Category: Articles

What is an elevator car door locking device?

An elevator car door locking or door restrictor is a device, attached outside of an elevator’s car door

that prevents the door to be opened from inside when the car is in transit between safe landing zones.

What is a safe landing zone?

Also referred to as the unlocking zone, the minimum safe landing zone is a vertical span of 6 inches that extends 3 inches above and 3 inches below an elevator landing. It is permissible for this span to extend up to 18 inches above or below the landing. In the layman’s term the safe landing zone is where trapped passengers can be rescued without having them to climb or jump.

Why are elevator door locking device necessary?

The usage of door locking device as a safety measure had been made mandatory for all elevators in Malaysia by Jabatan Keselamatan dan Kesihatan Pekerjaan (Department of Safety & Health) on 17th March 2011. Likewise in United State of America in their primary rule ASME A17.1, 111.5, also specified the requirement for door restrictors as below:

(a) When a car is outside the unlocking zone, the hoist way doors or car doors shall be so arranged that they cannot be opened more than 4 in. (102 mm) from inside the car.

(b) When the car doors are so arranged that they cannot be opened when the car is outside the unlocking zone, the car doors shall be open from outside the car without the use of a special tool.

(c) The doors shall be unlocked when the car within 3 in. (76 mm) above or below the landing and shall be permitted to be unlocked up to 18 in. (457 mm) above or below the landing.

For elevators installed under the 1980 edition of ASME A17.1 and later, door restrictor guidelines are provided in ASME A17.1 1998b Rule 111.5/111.12 or ASME A17.1 2000 Item 2.12.5.

The A17.1 Handbook Safety Code for Elevators and Escalators, 2000 Edition, Section 2.12.5, explains the reasoning behind the use of door restrictors in this way:

When a passenger elevator is outside the unlocking zone it is unsafe for a passenger to try to exit through the elevator entrance unassisted. In fact, there have been many reports of fatalities due to this condition. A person inside the car should not be able to accomplish their own emergency evacuation through a hoist way door when the car is located outside of the unlocking zone. This requirement may be met by restricting the opening of the car door or the hoist way door.

Industry and safety experts have agreed that during emergencies or power-loss events, the safest ways to rescue elevator passengers are inside the car until they can be rescued by professional responders.

Type of Elevator Car Door Locking Device

The first type, mechanical door restrictors are problematic because they tend to be noisy and need frequent adjustment and realignment.

The second type, electromagnetic door restrictors use photo or magnetic sensors instead of metal-to-metal contact. However, installation and calibration of the switches and levelling plates used by these devices are time-consuming but once adjusted it will last for years.

Our Product

Our product is of electromagnetic type and was designed to function during power failure as it was built in with backup power supply. The system can be turned off by using toggle switch when rescuing trapped passenger at the car top. The designed is versatile and can be installed to various elevator brands; it worked independently without interrupting the original control sequence and function.

How it works?

Our product comes with three (3) major components:

a) Power and backup supply units – Provide power supply for locking device even power failure.

b) Photo sensor – To detect safe landing zone to disengage the locking device

c) Locking device – To lock the door by using electromagnetic power when out of safe landing zone.

The photo sensor will sense the car position whether the car is at the safety landing zone; if yes, the lock will be disengaged while if not the lock remains activated.

(1) The owner of every lift shall ensure that such lift is maintained. 

(2) For the purpose of complying with paragraph (1) of this regulation such owner shall enter into an agreement with an approved firm for the periodic examination and maintenance of such lift. For the purposes of this regulation, an approved firm means a firm which has satisfied the Chief Inspector that it employs persons suitably qualified and trained (hereinafter referred to as the competent person) and controls equipment and facilities to ensure a proper standard of lift examination, service and maintenance: 

Provided that such agreement shall not relieve the owner from the responsibility of maintaining the lift well enclosure where such enclosure forms an integral part of the building in which the lift is installed.

(3) It shall be the duty of an owner to inform an Inspector of :

• the date of commencement of such agreement; and 
• the name and postal address of the approved firm; and 
• the date of expiry of such agreement. 

(4) Such agreement shall be for a period of not less than one year, and shall state the name of the competent person employed by the approved firm who is to make such periodic examination and be responsible for such maintenance.

(5) Such person shall thoroughly examine the lift at least once in every three months and cause the lift to be serviced and adjusted once in every month.

