IEC TR 62471-2 pdf download – Photobiological safety of lamps and lamp systems – Part 2: Guidance on manufacturing requirements relating to non-laser optical radiation safety

IEC TR 62471-2 pdf download – Photobiological safety of lamps and lamp systems – Part 2: Guidance on manufacturing requirements relating to non-laser optical radiation safety
4Risk groups applied for optical radiation safety assessments
4.1 Basis for optical radiation safety classification
IEC 62471 provides the method to determine the risk group of any lamp or any productincorporating a lamp. The risk groups in IEC 62471 indicate the degree of risk from potentialoptical radiation hazards and minimise the need for further measurements. The risk groupswere developed based upon decades of lamp use experience and the analysis of accidentalinjuries related to optical radiation emission (where injuries were, generally, quite rare exceptfrom ultraviolet-emitting lamps or arc lamps).There are four basic risk groups:
Exempt Group (RG 0)， where no optical hazard is considered reasonably foreseeable,even for continuous,unrestricted use. Typical examples are most frosted incandescentlamps and fluorescent lamps used in domestic applications;
Risk Group 1 (RG 1) products are safe for most use applications，except for veryprolonged exposures where direct ocular exposures may be expected. An example of aRisk Group 1 product is a domestic battery operated torch (flashlight);
Risk Group 2 (RG 2) products generally do not pose a realistic optical hazard if aversionresponses limit the exposure duration or where lengthy exposures are unrealistic;
Risk Group 3(RG 3) products pose a potential hazard even for momentary exposures,andsystem safety requirements are generally essential.
IEC 62471 does not provide manufacturing requirements and control measures.These issuesshould be addressed in application-specific vertical standards (see 4.3.3).However,in orderto provide a consistent approach across products,the (non-normative) labelling requirementsare outlined in this technical report (see 5.4).
4.2Assessment criteria
The standard measurement conditions consider the emission spectrum and, depending on thetype of hazard，either irradiance or spatially averaged radiance to determine risk to the eyeand/or the skin.The measurement conditions are related to potentially hazardous viewingconditions and take into consideration physiological factors of the eye，such asaccommodation, pupil size,the aversion responses and eye movements (saccades).
IEC 62471 distinguishes between lamps intended for general lighting service (GLS) and lampsintended for use in other applications such as for germicidal use,heating,signalling,datatransfer or others. Assessment and measurement conditions are different for these twogroups:
. GLs – the hazard values should be quoted as irradiance or spatially averaged radiance
values at a distance which produces an illuminance of 500 lux;
. other applications – the hazard values should be determined at a distance of 200 mm from
the source.
Different application groups define a range of operational，maintenance and servicingconditions. lf the assessment applied to different application groups in a vertical standardjustifies it, the measurement conditions in lEC 62471 can be modified for specific applicationgroups.
4.3Application-related issues4.3.1 Near-infrared sources
The limits set for the infrared (IR) spectral region were originally intended for applications oflarge lR-radiators with a significant amount of lR-A and lR-B radiation.The limits protect thecornea or lens of the eye against long-term thermal effects (e.g. cataract).Thus，the limitsshould be applied where the application is likely to result in chronic and lengthy exposures of
the eye for periods greater than 1 000 s and the daily averaged irradiance is expected to be atleast 100 w-m-2.The primary objective is to minimise heating of the lens and cornea.
4.3.2“Point sources”
There may be a small number of applications where an incoherent optical radiation sourceappears as a nearly monochromatic”point”source and should be considered within a lasersafety standard framework.Generally, this will only apply to: superluminescent diodes(SLDs)(see 3.16),which resemble “point sources”; and LEDs which are employed in optical fibrecommunications，where the fibre source also resembles a very small, or“point” source.Theuser is referred to lEC 60825-1 for SLDs and to lEC 60825-2 for optical fibre communicationsystems.
4.3.3Application-related vertical standardsThe requirements in vertical standards may:
– limit the source risk group that can be used in a given application;
– require specific performance features based upon the risk group specifications; or- specify application-specific control measures.
Basic guidance,based on the likelihood of direct source viewing,is provided in Clause 6.Vertical standards should be guided by the principle that it is not necessary to reduce opticalradiation exposure to as low as reasonably achievable. However,as a general guideline,needless emissions that would produce unnecessary human exposure should be minimised.The hierarchy of applicable safety measures should follow the internationally accepted priorityranking of manufacturer safety measures.That is, engineering controls (e.g., filters, shielding,etc) are the highest priority， followed by administrative measures (such as warnings andlabels,see 5.4) and then personal protective equipment as the last resort. Details should beprovided in application-specific vertical standards.
5Guidelines for lamp and lamp system manufacturers on how to apply lEC
62471
5.1 Limit values5.1.1General
lt should be noted that the risk group classification system of lEC 62471 is primarily applied tolamps.However,in terms of product safety, the lamp system manufacturer has responsibilityfor assessing the final lamp system product.Because of different technical tasks and needs,manufacturers of lamp systems or luminaires might have limited capabilities for tests andmeasurements and they commonly rely on the lamp/LED data provided by the lamp/LEDmanufacturer.Therefore,guidance is provided on how and when lamp system manufacturersmay rely on data provided by the lamp manufacturer.