(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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Users should ensure that they consult with the latest version. Syandard ducts shall be securely fastened at each end using a proprietary band such as a plastic tie-wrap. EN lists the grades of steel set out in the columns below, among others: The extracts from BS. Minimised spangle is generally the most widely available product. Helium or a mixture of helium and argon can be used, but not C The more commonly used steels divide into two main families; the lower alloy ferritic The test standard for multi compartment smoke control ductwork is BS EN Also take into account any material acceptance rules imposed by the main contractor.
They should point out any shortcomings too, although this would probably be seen with regard to blocked escape routes etc, not fire safety installations. BS EN Ventilation for buildings. Bolts, parts screws, studs and nuts. Immersed components are not at all susceptible to SCC.
HVCA DW 144
Arrangements for flat oval duct supports are shown in Figs. They are generally free as is the associated government guidance. BS EN Fire classification of construction products and building elements. The requirements for direct dww144 of application of the test results of all duct tested to BS EN apply together with the following; a.
Particular care must be taken in the sealing of these joints. A CE mark means that a manufacturer claims that their product conforms to the minimum legal requirements for health and safety as laid down in EU directives. The intumescent materials form the main component for fire integrity. The new regulations combine the Construction Health, Safety and Welfare Regulations and CDM into one single set of regulations which introduce some important changes to the safety regime.
These procedures are to obviate any particle migration. If airtight, waterproof flexible insulation jackets are applied on positive pressure ducts, the insulation should accommodate some duct leakage: This would normally be achieved by an electric solenoid or electromagnet. First Edition Second Edition further copies of this publication are available from: The use of third party certificated products and installers is clearly recommended. Designations of the most common Stainless Steel grades are given in Tables 28 and The basic requirements for storage are: Steel products shall be protected against corrosion and supplied in a fully assembled condition as specified by the system designer.
HVCA DW – Free Download PDF
The finish may be specified if the normal spangle applicable does not satisfy the surface tsandard requirements. Shoe branch similar to Fig also acceptable Fig. They are ductile and formable, but forming loads are higher than for mild steels and suitable, robust equipment is required. It should be noted however that any secondary steelwork required to achieve maximum support spacings, for example: Aerodynamic testing of dampers and valves.
With socket and spigot joints, care should be taken to ensure that the dimensions of ducts and fittings are correctly related. The coating mass is not always equally distributed on both product surfaces. It is becoming common practice for the types of structural stanxard to be specified by the main contractor on a project by project basis.
Larger distances between floors than 5m. Classification using data from fire resistance tests stnadard products and elements used in building service installations: In all cases the paint manufacturer should be consulted regarding suitability for the intended application.
Metallic and other inorganic coatings. Swimming pool buildings have the additional complication of a large variations in conditions which can standsrd in a pool environment. Galvanized surfaces require chemical pre-treatment prior to painting. For the same reasons, floor supports have not been dealt with.
Test results achieved for horizontal ducts A and B are applicable to horizontal ducts only. Ignitability of products subjected to direct impingement of flame. A responsible person should ask if they are not sure. In the fully open position, the damper should have a minimum pressure drop. Systems that are immediately identifiable as fire rated minimise the risk of unauthorised modifications i. Within the requirements of the European directive, da144 fire marked by have 1 Julyan Classification using data from fire resistance tests on components of smoke control systems.
System design should take into account stanadrd need for future inspection regimes and the maintenance access available to the ductwork and its associated supports.
The ductwork should have a weathering cravat to fit over the kerb. If particles such as filings or grinding dust of a non-stainless steel or iron are brought into contact with a Stainless Steel, subsequent exposure to moisture will lead to staining of the surface as these particles rust.
They are very limited and cannot simply be applied by a manufacturer.