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How to Understand the Service Life and Working Level of Cranes Under Different Standards?

Sep 22, 2025

Using Class

The design life of a crane refers to the total number of working cycles a crane can complete from the start of its service life to its final decommissioning.

A working cycle is defined as the complete process from the lifting of one load to the start of lifting the next load, which includes the crane's operational processes and normal energy downtime.

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Load Spectrum

Load Spectrum indicates the extent of which the mechanism is subjected to maximum stresses (full capacity lifts) or whether it is subject to smaller loads only.

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Load Level	Kp	USING CLASS(GB/T3811-2008)
Load Level	Kp	U0	U1	U2	U3	U4	U5	U6	U7	U8	U9
L1	Kp≤0.125	A1	A1	A1	A2	A3	A4	A5	A6	A7	A8
L2	0.125	A1	A1	A2	A3	A4	A5	A6	A7	A8	A9
L3	0.25	A1	A2	A3	A4	A5	A6	A7	A8	A8	A8
L4	0.5	A2	A3	A4	A5	A6	A7	A8	A8	A8	A8

Using Class	WORKING Cycle (l)	Description
U₀	L≤16000	Hardly Used
U₁	16000	Hardly Used
U₂	32000	Hardly Used
U₃	63000	Hardly Used
U₄	125000	Infrequently Used
U₅	250000	Moderately Used
U₆	5000000	More Frequently Used
U₇	10000	Frequently Used
U₈	20000	Extremely Frequently Used
U₆	5000000	More Frequently Used
U9	L≥ 40000	More Frequently Used