10
3.6
Snow
Shielding
In
areas
of
high
snowfall,
snow
shields
should
be
installed
on
air
inlets
and
outlets
to
prevent
snow
from
entering
the
units.
Additionally,
the
height
of
the
base
structures
should
be
increased
so
as
to
raise
the
units
further
off
the
ground.
Figure
3
‐
3.11:
Outdoor
unit
snow
shielding
4
Refrigerant
Piping
Design
4.1
Design
Considerations
Refrigerant
piping
design
should
take
account
of
the
following
considerations:
The
amount
of
brazing
required
should
be
kept
to
a
minimum.
On
the
two
inside
sides
of
the
first
indoor
branch
joint
(“A”
in
Figures
3
‐
4.2
and
3
‐
4.3)
the
system
should,
as
far
as
possible,
be
equal
in
terms
of
number
of
units,
total
capacities
and
total
piping
lengths.
4.2
Material
Specification
Only
seamless
phosphorus
‐
deoxidized
copper
piping
that
complies
with
all
applicable
legislation
should
be
used.
Temper
grades
and
minimum
thicknesses
for
different
diameters
of
piping
are
specified
in
Table
3
‐
4.1.
Table
3
‐
4.1:
Piping
temper
and
thickness
Piping
outer
diameter
(mm)
Temper
1
Minimum
thickness
(mm)
Ф6.35
O
(annealed)
0.8
Ф9.53
0.8
Ф12.7
0.8
Ф15.9
1.0
Ф19.1
1.0
Ф22.2
1/2H
(half
hard)
1.2
Ф25.4
1.2
Ф28.6
1.3
Ф31.8
1.5
Ф38.1
1.5
Ф41.3
1.5
Ф44.5
1.5
Ф54.0
1.8
Notes:
1.
O:
coiled
piping;
1/2H:
straight
piping.
Snow shield for air outlet
Snow shield for air inlet
Snow shield for air inlet
