Comments on BS EN 1570

Safety requirements for scissor lifting tables and scissor lift platforms. Scissor lift tables serving more than 2x fixed landings of a building, for lifting goods with a vertical travel speed not exceeding 0,15 m/s This European Standard deals with all significant hazards pertinent to scissor lifting platforms when they are used as intended by the operating instructions and under the conditions foreseen including foreseeable misuse with the operating instructions This European Standard specifies the appropriate technical measures to eliminate or reduce the risks arising from the significant hazards.

This is a summary of salient points relating to this standard, it is intended as a brief guide or
overview through some selected parts of the current Scissor Lift Table or Platform Lift standard. In the critical we concentrates on hydraulic scissor lift tables as they are the most common. 

Scope

BS EN 1570 specifies the safety requirements for scissor lift tables and scissor lifting platforms, powered or manually operated whether, stationary or mobile for raising and/or lowering goods and/or persons associated with the movement of goods carried by the lift table (i.e. not for passenger use), for a vertical travel of up to 3,0 m. It attempts to address all significant hazards applicable to platform lifts when used in foreseen situations and as intended by the manufacturer. EN1570 states many appropriate technical steps to eradicate or lessen risks stemming from these identified significant hazards.

Whilst EN 1570 does not cover all types of Lifting Tables, this does not mean that lifting tables cannot be designed and built to be suitable, safe and fit for another purpose and then certified appropriately. For instance, it is necessary to consider what must be done to a Scissor Lift Table if you wish to make it suitable for an unusual application. The designer shall also look to see if there are other applicable standards that may apply in eth chosen application.

When using lift tables for vehicle loading applications the specifier should also take into account

EN 1398 – The Dock Leveller Safety requirements.

Definitions

For the purposes of EN 1570 the following definitions apply:-

Lifting Table - load lifting device with a load supporting platform guided throughout its travel (e.g. guided by its own mechanism.)

Load Platform - the part of the lifting table designed to accommodate the working load and/or
persons. Fork arms are considered as a load platform for goods only

Vertical Travel - the vertical distance between the highest and the lowest working position for which the lifting table is designed

Nominal Load - the load that the manufacturer has guaranteed that the machine will lift when used in accordance with the instruction handbook. 

Guard - part of machine specifically used to provide protection by means of a physical barrier

Safe by Position - condition when a table or part of table is sufficiently shielded from access to
avoid any hazard to persons or goods Operator -Person who is trained to operate the lifting table safely according to the manufacturer’s instructions.

Travel Zone – space through which the lifting mechanism and load platform and any attachments moves.

Safety requirements

Machinery shall comply with the safety requirements and or protective measures of this clause and in addition be designed according to the principals of EN ISO 1200 for relevant but not significant hazards which are not dealt with by this standard.

The design shall include calculations of the loading's and the stresses. The permissible stresses shall not exceed 0.66 times the yield stress of the material used or 0.5 times the ultimate tensile stress of the material used. Dynamic forces are to be considered such as moving loads, forces applied to the mechanism as the load is positioned etc.

The Load.

Scissor Lift Tables shall be designed to take the rated load, when uniformally distributed over the full platform area with the load centre above the centre of the platform. If the load is not unformally distributed, then as a minimum the lift shall accommodate half the rated load distributed over half the platform length or one third of the rated load distributed over half the platform width. In neither case shall hazardous tilting or deflection take place when used as intended by the manufacturer.

Do remember that unevenly loaded lifts will probably show a measurable level of deflection especially if used towards the upper level of the rated safe working load. Consideration must be given to the different types of loading and unloading method for the platform for instance.
concentrated loads, point loads, rolling loads, single axle or wheel loads.

Safeguarding:- Crush, trap and shear

Generally crushing and shearing shall be avoided by the following minimum gaps between moving parts and between moving and fixed parts which are in reach by persons. 25mm. for fingers, 50mm. for toes, 100mm. for hands, 120mm. for feet, arms and closed hands and 500mm for the body.

Alternatively other safety measures shall be taken to avoid the operator or any other persons being endangered, e.g: barriers, deflectors, non-mechanically actuated trip devices complying with EN 50100, mechanically actuated trip devices complying with category 1 of EN 954-1, multiple controls requiring simultaneous operation or / and screens. In some applications individual examples will not be sufficient by themselves and should be used in conjunction with each other or other equivalent methods.

Clearances between components. Crushing and shearing shall be avoided by the following minimum gaps between moving parts and between moving and fixed parts:
30mm between the leg mechanism, cylinder etc and 50mm at the sides of the base frame and
platform. In particular applications, other safety measures shall be taken to avoid the operator or any other persons being endangered, this could include barriers, deflectors, non-mechanically actuated trip devices, mechanically actuated trip In scissor type lifts there are specified minimum safety gaps between the scissor arms. See Figure 1 in the Standard.

