(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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They are ductile and formable, but forming loads are higher than for mild steels and suitable, robust equipment is required.

Before duct manufacture it should be clarified that specified external duct dimensions allow for the lining thickness. Larger distances between floors than 5m.


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 Design Notes for Ductwork TM 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 action may not be reversed by the system.

Related Products DW The site storage of ductwork also introduces the additional important consideration of maintaining any factory applied protection and the internal cleanliness of the ductwork.

The principal mechanism for achieving this is through the replacement of existing national standards and technical approvals with a single set of European-wide technical specifications for construction products i. Illustrations indicating sealant locations will be found in the sections dealing with the construction of rectangular, circular and flat oval duct sections.


HVCA DW – Free Download PDF

Failure of the suspension devices does not constitute failure of the test specimen satndard it leads to failure of either E or EI. Ductwork hangers and supports.

If particles such as filings or grinding dust of a non-stainless steel or iron are brought into contact with a Stainless Stanard, subsequent exposure to moisture will lead to staining of the surface as these particles rust. This is not limited to the use of only these products but relates to all fire safety products.

If tested unprotected Steel Suspension devices Drop Rods can be used up to 1.

A ductwork system that has limited air leakage, within defined limits, will ensure that the design characteristics of the system can be maintained. Typical examples of the various methods of fixing to a structure are shown in Figs.

Requirements for ductwork components to facilitate maintenance of ductwork systems.

The movement of ductwork will inevitably involve manual handling. As the air supply creating the pressurisation must be maintained for the duration of the fire, fire dampers cannot be used dww144 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.

Standard Ductwork DW

Water based sealants should not be used on external ductwork. Any ductwork penetrating fire resisting barriers must be capable of providing the same period of fire resistance. Fire resisting duct sections. A full range of split ring brackets and support system manufactured in chemical resistant materials is available.


The CPR becomes a statutory requirement in each European country when it is incorporated in national Building Regulations. It may improve the sliding characteristics during forming operations and can be used as a primer coat for subsequent painting.

The HSE standardd a national registration scheme of safety consultants. This can also occur before a building is weathered where components are subject to a cycle of wetting and drying. In view of the foregoing, it is recommended that trials be carried out before starting production.

The system designer shall specify damper locations and select the damper type as defined in The coating mass is not always equally distributed on both product surfaces. Closer ztandard may be required by reason of the limitations of the building structure or to achieve the necessary duct rigidity. The duct is formed from a spirally- wound circular duct, using a special former.

Galvanized surfaces require chemical pre-treatment prior to painting. The surface has minimized spangles obtained by influencing the solidification process in a specific way.

Shoe branch similar to Fig also acceptable Fig. Informative publications on systems designed to control temperature, humidity and air quality in a defined space. All balancing dampers shall have a locking device located on the outside of the case and shall give clear indication of the actual blade position.