rusty corroded leaf chain link that fails to articulateEnvironments in which materials handling forklift truck chain and leaf chain mechanisms operate can vary widely, from normal outdoor moisture to mildly corrosive or highly corrosive industrial atmospheres. In addition to abrasive exposures, such as sand and grit, some of the effects on forklift truck chains and leaf chains can be as follows:

Moisture - Corrosive rusting which reduces the leaf chain strength by pitting and cracking.

Temperature - Low temperature reduces forklift truck chain strength by embrittlement. Constant going in and out of cold store results in moisture from condensation which forms on the outside and bearing surfaces of leaf chain. This negative effect causes stiffness and ultimately corrosion fatigue cracking which leads to early replacement of forklift truck leaf chain.

Chemical solutions or vapours - Corrosive attack on leaf chain components and/ or leaf chain anchor pins, leaf chain anchor bolts and leaf chain anchor blocks causes stress corrosion cracking. This cracking can be, and more often than not is, microscopic. Dependant on exposure, microscopic cracks will propagate across the forklift truck chain/ leaf chain and will rapidly lead to a complete and abrupt failure.

Abrasives - Accelerated wearing or scoring of the articulating members of leaf chain (pins and linkplates) lead to a corresponding reduction in forklift chain strength.  Due to the inaccessibility of the bearing surfaces of leaf chain (pin surfaces and linkplate apertures) the wear and scoring are not readily noticeable to the naked eye.  Consequently forklift truck chain wear should be constantly monitored using the FB Chain professional chain wear gauge (CWG).

Conclusion - Each specific forklift truck chain application should be evaluated for risk based on the degree of exposure to the above and assessment of the specific area of operation.  A leaf chain replacement schedule should be established to prevent any possibility of forklift truck chain failure.  This schedule can be established by the frequent inspection of leaf chains.  Based on these observations the frequency of forklift truck chain inspections can be altered, noting however, that due regard must be paid to the legal minimum requirements as set out in LOLER 98, regulations 9, 10 and 11, for the Thorough Examination and Inspection of Industrial truck leaf chain.  At the same time it would be prudent to familiarise oneself with all the relevant Health and Safety guidance notes and particularly PUWER 98.  Others guidance documents are published by the British Industrial Truck Association (BITA GN15 & GN28) and the technical bulletins of Fork Lift Truck Association (FLTA TB 02, 05, 08 & 09).  Inspection procedure development for leaf chain should proceed until a projected time of replacement can be predicted.  A forklift truck leaf chain by its very nature should be considered an expendable item and a safe leaf chain replacement schedule established.

It is further recommended that forklift truck chains used in arduous, harsh or aggressive environments such as cold stores, marine, corrosive chemical, metal manufacturing or processing, cement/ aggregate processing and brine processes (this list is not exhaustive) should have their leaf chains and leaf chain anchor pins replaced after a period not exceeding 4000 operating hours or two years, whichever is the shorter.  Additionally where the lifting mechanism uses a single leaf chain (eg. free lift section), any leaf chain anchor bolts should also be replaced at the same time.