When is your crane's major inspection due?
Use our free checker to estimate when your overhead or gantry crane needs its major inspection under AS 2550.3-2025. You'll need the commissioning date, the M class marked on the bridge, and a rough idea of how hard the crane works.
What is a major inspection?
AS 2550.3-2025 calls it a major assessment. It has two parts: a theoretical part that works out how much of the crane's design working period (DWP) has been used, and a practical part where all critical components and systems are physically inspected.
For bridge and gantry cranes, a major assessment is needed when:
the DWP assessment shows a design limit will be reached before the next periodic inspection
a periodic inspection recommends one
defects become noticeably more frequent, or an inspection finds significant deterioration
a previous major assessment report says it is due
the crane is recommissioned or repurposed
a second-hand crane with no history is put into use (before it is used)
Design life is generally 25 years for the structure and 10 years for mechanisms, unless the manufacturer specifies otherwise.
Overhaul or replace?
Different parts of a crane reach the end of their life at different rates. At the major assessment, the competent person identifies the components that have reached their design life, and these are refurbished or replaced. If the hoist still has design hours left, an overhaul is usually the economical choice. If its hours are used up and most components are worn, a new hoist is often the better value.
Hoist design hours by M class
Every hoist has an M class (M1 to M8), marked on the bridge with the crane class (C on older cranes, A on newer ones). European hoists may also quote the matching FEM class. AS 2550.3-2025 Table 15.8.3 converts the M class into design operating hours at full load: M1 100 h, M2 200 h, M3 400 h, M4 800 h, M5 1,600 h, M6 3,200 h, M7 6,300 h, M8 12,500 h.
How the checker works it out
Hoist DWP: hours a day under load × days a week × 52 weeks × load spectrum factor × duty factor, compared with the design hours for the M class (AS 2550.3-2025 cl 15.8.3).
Load spectrum: average load ÷ capacity, rounded up to the next state of loading, L1 to L4 (Km 0.125, 0.25, 0.50 or 1.00). Rounding up keeps the estimate on the safe side, because a single average understates the effect of the heavier lifts.
Duty factor: how well usage is recorded (Table 15.4.2). Load recorder 1.0, counter or hour meter with records 1.1, production records 1.2, best guess 1.3, unknown 1.5. Better records give a later, more reliable date.
The date shown is the earlier of the hoist DWP and the 10-year mechanism design life.
Class unknown: 10 years divided by the duty factor. This is a planning estimate only.
Previous major done: the date of that major plus the interval set in its report.
The checker covers the hoist mechanism only. A major assessment also covers the structure, other mechanisms, electrics and controls.
Crane Inspectors carries out major inspections on overhead and gantry cranes across the Perth metro area. Call 0467 768 883.