ISSUES OF TECHNICAL REGULATION IN THE FIELD OF PHOTONICS
N.Yu. Malkova 1,2, D. Biol. Sc., firstname.lastname@example.org; V.S. Luginia 3,4, email@example.com
1,FBIS ‘Northwest Scientific Centre of Hygiene and Public Health of Rospotrebnadzor’, St. Petersburg
2FSBEI of Higher Education ‘North-Western State Medical University named after I.I. Mechnikov’, Ministry of Health of the Russian Federation, St. Petersburg
3Baltic State Technical University “VOENMEH” named after D.F. Ustinov, St. Petersburg
4JSC ‘Laser Systems’, http://www.lsystems.ru, St. Petersburg
This paper deals with the issue of technical regulation in the field of laser and LED equipment. The existing documents in the field of laser safety standardization have been considered. Contradictions of the existing schemes of classification of laser devices under the hazard class have been given. The necessity to conduct additional studies of LEDs, and the inclusion of requirements not only to laser devices but to LEDs has been demonstrated based on the analysis of results of separate LED studies. Proposals for forming the Federal Target Program and for the conduct of studies within such program have been provided.
Received: 17.11.2018. Accepted for publication: 28.02.2019
TECHNICAL REGULATION IN THE FIELD OF PHOTONICS
Over 15 years have passed from the moment of adoption of the Federal Law No. 184-FZ as of 27.12.2002 ‘On technical regulation’ (hereinafter ‘Law No. 184-FZ’). The adoption of this Law caused the transition to a new stage in the development of the legislative framework for confirmation of products compliance. However, there are several white spots in the field of technical regulation as of this date. One of them is the technical regulation of photonics equipment.
Law No. 184-FZ establishes that the confirmation of compliance in the territory of the Russian Federation may be voluntary or mandatory. It is obligatory to confirm the compliance of the product with the safety requirements established in the technical regulations. The purpose of product voluntary certification is confirming the compliance of certified products to the requirements of specifications, standards and other documents, the list of which should be determined by the applicant. Actually, the obligatory confirmation of conformity establishes the product safety requirements, and voluntary, quality requirements.
So far, 47 technical regulations have been adopted on the territory of the Eurasian Economic Union. At the same time, none of technical regulations establish requirements ensuring the photonics equipment safety, which contradicts cl. 1 of Art. 7 of the Law No. 184-FZ:
‘1. Technical regulations with regard of the degree of the risk of infliction of harm establish the minimal necessary requirements providing: radiation safety…’
In one sentence, requirements to laser devices are mentioned in cl. 57 of the technical regulations ‘On machinery and equipment safety’:
‘57. At the use of laser equipment, the following conditions should be met:
- accidental radiation should be prevented;
- protection against direct, reflected, scattered and secondary radiation shall be provided;
- absence of danger from optical equipment for laser equipment adjustment monitoring shall be guaranteed’.
It is impossible to say that in absence of technical regulations, the photonics equipment market is not regulated in terms of safety. Vice Versa, the existing regulatory base contains a rather versatile (and sometimes contradictory) set of requirements both to photonics equipment and to processes for such equipment design and operation. The main laser safety regulatory documents are shown on Fig. 1.
Laser safety regulatory base contradictions have been discussed with the sufficient attention to details by various authors [1, 2]. In this article, we will focus only on basic conclusions based on the results of such analysis.
INTERACTION OF LASER RADIATION AND BIOLOGICAL TISSUE
The mechanism of interaction of laser radiation and biological tissue has received sufficient attention in different Russian and foreign publications [3, 4]. All processes characterizing the interaction of laser radiation and biological objects can be divided into three groups. The first group includes all noninvasive processes and processes without any noticeable effect on a biological object; the second group includes processes with photochemical or thermal effects occurring; the third group includes processes causing photo destruction.
—Far and medium spectrum UF area (180-300 nm), far and medium spectrum IR area (1800-105 nm)
—-Close spectrum UF area (300-325 nm), medium spectrum IR area (1150-1800 nm)
—–Close spectrum UF area, close and visible spectrum IR area (325-1400 nm)
The interaction of laser radiation and biological tissue is determined both by radiation source parameters (wavelength, intensity, duration and frequency of pulse repetition, etc.) and biological tissue parameters. Considering the laser radiation absorption by the visual organ, 3 areas can be distinguished (fig. 2). The indicated wavelength boundaries are approximate and depend on the particular person’s biological tissue (eye) properties.
Laser radiation of spectrum UV- and far IR-areas doe not reach the retina. This radiation type is absorbed in the anterior eye part, as a rule, in the cornea or in the crystalline humor. For young persons, due to better optical media permeability, the lower limit of radiation reaching the cornea is in the area of 320 nm. High levels of laser radiation impact can lead to cornea or crystalline humor damage. Intermediate exposure levels in the spectrum UV area cause significant corneal damage, rather serious but temporary.
