Some thoughts on Progressive Safety Gears and Modernisation

Where a lift has been subject to a modernisation programme, or, more particularly, one or more successive cab refurbishments, resulting in a change of car mass, it is essential that the continued integrity and compliance of the safety gear be confirmed before the lift is returned to service. In the European context, EN81-1: Annex D specifies a commissioning test with 125% rated load and travelling at rated speed or lower. This test does not check the free fall performance. It is simply a test to ensure that the safety gear has been installed correctly and is functional. Consequently, after a modification it is not sufficient simply to perform the confirmatory test specified in Annex D. However, there is no currently accepted method to establish free fall performance on the basis of a test with intact suspension. The objective of this paper is to discuss why that may be the case, and to explore possible ways in which, whilst it may not be possible to establish an accurate measure of free fall deceleration, nevertheless, it might be possible, in some circumstances, to establish with a reasonable degree of confidence, whether or not a given installation would have a free fall deceleration within the range required by EN81-1/EN81-2