THE THICKNESS

OF ROCKWOOL
INSULATION
In accordance with BS5422:2009
 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

OVERVIEW BS5422:2009 An explanatory note

BS5422:2009 Method for specifying thermal insulating materials for pipes, tanks,
vessels, ductwork and equipment operating within the temperature range -40ºC to
BS 5422:2009 is the industry wide standard for +700ºC.
determining and specifying the requirements for BS 5422 is arguably the most important industry-wide standard for determining
and specifying the requirements for thermal insulation used on pipe-work and
thermal insulation to pipework & equipment. equipment. Importantly, the appropriate insulation thicknesses taken from BS 5422
and used on pipe-work will be eligible for enhanced capital allowances (ECAs).
BS 5422 - Method for specifying thermal In January 2009, BS 5422:2001 was superseded by BS 5422:2009. The new version
insulating materials for pipes, tanks, vessels, of this standard is relevant to H&V and process work undertaken on sites across
the UK, although additional factors may apply to building works undertaken
ductwork and equipment operating within in accordance with the Building (Scotland) Regulations, which still refer to
BS5422:2001 as outlined below.
the temperature range of –40°C to +700°C
One of the most significant changes to BS 5422 is that the thicknesses of insulation
- Thicknesses calculated for services and shown for pipe-work, ducts, plant and equipment are based on ‘practical limits’
for all applications. For H&V applications, BS 5422 has adopted the thicknesses
equipment under BS 5422:2009 are based on of insulation published by TIMSA (Thermal Insulation Manufacturers and Suppliers
Association) as part of its ‘guidance for achieving compliance with Part L of the
practical limits for all applications. Building Regulations - DOMESTIC AND NON-DOMESTIC HEATING, COOLING
AND VENTILATION GUIDE’ (relevant to England, Wales and Northern Ireland).
For H&V applications, BS 5422 has adopted It should be noted that the Scottish Building Standards Authority (SBSA) Editions
thicknesses of insulation published by TIMSA of the Technical Handbooks (Domestic & Non–Domestic) to the Building Standards
(Scotland) Regulations 2015, Sections 6, Energy, refer directly to BS 5422:2009.
(Thermal Insulation Manufacturers & Suppliers
BS 5422 is not a prescriptive document and recognises that there are many reasons
Association ) as part of its guidance for achieving why the insulation of pipes, tanks, vessels, ductwork and equipment may be
required. It is therefore important that specifiers state the criteria or specific clause
compliance with Part L of the building regulations. or reference in this standard in any specification.

Insulation thicknesses are given for a range of thermal conductivities appropriate to

HVAC equipment insulation is CE marked to BS the usual materials used for the application; thicknesses for intermediate thermal
EN 14303 for application temperatures up to conductivities and pipe sizes may be deduced by calculation or interpolation For
guidance in selecting appropriate types of insulation and suitable methods of
230ºC. application, reference should be made to BS 5970.

ROCKWOOL stone wool does not thermally age and therefore the thicknesses
shown can be relied upon to provide the required insulation performance for the
lifetime of the host structure.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Surface emissivity (ε) table

Material Emissivity (ε)

Aluminium, bright 0.05

Aluminium, oxidized 0.13

Aluminium foil, bright reinforced 0.05

Aluminium foil, polyester faced reinforced 0.40

Alu-zinc 0.18

Austenitic steel 0.15

Brass, dull tarnished 0.61

Brass, unoxidized 0.035

CE Marking pH Neutrality
With the introduction of the ROCKWOOL insulation is chemically Cast iron (and iron) 0.35
Construction Products Regulation (CPR), compatible with all types of pipes,
CE marking has become mandatory for equipment and fittings. (Guidance Cast iron, rusted and oxidized 0.65
all construction products covered by a is given in BS5970 regarding the
Chrome, polished 0.10
harmonised technical specification as of treatment of austenitic stainless steel
1st July 2013. pipework and fittings). Stone wool Cloth 0.90
insulation is chemically inert. A typical
This regulation is an EU law and has aqueous extract of ROCKWOOL Copper, commercial scoured to a shine 0.07
been adopted by all member states insulation is neutral or slightly alkaline
including the United Kingdom. It is now (pH 7 to 9.5). Copper, oxidized 0.70
illegal to sell any products covered by
a harmonized European standard which Durability Copper, polished 0.02
are not CE marked accordingly. ROCKWOOL stone wool insulation
products have been proven in service Fire brick 0.75
This new approach standardises the key for over 60 years, in a wide range of
features of technical insulation materials Galvanised steel, blank 0.26
climates and degrees of exposure.
(e.g. thermal conductivity, reaction to ROCKWOOL insulation will generally Galvanised steel, dusty 0.44
fire, mechanical characteristics etc.) perform effectively for the lifetime of the
and ensures an accurate comparison of building, plant or structure. Paint, black 0.95
products across the market.
Biological Paint, other colours 0.90
ROCKWOOL has been CE marking ROCKWOOL stone wool is a naturally
products for the construction industry inert and rot-proof material that does Paint, white 0.85
in the UK since 2002, constantly not encourage or support the growth
introducing more and more of of fungi, moulds or bacteria, or offer Paint, aluminium weathered 0.55
its product range each year as sustenance to insects or vermin.
requirements change. The exceptions Paint, aluminium new 0.30
are those products which are not
Roofing felt 0.94
currently covered by a harmonised
European Standard. Rubber black 0.95
ROCKWOOL is committed to gaining Rubber, grey 0.85
all the necessary certification and
accreditation of its products to comply Steel 0.35
with the regulations set by the EU law.
Steel, black painted 0.90

Steel, oxidized 0.80

White lacquer 0.95

NOTE 1 The above values provide a useful guide to surface emissivity. However, it should be noted that the
emissivity of a material varies with temperature and surface finishes. Therefore, the precise emissivity should
be ascertained where a high degree of accuracy is required.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Surface emissivity Guide to tables

Emissivity is defined as the ratio of the energy radiated from a material’s surface to
that radiated from a blackbody (a perfect emitter) under the same conditions. BS5422 table Table reference Page no.

It is a dimensionless number between 0 (for a perfect reflector) and 1 (for a perfect Minimum insulation thickness for chilled and cold water steel pipes to control
emitter). The emissivity of a surface depends not only on the material but also on 6 condensation on a high emissivity outer surface (0.9) with an ambient temperature of 9
the nature of the surface. For example, a clean and polished metal surface will have +25°C and a relative humidity of 80%
a low emissivity, whereas a roughened and oxidised metal surface will have a high Minimum insulation thickness for chilled and cold water copper pipes to control
emissivity. The emissivity also depends on the temperature of the surface. 7 condensation on a high emissivity outer surface (0.9) with an ambient temperature of 10
+25°C and a relative humidity of 80%
Knowledge of surface emissivity is important for accurate heat transfer calculations.
Minimum insulation thickness for chilled and cold water steel pipes to control
So what does this mean to me? 8 condensation on a low emissivity outer surface (0.05) with an ambient temperature of 11
Low emissivity surfaces (e.g. aluminium, stainless steel etc.) produce a higher +25°C and a relative humidity of 80%
surface temperature but lower heat loss than high emissivity surfaces (e.g. painted
steel, cloth etc.) when compared at the same operating conditions and insulation Minimum insulation thickness for chilled and cold water copper pipes to control
thickness. 9 condensation on a low emissivity outer surface (0.05) with an ambient temperature of 12
+25°C and a relative humidity of 80%
Consider a 169 mm O.D. hot water pipe running at 75°C with an ambient
temperature of 15°C insulated with 50 mm thick RockLap H&V Pipe Section: Indicative thickness of insulation for cooled and chilled water systems to control heat
10 13
gain – Low emissivity outer surfaces
Based on ambient temperature 20°C (still air), horizontal pipe.
Indicative thickness of insulation for cooled and chilled water systems to control heat
11 14
gain – High emissivity outer surfaces
Other surface
Material Emissivity (ε) temp (oC) Heat loss (W/m) Minimum insulation thickness for condensation control on ductwork carrying chilled air
12 15
in ambient conditions: indoor still air temperature
Aluminium 0.05 28.8 25
13 +25°C, relative humidity 80%, dewpoint temperature 21.3°C 16
Cloth 0.90 24.0 27
14 Indicative thickness of insulation for ductwork carrying warm air to control heat loss 17
For personnel protection applications, high emissivity claddings are best.
Indicative thickness of insulation for chilled and dual-purpose ducting to control heat
15 18
For heat conservation, low emissivity claddings are best. transfer

