Late 2007 saw the publication of EN 60825-1:2007 – Safety of Laser Products Pt1: Equipment classification and requirements. This revised prime standard for laser products accurately reflects the revised IEC 60825-1:2007 and supersedes the earlier version of 60825-1:1994 together with subsequent amendments and corrigenda.
For compliance purposes within the EU either version of the standard (i.e. 2007 or 1994) may be used up to September 2010, at which time the earlier version of the EN standard must be withdrawn. However where the IEC standard is used for compliance purposes (presumably at least for compliance claims on equipment going outside the EU) then IEC60825-1:2007 must be used as IEC withdrew all earlier editions of the standard immediately on publication of the 2007 document.  This latter situation will also mean a revision of other IEC documents where individual requirements and clause numbers references have changed as a result of this new edition.  For example, IEC 60825-4 for laser guards will be reissued with revised references when the next Annex is published later in 2008.

Why the change?
Standard 60825-1:2007 has changed for two major reasons: to remove light emitting diodes (LEDs) from the requirements of the standard, and to remove the User’s Guide, which underwent a major revision some years ago and is issued separately as IEC TR 60825-14:2004 – Safety of Laser Products Pt14: A users' guide. However there are also a number of other changes, some of which are important.

Non-laser sources
The LEDs that have been removed from the scope of the product safety standard are those that are derived from semiconductor devices having large sources sizes and producing optical radiation that may not be coherent. It has been widely felt that these devices were generally not hazardous in practice and that classification requirements were inappropriate. 
In general LEDs are now to be assessed using the standard IEC 62471:2006 (CIE S009:2002) - Photobiological safety of lamps and lamp systems. However, despite this change there remains considerable concern over high power LEDs, especially those producing ultra-violet light on account of the cumulative effects of UV exposure. Semiconductor devices that may generally be known as LEDs but produce spontaneous or stimulated coherent radiation are still covered by the 60825-1 standard.

Users' guide
Despite the removal of Section 3 (User’s Guide) of the older 60825-1 standard, not all user information has been removed from the revised Part 1. Annex A now collects together most of the information relating to Maximum Permissible Exposure (MPE) values.  Annex B still gives examples of calculations. Annex D describes the biophysical considerations with Annex E giving additional information to aid the expression of MPEs and Accessible Emission Limits (AELs) as radiance.

Additional requirements

Measurement for classification
Although the laser classification system remains unchanged in terms of definitions, there has been a significant change in the measurement geometry for classifying lasers emitting highly divergent beams. To address concerns that the measurement of power and energy for assessing the Class of high divergence sources was unduly restrictive (i.e. through a 7 mm aperture located 14 mm from the source to simulate the use of a hand-held magnifier) the measurement condition has been relaxed by moving the location from 14 to 70 mm in the new edition, meaning that some high divergence sources can be given a lower classification. However, there is an additional labelling requirement for some such sources to warn the user of skin hazards close to the source.

Embedded products
There are new restrictions on the level of accessible laser radiation that is permissible with embedded laser products.  In particular, for user maintenance of products that are Class 1 must not permit access to levels of laser radiation of Class 3B or 4.
There is also an additional requirement for "walk-in" enclosures, that where access during operation is intended or reasonably foreseeable, engineering means must be employed to prevent emission of Class 3B or Class 4 laser radiation if someone is inside the enclosure.
Another new requirement is for Class 4 laser systems to be equipped with a manual reset, to enable resumption of operation following use of the remote interlock or interruption of the power source.

Definitions
Some terms have been added to the list of defined terms and others have been  expanded. One newly defined term is “accessible emission”, a term used both in the context of measurements for classification and also for quantifying "human access", one of the terms that has been expanded in the new edition.
The definition of human access is particularly important for designers of fully enclosed embedded laser products (e.g. laser machines) since in this case the product's classification (Class 1) is based on non-accessibility. In this context the revised definition makes the following changes:
a)         (for enclosures of lasers of 3B and below) an assessment is made of the capability of a cylindrical probe with a diameter of 100 mm and a length of up to 100 mm (previously 12 mm diameter and a length up to 80 mm) inserted though an opening in the protective housing to intercept hazardous radiation;
b)         (for enclosures of Class 4 lasers) an assessment is made of the capability a human hand or arm to intercept hazardous laser radiation. Previously there was no requirement to assess this.
The other condition for gaps remains i.e. the assessment of laser radiation that could be reflected out by a single reflection from a hypothetical flat surface.

Structure
The standard is not now divided into Sections. In the new edition:
Clause 4 still lists the engineering requirements (including 4.2.1 dealing with access during maintenance and 4.12 dealing with "walk-in" enclosures)
Clause 5 specifies the labelling requirements for laser products.
Clause 6 gives the requirements for information including that information for the user and that intended for servicing and for purchasing. 
Clause 7 deals with additional requirements for specific laser products and refers readers to EN 60601-2-22 for medical laser products and EN ISO 11553-1 for laser processing machines.
Clause 8 describes the classification rules and includes direction on the responsibility for classification. 
Clause 9 specifies how accessible emission levels are assessed for the purposes of classification. In this context it should be noted that the Tables of AELs for various laser classes (Table 4 to 9) now provide two tables for each of Class 1/1M, 2/2M and 3R – one where the constant C6 equals 1 (the usual case) and the other for where C6 is greater than one (i.e. extended sources). The interpretations when considering the measurement geometry for extended sources has been expanded, though many on the safety committee feel that this is still not clear and further work is going on to improve understanding.
As the User’s guide has been removed, the requirements within the standard end with Clause 9.  However for information purposes only, MPE values are still included within the standard and are described in Annex A together with the relevant tables (giving MPE limits for various wavelengths and exposure durations). 
There have been no changes to the MPE limits, which are a reflection of the levels specified by the International Commission on Non-Ionising Radiation Protection (ICNIRP).

The future
Will this standard change again? – probably not greatly. There are a few typos, which will need a correction.  There is still concern about the treatment of extended sources and, of course, there is the continual discussion to produce a labelling system that does not require the use of language (a discussion that has been going on for over ten years and seems no nearer to a satisfactory resolution).
There are rumours that MPE levels may be amended by ICNIRP but this is not firm. The current MPE levels are felt to be very conservative and have proved themselves by years of practical application. Test houses are still concerned that the sequence of specification used for the requirements in this standard do not lend itself readily to the sequence of testing and this may influence any further editions of this standard. (Try looking at the checklist specification in IEC TR 60825-5 and the concern in understandable.)
Whatever else, this standard is a worthwhile edition if only for the removal of LEDs from the scope and the final transfer of the user guide to Part 14.