Issue 1/2010


01/02/10

Elevator doors for use at public facilities

Dipl.-Ing. Thomas Lernet

At the interlift 2009 the VFA Forum once again scheduled a number of highly interesting speeches by and for elevator industry professionals. Included among them was a very descriptive lecture by Thomas Lernet, technical manager at Meiller Aufzugtüren GmbH in Munich. He addressed the highly topical subject of vandalism in elevators, as well. The talk included descriptions of effective preventivemeasures that are in harmonywith the wide variety of safety requirements in force in Europe.
Category: Issue 1/2010
Posted by: Editor

It seems that the almost daily we see media reports on violent assaults by criminals – many still young in years – in public areas and public transit facilities. A recent homicide at a light rail station in Munich sparked nationwide furor. There an involved citizen showed exemplary civil courage when protecting four children who were being bullied by two older teens. He paid for his commitment with his life. Such reports are often accompanied by a mantra-like call for better surveillance of public spaces and tougher punishment for perpetrators.

Not nearly as spectacular as personal assault but far more numerous are the many malicious acts by delinquents in the public sphere. Elevators accessible to the public are particularly susceptible to vandalism. All across Europe – every day and at many lifts – service is interrupted by such incidents. Thus the German Railways, for instance, feel it necessary to issue daily reports on disturbances of this kind. In addition to the immense time and cost associated with repairing the lifts, it is the systems’ users who suffer. This is especially true for handicapped persons, including wheelchair users, who cannot reach the platforms without a lift.
The speech by Thomas Lernet is summarized below:
Vandalism at lifts
Following a brief, illustrated introduction to the subject of vandalism in general and the reasons behind this phenomenon, the speaker listed the types of elevator damage caused by delinquents:
The consequences may be not just damage to property but also danger for subsequent lift passengers.
Some types of vandalism frequently encountered are:
  • Soiling inside the car (trash, dog droppings, urine …)
  • Graffiti in the car or at the approachareas
  • Scratching and damaging surfaces inthe car and on the doors
  • Damage and theft of light fixtures and lamps
  • Damaging and removing signs and pictograms
  • Damaging controls and indicator elements by applying force or heat
  • Theft of handrails, ashtrays etc.
  • Misuse of the emergency call system
  • Jamming the doors by interrupting the photoelectric beam (chewing gum) or by blocking the doors mechanically
  • Squirting glue into lock cylinders
Preventive measures
Thomas Lernet then discussed appropriate preventive measures:
Carefully selected elevator equipment and specifications for certain elevator components can deter vandalism.
These would include, for example:
  • Optical transparency of the design, making it possible to see into the car from the outside
  • Laminated safety glass, framed at all the edges
  • Components inside the car and at the approach areas made of high-quality, stainless steel, with smooth or textured surfaces (e.g. linen, checkered, leather patterns)
  • Light fixture designs that keep the lamps from being removed from inside the car
  • Installing a shatterproof mirror so that the potential vandal is occupied with himself
  • Video monitoring using a hidden camera , with explicit warning notices
  • Command buttons made of heat- and impact-resistant materials, flush with the surrounding surface area
  • Short waiting and travel times
  • Door systems with strength values significantly higher than those specified in EN 81, Parts 1 and 2
Strength requirements
Thomas Lernet then explained in detail the various standards associated with component strength:
Strength requirements as per EBA (Federal Railway Supervisory Office)
The glass components which are installed, which bear load and/ or which terminate spaces require approval in each individual instance. Such approval is issued by the superior construction supervisory authority or another building offi ce. Application for approval shall include not only the usual documents but also records of testing to demonstrate the stability of fall-prevention glazing following percussive loading with pendulum impact testing.
The stability of the glazing under percussive loading shall be demonstrated by pendulum impact testing procedures for elevator door panels. A “soft” impact body is used here, following the precepts in the former DIN 52 337 (now DIN EN 12 600) and the ETB Guideline governing “Components that protect against falls”.
Requirements as per DIN EN 81-71 

Elevator categories
Before introducing the findings arrived at by Meiller Research in regard to vandalism-resistant elevator door systems, Thomas Lernet described the three elevator categories as per the requirements set forth in EN 81-1/2.
Category 0 elevator
An elevator engineered in such a way that it satisfi es the fundamental requirements of EN 81-1/2.
Category 1 elevator
An elevator engineered in such a way that it satisfies both the requirements of EN 81-1/2 and additional requirements in order to protect the elevator against moderate attempts at willful destruction (see Annex A).
Category 2 elevator
An elevator engineered in such a way that it satisfi es both the requirements of EN 81-1/2 and additional requirements in order to protect the elevator against aggressive attempts at willful destruction (see Annex A).
Engineering measures
It is a well-known fact that Meiller attaches great importance to developing and manufacturing “elevator doors with increased protection against falls”. Thus, for instance, vandalismresistant landing doors developed in cooperation with experts from the Federal Railway Supervisory Office (EBA) met and even exceeded EBA requirements. Many engineering details add up to achieve enhanced stability in Meiller products, proven in realworld practice. Standing behind this is the ongoing research and development work carried out by Meiller. Whenever pendulum impact testing reveals weak points, the engineering details are refined so that the stability of the door systems not only comply with but also exceed the requirements described below.
Thomas Lernet listed the following specifications for materials and door systems, referencing them to the elevator categories previously described. This was illustrated with examples of engineering details adopted for Meiller doors in order to optimize protection against falls:
  • Requirements for materials used in door panels and door frames, e.g. Class A1 as per EN 13 501-1
  • Pendulum impact tests for Category 1 (700 mm) and Category 2 (1000 mm)
  • Retainer systems to keep the door panel in place following impact from a distance of 1400 mm, without the termination of the space being compromised (all categories!)
  • Category 2 with no viewing opening
  • Specific geometry for the closing edge (Category 2)
  • A rod 10 mm in diameter cannot be shoved into the hoistway from the access side
Additional requirements for Category 2:
  • The emergency unlatching opening shall be covered; manual activation and deactivation may be effected only from the machine room or switchgear cabinet or at a control panel used for emergencies and inspections or testing.
  • Car door latching in general
  • No manipulation of the mechanical connections of the door panels, the actuator arm, the door drive motor and the latches inside a period of 60 seconds using the objects described in Annex E
  • Following manual deactivation, the safety system shall be automatically reactivated after a period of from 30 to 60 minutes, with the exception of an inspection trip or activation of the emergency braking switch.
Summary
Before Thomas Lernet concluded his speech he showed film clips of testing conducted in Korea to verify the degree of protection against falls afforded by sliding doors at landings. One dramatic scene was particularly impressive. A tester playing the part of a wheelchair user rolled into an elevator door without braking. The door panel jumped out of the lower guide and the test person plunged into the open elevator hoistway .
In closing, Thomas Lernet emphasized:
  • The requirements set forth in specifications used in tendering for bids need to be carefully examined since they can cause higher costs for the product and for the installation work.
  • There is no 100-percent protection against vandalism.
  • Suitable engineering measures can, however, significantly enhance protection against vandalism.
Examples from practice, shown at the Meiller trade fair booth
This talk by Thomas Lernet was followed closely by many interested listeners. The points made there were underscored by corresponding product samples, on display at the Meiller trade fair booth. Included among them were single-panel landing and car doors in a version featuring high resistance to vandalism, exceeding the requirements set forth in EN 81-71, Class 2. Doors of this design are manufactured specially for the market in Great Britain in order to counteract the extensive vandalism problem prevailing there. Affected are not just public transit operations but also lifts at housing projects in socially deprived areas. Numerous interested visitors stopped at the Meiller booth, too.

 

1/2010

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