Solution

Pipe Failures in Residential Plumbing and Heating Systems

United States and Canada

Service: Materials Investigation, Structural Investigation

Market: Water/Wastewater

Keywords: Laboratory Testing and Analysis, Materials Analysis, Pipe, Plastic/Composite, Residential

Client

Merrill, Nomura & Molineux, LLP

Completion

2010

Pipe Failures in Residential Plumbing and Heating Systems

SGH investigated the cause of failures in pipes used in residential domestic hot water and hydronic heating systems in the United States and Canada. Occurring after less than 10 yrs in service, the failures of crosslinked polyethylene-aluminum-crosslinked polyethylene (PEX-Al-PEX) pipe were characterized by blistering and splitting of the exterior pipe wall preceded by darkening and bulging of the outer PEX layer.

Scope | Solutions

SGH obtained field samples for laboratory examination and testing. Highlights include the following:

Observed brittle microcracking of the inner PEX layer and corrosion holes in the aluminum layer precipitating hydrostatic rupture of the outer PEX layer
Conducted testing focused on basic dimensional and material properties to determine if fundamental material or manufacturing defects were present
Determined that PEX material had low gel content (indicative of inadequate crosslinking), reducing the strength and crack resistance of the pipe
Identified early depletion of the antioxidant, decreasing the resistance to oxidative degradation and increasing susceptibility to early failure by wall rupture

Our findings contributed to settlement of a class action lawsuit on behalf of homeowners.

Project Contact(s)

Simpson Gumpertz & Heger

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Pipe Failures in Residential Plumbing and Heating Systems

Client

Completion

Scope | Solutions

Project Contact(s)

Phillip Sharff