B30.6 applies to the construction, installation, operation, inspection, testing, and maintenance of guy, stiffleg, basket, breast, gin pole, Chicago boom, shearleg, and A-frame derricks. These derricks, powered by winches through systems of wire rope reeving, are used for lifting, lowering, and horizontal movement of freely suspended unguided loads. Derricks are usually stationary mounted and may be temporarily or permanently installed. The provisions included in this volume also apply to any variations of these types of derricks with the same fundamental characteristics, except those specified for floating derricks in ASME B30.8, Floating Cranes and Floating Derricks.