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Piping shall be listed for fire protection service or shall comply with the standards in Table 10.1.1. [24:10.1.1]

Table 10.1.1 Manufacturing Standards for Underground Pipe

Materials and Dimensions Standard
Ductile Iron
Cement Mortar Lining for Ductile Iron Pipe and Fittings for Water AWWA C104
Polyethylene Encasement for Ductile Iron Pipe Systems AWWA C105
Ductile Iron and Gray Iron Fittings, 3 in. Through 48 in., for Water and Other Liquids AWWA C110
Rubber-Gasket Joints for Ductile Iron Pressure Pipe and Fittings AWWA C111
Flanged Ductile Iron Pipe with Ductile Iron or Gray Iron Threaded Flanges AWWA C115
Protective Fusion-Bonded Epoxy Coatings for the Interior and Exterior Surfaces of Ductile-Iron and Gray-Iron Fittings for Water Supply Service AWWA C116
Thickness Design of Ductile Iron Pipe AWWA C150
Ductile Iron Pipe, Centrifugally Cast for Water AWWA C151
Ductile-Iron Compact Fittings for Water Service AWWA C153
Standard for the Installation of Ductile Iron Water Mains and Their Appurtenances AWWA C600
Steel Water Pipe 6 in. and Larger AWWA C200
Coal-Tar Protective Coatings and Linings for Steel Water Pipelines Enamel and Tape — Hot Applied AWWA C203
Cement-Mortar Protective Lining and Coating for Steel Water Pipe 4 in. and Larger — Shop Applied AWWA C205
Field Welding of Steel Water Pipe AWWA C206
Steel Pipe Flanges for Waterworks Service — Sizes 4 in. Through 144 in. AWWA C207
Dimensions for Fabricated Steel Water Pipe Fittings AWWA C208
A Guide for Steel Pipe Design and Installation AWWA M11
Reinforced Concrete Pressure Pipe, Steel-Cylinder Type AWWA C300
Prestressed Concrete Pressure Pipe, Steel-Cylinder Type AWWA C301
Reinforced Concrete Pressure Pipe, Non-Cylinder Type AWWA C302
Reinforced Concrete Pressure Pipe, Steel-Cylinder Type, Pretensioned AWWA C303
Standard for Asbestos-Cement Distribution Pipe, 4 in. Through 16 in., for Water Distribution Systems AWWA C400
Standard for the Selection of Asbestos-Cement Pressure Pipe AWWA C401
Cement-Mortar Lining of Water Pipe Lines 4 in. and Larger — in Place AWWA C602
Standard for the Installation of Asbestos-Cement Water Pipe AWWA C603
Polyvinyl Chloride (PVC) Pressure Pipe, 4 in. Through 12 in., for Water Distribution AWWA C900
Polyvinyl Chloride (PVC) Pressure Pipe, 14 in. Through 48 in., for Water Distribution AWWA C905
Polyethylene (PE) Pressure Pipe and Fittings, 4 in. (100 mm) Through 63 in. (1575 mm) for Water Distribution AWWA C906
Specification for Seamless Copper Tube ASTM B 75
Specification for Seamless Copper Water Tube ASTM B 88
Requirements for Wrought Seamless Copper and Copper-Alloy Tube ASTM B 251

[24: Table 10.1.1]

Steel piping shall not be used for general underground service unless specifically listed for such service. [24:10.1.2]
Where externally coated and wrapped and internally galvanized, steel pipe shall be permitted to be used between the check valve and the outside hose coupling for the fire department connection. [24:10.1.3]
The type and class of pipe for a particular underground installation shall be determined through consideration of the following factors:
  1. Fire resistance of the pipe
  2. Maximum system working pressure
  3. Depth at which the pipe is to be installed
  4. Soil conditions
  5. Corrosion
  6. Susceptibility of pipe to other external loads, including earth loads, installation beneath buildings, and traffic or vehicle loads


Piping, fittings, and other system components shall be rated for the maximum system working pressure to which they are exposed but shall not be rated at less than 150 psi (10 bar). [24:10.1.5]
Unless the requirements of are met, all ferrous metal pipe shall be lined in accordance with the applicable standards in Table 10.1.1. [24:]
Steel pipe utilized in fire department connections and protected in accordance with the requirements of 10.1.3 shall not be required to be internally lined. [24:]
Fittings shall be of an approved type with joints and pressure class ratings compatible with the pipe used. [24: 10.2.1]
Fittings shall meet the standards in Table or shall be in accordance with 10.2.3. [24:]

