Technical Booklet L Combustion Appliances and Fuel Storage Systems·Page 63·Table 4.4
Minimum performance designations for chimney and flue pipe components for gas appliances
Table specifying minimum performance designation requirements for different types of gas appliances including boilers, gas fires, and air heaters in both open-flue and room-sealed configurations.
Minimum performance designations for chimney and flue pipe components for use with new gas appliances
Appliance type | Minimum designation
Boiler: open-flue Natural draught | T250 N2 D 1 O
Boiler: open-flue Fanned draught | T250 P2 D 1 O
Boiler: open-flue Condensing | T140 P2 W 1 O
Boiler: room-sealed Natural draught | T250 N2 D 1 O
Boiler: room-sealed Fanned draught | T250 P2 D 1 O
Boiler: room-sealed Condensing | T140 P2 W 1 O
Gas fire Radiant/convector, ILFE or DFE | T250 N2 D 1 O
Air heater Natural draught | T250 N2 D 1 O
Air heater Fanned draught | T250 P2 D 1 O
Air heater SE-duct | T250 N2 D 1 O
Notes:
(1) The designation of chimney products is described in Appendix B. The BS EN for the product should specify its full designation and marking requirements.
(2) These are default designations. Where appliance manufacturer's installation instructions specify a higher designation, this should be complied with.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet L - Combustion Appliances and Fuel Storage Systems.pdf