(6) A register in respect of every lift in the form shown in the Second Schedule to these regulations shall be kept on the premises in which the lift is installed wherein shall be recorded –

• details of every examination, servicing and adjustment referred to in paragraph (5) of this regulation;
• details of any repair to the lift considered necessary by the competent person and subsequently the date when such repair has been effected;
• details of the breakage of any suspension rope, the failure of any part of the lift machine, over-speeding of the car whether or not safety gear functioned and any other occurrence resulting in the lift being immobilised; and
• such other information as the Chief Inspector may from time to time direct.

(7) Such entries as are referred to in paragraph (6) of this regulation shall be made by the competent person within one week after the event to which it relates.

(8) Such register as is referred to in paragraph (6) of this regulation shall be produced for the Inspector’s examination at every regular inspection of the lift and as and when requested by the Inspector.

(9) On receipt of advice from the approved firm that repairs to the lift are necessary the owner shall forthwith arrange to have such repairs effected, or if in doubt as to the necessity therefor refer the matter to an Inspector. For the purpose of this regulation, any recommended repair recorded in the register in accordance with sub-paragraph (b) of paragraph (6) of this regulation shall be deemed to constitute receipt of advice.

(10) If after receipt of such advice as aforesaid the owner neither causes the repairs to be effected nor refers the matter to the Inspector within a period of one week the approved firm shall forthwith inform the Inspector of the facts of the case.

(11) It shall be the duty of the owner of every lift to ensure that, in respect of such lift –

• the lift well and pit is maintained in a dry and clear condition, and no rubbish allowed to accumulate therein, nor any part used for storage;
• no material not forming part of the lift equipment is placed on the top of the lift car;
• the lift is not operated at a load greater than the contract load as specified in the certificate of registration and the car plate fitted in accordance with paragraph (4) of regulation 7;
• in the case of any lift other than an automatic control lift, it is not operated unless in the charge of a car attendant who shall be not less than eighteen years of age; and
• no wire or current carrying device is substituted for the proper fuse or circuit-breaker in any lift control circuit.

List of References:

Department of Occupational Safety and Health 2023, Regulations Under Factories and Machinery Act 1967 (Act 139), accessed 13 February 2023, https://www.dosh.gov.my/index.php/legislation/eregulations/regulations-under-factories-and-machinery-act-1967-act-139

Factories and Machinery (Electric Passenger and Goods Lift) Regulations, 1970

(EMERGENCY BATTERY OPERATED POWER SUPPLY)

What is EBOPS?

Emergency Battery Operated Power Supply (EBOPS) is designed as an accessory for elevator system. It provides backup power supply for alarm bell, lighting & ventilation whenever there is a case failure of normal power supply.

Upon power failure, EBOPS will generate a sinusoidal wave AC power supply from DC backup batteries to keep the lighting and ventilation fans for elevator car on working condition. When the main supply resumed, the batteries will be recharged immediately from the changeover back to normal supply.

The purpose of the installation of EBOPS was to keep the passenger inside the lift comfortable and safe just in case of mantrap.

EBOPS was an enclosed steel cabinet consists of ampere meter, voltage meter, printed circuit board, LED indicators, rectifier and inverter with a separate battery compartment. The unit will be installed at the lift machine room.

Our EBOPS Features

• Fulfilled and complied to European Union Directives & Singapore Standard SS209.
• A complete range of EBOPS series applicable to different type of requirements.
• Advanced Power-Electronic technology with modular and simple design concept for most efficient maintenance and services.
• Most compact, unique and reliable product with quality.
• Revolutionary performance for all passenger and cargo elevators.

JKKP Enforcement

Jabatan Keselamatan & Kesihatan Pekerjaan (Department of Safety & Health) Malaysia had enforced the installation of EBOPS on 10th June 2011 for all existing elevators as well as new installation.

With this enforcement, the department hoped that:

1. The trapped passenger will not force opened the door that could lead to accident.
2. The alarm bell which meant to alert for external rescue is functioning always.
3. Lighting and ventilation are working during power failure to ensure visibility and least suffocative   environment.
4. Improve the safety of women and children who are using elevators.

Maintenance

EBOPS unit needs to be serviced and maintained every six (6) months to ensure its functionality.

The scopes of maintenance are as below:

a) Check the battery current and voltage.

b) Check the rectifier and inverter units.

c) Check the battery terminal, mounting and wiring for looseness and condition.

d) Check battery water level if required top up.

e) Tripping of main supply for activation of EBOPS.

f) Test the change back to charging mode upon restoration of power supply.

g) Check the condition of ammeter, voltmeter and other display LEDs are in order.

h) Housekeeping