You can scroll through the slides of the 2024 ASPE-approved 1.0 Continuing Education Unit course below, which explains why "non-isolated void systems" are non-isolated plumbing systems. "Non-isolated void systems" have a "void" space but do not isolate plumbing, hangers and supports below the slab as explicitly required by the 2024 IPC, even though the product manufacturers often claim that their product "isolates" the plumbing. Engineers that specify non-isolated plumbing under isolated slabs have been found negligent in court. 10 different independent Professional Engineers (Mechanical, Structural and Geotechnical) from 10 different engineering firms have presented similar information to half a dozen audiences nationally. Additional presentations are provided below the ASPE (American Society of Plumbing Engineers) course.​
At the American Society of Plumbing Engineers (ASPE) national Technical Symposium in 2023, 3 engineers (1 geotechnical, 1 mechanical and 1 structural) from 3 different engineering firms presented pictures of non-isolated plumbing failures, such as failures of non-isolated void systems. All 3 of the ASPE TechSymposium presenters also stated, "All 3 presenters of this 2023 ASPE Tech Symposium presentation today agree with the content and recommendations presented at the North Texas BPI Presentation by those 3 engineers." Below is the ASPE Tech Symposium slide deck followed by the BPI slide deck.​
In 2022, independent engineers reviewed the state of the practice at that time, related to the protection of plumbing from expansive soils under foundations, in a 3 hour presentation to the Building Professional Institute (www.bpi-tx.com). Below are the slides from the presentation that was given by 3 engineers (1 geotechnical, 1 mechanical and 1 structural) with each one having over 40 years of experience with expansive soils in their respective disciplines. In their presentation, they refer to major litigation arising from failures of non-isolated plumbing under isolated slabs and the recommend Mechanical Engineers “immediately cease and desist the practice of permitting Non-Isolated Plumbing (Buried Plumbing or Non-Isolated Void Systems) under Slab-On-Voidwork foundations…”. ​​​​​
In 2022, a second review of the above Building Professional Institute presentation was presented by another set of 3 engineers (another 1 geotechnical, 1 mechanical and 1 structural) from 3 different engineering firms to the Dallas Chapter of the Structural Engineers Association of Texas. All 3 of the SEAoT Dallas presenters also stated, "All 3 presenters of this SEAoT Dallas presentation today agree with the content and recommendations presented at the North Texas BPI Presentation by those 3 engineers." Below is the SEAoT Dallas presentation.
WHY SPECIFY MUDSKIPPER?
All plumbing codes ever published require protection of plumbing from expansive soil under foundations.
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Under isolated slabs, plumbing is effectively protected only if the plumbing, hangers and supports below the slab are all isolated.
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The Mudskipper System is the most cost effective way to isolate plumbing under slabs-on-voidwork.
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While post-installation methods can isolate plumbing, only Mudskipper isolates pre-installed plumbing under slabs-on-voidwork.