Safe Key sequencing access systems serve as safety devices on equipment and hazardous areas.

Access Control Systems with Safe Key Sequencing Security

Breech of safety within ships is a very real concept. Unfortunately it happens, if not regularly, then a lot more frequently than it should.

Systems with a safe sequence of keys serve as security access control systems or action control systems in many mechanical, hydraulic, pneumatic, electromechanical, and electrical applications.

A safe key sequencing (interlock) system can be defined as a device that prevents you from having an inappropriate access, or adjusts the system to a safe state if you have an inappropriate or unauthorized access.

In the context of safety, safe key sequencing systems can prevent a user/operator from making unsafe actions, or minimize the hazard of unsafe actions by rendering the machine in a safe condition when an unsafe action occurs. For example, a guard may be sequence locked to prevent a machine operation when a guard is removed, or a control may be key sequence locked to make it non-operational if a dangerous condition will result. Safety sequencing locks may have additional or combined features to reduce hazards. Access is not limited to input / output and critical operation e.g. open / close valve. This system can operate with simple mechanical systems (locks only), or complex electro-mechanical, hydraulic or pneumatic systems.


Thanks to its simplicity and effectiveness the principle of transfer, the interconnected system with a sequence of key access, security can guarantee that the worker will follow the safe step by step procedure before an access to a dangerous area or machines.


The Key Transfer

“More than a principle ... The way forward to optimum safety”

Based on the idea that a key can not be in two places at the same time, our locking systems force operators to perform a predetermined sequence routine, particularly in relation to maintenance and operating requirements. In its most basic form, the key transfer principle involves the positive locking of the power source and access point of a machine, with locks operated by a single common key. Our extensive range of locks permits the locking of most control circuits, switchgear and access points.

This technology,  is considered to be the most effective form of industrial safety.

Typical application solutions include :

  • Electrical Systems
  • Compressor Stations
  • Loading or unloading operations
  • Cranes
  • Conveyors
  • Valves and liquids safety
  • Ship/shore loading sequencing
  • Fire Protection
  • Gas areas
  • Enclosed & confined areas
  • Maintenance
  • and many others

- Substantial reduction of accidents.
- Easy to install and to integrate on your working routine.
- Predetermined sequence of actions to follow in order to gain access to a dangerous area or machine.

- Mechanical configurations can be used in ATEX zones 1,2


Main Circuit Breakers

Mechanical interlocks are fitted to main circuit breakers to prevent racking-out if still in the ON position. Care must be taken not to exert undue force the breaker will not move, otherwise damage may be caused to the interlocks and other mechanical parts.

Electrical interlock switches are connected into circuit-breaker control circuits to prevent incorrect sequence operation.

When a shore-supply breaker is closed onto a switchboard.

The ship’s generator breakers are usually interlocked OFF to prevent parallel running of a ship’s generator and the shore supply.

CO2 Control

The CO² extinguishing system needs to be isolated and put in a safe state (towards atmosphere) before entry to the area.


Starting and testing emergency generator

An interlock is required so that the emergency generator and Main power of the ship cannot be supplied together.

Interlocking Switchgear

Interlocking switchgear ensures that personnel remain safe and equipment is operated to the correct procedures.  Using  a  well-designed  interlocking  scheme  will  ensure  that  personnel

cannot  access potentially dangerous areas without the switchgear system being put in a safe state.  A good interlocking scheme will also ensure that the system operates correctly and there is no chance of, for example, switching two incoming feeds on to a common bus bar. This ensures that the equipment is not damaged and the risk of fire and arc flash are greatly reduced.

Processes where interlocking in switchgear are particularly relevant are:

  • Personnel access
  • Earthing  systems
  • High, medium and low voltage hazards
  • Switching incomers on to common supply busbars
  • Switching UPS systems and generators on to common supply busbars
  • Controlling the supply from multiple incomers

Running direction interlock

Interlocks are the blocking devices which ensure that the engine is started or reversed only when some conditions are fulfilled or satisfied. Running direction interlock is an essential trait that prevents the injection of fuel to the engine when the telegraph doesn’t synchronise with the running direction of the engine. It is an important application in the crash manoeuvring when the starting air is used to apply brakes on the engine by reversing the operation.

Turning gear interlock

Turning gear interlock is another important thing that prevents the admission of starting air to the engine cylinders when the turning gear is engaged. If the starting air is admitted with the turning gear engaged, then the turning gear along with the motor will fly off puncturing the bulkhead. Thus the interlock is necessary to prevent such accidents.

Valve interlocks

Valve interlocks prevent human errors and guide valve operator through predefined valve operating sequences. Unique keys are used to only allow the right valves to be opened or closed in the correct order.

Ship to shore power

Interlocks can be used in many process or procedural systems within Ports involving the transmission of electricity, including crane movement, ship to shore power, and local substations or backup generators.

Key Management

With Smart key Management

A key management combination with real-time traceability. Using RFID technology to guarantee a high level of reliability, the Smart Key Manager can accept up to 16 key modules, controlling a total of 256 keys.

The system indicates which keys are present in or absent from the cabinet, who has taken each key and when. Via email, managers can choose to be kept informed of key movement, inform others and monitor several levels of administrators.

Full or partial access to keys can be given remotely via the interface, ensuring that individuals can only access keys relevant to them. The Smart Key Manager offers three levels of security by requiring users to prove their identity with a badge, PIN code or a combination of the two.