The main aim to the regulations is to ensure safety, this is covered comprehensively by L.O.L.E.R. / FMVSS 404
In essence a competent engineer will be qualified to carry out a thorough examination of the lift.
To determine the extent of the thorough examination, the competent person will assess the risks, considering factors such as where the lift will be used, frequency of use, age and condition, the weight of loads to be lifted, etc.
A thorough examination may include some testing, if the competent person considers it to be necessary. The competent person will normally determine what tests are required, taking account of the relevant guidance and standards of the product manufacturer, and duty holders are recommended to insist on this approach.
Thorough examination may also be supplemented by inspection. Inspections should be carried out at suitable intervals between thorough examinations and may be done ‘in-house’ or ‘on-site’ by a competent, trained employee. Inspections would normally include visual and functional checks, eg that the safety interlocks operate correctly and lift pump pressure is in the correct range.
Thorough examination should not be confused with preventive maintenance, although they have some elements in common. Preventive maintenance usually involves replacing worn or damaged parts, topping up fluid levels and making routine adjustments to ensure risks are avoided. Thorough examination may act as a check that maintenance is being carried out properly, but is not intended to replace it.