No matter where you’re standing, it’s likely that you’re surrounded by kilometres upon kilometres of pipes. Electrical cabling runs underground through piping, sewerage runs through piping, potable plumbing water runs through piping and piping is also key to irrigation systems.
Here we consider the different types of materials used for piping, along with their pros and cons.
The problem with using galvanised steel for plumbing is that it invariably corrodes over time, adding unwanted chemicals to water and ultimately restricting flow. The galvanisation simply can’t stave off rust forever.
Designers working with galvanised steel piping estimate that within 15 years of operation, the capacity for flow in steel piping can be reduced by up to 50%. This is due to flakes of corrosion and the steel itself clogging up irrigation nozzles.
Found mostly in city water mains, cast-iron piping suffers from the same problems as steel piping – corrosion and flow impairment. It’s somewhat more resilient than galvanised steel, although also more expensive. Designers estimate that cast-iron takes 18 years (or 3 years longer than steel) to rust and clog to the degree where flow is hampered by 50%.
Lightweight and strong, asbestos-cement piping makes it unnecessary to worry about rust and corrosion. It also doesn’t conduct electricity. However, it’s comparatively brittle. This means that asbestos-cement piping that’s laid too deep can be put under too much pressure, causing pipe damage. The piping must also be carefully installed so it doesn’t come into contact with any tree roots, rocks or other debris.
None of the problems that affect other piping materials apply to thermoplastic piping. It doesn’t rust or corrode, it’s not brittle, it’s light but strong, it’s generally far cheaper than metallic piping and it doesn’t have to be protected from contact with debris.
Developed during the Second World War and commercially available from the 1940s on, plastic irrigation piping really hit the market hard in the 1960s. Today it’s by far the most common form of irrigation piping used today. It’s estimated that over 100,000 miles of it are installed throughout North America each year.
There are three available varieties of thermoplastic piping – SDR-PR, PE and PVC. Of these, PVC (polyvinyl chloride) is by far the most popular. It’s also the most durable because it’s resistant to damage from the chlorine in water, whether from a pool system or in potable drinking water.
Thermoplastic piping, along with advances in the science of hydraulic water transportation, has revolutionised the irrigation industry, resulting in irrigation systems that work better and last significantly longer than in the past.