The weakest point may be exceptionally weak (where it should have been able to withstand the pressure) or it may be commonly weak (due to joints or connections which are naturally weaker than the pipes themselves). Here we delve into 3 common factors that contribute to weak pipes.
Corrosion is perhaps the most common cause of weakness, specifically in copper piping. According to the Foundation of Water Research, copper inherently has protective films which get broken down by water that has a high pH (often referred to as ‘hard water’), but this is not the only cause of corrosion. A few other factors that lead to corrosion include:
- Biofilms, a film housing bacteria inside the pipe
- Flux residues left in the pipe after installation or as a result of manufacturers defect
- High velocity or changing direction of water movement
- Construction defect, pairing incompatible metals
When the pipe is corroding it is called ‘cuprosolvency’, which means the dissolution of the copper surface. Cuprosolvency becomes visible on the exterior of the pipe when white or blue growth develops, indicating weakened areas of the pipe (pinholes) or around the joints. If the corrosion occurs in the pipe itself, a pinhole may develop, which is visible from the outside of the pipe.
If the area of piping is unavailable for visual inspection, looking below and around the pipe will often reveal evidence that a pinhole leak existed in that area. Water stains, fungus, mold and blistering, on the surfaces under the pipe indicate ongoing moisture, or a slow leak.
In newly constructed plumbing, an indication that corrosion is occurring typically manifests itself early on, as water may come out of the tap with a blue-ish hue and can taste metallic. Eventually, the white or blue build up will become evident on the exterior of the copper pipes (at the pinhole or at the joints) and even sometimes around the taps.
Improper installation can create immediate weaknesses in the piping and joints or lead to corrosion, which over time weakens the system. These can appear similar to issues resulting from a manufacturer’s defect in an area of piping.
We performed a causation investigation that involved a burst sprinkler system in an eight-story building, which was under construction. Our expert noted that only the sprinkler joints and heads on the second floor burst, while the others remained intact. One might assume colder temperatures on the second floor caused this phenomenon. However, upon investigation it was established that the faulty installation existed on the second floor, which led to expansion fractures in the improperly constructed joints, elbows and sprinkler heads. Specifically, the wrong materials were used. The pipes on the second floor were considered “exceptionally weak” and unable to withstand the pressure created from the ice damming that occurred inside the pipes.
Building Envelope and Insulation
The building envelope, insulation, piping insulation, piping materials, indoor and outdoor temperatures and duration of those temperatures are all factors leading to pipe freeze, which leads to burst.
For example, we performed an investigation of a frozen pipe in a newly constructed movie theatre. It was determined that the pipe was a sprinkler line located in the soffit near an outside wall. The break caused significant water damage. The property owner stated that the contractor had not appropriately insulated the area to prevent the pipe freeze. The contractor stated that he had adhered to the designs and contract. Our expert inspected and learned that the property owner had three other theaters with the same construction. Ultimately, the problem pointed to improper design in the buildings where piping was installed too close to the exterior walls and both pipe and walls were inadequately insulated, allowing airflow from the outside. This combined with prolonged outside temperatures below freezing caused the pipe to burst, causing water damage to the newly constructed theatre.