WATER FITTINGS AND MATERIALS DIRECTORY
AMENDMENT No. 29 MAY 2013
As the incorrect installation of water fittings may result in
contravention of Water Byelaws or Regulations the following INSTALLATION
REQUIREMENTS & NOTES (IRNs) are intended as guides to Water Suppliers,
Installers and their customers. The IRN numbers appear at the top of
each entry in the Fittings section of the Directory
Installation Requirements and Notes under the Water Supply
(Water Fittings) Regulations 1999 in England and Wales, the Water
Byelaws 2004 in Scotland and the Water Supply (Water Fittings)
Regulations (Northern Ireland) 2009.
IRNs listed in this section all begin with the letter R to denote
Installation Requirements or Notes.
text of entry for Installation Requirements or Notes.
tap or combination tap assembly has a Type AUK2 air gap and is therefore
only suitable for installation in domestic premises or in other premises
to protect against a backflow risk up to a Fluid Category 3, unless
additional backflow protection for the higher risk is included in the
tap or combination tap is installed so that its base is no lower than
the spillover level of the receiving vessel (for example, a sink or
washbasin), a Type AUK3 air gap is achieved which permits
installation of the tap in any premises where backflow protection up to
Fluid Category 5 is required at the tap.
supply hoses to be installed where light is excluded
supplies shall be at reasonably balanced pressures from a common source
(e.g. hot and cold supplies both from the same storage or both from a
supply pipe). Where the fitting is supplied from unbalanced supplies
(e.g. hot and cold supplies from separate sources) an ‘Approved’
single check valve or some other no less effective backflow
prevention device shall be fitted immediately upstream of both hot and
cold water inlets.
Multiple inlet fittings installed in domestic premises and supplied from
unbalanced supplies (e/g hot and cold supplies from separate sources)
shall be installed in accordance with IRN R010 and with a double check
valve or some other no less effective backflow prevention device fitted
at the connection to the shower hose pipe. A single check valve or
vacuum breaker may be fitted in place of the double check valve if
single check valves are fitted at each inlet to the fitting.
Alternatively the fitting shall be supplied in accordance with IRN R040
unless the shower head is constrained above the spill-over level of the
bath, wash basin or shower tray.
Multiple inlet fittings installed in domestic premises or in other
premises to protest against a backflow risk up to a Fluid Category 3,
incorporating a self cancelling diverter acceptable as a backflow
prevention device (HC) and having an AUK2 or AUK3 air gap, shall be
installed in accordance with IRN R010.
Multiple inlet fittings installed in premises other than domestic to
protect against a backflow risk up to a Fluid Category 5, incorporating
a self cancelling diverter acceptable as a backflow prevention device
(HC only) and having an AUK3 air gap, shall be installed in accordance
with IRN R010 and the shower hose shall be constrained as indicated in
Schedule 2-15 (1)
fitting, or outlet supplied by the fitting, shall be installed so that its outlet discharges above the
spill-over level of any fixed appliance as indicated below: -
For backflow protection in domestic premises or
installations up to, and including, Fluid Category 3.
Size of tap or combination fitting.
Vertical distance of outlet above spill-over level.
not exceeding ½in
exceeding ½in but not exceeding ¾in
fitting cannot be installed as indicated in the table it shall be
a) with an
approved double check valve assembly or some other no less effective
backflow prevention device immediately upstream of the inlet; or
so that it
draws water by gravity only from a cistern, or cylinder having a
permanently open vent pipe, and the distributing pipe supplies no other
fittings (other than a draining tap) at a lower level.
backflow protection in premises or installations up to, and including
Fluid Category 5.
vertical distance of the outlet above the spill-over level shall be not
less than 20 mm or twice the diameter of the inlet pipe to the fitting,
whichever is the greater.
fitting cannot be installed as indicated it shall be installed with a
backflow prevention arrangement suitable for the Fluid Category.
Taps incorporating a hose union outlet
If the outlet of the tap assembly is designed to accommodate the
attachment of a flexible hose and therefore potentially
compromise the required AUK3 air gap, alternative Fluid Category
5 backflow protection is required, as the AUK3 air gap provided
by the tap would not apply.
and combination fittings discharging in a non-domestic location and any
appliances in premises where a higher level of protection is required,
such as appliances in hospitals or other health care premises require a
Type AUK3 tap gap.
in existing house installations a hose pipe is to be used from an
existing hose union tap located outside a house and which is not
provided with backflow protection, either:
the existing hose union tap should be provided with a double
check valve (Type EC or ED) located inside the building; or
the tap should be replaced with a hose union tap that incorporates a double check valve (type (HUK1); or
union backflow prevention (Type HA) or a double check valve
(Type EC or ED) should be continuously fitted to the outlet of
the tap; or
legally installed in any premises.
