Roxul Industrial Insulation Process - Manual (Page 43)

1.2.7 Insulation of valves and flanges
Heat loss incurred through non insulated fixtures
such as valves and flanges are substantial, even at
low temperatures. An uninsulated valve located
outside loses as much heat at 250 °F (120 °C) as
100 ft (30.5 m) of uninsulated piping. The
temperature of the medium can also decrease to
such an extent at non-insulated fittings or flanges,
that process critical temperatures are reached, at
which point for example, the medium will start to
crystallize. Valves and flanges should therefore be
insulated as much as possible. To avoid damage
during inspection or repairs, the insulation for
valves and flanges is designed with removable
coverings or hoods, to allow rapid disassembly.
Removable coverings or hoods are usually
insulated from the inside with wired mats or
flexible ProRox
® insulation (FSL Series). The
coverings are fastened to the object with lever
fastenings, which are fixed directly onto the
covering or on to straps. Take the following
conditions into account when designing insulated
coverings for fittings and flanges:
The overlap distance of the insulated covering
over the insulated pipe should be at least 2"
(50 mm).
The pipe insulation should end at the flanges,
leaving a gap equal to the bolt length +1.2"
(30 mm) and should be closed off with a lock
washer so the flange can be loosened without
damaging the insulation.
With valves, an extended spindle should
preferably be fitted horizontally or below the
pipe to prevent leakage along the spindle shaft.
The cladding must be fitted to prevent the
ingress of moisture in the insulation. On
inclined or vertical piping, for example, mount
rain deflectors above the removable coverings.
If the ingress of moisture into the insulation is
unavoidable, make 0.4" (10 mm). diameter drain
holes in the removable covering.
1.2 Insulation of piping
1. Pipe - 2. ProRox ® insulation -
3. Cladding - 4. Sheet-metal screw or Rivet -
5. Swage - 6. Drainage opening -
7. Strap - B ≥ 2" (50 mm) - A = bolt length + 1.2" (30 mm)
1. Pipe - 2. ProRox ® insulation - 3. Cladding - 4. Sheet-
metal screw or rivet - 5. Rain deflector - 6. Lock washer
- 7. Straps - 8. Rain deflector -
B ≥ 2" (50 mm) - A = bolt length + 1.2" (30 mm)
2"
(50 mm
)
5
0.8"
(20 mm)
A number of possible design options for insulation
systems for pipe fittings and flanges follow:
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