This part of ISO 6743 establishes the detailed classification of fluids of family T (Turbines) that belong to class L (Lubricants, industrials oils and related products). It is intended to be read in conjunction with ISO 6743-99[2]. This classification excludes the products intended for aircraft turbines. However, some aircraft turbines can find land application for power generation. For the lubrication of such turbines, it is recommended that the manufacturer’s recommendation be followed. Depending on the service, either TGA, TGB, TGCH, TGCE or more specific aircraft-turbine lubricants can be used. This classification also excludes the products intended for the lubrication of wind turbines. The gear lubricants used in wind turbines are described in ISO 6743-6[1] and specified in ISO 12925-1[3].