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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Factory-fitted proprietary synthetic rubber gaskets of the o-ring or lip-seal type are also acceptable for socket and spigot joints on circular dw414 systems Energy economy and heat retention.
DW 144: Specification for Sheet Metal Ductwork
It is important to note that system designers can achieve significant cost savings by matching operating pressures throughout the system to constructional standards and appropriate ductowrk leakage testing.
Designations of the most common Stainless Steel grades are given in Tables 28 and Any ductwork penetrating fire resisting barriers must be capable of providing the same period of fire resistance.
If it requires long lengths of lined duct to achieve the reduction in sound level then the proprietary attenuator becomes an economic alternative. However, it is generally accepted that in typical good quality systems the leakage from each class of duct under operating conditions ductwofk be in the region of: The product construction standards require that the duct is tested to at least one of the wd144 test standards.
However, any chloride-based material, such as polyvinyl chloride PVCshould be avoided, as breakdown of such material at certain elevated temperatures could lead to corrosion of the Stainless Steel.
The initial approach is to gather information, followed by a detailed evaluation which will be presented in a formal report.
Ductwork made from insulation duct boards. Printable View E-mail Bookmark.
Building regulations and ductwork leakage testing
The Red document status indicator indicates that the document is an old version The document euctwork likely udctwork withdrawn by the publisher, also the meta data presented here may be out of date as it is no longer being maintained by the editorial teams at NBS.
Specifications and test methods. Where the smoke extract ducts pass through into other fire compartments, it must be tested to BS EN Manufacturers of flexible ductwork will normally provide pressure drop data to a system designer to suit the anticipated ductwork configuration. This consideration should ductwofk include recognition of all appropriate risk assessments.
Duct sizes with an aspect ratio greater than 4: To satisfy this requirement it is now possible to purchase kits with a recognised third party UKAS certificated safe working load incorporating recommended minimum safety factor of 5 to 1 covering the complete suspension from the building structure to the ductwork.
CE marking requires full testing supported by third party certification.
No paint protection is required. The safety of rescue teams is taken into consideration. There is no restriction on the size of duct in which multi-blade dampers or damper assemblies may be used. A detailed specification of materials and method of application is required. Forming characteristics are similar to those of mild steel, so it can be worked using conventional practices. Leakage Class Sheet No. Flexible ducts shall be securely fastened at each end using a proprietary band such as a plastic tie-wrap.
Accreditation means the certification body can demonstrate that it has been successful in meeting the requirements of international accreditation standards.
HVCA DW – Free Download PDF
For fire safety products with relevant harmonised product standards such as fire resisting ductwork, fire dampers, smoke control dampers, etc, it is a requirement of CE marking. A ductwork system that has limited air leakage, within defined limits, will ensure that the design characteristics of the system can be maintained.
There are compositional variants within this family, designed to give specific formability and welding characteristics. If necessary, basic roof discharge cowls for circular systems should be sized to suit Fig.
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 ew144 be under the control of d144 system as its action may not be reversed by the system. In all cases the paint manufacturer should be consulted regarding suitability for the intended application.
If required, in the event of a signal from a remote sensor activation of this device would be achieved by an actuator, electrical solenoid, electromagnet, or other device. My Orders Details of your purchase history Read More. Please choose whether or not you want other users to be able to see duvtwork your profile that this library is a favorite of yours.
Swimming pool buildings have the additional complication of a large variations in conditions which can exist in a pool environment. Excessive sag and deviation of the duct should be avoided and it may therefore dw144 necessary to provide supports for the flexible dw144 at approximately 1. As flexible ducts have a higher resistance factor than conventional ductork of the same diameter, it is generally recommended that in any application the length does not exceed 6 x diameter but this can be varied if due allowance is made in the system design for the pressure drop.
Used for simple operations and designed up to mm on the longest side. See Figs to The information in this section is based largely on information kindly supplied by the following two associations: