(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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Ducts smaller than these dimensions are, for access purposes, to be fitted with either flexible ductwork connections or removable duct sections. If users and system designers are in doubt as to which material is appropriate to a particular application, technical advice may stanfard obtained from from the British Stainless Steel Association www.

The dampers shall be constructed to prevent distortion and jamming in operation.


Arc welding of stainless steels. Accreditation is not mandatory. 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 ztandard the system as its action may not be reversed by the system. BS EN Extended applications of results from fire resistance tests for service installations.

Satndard are a non-profit group that run this website to share documents. It highlights the technical information to be provided by system designers to ductwork contractors and looks in detail at rectangular, circular, and flat oval ductwork.

Used for simple operations and designed up to mm on the longest side. Appendix H recognizes two main aspects of cleaning access: The information in this up-dated section is based on information kindly supplied by the Heating, Ventilation and Air Conditioning Association Dtandard and further information on this subject can be obtained from their web site at www.


This personal responsibility goes down to individuals who are using the building.

Standard Ductwork DW

All penetrations of the duct shall be fitted with suitable seals where necessary. This approach would realise the following benefits: Alternative sealant locations Fastening Alternative sealant locations Sealant shall be applied either internally or externally to the seam edge or internal to the joint seam itself.

To minimise the risk of damage it is recommended that before a contract is finalised, that consideration is given d144 the following subjects: The thermal insulation element of preinsulated ductwork should comply with the Building Regulations Approved Document L as per clause Full guidance with regard to risk assessment, maintenance etc is given in the RRFSO or its associated guidance. Some alteration in working practices may be necessary, depending on the type of Stainless Steel being used.

Illustrations of those most commonly used are shown in Figs.

Sheet metal air ducts with rectangular section. Specifications and test methods. Each range however has advantages and disadvantages with regard to both manufacture and installation costs. Curtain fire dampers generally provide an E classification to BS ENas they do not have the cold leakage characteristics to achieve the ES classification.

Control dampers control the airflow rate and in addition provide low leakage closure of the airflow. They are generally free as is ztandard associated government guidance. 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. This should be a clear reference for responsible persons and risk assessors.


It should be recognised that the testing of duct systems staandard a significant cost to the installation and incurs a great deal of extra time which needs to be pre-planned into the contract programme. The spread of fire to neighbouring construction works is limited.

The load-bearing capacity of the construction can be assumed for a specific period of time.

Duct work construction to DW/144

In the fully open position, the damper should have a minimum pressure drop. The relationship of the Pascal to other units of pressure is: Zinc, aluminium and their alloys.

The generation and spread of fire and smoke within the construction works are limited. BS Carbon steel plate, sheet and strip. This section highlights the importance of the selection of appropriate materials that will withstand the warm, humid and corrosive atmospheres associated standxrd such areas. It is recommended that a safety factor of 5 to 1 be added to calculations for attachments to the structure BS EN List of stainless steels.

The test standard for single compartment smoke control duct is BS EN In this case, there is increased risk of formation of corrosion products on the surface during storage and transportation.

However smoke control ductwork is covered by harmonised product standard BS EN which is published and so CE marking is required if the smoke control FPC ductwork comes within its scope. Bolts, parts screws, studs and nuts. Guide to Good Practice: A responsible person should be asking for all the Regulation 38 documentation when a building is handed over.

Heat Pump Guide TR