Laser Warning Signs and Warning Systems
Clear warning signs are an important part of laser safety. Laser warning signs indicate the presence of laser radiation, identify laser-controlled areas and help personnel understand when access requires particular precautions. In industrial laser installations, permanent signs can be complemented by illuminated warning signs that indicate the current status of the laser system.
Warning signs form part of the overall safety solution and are used together with measures such as protective enclosures, interlock systems and other technical and organisational safeguards. IEC 60825-1 covers the classification and safety requirements of laser products, including requirements intended to provide users with appropriate information about hazards associated with accessible laser radiation.
Why are warning signs needed around laser installations?
Laser radiation can be invisible, which means that a person cannot necessarily determine simply by looking at the equipment whether a laser hazard is present.
Warning signs help make these hazards clear and can be used to:
- warn of the presence of laser radiation
- identify laser-controlled and restricted areas
- provide information about the laser hazard
- indicate when specific protective measures are required
- show whether a laser installation is active or in a safe state.
The signage should be selected and positioned according to the installation and its risk assessment.
Passive laser warning signs
A passive laser warning sign provides permanent information about a laser-related hazard. This may include the familiar yellow warning triangle with the laser radiation symbol as well as supplementary information about the laser and associated hazards.
Typical locations include:
- entrances to laser-controlled areas
- laser enclosures and safety cells
- laser equipment
- access and service panels
- areas where specific laser safety procedures apply.
The marking and information requirements for laser products are addressed in IEC 60825-1.
Illuminated and active warning signs
In an industrial installation, it is often important to know not only that a laser is present, but also the current operating status of the system.
Illuminated warning signs can use LEDs, different colours and messages to provide a clear visual indication of the laser installation’s status.
For example, a two-state sign can indicate:
NO HAZARD / LASER OFF when the installation is in a safe state.
DANGER / LASER ON when the laser system is armed or operating and specific safety restrictions apply. Lasermet, for example, uses two-state LED warning signs that automatically switch between these indications according to the state of the associated interlock system.informationen automatiskt följer systemets säkerhetsstatus. Det är exempelvis så Lasermets tvåläges LED-skyltar fungerar tillsammans med deras interlocksystem.
Warning signs and interlock systems
One of the main advantages of an active warning sign is that it can become an integrated part of the laser safety system.
When connected to an interlock controller, the indication can change according to conditions such as:
- whether the laser system is armed
- whether the laser is operational
- whether doors or other access points are closed
- whether the safety circuit is ready
- whether a fault or emergency stop has occurred.
This gives personnel outside the controlled area immediate visual information about the status of the installation. Systems such as Lasermet’s ICS-9 can control warning signs together with door interlocks, magnetic locks, beam shutters and emergency-stop circuits.
Positioning laser warning signs
A warning sign must be positioned where the information is needed before a person enters or accesses the hazardous area.
This commonly means installing signs at entrances to laser-controlled areas and on or adjacent to equipment where a laser hazard exists.
For a laser safety cell, for example, an illuminated warning sign can be mounted above or beside the entrance so that the system status is clearly visible before anyone enters. For laser guards, IEC 60825-4 specifically addresses issues including human access, interlocking and labelling, as well as the design of protective housings and enclosures for high-power lasers.tvåläges LED-skyltar samtidigt som dörrinterlock, nödstopp och laserutgång övervakas.
Warning signs do not replace protective measures
A warning sign communicates a hazard – it does not remove the hazard itself.
Depending on the laser installation and risk assessment, additional safety measures may therefore include:
- laser safety enclosures or cells
- laser safety curtains
- interlock systems
- safety switches
- laser safety windows
- personal protective equipment
- procedures and training.
The appropriate combination of measures depends on the laser, process, installation and potential exposure conditions.
Standards and laser safety information
IEC 60825-1 is the central international product safety standard for laser products and covers laser classification and safety requirements.
For laser guards and protective enclosures, IEC 60825-4 is particularly relevant. It addresses permanent and temporary laser guards and specifically includes matters such as human access, interlocking and labelling. It also applies to components including panels, viewing windows, laser curtains and walls.
The required warning signs and safety measures should always be determined from the specific installation and its risk assessment.
Warning signs and warning systems from LMI AB
LMI AB offers solutions for clear warning and status indication around industrial laser installations.
Depending on the application, warning signs can be used independently or integrated with interlock systems, laser safety cells, protective enclosures and other safety functions to create a coordinated laser safety solution.
Need help with warning signs for your laser installation?
The appropriate solution depends on the laser, process, installation layout and how personnel access the area. Contact LMI AB and we will help you identify a suitable solution for warning and status indication around your laser installation.
Urban Gärds
Contact person for warning signs and warning systems