PVC pipes for pressurised sewer and/or water systems are KIWA certified and are available in two colours: - medium grey (RAL 7037 KOMO) for sewage pipes. - dark grey (RAL 7011 KOMO) for pressurised sewer systems and above-ground water mains. PVC pipes for drinking water (below ground) are KIWA certified and are available in one colour: cream (RAL 1015). Where applicable, the fittings are also KIWA certified. This section includes push-fit and solvent and fittings. For tension-resistant connections use solvent weld fittings.