CMAACMAA Class Description Details

A Standby or Infrequent service

This class normally includes installation and maintenance cranes. This equipment usually operates at slow speeds for precise handling with long idle periods between lifts. Maximum capacity lifts are sometimes required.

B Light Service

This class of crane is used in repair shops, light assembly operations, service buildings, light warehousing, etc. Service requirement is light and speeds are slow. Loads vary from none to occasional full capacity. Lifts per hour would range from 2 to 5, and average 10 feet per lift.

C Moderate Service

In terms of numbers, most cranes are built to meet Class C service requirements. This service covers cranes that may be used in machine shops or papermill machine rooms. In this type of service, the crane will handle loads that average 50% of the rated capacity with 5 to 10 lifts per hour averaging 15 feet. Not over 50% of the loads at rated capacity.

D Heavy Service

This service covers cranes which may be used in heavy machine shops, foundries, fabricating plants, steel warehouses, container yards, lumbermills, etc., and standard duty bucket and magnet operations where heavy duty production is required. In this type of service, loads approaching 50 percent of the rated capacity will be handled constantly during the working period. High speeds are desirable for this type of service with 10 to 20 lifts per hour averaging 15 feet, not over 65 percent of the lifts at rated capacity.

E Severe Service

This type of service is reserved for top riding bridge and gantry type multiple girder electric overhead travelling cranes and requires a crane capable of handling loads approaching rated capacity throughout its life. Applications may include magnet, bucket, magnet/bucket combination cranes for scrap yards, cement mills, lumber mills, fertilizer plants, container handling, etc., with 20 or more lifts per hour at or near the rated capacity.

F Continuous Severe Service

This type of service is reserved for top riding bridge and gantry type multiple girder electric overhead travelling cranes and requires a crane capable of

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handling loads approaching rated capacity throughout its life. Applications may include custom designed specialty cranes essential to performing the critical work tasks affecting the total production facility. These cranes must provide the highest reliability, with special attention to ease of maintenance features.

HMI

Class

Operating Based on 65% of Capacity

DetailsUniform Usage Infrequent UsageMax On Time (min/hour)

Max Starts/Hour

Max on Time From Cold Start

Max Starts

H1 7.5 minutes (12.5%) 75 15 100

Powerhouse and Utilities, infrequent handling, Hoists used primarily to install and service heavy equipment, loads frequently approach capacity and hoist idle for long periods between use.

H2 7.5 (12.5%) 75 15 100Light machine shop fabricating, service and maintenance; loads and utilization randomly distributed; rated loads infrequently handled. Total running time not over 12.5% of the work period.

H3 15 (25%) 150 30 200General machine shop fabricating, assembly, storage, and warehousing; loads and utilization randomly distributed. Total running time not over 25% of work period.

H4 30 (50%) 300 30 300

High volume handling of heavy loads, frequently near rated load in steel warehousing, machine and fabricating shops, mills, and foundries, with total running time not over 50% of the work period. Manual or automatic cycling operations of lighter loads with rated loads infrequently handledsuch as in heat treating or plating operations, with total running time frequently 50% odf the work period

H5 60 (100%) 600 N/A N/A

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.

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FEMSelect the Appropriate Load Spectrum

Calculate the Average Daily Operating Timet = ( 2 x H x N x T) / (V x 60) Where:H = average hoisting height (m or feet)N = number of work cycles per hour (cycle/hour)T = daily working time (h)V = hoisting speed (m/min or feet/min)

Determine the Operating Group of the Hoist

Load Spectrum Average Daily Operating Time (hours / day)

<= 0.5 <= 1 <= 2 <=4 <= 8 <= 16Light M3

1BmM4 1Am

M5 2m

M6 3m

Medium M3 1Bm

M4 1Am

M5 2m

M6 3m

M7 4m

Heavy M3 1Bm

M4 1Am

M5 2m

M6 3m

M7 4m

Very Heavy M4 1Am

M5 2m

M6 3m

M7 4m

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