Products
- Crown Duct Roll is a flexible but compression resistant roll of
glass mineral wool of 28 kg/m3 nominal density, with a
bright Class ‘O’ reinforced aluminium facing.
- Icerock Ductwrap is a strong flexible roll of rock mineral wool
of 45 kg/m3 nominal density, with a bright Class ‘O’ reinforced
aluminium facing.
Typical Construction
Crown Duct Roll and Icerock
Ductwrap are suitable for the thermal and acoustic insulation of
round and oval:
- air conditioning and warm air ducting
- extract ducts
The unique nature of Icerock
Ductwrap makes it particularly suitable for
lagging small diameter ductwork.
The product selector sets out the most common recommended ductwork
finishes for a range of applications. For external ductwork or for
ductwork at low level, sheet metal finishes provide protection.
Installation
Cut the insulation into lengths,
taking into account its thickness, which should be added to the
duct dimensions in accordance with the following
formulae:
Length = 3.14 x (od + 2t)
where:
od is the outside diameter of the duct
t is the insulation thickness.
The insulation should be cut to the appropriate length as described
above and bonded to the ductwork using a suitable adhesive in
accordance with the manufacturer’s instructions. Adhesive may be
applied as a continuous film over the entire surface of the
ductwork or as bands at approximately 400mm centres. All insulation
joints should be sealed and secured with a matching soft aluminium
self adhesive tape of 100mm minimum width.
The insulation may be further secured with galvanised hexagonal
wire mesh netting wrapped around the outside. The netting
dimensions should be laced together with suitable wire. Care must
be taken when applying the wire netting to avoid puncturing the
bright Class ‘O’ facing. Piercing fasteners should be used at 300mm
maximum centres on the underside of rectangular ductwork to provide
additional support. Where the piercing fasteners puncture the
bright Class ‘O’ facing, they should be sealed with aluminium tape
to maintain the vapour control layer.
Performance
Operating temperatures
Crown Duct Roll can be used up to continuous operating
temperatures of 230°C and down to below ambient temperatures
provided that a 100% vapour barrier is maintained. The surface
temperature of the facing should not exceed 80°C. Icerock Ductwrap
can be used up to continuous operating temperatures of 200°C and
down to below ambient temperatures provided that a 100% vapour
barrier is maintained.
Thermal performance
The thermal conductivities of Crown Duct Roll and Icerock
Ductwrap vary with temperature, as shown in the table
below.
| Mean temperature
(ºC) |
Thermal
conductivity (W/mK) |
| Crown Duct
Roll |
Icerock
Ductwrap |
| 0 |
- |
0.032 |
| 10 |
0.033 |
0.033 |
| 25 |
0.035 |
0.035 |
| 50 |
0.039 |
0.039 |
| 75 |
0.046 |
0.045 |
| 100 |
0.052 |
0.050 |
| 125 |
0.059 |
0.056 |
| 150 |
- |
0.062 |
Note: Tested
in accordance with BS
874: 1973 (1980) Insulation thicknesses should be set by the
specification, but otherwise meet the recommendations given in
BS 5422: 2001.
Fire performance
The base glass mineral wool and rock mineral wool of Crown Duct
Roll and Icerock Ductwrap is classified as noncombustible to
Euroclass A1 to BS EN
ISO
13501-1, to BS 476:
Part 4: 1970 (1984) and Class 1 surface spread of flame to
BS 476: Part 7: 1997.
The glass mineral wool, the rock mineral wool and the foil facing
comply with the Class ‘O’ requirements of the Building Regulations
when tested to BS 476:
Part 6: 1989 and Part 7: 1997.
Acoustic performance
Noise transmitted to the working environment can be effectively
controlled by the application of Crown Duct Roll and Icerock
Ductwrap. The actual performance level will vary dependant on the
type and thickness of the surface finish.
Other Advantages
- Combines lightness, strength and ease of use
- The aluminium foil facing ensures a positive vapour seal
- Corrosion free
- No deterioration of performance over time
- Resilient, strong and flexible
Economic thickness of insulation on ductwork
carrying warm air
| Temperature difference between air inside duct
and ambient still air (Cº) |
Economic thickness of insulation (mm) |
| 10 |
40 |
| 25 |
50 |
Note: These figures are derived from
BS 5422: 1990 and
assume a thermal conductivity of 0.033 W/mK for the
insulation.
Product Selector - round or oval air conditioning
and warm air ductwork
| Application |
Level |
Product |
Specification reference |
| Internal ductwork |
High |
Crown Duct Roll or Icerock Ductwrap |
D1 |
| Low |
Crown Duct Roll* or Icerock Ductwrap*, finished with sheet
metal |
D2 |
| External and in boiler houses and plant rooms |
High or Low |
Crown Duct Roll*, or Icerock Ductwrap*, finished with sheet
metal |
D2 |
| Note: * Crown Duct Roll and
Icerock Ductwrap are suitable in these applications where the
insulation is not required to provide any mechanical support to the
metal casing. |