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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It has little specular reflectivity. However, formatting rules can vary widely between applications and fields of interest or study. Most read stories over the last six months. Worksafe – Safety Facts JS 2: BS Schedule of ductwodk colours for building purposes. Service ducts and shafts. The drop rod should be tested inside the furnace and subject to the maximum weight that the drop rod would have to bear in practice.


Closer spacing may be required by reason of the limitations of the building structure or to achieve the necessary duct rigidity. Projection of a screwed rod hanger through the bottom bearer should be approximately twice the thickness of the securing nut.

Surface area x Max. The designated Director has the overall responsibility for ensuring that company knowledge is updated on current legislation, guidelines and codes of practice, and the dissemination of this information to employees and sub-contractors. In the course of dipping into the molten zinc bath, unsightly panel distortion will ducctwork due to the relief of inherent stress in the steel sheet and any stresses that may have been built into the item during manufacture.

BS EN Continuously hot-dip zinc coated low carbon steels strip and sheet for cold forming. Fastening Alternative sealant locations Fig Alternative socket and spigot duct to duct with connector. The test results on the duct are applicable to the following under and over pressures depending on the tested pressure.

Materials used should be suitable wd144 the purpose intended and satisfy the specified pressure classification.


For cooled systems, it is also important to ensure that the risk of condensation is adequately controlled. It is particularly important that such a panel is accommodated for the inspection of bird mesh screens fitted behind louvres.

EN sets out requirements for continuously hot-dip coated products made of low carbon steels for cold forming with zinc Z zinc-iron ZFzincaluminium ZAaluminium-zinc alloy AZ and aluminium-silicon alloy AS. Please enter the message. BS EN — 3 or 4 define how to give a fire resistance classification as a result of testing.

Material ducteork of ductwrok, section and fixings is not always assured in practice due to commercial availability. In the case of fire-resisting dw144 systems particular care must be taken to ensure that any retro-fitted access panels are suitably fitted, under licence to the fireresisting systems manufacturer.

DW 144: Specification for Sheet Metal Ductwork

By continuing to browse the site you are agreeing to our use of cookies. Informative publications on systems designed to control temperature, humidity and air quality in a defined space.

A smooth finish brighter than 2D. TICA ductwrk able to advise on the recommended clearance dimensions for insulating ductwork. A full range of split ring brackets and support system manufactured in chemical resistant materials is available. The product construction standards require that the duct is tested to at least one of the following test standards.

Users should ensure that they consult with the latest version. This responsibility is not handed over at any point. Related Products TR This is because, if a duct under a negative pressure fails a leakage test, it is impossible to identify the leakage paths.

The system designer also needs to confirm that the support allows for continuing the vapour seal by extending any spacer past the support device. Each roof opening should only have one duct passing through – not multi-service. In contrast to international standardization, it can have a quasiregulatory role in certain cases. We firmly believe that this process has resulted in a publication that clearly demonstrates the high level of professionalism which exists within the ductwork community — and we take this opportunity of thanking all those who have contributed to its production.


Repeated bending is not recommended.

The blades shall be simultaneously adjusted by a quadrant or similar operating mechanism. Spindles shall be carried in either non-ferrous, synthetic or roller bearings. Click here to find out how to access this document. They are ductile and formable, but forming loads are higher than for mild steels and suitable, robust equipment is required.

DW Specification for Sheet Metal Ductwork – The BESA

Duct sizes with an aspect ratio greater than 4: Considerations during design, manufacture and installation At the design stage, it is possible to forecast with reasonable accuracy the total loss from a system by calculating the operating pressure in each section, the surface area of the ductwork in each corresponding pressure section and the allowable loss at the operating pressure for each section.

Minimum steel thicknesses related to duct dimensions are given in Table Where dampers are required for blade lengths in excess of mm, the blades should be suitably re-inforced or supported. BS EN Reaction to fire tests for building products. Certain regulations require particular records to be produced, kept or maintained. A lustrous unidirectional finish produced by fine grinding, generally with abrasives of grit size. Add a review and share your thoughts with other readers. Fire resistance tests for service installations.

It also gives guidance on the continuing maintenance for smoke control systems, ventilation ductwork and other equipment with fire safety performance or requirements. It will also ensure that energy and operational costs are maintained at optimum levels. Fire dampers must not be installed in extract ductwork serving car parks, however smoke control dampers could be used. There are four classes of duct construction to correspond with the four pressure classifications: