Risk of vehicles falling off two-post vehicle lifts in motor vehicle repair (MVR)
This Sector Information Minute (SIM) updates and replaces SIM 03/2005/05 and supplements SIM 03/2008/12. It alerts Enforcing Authorities to the risks of vehicles falling from 2-post lifts in motor vehicle repair facilities and outlines the key safeguards to safe operation. It explains action that has already been taken by the industry and some emerging issues that visiting staff may wish to be aware of.
Vehicle lifts are used throughout the motor vehicle repair (MVR) industry, including tyre and exhaust fitting centres. Two-post lifts have gained popularity over the last 20 years (they now outsell more traditional four-post lifts by over 3 to 1) at least in part because they have become available at increasingly lower cost.
Two-post lifts were originally used mainly for inspection and routine servicing (oil, tyre and exhaust changes etc), but are now commonly used for major work activities (though four-post lifts are still required for MOT testing).
SIM 03/2005/05 alerted inspectors to the risk of vehicles falling from two-post lifts where arm locking systems (required on new lifts since 1983) were either not fitted or were defective. It provided SG and Sector support from 1 January 2007 for the prohibition of two-post lifts that were not fitted with arm locking systems. With the co-operation of the Safety Assessment Federation (SAFed) and the Independent National Inspection and Testing Association (INITA), whose members carry out the vast majority of the 6-monthly thorough examination and tests on vehicle lifts in MVR, we believe that almost all lifts without arm locking systems have now been upgraded or removed from use.
SIM 03/2008/12 describes defective locking devices found on modern two-post lifts and the remedial action agreed with one known supplier. However, vehicle lift examiners are continuing to report concerns about the risks of vehicles falling from two-post machines including from some which have been newly installed. The Sector is aware of a number of occasions in the last five years where vehicles have fallen from raised lifts, mostly resulting in vehicle damage, but some involving serious injuries and at least two fatalities in the UK. It is the Sector view that whenever a vehicle falls from an elevated lift there is a risk of serious or fatal injury.
This SIM describes the key issues for the safe use and maintenance of two-post lifts. The contents have been discussed and agreed with SAFed, INITA and the Garage Equipment Association (GEA, who represent lift suppliers and manufacturers).
Configuration of two-post lifts
Two-post vehicle lifts typically comprise two upright columns - a master or powered column plus an auxiliary or slave. Some columns are connected by a structural overhead beam, which helps keep the columns rigid under load (not to be confused with light-weight cable trays, which do not).
Various configurations are available:
- Originally, most lifts had the columns squarely facing each other with front and rear arms of equal length. Vans, trucks, 4x4s and rear-wheel drive vehicles typically have their centre of gravity near the centre of the vehicle, so the most even weight distribution is achieved when the mid-point of the vehicle is aligned with the columns. Unfortunately, this makes opening car doors difficult (trucks and vans have their doors further forward). This is often known as a symmetric lift but symmetry can also refer to: the relative positions of the columns; the lifting arms; and the positioning of the vehicle's mid-point in relation to the columns.
- Since two-post lifts were introduced, front-wheel drive vehicles have come to dominate the market. However, their centre of gravity is not the mid-point of the vehicle but around the dashboard. To take account of this, lifts are now often manufactured with the front arms shorter than the rear arms (sometimes known as asymmetric arms or semi-asymmetric lift), so that the centre of gravity of the front-wheel drive vehicle can be placed approximately between the columns. The mid-point of the vehicle will then be behind the columns and provide better door access. A further development is to rotate the columns up to 30 degrees to make door opening even easier (sometimes referred to as asymmetric columns or as a truly asymmetric lift).
Each column is fitted with a pair of carrying arms that are pivoted at the column and of adjustable length (usually by telescopic means). This provides some flexibility when positioning the vehicle on the lift and may allow, for example, a van to be lifted on an asymmetric lift.
At the free end of each carrying arm there is a height-adjustable pick-up plate fitted with a rubber mounting pad. A two-post lift achieves 'wheel-free lifting' by aligning the pick-up plates to four jacking points on the underside of the vehicle body. This improves accessibility for certain tasks, for example, taking the gearbox and/or engine out of most front-wheel drive cars requires the removal of the front drive shafts, wheels etc to drop the unit out from below. This would be much more difficult to do on 4-post lift.
