+44 (0) 1723 502 440 sales@firthsheetmetal.com

DW144 Ductwork

Since it first marketed its services in 1964, the specialists at Firth Sheet Metal have used the collective experience of their 15-strong team to provide a service of enviable quality. We focus on designing, delivering and manufacturing tailored systems suitable for a variety of heating, ventilation and air conditioning technologies, and all within a quick turnaround period. But where others merely provide supply, we prefer to focus on providing the solution. While our product is of an exemplary standard, our primary selling point is arguably our sheer breadth of knowledge. We are proud of our ability to provide an end-to-end service to our customers, where our sheetmetal workers and project engineers will coordinate with our customers from consultation to design, installation to system commissioning.

The clients we work with include some of the country’s largest construction firms and engineering companies, many of whom require complex ductwork systems as part of their contracts. However, one of the primary elements of our service resolves around the building, supply and installation of ductwork; one of the many benefits of using us as the provider of sheet metal. We are one of the few UK manufacturers licensed in their design, with stock including the standard DW144 Duraduct models and the more advanced versions; notably the Duraduct LT and Fireshield versions. Our ductwork straights and fittings come manufactured with rolled on flange, primarily done using equipment such as Firmac CNC. 

Our standard versions adhere to all associated manufacturing and installation guidelines. Given our history in the industry, it is no surprise that we have developed a particularly prominent reputation for providing excellent advice and support with regards to DW144 installations. 

Aside from ductwork, we are capable of providing a range of other products including fans, ventilation systems and other general extraction and ventilation technologies, including dust and flame extraction.

While other manufacturers might focus on products, we deliver turnkey projects. Given the breadth of our offering, it is important that we do not attempt to push any one service or product on our customers. Instead, we leave it to our customers to tell us what they need from us, adapting our offering accordingly. Some clients may need us to work to designs they supply us, or we can merely provide design support through a CAD system. Some customers need products to be manufactured and installed, while others rely on us to deliver design elements instead. 

Whatever the requirements, our highly experienced and qualified team are more than capable of rising to the challenge. If you would like to learn more about our products and services, feel free to get in contact with a member of our team and find out what we can do for you.

Our Customers

DW144 Ductwork

All our products are manufactured to the highest standards, in-line with DW144 specification for sheet metal ductwork. All sections are produced with an integral continual girth flange from one complete section of steel sheet. This delivers strength and quality far beyond the requirements of DW/144.


We are one of only a few UK companies licensed to manufacture Flameshield fire rated ductwork, compliant to BS 476 part 24. This is a non-coated, certified fire-rated ductwork system made from galvanised sheet metal on our dedicated machinery, which delivers performance and reliability expected of a leading brand.

Duraduct Lt®

We are one of only a few UK companies licensed to manufacture Promat DURADUCT LT,a Durasteel based fire rated product, compliant to BS 476 part 24 which provides up to 240 minutes fire resistance. This highly moisture resistant product retains integrity even when saturated, and does not absorb fluids such as cooking oil in kitchen extract systems.


At Firth Sheet Metal Ltd we can produce ductwork to customer drawings; or can provide a complete design service including, comprehensive site surveys, detailed 3D CAD drawings, and design calculations, all available for inspection if required. Our team have experience from a vast array of industries, and will work with you to provide the solutions you need.


Our 700m2 workshop is equipped some of the best tooling and machinery available, including Firmac CNC equipment, allowing our highly trained staff to provide top quality products. We pride ourselves in offering these high quality products quickly and efficiently at competitive prices.


As an accredited safe contractor we have a track record for excellence in health and safety. This is evident when working with our fully trained installation engineers. We are committed to safe and smooth installations from start to finish, and all staff have the necessary skill cards, IPAF training certificates.