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BESA TB61 (August 2025) updates the recommended identification colours for ductwork. One of the key changes is that General Extract Air should now be identified using Yellow triangles (BS 4800 ref. 10 E 55). Previously, Grey triangles were commonly used for Extract Air. The guidance removes Grey to improve visibility and contrast.

Grey triangles were used historically to indicate Extract Air. TB61 recommends Yellow instead, but there will be a cross-over period where some specifications and projects still call for Grey. For this reason, Albion Systems continues to supply both Grey and Yellow triangles, depending on customer and project requirements.

Physically, the triangles are identical in size and colour (Yellow, BS 4800 10 E 55). The difference lies in what specifiers call them:

- Under DW/144 (earlier guidance), Yellow was used for Warm Air.

- Under TB61 (new guidance), Yellow is recommended for General Extract Air.

Therefore, the same Yellow triangle can be used for either application, depending on specification. Albion Systems lists this under product code DUCTM02.

- Grey – Extract Air: DUCTM04

- Yellow – Warm Air / General Extract Air: DUCTM02

These codes remain consistent across our catalogue. The difference in naming is due to evolving standards, not different products.

Our literature and website were printed prior to the release of TB61. As a result, some documents show Yellow as “Warm Air”. This will be updated to reflect that Yellow triangles can now also represent General Extract Air. Until then, please note that DUCTM02 covers both descriptions.

This depends on the project specification:

- If your specifier, consultant, or site still calls for Grey for Extract Air, we can supply DUCTM04.

- If the project follows the latest BESA TB61 guidance, then Yellow (DUCTM02) should be used for General Extract Air.

Albion Systems supplies both options to give customers flexibility during this transition period.

According to industry updates, there may be a future change to the British Standard to align with duct labelling (timeline 6–24 months, exact date unknown). For now, TB61 is guidance, not a legal requirement. We recommend confirming with your specifier or client which standard they want followed.