Skin damage due to laser radiation occurs much less frequently than eye damage. Such damage occurs only in cases when a person works with rather powerful (tens of W/cm2) laser radiation without protective measures.
There is no doubt that laser radiation is both harmful and hazardous influencing factor for human life and health . For radiation safety purposes, technical regulations should be issued according to the requirements of No.184-FZ.
RE-PROCESSING OF LASER SAFETY REGULATORY BASE
Each technical regulation is based on state and interstate standards, which, in their turn, contain product requirements and methods for such requirements evaluation. In the course of the analysis of the existing regulatory framework, the following inaccuracies and contradictions preventing the use of the existing standards in the Technical Regulations can be distinguished.
- Versatility of classification by degree of danger
3 schemes of classification by degree of danger of laser radiation (fig. 3) are valid for the time being on the territory of the Russia Federation.
In terms of harmonization with European standards, the most suitable is the classification given in SanPin 184.108.40.20659-16 and GOST PIEC60825-1-2013. However, it must be kept in mind that SanPin does not contain the binding of a specific hazard class to the laser radiation MAL, which makes the quantification of the degree of laser radiation hazard impossible. When evaluating the hazard class, GOST PIEC60825-1-2013 uses the value of the maximum allowable exposure, which is contrary to SanPin 5804-91 and the procedure for evaluating the hazard degree with regard of MAL. The opinion is known that the difference in the approach to the quantification of the degree of laser radiation hazard under the scheme with regard to the MAL and under the scheme with DEM assessment of DEM considerably reduces the safety level in some wavelength ranges.
- Labeling ambiguity
Among the entire versatility of labeling, the most frequent examples can be distinguished (fig. 4).
In accordance with the ‘status’ of the laser safety regulatory documentation ‘status’, the ‘a)’ labeling is obligatory. ‘б)’ and ‘д)’ labels are not included into the standard requirements and represent the free interpretations by the manufacturer of the markings established in GOST R IEC60825-1. ‘в)’ and ‘г)’ labels visually differ only by the presence of an additional line in the ‘г)’ label.
The requirements not only to label composition and appearance, but also to the places of labeling shield installation and to the minimal size of such shields and the size of warning inscriptions should be established.
- Reduction of standard terminology to common type
No definition exists for the term ‘amplifying optics’. For a person with myopia (D = -3.0), glasses are amplifying optics in terms of physics, but in terms of laser safety, such a person wearing glasses (amplifying optics) will not differ from a person with normal vision in terms of laser radiation impact (in this case, the amplifying optics normalizes vision). At the same time, for a person with normal vision (1.0), a magnifying lens with D = 3.0, similar to the first case, is the amplifying optics and danger when operating the laser device can occur at the use of such amplifying optics under certain conditions.
- Requirements to radiation control
Requirements to radiation control are given only in SanPin 5804-91 and GOST 12.1.031-2010. At this, this requirement is crucial for units of 3 and 4 class. Requirements for the need o establishing the radiation control periodicity, and the requirements to staff performing radiation should be set forth in the technical regulations.
The regulatory document should establish the procedure for staff attestation and access to work with a laser device. The periodicity of assessing knowledge of the safe operation of devices of various classes should be established. When changing the laser equipment technical parameters (e.g., in the case of fundamental design changes), in addition to conducting off-schedule radiation control, requirements for conducting an extraordinary training for safe laser equipment operation should be established.
PHOTOBIOLOGICAL DANGER OF LED SYSTEMS
The regulatory base for LED safety is currently represented in the Russian Federation only by the standard GOST R IEC 62471-2013 ‘Lamps and lamp systems. Photobiological safety’. As a rule, the obligatory confirmation of conformity for such devices is limited to tests in the part of technical regulations ‘On low-voltage equipment safety’ and ‘Electromagnetic compatibility of technical devices’.
In their time, LEDs replaced fluorescent lamps as a relatively safe and energy-efficient light source. At this, a safety criterion was the absence of hazardous materials in the LED composition against the presence of hazardous materials at improper disposal of mercury in a fluorescent lamp. As the scope of LEDs application in industry and in everyday use enhanced, and in terms of LEDs research conducted by separate organizations, new data indicating the potential danger of using the certain LED types started emerging.
Considering the ‘cold light’ LED radiation spectrum, it is possible to note the presence of characteristic intensity maxima in the spectral band of 440-460 nm the most hazardous for the eye (fig. 5) . When the LED is heated to temperatures around 5700 K, the ‘blue spectrum area’ radiation intensity increases.
According to experimental studies results, the negative impact of the LED radiation of blue spectrum area can be divided into two groups:
- photochemical damage of the visual organ and, as a result, an irreversible decrease of visual functions ;
- melatonin synthesis inhibition causing hormonal imbalance and resulting in the emergence of various human diseases .
