Lift Report

The manufacturer is obliged to draw up an EC Declaration of Conformity for the landing door locking device and to equip the product with a CE mark. After discontinuation of production, the documents must be retained for at last 10 years.

DIN EN 81 Parts 1 and 2 describe the safety regulations for the design and installation of lifts. Under point 8, the landing doors are described. Their geometry, for instance, must not become deformed over time, and the authoritative fi re regulations applicable to the building must also be fulfilled. As regards the door leaf itself, a vertically applied force of 300 N spread evenly over an area of 5 cm² may not leave any lasting deformation whatsoever and only a maximum elastic deformation of 15 mm, and the safety function may not be in any way impaired during testing. When applying a manual force of 150 N on the most unfavourable point, in the case of doors opening on one side the gap may not exceed 30 mm, and in centrally opening doors 45 mm.

In the case of glass doors, additional requirements are imposed, in particular in respect of the quality and mounting of glass panes. These are listed dependent upon their dimension in Table J.2. A distinction is made in terms of glass pane fixture between two-sided (top and bottom), 3-sided (top, bottom and at the side) or four-sided fixture. Depending on the glass pane fixture, the glass type used must be laminated safety glass made of thermally pretensioned glass VSG-V or laminated safety glass made of fl oat glass. The glass thickness must always be 10 mm/16 mm respectively. Admissible widths for door leaves range from 300 mm to 870 mm with a maximum clear door height of 2100 mm. If deviations occur in landing doors from the version specified in the table in terms of the glass structure and dimension, special tests according to Annex J are prescribed. Pendulum impact tests are performed using a hard impact object weighing 10 kg and a soft impact object weighing 45 kg. The door leaves must be mounted for testing in a test rig which corresponds with their subsequent mounting situation. The impact point on the test specimen is one metre above finished height of floor in both cases. The hard test object is a steel bulb with a drop height of 500 mm, the soft object a leather sack fi lled with pieces of lead which is dropped from a height of 700 mm. The pendulum impact test is considered successfully passed if one impact each with the hard and the soft object are performed without damaging the door leaf.

This standard also demands protection against movement of the landing doors. The landing doors must be designed so as to minimize any possible hazard from trapping of body parts, clothing and objects. This is achieved by eliminating any kind of depressions or raised areas in excess of 3 mm. Should such depressions or raised areas still be present, they must be bevelled in the direction of opening. In order to prevent the doors from closing, the static clamping force may not exceed 150 N. The kinetic energy arising from the mass of the door leaf and the closing speed when the door closes must not exceed the value of 10 Joules. If a landing door makes contact with a person, or if such contact is possible, a protective device must be provided which causes the door to open again automatically.

As long as there is not an elevator car behind the landing door, it must always be locked. Precise limiting values exist for the resilience of the lock. The opening force, for instance, must be capable of withstanding a force of at least 1000 N in the case of sliding doors and of 3000 N in the case of hinged doors. As mentioned at the beginning of this article, the lock is considered to constitute a safety component and must consequently be subjected to a special test procedure in accordance with Annex F1. The lock monitoring system must be configured in the form of a safety circuit, and unlocking may only be permitted using a precisely defined triangular key.

However, regrettably DIN EN 81 Parts 1 and 2 treats all landing doors as identical, and consequently hardly any difference is drawn between landing doors with sheet metal door leaves in apartment blocks, landing doors with framed glass door panes used in local public transport applications, landing doors in exclusive hotels or office blocks or landing doors used industrially in a manufacturing context.

On closer inspection of the standard, however, a number of flaws come to light. As regards the service life of doors, with the exception of the locking device hardly any requirements are imposed. It has frequently been shown in the past in the case of sheet metal door leaves that the strength requirements are insufficient, in particular when it comes to withstanding vandalism. A number of accidents have demonstrated that the door guide at the bottom is frequently unable to cope under high levels of stress. In the case of glass doors, the glass type and glass surround are defined in table J 2, while there is no specification at all of the design and mounting of the door leaf. It has been shown in practice that door leaf designs in compliance with this table fail to withstand pendulum impact testing in accordance with Annex J. The strategy adopted by suppliers of landing doors is clearly transparent when completely modified component geometries are used in the case of glass doors which are not covered by the standard. The pendulum impact test in compliance with Annex J is without doubt a test which defines a certain degree of resistance. Regrettably, however, it demands only a single impact to be made each with a hard and a soft impact object. This begs the question of whether three impacts might not more effectively reflect actual events occurring in every application.

DIN EN 81 Parts 1 and 2 do not stipulate the mandatory use of any preventive protective devices which would prevent objects becoming jammed in the doors. It is perfectly possible while adhering to the admissible values for static clamping forces and kinetic closing energy for accidents to occur affecting users in hospitals, old people’s homes and nurseries.

The points listed above clearly reveal certain areas of uncertainty in respect of landing doors conforming to DIN EN 81 Parts 1 and 2. Consequently, correct operation of a lift in line with its intended purpose should be defined and documented right at the early planning stage. A key factor is to ensure clarity regarding the intended building type (residential complex, administrational building, care or nursing home ...) and to make a detailed study of the intended user group (children and adolescents, the disabled...). If bulky or heavy loads, or hazardous materials will have to be transported in the lift, this fact must also be taken into account in the design of the landing door. Environmental conditions such as damp, rain, snow or direct sunlight also have an additional impact on the equipment of the door. To simplify the process of coordination between component manufacturers and lift constructors or planners, the Lift and Escalator Association attached to the VDMA has drawn up a working paper entitled “Specified normal operation” which allows precise clarification of the applicable operating conditions and lists their impact on the technical design of the components. This paper is being made available by the VDMA free of charge to all its members.

It only remains to state that enormous differences exist in the design variants for lift doors. When considering these components, which account for 90 per cent of all lift faults occurring, precise clarification of the intended normal specified operation prior to making a product selection is of particular importance. If we consider that relative to the overall costs of a lift, the outlay for the door accounts on average for only 10 per cent, it becomes clearly evident that using lowcost products frequently does not make for the most economical solution.