01 02 Standard References

DUCTWORK SPECIFICATION

01 - General

01 – 01 Scope

All air conditioning ductwork and associated fittings shall be insulated for condensation control and energy saving.

Acoustic insulation of engineering service pipe and ductwork to prevent nuisance mechanical service noise shall also be considered.

01 – 02 Standard References

The materials, components and completed installations shall conform to applicable Standards current at the time of tendering.

Relevant standards may include:

BS 476 Fire Tests on Building Materials and Structures.

BS EN 12667 Thermal performance of building materials and products. Determination of

thermal resistance by means of guarded hot plate and heat flow meter

methods. Products of high and medium thermal resistance.

BS 3533 Glossary of terms relating to thermal insulation.

BS 5970 Thermal insulation of pipework and equipment in the temperature range of

-100°C to + 870°C

BS 5422 Method for specifying thermal insulation materials for pipes, tanks, vessels, ductwork and equipment operating within the temperature range -40°C to +700°C.

EN 13501-1 Fire classification of construction products and building elements. Classification using test data from reaction to fire tests.

01 – 03 Services to be Insulated

All air conditioning ductwork and associated fittings shall be insulated

Acoustic insulation of engineering service pipe and ductwork to prevent nuisance mechanical service noise shall also be considered.

The installation work shall be carried out by suitably trained insulation contractors who hold TICA membership.

01 – 04 Ductwork Air Leakage Testing

Shall, be conducted prior to the application of insulation. Under no circumstances shall the ductwork be pierced by insulation pins following the successful completion of an air leakage test. With the exception of self-adhesive backed insulation sheet, all insulation shall be applied only with Armaflex 520 or Armaflex RS850 adhesives.

02 – Materials

02 – 01 General

All insulation materials shall be:-

Obtained, where available from an ISO 9001:2000 “quality systems” and ISO 14001:2004 “environmental systems” certified manufacturer.

Shown to be Formaldehyde free in order not to contribute towards the maximum long term exposure limit of 2 parts per million (as recommended by the HSE).

Shown to inhibit the growth of mould.

All Armaflex materials shall be installed as to the manufacturer’s recommendations using the appropriate Armaflex adhesive:

Product / Appropriate Adhesive
AF/Armaflex Class O / Armaflex 520 Adhesive or Armaflex RS850 Adhesive
HT/Armaflex / Armaflex HT625 Adhesive
Armaflex Ultima / Armaflex Ultima 700 Adhesive or Armaflex Ultima RS850 Adhesive

Insulation installed in locations exposed to weather conditions shall be provided with a suitable weather resistant finish in the form of a covering of Armafinish 99 UV protective paint or an Armaflex product with a pre-applied PVC covering such as Armaflex Tuffcoat or Arma-Chek Silver used.

All thermal insulation shall have an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of 0 as required.

The thermal insulation must be CE marked in accordance with the relevant European standard.

All AF/Armaflex Class O shall be manufactured in the UK by Armacell UK Ltd in Oldham.

03 – Insulation

03 – 01 Selection

Shall be:-

For air conditioning ductwork

For internal ducts:

AF/Armaflex Class O elastomeric nitrile rubber with a Class O fire rating when tested under BS 476 Part 6 and BS 476 Part 7 or Armaflex Ultima with at least Euroclass B-s2,d0 fire rating according to EN 13501-1. The thickness of insulation shall be sufficient to prevent condensation under specified conditions. The material shall be CFC and H-CFC free. The material shall incorporate Microban® anti-microbial protection to actively inhibit the growth of mould.

For external ducts:

UV resistant HT/Armaflex elastomeric EPDM rubber. The thickness of insulation shall be sufficient to prevent condensation under specified conditions.

AF/Armaflex Class O elastomeric nitrile rubber painted using Armafinish 99 UV resistant paint.

Armaflex with a pre-applied PVC covering such as Armaflex Tuffcoat or Arma-Chek Silver.

