ASME B31.9-2020 pdf – Building Services Piping.
935.1 GeneraL
The assembly of piping components, either in a shop or as field erection, shall be done so that the completely erected piping conforms to the requirements of this Code and of the engineering design. For assembly of metallic flange joints with ring-type gaskets, it is recommended that ASME PCC-1 be followed, particularly for pipe NPS 12 and larger.
935.2 BoLting Procedure
935.2.1 ALignment. Flanged joints shall be fitted up so that the gasket contact faces, prior to bolting, bear uniformly on the gasket, and then shall be made up with relatively uniform bolt stress.
935.2.2 Gasket Loading. In bolting gasketed flanged joints, the gasket shall be uniformly compressed in accordance with the design principles applicable to the type of gasket used.
935.2.3 SteeL-to-Iron FLanged Joints. When bolting raised-face steel flanges to flat-face cast iron flanges, care shall be used to prevent damage to the cast iron flanges.
935.2.4 BoLt Engagement. All bolts and nuts shall be fully engaged.
935.3 BeLL and Spigot Joints
935.3.1 Cautked Joints. Caulked bell and spigot joints shall be assembled using oakum and poured lead or other joint compounds suitable for the service. Assembly of cast iron bell and spigot pressure piping shall meet the requirements of ANSI/AWWA C600.
935.3.2 ELastomeric Joints. Bell and spigot joints using elastomeric gaskets shall be assembled in accordance with the manufacturer’s recommendations.
935.4 Threaded Piping
935.4.1 Threading. Dimensions of threaded joints shall conform to the applicable standard listed in Table 926.1. Threads shall be clean and free of breaks and tears.
935.4.2 Joint Compound. Any compound or lubricant used in threaded joints shall be suitable for the service conditions and shall not react unfavorably with either the service fluid or the piping materials.
935.4.3 Seat-WeLded Joints. Threaded joints that are to be seal welded shall be assembled without thread compound.
935.4.4 Backing Off. Backing off of threaded joints to facilitate alignment of the pipe is not permitted.
935.6 FerruLe Bite Joints
Ends of tubing shall be cut square and deburred. No scratches, breaks, or other mars on the outside surface of the tubing at the fitting shall be permitted. In tightening the nut, only sufficient torque shall be used to “bite” lightly and uniformly into the tube.
935.7 Compression Joints
Ends of tubing shall be cut square and deburred. No scratches, breaks, or mars are permitted on the outside of the tube at the fitting.
935.8 Other MechanicaL and Proprietary Joints
Grooved, expanded, rolled, 0-ring, clamp, gland, and other joints permitted by para. 913 shall be assembled in accordance with the manufacturer’s instructions.
935.9 Borositicate GLass Piping
Glass-to-glass connections shall be made with clamp compression-type couplings. Closure pieces should preferably be furnished to exact dimension. If necessary, pipe may be field cut and beaded according to the manufacturer’s instructions. Beaded-to-plain-end connections may be made with couplings specially designed for this purpose. Alignment and support for all glass piping shall be verified and adjusted in accordance with manufacturer’s instructions before joints are tightened.
935.10 Equipment Connections
When connections are made to equipment or strain- sensitive piping components, care should be taken to avoid misalignment, which can introduce undesirable end reactions.
935.11 CoLd Spring
Before assembling joints to be cold sprung, supports, guides, and anchors shall be examined to verify that they will not interfere with desired movement or cause undesired movements. The gap or overlap prior to final assembly shall be checked and corrected if necessary to conform to that shown on the drawing.
935.12 Valve Installation
Installation of valves with the stem below the horizontal axis is not recommended.
935.13 Repair of Defective Work
Joints that leak during test shall be tightened within limits of procedures or manufacturer’s instructions. Do not attempt to tighten leaking joints with pneumatic test pressure on the system.Joints that cannot be safely tightened shall be replaced. Assemblies rejected during examination shall be repaired and reassembled or replaced. Replace any glass piping component that is chipped or scratched.