Indicative thickness of insulation for non-domestic heating services to control heat loss
16 19
– Low emissivity outer surfaces

Indicative thickness of insulation for non-domestic heating services to control heat loss
17 20
– High emissivity outer surfaces

Indicative thickness of insulation for non-domestic hot water service areas to control
18 21
heat loss – Low emissivity outer surfaces

Indicative thickness of insulation for non-domestic hot water service areas to control
19 22
heat loss – High emissivity outer surfaces

Indicative thickness of insulation for domestic heating and hot water systems having
20 23
low emissivity outer surfaces

Minimum insulation thickness to control the surface temperature of a non-metallic

22 24
surface with a surface emissivity of 0.90 and design cold face temperature of 59°C

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

BS5422 table Table reference Page no. Table 6 (BS5422:2009)

Minimum insulation thickness to control the surface temperature of a metallic surface Minimum insulation thickness for chilled and cold water steel pipes to control
23 25 condensation on a high emissivity outer surface (0.9) with an ambient temperature
with a surface emissivity of 0.05 and design cold face temperature of 50°C
of +25°C and a relative humidity of 80%
Minimum insulation thickness to control the surface temperature of a non-metallic
24 26
surface with a surface emissivity of 0.90 and design cold face temperature of 50°C Temperature of contents (ºC)
Outside diameter Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
Minimum insulation thickness to control the surface temperature of a metallic surface
24 27 of steel pipe on
with a surface emissivity of 0.05 and design cold face temperature of 55ºC +10 +5 0
which insulation
Minimum insulation thickness to control the surface temperature of a metallic surface has been based Calculated Advised Calculated Advised Calculated Advised
24 28 (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm)
with a surface emissivity of 0.18 and design cold face temperature of 55°C

Minimum insulation thickness to control the surface temperature of a metallic surface 17 8 20 11 20 14 20

24 29
with a surface emissivity of 0.26 and design cold face temperature of 55°C 21 9 20 12 20 15 20
Heat loss from bare surfaces calculated in accordance with BS EN ISO 12241:2008 27 9 20 13 20 16 20
25 30
(black steel pipes)
33 10 20 13 20 16 20
Heat loss from bare surfaces calculated in accordance with BS EN ISO 12241:2008
26 31 42 10 20 14 20 17 20
(copper pipes – commercial grade, scoured to a shine)
48 10 20 14 20 18 20
Heat loss from bare surfaces calculated in accordance with BS EN ISO 12241:2008
27 32
(copper pipes – oxidised) 60 11 20 15 20 18 20

Minimum insulation thickness to protect steel pipes against freezing under selected 76 12 25 16 25 20 25
28 33
industrial process conditions 89 12 25 16 25 21 25
Minimum insulation thickness required to give protection against freezing – Selected 102 12 25 17 25 21 25
29 34
commercial and institutional conditions
114 12 25 17 25 22 25
Minimum insulation thickness to protect against freezing – Selected domestic cold
30 35 140 13 25 18 25 23 25
water systems (12 hour period)

Minimum insulation thickness to protect against freezing – Selected domestic cold 169 13 25 18 25 24 25
31 36
water systems (8 hour period) 219 13 25 19 25 24 25
245 14 25 19 25 24 25
If the design/operating conditions of your particular application/scheme does not
273 14 25 19 25 24 25
correspond to those detailed in the tables, please contact ROCKWOOL Technical
Solutions for calculations to meet your specific design criteria. 324 14 25 20 25 25 25
356 14 30 20 30 25 30
406 14 30 20 30 26 30
456 14 40 20 40 26 40
508 15 40 20 40 26 40
558 15 40 21 40 26 40
610 15 40 21 40 27 40

NOTE 1
Thicknesses given are calculated specifically against the criteria noted in the table.

These thicknesses may not satisfy other design requirements. In situations where
the ambient air temperature is greater than 25ºC and/or the relative humidity
exceeds 80%, these thicknesses will not be sufficient to control condensation.

NOTE 2
These thicknesses only apply where the vapour barrier has a dark, matt finish.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 7 (BS5422:2009) Table 8 (BS5422:2009)

Minimum insulation thickness for chilled and cold water steel pipes to control Minimum insulation thickness for chilled and cold water steel pipes to control
condensation on a high emissivity outer surface (0.9) with an ambient temperature condensation on a low emissivity outer surface (0.05) with an ambient temperature
of +25°C and a relative humidity of 80% of +25°C and a relative humidity of 80%

Temperature of contents (ºC) Temperature of contents (ºC)

Outside diameter Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Outside diameter Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
of copper pipe on of steel pipe on
which insulation +10 +5 0 which insulation +10 +5 0
has been based Calculated Advised Calculated Advised Calculated Advised has been based Calculated Advised Calculated Advised Calculated Advised
(mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm)
10 7 - 10 - 12 - 17 16 20 22 25 28 30
12 8 - 10 - 13 - 21 17 20 24 25 30 30
15 8 - 11 - 14 - 27 19 20 26 30 32 35
22 9 20 12 20 15 20 33 20 20 27 30 34 35
28 9 20 13 20 16 20 42 21 25 29 30 37 40
35 10 20 13 20 17 20 48 22 25 31 35 39 40
42 10 20 14 20 17 20 60 24 25 33 35 41 45
54 11 20 14 20 18 20 76 26 30 36 40 46 50
76 12 25 16 25 20 25 89 28 30 38 40 48 50
108 12 25 17 25 21 25 102 29 30 40 40 50 50
114 30 30 41 45 52 60
NOTE 1
140 31 35 43 45 55 60
Thicknesses given are calculated specifically against the criteria noted in the table.
169 33 35 46 50 58 60
These thicknesses may not satisfy other design requirements. In situations where
the ambient air temperature is greater than 25ºC and/or the relative humidity 219 35 35 49 50 62 70
exceeds 80%, these thicknesses will not be sufficient to control condensation. 245 36 40 51 60 64 70
NOTE 2 273 37 40 52 60 66 70
These thicknesses only apply where the vapour barrier has a dark, matt finish.
324 39 40 55 55 70 70
356 40 40 56 60 71 80
406 41 45 58 60 74 80
456 43 45 60 60 76 80
508 44 45 61 70 78 80
558 45 45 63 70 80 80
610 46 50 64 70 82 90

NOTE 1
Thicknesses given are calculated specifically against the criteria noted in the table.