A typical two-post pick-up pad is between 100 and 125 mm diameter (4" to 5"), so adjustment and placement of the pick-up plates and mounting pads is critical to ensure the elevated vehicle is properly supported and stable. Accessories (eg low ground clearance skirts), or vehicle configuration (vans, 4x4s etc) may make it difficult to place the pads on the designated points. Adaptations need to be mechanically sound and securely fixed and manufacturers supply a variety of pad extensions for this purpose (see photo 1): blocks of wood are most unlikely to satisfy both criteria. Stability of the elevated vehicle can be affected if the rubber pad is worn, missing or contaminated by oil or grease. Adjustable screw threads are also subject to wear and damage. Where fitted, they should be self-braking and prevented from unscrewing (eg fitted with a circlip or similar).
Photograph 1 showing van supported on a symmetric two-post lift
A four-post lift differs in that the weight of the vehicle is spread via the contact surface of each tyre along the two fixed platforms so precise positioning of the vehicle on the ramp is not critical. A four-post lift provides a stable base that is more resistant to lateral movement and changes in load (eg removing heavy items such as gearboxes, engines etc).
Photograph 2 showing vehicle supported on 4-post lift
Safe installation of two-post lifts
Two post lifts rely on the ground fixing bolts for stability so it is essential that both the floor and fixings are of adequate strength. The manufacturer will normally specify what these should be. If the floor is of unknown specification, specialist advice may be required before installation eg from the lift supplier or specialist garage equipment maintenance company. Once installed, fixing bolts should be routinely checked to ensure they remain correctly torqued.
Safe operation of two-post lifts
The operator must position the vehicle carefully, taking account of its type (front-wheel drive, van etc), any additional load carried and the configuration of the lift (see above). Failure to do so may place the centre of gravity of the vehicle away from the columns giving an uneven weight distribution. The horizontal and vertical position of the pick-up plates then need to be adjusted, to ensure they will make full contact with the jacking points and support the vehicle securely. It is good practice to partially raise the vehicle (about a metre off the ground) and, by observation and rocking the vehicle, check that:
- the pads are correctly located;
- the vehicle is not being accidently supported on the lifting arms instead of the lifting pads;
- the arm-locking system has engaged fully on both sets of arms;
- the vehicle is stable; and
- the vehicle is being lifted parallel to the ground.
Even if a vehicle is properly supported on the pads, removal of heavy items once the vehicle is elevated may significantly alter the centre of gravity and individual pad loading. If the force exerted on any individual pad becomes too great or too light, and there is any free play in the arms or the arm-locking mechanism, the pad may either be 'squeezed' out or else be free to move horizontally. Where the movement is sufficient, the vehicle will no longer be fully supported (and is, essentially, balanced on just two or three of the pads). Any subsequent vertical load (eg torque generated by the use of tool) could cause the vehicle to fall from the lift. Consequently, operators should continually evaluate the need for additional supports (eg vehicle props) particularly where the combination of lift configuration and vehicle type is not ideal or where heavy items are to be removed from the raised vehicle.
To help ensure that vehicles are securely supported GEA issued the following safety advice in December 2009, following consultation with HSE and SAFed:
- Lift operators must be properly trained and be made aware of all risks. Over recent years motor vehicles have grown larger, particularly 4-wheel drive variants and correct positioning of the vehicle on the lift is essential. Always follow the vehicle manufacturer's guidelines and if lifting on the vehicle body or chassis (wheel free) always use the vehicle manufacturer's recommended lifting points. Where a limited number of models are lifted, it may assist operators if positioning marks (eg for parking the vehicle) are made on the floor. Lifting pads must be positioned carefully and adjusted for height if necessary. Simply kicking them into place and hoping for the best is reckless.
- It is important that the load is evenly distributed across all of the lifting points. Normally this will be achieved by using the vehicle manufacturer's recommended lifting points and this should be sufficient for general servicing work and inspection. However, the centre of gravity can alter significantly if heavy components (gear box, engine etc) are removed. Such work should preferably be carried out using a 4-post lift, but if a 2-post lift has to be used, it would be sensible to use supplementary vehicle stands to support the raised vehicle.
- 2-post vehicle lifts are equipped with arm locking devices; it's essential that these devices are engaged when the vehicle is raised. Therefore operators should always check that the arm locks are maintained properly, show no signs of damage or deterioration to their locking teeth and become engaged properly during use. Check that the restraint gears are fully engaged - If the gears have not fully engaged, lower the vehicle and gently move the arms forward and back until the gears fully lock into place. Never be tempted to deactivate safety devices – they are there for good reason.