Table Fittings Materials and Dimensions

Materials and Dimensions Standard
Cast Iron  
Cast Iron Threaded Fittings, Classes 125 and 250 ASME B16.4
Cast Iron Pipe Flanges and Flanged Fittings, Classes 12, 125, and 250 ASME B16.1
Malleable Iron  
Malleable Iron Threaded Fittings, Class 150 and 300 ASME B16.3
Factory-Made Wrought Steel Buttweld Fittings ASME B16.9
Buttwelding Ends ASME B16.25
Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and Elevated Temperatures ASTM A 234
Pipe Flanges and Flanged Fittings, NPS 1/2 Through 24 ASME B16.5
Forged Steel Fittings, Socket Welded and Threaded ASME B16.11
Wrought Copper and Bronze Solder Joint Pressure Fittings ASME B16.22
Cast Bronze Solder Joint Pressure Fittings ASME B16.18

[24: Table]

In addition to the standards in Table, CPVC fittings shall also be in accordance with 10.2.3 and with the portions of the ASTM standards specified in Table that apply to fire protection service. [24:]

Table Specially Listed Fittings Materials and Dimensions

Materials and Dimensions Standard
Chlorinated Polyvinyl Chloride (CPVC) Specification for Schedule 80 CPVC Threaded Fittings ASTM F 437
Specification for Schedule 40 CPVC Socket-Type Fittings ASTM F 438
Specification for Schedule 80 CPVC Socket-Type Fittings ASTM F 439

[24: Table]

Other types of fittings investigated for suitability in automatic sprinkler installations and listed for this service, including, but not limited to, polybutylene, CPVC, and steel differing from that provided in Table, shall be permitted when installed in accordance with their listing limitations, including installation instructions. [24:10.2.3]
Listed fittings shall be permitted for system pressures as specified in their listings, but not less than 150 psi (10 bar). [24:10.2.4]
Joints shall be approved. [24:10.3.1]
All threaded steel pipe and fittings shall have threads cut in accordance with ASME B1.20.1, Pipe Threads, General Purpose (Inch). [24:10.3.2]
Pipes joined with grooved fittings shall be joined by a listed combination of fittings, gaskets, and grooves. [24:10.3.3]
Joints for the connection of copper tube shall be brazed or joined using pressure fittings as specified in Table [24:10.3.4]
Other joining methods listed for this service shall be permitted where installed in accordance with their listing limitations. [24:10.3.5]
Joints shall be assembled by persons familiar with the particular materials being used and in accordance with the manufacturer's instructions and specifications. [24:]
All bolted joint accessories shall be cleaned and thoroughly coated with asphalt or other corrosion-retarding material after installation. [24:]
The depth of cover over water pipes shall be determined by the maximum depth of frost penetration in the locality where the pipe is laid. [24:10.4.1]
The top of the pipe shall be buried not less than 1 ft (0.3 m) below the frost line for the locality. [24:10.4.2]
In those locations where frost is not a factor, the depth of cover shall be not less than 21/2 4 ft (0.8 m) to prevent mechanical damage. [24:10.4.3]
Pipe under driveways shall be buried a minimum of 3 ft (0.9 m). [24:10.4.4]
Pipe under railroad tracks shall be buried at a minimum of 4 ft (1.2 m). [24:10.4.5]
The depth of cover shall be measured from the top of the pipe to finished grade, and due consideration shall always be given to future or final grade and nature of soil. [24:10.4.6]
Where it is impracticable to bury pipe, pipe shall be permitted to be laid aboveground, provided the pipe is protected against freezing and mechanical damage. [24:10.5.1]
Pipe shall be buried below the frost line where entering streams and other bodies of water. [24:10.5.2]
Where pipe is laid in water raceways or shallow streams, care shall be taken that there will be sufficient depth of running water between the pipe and the frost line during all seasons of frost; a safer method is to bury the pipe 1 ft (0.30 m) or more under the bed of the waterway. [24:10.5.3]
Pipe shall be located at a distance from stream banks and embankment walls that prevents danger of freezing through the side of the bank. [24:10.5.4]
Pipe shall not be run under the building except where permitted in 10.6.2 and 10.6.3. [24:10.6.1]
Where approved, pipe shall be permitted to be run under buildings, and special precautions shall be taken, including the following:
  1. Arching the foundation walls over the pipe
  2. Running pipe in covered trenches
  3. Providing valves to isolate sections of pipe under buildings


