Water Regs Schedule 1

• defines categories of fluids
• Blue Water – corrosion of copper caused by stagnation
• Air Gap = which is greater: 20mm or 2 x inlet Ø (MIN 25 mm for the bath)

Category 1

• wholesome water to Schedule 67 of the Water Industry Act 1991
• water supplied from the Water Undertakers

Category 3

• low toxicity;
• slight health hazard (showers, bathes, washbasins; hose with shut-off control, domestic heating system; WC cistern)
• Prevention: EC/ED - Double Check Valve (Verifiable/None-verifiable; reed more); HUK1; CA;
• Air Gaps: AG; AUK1(back-siphonage 5); AUK2;

Category 4

• toxic substances;
• significant health hazard (non domestic heating, anti-freeze, mini-irrigation systems, permeable hoses, fire sprinkler with additives)
• Prevention: BA - Reduced Pressure Zone Valve (RPZ; reed more)

Category 5

• Serious health hazard (WC pan, bidet bowl, human and animal waste, laboratories, medical)
• Prevention: Air Gap Only!
• Air Gaps: AA; AB; AUK3; DC;