These thicknesses may not satisfy other design requirements. In situations where
the ambient air temperature is greater than 25ºC and/or the relative humidity
exceeds 80%, these thicknesses will not be sufficient to control condensation.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 9 (BS5422:2009) Table 10 (BS5422:2009)

Minimum insulation thickness for chilled and cold water steel pipes to control Indicative thickness of insulation for cooled and chilled water systems to control
condensation on a low emissivity outer surface (0.05) with an ambient temperature heat gain – low emissivity outer surfaces (ε = 0.05)
of +25°C and a relative humidity of 80%

Temperature of contents (ºC) Temperature of contents (ºC)

Outside diameter Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
of copper pipe on Outside diameter
which insulation +10 +5 0 of steel pipe on +10 +5 0
has been based Calculated Advised Calculated Advised Calculated Advised which insulation Calculated Calculated Heat Calculated Advised Heat Calculated Advised Heat
(mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) has been based thickness thickness gain thickness thickness gain thickness thickness gain
(mm) (mm) (mm) (W/m) (mm) (mm) (W/m) (mm) (mm) (W/m)
10 14 N/A 19 N/A 24 N/A
17.2 18 20 2.48 23 25 2.97 26 30 3.47
12 15 N/A 20 N/A 25 N/A
21.3 19 20 2.72 24 25 3.27 27 30 3.81
15 16 N/A 22 N/A 27 N/A
26.9 20 20 3.05 27 30 3.58 29 30 4.18
22 18 20 24 25 30 30
33.7 22 25 3.41 27 30 4.01 31 35 4.60
28 19 20 26 30 33 35
42.4 23 25 3.86 28 30 4.53 33 35 5.11
35 20 20 28 30 35 35
48.3 24 25 4.11 29 30 4.82 35 35 5.45
42 21 25 29 30 37 40
60.3 24 25 4.78 31 35 5.48 36 40 6.17
54 23 25 32 35 40 40
76.1 27 30 5.51 34 35 6.30 43 45 6.70
76 26 30 36 40 46 50
88.9 27 30 6.17 35 35 6.90 40 40 7.77
108 29 30 40 40 51 60
114.3 28 30 7.28 35 35 8.31 42 45 9.15

NOTE 1 139.7 29 30 8.52 36 40 9.49 43 45 10.45

Thicknesses given are calculated specifically against the criteria noted in the table. 168.3 29 30 9.89 37 40 10.97 44 45 11.86
These thicknesses may not satisfy other design requirements. In situations where 219.1 29 30 12.27 37 40 13.57 45 45 14.61
the ambient air temperature is greater than 25ºC and/or the relative humidity
exceeds 80%, these thicknesses will not be sufficient to control condensation. 273.0 30 30 14.74 37 40 16.28 45 45 17.48

NOTE 1
Insulation thicknesses in this table have been calculated according to BS EN ISO
12241:2008 using standardised assumptions: horizontal pipe in still air at 25ºC,
emissivity of outer surface of insulated system as specified.

NOTE 2
Thicknesses derived solely against the criteria noted in this table may not
necessarily satisfy other design requirements such as control of condensation.

NOTE 3
Heat gain relates to the specified thickness and temperature.

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 11 (BS5422:2009) Table 12 (BS5422:2009)

Indicative thickness of insulation for cooled and chilled water systems to control Minimum insulation thickness for condensation control on ductwork carrying chilled
heat gain – high emissivity outer surfaces (ε = 0.9) air in ambient conditions: indoor still air temperature +25°C, relative humidity 80%,
dewpoint temperature 21.3°C

Temperature of contents (ºC)

Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
Table 12 – Ductwrap
Outside diameter
of steel pipe on +10 +5 0 External surface emissivity
which insulation Calculated Calculated Heat Calculated Advised Heat Calculated Advised Heat Minimum thickness of ROCKWOOL Ductwrap (mm)
has been based thickness thickness gain thickness thickness gain thickness thickness gain 0.05 (eg bright aluminium foil) 0.44 (eg dusty galvanised steel) 0.90 (eg black paint)
Minimum
(mm) (mm) (mm) (W/m) (mm) (mm) (W/m) (mm) (mm) (W/m)
temperature inside Calculated Advised Calculated Advised Calculated Advised
17.2 18 20 2.48 23 25 2.97 26 30 3.47 duct (ºC) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm)
21.3 19 20 2.72 24 25 3.27 27 30 3.81 15 26 30 13 25 9 25
26.9 20 20 3.05 27 30 3.58 29 30 4.18 10 45 50 23 25 15 25
33.7 22 25 3.41 27 30 4.01 31 35 4.60 5 64 70 33 40 21 25
42.4 23 25 3.86 28 30 4.53 33 35 5.11 0 83 90 42 50 27 30
48.3 24 25 4.11 29 30 4.82 35 35 5.45
60.3 24 25 4.78 31 35 5.48 36 40 6.17
76.1 27 30 5.51 34 35 6.30 43 45 6.70 Table 12 – Ductslab
88.9 27 30 6.17 35 35 6.90 40 40 7.77 External surface emissivity
114.3 28 30 7.28 35 35 8.31 42 45 9.15 Minimum thickness of ROCKWOOL Ductslab (mm)

Minimum 0.05 (eg bright aluminium foil) 0.44 (eg dusty galvanised steel) 0.90 (eg black paint)
139.7 29 30 8.52 36 40 9.49 43 45 10.45
temperature inside Calculated Advised Calculated Advised Calculated Advised
168.3 29 30 9.89 37 40 10.97 44 45 11.86 duct (ºC) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm)
219.1 29 30 12.27 37 40 13.57 45 45 14.61 15 26 30 14 25 9 25
273.0 30 30 14.74 37 40 16.28 45 45 17.48 10 47 50 24 25 15 25
5 67 70 34 40 22 25
NOTE 1
0 86 90 44 50 28 30
Insulation thicknesses in this table have been calculated according to BS EN ISO
12241:2008 using standardised assumptions: horizontal pipe in still air at 25ºC,
emissivity of outer surface of insulated system as specified. NOTE 1
Thicknesses given are calculated in accordance with BS EN ISO 12241:2008 based
NOTE 2 on 0.6m vertical flat surface of rectangular duct but are also adequate for horizontal
Thicknesses derived solely against the criteria noted in this table may not surfaces.
necessarily satisfy other design requirements such as control of condensation.
NOTE 2
NOTE 3 Thicknesses given are calculated specifically against the criteria noted in the table
Heat gain relates to the specified thickness and temperature. These thicknesses may not satisfy other design requirements.

NOTE 3
Refer to Annex B, Table B. 1 for surface emissivities of common finishing materials.
In situations where the ambient air temperature is greater than 25ºC and/or the
relative humidity exceeds 80%, these thicknesses will not be sufficient to control
condensation.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 13 (BS5422:2009) Table 14 (BS5422:2009)

Indicative thickness of insulation for ductwork carrying warm air to control heat loss. Indicative thickness of insulation for chilled and dual-purpose ducting to control
heat transfer.

