The failure of polymer plumbing components—such as PVC, CPVC, or PEX piping systems, water filters, valves, and flexible hoses with polymer nuts—can result in significant water damage when a break occurs. In general, polymers are used as resins in plastic formulations for the manufacture of plumbing components due to their ease of production and relatively low weight, which translates into significant cost savings for the manufacturer. In addition, these polymer parts exhibit better corrosion resistance compared to metal parts. Despite their good durability, polymer parts are prone to several failure modes specific to their physicochemical and mechanical properties. Several factors can contribute to the failure of polymer parts. Here are some examples of causes of failure:

• An inappropriate choice of material for a specific application can lead to premature aging of the plumbing part;
  Manufacturing defects and imperfections that occur during the production of the polymer part are potential sources of failure;
• A flawed part design can also contribute to breakage, affecting its durability and mechanical strength (e.g., the part’s shape and the plastic’s formulation);
• Improper installation of plastic parts, such as over-tightening, can contribute to the fracture of the plumbing component;
• Improper handling by the user can accelerate the failure process of plastic parts;
• Exposure to aggressive chemicals, contaminants, or UV rays can degrade the polymer over time, leading to structural fractures in the polymeric material.

That said, environmental stress cracking in the context of plastics refers to a degradation phenomenon in which cracks form in the material due to a combination of mechanical stresses, aggressive or incompatible environmental factors, and a material susceptible to this mode of failure. The relatively high frequency of this type of failure is primarily due to a lack of understanding of chemical incompatibilities between plastic materials and chemicals, particularly widely used organic-based chemicals (e.g., oil, solvents, paint, adhesives, and detergents). Chemical incompatibilities can reduce mechanical properties, including creep resistance and fatigue resistance. Degradation of the polymer by aggressive chemicals can lead to undesirable chemical reactions, which can also contribute to the weakening of the material. To avoid these problems, it is essential to select polymers that are chemically compatible with their intended application, taking potential contaminants into account. Thorough studies of chemical compatibility during the design phase of facilities are often necessary to ensure the durability of polymeric materials in various applications.

It should also be noted that the type of polymer used in the plastic formulation plays a key role, as each polymer reacts differently to environmental stresses. Furthermore, the effectiveness of stabilizing additives and antioxidants used in the plastic formulation also impacts durability and resistance to cracking under environmental stresses. Higher temperatures also promote this type of failure by facilitating cracking. Mechanical stresses, such as tension, compression, bending, and clamping force, can accelerate degradation and cracking. It is also important to note that the geometry of the plastic part chosen during the manufacturer’s design process influences its susceptibility to cracking. Plastics are susceptible to notch effects when plumbing components are not rounded, as this leads to local stress concentrations at the edges. Assessing these various factors is essential for a root-cause investigation involving the use of polymeric materials in plumbing.

Forensic investigation of polymer failures remains complex. For this reason, a thorough analysis is essential to identify the polymer from which the plumbing component is made, to detect the presence of any contaminants incompatible with that polymer, and to evaluate all contributing factors in order to establish the probable cause.

Origin, backed by its team of materials experts, has participated in numerous cases involving this type of water damage resulting from the failure of polymer plumbing components. We invite you to contact us today at info@origin.expert for any new assignment or to request that a materials, metallurgy, and chemistry expert contact you regarding an insurance claim. We are ready to provide our expertise for your cases. We are also eager to collaborate with you to offer the most appropriate recourse solutions for your cases, thereby ensuring the strength of your position in the event of a dispute.