Earlier this year we published an article entitled “Do chain hoists expire after 10 years?” where we examined the question of the design life of the hoist, and how this is measured in hours in service, combined with state of loading, rather than as an arbitrary calendar period.
Following on from this earlier article, we’d like to look at how the relevant Australian and European Codes and Standards approach the question of determining when it is time to either retire a hoist from service or undertake a major overhaul and rebuild to allow it to return to service after its original design lifespan has expired. The codes/standards we will reference are:
- Australian – AS-2550.1-2011 Cranes, hoists and winches – Safe use Part 1: General requirements.
- European – FEM9.755 Measures for achieving safe working periods for motorised serial hoists.
Both of these documents rely on accounting the Full Load Hours of operation of the hoist to determine its remaining safe working life. A hoist with Classification of 1Bm (EU) or M3 (AU) has the following:
|
Hours |
Loading |
Load Description |
|
400 |
1 (Heavy) |
>75% WLL |
|
800 |
2 (Moderate) |
>50% WLL to 75% WLL |
|
1,600 |
3 (Light) |
>25% WLL to 50% WLL |
|
3,200 |
4 (Very Light) |
<=25% WLL |
When accounting the Full Load Hours, you use both the time in service and the loading, which allows you to calculate either a) 1 hour at Heavy load or b) 2 hours at Moderate load or c) 4 hours at Light load or d) 8 hours at Very Light load, as 1 Full Load Hour.
If you don’t know the state of loading, then you must use full load (Heavy) for your calculations.
Both the Euro and Australian codes/standards are based around a simple concept – that the design life of the hoist (in Full Load Hours) is known, and that the operator of the hoist knows how many Full Load Cycles the hoist has been subjected to. This permits the calculation of the remaining Design Working Period (PWD) in AS2550, or the Safe Working Period (SWP) in FEM9.755.
The Australian Standard (AS2550.1) has an entire chapter (Section 9 Major Assessment for Continued Use or Changed Operation) that describes the steps to be taken to determine the hoists suitability for continued safe use. These steps are significant, including a complete dismantling and rebuild of the hoist, with non-destructive testing (NDT) of structural components.
This must be carried after 2/3 of the original design life of the hoist (in Full Load Hours), or at 7 calendar years if the number of Full Load Hours in service is unknown. If your hoist is infrequently and/or lightly used, this could mean that 2/3 of the design life may be many years beyond 7 calendar years.
The European Code (FEM9.755) is similar in its approach – it requires that, at 10 calendar years from the date of first entering service, the hoist must undergo a Major Service, which includes inspection and replacement of wear items, such as brakes & clutch pads, chain (if elongated) and changing of gearbox oils and drive belts.
This should only be done if the hoist has a significant part of its original design life (in Full Load Hours) remaining. If the Full Load Hours are unknown, then the hoist must undergo a Major Rebuild, which entails dismantling, NDT of structure and replacement of major components.
For a motorised chain hoist, the cost of such a major assessment (to AS2550) or a Major Rebuild (to FEM9.755) would usually be more than the cost of replacing the hoist with a new unit.
You need to know how many Full Load Hours your hoist has been operated for, if you want to keep the hoist in service for as long as possible.
Keep Logbooks for your hoists and keep them up to date.
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