Table 13 – Ductwrap
Table 14 – Ductwrap
External surface emissivity External surface emissivity
Minimum thickness of ROCKWOOL Ductwrap (mm) Minimum thickness of ROCKWOOL Ductwrap (mm)
0.05 (eg bright aluminium foil) 0.44 (eg dusty galvanised steel) 0.90 (eg black paint) 0.05 (eg bright aluminium foil) 0.44 (eg dusty galvanised steel) 0.90 (eg black paint)
Max Heat Loss Calculated Advised Calculated Advised Calculated Advised Max Heat Loss Calculated Advised Calculated Advised Calculated Advised
(W/m²) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) (W/m²) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm)
16.34 31 40 37 40 39 40 6.45 50 50 58 60 61 70

Table 13 – Ductslab Table 14 – Ductslab

External surface emissivity External surface emissivity
Minimum thickness of ROCKWOOL Ductslab (mm) Minimum thickness of ROCKWOOL Ductslab (mm)
0.05 (eg bright aluminium foil) 0.44 (eg dusty galvanised steel) 0.90 (eg black paint) 0.05 (eg bright aluminium foil) 0.44 (eg dusty galvanised steel) 0.90 (eg black paint)
Max Heat Loss Calculated Advised Calculated Advised Calculated Advised Max Heat Loss Calculated Advised Calculated Advised Calculated Advised
(W/m²) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) (W/m²) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm) thickness (mm)
16.34 32 40 38 40 41 50 6.45 52 60 59 60 63 70

NOTE 1 NOTE 1
Heat loss relates to the specified thickness and temperature. Heat loss relates to the specified thickness and temperature.

NOTE 2 NOTE 2
Insulation thicknesses in this table have been calculated according to BS EN ISO Insulation thicknesses in this table have been calculated according to BS EN ISO
12241:2008 using standardised assumptions: horizontal duct at 35°C, with 600 mm 12241:2008 using standardised assumptions: horizontal duct at 13ºC, with 600 mm
vertical sidewall in still air at 15°C, emissivity of outer surface of insulated system as vertical sidewall in still air at 25ºC, emissivity of outer surface of insulated system as
specified. specified.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 15 (BS5422:2009) Table 16 (BS5422:2009)

Indicative thickness of insulation for non-domestic heating services to control heat Indicative thickness of insulation for non-domestic heating services to control heat
loss – low emissivity outer surfaces (ε =0.05) loss – high emissivity outer surfaces (ε =0.9)

Hot face temperature (ºC) Hot face temperature (ºC)

Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
Outside diameter Outside diameter
of steel pipe on 75 100 125 of steel pipe on 75 100 125
which insulation Calculated Calculated Heat Calculated Advised Heat Calculated Advised Heat which insulation Calculated Calculated Heat Calculated Advised Heat Calculated Advised Heat
has been based thickness thickness loss thickness thickness loss thickness thickness loss has been based thickness thickness loss thickness thickness loss thickness thickness loss
(mm) (mm) (mm) (W/m) (mm) (mm) (W/m) (mm) (mm) (W/m) (mm) (mm) (mm) (W/m) (mm) (mm) (W/m) (mm) (mm) (W/m)
17.2 24 25 8.90 24 25 13.34 24 25 17.92 17.2 28 30 8.90 28 30 13.34 28 30 17.92
21.3 28 30 9.28 30 30 13.56 30 30 18.32 21.3 33 35 9.28 33 35 13.56 33 35 18.32
26.9 31 35 10.06 37 40 13.83 37 40 18.70 26.9 36 40 10.06 41 45 13.83 41 45 18.70
33.7 33 35 11.07 44 45 14.39 46 50 19.02 33.7 38 40 11.07 49 50 14.39 55 60 19.02
42.4 35 35 12.30 48 50 15.66 64 70 19.25 42.4 40 40 12.30 57 60 15.66 69 70 19.25
48.3 37 40 12.94 49 50 16.67 67 70 20.17 48.3 42 45 12.94 58 60 16.67 72 80 20.17
60.3 39 40 14.45 57 60 18.25 71 70 21.96 60.3 44 45 14.45 62 70 18.25 77 80 21.96
76.1 44 45 16.35 60 60 20.42 76 80 24.21 76.1 49 50 16.35 65 70 20.42 82 90 24.21
88.9 45 45 17.91 62 70 22.09 79 80 25.99 88.9 50 50 17.91 67 70 22.09 84 90 25.99
114.3 47 50 20.77 65 70 25.31 85 90 29.32 114.3 53 60 20.77 71 80 25.31 91 100 29.32
139.7 48 50 23.71 68 70 28.23 89 90 32.47 139.7 54 60 23.71 74 80 28.23 95 100 32.47
168.3 49 50 26.89 70 70 31.61 92 100 36.04 168.3 55 60 26.89 76 80 31.61 98 100 36.04
219.1 50 50 32.54 72 80 37.66 96 100 42.16 219.1 56 60 32.54 79 80 37.66 102 120 42.16
273.0 50 50 38.83 74 80 43.72 99 100 48.48 273.0 57 60 38.83 81 90 43.72 106 120 48.48

NOTE 1 NOTE 1
Insulation thicknesses in this table have been calculated according to Insulation thicknesses in this table have been calculated according to
BS EN ISO 12241:2008 using standardised assumptions: horizontal pipe in still air at BS EN ISO 12241:2008 using standardised assumptions: horizontal pipe in still air at
15°C, emissivity of outer surface of insulated system as specified. 15°C, emissivity of outer surface of insulated system as specified.

NOTE 2 NOTE 2
Heat loss relates to the specified thickness and temperature. Heat loss relates to the specified thickness and temperature.

NOTE 3 NOTE 3
The thicknesses in this table are applicable to pipes serving commercial solar hot The thicknesses in this table are applicable to pipes serving commercial solar hot
water panels. water panels.

ROCKWOOL Ltd ROCKWOOL Ltd

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Table 17 (BS5422:2009) Table 18 (BS5422:2009)

Indicative thickness of insulation for non-domestic hot water service areas to control Indicative thickness of insulation for non-domestic hot water service areas to control
heat loss – low emissivity outer surfaces heat loss – high emissivity outer surfaces

Outside diameter of steel Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Outside diameter of steel Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
pipe on which insulation pipe on which insulation
thickness has been based thickness has been based
(mm) Calculated thickness (mm) Advised thickness (mm) Heat loss (W/m) (mm) Calculated thickness (mm) Advised thickness (mm) Heat loss (W/m)
17.2 23 25 6.60 17.2 27 30 6.60
21.3 25 25 7.13 21.3 29 30 7.13
26.9 27 30 7.83 26.9 32 35 7.83
33.7 29 30 8.62 33.7 33 35 8.62
42.4 30 30 9.72 42.4 35 35 9.72
48.3 32 35 10.21 48.3 37 40 10.21
60.3 33 35 11.57 60.3 35 35 11.57
76.1 35 35 13.09 76.1 43 45 13.09
88.9 35 35 14.58 88.9 43 45 14.58
114.3 38 40 17.20 114.3 44 45 17.20
139.7 39 40 19.65 139.7 45 45 19.65
168.3 40 40 22.31 168.3 46 50 22.31
219.1 40 40 27.52 219.1 47 50 27.52
273.0 41 45 32.40 273.0 48 50 32.40

NOTE 1 NOTE 1
Insulation thicknesses in this table have been calculated according to Insulation thicknesses in this table have been calculated according to
BS EN ISO 12241:2008 using standardised assumptions: horizontal pipe at 60°C in BS EN ISO 12241:2008 using standardised assumptions: horizontal pipe at 60°C in
still air at 15°C, emissivity of outer surface of insulated system as specified. still air at 15°C, emissivity of outer surface of insulated system as specified.

