The safe operation period of the lifting mechanism depends on whether it is used correctly according to the specific working level. According to the European Handling Association standard FEM9.511 and the relevant Chinese national standards, the working level of the hoisting mechanism of the crane is determined by the load spectrum and the average daily operating equivalent time.

Load Spectrum

 

Load spectrum

Light

Medium

Heavy

Very Heavy

Occasional full load
Usually light load
Small fixed load

Occasional full load
Usually light load
Average fixed load

Repetitive full load
Usually average load
Heavy fixed load

Usually almost full load
Very heavy fixed load

 

 

Average daily operating time

The average daily equivalent use time can be calculated according to the actual use time according to the statistical method. The reference formula is as follows:

t=(2 x N x H x T)/(V x 60)
H = average hoisting height (m)
N = number of work cycles per hour (cycles/h)
T = daily working time (h)

Determining the working level of the hoist

When the load spectrum and the average daily equivalent use time are determined, the work level can be found according to the data in the following table:

Load Spectrum Average daily operating time ISO(GB) / FEM (hours per day)
≤0.5 ≤1 ≤2 ≤4 ≤8 ≤16
Light     M3
1Bm		 M4
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		    

Example: The crane load spectrum of a user is Medium, the lifting speed V=5m/min, the average working height H=3m, the average working cycle N=5 times per hour, and the two-shift daily working time T=16 hours. We can calculate the equivalent working time is t=1.6, and the working level found from the above table is Chinese national standard M5 (equivalent to the European standard 2m).