We produce white polypropylene pipe for hot and cold water systems. The most common question we receive from contractors is not about pressure ratings, or material grade. It's about joint failure. Specifically, why do some fusion joints leak and others last for decades? We've looked at installation data from several job sites. Most failures are caused by three errors in the heat fusion process. Here's what to do to avoid them.
Temperature and Heating Time
White polypropylene pipe melts at 260°C. Heating time depends on pipe diameter. A 20mm pipe takes about 5 seconds on the heating tool. A 50mm pipe takes about 10 sec. A 110mm pipe takes up to 18 seconds. One common mistake is using the same timing for all sizes. Heating does not complete the molecular bond. Over-heating harms the polymer and creates brittle spots at the joint. We give all the welding tools with a timing chart printed on it. Contractors using it report leak rates below 2% on hydrostatic testing.
Technique of Insertion
After heating the pipe and fitting must be pushed together straight. As the pipe is inserted, twisting or rotating it creates microscopic shear lines in the molten plastic. These lines become the starting points of cracks when under stress. We have cut out failed joints and seen visible twist marks in the fusion zone. The proper way is to line the pipe and fitting up before heating and then push straight without turning. Keep the joint still until it is completely cool. A 20 mm joint is about 30 sec. 50mm joint 2 minutes. If the pipe is moved before it has cooled residual stresses are built up, which cause slow crack growth.
Light Blocking & Inspection
Our white polypropylene pipe has a special additive which blocks light and prevents algae growth inside the pipe. This is especially important for systems where water sits stagnant for periods of time, such as commercial buildings or seasonal shutdowns. Algae growth can impact water quality and lead to complaints. The all-white surface is also helpful during inspection. Any contamination or debris inside the pipe is visible prior to closing the joint. The white bore made it easier to see foreign material and one contractor said he had a higher pass rate on his inspection.
We provide white polypropylene pipe in sizes of 20mm, 25mm, 32mm and other mainstream sizes. It is suitable for use with hot and cold water pipe applications. Before delivery, each batch is checked for pressure, hygiene and aging. Request a sample length and test the fusion process on your existing pipe.