Fire service mains shall be permitted to enter the building adjacent to the foundation. [24:10.6.3]
The requirements of 10.6.2(2) and 10.6.2(3) shall not apply where fire service mains enter under the building no more than 10 ft (3 m) as measured from the outside edge of the building to the center of the vertical pipe. [24:]
Pipe joints shall not be located under foundation footings. [24:10.6.4]
Piping shall be run at least 1 ft (305 mm) below the bottom of foundations/footers. [24:10.6.5]
The requirements of 10.6.6 shall not apply when piping is sleeved. [24:]
Mains shall be subjected to an evaluation of the following specific loading conditions and protected, if necessary:
  1. Mains running under railroads carrying heavy cargo
  2. Mains running under large piles of heavy commodities
  3. Mains located in areas that subject the main to heavy shock and vibrations


Where it is necessary to join metal pipe with pipe of dissimilar metal, the joint shall be insulated against the passage of an electric current using an approved method. [24:10.6.7]
In no case shall the underground piping be used as a grounding electrode for electrical systems. [24:10.6.8]
The requirement of 10.6.8 shall not preclude the bonding of the underground piping to the lightning protection grounding system as required by NFPA 780 in those cases where lightning protection is provided for the structure. [24:]
Pipes, valves, hydrants, gaskets, and fittings shall be inspected for damage when received and shall be inspected prior to installation. (See Figure 10.10.1.) [24:10.7.1]
The torquing of bolted joints shall be checked. [24:10.7.2]
Pipe, valves, hydrants, and fittings shall be clean inside. [24:10.7.3]
When work is stopped, the open ends of pipe, valves, hydrants, and fittings shall be plugged to prevent stones and foreign materials from entering. [24:10.7.4]
All pipe, fittings, valves, and hydrants shall be carefully lowered into the trench using appropriate equipment and carefully examined for cracks or other defects while suspended above the trench. [24:10.7.5]
Plain ends shall be inspected for signs of damage prior to installation. [24:10.7.6]
Under no circumstances shall water main materials be dropped or dumped. [24:10.7.7]
Pipe shall not be rolled or skidded against other pipe materials. [24:10.7.8]
Pipes shall bear throughout their full length and shall not be supported by the bell ends only or by blocks. [24:10.7.9]
If ground is soft, or of a quicksand nature, special provisions shall be made for supporting pipe. [24:10.7.10]
Valves and fittings used with nonmetallic pipe shall be supported and restrained in accordance with the manufacturer's specifications. [24:10.7.11]
All tees, plugs, caps, bends, reducers, valves, and hydrant branches shall be restrained against movement by using thrust blocks in accordance with 10.8.2 or restrained joint systems in accordance with 10.8.3. [24:]
Piping with fused, threaded, grooved, or welded joints shall not require additional restraining, provided that such joints can pass the hydrostatic test of without shifting of piping or leakage in excess of permitted amounts. [24:]
On steep grades, mains shall be additionally restrained to prevent slipping. [24:]
Pipe shall be restrained at the bottom of a hill and at any turns (lateral or vertical). [24:]
The restraint specified in shall be to natural rock or to suitable piers built on the downhill side of the bell. [24:]
Bell ends shall be installed facing uphill. [24:]
Straight runs on hills shall be restrained as determined by the design engineer. [24:]
Thrust blocks shall be considered satisfactory where soil is suitable for their use. [24:]
Thrust blocks shall be of a concrete mix not leaner than one part cement, two and one-half parts sand, and five parts stone. [24:]
Thrust blocks shall be placed between undisturbed earth and the fitting to be restrained and shall be capable of resisting the calculated thrust forces. [24:]
Wherever possible, thrust blocks shall be placed so that the joints are accessible for repair. [24:]
Fire mains utilizing restrained joint systems shall include one or more of the following:
  1. Locking mechanical or push-on joints
  2. Mechanical joints utilizing setscrew retainer glands
  3. Bolted flange joints
  4. Heat-fused or welded joints
  5. Pipe clamps and tie rods
  6. Threaded or grooved joints
  7. Other approved methods or devices


Clamps shall have the following dimensions:
  1. 1/2 in. × 2 in. (12.7 mm × 50.8 mm) for 4 in. (102 mm) to 6 in. (152 mm) pipe
  2. 5/8 in. × 21/2 in. (15.9 mm × 63.5 mm) for 8 in. (204 mm) to 10 in. (254 mm) pipe
  3. 5/8 in. × 3 in. (15.9 mm × 76.2 mm) for 12 in. (305 mm) pipe