Water Supply (Water Fittings) Regulations 1999 and the Water Byelaws
2000, Scotland preclude the connection of rim feed or ascending spray
type bidets or bidets with hand - held spray attachments directly to any
BIDETS WITH OVER-RIM SUPPLY ARRANGEMENTS
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.
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)
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.
of this type may:
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. See Diagram 3: or Type AA, AB, AD or
AUK1 air gap with or without blended water cistern or type DC
backflow prevention device.
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. See Diagram 4; or
be supplied with hot water from a water heater, which is
supplied from an independent distributing pipe, that serves the
bidet only. See Diagram 4: or
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;
the elevation of the spillover level of the bidet, if there
is no flexible hose; or
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. See Diagram 5.
method of supplying water to an ascending spray and/or hose and spray
bidet as illustrated in Diagram 3 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.
(4) The requirement in sub-paragraph (1)(i) of Schedule 2.25(4)
shall be deemed to be satisfied if, (a) in the case of an
automatically operated flushing cistern servicing urinals which
is filled with water at a rate not exceeding –
(i) 10 litres per hour for a cistern serving a single urinal;
(ii) 7.5 litres per hour per urinal bowl or stall, or, as the
case may be, for each 700mm width of urinal slab, for a cistern
serving two or more urinals;
(b) in the case of a manually or automatically operated pressure
flushing valve used for flushing urinals which delivers not more
than 1.5 litres per bowl or position each time the device is
Fittings incorporating fluid category 3 backflow protection shall
be supplied by gravity from a cistern having family ‘A’
backflow protection by means of a distributing pipe which does not
supply any other fittings at a lower level.
Supply(ies) shall be via fluid category 5 backflow protection or by
gravity from a cistern incorporating family ‘A’ backflow protection by
distributing pipe(s) to which no fittings for other purposes are
Supply(ies) shall be from storage.
above ground use, cold water services only, unless indicated otherwise
in the description of entry.~
fitting is to be so installed as to be readily accessible for
examination, test, maintenance, replacement or operation.
outlet connections to cisterns, which are arranged to receive thermal
expansion water, shall be fitted both internally and externally with
suitably protected support washers.
IRN R140 ~
primary circuits and /or secondary hot water systems shall incorporate a
means for accommodating the thermal expansion of water to prevent any
discharge from the circuit and/or system except in an emergency
‘Approved’ single check valve or some other no less effective backflow
prevention device providing backflow prevention protection to at least
fluid category two shall be fitted at the point of connection(s) between
the water supply and the fitting or appliance.
‘Approved’ single check valve must be fitted as close as possible to the
T-off supplying the device.
`Approved` double check valve or some other no less effective device
providing backflow prevention protection to at least fluid category
three shall be fitted at the point of connection(s) between the water
supply and the fitting or appliance.
Where the DC pipe interrupter is used, it must be installed so
that the lowest point of the air aperture is not less than 150mm
above the spillover level of the receiving receptacle, and have
no valve, flow restrictor or tap on its outlet.
Water Undertakers cannot be responsible for the quality of water
passed from these fittings.
Schedule 2-15 (1)
Water Undertakers cannot be responsible for the quality of ice
passed from these fittings.
supply to the storage cistern shall be discharged via a Type AA air gap.
closed circuit use only.
supply to this fitting/appliance shall be by means of a metered supply
alloys containing lead shall not be used in connection with systems
which convey or receive water supplied for domestic purposes.
installed for domestic purposes in commercial premises, or elsewhere
with the written consent of the undertakers, the fitting shall be
installed with a backflow prevention device adequate for the class of
cistern is not suitable for storing water for domestic purposes.
vent, warning or overflow pipe from a primary feed cistern shall convey
water to any cistern supplying water to a secondary system from which
water may be drawn for domestic purposes.
fitting is not suitable for conveying hot water.
storage cistern, except one supplying water to the primary circuit of a
heating system, shall be fitted with a servicing valve on the outlet
servicing valve shall be installed on the supply to the fitting in a
readily accessible location.
