(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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Commercial and Legal Useful information regarding the rights and duties of parties engaged in trade and commerce Read More.

Local discolouring as a result of this treatment is permissible dw1444 does not impair the quality.

Standard Ductwork DW

Fire tests on building materials and structures. All the seams and joints integral to a fitting shall be sealed to the same standard as the duct. It shall be standard practice to provide access panels for the inspection and servicing of plant and equipment as listed below.

Spindles shall be carried in either non-ferrous, synthetic or roller bearings. See Sections 26 and Any additions to this would normally be the responsibility of others. The duct is formed from a spirally- wound circular duct, using a special former. These are; 1 2 3 4 Insulation Integrity Smoke leakage Stability Direct field of application The direct field of application only covers circular and four sided rectangular ducting at this time.

All products shall be protected against corrosion as necessary and supplied in a fully finished condition as specified by the system designer. They are aimed at improving the management of health, safety and welfare to reduce the large number of serious and fatal accidents which happen every year in the industry.

Such fixings must not be used within 1 metre of an access opening ds144 as BS Enclause 4. Legislation and accountability for Fire Safety Products is a critical aspect in the manufacture of fire resisting ductwork and this section must be read in conjunction with Appendices L and M and Commentary and Guidance Note 5.

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.



Suppliers to confirm their suitability for the pressure classification in which such casings are to be incorporated. BS EN Cold rolled low carbon steel flat products for cold forming. Basements with natural ventilation should have a permanent opening, not less than 2. Test results achieved for horizontal ducts A and B are applicable to horizontal ducts only. This means under the field of direct application, the largest ducts, for duct A and B will be mm wide x mm high for rectangular ducting and mm diameter for circular ducting.

DW Specification for Sheet Metal Ductwork – The BESA

These standards for smoke control ductwork and dampers may become applicable within the life of this standard and then similar procedures should be followed as that which are followed for fire dampers above, but using the published standards for smoke control products. Iris dampers are available for circular ducts only, in diameters up to mm It should be noted that the damper casing may be up to twice the diameter of the duct. Ignitability of products subjected to direct impingement of flame.

The reason being that if a duct under a negative pressure fails a leakage test it is impossible to identify the leakage path. Share Share Share An opportunity to contribute your knowledge to a number of key industry focus areas Read More. Stainless Steel has been developed to cover a wide range of uses where high resistance to corrosion and low maintenance costs are important.

According to the Regulations, the requirement for CE marking will apply to: Stainless Steel also finds application in exposed ductwork where the finish can be used for aesthetic reasons. Any ductwork penetrating fire resisting barriers must be capable of providing the same period of fire resistance.

Helium or a mixture of helium and argon can be used, but not C Fire Outside duct A plus mm wide, plus mm high for rectangular ducts plus m diameter for circular ducts. Maintenance Agreement EA 1: For this purpose, the damper blades are set and locked manually in any required position between fully open and fully closed. A uniform matt finish. As a general rule, Stainless Steel should be kept free from iron dust and debris contamination. Tata Steel are able to provide further detailed information on the subject of coil sgandard recommendations and practices on their website.


Repeated bending is not recommended. All are weldable and have good general corrosion resistance to normal and mildly corrosive atmospheres. Ventilation All the information needed to move air into and out of an interior space by mechanical means Read More. System design should take into account the need for future inspection regimes and the maintenance access available to the ductwork and its associated supports.

Fastenings shall be as for rigid circular ducts Section If not used, the toe of the angle is to standarx sealed.

Sustainability Browse our range of good practice sustainability guides Read More. This is not limited to the use of only these products but relates to all fire safety products. Typical examples of the various methods of fixing to a structure are shown in Figs.

Don’t Forget – TR/19 states that you will need a

The maximum available width can vary according to the steel thickness required. BS EN Continuously hot-dip coated steel flat products. For the same reason, changes to any dampers specified in a design should only be undertaken with very careful consideration.

BS EN Smoke and heat control systems. Recommendations for welding rw144 metallic materials.

The blades shall close the airway by means of a spring sthe spring element being incorporated within the damper or actuator stanadrd. Some re-adjustment is possible but small radius bends cannot be straightened without leaving some distortion of the corrugations.

However, developments in technology and working practices, along with the need to reflect a steady proliferation of European standards, have rendered necessary a far-reaching revision of the original edition. A turn up as illustrated is not mandatory. However, it is generally accepted that in typical good quality systems the leakage from each class of duct under operating conditions will be in the region of: Design Notes for Ductwork TM