The SEB SuperEndurance chain launched by FB Chain this year.

Proposed changes to ISO 4347 will require forklift leaf chain manufacturers to demonstrate that their products offer dynamic strength, or high levels of 'fatigue' resistance.

Chain suppliers that supply to original equipment manufacturers (OEMs) as well as forklift dealers are currently only required to demonstrate that their products comply with 'breaking load' guidelines.

A chain's 'breaking load' indicates the stress or force that can be applied to a chain before it breaks or ruptures.

By introducing an element of fatigue resistance testing to ISO 4347, the International Standards Committee will require that chains have good endurance levels as well as high breaking loads.

"A high breaking load alone does not indicate that a chain will have a long life," says Jim Cameron, technical director of FB Chain Ltd and a member of the international standards committee tasked with overhauling the current guidelines.

The proposed changes to ISO 4347 will require chain manufacturers to show that their chain will withstand a minimum dynamic load for at least three million cycles.

Cameron explains: "A chain's ability to provide good 'fatigue' resistance while maintaining high breaking loads is a far more accurate guide to the chain's quality and suitability.

"Most good chain manufacturers will know the fatigue limits of their products and engineers looking to design ... or replace a forklift chain should be taking fatigue limits into consideration as well as breaking loads.

"Anyone tasked with acquiring new leaf chain should ensure that what they are buying has been thoroughly tested for both 'breaking load' and 'fatigue resistance'."

The changes are expected to be adopted in the next 12 months.

ISO 4347 is the international standard governing the manufacture of the type of leaf chain used by forklift manufacturers to operate forklift masts.