Recently there has been considerable confusion over the Regulations covering the supply of water to on-premise laundries (OPL). Between January 1989 and 1st July 1999 the water undertaker (supplier) had the duty to enforce the Water Byelaws for the “prevention of waste, undue consumption, mis-use, or contamination of water supplied by them”, therefore the concept is not new. The only satisfactory method of preventing back flow was covered in Byelaw 25, which required a Type ‘A’ air gap for all commercial laundry systems.
This is a method by which a supply into a cistern or a commercial washing machine is always a set distance above the highest possible level that the water could stabilise in the cistern or machine even if the overflows become clogged. (For test purposes all overflows are blanked off). The air gap between the supply and the stabilised water level, as a rule of thumb, is two times the internal diameter of the supply pipe but the level must never be less than 20mm clearance.
Reasonable time
When commercial laundry equipment suppliers developed the OPL market, many installations did not comply. Should a Water Byelaw Officer have found an installation that did not comply with Byelaw 25 usually a reasonable amount of time was allowed to put it right. If however it was connected direct on the mains this was taken very seriously indeed and urgent action would be required, particularly where foul laundry was being processed.
Failure to comply after notice had been served could be expensive as a water supply undertaker could disconnect the supply and the courts could impose a heavy fine.
On the 1st July 1999 the UK Government implemented the Water Supply (Water Fittings) Regulations which replaced the Byelaws. Europe now has in preparation a draft standard (PrEN 1717), generally in line with the UK Regulations which should harmonise the back flow requirements throughout the EEC.
The Regulations include five fluid categories of water. Categories 3, 4 and 5 cover increasing levels of risk of contamination. The Society of Laundry Engineers and Allied Trades (SLEAT) has been in correspondence with the Water Regulations Advisory Service (WRAS) and recommended the following interpretation be applied to laundries.
The above applies whether the machines are manually or coin operated. Where a risk assessment indicates a specific risk outside of the norm, the relevant risk category should be applied regardless of the above guidelines, i.e. laundry in a school that handles workwear or overalls from laboratories should be categorised as fluid 4 or 5, in line with definitions written in the Water Regulations.
For a number of years some washing machine manufacturers have incorporated a form of anti-siphon break which was usually part of the soap hopper, i.e. all the hot and cold supply water came through the soap hopper and jetted across a gap, which must be at least 20mm wide, into a secondary container. This container must have an unrestricted overflow system and if the drainage and the overflows from the machine became blocked, the water could not rise to a level that could possibly allow back siphonage. Where it can be shown that this system meets the Regulators Criteria, known as a type AD gap, it will be acceptable from 1 May 2000 for category 5 fluids.
The supplier of commercial laundry machines has two options for certification.
a. Testing to the Regulators Criteria at a United Kingdom Accreditation Service (UKAS) test house. The Water Regulations Advisory Scheme (WRAS) will accept this as complying with The Regulations.
WRAS will award a certificate of compliance under this voluntary scheme to demonstrate compliance of the equipment with The Regulations and this is 100% accepted by the UK water suppliers.
b. Manufacturers may self-certify the equipment providing that they prove the machine meets all the backflow protection requirements of the Regulations. However, be warned, the duty of each Water Undertaker’s Regulation Inspector is to ensure the quality of the evidence is satisfactory that “the machine is not installed, connected, arranged or used in such a manner that it causes, or is likely to cause waste, misuse, undue consumption or contamination of the water supplied by the Water Undertaker.” If in doubt purchasers of equipment can receive help from the WRC Valuation and Testing Centre, Fern Close, Pen-Y-Fan Industrial Estate, Oakdale, Gwent. NP1 4EH. Tel: 01495 248454 Fax: 01495 249234. You will find them extremely helpful.
Hot and cold
Commercial washers supplied into the UK usually require a hot and cold water supply, preferably softened (if not naturally soft). Hot water at 60 degrees Centigrade, cold water at ambient temperature with a supply pressure of 25 psi (1.7 bar) and must be equal pressure to hot and cold supply, producing a flow rate to each washing machine valve of at least 30 litres per minute.
When installing equipment with a certified approved air break within the machine and the cold side is connected to the water mains, the pressure from that main may be far in excess of the pressure being received from the hot water system and therefore the machine will predominantly fill with cold water and the machine will use its boost heaters to heat the water within the machine. This considerably increases cycle times, and the cost of operating these heaters can be considerable. Usually a 25lb washer has 18 kilowatts of heating and these heaters are not designed for continuous operation. Most washer manufacturers’ suppliers pass the responsibility in the small print for correct installation over to the purchaser so there is little means of redress.
Exceptions
There are two exceptions to the rules.
1. Where a commercial laundry machine is installed on the lowest point of the hot and cold supply in the building and is fed by gravity only from the domestic cistern then the machine is in compliance for category 5 fluids.
Note: Taps in the laundry room must be a minimum of 300mm above the overflow level in the machines. In this case pressure and volume may not be a problem providing the cistern is in the attic and is large enough to cope with the demand. There are of course many problems in having a laundry system in a basement but this is one of the few advantages. This system is suitable for processing laundry fluid category 5 for prevention of back siphonage but not for back pressure
(i.e washing machines must be operating on atmospheric pressure only) and hence is suitable for processing foul laundry in Red Dissolvo sacks or similar.
2. The Water Research Centre has now approved a number of Reduced Pressure Zone (RPZ) valves. They are however subject to very strict contractual installation and maintenance obligations. WRC has an information and guidance leaflet on these valves which includes a model of the necessary contracts i.e. installation can only be carried out by an accredited installer, followed by an inspection at prescribed intervals, all of which could prove very expensive. A pressure drop across the RPZ will occur, therefore you should ensure that the pressure and the flow rates will still be achieved at the washing machine inlet. These valves are suitable for the supply water to laundry fluid category 3 and 4 but not suitable for the supply to laundry fluid category 5, i.e. fouled laundry or contaminated laundry.
I believe in the future we will see more laundry machines supplied to the market, having manufacturers’ self certification as regards backflow prevention and more of these machines are ultimately going through UK accredited test laboratory services. It is certainly not true at the present time that you can only legally install a machine that has been through the test laboratories, which 1 believe is being claimed. The only thing, that is illegal is to install a water fitting in a manner that does not comply with the Regulations. ‘No water fitting shall be installed, connected, arranged or used in such a manner that it causes, or is likely to cause, waste, mis-use, undue consumption or contamination of the water supplied by the Water Undertaker.’
John Mitchell was managing director of the Zanussi Distributors in the U.K from mid 60s to 1980. A booklet ‘In-House Care Home Laundry Systems – A Practical Guide’ by John Mitchell is available at £8.75, including p&p from Mitchell Associates, Dolphins House, Mount Pleasant, West Horsley, Surrey, KT24 6BJ.
