GB 7247.1-2012Safety of laser products - Part 1: Equipment classification and requirements (English PDF)

1 Scope

The part applies to the safety of laser radiation from laser products whose emission lies in the wavelength range from 180 nm to 1 mm.

A laser product may be a single laser with or without a separate power supply, or a complex optical, electrical or mechanical system fitted with one or more lasers. Laser products are used for the demonstration of physical and optical phenomena, for material processing, for data reading and storage, and for the transmission and display of information; systems of this kind are already used in industry, commerce, entertainment, research, education, medicine and consumer products.

Laser products sold to other manufacturers for use as system components need not comply with the part, because the end product itself will be subject to it. If, however, the laser system inside a laser product is operable equipment once separated from the equipment, the unit that has been removed shall meet the requirements of the part. Note 1 adds that operable equipment needs no tools to be made ready for operation.

Where a manufacturer produces laser products classified in accordance with Clause 3, Clause 8 and Clause 9, the requirements of the part need not be considered, the emission level of the laser product under all conditions of operation, maintenance, service and failure not exceeding the accessible emission limit of Class 1. The acronym is printed at this point as “ALE”, whereas 3.3 and the rest of the text use “AEL”. Note 2 states that the exemption above is meant to keep laser products that are inherently safe free from the constraints of the standard.

Besides the hazards caused by laser radiation, laser equipment can cause other injuries, such as fire and electric shock. Note 3 restricts the classification and the other requirements of the part to the hazard that laser radiation presents to the eyes and the skin; other hazards are not included in its scope.

The part states minimum requirements. Compliance with it may still not be enough to reach the required level of product safety: a laser product has to satisfy the performance and test requirements of the corresponding product safety standard. Note 4 observes that other standards may carry further requirements and that the intended application and the user group are to be considered — a Class 3B or Class 4 laser product, for instance, is not suitable for use as a consumer product.

If a laser system forms part of an equipment, the equipment has to comply with the other IEC product safety standards, such as those for medical equipment (IEC 60601-2-22), information technology equipment (IEC 60950), audio and video equipment (IEC 60065), equipment used in hazardous environments (IEC 60079) and electronic toys (IEC 62115). Under the terms of IEC Guide 104, cited in a footnote as IEC Guide 104:1997 on the preparation of safety publications and the use of basic safety publications and group safety publications, the part applies to the hazards caused by laser radiation. Where no applicable product safety standard exists, IEC 61010-1 is to be used.

In earlier editions LEDs (light-emitting diodes) were within the scope of IEC 60825-1, and they are still included in other parts of the IEC 60825 series. With the development of lamp safety standards, however, the optical radiation safety of LEDs is generally better laid down in a lamp safety standard. Removing LEDs from the scope of the part does not prevent other standards from including LEDs where laser products are concerned. CIE S009 may be used to determine the hazard classification of an LED or of a product that contains one or more LEDs.

The MPE (maximum permissible exposure) values of the part apply to laser radiation only and not to accompanying radiation; where an operation involves accessible hazardous accompanying radiation, the MPE values for laser radiation may be used to make a prudent assessment of that potential hazard. MPE values do not apply to laser exposure used on patients for medical treatment or for cosmetic purposes on the human body. Note 5 presents Annex A to Annex G as general guidance with many typical examples, to be taken as reference material for the corresponding clauses of the part rather than as definitive or exhaustive.

The stated purposes of the part are: to introduce a system that classifies lasers and laser products by the degree of hazard of their optical radiation, so as to help in hazard assessment and to help users determine control measures; to establish requirements on the manufacturer to supply information, so that proper precautions can be taken; to make sure, through labelling and instructions, that warning can be given of the various hazards associated with the accessible radiation of laser products; and to reduce the possibility of injury by minimizing unnecessary accessible radiation and by improving the control of laser radiation hazards through protective measures.

2 Normative references

The documents listed are indispensable for the application of the document. For dated references, only the edition cited applies; for undated references, the latest edition, including all amendments, applies.