- Lifting pads must be in good condition, appropriate for the vehicle being lifted, and kept clean from oil and grease. A damaged or contaminated pad may allow the arm to move under pressure, thus allowing the vehicle being lifted to fall off the lift.
- May we also remind owners of their maintenance and inspection responsibility under the PUWER and LOLER Regulations - Vehicle lifts should be regularly serviced (maintained) by a competent engineer and undergo a thorough examination by a competent person every 6-months. Thorough examination is in addition to, not a substitute for, regular inspection and on-going maintenance.
The Sector fully endorses the GEA 'safety alert' guidance.
Note - GEA have also published in 2011 a new booklet 'Safe Operation of Vehicle Lifts' which covers issues such as purchasing, installation, training, and safety in use. This is available from www.gea.co.uk free to download.
HSL test results
Vehicle lifts, including two-post lifts should be designed and manufactured in accordance with EN 1493:1999 'Vehicle Lifts'. Since the GEA advice was issued, HSL have carried out tests on one vehicle lift which was involved in a near miss incident when a vehicle fell from it. They applied horizontal loads to locked arms to check compliance with EN 1493 Section 5.8.5, which requires that arm-locking systems are designed to resist a force of 4.5 % of the capacity of the lift without permanent deformation, or to resist a force of 6.75 % of the capacity without breakage. The tests revealed that if the arm locking gears were only 75% engaged (eg 15 mm over 20 mm depth) there was a dramatic reduction in the load required to cause failure (from about 230kg to 50kg).
A horizontal load of 50 kg could easily be applied by a person working on the vehicle (eg using a tool to remove a tight bolt) and the weight of the vehicle can also induce a horizontal load if a support pad is not perpendicular to the jacking point.
Although there have only been a limited number of HSL tests to date, they indicate that full engagement of arm locking gears is crucial.
Free play in new two-post lifts
Section 5.8.5 of EN1493 also requires the step increment on arm-locking devices to result in movement of the pick-up pad at the end of a fully extended arm to be no more than one pad diameter. Using the same concept, SAFed have instructed their inspectors that, when the locking mechanism is fully engaged, any free movement at the pad end of the fully extended arm should not exceed one pad diameter, as this presents a risk of the vehicle being displaced. On the report of thorough examination SAFed Inspectors are categorising such movement as a defect where there is a risk of serious personal injury (ie requires action before further use and notification to the enforcing authority).
Free play exceeding one pad diameter has subsequently been found by SAFed inspectors in a number of lifts and satisfactory remedial action has been undertaken by the users. However, one manufacturer has objected to the SAFed defect classification criteria after locked-arm free play exceed the pad diameter on a two-post lift that they had recently supplied/installed. The manufacturer is adamant that their lift is safe and meets the requirements of EN1493. Inspectors should refer any enquiries relating to excessive free play to Principal Specialist Mechanical Inspector, who holds the portfolio for lifting equipment.
Revised EN 1493:2010
EN 1493 was revised in 2010 although HSE had no part in the revision process. The 2010 version has not been revised on the issue of free play which is still not part of the Standard. The section referred to above (5.8.5) has a new section number of 5.9.5 and has minor amendments. It adds a requirement 'It shall not be possible to fix the arm locks in a disengaged condition above 300mm of travel.'
Action by Inspectors
Where opportunities arise users of two post lifts should be reminded of the requirements for their safe use and maintenance. The information booklet issued by GEA is a helpful and succinct summary.
It would be helpful if inspectors would send details of any serious defects identified with two-post lifts and particularly incidents involving falling vehicles to the Manufacturing Sector
HSG 261 Health and safety in Motor Vehicle Repair and Associated Industries published October 2009 (which can be downloaded for free) gives advice on safe working beneath vehicles.
British Standard BS7980:2003 'Vehicle lifts —Installation, maintenance, thorough examination and safe use — Code of practice' was written in consultation with HSE and is used as a reference work by lift examiners.
If Inspectors require further information or technical support concerning this issue, they should contact their local Specialist Group (SG) in the first instance, LA EHOs through their Enforcement Liaison Officer (ELO). Additional advice can be obtained from the Manufacturing Sector.