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Types of Crane Service

Crane Service Ratings

To help users select the most appropriate and economical type of crane for their specific industrial and construction needs, the Crane Manufacturers Association of America, Inc. (CMAA) has developed a listing of six service classes. These classes define the required intensity of each type of crane service.

The types of crane service by class are as follows:

Class A (standby or infrequent service) – covering cranes used in power houses, turbine rooms, power utilities, motor rooms and transformer stations or any other type of installation that requires precise movement at slow speeds with long idle times between lifts.

Class B (light service) – for cranes that may be used for light assembly operations, light warehousing, repair shops and service buildings. This type of crane service involves light loads at slow speed, possibly two to five lifts an hour, averaging 10 feet per lift.

Class C (moderate service) – for cranes used in machine shops or paper mill machine rooms, for instance, handling loads that average 50 percent of rated capacity, with five to 10 lifts an hour, averaging 15 feet with not more than 50 percent of the lifts at rated capacity.

Class D (heavy service) – for cranes used in foundries, heavy machine shops, steel warehouses, container yards, foundries, and standard duty and magnet operations. This type of crane service involves constant loads approaching 50 percent of rated capacity at high speeds, 10 to 20 lifts an hour, averaging 15 feet with not over 65 percent at rated capacity.

Class E (severe service) – for magnet, bucket, and magnet/bucket combination cranes used at scrap yards, cement mills, lumber mills, container handling, etc, requiring loads approaching capacity throughout its life, with 20 or more lifts an hour.

Class F (continuous severe service) – for specialty cranes that are custom designed to handle continuous loads that approach rated capacity under severe service conditions. These cranes are designed to perform critical tasks that affect a total production facility. Thus, these cranes must be designed for reliability and ease of maintenance.