As the laser industry continues to grow rapidly, a lack of understanding of laser safety standards has led dangerous misconceptions-such blindly pursuing to as "CE certified" marked products or simply choosing the "lowest price". These practices pose serious safety risks to end-users and the entire industry. 

DIN EN 12254:2012-04 EN 12254:2010-AC 2011 (E) : This European Standard specifies functional requirements and a product labelling applicable to temporary and permanent passive guards (in the following called screens) for protection against laser radiation. This standard includes test methods for testing functional performance and the specification of the user documentation to be supplied with the product. 

The screens are designed to protect the user from 

• unintentional exposure to direct and/or diffuse laser radiation 
• a time-Iimited exposure to laser radiation, based on the functional requirements determined by risk assessment

This European Standard applies to supervised screens for installations in working places at which laser radiation up to a maximum mean power of 10 or single pulse energy of 30 J occurs within the spectral range between 180 nm (0.18 µm) and 10 ⁶nm (1.000 µm).
Does your washing machine at home has 
This European Standard (EN12254) applies to the protection against laser radiation only. This standard does not apply to other hazards including hazards from secondary radiation that can arise during, for example, material processing

This European Standard gives guidance on how to select such screens.

Laser enclosures and housings that are supplied as part of the laser product or are supplied to be fitted to a Laser system to form a laser product (according to EN 60825-1) are not considered to be within the scope of the standard.  

Taking a manufacturer's EN12254 test report as an example: This test report states that, according to the EN12254 standard, in the 1050-1400 nm wavelength range, the protection level is D AB5.

Referring to the standard table, the irradiance is 2.5 × 100 W/m2.  When converted, this equals 2.5 W/mm2.  During actual testing, however, the power applied to the surface of the protective curtain was only about 2 W (the test report indicates the actual applied power was 2.35 W).  It is not difficult to see that the safety capability of this curtain is only equivalent to that of a basic product and is seriously misaligned with the demands of industrial applications.

Misleading Units in Test Conclusions: EN12254 specifies a test spot size of 1 mm in diameter, but test results are often expressed in J/m2 or W/m2, which leads to two major issues
Issue 1: The correct result should be in J/mm2 or W/mm2.  

A material that withstands energy on a 1 mm2 spot doesn’t imply it can handle 100,000x the energy on a 1 m2 area.  

Converting 2.5 W/mm2 into 2.5×10⁶ W/m2 is misleading.  

For example, a protective rating of D AB5 in the 1050-1400 nm wavelength range, the irradiance is 2.5×10° W/m2.  However, the actual test result should be expressed as 2.5 W/mm2.  The actual irradiated power is only around 2 watts.  Simply converting this into 2.5×10⁶ W/m2 can be misleading, making people think that the product can withstand 2.500.000, watts of laser power!  Just imagine what it would mean to have 2.5 × 10⁶ watts of laser energy applied to 1 square meter!

Issue 2: Laser damage depends not only on energy density (per area) but also on total energy exposure.  Even if a high energy density is applied to a 1mm spot, the total energy might be low and not cause damage.  Conversely, a lower energy density over a large area or long exposure can cause significant harm.  Laser protection should be evaluated based on EN 60825-4, using the expected FEL (Feasible Emission Limit) and ensuring the PEL (Protective Exposure Limit) of the protection product exceeds it.  Each use case requires a specific safety assessment.