Full Story – Competition Harness Life Extension
In 1998 the FIA introduced Standards 8853/98 and 8854/98, “FIA Safety Harnesses Standard”, which required that under “General Specifications”, the validity of a harness expires five years after the year of manufacture.
CAMS followed shortly after and incorporated the new FIA standards in the CAMS Manual for the year 2000.
The Australian Institute for Motor Sport Safety (AIMSS) established that there was no basis on scientific grounds for the applied 5 year limit as the effective life of a competition restraint harness. In order to investigate whether this was an appropriate figure for the validity period, AIMSS undertook the testing of used harnesses, varying in age up to 20 years.
If the research findings were to indicate that a longer life than five years could be safely permitted, this would ease a significant financial burden on competitors in events that did not have international status (where compliance with FIA regulations is mandated), especially in regard to amateur and club-level competitors.
As part of the study AIMSS had noted that similar questions in regard to road vehicles had been raised as long as 35 years ago. Investigations by several authorities uncovered no significantly increased risk of polyester webbing failure with increasing vehicle age, at least up to 17 years. No authorities are known to have imposed age limits on seat belt assemblies for passenger cars.
To conduct the testing AIMSS contracted Autoliv, a major FIA-approved crash and equipment test laboratory based in Melbourne, to examine and test two batches of race harnesses that were “out of date”; that is, beyond the five-year expiry date on the labels borne by the harnesses. A few old but undated harnesses, not made to FIA standards, were also included in the first test batch. Tests were conducted in accordance with FIA requirements for component strength, adjustment slip and buckle release force.
The testing was performed in two sample batches. The first batch of nine harnesses included several harnesses of an advanced age, two that had been in compliance with FIA 8853/98, the others a mix of older FIA requirements, SFI Specification 16.1, and long-superseded Australian Standard. The second batch of seven included harnesses of more recent manufacture but the validity of which had expired. All the harnesses were carefully inspected for signs of wear, corrosion and other signs of possible degradation.
It should be noted that Harnesses tested over 15 years old are unlikely to be in full compliance with the requirements of FIA Standard 8853/98, as these harnesses were originally built in accordance with the requirements of their periods, which were much less stringent. Even so, it will be seen that even the worst of the harness tested in terms of tensile strength would still sustain the loading of a mass of over 800 kg (single shoulder belt).
The following graphs show the results of the harnesses as tested for tensile strength. The first graph includes harnesses from both batches, the second graph, showing results for younger harnesses, previously FIA compliant before their expiry date.
Figure 1 includes all the harness components tested. Unsurprisingly, there is a downwards trend because it included some very old and well soiled belts that were never built to the current FIA standard.
Figure 2 depicts the results only for this ‘younger’, previously FIA-compliant group, showing the trend is level or even upwards.
This study established that while some of the older harnesses (non current FIA compliant) failed under a load less than the required minimum of 1,470 daN (14.7 kiloNewtons), none of the younger previously FIA-compliant harnesses aged up to 11 years did so. The average force at failure for this group was over 18 kN. Further, there was no indication of a trend towards deterioration in strength over time.
As a result, a recommendation was made by AIMSS to CAMS that the period of validity for harnesses in Australian in non-International competition could safely be extended from five to ten years, for FIA standard harnesses. The recommendation was adopted and implemented into the CAMS Manual of Motor Sport.