Ariston Contract STI 300 indirect, Инструкция по установке

Страница: 11 / 24

11
consideration should be given to the installation of an
electronically operated device to war n when discharge takes
place. Note: The discharge will consist of scalding water and
500mm Max.
300mm
Min.
Temperature & pressure
relief valve Metal discharge pipe (D1) from
temperature & pressure relief valve.
to tundish.
Metal discharge pipe (D2) from tundish
with continuous fall. See Table 2 and worked
example.
Tundish
Fixed grating
Trapped gulley
Discharge below
fixed grating.
(see page 10 for
alternative points
of discharge).
Valve outlet size Minimum size of
discharge pipe D1*
Minimum size of
discharge pipe D2*
from tundish
Maximum
resistance allowed,
expressed as a
length of pipe (i.e.
no elbow or bends)
Resistance created
by each elbow or
bend
G 1/2 15mm 22mm
28mm
35mm Up to 9m
Up to 18m
Up to 27m
0.8m
1.0m
1.4m
G 3/4 22mm 28mm
35mm
42mm Up to 9m
Up to 18m
Up to 27m
1.0m
1.4m
1.7m
G 1 28mm 35mm
42mm
54mm Up to 9m
Up to 18m
Up to 27m
1.4m
1.7m
2.3m
T
ABLE
2. Sizing of copper discharge pipe “D2” for common temperature valve outlet sizes.
WORKED EXAMPLE
The example below is for a G 1 /
2
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 T
ABLE
2;
Maximum resistance allowed for a straight length of 22mm copper discharge
pipe (D2) from G
1 /
2
temperature & pressure 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
1 /
2
temperature & pressure 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.
F
IG
. 2.9