NOTE 2 NOTE 2
Heat loss relates to the specified thickness and temperature. Heat loss relates to the specified thickness and temperature.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 19 (BS5422:2009) Table 20 (BS5422:2009)

Indicative thickness of insulation for domestic heating and hot water systems having Indicative thickness of insulation for domestic heating and hot water systems having
low emissivity outer surfaces high emissivity outer surfaces

Outside diameter of copper Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Outside diameter of copper Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
pipe on which insulation pipe on which insulation
thickness has been based thickness has been based
(mm) Calculated thickness (mm) Advised thickness (mm) Heat loss (W/m) (mm) Calculated thickness (mm) Advised thickness (mm) Heat loss (W/m)
8.0 - - 7.06 8.0 - - 7.06
10.0 - - 7.23 10.0 - - 7.23
12.0 - - 7.35 12.0 - - 7.35
15.0 - - 7.89 15.0 - - 7.89
22.0 15 20 9.12 22.0 19 20 9.12
28.0 17 20 10.07 28.0 21 25 10.07
35.0 18 20 11.08 35.0 22 25 11.08
42.0 19 20 12.19 42.0 24 25 12.19
54.0 20 20 14.12 54.0 25 25 14.12

NOTE 1 NOTE 1
Insulation thicknesses in this table have been calculated according to Insulation thicknesses in this table have been calculated according to
BS EN ISO 12241:2008 using standardised assumptions: horizontal pipe at 60°C in BS EN ISO 12241:2008 using standardised assumptions: horizontal pipe at 60°C in
still air at 15°C, emissivity of outer surface of insulated system as specified. still air at 15°C, emissivity of outer surface of insulated system as specified.

NOTE 2 NOTE 2
Heat loss relates to the specified thickness and temperature. Heat loss relates to the specified thickness and temperature.

NOTE 3 NOTE 3
This table is applicable to pipes serving solar hot water panels. This table is applicable to pipes serving solar hot water panels.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 22 (BS5422:2009) Table 23 (BS5422:2009)

Minimum insulation thickness to control the surface temperature of a non-metallic Minimum insulation thickness to control the surface temperature of a metallic
surface with a surface emissivity of 0.90 and design cold face temperature of 59°C surface with a surface emissivity of 0.05 and design cold face temperature of 50°C

Hot face temperature (ºC) Hot face temperature (ºC)

Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
Outside diameter Outside diameter
of steel pipe on 100 150 200 250 of steel pipe on 100 150 200 250
which insulation Calculated Calculated Calculated Advised Calculated Advised Calculated Advised which insulation Calculated Calculated Calculated Advised Calculated Advised Calculated Advised
has been based thickness thickness thickness thickness thickness thickness thickness thickness has been based thickness thickness thickness thickness thickness thickness thickness thickness
(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)
17 3 20 6 20 10 20 13 20 17 7 20 14 20 22 25 31 35
21 3 20 7 20 10 20 14 20 21 8 20 15 20 24 25 33 35
27 3 20 7 20 11 20 15 20 27 8 20 17 20 26 30 36 40
33 3 20 7 20 11 20 16 20 33 9 20 18 20 27 30 38 40
42 4 20 8 20 12 20 17 20 42 10 20 19 20 29 30 41 45
48 4 20 8 20 12 20 17 20 48 10 20 20 20 31 35 43 45
60 4 20 8 20 13 20 18 20 60 10 20 21 25 33 35 46 50
76 4 25 9 25 14 25 20 25 76 12 25 24 25 37 40 52 50
89 4 25 9 25 15 25 21 25 89 12 25 25 25 39 40 55 60
102 4 25 9 25 15 25 21 25 102 13 25 26 30 41 45 57 60
114 4 25 9 25 15 25 22 25 114 13 25 27 30 42 45 59 60
140 4 25 10 25 16 25 23 25 140 14 25 28 30 45 45 63 60
169 4 25 10 25 16 25 23 25 169 14 25 30 30 47 50 67 70
219 5 25 10 25 17 25 24 25 219 15 25 32 35 51 60 72 80
245 5 25 10 25 17 25 25 25 245 16 25 33 35 52 60 74 80
273 5 25 11 25 17 25 25 25 273 16 25 34 35 54 60 77 80
324 5 25 11 25 18 25 26 25 324 17 25 35 35 56 60 80 80
356 5 30 11 30 18 30 26 30 356 17 30 36 40 58 60 83 90
406 5 30 11 30 18 30 27 30 406 18 30 37 40 60 60 86 90
456 5 40 11 40 19 40 27 40 456 18 40 39 40 62 70 88 90
508 5 40 11 40 19 40 27 40 508 19 40 40 40 64 70 91 100
558 5 40 11 40 19 40 28 40 558 19 40 41 45 65 70 91 100
610 5 40 12 40 19 40 28 40 610 19 40 41 45 65 70 91 100
flat 5 40 12 40 18 40 27 40 flat 19 40 41 50 62 70 82 90

NOTE 1 NOTE 4 NOTE 1 NOTE 4

Insulation thicknesses in this table have been calculated according to The thermal conductivity of insulation materials increases with mean Insulation thicknesses in this table have been calculated according to The thermal conductivity of insulation materials increases with mean
BS EN ISO 12241:2008 using standardised assumptions: horizontal temperature and for any given material. The use of a different thermal BS EN ISO 12241:2008 using standardised assumptions: horizontal temperature and for any given material. The use of a different thermal
pipe in still air at 20°C. Surface emissivity corresponding to outer conductivity can be required for each operating temperature. pipe in still air at 20°C. Surface emissivity corresponding to outer conductivity can be required for each operating temperature.
surface specified. surface specified.
NOTE 5 NOTE 5
NOTE 2 These thicknesses may not satisfy other design requirements, in NOTE 2 These thicknesses may not satisfy other design requirements, in
Maximum heat loss values for intermediate operating temperatures particular those for control of surface temperature (see Table 22, Maximum heat loss values for intermediate operating temperatures particular those for control of surface temperature (see Table 22,
may be deduced by interpolation. Table 23 and Table 24). may be deduced by interpolation. Table 23 and Table 24).

NOTE 3 NOTE 6 NOTE 3 NOTE 6

Heat loss measured in Watts per metre (W/m) relates to the specified To simplify the use of this table the values shaded have been Heat loss measured in Watts per metre (W/m) relates to the specified To simplify the use of this table the values shaded have been
thickness and temperature. adjusted to avoid the specification of apparently anomalous results thickness and temperature. adjusted to avoid the specification of apparently anomalous results
given by the calculation method in BS EN ISO 12241, due to the given by the calculation method in BS EN ISO 12241, due to the
transition from turbulent to laminar flow. transition from turbulent to laminar flow.

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 24 (BS5422:2009) Table 24 (BS5422:2009)

Minimum insulation thickness to control the surface temperature of a non-metallic Minimum insulation thickness to control the surface temperature of a metallic
surface with a surface emissivity of 0.90 and design cold face temperature of 50°C surface with a surface emissivity of 0.05 and design cold face temperature of 55ºC

Hot face temperature (ºC) Hot face temperature (ºC)

Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
Outside diameter Outside diameter
of steel pipe on 100 150 200 250 of steel pipe on 100 150 200 250
which insulation Calculated Calculated Calculated Advised Calculated Advised Calculated Advised which insulation Calculated Calculated Calculated Advised Calculated Advised Calculated Advised
has been based thickness thickness thickness thickness thickness thickness thickness thickness has been based thickness thickness thickness thickness thickness thickness thickness thickness
(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)
17 5 20 9 20 13 20 18 20 17 6 20 12 20 18 20 26 30
21 5 20 9 20 14 20 19 20 21 6 20 13 20 20 20 27 30
27 5 20 10 20 15 20 20 20 27 7 20 14 20 21 25 30 30
33 5 20 10 20 15 20 21 25 33 7 20 14 20 23 25 32 35
42 5 20 11 20 16 20 22 25 42 7 20 15 20 24 25 34 35
48 6 20 11 20 17 20 23 25 48 8 20 16 20 25 25 35 35
60 6 20 11 20 18 20 24 25 60 8 20 17 20 27 30 38 40
76 6 25 13 25 19 25 27 30 76 9 20 19 25 31 35 43 45
89 6 25 13 25 20 25 28 30 89 9 20 20 25 32 35 46 50
102 7 25 13 25 21 25 29 30 102 10 20 21 25 33 35 48 50
114 6 25 13 25 21 25 30 30 114 10 25 21 25 34 35 49 50
140 7 25 13 25 22 25 31 30 140 10 25 23 25 37 35 52 60
169 7 25 14 25 23 25 32 30 169 11 25 24 25 39 40 55 60
219 7 25 15 25 23 25 33 35 219 12 25 26 30 41 45 59 60
245 7 25 15 25 24 25 34 35 245 12 25 26 30 43 45 61 70
273 7 25 15 25 24 25 35 35 273 12 25 27 30 44 45 63 70
324 8 25 16 25 25 25 35 35 324 13 25 28 30 46 50 66 70
356 8 30 16 30 25 30 36 40 356 13 30 29 30 47 50 68 70
406 8 30 16 30 26 30 37 40 406 13 30 30 30 49 50 71 80
456 8 40 16 40 26 40 37 40 456 14 40 31 40 50 50 73 80
508 8 40 16 40 26 40 38 40 508 14 40 32 40 52 60 75 80
558 8 40 17 40 27 40 38 40 558 14 40 32 40 52 60 75 80
610 8 40 17 40 27 40 39 40 610 15 40 32 40 52 60 75 80
flat 8 40 17 40 27 40 39 40 flat 15 40 32 40 52 60 75 80

NOTE 1 NOTE 4
Insulation thicknesses in this table have been calculated according to The thermal conductivity of insulation materials increases with mean NOTE 1
BS EN ISO 12241:2008 using standardised assumptions: horizontal temperature and for any given material. The use of a different thermal Thicknesses given are calculated specifically against the criteria noted in the table,
pipe in still air at 20°C. Surface emissivity corresponding to outer conductivity can be required for each operating temperature. Adopting these thicknesses may not necessarily satisfy other design requirements.
surface specified.
NOTE 5 NOTE 2
NOTE 2 These thicknesses may not satisfy other design requirements, in To simplify the use of this table the values shaded have been adjusted to avoid the
Maximum heat loss values for intermediate operating temperatures particular those for control of surface temperature (see Table 22, specification of apparently anomalous results given by the calculation method in
may be deduced by interpolation. Table 23 and Table 24). BS EN ISO 12241, due to the transition from turbulent to laminar flow.
NOTE 3 NOTE 6
Heat loss measured in Watts per metre (W/m) relates to the specified To simplify the use of this table the values shaded have been
thickness and temperature. adjusted to avoid the specification of apparently anomalous results
given by the calculation method in BS EN ISO 12241, due to the
transition from turbulent to laminar flow.

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 24 (BS5422:2009) Table 24 (BS5422:2009)

Minimum insulation thickness to control the surface temperature of a metallic Minimum insulation thickness to control the surface temperature of a metallic
surface with a surface emissivity of 0.18 and design cold face temperature of 55°C surface with a surface emissivity of 0.26 and design cold face temperature of 55°C

Hot face temperature (ºC) Hot face temperature (ºC)

Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm) Thickness of ROCKWOOL Rocklap H&V Pipe Section (mm)
Outside diameter Outside diameter
of steel pipe on 100 150 200 250 of steel pipe on 100 150 200 250
which insulation Calculated Calculated Calculated Advised Calculated Advised Calculated Advised which insulation Calculated Calculated Calculated Advised Calculated Advised Calculated Advised
has been based thickness thickness thickness thickness thickness thickness thickness thickness has been based thickness thickness thickness thickness thickness thickness thickness thickness
(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)
17 5 20 11 20 16 20 23 25 17 5 20 10 20 16 20 22 25
21 6 20 11 20 18 20 24 25 21 5 20 11 20 17 20 23 25
27 6 20 12 20 19 20 26 30 27 6 20 11 20 18 20 25 25
33 6 20 13 20 20 20 28 30 33 6 20 12 20 19 20 26 30
42 7 20 14 20 21 25 30 30 42 6 20 13 20 20 20 28 30
48 7 20 14 20 22 25 31 35 48 6 20 13 20 21 25 29 30
60 7 20 15 20 24 25 33 35 60 7 20 14 20 22 25 31 35
76 8 25 16 25 27 30 38 40 76 7 25 16 25 25 25 35 35
89 8 25 18 25 28 30 39 40 89 8 25 16 25 26 30 37 40
102 8 25 18 25 29 30 41 45 102 8 25 17 25 27 30 38 40
114 9 25 19 25 30 30 42 45 114 8 25 17 25 28 30 39 40
140 9 25 20 25 31 35 45 45 140 8 25 18 25 29 30 41 45
169 9 25 20 25 33 35 47 45 169 9 25 19 25 30 30 43 45
219 10 25 22 25 35 35 50 50 219 9 25 20 25 32 35 46 50
245 10 25 22 25 36 40 52 60 245 9 25 20 25 33 35 47 50
273 10 25 23 25 37 40 53 60 273 9 25 21 25 34 35 48 50
324 11 25 24 25 38 40 55 60 324 10 25 21 25 35 35 50 50
356 11 30 24 30 39 40 57 60 356 10 30 22 30 36 40 51 60
406 11 30 25 30 40 40 58 60 406 10 30 22 30 37 40 53 60
456 11 40 25 40 41 45 60 60 456 10 40 23 40 37 40 54 60
508 12 40 26 40 42 45 61 70 508 11 40 23 40 38 40 55 60
558 12 40 26 40 43 45 61 70 558 11 40 24 40 39 40 55 60
610 12 40 26 40 43 45 61 70 610 11 40 24 40 39 40 55 60
flat 12 40 26 40 43 50 61 70 flat 11 40 24 40 39 40 55 60

NOTE 1 NOTE 1
Thicknesses given are calculated specifically against the criteria noted in the table, Thicknesses given are calculated specifically against the criteria noted in the table,
Adopting these thicknesses may not necessarily satisfy other design requirements. Adopting these thicknesses may not necessarily satisfy other design requirements.

NOTE 2 NOTE 2
To simplify the use of this table the values shaded have been adjusted to avoid the To simplify the use of this table the values shaded have been adjusted to avoid the
specification of apparently anomalous results given by the calculation method in specification of apparently anomalous results given by the calculation method in BS
BS EN ISO 12241, due to the transition from turbulent to laminar flow. EN ISO 12241, due to the transition from turbulent to laminar flow.

