Ideal-Standard Ceratherm C100 A7537AA User Manual

7
7
CATEGORIES OF RISK
The water regulations published in 1999* take a new approach to backow in that they look at di󰀨erent
categories of risk. The installer must assess the risk from the various categories of uid in adjacent
appliances before determining the level of backow protection required for a particular installation.
Figures 3 & 4 describe the protection required in various installations.
CATEGORY 3 RISK
Water in a shower tray, basin or bathtub is considered to be a uid category 3 risk which is a uid
which represents a slight health hazard if it were to nd it’s way back into the supply pipe. For this
reason it must not be possible for any exible shower head to be able to enter any adjacent washba-
sin, bath or shower tray unless appropriate protection is employed. (See Figure 3). 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 tted to the inlet on both hot and cold supplies to the thermostatic valve. Alternatively single check
5 WATER REGULATIONS
zone of backflow
risk for longer
hose
spill
over
level
bath or shower tray
25mm minimum air gap
required if check valves are
not fitted
spill over
level
washbasin
zone of
backflow risk
for shorter
hose
no additional
backflow protection
required
cold and hot water supplies
to shower valve will need
additional check valves on each
service if longer hose is fitted
zone of backflow risk
for restrained hose
which is longer than
system design hose
- not permitted -
zone of backflow
risk for unrestrained
hose
zone of backflow risk
for restrained hose
w.c.
spill-over
level
shower tray
or bath tub
bidet
w.c.
spill-over
level
restrained hose giving
the 25 mm air gap is
permitted
25mm
minimum
unrestrained
hose would
not be
permitted
valves can be tted at the inlets and an
additional check valve should be tted
in the valve outlet.
No check valves need be tted if the
hand spray is prevented from reaching
closer than 25mm of the spill over level
of any such xture.
CATEGORY 5 RISK
Water in a Sink, WC or Bidet is con-
sidered to be a uid category 5 risk
which is a uid which represents a
serious health hazard if it were to nd
it’s way back into the supply pipe. For
this reason it must not be possible for
any exible shower head to be able to
enter any adjacent Sink, WC or Bidet. If
the exible hose to be tted could reach
into any such vessel, the requirements
to the system design are so onerous it
is better not to t a exible. Rather, a
xed 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 tted at a
later date. Installers and householders
are advised to take account of these
factors when tting replacement hoses.
For pumped applications the pipe
supplying the pump must not in addition
supply an ascending spray bidet.
Fig. 3 Backow risk from a uid category 3
Fig. 4 Backow risk from a uid category 5

Ideal-Standard Ceratherm C100 A7537AA Specifications

General

Brand	Ideal-Standard
Model	Ceratherm C100 A7537AA
Category	Plumbing Product
Language	English