Plumbing Africa May 2019 | Page 63

TECHNICAL • • • • • • • • • 15.0mm × 1.0mm 22.0mm × 1.2mm 28.0mm × 1.2mm 35.0mm × 1.5mm 42.0mm × 1.5mm 54.0mm × 1.5mm 76.1mm × 2.0mm 88.9mm × 2.0mm 108.0mm × 2.0mm. WASTEWATER JUNCTIONS ALSO CRIMP-FITTABLE A range of wastewater junctions in stainless steel has also been developed using the crimp press-fitting system. They are easy for rodding programmes to clear blockages that have developed because of the bend’s long radii and easy lateral joints. These fittings have been developed, as it was anticipated by clients and engineers that heavy expenses could be incurred when plastic or HDPE piping was used in the under-hang pipe system, and it collapses, is damaged, or leaks as a result of the rodding process. Wastewater flows by gravitation, and the main concerns are typically the build-up of fluids in the piping as a result of blockages, and/or pipe assembly configurations. Because of the uniform internal diameter of the stainless-steel piping, it would be difficult for a blockage to occur, subject only to a possible build-up of grease or fats at a relatively long www.plumbingafrica.co.za 61 distance from source on an extremely cold day, for example. This can however easily be cleared by rodding or heating to release a blockage, which is not possible with other pipe systems. Back pressure in the piping will then aid in clearing the blockage onward. WHEN STAINLESS STEEL IS THE CORRECT CHOICE Stainless steel naturally has an aesthetic appeal and can be used in any water reticulation system. It does not rust, and paint or coatings are also not necessary. However, some applications are more appropriate for this material choice. These include and are subject to the selection of the correct grade of stainless steel: • In a corrosive environment, such as where an installation would be subject to sea air or would require conveyance of chemicals, whether acidic or alkaline. • Environments with extremely low or high temperatures, to prevent challenges with brittleness or resistance, which include plastics and copper pipes. • Where high strength over mass is required. The mechanical properties of stainless steel allow thinner wall sections to be used than with other materials, thus reducing weight without compromising on strength. • Where hygienic conditions are a priority. Stainless steel is internationally recognised as the most hygienic material for processes that involve the preparation of food or beverages as well as in medical facilities due to its passive surface. Stainless steel typically has no pores or cracks to harbour dirt, grime, or bacteria. PA May 2019 Volume 25 I Number 3