Laser Testing to BS EN 60825-1
The most recent version of the standard was released in 2014. This revised how pulse lasers were handled, as well as introducing the new Class 1C; additionally, the Condition 2 measurement of 70 mm was removed, and the Naked Eye condition (condition 3) at 100 mm is now the closest distance for measurement.
Furthermore, IEC 60825-1:2014 allows for the testing of lasers under IEC 62471 if they are used in the same circumstances as conventional lamps.
Laser Testing Packages
The full Laser Testing package includes the following services:
PROTOTYPE & FINISHED PRODUCT TESTING
We will test and certify your prototype or completed product to the appropriate standard or standards and provide a full test report including details of:
- Measurement test results
- Required Engineering Controls
- Accessible Emission Limits
- Required information in User Manual and Product Brochures
- Required Labelling
- Failure modes of drive electronics and other reasonably foreseeable failures affecting safety
We will issue a classification conditional on making the listed changes (such as labeling, user information, and minor engineering changes) if a product fails to meet the desired classification due to minor failures. When a retest is required, it is usually done at a reduced cost.
CONSULTANCY AT THE DESIGN STAGE
Imagine this scenario:
You work on a laser product for two years. Understandably, your priority is to produce a high-performance product at a reasonable price. Laser safety testing is far down the priority list. So you submit your product for laser safety testing only when it is close to production, only to discover that changes are required to meet the desired laser classification. Even minor changes can be costly and cause production and sales to be delayed. Significant design changes can be time and money consuming.
To avoid this scenario, we recommend that you involve us in the design process early on to advise you on the desirable class of your product and ensure that it is designed to meet the requirements of that class.
CE MARKING, SAFETY STANDARDS, FDA (CDRH) REPORTS
As part of the CE marking process, all laser and LED products sold in Europe must be certified to EN 60825-1. The same requirements apply to LED products as they do to laser products.
Additional standards may apply such as:
- EN 60825-2 for fibre optic laser communication products
- EN 60825-12 for open beam laser communication products
- Low Voltage Directive
- Transmission Equipment
- Machinery Directive
- General Product Safety
- Medical Devices Directive
- Radio & Telecommunication Directive
Manufacturers can self-certify their equipment to EN 60825-1, but the standard is highly complex and difficult to interpret, and in many cases, an expert is required to obtain the correct laser Class for the product. In any case, many manufacturers prefer to have independent verification of their classification requirements compliance.
Product conformity is achieved in Europe by requiring manufacturers to certify to the relevant standards for their product. The manufacturer is responsible for identifying relevant standards, designing the product accordingly, and making a declaration of conformity in the user instructions. The various national enforcement bodies are then responsible for detecting non-compliances and intervening where necessary. The standards are set by expert committees and are constantly reviewed and improved. This system places a great deal of responsibility and trust in the manufacturers, but it also allows standards to be kept up to date with changing technology, knowledge, and current practice.
For laser products, the situation in the United States is somewhat different. Product safety in the United States is governed by federal regulations enforced by the Food and Drug Administration (FDA), and in the case of laser products by the FDA’s Center for Devices and Radiological Health (CDRH). The Federal Regulations are written into law, and manufacturers are required by law to follow them. They must also register the products with the FDA before selling or importing them into the country.
The regulation that governs laser products is known as 21 CFR 1040.10. This regulation was enacted into law in the 1970s and has remained unchanged ever since. As a result, it is now very out of date. Nonetheless, it remains in effect, and until recently, all laser products sold in the United States had to comply with this regulation.
The CDRH issued ‘Laser Notice 50’ in 2001, indicating that the FDA will now accept IEC classification and labeling. Manufacturers selling their products in the United States can now choose between IEC 60825-1 classification and labeling or 21 CFR 1040.10. In both cases, the products must be FDA-registered. LED products are not subject to 21 CFR 1040.10 (or any other Federal Regulation) and do not require registration.
Despite the fact that the CDRH laser regulations are Federal Law, registration is a’self declare’ process, similar to EU regulations. However, CDRH does occasionally review submissions and, if they do not meet Federal Regulations, may prohibit the use of the offending products or require that all equipment in place be changed to comply. It is also worth noting that the FDA never ‘approves’ equipment, though on rare occasions they may indicate that they have reviewed the submission and have no further questions about it.
IEC 60825-1, IEC 60825-2, and IEC 60825-12 are currently identical to the corresponding EN standards (though EU standards agencies reserve the right to deviate from them for safety reasons). These standards apply to Japan, Australia, Canada, and pretty much every other country that hasn’t already been covered.
