If it is desired to allow the hand spray
to be used inside say a bathtub or a
basin it is essential that double check
valves be fitted to the inlet on both
hot and cold supplies to the thermo-
static valve. Alternatively single check
valves can be fitted at the inlets and
an additional check valve should be
fitted in the valve outlet.
No check valves need be fitted if
the hand spray is prevented from
reaching closer than 25mm of the
spill over level of any such fixture.
CATEGORY 5 RISK
Water in a Sink, WC or Bidet is
considered to be a fluid category 5
risk which is a fluid which represents
a serious health hazard if it were to
find it’s way back into the supply
pipe. For this reason it must not be
possible for any flexible shower head
to be able to enter any adjacent Sink,
WC or Bidet. If the flexible hose to be
fitted could reach into any such
vessel, the requirements to the
system design are so onerous it is
better not to fit a flexible. Rather, a
fixed overhead showerhead should
be considered. (See Figure 4).
It will also be seen that this risk could
change should the hose be taken out
of the restraining device or should a
longer replacement hose be fitted at
a later date. Installers and house-
holders are advised to take account
of these factors when fitting replace-
ment hoses.
For pumped applications the pipe
supplying the pump must not in
addition supply an ascending spray
bidet.
Figure 3 Illustration of backflow risk from fluid
Category 3 risk
WATER REGULATIONS
3
Figure 4 Illustration of backflow risk from fluid
Category 5 risk
trevi showers.qxd 04/12/03 13:21 Page 4
