• June 20, 2019

(a) DW/ Specification for sheet metal ductwork (low-medium- and high pressure) .. Air leakage of the assembled unit shall be to HVCA Standard DW/ Duct Work Construction to DW/ DW/ is recognised throughout the UK as the Standard Specification for ductwork manufacture and installation. “It will be. DW/ Specification for. Sheet Metal Ductwork. Low, medium and high has gained national and international recognition as the industry standard.

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The choice between the available methods of fixing will depend on the type of building structure and on any limitations imposed by the structural design. Aerodynamic testing of dampers and valves.

DW Specification for Sheet Metal Ductwork – The BESA

Some proprietary systems of support for vapour sealed ducts are available. Care shall be taken to ensure that the integrity of any vapour seal is maintained and reference in this respect must be made to both BS and BS It may be necessary to provide additional protective sheeting to stored ductwork to ensure the factory applied protection and cleanliness requirements remain in place. The implementation of an Environmental Management System EMS can assist a business in managing and meeting its increasingly heavy burden of responsibility for the future protection of the global environment.

The design of swimming pool ductwork systems and their supports is the responsibility of the system designer and not the ductwork contractor. The CPR builds on the success of the CPD, by allowing construction products that have been assessed standarv harmonised standards to be legally placed on the market anywhere in the European Economic Area. Curtain fire dampers generally provide an E classification to BS ENas they do not have the cold leakage characteristics to achieve the ES classification.

The ductwork contractor shall provide documented evidence of the calculations used to arrive at the allowable loss for the section to be tested and the client, or his agent, shall witness and sign the results of the test. Tolerances, dimensions and sectional properties.

The Regulations place duties on all those who can contribute to the health and safety of a construction project. Dampers that are designed to fail open using a thermal operating element at the outside of the building or in a collection area may be used, noting that once this device has operated, the unit ceases to be under the control of the system as its ds144 may not be reversed by the system.


Fixing bolts required at each corner and at mm centres.

Fire dampers must not be installed in extract ductwork serving car parks, however smoke control dampers could be used. Stainless Steel also finds application in exposed ductwork where the finish can be used for aesthetic reasons. The load-bearing capacity of the construction can be staandard for a specific period of time.

Generally they are called for where ducts penetrate walls or floors which form fire compartmentation. ADB gives guidance on fire safety information if required at building completion or occupation – whichever is earlier. Supports for ductwork external to the building have been excluded, as these are individually designed to suit the circumstances, and also may be required to meet local authority standards.

The test standard for single compartment smoke control duct is BS EN BS EN Continuously hot-dip zinc coated low carbon steels strip and sheet for cold forming. Typical materials are hardwood or treated softwood srandard separate block form for circular ducts — see note below: The requirements for flat oval duct fittings apply throughout the pressure ranges covered in this standrd. Building products excluding floorings exposed to the thermal attack by a single burning item.

It is not practicable to deal here with the full range of supports available, which increasingly includes proprietary types such as wire rope suspension systems, so in this section various methods of support are dealt with in principle under the three elements of: Fire brigades will seek changes under this legislation if they find discrepancies and will start court proceedings if they find major problems that have not been put right. Projection of a screwed rod hanger through the bottom bearer should be approximately twice the thickness of the securing nut.

In the case where galvanized sheet steel ductwork is clad with the application of protective material, the ductwork construction must be as type tested and comply with the protective material manufacturers recommendation, e.

The system designer must specify material type, thickness, and application method. A bright, non-directional reflective finish with a high degree of image clarity.


The Commissioning Codes give a guide to design implications.

Duct work construction to DW/144

Certain regulations require particular records to be produced, kept or maintained. No third party certification means no CE mark. Thank you for interesting in our services. Ventilation All the information needed to move air into and out of an interior space by mechanical means Read More.

Classification using data from fire resistance tests on components of smoke control systems. This finish is obtained when the zinc coating is left to solidify normally. The edition of Approved Document 7 will continue to apply to work started before 1 July or subject to building notice, full planning application or initial notice submitted before 1 July A large number of injuries at work are caused by accidents during this process through poor handling techniques.

If consideration is being given to either higher pressures or flat oval ductwork then it would be prudent for the system designer to seek advice from manufacturers who have the experience and capacity to manufacture aluminium ductwork. Systems that are immediately identifiable as fire rated minimise the risk of unauthorised modifications i.

A responsible person should ask if they are not sure. A local excess temperature in the area of the fire damper shall, independent of any remote sensors, automatically release the blades and close the airway by means of the thermal release mechanism.

The use of third party certificated products and installers is clearly recommended. Develop Develop Develop Find out about the latest industry specific training courses and apprenticeships Read More.

DW 144: Specification for Sheet Metal Ductwork

The more commonly used steels divide into two main families; the lower alloy ferritic Fire resistant ductwork covered by Product Standard prEN will Within F of the standard is qualified t require mandatory mark. The tested duct assembly is judged against five performance criteria.

Refer to right hand page opposite for additional information relating to Notes 10 to 13 in Table 3. The principle to be followed should be to make seams and joints as unobtrusive as possible.