2024 INTERNATIONAL PLUMBING CODE
THE FOLLOWING IS NEW LANGUAGE THAT WILL BE IN THE 2024 INTERNATIONAL PLUMBING CODE WHEN IT IS PRINTED. This code change was proposed by the Structural Engineers Association of Texas (SEAoT) and was supported by testimony at the ICC Code Action Hearings from the Geoprofessional Business Association (GBA), American Institute of Architects (AIA), the American Council of Engineering Companies in Texas (ACEC Texas) , as well as various design professionals that have had Owners make claims that their firms were negligent in not sufficiently isolating under-slab plumbing under isolated slabs. This language explicitly requires isolation of plumbing under isolated slabs and it will be in addition to language that is already in the existing IPC which requires plumbing be protected from expansive soil damage.
305.8 Expansive Soil. Where expansive soil is identified under buildings in accordance with Section 1803.5.3 of the International Building Code, but not removed in accordance with Section 1808.6.3 of the International Building Code, plumbing shall be protected in accordance with Section 305.8.1 or 305.8.2.
305.8.1 Non-Isolated Foundations. Under foundations with slabs that are structurally supported by a subgrade, it shall be permitted for plumbing to be buried.
305.8.2 Isolated Foundations. Under foundations with a slab or framing that structurally spans over an under-floor space which isolates the slab or framing from the effects of expansive soil swelling and shrinking in accordance with Section 1808.6.1 of the International Building Code, the plumbing shall be suspended so that plumbing, hangers and supports are isolated, by a voidspace, from the effects of expansive soil swelling and shrinking.
Exception: It shall be permitted for plumbing to be buried if the plumbing provides drainage of an under-floor space.
To protect the voidspace, soil shall be sloped, benched or retained in accordance with an approved design methodology.
It shall not be permitted for the plumbing, hangers and supports below the slab or below the framing to be in contact with soil or any assemblage of materials that is in contact with soil within the active zone. It shall not be permitted for a slab and plumbing to be lifted as an assembly to create the voidspace unless the under-floor space is a crawlspace with access to allow inspection of plumbing after lifting.
Exception: It shall be permitted for the piping, fittings, hangers, and supports below the slab or below the framing to be in contact with structural elements of the foundation that are designed to resist the effects of expansive soil swelling and shrinking in accordance with Section 1808.6.1 of the International Building Code.
Organic materials subject to decay shall not be used for hangers, supports and soil retention systems. Materials subject to corrosion shall not be used for hangers, supports and soil retention systems unless protected in an approved manner.
Where plumbing transitions to a buried condition beyond the perimeter of the foundation, an adequately flexible expansion joint shall be provided in the plumbing system to accommodate the effects of expansive soil swelling and shrinking.