ISO 11553 is the international standard for laser processing machines. It is implemented as European normalised standard EN12626. During 2005, this standard will be reissued as ISO 11553-1, the ‘-1’ reflecting the fact that development work for a ‘-2’ standard for hand held laser processing devices is underway.

The main reason for the reissue, though, is to put right a major limitation that unnecessarily prevents many models of laser processing machines from complying. When the standard was first published in 1996 its scope was limited to machines that strictly conformed to the requirements of a Class 1 laser product (in accordance with IEC 60825-1). This effectively required that the laser radiation had to be totally enclosed and human access totally prevented; thus eliminating a large number of CO2 laser processing machines - for example open topped flat bed laser cutters.

Though not totally enclosed, these machines are generally safe when used as intended and can be assessed to be in compliance with the Machinery Directive and thus CE marked.

The applicability of ISO 11553-1 (2005) to a much wider range of laser processing machines, is extremely valuable, since it provides requirements that address a wider range of hazards usually associated with a processing machine. The requirements for guarding are now set by risk assessment rather than by the rigid requirements of Class 1. Application of the risk assessment requires the environment in which the machine is situated to be specified together with degree of control that is exercised over access and use of the machine.

With regard to the location of the laser processing machine three situations have been defined and the degree of protection to be provided is specified for each.

The first situation is a location with “controlled access” i.e. a location where the hazard is inaccessible except to authorised persons who have received adequate training in laser safety and servicing the systems involved. The second situation is a location with “restricted access” where the hazard is inaccessible to the public, but may be accessible to other observers or other untrained personnel who are kept from being exposed to the hazards of laser processing by barriers or other methods. Where the laser processing machine is to be used in either of the above two locations, the laser guarding may be determined by risk assessment methods, taking into account the personnel who may have access to the machine: in “controlled” locations the personnel who have access are assumed to be both authorised and trained in laser safety, whereas in “restricted” locations the public are not allowed but those with access are authorised but they might not be trained in laser safety and thus require to be provided with protection.

The fundamental requirement of the revised laser machine standard is that, during production, it shall not be possible for persons to be exposed to levels of laser radiation exceeding the maximum permissible exposure (MPE) over a period of 3 104 seconds (8 hours). To satisfy this requirement, the standard requires that the following conditions be met.

o ARisk Assessment shall be performed.
o Unauthorised human access to a danger zone should be prevented by engineering measures as specified in IEC 60825-1, ISO 12100-1 and ISO 12100-2.
o If access cannot be prevented, exposure above the ocular MPE shall be eliminated by use of engineering or administrative controls, including Personal Protective Equipment (PPE).

Locations that are both unlimited (i.e. uncontrolled) and unrestricted are those where the public may have access. In these cases the laser processing machine must meet the requirements of a Class 1 laser product.

Other requirements within the standard, which require consideration of all the other hazards associated with machine tools, fume extraction, the by-products of laser processing etc., remain unchanged.

Changes to other standards
In relation to the safety of machinery in general, the revised ISO 12100-1 and ISO 12100-2 standards for the Safety of Machinery supersede EN292, which was withdrawn in December 2003, thus allowing other ISO standards and EN standards to be synchronised. The effect on the laser processing machine standard is that the latest version of ISO 11553-1 will be adopted by CEN as EN ISO 11553-1 and the CEN standard EN12626 will be withdrawn. This synchronisation will significantly benefit the rest of the
world as now only one machine standard will be applicable in Europe and outside Europe. However, this achievement has not been without its trials; the timing of the release of the ISO 12100 series delayed publication of the laser processing machine standard and there was considerable conflict with the EU Commissioners' Consultants, which took significant time and effort to resolve and delayed publication of the revised ISO 11553-1 standard by over two years.

The Noise Directive
The end of 2003 saw the introduction of a revised Directive relating to noise in the workplace. This Directive places constraints on manufacturers of equipment and on employers using any equipment in the workplace. Thus the laser processing machine standard will have to undergo one more revision to include the requirements placed on manufacturers to meet the revised Noise Directive. Work is currently progressing to establish a set of requirements that meet the needs of the Directive but do not become too onerous on equipment manufacturers. During discussions with the EU Commissioners' Noise Consultant, there was definite danger that the standard would be dominated by the noise requirements (specification, verification and documentation requirements). Fortunately, other machine tool standards groups have been wrestling with this problem for the last 15 years and their experience will benefit the laser processing machine standard. The next revision standard will probably not appear until the end of 2006 to coincide with end of the transition period for application of the Noise Directive.