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 25 (BS5422:2009) Table 26 (BS5422:2009)

Heat loss from bare surfaces calculated in accordance with BS EN ISO 12241:2008 Heat loss from bare surfaces calculated in accordance with BS EN ISO 12241:2008
(black steel pipes) (copper pipes – commercial grade, scoured to a shine)

Operating temperature (ºC) Operating temperature (ºC)

Outside diameter 50 100 150 200 250 Outside diameter of 50 100 150 200
of steel pipe (mm) Heat loss (W/m pipes, W/m² flat) copper pipe (mm) Heat loss (W/m pipes, W/m² flat)
12.0 17 57 110 176 257 12.0 11 36 66 100
15.0 20 69 133 214 313 15.0 12 43 79 119
17.2 23 78 150 241 353 17.2 14 47 87 132
21.3 27 93 180 290 427 21.3 16 56 103 156
22.0 28 96 186 299 439 22.0 17 57 105 160
26.9 33 114 221 356 525 26.9 19 66 123 186
28.0 35 118 229 369 544 28.0 20 69 127 192
33.7 41 139 269 435 641 33.7 23 79 146 222
42.0 49 168 326 528 781 42.0 27 93 173 263
42.4 50 169 329 532 788 42.4 28 94 174 265
48.3 56 190 369 598 885 48.3 31 104 192 292
54.0 61 209 407 660 979 54.0 33 113 210 319
60.3 68 230 448 728 1081 60.3 36 123 228 347
67.0 74 253 492 800 1188 67.0 39 134 248 377
76.1 83 283 551 896 1333 76.1 43 148 273 416
80.0 87 295 576 938 1395 80.0 45 153 284 432
88.9 95 324 632 1031 1535 88.9 49 166 308 469
101.6 107 365 712 1162 1733 101.6 54 184 341 520
108.0 113 385 752 1228 1832 108.0 57 193 358 545
114.3 119 405 791 1292 1929 114.3 59 202 374 570
139.7 142 484 947 1549 2316 139.7 69 236 437 666
168.3 167 571 1119 1833 2746 168.3 80 272 505 770
219.1 212 722 1419 2330 3498 219.1 98 334 619 946
273.0 258 880 1731 2848 4283 273.0 116 396 735 1123
323.9 301 1027 2021 3331 5016 323.9 133 452 840 1284
flat 119 647 1244 1938

Operating conditions: Operating conditions:

Ambient still air: 20ºC Ambient still air: 20ºC

Surface emissivity: 0.07 Surface emissivity: 0.07

Height of flat surfaces: 0.6m Height of flat surfaces: 0.6m

Surface orientation: horizontal Surface orientation: horizontal

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 27 (BS5422:2009) Table 28 (BS5422:2009)

Heat loss from bare surfaces calculated in accordance with BS EN ISO 12241:2008 Minimum insulation thickness to protect steel pipes against freezing under selected
(copper pipes – oxidised) industrial process conditions

Operating temperature (ºC) Initial temperature: +5ºC Minimum Initial temperature: +5ºC Minimum
ambient air temperature: -10ºC ambient air temperature: -10ºC
Outside diameter of 50 100 150 200 Evaluation period: 12 hours Permitted Evaluation period: 12 hours Permitted
copper pipe (mm) Heat loss (W/m pipes, W/m² flat) ice formation nil ice formation 10%
12.0 15 52 99 158 Thickness of ROCKWOOL RockLap H&V Pipe Section (mm)
15.0 18 63 120 191
Outside diameter Inside diameter of Calculated thickness Advised thickness Calculated thickness Advised thickness
17.2 21 70 135 215 of steel pipe (mm) pipe (bore) (mm) (mm) (mm) (mm) (mm)
21.3 25 84 162 258 21.3 16.0 - - - -
22.0 25 87 166 265 26.9 21.6 - - - -
26.9 30 103 197 315 33.7 27.2 - - 251 -
28.0 31 106 204 326 42.4 35.9 - - 89 90
33.7 36 124 239 383 48.3 41.8 452 - 59 60
42.0 44 150 289 464 60.3 53.0 173 - 34 35
42.4 44 151 292 468 76.1 68.8 87 90 23 25
48.3 50 169 326 524 88.9 80.8 62 70 19 20
54.0 55 186 359 578 114.3 105.3 40 40 13 25
60.3 60 205 395 636 168.3 158.6 23 25 9 25
67.0 66 224 433 698 219.1 207.9 17 25 6 25
76.1 73 250 484 781
80.0 77 261 505 816 NOTE 1
88.9 84 286 554 895 Thicknesses given are calculated specifically against the criteria noted in the table
These thicknesses may not satisfy other design requirements.
101.6 94 321 623 1007
NOTE 2
108.0 99 339 657 1063 Some of the insulation thicknesses given are too large to be applied in practice but
114.3 104 356 691 1118 a selection is included to highlight the difficulty in protecting small diameter pipes
against freezing. To provide the appropriate degree of frost protection to certain
139.7 124 424 824 1336 sizes of pipes, it may be necessary to provide additional heat to the system, for
168.3 146 499 971 1577 example by circulating the water or heat tracing.

219.1 184 629 1226 1997 NOTE 3

Assumed densities (ƿ) and heat capacities (cp) are as follows:
273.0 224 763 1491 2432
• ƿ water = 1,000 kg/m³, cp water = 4,200 J/kg.K;
323.9 261 888 1737 2837
flat 245 1076 2125 3464 • ƿ steel = 7,840 kg/m³, cp steel = 455 J/kg.K

Operating conditions:

Ambient still air: 20ºC

Surface emissivity: 0.70

Height of flat surfaces: 0.6m

Surface orientation: horizontal

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 29 (BS5422:2009) Table 30 (BS5422:2009)

Minimum insulation thickness required to give protection against freezing under Minimum insulation thickness to protect against freezing for domestic cold water
specified commercial and institutional conditions systems [12 h]

Initial temperature: +2ºC Minimum Initial temperature: +2ºC Minimum Normal installation inside the building Extreme installation - inside the
ambient air temperature: -6ºC (indoor ambient air temperature: -10ºC inside the envelope of the insulation building but outside the envelope of
unheated) Evaluation period: 12 hours (outdoor) Evaluation period: 12 hours Initial temperature +7ºC Minimum the insulation Initial temperature +2ºC
Permitted ice formation 50% Permitted ice formation 50% ambient air temperature -6ºC Minimum ambient air temperature -6ºC
Outside diameter Inside diameter of Evaluation period 12 hours Permitted Evaluation period 12 hours Permitted
Thickness of ROCKWOOL RockLap H&V Pipe Section (mm) ice formation 50% ice formation 50%
of pipe (mm) pipe (bore) (mm)
Calculated thickness Advised thickness Calculated thickness Advised thickness Outside diameter Inside diameter of
Thickness of ROCKWOOL RockLap H&V Pipe Section (mm)
Copper pipes (mm) (mm) (mm) (mm) of pipe (mm) pipe (bore) (mm)
Calculated thickness Advised thickness Calculated thickness Advised thickness
15.0 13.6 66 - 315 - Copper pipes (mm) (mm) (mm) (mm)
22.0 20.2 19 20 47 50
15.0 13.6 49 - 66 -
28.0 26.2 12 20 24 25
22.0 20.2 17 20 19 20
35.0 32.6 9 20 16 20
28.0 26.2 11 20 12 25
42.0 39.6 7 20 12 20
35.0 32.6 8 20 9 20
54.0 51.6 5 20 8 20
42.0 39.6 6 20 7 20
76.1 73.1 4 25 6 25
54.0 51.6 5 20 5 20
108.0 105.0 3 25 4 25
76.1 73.1 3 25 4 25
Calculated thickness Advised thickness Calculated thickness Advised thickness
Steel pipes (mm) (mm) (mm) (mm)
108.0 105.0 2 25 3 25
Calculated thickness Advised thickness Calculated thickness Advised thickness
21.3 16.0 40 40 142 - Steel pipes (mm) (mm) (mm) (mm)
26.9 21.6 19 20 43 45
21.3 16.0 32 40 40 40
33.7 27.2 13 20 25 25
26.9 21.6 16 20 19 20
42.4 35.9 8 20 15 20
33.7 27.2 11 20 13 20
48.3 41.8 7 20 12 20
42.4 35.9 7 20 8 20
60.3 53.0 5 20 9 20
48.3 41.8 6 20 7 20
76.1 68.8 4 25 6 25
60.3 53.0 5 20 5 20
88.9 80.0 3 25 5 25
76.1 68.8 4 25 4 20
88.9 80.0 3 25 3 25
NOTE 1
Thicknesses given are calculated specifically against the criteria noted in the table
These thicknesses may not satisfy other design requirements. NOTE 1
Thicknesses given are calculated specifically against the criteria noted in the table
NOTE 2 These thicknesses may not satisfy other design requirements.
Some of the insulation thicknesses given are too large to be applied in practice but
a selection is included to highlight the difficulty in protecting small diameter pipes NOTE 2
against freezing. To provide the appropriate degree of frost protection to certain Some of the insulation thicknesses given are too large to be applied in practice but
sizes of pipes, it may be necessary to provide additional heat to the system, for a selection is included to highlight the difficulty in protecting small diameter pipes
example by circulating the water or heat tracing. against freezing. To provide the appropriate degree of frost protection to certain
sizes of pipes, it may be necessary to provide additional heat to the system, for
NOTE 3 example by circulating the water or heat tracing.
Assumed densities (ƿ) and heat capacities (cp) are as follows:
NOTE 3
• ƿ water = 1,000 kg/m³, cp water = 4,200 J/kg.K; Assumed densities (ƿ) and heat capacities (cp) are as follows:
• ƿ steel = 7,840 kg/m³, cp steel = 455 J/kg.K • ƿ water = 1,000 kg/m³, cp water = 4,200 J/kg.K;

