IRN R070

The Water Supply (Water Fittings) Regulations 1999, the Water Supply (Water Fittings) Regulations (Northern Ireland) 2009, and the Water Supply (Water Fittings) (scotland) Byelaws 2014, preclude the connection of rim feed or ascending spray type bidets or bidets with hand - held spray attachments directly to any supply pipe.

BIDETS WITH OVER-RIM SUPPLY ARRANGEMENTS

(a)	Bidets installed in domestic locations of the over-rim type, that have no ascending spray and/or flexible hose may be supplied with cold and hot water through single or combination tap assemblies from either a supply pipe or a distributing pipe providing that a Type AUK2 air gap is provided between the outlet of the water fitting and the spillover level of the bidet and shall also comply with (c) below.
(b)	Bidets installed in premises other than domestic locations of the over-rim type, that have no ascending spray and/or flexible hose where a higher fluid category of risk may be present, may be supplied with cold and hot water through single or combination tap assemblies from either a supply pipe or a distributing pipe providing that a Type AUK3 air gap is provided between the outlet of the water fitting and the spillover level of the bidet as (a) above and shall also comply with (c) below.
(c)	In the case of a bidet equipped with a single outlet (single flow) mixing tap, shall also be installed in accordance with IRN R010. See Diagram 1 below.

BIDETS (INCLUDING WCs ADAPTED AS BIDETS) WITH SUBMERGED WATER INLETS AND/OR FLEXIBLE HOSE WITH SPRAY OR JET HANDSET FITTINGS

Bidets, including WCs adapted as bidets, incorporating an ascending spray inlet or utilising a flexible hose or an arrangement with a spray or jet, are a fluid category 5 risk in that the ascending spray inlet could be contaminated with urine or other matter and the spray or jet handset could be deposited in the bidet or WC. Bidets of this type must not be supplied with water from a cold or hot water supply pipe or a common distributing pipe. The zone of backflow risk is shown and the highest part of this zone must be not less than 15mm below any cistern serving the bidet. See Diagram 2 below.

Bidets of this type may:

a. be supplied with cold and/or hot water through Type AA, AB, AD or AUK1 backflow prevention arrangement or type DC device serving the bidet only: or Type AA, AB, AD or AUK1 air gap with or without blended water cistern or type DC backflow prevention device.

b. be supplied with cold water from an independent distributing pipe serving the bidet only, or a common distributing pipe serving the bidet and which may also serve a WC or urinal flushing cistern at a lower level; or

c. be supplied with hot water from a water heater, which is supplied from an independent distributing pipe, that serves the bidet only: or

d. where the bidet is at a lower elevation than any other outlets or appliances, be supplied with water from a common cold and/or hot water vented distribution pipe providing that;

(i) the elevation of the spillover level of the bidet, if there is no flexible hose; or

(ii) the elevation of the spray outlet, with the hose extended vertically above the spillover level of the bidet,

whichever is the highest, is not less than 300mm below the point of connection with the distributing pipe which serves other appliances or outlets.

The method of supplying water to an ascending spray and/or hose and spray bidet and which is described in the formal guidance, is difficult to achieve in practice. The air gap should be located above the fully extended hose and spray, or zone of backflow risk, and this height may need to be increased to provide sufficient water pressure, to overcome friction loss in the pipes and fittings, in order to operate the ascending spray and hose spray effectively. This method of supplying blended water to a bidet involves complicated control methods as the control of water to the bidet itself has to be linked with the control of water flow, and temperature, upstream of the air gap, blended water cistern or DC device.