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Installation Requirements
AMENDMENT NO.
8
OCTOBER 2002
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
PART A
Previous Installation Requirements under Water Company Byelaws prior
to enforcement of the Water Supply (Water Fittings) Regulations 1999 in
England and Wales and the Water Byelaws 2000 in Scotland. Also
applicable to Water Regulations in Northern Ireland.
IRN 000
No installation requirements or notes
IRN 001
See text of entry for installation requirements or notes
IRN 101~
Water supplies shall be at reasonably balanced pressures and taken
from a common source (both from storage by gravity or both from the
supply pipe). Where the fitting is installed in domestic premises
supplies may be taken from separate sources provided a ' Listed ' single
check valve or some other no less effective backflow prevention device
is fitted immediately upstream of both hot and cold water inlets.
IRN 103~
Multiple inlet fittings in domestic premises shall be installed in
accordance with IRN 101 and with a double check valve assembly or some
other no less effective backflow prevention device fitted at the
connection to the shower hosepipe. 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 109 unless the shower
head is constrained above the Spill-over level of the bath, wash basin
or shower tray.
IRN 104~
Multiple inlet fittings incorporating a self cancelling diverter
acceptable as a backflow prevention device shall be installed in
accordance with IRN 101 and, unless the shower head is constrained above
the spill - over level of the bath, washbasin or shower tray shall be
installed either:-
(a) with a single check valve or some other no less effective
backflow prevention device immediately upstream of each inlet; or
(b) with a single check valve or vacuum breaker fitted between the
diverter and the shower head; or
(c) so that it draws water by gravity only from a cistern, cylinder
or tank having a permanently open vent pipe, the vertical distance
between the point at which the pipe or pipes supplying water to the
fittings is or are connected to the supply and the spill-over level of
any fixed appliances is not less than 25mm, and the pipe or pipes
supply(ies) no other fitting (other than the draining tap) at a lower
level.
IRN 105~
Supply shall be by gravity from a cistern, by means of a distributing
pipe which does not supply any other fitting at a lower level.
IRN106~
Supply(ies) shall be via a type A air gap or from storage by
distributing pipe(s) to which no fittings for other purposes are
connected.
IRN 107~
Supply(ies) shall be from storage.
IRN 108~
For above ground use only on cold water services only.
IRN 109
The fitting shall be installed so that its outlet discharges above
the spill-over level of any fixed appliance as indicated in the
following table:-
If the fitting cannot be installed as indicated in the table it shall
be installed:-
a) with a 'Listed' double check valve assembly or some other no less
effective backflow prevention device immediately upstream of the inlet;
or
b) so that it draws water by gravity only from a cistern, cylinder or
tank having a permanently open vent pipe, the vertical distance between
the point at which the pipe or pipes supplying water to the fittings is
or are connected to the supply and the spill-over level of any fixed
appliances is not less than 25mm, and the pipe or pipes supply(ies) no
other fitting (other than the draining tap) at a lower level.
IRN 110~
A 'Listed' double check valve or some other no less effective
backflow prevention device shall be fitted to the inlet unless the
shower head is constrained above the spill-over level of the bath,
washbasin or shower tray.
IRN 111~
The fitting is to be so installed as to be readily accessible for
examination, repair, replacement or operation.
IRN 112~
If the shower head is not constrained above the spill-over level of
the bath, wash basin or shower tray, a single check valve or some other
no less effective backflow prevention device must be installed between
the outlet of the fitting and the shower head, or a single check valve
shall be installed at both hot and cold water inlets - Byelaw 17.
Alternatively the fitting shall be installed in accordance with IRN
109b.
IRN 113~
The fitting (s) are only acceptable for servicing purposes and when
installed on a distributing pipe with a static water pressure not
exceeding 1 bar.
IRN 115~
All 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 116~
Sealed primary circuits and/or secondary hot water systems shall
incorporate means for accomodating the thermal expansion of water to
prevent any discharge from the circuit and/or system except in an
emergency situation
IRN 118~
Supplies to primary and secondary circuits shall be from separate
cisterns. No boiler primary circuit shall be connected to a supply
pipe.
IRN 119~
A 'Listed' double check valve or some other no less effective
backflow prevention device shall be fitted to the inlet.
IRN 120~
A 'Listed' single check valve or some other no less effective
backflow prevention device shall be fitted at the inlet where the
fitting is connected to a supply pipe. Water Undertakers cannot be
responsible for any water quality complaints from water passed through
these fittings.
