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.
- Crown Duct Slab Plus is a strong rigid slab of glass mineral
wool of 48 kg/m3 nominal density with a bright Class ‘O’ reinforced
aluminium facing.
- Icerock Ductwrap is a flexible roll of non-combustible rock
mineral wool of 45 kg/m3nominal density with a bright
Class ‘O’ reinforced aluminium foil facing on one side.
Typical Construction
Crown Duct Roll, Crown Duct Slab
Plus and Icerock Ductwrap are suitable for the thermal and acoustic
insulation of square and rectangular:
- air conditioning and warm air ducting
- extract ducts
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
Crown Duct Roll and Icerock Ductwrap
Cut the Crown Duct Roll or Icerock Ductwrap into lengths, taking
into account the thickness of the insulation, which should be added
to the duct dimensions in accordance with the following
formulae:
Length = 2a + 2b + 8t
where:
a is the external width of the duct
b is the external height of the duct
t is the insulation thickness.
Bond the insulation to the ductwork using a suitable adhesive
applied in accordance with the manufacturer’s instructions.
Adhesive may be applied as a continuous film over the entire
surface of the ductwork or discontinuously as bands at
approximately 400mm centres.
Seal all insulation joints with a
matching soft aluminium self adhesive tape at least 100mm wide. The
insulation may be further secured with galvanised hexagonal wire
mesh netting wrapped around the outside. The netting should be
laced together with suitable wire.
Care must be taken when applying
the wire netting to avoid puncturing the bright Class ‘O’ facing.
Use piercing fasteners 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.
Crown Duct Slab Plus
Cut the Crown Duct Slab Plus so that the top and bottom pieces
overlap the combined width of the duct and side insulation. Bond
the insulation to the ductwork by means of a suitable adhesive, in
accordance with the manufacturer’s instructions.
Secure the insulation on the underside of ductwork by means of
suitable insulation hangers spaced at maximum 300mm centres in a
square pattern. Close butt all the junctions between pieces of
insulation and seal with self adhesive aluminium tape at least
100mm wide.
Performance
Operating temperatures
Crown Duct Roll, Crown Duct Slab
Plus 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. The surface
temperature of the facing should not exceed 80°C.
Fire performance
The base glass mineral wool of Crown Duct Roll, Crown Duct
Slab Plus and the base rock mineral wool of Icerock Ductwrap are
classified as non-combustible 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 and 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.
Thermal performance
The thermal conductivity of the insulation varies with
temperature, as shown in the table below. Insulation thicknesses
should be set by the specification, but otherwise meet the
recommendations given in
BS 5422: 2001..
| Mean temperature
(ºC) |
Thermal
conductivity (W/mK) |
|
|
Crown Duct
Roll |
Crown Duct Slab
Plus |
Icerock
Ductwrap |
| 10 |
0.033 |
0.030 |
0.033 |
| 25 |
0.035 |
0.032 |
0.035 |
| 50 |
0.039 |
0.035 |
0.039 |
| 75 |
0.046 |
0.039 |
0.045 |
| 100 |
0.052 |
0.044 |
0.050 |
| 125 |
0.059 |
0.049 |
0.056 |
Note: Tested
in accordance with BS 874: 1973 (1980)
Acoustic performance
Noise transmitted to the working environment can be
effectively controlled by the application of Crown Duct Roll, Crown
Duct Slab Plus 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
Product Selector - square or rectangular air
conditioning and warm air ductwork
| Application |
Level |
Product |
Specification reference |
| Internal ductwork |
High |
Crown Duct Roll |
D1 |
| Low |
Crown Duct Slab Plus or Icerock Ductwrap, finished with sheet
metal |
D2 |
| External and in boiler houses and plant rooms |
High or Low |
Crown Duct Slab Plus or Icerock Ductwrap, finished with sheet
metal |
D2 |
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.