03 – 02 Thermal Insulation Materials

Material / Temp Range / “K” Value W/mK at mean temp / ODP
Rating / GWP
Rating / Fire Class / Typical material density kg/m3
AF/Armaflex Class O / -50ºC to +110ºC / 0.033 @ 0ºC / 0 / 0 / Class O / To be around 50
HT/Armaflex / -196ºC to
+150ºC / 0.042 @ 40ºC / 0 / 0 / Class 1 / 65
Armaflex Ultima / -50ºC to +110ºC / 0.040 @ 0°C / 0 / 0 / B-s1,d0 / B-s2,d0 / 65
Armaflex Duct Plus / -50ºC to +110ºC / 0.036 @ 0°C / 0 / 0 / B-s3, d0 / To be around
50
Arma-Chek Silver (AF/Armaflex pre-covered with a PVC laminate) / -50ºC to +110ºC / 0.033 @ 0°C / 0 / 0 / Class O / To be around
50
Armaflex Tuffcoat (AF/Armaflex Class O pre-covered with a PVC film) / -50ºC to +110ºC / 0.033 @ 0°C / 0 / 0 / Class O / To be around
50

For temperatures down to -200°C contact the insulation manufacturer’s technical department.

04 – Protection and Protective Coverings

04 – 01 Internal Coverings

Shall be:

For AF/Armaflex Class O elastomeric nitrile rubber:

For high level insulated pipework or concealed insulated pipework:

No additional protective covering shall be required.

For exposed pipework at low levels:

Armaflex Tuffcoat or Arma-Chek Silver sheet (AF/Armaflex Class O self-adhesive sheet pre-applied with a PVC covering) sealed under compression at all seams and edges meet using Armaflex adhesive 520 or Armaflex adhesive RS850 and covered with Armaflex Tuffcoat or Arma-Chek Silver tape respectively along all joins. Installation shall be in all cases to the manufacturer’s recommendations. When installing Armaflex sheet to circular ducting, install and process the Armaflex as for large bore piping. For additional information consult the Armaflex Installation Manual.

04 – 02 External Coverings

Shall be:

For HT/Armaflex:

No covering shall normally be required when using HT/Armaflex outdoors due to the natural

in-built resistance against UV degradation.

For AF/Armaflex Class O elastomeric nitrile rubber:

Armaflex Tuffcoat or Arma-Chek Silver sheet (AF/Armaflex Class O self-adhesive sheet pre-applied with a PVC covering) sealed under compression where all seams and edges meet using Armaflex 520 adhesive or Armaflex RS850 non-drip adhesive and covered with Armaflex Tuffcoat or Arma-Chek Silver tape respectively along all joins. For Armaflex Tuffcoat external grade mastic should also be used to seal all seams to prevent water ingress. Insulation applied to the top horizontal surface of rectangular ductwork shall be installed so as to overlap and cover the top edges of insulation applied to vertical side panels to prevent water ingress. Installation shall be in all cases to the manufacturer’s recommendations.

Armafinish 99 UV resistant paint.

04 – 03 Vapour Barriers

Shall be:

For AF/Armaflex Class O Armaflex elastomeric nitrile rubber and Armaflex Ultima:

Built into the insulation material. The insulation shall have a moisture resistance factor no

less than 6,000. No additional external water vapour barrier shall be necessary.

For HT/Armaflex:

Built into the insulation material. The insulation shall have a moisture resistance factor no

less than 3,000. No additional external water vapour barrier shall be necessary.

04 – 04 Insulation of Ductwork Supports

Shall:-

Be applied such that ducts are acoustically de-coupled from the building structure. This clause will only be satisfied by the application of a flexible material between the ductwork and any pipe clips or hangers.

When ductwork (insulated or otherwise) is resting upon unistrut sections, high density rubber sections of “Armaload” as manufactured by Armacell UK Ltd shall be placed over the unistrut sections such that the duct rests directly onto the Armaload leaving no direct contact with the unistrut section.

04 – 05 Insulated Flange Covers

Shall be manufactured directly from the insulation material itself as according to the manufacturer’s recommendations. Insulation fabricated to cover flanges shall be the same as the insulation used on the remainder of the attached service ductwork.