Hoist Duty Service Classification 

Hoist Class Service Class Typical Areas of Application
H1 Infrequent or Standby Powerhouse and Utilities.  Infrequent handling.  hoists used primarily to install and service heavy equipment, where loads frequently approach hoist capacity with periods of utilization being infrequent and widely scattered.
H2 LIGHT Light machine shop and fabricating industries and service and maintenance work, where loads and utilization are randomly distributed with capacity loads infrequently handled, and where total running time of equipment does not exceed 10-15% of the work period.
H3 STANDARD General Machine Shop, fabricating, assembly, storage and warehousing, where loads and utilization are randomly distributed with total running time of equipment not exceeding 15 - 25% of the work period. 
H4 HEAVY High volume handling in steel warehousing, machine shops, fabricating plants, mills and foundries. Manual or automatic cycling operations in heat treating and plating operations.  Total running time of equipment normally approaches 25 - 50% of work period, with loads at or near capacity frequently handled.
H5 SEVERE Bulk handling of material in combination with buckets, magnets, or other heavy attachments.  Equipment often cab operated.  Duty cycles approaching continuous operation are frequently necessary.  User must specify exact details of operation, including weight of attachments.