All high-quality leaf chain is manufactured to consistently tight tolerances.
Leaf chain is deemed to be worn beyond its safe service life when the nominal pitch length has been extended by 2% to 3%. At this point the fatigue life of the leaf chain is reduced and the ultimate breaking strength is considerably lower.
A leaf chain that is elongated by 2% is becoming dangerous and the competent person must determine a safe time limit for replacement.
A leaf chain that is elongated by 3% must be renewed immediately. Until the leaf chain is renewed, the equipment to which it is fitted must not be used.
It is recommended that wherever possible the leaf chain should be cleaned and measured in situ with the leaf chains placed under load.
The recommended load equates to approximately 1% of the minimum breaking load of the leaf chain.
Without the availability of a set of check weights it is, for the purpose of putting the leaf chain under load, normally sufficient to allow the leaf chains to be tensioned by the weight of the carriage and forks.