72
1
10 Installation type and size
10.1 Wet pipe installations
10.1.1 General
Wet
pipe
installations
are
permanently
charged
with
water
under
pressure.
Wet
pipe
installations
should
be installed
only
in
premises
where
there
is
no
possibility
of
frost
damage,
and
where
the
ambient
temperature will
not
exceed
95°C.
Only
wet
pipe
installations
shall
be
used
for
grid
and
loop
systems.
10.1.2 Protection against freezing
Pipework
subject
to
freezing
may
be
protected
by
anti-freeze
liquid
or
electrical
trace
heating
or
subsidiary
dry
pipe
or
alternate
extensions.
NOTE
1:
the
size
of
any
one
anti-freeze
extension
should
not
exceed
20
sprinklers.
NOTE
2:
the
total
number
of
sprinklers
on
anti-freeze
extensions
should
not
exceed
100.
An
anti-freeze
solution
shall
be
prepared
with
freezing
point
below
the
expected
minimum
temperature
for the
locality
(see
clause
18.3.3).
In
the
case
of
a
trace
heating
system,
the
piping
shall
be
provided
with
non-combustible
insulation. Duplicate
heating
elements
shall
be
provided
over
the
complete
length
of
the
affected
pipework.
Even
in
the case
of
a
failure
of
one
of
the
two
heating
elements
a
minimum
temperature
of
5°C
shall
be
maintained. Each
circuit
shall
be
electrically
monitored
and
triggered
by
separate
temperature
sensors.
The
trace
heating
system
shall
be
monitored
for
power
supply
failure
and
failure
of
the
heating
elements
or sensors.
For
subsidiary
dry
pipe
or
alternate
extensions,
see
10.5.
Table 19: Maximum number of sprinklers per installation - wet pipe and pre-action installations
Maximum
number
of
sprinklers
including
any
LH
sprinkler
including any
OH
and
LH
sprinklers
000,
except
as
allowed
in
Annexes
D
and
F
000
10.1.3 Sprinkler orientation
Where
possible
the
sprinklers
shall
be
fitted
in
the
upright
position
to
avoid
mechanical
damage
and
the
collection
of
foreign
matter
in
the
sprinkler
fittings
and
to
make
it
easier
to
drain
the
pipe
network.
10.1.4 Size of installations
The
number
of
sprinklers
to
be
controlled
by
a
wet
alarm
valve,
including
any
sprinklers
in
a
subsidiary
extension,
shall
not
exceed
that
shown
in
Table
19.
10.2 Dry pipe installations
To Next Page
Loading...