Three documents are cited: IEC 60050-845:1987, International Electrotechnical Vocabulary (IEV) — Chapter 845: Lighting; IEC 60601-2-22, Medical electrical equipment — Part 2: Particular requirements for the safety of diagnostic and therapeutic laser equipment; and IEC 61010-1, Safety requirements for electrical equipment for measurement, control, and laboratory use — Part 1: General requirements.

3 Terms and definitions

The terms and definitions given in IEC 60050-845 and the ones below apply to the document; for convenience, some of the terms and definitions of IEC 60050-845 are repeated here.

A note explains that all definitions are arranged in the alphabetical order of the English terms. Where a definition departs from IEC 60050-845 the difference is marked, and in that case the reference is placed in brackets with the wording “modified”, following the explanation given in the corresponding part of IEC 60050-845.

3.1 access panel: the part of a protective housing or protective enclosure that, when removed or displaced, gives a path to laser radiation.

3.2 accessible emission: the radiant quantity determined in accordance with Clause 9 at a given position, using an aperture stop (with the AEL in watts or joules) or a limiting aperture (with the AEL in watts per square metre or joules per square metre). As provided in definition 3.37, accessible emission is determined only where persons can gain access. To determine the class of a laser product, the accessible emission is compared with the accessible emission limit of definition 3.3; the term “emission level” used in the body of the standard is to be understood as accessible emission. A note adds that, when the laser beam diameter is larger than the aperture stop, the accessible emission given in watts or joules is smaller than the total emitted power or energy of the laser product; and that, when the laser beam diameter is smaller than the diameter of the limiting aperture, the accessible emission given in watts per square metre or joules per square metre, that is the irradiance or radiant exposure averaged over the limiting aperture, is smaller than the actual irradiance or radiant exposure of the laser beam. The note refers to aperture stop (3.9) and limiting aperture (3.52).

3.3 accessible emission limit; AEL: the maximum accessible emission permitted within a particular class. A note explains that wording such as “emission level not exceeding the AEL” in the text means that the accessible emission is measured following the test criteria specified in Clause 9.

3.4 administrative control: a non-engineering safety measure, for example key supervision, safety training of personnel, warning measures, countdown procedures and on-site safety control.

3.5 alpha min, written as alpha with the subscript min: see angular subtense and minimum angular subtense (3.7 and 3.58).

3.6 angle of acceptance, symbol gamma: the plane angle over which a detector responds to optical radiation, generally measured in radians. The size of the angle of acceptance can be controlled by an aperture or an optical element placed in front of the detector (see Figure 3 and Figure 4). The angle of acceptance is sometimes also called the field of view.

3.7 angular subtense of the apparent source, symbol alpha: as shown in Figure 3, the angle subtended by the apparent source as seen from a point in space. Note 1: the position and the angular subtense of the apparent source depend on the position of observation within the beam (see 3.11). Note 2: in the part, the angular subtense of the apparent source applies only in the retinal hazard region of the wavelength range from 400 nm to 1 400 nm. Note 3: the angular subtense of the source is not to be confused with the beam divergence; it can never be larger than the beam divergence and is usually smaller than it.

3.8 aperture (window): any opening in the protective housing or other shield of a laser product through which the laser radiation emitted allows persons to gain access. See also limiting aperture (3.52).

3.9 aperture stop: the opening used to define the area through which the radiation to be measured passes.

3.10 apparent source: the real or virtual emitter that, at the position given for the assessment of retinal hazard, can form the smallest image on the retina, the accommodation range of the human eye being taken into account. Note 1: the accommodation range of the eye is assumed to be variable from 100 mm to infinity; for a given observation position within the beam, the position of the apparent source is the position that corresponds to the condition of greatest retinal radiation hazard to which the eye accommodates. Note 2: the definition is used to determine the position of the apparent source of laser radiation in the wavelength range from 400 nm to 1 400 nm at a given assessment position. In the limiting case of zero divergence, that is an ideal collimated beam, the position of the apparent source is at infinity.