The diameter of a bolt hole shall be 1/16 in. (1.6 mm) larger than that of the corresponding bolts. [24:]
Rods shall be not less than 5/8 in. (15.9 mm) in diameter. [24:]
Table provides numbers of various diameter rods that shall be used for a given pipe size. [24:]

Table Rod Number — Diameter Combinations

Nominal Pipe Size (in.) 5/8 in. (15.9 mm) 3/4 in. (19.1 mm) 7/8 in. (22.2 mm) 1 in. (25.4 mm)
4 2
6 2
8 3 2
10 4 3 2
12 6 4 3 2
14 8 5 4 3
16 10 7 5 4

Note: This table has been derived using pressure of 225 psi (15.5 bar) and design stress of 25,000 psi (172.4 MPa).

[24: Table]

When using bolting rods, the diameter of mechanical joint bolts shall limit the diameter of rods to 3/4 in. (19.1 mm). [24:]
Threaded sections of rods shall not be formed or bent. [24:]
Where using clamps, rods shall be used in pairs for each clamp. [24:]
Assemblies in which a restraint is made by means of two clamps canted on the barrel of the pipe shall be permitted to use one rod per clamp if approved for the specific installation by the authority having jurisdiction. [24:]
Where using combinations of rods, the rods shall be symmetrically spaced. [24:]
Clamp bolts shall have the following diameters:
  1. 5/8 in. (15.9 mm) for pipe 4 in. (102 mm), 6 in. (152 mm), and 8 in. (204 mm)
  2. 3/4 in. (19.1 mm) for 10 in. (254 mm) pipe
  3. 7/8 in. (22.2 mm) for 12 in. (305 mm) pipe


Washers shall be permitted to be cast iron or steel and round or square. [24:]
Cast-iron washers shall have the following dimensions:
  1. 5/8 in. × 3 in. (15.9 mm × 76.2 mm) for 4 in. (102 mm), 6 in. (152 mm), 8 in. (204 mm) and 10 in. (254 mm) pipe
  2. 3/4 in. × 31/2 in (19.1 mm × 88.9 mm) for 12 in. (305 mm) pipe


Steel washers shall have the following dimensions:
  1. 1/2 in. × 3 in. (12.7 mm × 76.2 mm) for 4 in. (102 mm), 6 in. (152 mm), 8 in. (204 mm) and 10 in. (254 mm) pipe
  2. 1/2 in. × 31/2 in (12.7 mm × 88.9 mm) for 12 in. (305 mm) pipe


The diameter of holes shall be 1/8 in. (3.2 mm) larger than that of rods. [24:]
Restraint straps for tees shall have the following dimensions:
  1. 5/8 in. (15.9 mm) thick and 21/2 in. (63.5 mm) wide for 4 in. (102 mm), 6 in. (152 mm), 8 in. (204 mm), and 10 in. (254 mm) pipe
  2. 5/8 in. (15.9 mm) thick and 3 in. (76.2 mm) wide for 12 in. (305 mm) pipe


The diameter of rod holes shall be 1/16 in. (1.6 mm) larger than that of rods. [24:]
Figure and Table shall be used in sizing the restraint straps for both mechanical and push-on joint tee fittings. [24:]

FIGURE Restraint Straps for Tees. [24:Figure]

Table Restraint Straps for Tees

Nominal Pipe Size (in.) A B C D
in. mm in. mm in. mm in. mm
4 121/2 318 101/8 257 21/2 64 13/4 44
6 141/2 368 121/8 308 39/16 90 213/l6 71
8 163/4 425 143/8 365 421/32 118 329/32 99
10 191/16 484 1611/16 424 53/4 146 5 127
12 225/16 567 193/16 487 63/4 171 57/8 149

[24: Table]