IRN 121~
For use on the supply to one or more adjacent draw-off points only.
These devices are not suitable for use as point-of-entry units to treat
the general supply of water to a building.
IRN 123~
The supply to the storage cistern shall be discharged via a Type A
air gap.
IRN 124~
Plastic tubes and fittings rated for cold water use only shall not be
installed where they may be subject to the effect of external heat.
IRN 125~
For closed circuit use only
IRN 126~
A 'Listed' single check valve or some other no less effective
backflow prevention device shall be fitted at the point of connection(s)
between the supply and the fitting
IRN 128~
The unit shall not be used in surgical or industrial situations
unless supplied via a Type A air gap or an interposed cistern
IRN 129~
Certain water undertakers require the supply to this
fitting/appliance to be by means of a metered supply only, as it is
impracticable to determine or regulate its consumption by the imposition
of design criteria
IRN 130~
Solder alloys containing lead shall not be used in connection with
systems which convey or receive water supplied for domestic purposes.
IRN 131~
Where installed on domestic premises, or elsewhere with the written
consent of the undertakers, the fitting shall be installed with a
'Listed' double check valve or some other no less effective device or,
the fitting shall draw water by gravity only from a cistern by means of
a pipe to which no other draw off tap or fitting is connected downstream
(other than a draining tap) or from which water may be drawn at a lower
level.
IRN 132~
This cistern is not suitable for storing water for domestic purposes.
IRN 133~
No 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.
IRN 134~
The fitting is not suitable for conveying hot water.
IRN 135~
A servicing valve shall be installed at every take-off from a storage
cistern, hot water cylinder or tank.
IRN 136~
A servicing valve shall be installed at the inlet to the fitting.
IRN 137~
A drinking water tap shall be provided upstream of this fitting.
IRN
140~
BIDETS
Byelaw
19 precludes the connection of rim feed or ascending spray type bidets
or bidets with hand-held spray attachments to any supply pipe and Byelaw
20 covers those of over rim type feeds, specifying air gap requirements.
Bylaw 21(1) lays down restrictions concerning supplies to bidets and
other points of draw-off, with Byelaw 21(2) permitting certain
exceptions.
BIDETS
WITH OVER-RIM SUPPLY ARRANGEMENTS
(a) the
requirements of Byelaws 19 and 20 would be accepted as being
Satisfied whenever a bidet is equipped with separate hot and cold taps
and site verification of the air gaps confirms they are in accordance
with the requirements of the table in Byelaw 16(2) – see IRN 109
Such
air gaps can be obtained whenever draw-off taps complying with either BS
5412 or BS 5413 are installed on bidets complying with the appropriate
requirements of BS 5505; part 3 “ vitreous china bidets over-rim supply
only”.
Diagram 1. Over-rim type bidet
Arrangements complying with diagram 1 permit connection either to hot
and cold water distributing pipes or direct to the supply pipe for cold
water and to a supply pipe fed unvented heater for hot water. There are
no restrictions on the taking of feeds from the distributing or supply
pipes to other draw-off taps or water fittings at any level.
(b) in
the case of a bidet equipped with a single outlet ( single flow) mixing
Tap and
side verification confirms the air gap is in accordance with the table
in Byelaw 16(2) – see IRN 109 – hot and cold supplies can be provided by
distributing pipes or direct from the supply pipe as described above.
When the water pressures are balanced there are no restrictions on the
taking of feeds from either the distributing of supply pipes to other
draw-off taps or water fittings at any level.
If the
water pressures are unbalanced , single check valves must be provided in
the pipes supplying the mixer tap.
(c) in
the case of a bidet equipped with a double outlet ( divided flow) mixing
tap the comments given in “a” for separate how and cold taps apply.
BIDETS
WITH ASCENDING SPRAY (OR RIM FLUSH)
(a) the
requirements of Byelaw 21 would be accepted as being satisfied when a
bidet not of the over-rim feed type is connected to an unvented hot
water system if the hot and cold water are supplied via a break pressure
tundish or cistern which provides an air gap meeting with the
requirements of the table in Byelaw 11 ( as in IRN 109) between the
supply pipe and the bidet (see diagram 2).
Diagram 2. Ascending spray type bidet
There
are no restrictions on the taking of feeds to other draw-off taps or
water fittings provided the connections are made upstream of the mixing
valve.