• ƿ steel = 7,840 kg/m³, cp steel = 455 J/kg.K

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Table 31 (BS5422:2009) HVAC products available from ROCKWOOL

Minimum insulation thickness to protect against freezing for domestic cold water
systems [8 h]

Normal installation inside the building Extreme installation - inside the

inside the envelope of the insulation building but outside the envelope of
Initial temperature +7ºC Minimum the insulation Initial temperature +2ºC
ambient air temperature -6ºC Minimum ambient air temperature -6ºC
Evaluation period 8 hours Permitted ice Evaluation period 8 hours Permitted ice
formation 50% formation 50%
Outside diameter Inside diameter of
Thickness of ROCKWOOL RockLap H&V Pipe Section (mm)
of pipe (mm) pipe (bore) (mm)
Calculated thickness Advised thickness Calculated thickness Advised thickness
Copper pipes (mm) (mm) (mm) (mm) RockLap H&V Pipe Sections Ductwrap and Ductslab Fire Duct Systems
15.0 13.6 22 not available 26 not available (previously Conlit® Ductwork Systems)
For rapid, efficient pipework insulation. For the thermal insulation of ductwork
22.0 20.2 10 20 11 20 RockLap H&V Pipe Sections are strong and water storage tanks. ROCKWOOL Single layer fire protection for
lengths of pre-formed insulation with Ductwrap and Ductslab provide thermal rectangular, circular and oval ducts. As
28.0 26.2 7 20 7 20
a one piece, factory applied foil facing insulation for air conditioning, warm air part of the comprehensive ROCKWOOL
35.0 32.6 5 20 6 20 with integral self-adhesive lap. The and extract ducts used in the internal FIREPRO® range of fire protection
integral lap ensures fast and easy and external environment generally products, Fire Duct Systems (previously
42.0 39.6 4 20 4 20 installation: just snap the Sections onto within plant rooms and boiler houses. Conlit® Ductwork Systems) provide fire
54.0 51.6 3 20 3 20 the pipe, peel off the backing tape and protection and thermal and acoustic
smooth down for a completely sealed insulation for circular and rectangular
76.1 73.1 2 25 2 25 joint. steel ductwork.
108.0 105.0 2 25 2 25
Calculated thickness Advised thickness Calculated thickness Advised thickness
Steel pipes (mm) (mm) (mm) (mm)
21.3 16.0 17 20 20 20
26.9 21.6 10 20 11 20
33.7 27.2 7 20 8 20
42.4 35.9 5 20 5 20
48.3 41.8 4 20 5 20
60.3 53.0 3 20 4 20
76.1 68.8 3 25 3 25
88.9 80.0 2 25 2 25
Techwrap2 and Techtube Lamella Mat Insulated Fire Sleeves
NOTE 1 High performance acoustic solutions Lamella Mat is particularly suitable for Fire stopping for insulated pipe
Thicknesses given are calculated specifically against the criteria noted in the table for pipes and equipment. ROCKWOOL the insulation of heating and ventilation penetrations. As part of the
These thicknesses may not satisfy other design requirements. Techwrap2 and Techtube form part of a pipework and ductwork and as an comprehensive ROCKWOOL FIREPRO®
range of high performance ROCKWOOL overlay to upgrade existing insulation. range of fire protection products,
NOTE 2
acoustic insulation products. ROCKWOOL Insulated Fire Sleeves are
Some of the insulation thicknesses given are too large to be applied in practice but
a unique combination of stone wool and
a selection is included to highlight the difficulty in protecting small diameter pipes
graphite intumescent. They provide all
against freezing. To provide the appropriate degree of frost protection to certain
the ROCKWOOL thermal, noise and
sizes of pipes, it may be necessary to provide additional heat to the system, for
fire benefits with an added intumescent
example by circulating the water or heat tracing.
effect.
NOTE 3
Assumed densities (ƿ) and heat capacities (cp) are as follows:

• ƿ water = 1,000 kg/m³, cp water = 4,200 J/kg.K;

• ƿ steel = 7,840 kg/m³, cp steel = 455 J/kg.K

ROCKWOOL Ltd ROCKWOOL Ltd

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 THE THICKNESS OF ROCKWOOL INSULATION THE THICKNESS OF ROCKWOOL INSULATION

Sustainability Environment Notes

As an environmentally conscious Made from a renewable and
company, ROCKWOOL promotes plentiful naturally occuring resource,
the sustainable production and use ROCKWOOL insulation saves fuel costs
of insulation and is committed to a and energy in use and relies on trapped
continuous process of environmental air for its thermal properties.
improvement.
ROCKWOOL insulation does not
All ROCKWOOL products provide contain (and has never contained) gases
outstanding thermal protection as well that have ozone depletion potential
as four added benefits: (ODP) or global warming potential
(GWP).

ROCKWOOL is approximately 97%

Fire resistance recyclable. For waste ROCKWOOL
material that may be generated
during installation or at end of life, we
Acoustic comfort are happy to discuss the individual
requirements of contractors and users
Sustainable materials considering returning these materials to
our factory for recycling.
Durability

Health & Safety

The safety of ROCKWOOL stone wool
is confirmed by current UK and Republic
of Ireland health & safety regulations
and EU directive 97/69/EC:ROCKWOOL
fibres are not classified as a possible
human carcinogen.

A Material Safety Data Sheet is

available and can be downloaded
from www.rockwool.co.uk to assist in
the preparation of risk assessments, as
required by the Control of Substances
Hazardous to Health Regulations
(COSHH).

Interested?
For further information, contact the Technical Solutions Team on 01656 868490
or email technical.solutions@rockwool.co.uk
Visit www.rockwool.co.uk to view our complete range of products and services.
Copyright ROCKWOOL February 2018.

ROCKWOOL Ltd ROCKWOOL Ltd

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March 2018

ROCKWOOL Limited
Pencoed
Bridgend
CF35 6NY
Tel: 01656 862 621
info@rockwool.co.uk
rockwool.co.uk