Suggested Ways Of Terminating Discharging Pipes Safety; Worked Example - Ariston STD 100 DIRECT User Manual

FIG. 6
300L AND 500LONLY
FROM BRONZE
PUMP
DRAIN
FLOW
RETURN
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SECONDARY
RETURN
NON-RETURN
SUGGESTED WAYS OF TERMINATING
DISCHARGING PIPES SAFETY
Temperature & pressure Metal discharge pipe (D1) from
relief valve temperature & pressure relief valve.
to tundish.
500 mm Max.
300 mm
Min.
Metal discharge pipe (D2) from tundish
with continuous fall. See Table 2 and worked
example.
Table 2. Sizing of copper discharge pipe "D2" for common temperature valve outlet sizes.
Valve outlet size Minimum size of
discharge pipe D1*
G ½ 15 mm
G ¾ 22 mm
G 1 28 mm

WORKED EXAMPLE

The example below is for a G ½ Temperature & Pressure Relief valve with a discharge pipe
(D2) having 4 no. elbows and length of 7m from the Tundish to the point of discharge.
From Table 2
Maximum resistance allowed for a straight length of 22mm copper discharge pipe (D2) from G
½ T & P valve is 9m.
Subtract the resistance for 4 no. 22mm elbows at 0.8m each = 3.2m.
Therefore the maximum permitted length equates to: 5.8m.
As 5.8m is less than the actual length of 7m therefore calculate the next largest size.
Maximum resistance allowed for a straight length of 28mm pipe (D2) from G ½ T & P valve
equates to: 18m.
Subtract the resistance for 4 no. 28mm elbow at 1.0m each = 4m.
Therefore the maximum permitted length equates to: 14m
As the actual length is 7m, a 28mm (D2) copper pipe will be satisfactory.
y y y y
FIG. 7
y y y y
Tundish
y y
Discharge below
fixed grating.
y y y y (see page 6 for
alternative points
of discharge).
Fixed grating
Trapped gulley
Minimum size of Maximum Resistance created
discharge pipe D2* resistance allowed, by each elbow or
from tundish expressed as a
length of pipe (i.e.
no elbow or bends)
22 mm Up to 9 m
28 mm Up to 18 m
35 mm Up to 27 m
28 mm Up to 9 m
35 mm Up to 18 m
42 mm Up to 27 m
35 mm Up to 9 m
42 mm Up to 18 m
54 mm Up to 27 m
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bend
0.8 m
1.0 m
1.4 m
1.0 m
1.4 m
1.7 m
1.4 m
1.7 m
2.3 m