The Work Duty Classification of the Overhead Cranes between European Standard FEM 、International Standard ISO and China National Standard GB.

1. Cranes Work duty Classification

Work Duty				Intermittent Service
State of loading	FEM	ISO	GB	Cycles/H	Start/H	Ed in %
Light	1DM	M1	A1	15	90	15
	1CM	M2	A2	20	120	20
Moderate	1BM	M3	A3	25	150	25
	1AM	M4	A4	30	180	30
Heavy	2M	M5	A5	40	240	40
	3M	M6	A6	50	300	50
Super Heavy	4M	M7	A7	60	360	60
	5M	M8	A8	60	360	60

  

2. Determining the Operating Group of the Hoist

According to the Average daily operating time to separate the lifting mechanism work duty:

Work Duty	Average daily operating time (hours per day)
	≤0.5	≤ 1	≤ 2	≤ 4	≤ 8	≤ 16
Light duty			M3	M4	M5	M6
Moderate		M3	M4	M4	M6	M7
Heavy	M3	M4	M5	M6	M7
Super heavy	M4	M5	M6	M7

  

How to calculate the Average daily operating time ?

The average daily operating time of the hoist can be calculated from the running time of the hoisting machinery (hours per day):

t =  (2 × H ×N × T) ÷ (V × 60)

T:Average Daily Operating time.

H:Average lifting height (meter)

N:Number of Work Cycles Per Hour (cycles/h)

T:Daily working time (h)

V:Lifting Speed (m/min)

3. Work duty Classification

Light Duty:  Mechanism subjected very rarely to the maximum load and normally, to light loads.

Widely used in the power plant and areas where mainly use to installation and maintenance the machines, or the not busy workshop.

Moderate Duty: Mechanism subjected fairly frequently to the maximum load but, normally, to rather moderate loads.

Widely used in the busy work shop, like the normal machinery processing and assembly line etc.

Heavy Duty:  Mechanisms subjected frequently to the maximum load and, normally, to loads of heavy magnitude, Widely used in the busy workshop, long times and frequently loading the heavy duty materials, steel plant etc.

Super Heavy Duty: Mechanisms subjected regularly to the maximum load, mainly used in the steel plant, casting plant etc.