NFPA 24-2019 Standard for the Installation of Private Fire Service Mains and Their Appurtenances.
10.6.1* Thrust Blocks. Thrust blocks shall be permitted where soil is stable and capable of resisting the anticipated thrust forces. Thrust blocks shall be concrete of a mix not leaner than one part cement, two and one-half parts sand, and five parts stone. Thrust blocks shall be placed between undisturbed earth and the ftting to be restrained and shall be capable of resisting the calculated thrust forces. Wherever possible, thrust blocks shall be located so that the joints are accessible for repair. 10.6.2* Restrained Joint Systems. Private fire service mains using restrained joint systems shall include one or more of the following: (1) Locking mechanical or push-on joints Mechanical joints utilizing setscrew retainer glands (3) Bolted flange joints (4) Pipe clamps and tie rods (5) Other approved methods or devices Sizing Clamps, Rods, Bolts, and Washers. Clamps. Clamps shall have the fllowing dimensions: (1)%in.x2in.(13mmx50mm)for4in.(100mm)to6in. (150 mm) pipe (2)%in.x2Vin.(16mmx65mm)for8in.(200mm)to 10 in. (250 mm) pipe (3)%in.x3in.(16mmx75mm)for12in.(300mm)pipe The diameter of a bolt hole shall be % in. (3 mm) larger than that of the corresponding bolt. Rods. Rods shall be not less than % in. (16 mm) ir diameter. Straight runs on hills shall be restrained as deter- mined by a design professional. 10.8 Isalltion Requirements. 10.8.1 Piping, valves, hydrants, gaskets, and ftings shall be inspected for damage when received and shall be inspected prior to installation. 10.8.2 The tightness of bolted joints shall be verified by the bolt torque or by the method described in the listing informa- tion or manufacturer’s installation instructions. 10.8.3 Pipe, valves, hydrants, and ftings shall be clean and free from intemal debris. 10.
10.9 Backfilling. 10.9.1 Backfill material shall be tamped in layers or in puddles under and around pipes to prevent settlement or lateral move‐ ment and shall contain no ashes, cinders, refuse, organic matter, or other corrosive materials. 10.9.2 Backfill material shall not contain ash, cinders, refuse, organic matter or other corrosive materials. 10.9.3* In the absence of specific guidelines or specifications, the maximum allowable particle size for backfill within 1 ft (300 mm) of the pipe shall not be larger than 1 1 ∕ 2 in. (40 mm). N Nominal pipe sizes of 4 in. (100 mm) or smaller shall not exceed 1 ∕ 2 in. (13 mm) maximum particle size. N Nominal pipe sizes of 6 in. to 12 in. (150 mm to 300 mm) shall not exceed 3 ∕ 4 in. (19 mm) maximum particle size. 10.9.4 Frozen earth shall not be used as backfill material. 10.9.5 In trenches cut through rock, tamped backfill shall be used for at least 6 in. (150 mm) under and around the pipe and for at least 2 ft (600 mm) above the pipe.
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