IRN R290 Schedule 2:
26 & 27
It is recommended that a drinking water tap shall be provided upstream
of this fitting.
some water supply areas it is advisable that copper cylinders and tanks
be fitted with aluminium protector rods to promote resistance to
corrosion. For further guidance consult your local water undertaker.
some water supply areas require aluminium covers to be protected by a
‘Approved’ paint or lacquer. For further guidance consult your local
In some areas of water supply only galvanised Grade A mild steel
cisterns will be accepted. For further guidance consult your local water
In some water supply areas galvanising is required to be coated
with a ‘Approved’ protective paint. For further guidance consult your
local water undertaker
In some water supply areas galvanising is not accepted as a
suitable means of internal protection for fittings. For further guidance
consult your local water undertaker
Float-controlled valves or equivalent inlet devices should be securely
and rigidly attached to the cistern and installed so that the valve
closes when the level of the water is not less than 25 mm below the
overflowing level of the cistern. Where the cistern is fitted with an
approved alternative to a warning pipe, such as an indicator instrument
or visual or audible alarm, the inlet valve is to close when the water
level is not less that 50 mm below the overflowing level of the cistern.
Domestic unvented primary circuits may be filled or replenished by
means of a temporary connection between the primary circuit and the
supply pipe. An ‘Approved’ double check valve shall be installed at the
point of connection to the supply pipe. A permanent connection between
the primary circuit and the supply pipe may be made via a CA backflow
prevention device or some other no less effective backflow prevention
All fittings manufactured from duplex (alpha-beta) brass are
unacceptable for underground use, for backflow prevention devices and
for certain products specified by the water undertaker.
Transient pressures may be evident from noise generated within the
system as ‘water hammer’ - emanating from pipes as a result of rapid closure of a draw off tap or from rapid oscillation
of a float operated valve.
inlet strainer or line strainer shall be provided at the inlet.
a pressure flushing valve is connected to a supply pipe or distributing
pipe, the flushing arrangement shall incorporate a backflow prevention
device consisting of a permanently vented pipe interrupter located not
less than 300mm above the spillover level of the WC pan.
Every water closet pan shall be supplied with water from a
flushing cistern, pressure flushing cistern or pressure flushing
valve, and shall be so made and installed that after normal use
its contents can be cleared effectively by a single flush of
water, or where the installation is designed to receive flushes
of different volumes, by the largest of those flushes.
No pressure flushing valve shall be installed -
in a house, or
in any building not being a house where a minimum flow rate
of 1.2 litres per second cannot be achieved at the appliance.
No flushing device installed for use with a WC pan shall give a
single flush exceeding 6 litres.
Written approval should be obtained from the water supplier before the
installation of this fitting or appliance.
Having obtained consent from the water supplier for the
installation of a BA device (RPZ valve) as required by
Regulation 5 of the Water Supply (Water Fittings) Regulations
1999; the installation of the BA device (RPZ valve) and any
associated fittings must be installed in accordance with the
water suppliers “Approved
Installation Method” AIM-08-01. A copy of
the AIM can be found on the WRAS website at the following link
water fittings located outside the thermal envelope, or those outside
the building should be located and installed in such a manner that will
ensure protection from freezing, undue warming or damage by other means.
When this appliance
is fitted externally, the outlet of the tap should be protected
against damage and contamination from environmental factors
Supply(ies) shall be from storage, unless with the undertaker’s consent.
This machine has not been
tested to the consumption requirements of the regulations and therefore
it may not be suitable for installation for domestic use.
has no in built backflow protection and should therefore be
installed in accordance with IGN 9-04-01 following an assessment of
the risk involved.
has in built backflow protection to fluid category 3 but where
installation may have a higher degree of risk an assessment may be
undertaken and IGN 9-04-01 applied.
has in built backflow protection to fluid category 4 but where
installation may have a higher degree of risk an assessment may be
undertaken and IGN 9-04-01 applied.
Because this WC
cistern incorporates an internal warning pipe discharging into the WC
pan and a float operated inlet valve of a compact type, an inlet or
in-line strainer must be fitted up-stream of the valve.
Cold water feed tank
not be used to supply other fittings
This unit must discharge via
a backflow protection device which gives fluid category 5 protection,
for example a type AA or AB air gap or an air break to drain that
complies with BS EN 1717
flexible hose assembly installed upstream of a terminal fitting, (tap,
valve, pipework etc.) is intended to accommodate repeated movement of
the terminal fitting, it shall be installed so as to minimise any stress
that may cause premature wear or failure of the hose due to either the
initial installation or any foreseeable movement of the hose and fitting
that the backflow prevention device in this appliance can operate
correctly by allowing water to discharge freely from the
weir, overflow or spillover positioned flush with the casing of the
appliance, a permanent spacer must be provided to ensure the appliance
cannot be installed tightly against any surface (e.g. wall or other
appliance) in a way which interferes with the free discharge of water.
‘Approved’ device providing backflow prevention protection to at least
fluid category four shall be fitted at every point of connection between
the water supply and the fitting or appliance.
Expansion vessels should be installed in the vertical orientation and located so that
the length of the connecting pipework is kept to a minimum
The length of connecting pipework to this fitting should be kept
to a minimum in order to prevent stagnation.