30,000 kg Lorry Lift Modernisations – 70 Gracechurch Street, London
Originally installed by Otis in 2000. This project involved modernising two lorry lifts. Each had a rated load of 30,000 kg or 400 persons, speed 0.15 m/s, serving levels B2 and G (first lift) and levels B2, B1 and ground (second lift). With a car width 3925, depth 12500, height 4500mm.
The lifts were used to transport lorries between street and basement service bay level to service a very busy M&S store in the heart of the City of London.
The lifts had reached the end of their life expectancy, were proving unreliable and fell short of current health and safety requirements.
The work involved full modernisation to re-fresh the life of the lifts and bring them up to current health and safety standards.
This was a turnkey project with the lift contractor undertaking the lift and all associated works. Following a pre-qualification exercise to identify suitable contractors, the work was bid to five contractors base on a detailed performance-based specification produced by The Lift Consultancy. Focus Lifts were the successful contractor with the preferred compliant bid based on value and technical reassurances. The work was then procured under an MF 1 contractor with The Lift Consultancy acting in the Contract Administrator role, Principal Designer role as well as undertaking full consultancy duties for the project.
After 20 years of heavy use the lift cars were showing signs of their age and usage. Bump rails and walls were heavily damaged from vehicle impact. The central flooring was deformed and lifting, switches and sensors were damaged/inoperative and the traffic lights in the lift cars remain permanently on red! The original doors and especially the locking mechanism were problematical due to the excessive movement as the heavy vehicles departed the platforms.
Particularly unusual was the method for accessing the car top. This was via scaffolding that was kept within the lift car. A potential safety hazard if the associated risk assessment was not available to the person(s) wanting to access the car top.
The lift car whilst damaged was substantially sound. The work involved re-conditioning the interior, replacing any heavily damaged floor panels, de-rusting and cleaning, new bump rails and re-painting.
A safer means of accessing the car top was provided and the lift design included the provision for PAWL devices that would lock the lift at floor level. if the stronger replacement entrances required the additional stability. At the testing phase it was decided that this provision was not required as the correctly specified replacement entrances were robust and able to work satisfactorily with the new reduced platform movement.
The controllers were in a poor state with a jungle of wiring having been added/altered over the years. Some of the wiring modifications had been drawn on the inside of the control panel door! Along with good luck messages for the next unfortunate repair engineer!
With no updated wiring diagrams available to reflect all the modifications, fault-finding at times was extremely difficult.
The log cards reported numerous electrical failures (along with door failures) with frequent blown fuses and a fire inside the shaft originating from the shaft lighting.
The control panels were replaced with modern technology including variable voltage variable frequency drive units. These were third party New Lift control panels.
Each lift employed multiple tank units to drive the bore hole rams. As a back-up measure, the tank units were duplicated so four per lift, eight in total for the two lifts. The main tank units were replaced with the motors being driven by more energy efficient VVVF drives. The control panel was designed with built in redundancy features and protective filters added to the hydraulic system. In the event of a power unit failure, it is possible to isolate the faulty unit and drive the lift (slower) using the remaining units. This is a feature ensuring essential vehicles and stock can continue to their next destination.
The main tank units were replaced with the motors being driven by more energy efficient VVVF drives.
The bore hole rams were retained after the being subject to camera survey and following CCTV and Safed inspections that included pressure testing.
The doors were heavily damaged due to impact damage by lorries and modified to attempt to improve reliability. Numerous sensors offering driver information were inoperative. Door edges inoperative or very slow to operate but the main issue was the drivers would depart the lift when the doors were higher than the cabs but unfortunately lower than the trailer! The specification included fast internal car gates which resulted in the lorries remaining stationary until it was clear to leave.
The doors were completely replaced with ones of a more robust design from Peelle. Numerous spare parts were also kept on site within locked cabinets.
