Fabrication:
Fin Material: Aluminum
Tube Material: Any metal
L Fin Design Temp: <300°F @ <150°C
Overlap-L Design Temp: <350°F @ <180°C
Application:
L fin offers a certain degree of atmospheric protection of the tube wall against corrosion. The broad contact surface between the tube and the finning enhances heat transfer. This fin design is the most economical.
The LL fin design called is simply because the L foot of the overlapped onto the previous L foot. This results in a slightly higher level of tube corrosion protection and allowable design temperature.