6
T
T
H
HE
ER
RM
MO
OS
ST
TA
AT
TIIC
C
M
M
I
IX
XIIN
NG
G
V
V
A
AL
LV
VE
ES
S
SYMBOLS
Hot water
Water hammer arrestor
Safety valve
Drain
Cold water
Stop valve
Pump
Pressure reducing valve
Mixed water
Non-return valve
Isolating valve
Flow direction
Water drain cock
Thermostatic
Adjustment valve
mixing valve
Statutory calculation
Calculation of the loop's
pump flow capacity =
The flow is calculated according to calorific losses on the
surface of the whole piping, it depends on the thickness of the
isolation.
Loss "P" :
P = L.k. (te - ta) P in w, L in m,
K : coef k (insulating)
(this coefficient varies according to the diameter
and the nature of the pipe),
t e : temperature of sanitary hot water,
t a : room temperature
(for example : +10°C in the basement, +20°C upstairs).
This discharge is usually determined according to a
T near 5°C.
t r : temperature of the return, will never be less than 50°C.
td : starting temperature.
P (Kw)
1,163 (td - tr)
Q (m3/h) = _____________
A
B
C
D
E
F
G
Key points of the regulation :
- Increased hot temperature from the heater (use water heaters with minimal or no
storage)
- Use of recirculation systems : circulating loop and balancing valves
- Ensure that the target temperature is achieved throughout all levels of the loop.
- Circulating loop should be designed to return the mixed water to the storage not
less than 55°C*.
- Mixing valves must be as close as possible to the point of use.
- Mixing valves must have integrated check-valves.
- Mixing valves must allow easy cleaning and disinfection operation.
- Dismantle and clean hoses, tap, showerheads and mixing valves minimum once a
year.
- Hot and cold water distribution pipes must be insulated sufficiently (never together).
* according to National Regulation
Flow diagram for a "multi-levels"
complete mixed water circuit
VM : micrometer valves to stabilize
circuit temperature.
VM1 A : Open between 70 and 90%.
VM1 B : Open between 30 and 10%.
Remark : If there is a connection point on the boiler (R) the return circuit
should be connected here (A).
Recycling of the loop : with a minimum of six times
the mixed water's volume per hour.
Delivery of the pump : total manometric height,
minimum 4 meters + head loss of the loop.
THE " MULTI-LEVELS " APPROACH
THE RIGHT TEMPERATURE FOR EACH APPLICATION
Table 1
Development of legionella according to water temperature
<20°C / 69°F
___________________
lethargic state
20-46°C / 68-115°F
________
growth (no multiplication from 47°C on)
50°C / 122°F
___________________
90% of bacteria will die in a period of 2 hours
60°C / 140°F
___________________
90% of bacteria will die in 2 minutes
80°C / 178°F
___________________
90% of bacteria will die in less of 1 minute
Table 2
Relation between the canalization's capacity and its length *
Material
Dimensions of the pipe Length in meters leading to
a capacity of 3 litres
Copper
15 x 1
22 m
18 x 1
15 m
22 x 1
9 m
Galvanized steel
DN 15
15 m
DN 20
8 m
Plastic pipe PEX/PER
15 x 2,5
39 m
18 x 2,5
23 m
Plastic PP
20 x 1,9
14 m
25 x 1,9
9 m
*Source : CSTC Belgium Nov. 2002. The canalization's capacity is the inner section
multiplied by the length.
Please also consult the calculation model and practical rules on page 7.
A
B
C
D
E
F
F
F
G
E
G
+
+
G
*
according to National Regulation
Volume inferior or equal to 3
litres between the
distribution point and the
most distant point of use
(shower), see table 2.