The Association said member firms are losing work due to competitors using cheaper Euroclass F, non-certified polyisocyanurate (PIR) board, on external ductwork.

Chris Ridge, TICA Technical Director said: “There are several manufacturers of PIR board operating in the UK and TICA is aware of only one PIR product that is certified for specific use with externally located ductwork.

“We have witnessed the use of many different PIR brands and clearly many of these have not been certified for the required application. 

“Everyone in the supply chain must ensure that the correct products are being used. Manufacturers, distributors, and installers all have a responsibility.”

He added: “Manufacturers need to be clear and unambiguous about where their product can and can’t be used. The one manufacturer that has certified their PIR product for use with ductwork is very clear about the fact that its product is only suitable for externally located ductwork.

“The ambiguity that exists elsewhere will only increase the chances of PIR products being used in internally located ductwork applications. 

“Clients also need to take responsibility and ensure that they employ only competent specialist subcontractors to insulate ductwork.”