Because IEC 60825-1 is also applicable in Europe (under the EN designation) and the United States (with the exception of a few clauses), it has become the global laser safety standard.
SINGLE FAULT FAILURE REQUIREMENTS
EN and IEC 60825-1 and -12 require classification to be performed at the highest emitted power under reasonably foreseeable single fault failure conditions (‘reasonably foreseeable failure conditions’ is used by EN / IEC 60825-2). This is most noticeable in electronic drive circuits for diode lasers, where a component failure, such as a short circuited transistor, may increase the output power of the laser and cause the product to emit above the AEL of the desired Class. In this case, unless the electronics are redesigned to eliminate the problem, the product must be classified at a higher level. Many manufacturers previously overlooked this requirement and succeeded in complying because the diodes were generally low power and would frequently be destroyed very quickly when subjected to a higher drive current than that intended by the circuit design. However, as the power and cost of laser diodes have decreased, most manufacturers are using higher power diodes operating at a small percentage of their maximum output to increase reliability. As a result, if a component fails, increasing the drive current of the laser diode, many of these devices will happily run at twenty times the intended product output. This may present not only a classification problem, but also a serious safety issue in some cases.
If the electronics fail, the optical power output may increase significantly, and the device may far exceed the classification originally assigned under ‘normal’ operating conditions. In some cases, the failure may render the system dangerous when it would be safe in ‘Normal’ operation. In medical applications, especially in eye procedures and other situations where children and the general public have access to the laser output, special care must be taken to ensure single fault control is present and effective. As a result, the IEC/EN standards require that the desired classification Accessible Emission Limit not be exceeded in ‘Normal’ and ‘Single Fault Conditions’.
Suggested methods of designing laser/systems drive circuits to enable compliance with the single fault requirement
- Induced catastrophic failure of the diode in a very short time (approx: 1sec)
- Secondary optical monitoring and independent shutdown
- Optical attenuators
- Current monitoring with independent shutdown
- Modulation watchdogs
- Critical component cross checking (with independent shutdown)
Some of these systems have their own issues, particularly the current monitoring. Lasers have a fairly large temperature-dependent change in lasing threshold, and because the optical output/current drive characteristic is usually steep, fairly precise current control is required. Independent optical monitoring and shutdown is likely one of the most commonly used methods and is regarded as the best arrangement because it effectively covers the case where power creeps up due to contamination of the monitoring diode or partial failure of a component, as well as catastrophic failure.
This is just a sample of the methods that could be used to meet the single fault requirement in IEC/EN60825-1. If necessary, Lasermet will act as consultants, providing advice on specific applications, the applicability of a given design, and specific information about the likely problems with each system.
INFORMATION REQUIRED FOR TESTING LASER PRODUCTS
TO BS EN 60825-1
- Product Classification
- Any embedded lasers’ class (if applicable)
- Wavelengths that are available during normal operation
- Typical powers available during normal operation
- Is the laser capable of firing continuously or repeatedly while pulsing?
- Laser source datasheets
- Interlock datasheets and logic diagram (if applicable)
- One operational unit, as close to the final version as possible
- Brief description of product, its function, and number of laser sources
- Unit set-up / operating instructions
- Circuit diagrams relating to laser power (if below Class 4)
- If these cannot be supplied, then 1 spare laser module
- Details of pulse structure
- Any additional equipment necessary to operate unit
- Copies of all required laser safety labels
- Copy of product user manual
TO BS EN 60601-2-22
- Same requirements as testing for BS EN 60825-1
- Power density, energy density, and closest point of access
If some of the above-mentioned information/items are not supplied, it may take a long time to analyze the circuit, resulting in additional test costs. In some cases, classifying the equipment may be impossible without all of the relevant samples/information listed above.
As a result, we strongly advise manufacturers to carefully consider their drive electronics to ensure that the reasonably foreseeable single fault failure requirement is met. Otherwise, serious issues are likely to arise during the testing stage, when manufacturers are under pressure to get the product on the market.
UKAS Accredited Testing
Lasermet is the UK’s leading test house for testing to the following standards:
- BS/EN 60825-1 / IEC 60825-1
- BS/EN 60825-2 / IEC 60825-2
- BS/EN 60825-12 / IEC 60825-12
- BS/EN 60601-2-22 / IEC 60601-2-22
- 21 CFR 1040.10
- BS/EN 60825-1:2014, 2007, 2001 (off-site)
- BS EN 62471
Lasermet also offers UKAS-accredited laser safety testing at customer sites. This is especially useful for users of large laser systems that are difficult to transport.