Fabrication of Chimneys and Liners
JPen (John Patrick Engineering)

Fabrication of steel ducting and chimneys

JPen are experts in the supply of chimneys and ducting serving a variety of purposes: heat recovery and exchange (including Combined Heat and Power [CHP] systems), gas recycling, ventilation and system exhausts.

JPen ducting and chimneys are typically manufactured in mild steel, stainless steel or cromweld. Materials used for manufacture range from 1.5mm to 15mm thickness, dependent on the nature of the gases being transported.

As well as painted and galvanised finishes, JPen can arrange insulation and cladding of ducting and chimneys prior to or after installation. In addition, JPen supplies all necessary associated equipment, such as fans, dampers, supports, inspection points, access points and flexible joints for thermal expansion / movement and vibration.

Stainless steel ducting fabrication

Should the construction need to be highly resistant to corrosion and distortion then a stainless steel base material would be required as galvanised and mild steel materials would not be suitable. As any chemist would agree, the chromium content within the alloy is able to react with the air to form a chromium oxide barrier. The barrier is what protects the metal crystalline lattice from erosion, thus greatly extending the life span of the product. Stainless steel also provides superior strength and durability, taking these factors into consideration including the longevity of the product will yield a cost effective option over the spend life cycle.

The welding skills required to join stainless steel are highly experienced to expert. It is crucial for all welds to be structurally sound though the fabrication process.

JPEN applications of steel ducting

A strong demand for JPen’s work resides in providing bespoke venting and air way solutions for factories, processing plants and commercial buildings. Whilst the majority of projects tend to be focused on exterior venting, the company portfolio includes numerous custom made internal mild steel ducting arrays, predominantly created for heating ventilation and air conditioning systems.

Due to the internal setting and therefore protection from an external environment, the galvanisation process on the mild steel is adequately sufficient to provide anti-corrosion protection for the daily of this type of ducting system.

Supporting infrastructure for steel ducting and chimneys

The main stacks and sections of both ducting and chimneys will always be supported by lattices and quite often access gantries and walkways. JPen fabrication operations can also design and provide the appropriate supporting structures to locate, fix and secure any constructions of this type.

All work is carried out to meet both the requirements of the customer and to fulfil the controls of both the ISO 9001 and BSEN 1090, JPen currently hold Ext level 3 for the 1090 classification, relating to the type of project and its ultimate use and of course environment.

Closing considerations

Working with stainless steel has a higher cost factor, due to the increased craft skill required, the cost of the raw material which is driven by supply and demand as well as energy prices. This being said, the payoff does come from the impressively long life span offered by stainless steel over galvanised and mild steel.