Category I Operational Aids and Alternative Measures

Category I operational aids include the following:

• A boom hoist limiting device for equipment manufactured after December 16, 1969. Note: There are some temporary alternative measures, such as a boom angle indicator or a clearly marked boom hoist cable, listed in this standard, as well as alternatives for equipment without a boom hoist limiting device and manufactured on or before December 16, 1969.
• A luffing jib limiting device (or temporary alternative as defined by this standard).
• An anti-two-blocking device for telescopic boom cranes manufactured after February 28, 1992 (or temporary alternative measure). Two-blocking is when the lower hook block is raised until it contacts any part of the boom tip hardware. It is a very dangerous situation that needs to be prevented.
• For lattice boom cranes, a device that either automatically prevents damage and load failure or warns the operator so he/she may prevent two-blocking. (Note that there are different requirements for cranes manufactured after Febrary 28, 1992 or November 8, 2011.)
• For articulating cranes manufactured after December 31, 1999, "a device that automatically prevents damage from contact between the load block, overhaul ball, or similar component, and the boom tip (or fixed upper block or similar component). The device must prevent such damage at all points where two-blocking could occur."

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