Note:
this arrangement could be used when hot and cold water is provided in
distributing pipes at balanced pressures.
(b)
the requirements of Byelaw 21 would also be accepted as being satisfied
in the following examples of balanced cistern fed systems
(i)
water under cistern pressure is conveyed by separate distributing pipes
which connect to no other tap or appliance other than a feed pipe to
a flushing cistern (see Byelaw 21 (2) ). The hot water heater serves
the bidet only (see diagram 3).
Diagram 3. Ascending spray type bidet
(ii)
water under cistern pressure is conveyed in separate distributing pipes
to the bidet. The separate hot water distributing pipe is connected
above the cylinder to the vent pipe at point a and is fitted with an
additional vent pipe connected to it at point b downstream of a check
valve (see Byelaw 21 (2) (c) (i) Points A and B must be at least 300mm
higher than the spill-over level of the bidet (see diagram 4)
Note:
Certain types of check valve have a high head loss and if the cistern is
at a low level the available pressure at the bidet may be inadequate to
give a satisfactory spray.
Diagram 4. Ascending spray type bidet – with
fittings at a lower level
In this
example there are no restrictions on the taking of supplies to other
points of use at any level provided the water is conveyed in
distributing pipes not connected to those serving the bidet (other than
cold water to a flushing cistern).
(iii)
Water under cistern pressure is conveyed in distributing pipes to the
bidet which is at the lowest point of use. The vented hot water
distributing pipe and the cold water distributing pipe are both
connected at least 150mm higher than the spill-over level of the bidet
(see Byelaw 21 (2) (c) (i) and Byelaw 16 (3) (c). See diagram 5).
Diagram 5. Ascending spray type bidet – no
fittings at a lower level
There
are no restrictions on the taking of supplies to other points of use in
that none can be any lower than the spill-over level of the bidet.
IRN 202~
Certain water undertakers advise that copper cylinders and tanks be
fitted during manufacture with aluminium protector rods to promote
resistance to corrosion.
IRN 203~
Certain water undertakers require aluminium covers to be protected by
a 'listed' paint or lacquer.
IRN 204~
Certain water undertakers accept only galvanised Grade A mild steel
cisterns.
IRN 205~
Certain water undertakers require galvanising to be coated with
'listed' protective paint.
IRN 208~
the installation of a new or replacement flushing cistern
incorporating a dual flush facility not exceeding 9.5 litres is
permitted in all premises until
1st
January 1993. After
1st January 1993
no new installation of a dual flush cistern is permitted.
IRN 209~
Certain water undertakings do not accept galvanising as a suitable
means of internal protection for fittings
IRN 210~
Every WC flushing cistern which gives a nominal flush exceeding 7.5
litres shall operate in the dual flush mode only, and the instructions
for so operating it shall be displayed adjacent to the operating lever.
IRN 211~
Every float-operated valve or other device for controlling the inflow
of water to a storage cistern with a capacity not exceeding 5000 litres
shall be securely and rigidly fixed to that cistern and installed so
that the inflow of water is shut off when the level of water in the
cistern is not less than 25mm below the overflowing level of that
cistern. Where the cistern capacity exceeds 5000 litres, and a device
other than a warning pipe is fitted, the shut off level of the inflow
control device shall be not less than 50mm below the overflowing level.
IRN 302~
Unvented primary circuits may be filled or replenished by means of a
temporary connection between the circuit and a supply pipe porvided a
'listed' double check valve or some other no less effective backflow
prevention device is permanently connected at the inlet to the circuit
and the temporary connection is removed after use
Fittings manufactured from duplex (alpha-beta) brass are not
acceptable for underground use and certain water undertakers also
restrict their use above ground.
WATERHAMMER AND FITTINGS WHICH CONTROL FLOW
Byelaw 54 requires every pipe to be adequately supported and secured
to avoid any damage from airlock or reverberation.
Whilst there is no documentary evidence to show the magnitude and
extent of waste of water in consumers’ premises as a consequence of
waterhammer, there is no doubt that sudden excessive pressure rises
within pipework could lead to premature failure of jointing and possible
damage to connected fittings. In cases where unacceptable waterhammer
occurs when particular fittings or appliances are used, suitable
measures should be taken which could include the fitting of air or gas
loaded vessels or special mechanical waterhammer arresters.
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