3IEC60335-1:2001+A1:2004+A2:2006 Household and similar electrical appliances -Safety -Part 1:General requirements
4IEC 61770:2006 Electric appliances connected to the water mains - Avoidance of backsiphonage and failure of hose-sets.
5IEC60335-2-79:2002+A1:2004+A2:2007 Household and similar electrical appliances - Safety - Part 2-79: Particular requirements for high pressure cleaners and steam cleaners
6Public Health Risk Management Plan Guide'Distribution System - Backflow Prevention',version 1, Ref D2.4 published by Ministry of Health.