Use of Exemplar Testing to Investigate Claims of Overtightening of Brass Plumbing Fittings

Many expert witnesses have encountered plumbing fittings made from high-zinc brass alloys that have failed by stress-corrosion cracking (SCC) in potable water service. Oftentimes, the resulting subrogation claims involve (at least) the property owner, the product manufacturer, and the installer of the fitting. Clear instructions on the necessary tightness for the connection are rarely available. Thus, reliable assessment of whether or not the fitting had been overtightened as originally installed are often difficult or unreliable. Exemplar testing can be a useful tool to assess whether claims of overtightening can be reliably supported.