CRIMP FITTING

Case Description

During a major home remodel project, new plumbing was installed in a master and guest bathroom. The plumbing utilized a variety of adapter fittings to connect the copper piping to PEX lines, attached using crimp ring fittings. Allegedly, a crimp ring failed, leading to severe water loss. A fitting that cost less than $0.50, led to thousands in damages and repairs.

Steps Taken:

ARCCA’s expert conducted a thorough investigation of the evidence to determine the root cause of the failure:

  • Review of the initial documentation including work requested, work performed and all relevant purchase orders.
  • Analysis of the timeline of events to determine likely failure modes.
  • Incident location inspection observing orientation and application of pluming lines and fixtures.
  • Stereo Optical Microscopy (SOM) to identify key areas requiring additional exploration.
  • Examination of higher magnification Scanning Electron Microscope (SEM) images to observe surface topography.
  • Energy Dispersive X-ray Spectroscopy (EDX) for elemental analysis to determine component composition.
  • Review of the incident component’s product manuals and installation equipment and requirements.

Final Findings:

  • ARCCA’s investigation revealed the water loss was a result of a failed stainless-steel crimp fitting connecting copper piping to PEX lines. Based on the timeline of events, the failure occurred approximately 8 years following the initial installation. The timeline of events is important as significant time had passed between installation and failure, however provided documentation from the crimp manufacturer indicates that 8 years is well below the product’s expected life.
  • The incident clamp exhibited a similar chemical composition to an exemplar clamp ruling out material degradation from oxidation that would weaken the crimp. This evidence also supports the notion that the failure was not solely a product of environmental causes such as corrosion.
  • The incident fitting was found to exhibit significant crack propagation from the leading edge of the internal radii of the crimped connection. The presence of these cracks indicates incorrect installation from excessive crimping. The manufacturer provides detailed specifications as to the required installation procedure.
  • ARCCA concluded that the original installation was performed incorrectly and that over time the cracks propagated through the entire thickness of the fitting until catastrophic failure.

Crimp Fitting Failure Analysis Case Study - Crimp Fitting 2
Crimp Fitting Failure Analysis Case Study - Crimp Fitting Graph

Crimp Fitting Failure Analysis Case Study - Crimp Fitting img91
Crimp Fitting Failure Analysis Case Study - Crimp Fitting img97