When lowering a minimum of free space for the feet shall be provided in accordance with Figure 2 in the Standard to prevent crushing and shearing of feet.

Where the machine is fully enclosed with an imperf orate rigid guard or is “safe by position” the minimum gaps are not necessary. If the machine is only partly enclosed by an imperf-orate rigid guard, then an acceptable alternative must be provided to guard the parts of the machine not enclosed. When a mechanically actuated trip device safety edge is fitted to the underside of the platform then it is necessary to maintain only the minimum gaps for fingers inside the area safeguarded by the device. These safety devices shall operate so that the moving part causing the hazard comes to a stop before injury is caused. They shall not create and additional hazard.

Where a mechanically actuated trip device (e.g. anti trap bar) is fitted to the underside of the
platform, the anti-trap device when actuated shall stop all downward movement of the platform and hold it stopped until the down control has been released, the obstruction removed, the device reset and the down control re-operated. It shall always be possible to raise the platform in order to clear the obstruction.

Where the lifting table serve fixed landings above 1.6m above the lowest landing in restricted areas may be provide with screen guarding in accordance with EN ISO 13857.

Lifting tables that are designed to be accessed by operators shall ne provides with guardrails means shall, as a minimum, consist of guard-rails at least 1,100mm high, toe-guards at 100mm high and intermediate guard-rails not further than 500 mm from either the guard-rail or toe-
guards.

Where gates or opening parts of the barrier are fitted, they shall be fully interlocked with the control system so that the platform can be moved only when the barrier is closed. Furthermore, outward opening parts shall be interlocked in such a way that these parts can only be opened when the platform is in a clearly defined access position.

Unless the scissor lifttable is designed to enable all maintenance work to be carried out when the platform is fully lowered on to mechanical depth stops, a manually operated blocking device or maintenance prop / safety locks, shall be fitted to all lifting tables to allow maintenance work to be carried out below the platform in safety. This device shall be capable of supporting the platform with its rated load, and of being operated from a safe position.

Lifting tables which operate in areas to which the public (especially small children) could reasonably be foreseen to have access, shall be enclosed by a rigid guard to prevent the hazard due to the descending platform. Alternatively, a semi-rigid guard (e.g. mesh or material) can be fitted in conjunction with a mechanically actuated trip device / perimeter anti trap bar.

Speed of Operation

The lifting and lowering speeds of the platform shall not exceed 150mm per second, except
where the platform is automatically programme controlled and “safe by position”.

Emergency lowering devices, where fitted, shall be of the ‘hold-to- run’ type. These devices shall be fitted in a safely accessible position and shall not be capable of unauthorized operation.

The operator’s position shall be such that the operator has clear view of the platform and its load at all times throughout its full travel.

All controls shall be of the hold-to- run (deadman) type and be designed to prevent unintentional operation. This does not apply to automatically controlled movements of the lifting table.

Where alternative controls are fitted in multiple locations they shall be wired so that only one set can be in use at any one time, excluding the emergency stops. Platform mounted controls must always have priority, when operated, over the off-platform positioned controls, excluding the emergency stops. If there is only a control position on the lift platform, there must be at least one additional emergency stop control not on the lift platform and in an easily accessible position.

Hydraulic system

A pressure relief valve shall be fitted in all hydraulic systems and shall be positioned and set so
that not more than 110 % of the maximum working pressure can be achieved. Where adjustable,
the adjustment of this valve shall require the use of tools. It shall be positioned so that it will not cause the platform to descend out of control if an overload is placed on the raised platform.

All hydraulic drives shall be equipped with an automatic fail-safe device to limit unintentional
lowering of the platform to a maximum of 100 mm and to stop the platform at any height, in case of rupture in the hydraulic hoses. This device shall be designed to carry 150 % of the rated load.

Marking

All lifting tables shall have a warning notice in letters at least 15 mm high

DO NOT ENTER UNDER THIS PLATFORM UNLESS ITY IS MECANICALLY LOCKED

Unless designed for carrying operators there shall be a notice prohibiting the carriage of
passengers. All lifting tables shall be marked with the following information on a single plate.

RATED LOAD AND DISTRIBUTION
DESIGNATION OF MACHINERY
MANUFACTURER BUSINESS NAME AND ADDRESS
SERIES OE TYPE
SERIAL NUMBER
IP CODE
YEAR OF CONSTRUCTION

Information for use -

The manufacturer shall supply with each lifting table a set of operating instructions as described in the Standard. The instructions must be sufficient for the safe operation of the lifting table and in the language of the Country that the lift is to be used in. Pictorial instructions will assist for whom English is not their first language.