6 m) in length to portions of systems supplying more than one sprinkler, regardless of pipe size
6. Within 24 in. (600 mm) above and 24 in. (600 mm) below any intermediate points of support for a riser or other vertical pipe

When the flexible coupling below the floor is above the tie-in main to the main supplying that floor, a flexible coupling shall be provided in accordance with one of the following:

1. *On the horizontal portion within 24 in. (600 mm) of the tie-in where the tie-in is horizontal
2. *On the vertical portion of the tie-in where the tie-in incorporates a riser

Flexible couplings for drops to hose lines, rack sprinklers, mezzanines, and freestanding structures shall be installed regardless of pipe sizes as follows:

1. Within 24 in. (600 mm) of the top of the drop
2. Within 24 in. (600 mm) above the uppermost drop support attachment, where drop supports are provided to the structure, rack, or mezzanine
3. Within 24 in. (600 mm) above the bottom of the drop where no additional drop support is provided