Chris Ridge is Technical Policy Manager for the Thermal Insulation Contractors Association and a TIPCHECK expert
Thermal insulation is an often misunderstood and overlooked specialist trade, and the long-awaited new update to standards should be welcomed by the building industry. After all, pipe and duct thermal insulation is an established means of reducing carbon emissions, so how it is specified and installed is critical.
British Standard 5422 is relied upon to provide consultants and contractors with key guidance on what a good thermal insulation specification looks like. There are several key changes to BS 5422:2023 to specify thermal insulating materials for pipes, tanks, vessels, ducts and equipment operating between -40ºC and 700ºC. And while there are some missed opportunities, I’d like to start by focusing on the many positives.
BS 5422:2023 provides much-needed clarity regarding minimum reaction-to-fire standards for pipe and duct insulation. There is a definitive departure from BS 476 and the legacy of ‘Class O’ declarations following the adoption of the Euroclass reaction to fire standards. BS 5422:2023 sets out a minimum reaction to fire performance of Euroclass C-s3, d0 in residential applications and B-s3, d0 in non-residential applications.
“An increase in the large number of options can lead to more confusion”
The use of A1, A2 or B rated products is already an accepted practice in the thermal insulation industry, but in recent years our sector has witnessed a proliferation in the use of pipe and tube products pre-insulated ducts with Euroclass D or E classification inside. buildings Fortunately, BS 5422:2023 has established a clear line of acceptability that both contractors and specifiers can easily refer to.
The new standard publishes tables that provide minimum insulation thickness for both building services (including refrigeration, air conditioning, heating, and domestic hot and cold applications) and industrial/process piping applications. Throughout the document an attempt has been made to simplify the tables by, for example, removing higher thermal conductivity values for materials that are no longer supplied or are rarely used.
Possibility of carbon reduction
There are several new tables detailed in the document. Thermal insulation of pipes and ducts can play an important role in reducing energy loss and it is therefore very positive to see the addition of tables covering improved insulation thicknesses and district heating thicknesses. This will give the sustainability-conscious engineer more options when looking for ways to reduce a building’s lifetime carbon footprint.
However, an increase in the sheer number of options can also lead to more confusion as both specifiers and installers wonder which table should be used for which application. For example, there are now 10 separate tables detailing insulation thicknesses for low temperature heating, including ‘base level’ tables.
It was a golden opportunity to eliminate the base level boards for low temperature heating and domestic hot water applications, and effectively advance the minimum standards required to reflect the more demanding “enhanced thickness” boards. In many cases, thermal insulation specifications already exceed the base level tables published in BS 5422:2023. With more and more specifiers focused on carbon reduction targets, we can expect base-level tables to become a victim of best practice rather than a driver of best practice.
There is also the pending issue of aligning BS 5422:2023 with BS EN ISO 12241:2022 (Thermal insulation for building equipment and industrial installations – Calculation rules).
Hopefully there will be an opportunity to revisit some of these considerations sooner rather than later. In the meantime, this is perhaps a good opportunity for specifiers of thermal insulation systems to take a close look at the options presented in BS 5422:2023 and consider carefully what they want to achieve with their thermal insulation specifications.
Specifiers should also consider how they might ensure that their specifications are unambiguous and enforceable. Given the industry-wide effort to reduce carbon emissions, we all benefit if thermal insulation is specified and installed correctly.
