HVCA DW August 16, | Author: pheed5 | Category: Duct (Flow), Specification (Technical Standard), Screw, Building, Building Engineering. DW/ is recognised throughout the UK as the Standard Specification for ductwork manufacture and installation. It came into being in when it replaced. Kent Ductwork manufactures standard galvanised ducting to the DW specifications, which achieves all of the current BS, EN & ISO standards.

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The same methods are applicable to vertical flat oval ducts.

Duct sizes with an aspect ratio greater than 4: It is supplied in slit widths as specified by the customer, up to a maximum width of mm, depending on thickness. It raises awareness and provides guidance to building owners and all involved in the design, construction and operation of buildings and building services on how Failure of the suspension devices does not constitute failure of the test specimen unless it leads to failure of either E or EI.

Building regulations and ductwork leakage testing

A lustrous unidirectional finish produced by fine grinding, generally with abrasives of grit size. Loading of ductwork should be carefully planned to avoid crushing.

No individual damper blade should exceed mm in width. A trade organisation meeting the needs of building engineering services contractors involved with design, installation, commissioning, maintenance, control and management of engineering systems and services in buildings. The E-mail Address es field is required. It increases the protection against fingerprints. The ductwork construction and joint sealing standards are set out in Part Seven, Section Ductwork cleaning is a specialist contractor activity and would not be included for or undertaken by a ductwork installation contractor.

As a secondary precaution, polysulphide waterproof synthetic rubber sealant should be site applied to joint gaskets.

DW Specification for Sheet Metal Ductwork – The BESA

No paint protection is required. Specification for Sheet Metal Ductwork The industry’s comprehensive Specification for the manufacture and installation of sheet metal ductwork. This is applicable only to four-sided rectangular and circular duct.


Wire electrodes, strip electrodes, wires and rods for arc welding of stainless and heat resisting steels. Table 30 Rectangular aluminium ducts — low pressure constructional requirements Maximum duct Minimum sheet size longer side thickness 1 mm 2 mm 0.

Each roof opening should only have one duct passing through – not multi-service. Typical methods of supporting vertical rectangular and circular ducts are shown in Figs to F marked by 1 July It may be necessary to provide additional protective sheeting to stored ductwork to ensure the factory applied protection and cleanliness requirements remain in place.

A full range of split ring brackets and support system manufactured in chemical resistant materials is available. Design Notes for Ductwork TM These products are not allowed to have self-certification. Seams and cross-joints Figs to shall be sealed to ensure the necessary degree of airtightness throughout the pressure ranges covered in this specification.

Air leakage testing of high pressure ductwork is mandatory under the specification. The use of pre-painted strip in coil form provides a reliable quality finish and often proves more economical than painting after assembly. If selected for the protection of escape routes or sleeping risk areas they must have an ES classification. Smoke duct sections Reference Ducts for ventilation, pressurisation and kitchen extract Smoke control xuctwork Ensures that the Fire Duct Manufacturer has tested to the BS EN Standards at a Notified Certification body and has ISO quality systems for manufacture and installation of the duct system, and that the fire duct system has 3rd party certification for the manufacture and installation dw14 site.

Method for determination of the contribution of components to the fire resistance of a structure.

Galvanised Ductwork – Galvanised Ductwork DW 144

As the air supply creating the pressurisation must be maintained for the duration of the fire, fire dampers cannot be used within the ductwork to prevent the spread of fire as they will close on temperature increase, but use may be made of smoke control dampers, which may open or close depending on their position.


Again there may be more recent versions of the document. Care should be taken before selection any such units, with particular regard to an ES requirement, to ensure that all three restraints will be fulfilled. Appendix B, Clause B.

This responsibility de144 not handed over at any point. The relationship of the Pascal to other units of pressure is: They should point out any shortcomings too, although this would probably be seen with regard to blocked escape routes etc, not fire safety installations. Leakage testing is always done under positive pressure even when the ductwork is to operate under negative pressure.

Whilst some of the information may now be superseded, TM8 includes chapters on: The testing environment Leakage testing should always be ductdork under positive pressure even when the ductwork is to operate under negative pressure.

The materials used should be suitable for the purpose intended and satisfy the specified pressure classification. Hanger lengths greater than 1. Mechanical resistance and stability. Distortion shall be kept to a minimum. This is due to the naturally occurring chromiumrich oxide film which is present on the surface of the metal, if damaged, reforms immediately by reaction between the metal and the atmospheric or other source of oxygen.

Projection of a screwed rod hanger through the bottom bearer should be approximately twice the thickness of the securing nut. Further, unless the system designer has specified his requirements in detail, the load to be carried shall be understood to be limited to the ductwork and its associated thermal insulation.

Suppliers to confirm their suitability for the pressure classification dw14 which such casings are to be incorporated. By continuing to browse the site you are agreeing to our use of cookies.