Letter to the Editor (April 2010)

What UV protection options are available for pipe that is already installed?

Lloyd Waite, Halverson Mechanical, OgdenUtah

Once installed, there are several ways to protect the PP-R pipe. Physically, the pipe can simply be shaded or covered with a metal casing of some sort. As long as the casing isn't clamped directly to the pipe, the pipe will be undamaged by these methods. However, this is not ideal in many cases, due to simple logistics.

The most effective solution we've found is to paint the pipe, but due to the flexible nature of PP-R and the normal expansion and contraction that can occur in a piping application, most forms of paint are unacceptable. We recommend the use of a heavy-duty, water-based, elastomeric acrylic coating, which can adjust with the pipe without cracking. This technique can also be used to cover the pipe if it needs to be recolored for aesthetic purposes.

In order for the coating to properly bond to the pipe, the exterior surface will need to be roughed up using medium-grade sandpaper and then have the dust brushed away with a dry cloth. Coating the fittings is not required, as the heavy-walled fittings are unlikely to fail. However, if the area is exposed to long daylight hours with direct sunlight, the extra precaution may be advisable. There is no negative effect to coating the fittings.

We have not included this method in our normal literature for two purposes. First, we wish to direct installers towards the Aquatherm-manufactured UV protected pipe, as this is the most reliable solution. Painting or covering the pipe is only intended as a contingency method. Secondly, we try to avoid directly endorsing products that are produced by other companies within our standard literature. This is simply for proprietary reasons, as we are unable to control or regulate the production methods or quality assurances of a third party.