Cleanrooms can be distinguished based on the number and size of particles in the air. The international ISO 14644-1 standard divides them into several categories, but in the case of light fixtures there are simpler requirements that can be formulated. Make the surface easy to clean: any dirt can be easily removed from the lamp body and the cover! Dust must not settle on any surface! This is an extremely important aspect, since hygiene in operating theaters or any other hospital area is primary and more than problematic if dust stops on the light fixture! High IP protection: Basically, this criterion and the previous ones are also related, because a luminaire with high protection against dust is usually also equipped with high protection against moisture. In these rooms, the required minimum degree of protection is IP54.