3.11 beam: laser radiation characterized by its direction, divergence, diameter or scanning characteristics. Diffuse radiation produced by a non-specular reflection is not treated as a beam.

3.12 beam attenuator: a device that reduces laser radiation to a specified level or below it.

3.13 beam diameter; beam width, symbol d with the subscript u: the beam diameter d-u at a point in space is the diameter of the smallest circle whose power (or energy) is u percent of the total laser power (or energy). The part uses d with the subscript 63. Note 1: for a Gaussian beam, d-63 corresponds to the point at which the irradiance (radiant exposure) has fallen to 1/e of its peak value at the centre. Note 2: the second-moment diameter definition, given in ISO 11146-1, is not used for laser beams whose profile has a high central radiance peak on a low background, such as the far-field laser beam produced by an unstable resonator; when the second moment is used and the power is calculated assuming a Gaussian beam profile, the power passing through the aperture is significantly underestimated.

3.14 beam divergence, symbol phi: the far-field plane angle of the cone defined by the beam diameter. If the beam diameters at two points a distance r apart (see 3.13) are d-63 and d-63 prime, the divergence of the beam is expressed by Formula (1). In the legend of the formula, phi is the beam divergence, d is the beam diameter and r is the distance between the two points; the SI unit is the radian. The equation itself is not reproduced here. A note repeats that the second-moment divergence definition, given in ISO 11146-1, is not used for laser beams whose profile has a high central radiance peak on a low background, such as the far-field laser beam produced by an unstable resonator, whose profile shows the diffraction pattern caused by the aperture.

3.15 beam expander: a combination of optical elements that increases the diameter of a laser beam.

3.16 beam path component: an optical part placed in the specified beam path, for example a beam-turning mirror or a focusing lens.

3.17 beam stop: a device that terminates the path of a laser beam.

3.18 Class 1 laser product: a laser product for which, during operation, the laser radiation to which persons are exposed at the corresponding wavelength and emission duration is not permitted to exceed the Class 1 accessible emission limit (AEL) (see 8.2 and 8.3 e)). Note 1 refers to the restrictions in the classification table of Annex C. Note 2 warns that, since the tests that determine the class of the product are limited to conditions of operation, an embedded laser product may, depending on the product, give access to radiation above the Class 1 AEL during maintenance, when the interlock of an access panel is released.

3.19 Class 1M laser product: a laser product for which, in the wavelength range from 302.5 nm to 4 000 nm and during operation, the accessible laser radiation to which persons are exposed at the corresponding wavelength and emission duration is not permitted to exceed the Class 1 accessible emission limit (AEL) (see 8.3 e)), the emission level being measured in accordance with 9.2 g). Note 1 refers to the restrictions in the classification table of Annex C. Note 2 observes that, because a smaller measurement aperture than the one used for Class 1 laser products is adopted, or because the emission level is assessed at a greater distance from the apparent source, the output of a Class 1M laser product is potentially hazardous when it is viewed with an optical instrument (see 8.2). Note 3 repeats, for the Class 1M AEL, the maintenance warning already given in 3.18.

3.20 Class 2 laser product: the definition begins on the last page available and is cut off there. What can be read places it in the wavelength range from 400 nm to 700 nm, during operation, at the corresponding wavelength and emission duration, for the accessible laser radiation to which persons are exposed. The remainder of the definition, and the definitions from 3.21 onwards, lie beyond the pages read.

Relationship to previous standards

The document replaces GB 7247.1-2001, Safety of laser products — Part 1: Equipment classification, requirements and user's guide. The foreword lists the successive editions of the standard it replaces as GB 7247-1987, GB 7247-1995 and GB 7247.1-2001.

GB 7247, Safety of laser products, is divided into Part 1, Equipment classification and requirements, and Part 14, User's guide; the document at hand is Part 1. It was drafted according to the rules given in GB/T 1.1-2009.

