Inspection Procedures Plumbing and Mechanical Part-3

Plumbing and storm piping :
Section 306.2 continued
•Please be advised that in some cases the material manufacturer has more stringent requirements than the code and must be followed. Manufacturers such as Charlotte Pipe have their own piping installation manual which contains many specific requirements which are not addressed in the code. ***
Plumbing and storm inspections cont:
IPC Section 306.2.1 Overexcavation
•Overexcavationis a common problem and if not addressed results in serious problems with the finished plumbing system. ***
•The code requires the overexcavatedpart of the trench to be backfilled with sand or fine gravel placed in layers not greater than 6 inches in depth and such backfill shall be compacted after each placement. Please be advised that it doesn’t take much bedding instability to affect minimum piping pitch requirements of 1/8thand 1/4 inch per foot.
•IPC Section 306.2.2 Rock removal. Where rock is encountered in the trenching, the rock shall be removed to not less than three inches below the installation level of the bottom of the pipe. The trench shall be backfilled with sand and tamped.
•IPC Section 306.2.3 Soft load-bearing materials. Stabilization shall be achieved by overexcavatingnot less than two pipe diameters and backfilling to installation level of the bottom of the pipe with fine gravel, crushed stone or a concrete foundation.
Plumbing and storm piping Cont :
IPC Section 306.3 Backfilling
•Shall be free from discarded construction materials and debris. Loose earth free from rocks, broken concrete, and frozen chunks shall be placed in the trench in six inch layers and tamped in place until the crown of the pipe is covered by twelve inches of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be brought up evenly on both sides of the pipe so pipe remains aligned. Many times piping manufacturer’s and job specifications have stricter requirements than code minimums.
•“Backfilling continued
•Correct bedding and backfilling are extremely important. If the piping is installed on unstable or unsuitable material the problems will only be compounded when backfilling takes place. As referenced in the previous slide #21 the piping has minimum pitch and it doesn’t take much to cause the incorrectly bedded piping to become flat or reverse pitched. If the underground piping is incorrectly installed the whole plumbing system will be compromised.
•IPC Section 306.4 Tunneling
•Where pipe is to be installed by tunneling, jacking or a combination of both, the pipe shall be protected from damage during installation and from subsequent uneven loading. Where earth tunnels are used, adequate supporting structures shall be provided to prevent future or caving.
•IPC Section 307 Structural Safety
•Section 307.1 General
•While performing plumbing installations any part of the building that must be changed or replaced shall be left in a safe structural condition according to the requirements of the International Building Code.
•Section 307.2 Cutting, notching or bored holes. *
•Installations and alterations resulting in additional structural loads to any member (HVAC equipment etc.) shall not be permitted without verification that the truss is capable of supporting the additional load.
•A good example would be the addition of an air handler in the attic which is supported from the truss.
•Section 307.3 Penetrations or floor/ceiling assemblies and fire resistant-rated assemblies.
•Penetrations of floor/ceiling assemblies and assemblies required to have a fire-resistance rating shall be protected in accordance with the IBC.
•Section 307.4 Alterations to trusses.
•Truss members and components shall not be cut, drilled, notched, spliced or otherwise altered in any way without written concurrence and approval of a registered design professional. ***
•IPC Section 307.5 Trench location.
•Trenches installed parallel to footings shall not extend below the 45 degree bearing plane of the footing or wall.
•IPC Section 307.6 Piping materials exposed within plenums.
•All piping materials exposed within plenums shall comply with the provisions of the International Mechanical Code.
•IPC Section 308 Piping Support.
•Section 308.1 General.
•All plumbing piping shall be supported in accordance with this section.
Section 308.2 Piping seismic supports.
•Where earthquake loads are applicable in accordance with the building code, plumbing piping supports shall be designed and installed for the seismic forces in accordance with the International Building Code.
•Section 308.3 Materials.
•Hangers, anchors and supports shall support the piping and the contents of the piping. Hangers and strapping material shall be of approved material that will not promote galvanic action. ***
•Section 308.4 Structural attachment.
•Hangers and anchors shall be attached to the building construction in an approved manner.
•Piping cannot be supported from other piping. *
•Section 308.5 Interval of support.
•Pipe shall be supported in accordance with Table 308.5.
•Exception: The interval of support for piping systems designed to provide for expansion/contraction shall conform to the engineered design in accordance with section 316.1.
•Many pipe manufacturers have more stringent requirements which govern the installation. In some cases the manufacturers have less stringent requirements such as the maximum distance between hangers. In this case the more stringent requirement (code) would apply.
Section 308.6 Sway bracing***
Usually not addressed by the designer, performed by the installer or identified by the inspector.
•Rigid sway bracing shall be provided at changes in direction greater than 45 degrees for pipe sizes 4 inches and larger.
•This section contains lateral support requirements for pipe 4” and larger in diameter. The flow of waste in the drainage piping subjects the piping to the forces that result from the momentum of the waste.
•These products are a product of the mass and velocity of the flow together with the change in direction of the pipe and can be quite large, especially in piping 4” and larger. Without adequate bracing, the piping could be damaged or joint failure could occur.
Examples of sway bracing and anchorage
•Section 308.7 Anchorage.*** Same issues as Sway bracing!
•Anchorage shall be provided to restrain drainage piping from axial movement.
•Section 308.7.1 Location.
•For pipe sizes greater than four inches, restraints shall be provided for drain pipes at all changes in direction and at all changes in diameter greater than two pipe sizes. Braces, blocks, rodding and other suitable methods as specified by the coupling manufacturer shall be utilized.

Examples of sway bracing and anchorage

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