The strap shall be 3/4 in. (19.1 mm) thick and 21/2 in. (63.5 mm) wide. [24:]
The strap length shall be the same as dimension A for tee straps as shown in Figure [24:]
The distance between the centers of rod holes shall be the same as dimension B for tee straps as shown in Figure [24:]
Clamps, rods, rod couplings or turnbuckles, bolts, washers, restraint straps, and plug straps shall be of a material that has physical and chemical characteristics that indicate its deterioration under stress can be predicted with reliability. [24:]
After installation, rods, nuts, bolts, washers, clamps, and other restraining devices shall be cleaned and thoroughly coated with a bituminous or other acceptable corrosion-retarding material. [24:]
Backfill shall be tamped in layers or puddled under and around pipes to prevent settlement or lateral movement and shall contain no ashes, cinders, refuse, organic matter, or other corrosive materials. [24:10.9.1]
Rocks shall not be placed in trenches. [24:10.9.2]
Frozen earth shall not be used for backfilling. [24:10.9.3]
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 (0.6 m) above the pipe. [24:10.9.4]
The installing contractor shall be responsible for the following:
  1. Notifying the authority having jurisdiction and the owner's representative of the time and date testing is to be performed
  2. Performing all required acceptance tests
  3. Completing and signing the contractor's material and test certificate (s) shown in Figure 10.10.1.


FIGURE 10.10.1 Sample of Contractor's Material and Test Certificate for Underground Piping. [24: Figure 10.10.1]

Underground piping, from the water supply to the system riser, and lead-in connections to the system riser shall be completely flushed before connection is made to downstream fire protection system piping. [24:]
The flushing operation shall be continued for a sufficient time to ensure thorough cleaning. [24:]
The minimum rate of flow shall be not less than one of the following:
  1. Hydraulically calculated water demand rate of the system, including any hose requirements
  2. *Flow in accordance with Table
  3. Maximum flow rate available to the system under fire conditions


Table Flow Required to Produce a Velocity of 10 ft/sec (3 m/sec) in Pipes

Pipe Size Flow Rate
in. mm gpm L/min
2 51 100 379
21/2 63 150 568
3 76 220 833
4 102 390 1,476
5 127 610 2,309
6 152 880 3,331
8 203 1,560 5,905
10 254 2,440 9,235
12 305 3,520 13,323

[24: Table]

Provision shall be made for the proper disposal of water used for flushing or testing. [24: Table]
All piping and attached appurtenances subjected to system working pressure shall be hydrostatically tested at 200 psi (13.8 bar) or 50 psi (3.5 bar) in excess of the system working pressure, whichever is greater, and shall maintain that pressure ±5 psi (0.35 bar) for 2 hours. [24:]
Pressure loss shall be determined by a drop in gauge pressure or visual leakage. [24:]
The test pressure shall be read from one of the following, located at the lowest elevation of the system or the portion of the system being tested: [24:]
  1. A gauge located at one of the hydrant outlets
  2. A gauge located at the lowest point where no hydrants are provided
The trench shall be backfilled between joints before testing to prevent movement of pipe.
Where required for safety measures presented by the hazards of open trenches, the pipe and joints shall be permitted to be backfilled, provided the installing contractor takes the responsibility for locating and correcting leakage.
Where additional water is added to the system to maintain the test pressures required by, the amount of water shall be measured and shall not exceed the limits of Table, which are based upon the following equation:

U.S. Customary Units:


L = testing allowance (makeup water) [gph (gal/hr)]
S = length of pipe tested (ft)
D = nominal diameter of the pipe (in.)
P = average test pressure during hydrostatic test (gauge psi)

Metric Units:


L = testing allowance (makeup water) (L/hr)
S = length of pipe tested (m)
D = nominal diameter of pipe (mm)
P = average test pressure during the hydrostatic test (kPa)


Table Hydrostatic Testing Allowance at 200 psi (ght/100 ft of Pipe)

Nominal Pipe Diameter
Testing Allowance
2 0.019
4 0.038
6 0.057
8 0.076
10 0.096
12 0.115
14 0.134
16 0.153
18 0.172
20 0.191
24 0.229


(1) For other length, diameters, and pressures, utilize Equation or to determine the appropriate testing allowance.

(2) For test sections that contain various sizes and sections of pipe, the testing allowance is the sum of the testing allowances for each size and section.

[24: Table]

Where required by the authority having jurisdiction, hydrostatic tests shall be permitted to be completed in accordance with the requirements of AWWA C600, AWWA C602, AWWA C603, and AWWA C900. [24:]
Each hydrant shall be fully opened and closed under system water pressure. [24:]
Dry barrel hydrants shall be checked for proper drainage. [24:]
All control valves shall be fully closed and opened under system water pressure to ensure proper operation. [24:]
Where fire pumps are available, the operating tests required by shall be completed with the pumps running. [24:]
The backflow prevention assembly shall be forward flow tested to ensure proper operation. [24:]
The minimum flow rate required by shall be the system demand, including hose stream demand where applicable. [24:]
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