Among the main technical changes with respect to GB 7247.1-2001 the foreword lists: the removal of the section on light-emitting diodes (LEDs); the addition of the terms accessible emission, angle of acceptance, beam, Class 1M laser product, Class 2M laser product, limiting angle of acceptance for the assessment of retinal photochemical hazard, limiting angle of acceptance for the assessment of thermal hazard, maximum restricted position, photochemical hazard limit, small source, thermal effect hazard limit and time base; the removal of the terms collimated laser product, laser fibre optic transmission system, levelling laser product, service connector and surveying laser product; the change of the term “window; aperture stop” from one entry into two; the modification of the general requirements for the protective housing and of the content on access panels and safety interlocks, laser radiation emission warning, scanning safeguard and walk-in access; the addition of manual reset; the removal of the collimating aid; the changes to the labelling clauses and to the information for the user; the addition of the other parts of the IEC 60825 series, of laser processing machines, electronic toys and consumer electronic products; the removal of laser fibre optic transmission systems; the move of classification from Clause 9 to Clause 8; the change of tests into the determination of the accessible emission level, moved from Clause 8 to Clause 9; the removal of the user's guide part; the addition of the maximum permissible exposure as Annex A; the revision of the calculation examples, with classification examples added and the maximum permissible exposure examples removed; the addition of class descriptions and potential associated hazards as Annex C; the revision of the biophysical principles; the addition of MPEs and AELs expressed in radiance as Annex E; the change of the appended tables into summary tables; the addition of the list of the related parts of IEC 60825 as Annex G; and the removal of the content on high-power lasers for laser products used for material processing and of the list of related standards.

The foreword also lists the Chinese documents that correspond to the international documents referenced normatively: GB/T 2900.65-2004, Electrotechnical terminology — Lighting (IEC 60050-845:1987, MOD); GB 4793.1-2007, Safety requirements for electrical equipment for measurement, control and laboratory use — Part 1: General requirements (IEC 61010-1:2001, IDT); and GB 9706.20-2000, Medical electrical equipment — Part 2: Particular requirements for the safety of diagnostic and therapeutic laser equipment (IEC 60601-2-22:1995, IDT).

Adoption, status and administration

The foreword states that Clause 3 and Annex A to Annex G of the part are recommendatory and that the remaining clauses are mandatory.

The part adopts IEC 60825-1:2007, Safety of laser products — Part 1: Equipment classification and requirements (English version), identically, by the translation method. The foreword records that the relationship between the IEV and the IEC is not mentioned in the English version of IEC 60825-1:2007 and that the Chinese text is the same as that English version. One editorial change is declared: the foreword of IEC 60825-1:2007 has been deleted.

A note in the front matter states that some of the content of the document may be covered by patents and that the issuing body takes no responsibility for identifying them.

The part was proposed by the China Machinery Industry Federation and is under the jurisdiction of the National Technical Committee on Optical Radiation Safety and Laser Equipment of Standardization Administration of China (SAC/TC 284). The drafting organizations recorded in the foreword are the Beijing Institute of Optoelectronic Technology, the Beijing Laser Metrology and Testing Centre and the 11th Research Institute of China Electronics Technology Group Corporation; the main drafters are Wu Aiping, Lu Yonghong, Duan Zhenguang, Li Jialun and Qi Yan.

The document was issued on 31 December 2012 and took effect on 25 December 2013.

Note on the printed English terms

The English title on the cover page is printed as “Safety of laser products — Part 1: Equipment classification and requirements” and is reproduced here with the spacing normalized; no word has been changed.

Two English terms inside the list of definitions carry printing errors and are given above in their corrected form. In 3.6 the term is printed “angle of accepance”, for “angle of acceptance”. In 3.20 the term is printed “Class 2 lase product”, for “Class 2 laser product”.

In Clause 1 the accessible emission limit is printed as “ALE”, while 3.3 and the rest of the text use “AEL”. The reading was confirmed on an enlargement of the scan; the acronym has been left as printed in the paragraph that reports it, with the discrepancy stated.