Certainly, not every LED has such a negative impact. The same as with laser radiation, not only the radiation characteristics but the biological tissue condition (including age: the ‘blue spectrum’ radiation is the most harmful for children’s eyes due to the crystalline humor higher transparency in the dark blue-blue spectrum area) should be taken into account. So For today no fundamental studies of the interaction of radiation of LEDs of different wavelengths and biological have been carried out in Russia. No unified classification scheme has been accepted for LEDs.
Due to the lack of technical regulations relying on LED safety comprehensive research, the market for LEDs and LED systems, similar to lasers and laser systems, is beyond the technical regulation limits.
OFFERS FOR FURTHER WORK IN THE FIELD OF PHOTONICS EQUIPMENT SAFETY
Today, the laser safety standard system is based on studies the most of which were carried out in the 1980ies, with regard of statistical data processing methods and technologies that existed at the time of the study conduct. At this, methods for evaluating the radiation impact on biological tissues, and devices for retinal damage evaluation applied in the 1980s-1990s, are inferior to modern methods and devices in terms of accuracy. Repeated conduct of studies at all points in all ranges is unreasonable, however, confirmation of compliance with the separate objective laws obtained will enable us making a conclusion on the presence of systematic errors in previous studies with a high degree of probability. The results of such studies will specify the existing MALs for various ranges.
In the part of the research base, the following avenues of research can be identified:
- Research of the impact of radiation of peak and femtosecond lasers on biological tissues. Such researches haven’t been conducted before. Initially, ultrashort pulse lasers were used for fundamental physical research, but recently these lasers have been more and more frequently used to solve applied tasks in various fields, for example, in biomedical technologies (laser microinjection, pre-implantation embryo biopsy), and in areas of processing various materials.
- Research of transient ranges of dependence of the maximum allowable energy exposure of eye direct irradiation with laser radiation flows of different wavelengths with the purpose to specify the hygienic reserve for the specified ranges . According to previous experimental results, the areas of approximation ‘breaks’ (10-5-10-3 and 10-10-10-8 sec intervals), the value of the hygienic reserve factor was artificially increased about 3-5 times without physical and physiological reasons. Additional experiments for these areas should be conducted.
- Research of the complex impact of laser and LED radiation on human functional activity. The existing regulatory documents on laser operation contain no requirements for the organization of the safe mode of operation with laser and LED sources. The results of the researches conducted will indicate the necessity (or its absence) for mandatory implementation of preventive and control measures for employees, operating with laser and LED radiation, at enterprises. Without conducting such research, there is no possibility to make a conclusion on the safe mode of operation with such devices. A rather large number of questions on photonics equipment safety are still open or require updating and specification, which makes the conduct of scientific research in the field of photonics equipment safety a topical task. With regard of the volume and complexity of the issues, research can be carried out only in joint cooperation of all the parties concerned.
Laser safety is based on the proposition that for some laser groups, the eye protection is provided by the presence of the corneal reflex (protective corneal reflex time is 0.15-0.25 sec) but the proposition about the corneal reflex duration is based on the inborn reflex at the bright flash (atomic explosion) impact. At the same time, for the collimated laser beam focused into the micrometer spot, no corneal reflex duration has been researched. The respective researches are required to specify the corneal reflex duration at the exposure to laser radiation.
The existing regulatory base is based on research, the volume and degree of topicality of which are insufficient for the development and adoption of the technical regulation ‘On safety of photonics devices’. No consolidated opinion of representatives of the Federal executive authorities, industry, representatives of biomedical organizations and RIs exists on regulatory base to rely on in the development of technical regulations. And with regard of the fact that the minimum technical regulation life cycle from the moment of the project inclusion into the development plan to the adoption of the EEU TR is approximately two years, then, even if we start developing the Technical Regulations now, the adopted technical regulations will see the light no earlier than in 2021. This speaks to the fact that active work with the parties concerned about the creation of Technical Regulations should be carried out already now.
The significance of the issue of photonic equipment safety, the impossibility of its comprehensive solution in short terms due to existing mechanisms, the necessity of interdepartmental and intersectorial cooperation, and the necessity to attract the considerable financing volumes proves that its solution requires the state support in the form of the Federal Target Program (FTP) development and implementation.
The result of the Federal Target Program implementation will be the grounded reforming of the photonics regulatory base and the preparation of the draft technical regulation ‘On the photonics equipment safety’ which will be able to stop legal overreach in the field of photonics. Without carrying out such studies within the FTP (even as in at incomplete research conduct), the revision of the standards will, most probably, turn into a formal procedure, the results of which will present another regulatory document not consistent to the reality but containing a large amount of non-feasible or impracticable requirements.
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©Beawire – May 2019. From magazine PHOTONICS VOL. 13 N 2 2019.