Qualification, certification and approval of UV-LED-Lamps for ...

The technological leap from discharging lamp-based UV-Radiation
sources to LED-based ones in NDT is equal to the change from the
annoying, uncomfortable, unloved, but necessary step-child to the
high-quality, professional and powerful tool
with additional features!!!

Subsequently you will receive information about technological and practical backgrounds as well as the absolute essentials for an appropriate specification, parameterisation, qualification, certification and approval of UV-LED-Lamps for non-destructive testing (NDT), to ensure the necessary inspection quality in fluorescent leak detection.

For more information, please visit our website.

The fluorescent magnetic particle testing (MT) and penetrant testing (PT) are the most powerful NDT-procedures when it comes to finding even the smallest surface defects.

The UV-Radiation source has, amongst other things, a significant role for the error detection as it directly depends on the conformist function and reliability of the UV-Lamp.

If, for instance, the UV-Radiation source does not deliver the necessary intensity in the required wavelength range and in the required &#;technical&#; quality, relevant indicators will not become visible and the inspector misjudges the faulty, highly critical safety parts and constructions as error-free as he cannot see the real existing indicators.

The quality of the UV light source is of fundamental importance for an optimised, safe, reliable and inexpensive audit.

The non-destructive, fluorescent testing is the by far most demanding area of application for UV-LEDs, as a malfunction of the lamp can barely be noticed by the inspector, error indicators do not become visible and no further instance reviews the testing process.

Perfectly adapted UV-LED luminaire systems can not only drastically improve the testing process as well as the working conditions, but also offer a long-term reduction in costs and drastically improve the work safety.

You can find a compact overview by Marc Breit in the NDT-Newspaper 139 by the German Society for Non-Destructive Testing (DGZfP).

Download the specialist article specialist article in the NDT-Newspaper (April ) (PDF) or read it directly on the DGZfP Website.

In the upcoming weeks you will be receiving further details, information and explanations behind the links between the individual paragraphs all about the topic of UV-LED-Technology in NDT.

Should you have any questions on short-call, need any information or support, do not hesitate to contact RIL-CHEMIE through the above-mentioned contact details.

You can find a compressed overview of the most important sections for the inspectors in the chapter:
The most important information for auditors and inspectors

I. Basic Information

a. The testing practice and the currently mild standards (State 5/)

b. Technical basics of the fluorescent magnetic particle testing (MT) and penetrant testing (PT)

c. Top priority of fluorescent leak detection processes in NDT:
optimum, high contrast perceptibility of indications for the human eyesight

d. The human eyesight

e. Technological and optical requirements for light and radiation sources for visual evaluation

f. What is UV-A-Radiation and visible light?
The spectral emission of a lamp and its importance for fluorescent leak detection

g. Risks associated with the usage of inadequate UV-Lamps

h. Responsibility for the fulfilment of the requirements and liability of the auditors

i. Practical- and occupational safety risks using traditional UV-Radiation sources

II. The change in technology from the simple discharge lamp (mercury-vapour lamp, xenon-lamp, metal halide- or halogen burner) to semiconductor UV-LEDs as a radiation source for NDT and its meaning for the testing process.

a. The difference between a simple electronic device and an electronic system

b. Quasi standard in bulb-based lamps and the compelling necessity of an extensive qualification and parametrisation of UV-LED-Lamp systems

c. technical basics of LED-Technology

d. Characteristics of using UV-LEDs

e. Requirements for UV-LED luminaire systems for NDT

f. Parameters to describe and specify UV-LED-Lamps

g. UV-Intensity-Stabilisation: a simple parameter to check that gives a clear indication about the quality of the UV-LED, its lifetime as well as wavelength stability, practicability, processing quality and condition of the overall system.

III. Advantages using adequate UV-LED-Radiation sources in fluorescent crack detection

a. General advantages of LED-Technology

b. Technical advantages of LED-based UV-Radiation sources

c. Practical advantages of using high quality UV-A-LED-systems

d. Advanced functionality that only just becomes available through LED-Technology

e. Extended occupational safety

f. Commercial advantages when using optimised UV-LED-Technology instead of traditional discharge lamp-based UV-Lamps

g. Additional advantages when using UV-LED-Lamp-Systems with secu-chek®-Technology by RIL-CHEMIE

IV. Relevant parameters to describe UV-LED-Sources for NDT

a. UV-Intensity

b. Spectral emission

c. Visible emission and white light proportion

With competitive price and timely delivery, AJR sincerely hope to be your supplier and partner.

d. UV-Intensity-Stability, degradation and lifetime

e. Minimum working distance

f. Uniform distribution of radiation

g. Intensity behaviour at the edges

h. Perceived and illuminated area

i. Allowed operating conditions

j. Recommended operation purpose

k. Constancy and residual ripple of UV-Radiation

l. Maintenance and overhaul cycles

m. Number of LEDs

V. Requirements for the qualification and specification of UV-LED-Lamps for NDT

a. Type testing and sample inspection

b. Testing every individual lamp

c. Specification and certification through the manufacturer

d. Qualification and approval of the UV-LED-Lamp for the specific application and testing requirements through the testing responsible person.

e. Working ergonomics and stress-free vision

f. Why only flicker-free, non-pulsing UV-LEDs with minimal residual ripple are acceptable

VI. State of the standardisation (Beginning of )

a. DIN / EN / ISO (Foundation for DIN / EN / ISO (MT) and DIN / EN / ISO (PT))

b. ASTM / AMS / SAE (American standardisation)

c. NADCAP (Accreditation for suppliers of the aviation industry)

d. AIRBUS

e. MTU Aero Engines

f. Rolls-Royce and ADS SIG NDT UK

g. Pratt & Whitney (P&W)

h. General Electric Aviation (GE)

i. SAFRAN Group (Turbomeca, Snecma. Hispano-Suiza)

VII. Tabular comparison between the new and the old technology

Protection Notice:

This technical information and the content of this website and the following ones are intellectual property of RIL-CHEMIE Marc Breit.

The usage, exploitation, publication and sharing of the content or parts thereof is prohibited if not explicitly stated otherwise. In the event of contraventions compensation for damages will be claimed. All rights for designs, registered designs or industrial designs are reserved for RIL-CHEMIE Marc Breit.

© RIL-CHEMIE Marc Breit

Introduction 

Thanks to the technological advancement, more and more inventions have arose and leverage our living standard. However, technology is a double edged sword that creates both advantages and disadvantages. Illustrating with the instance of UV NDT lamps and UV LED lamps, the invention of UV lamps has greatly enhanced the efficiency and ease of leak detection and fluorescence observation. However, due to their high intensity, a long exposure under the light can result in several health hazards. Accordingly, technicians should follow a set of strict guidelines in order to maximise the effectiveness of the technology while securing their own safety and health. 

Definition of UV Light

Ultraviolet (UV) light has a relatively shorter wavelength than visible light. It belongs to a type of electromagnetic waves, which carry pure energy with the characteristics of moving quickly and travelling through empty space. Considering its higher frequency than visible light, a larger energy is stored in it, meaning a greater ability to penetrate to human skin, resulting in a potential danger. 

Potential Danger of UV Light

Depending on the duration of exposure and the wavelength, UV light can be associated with diverse health effects. The most common instance is skin-related problems, for instance, skin pigmentation, sunburn and most seriously, skin cancer. There may also be various visual hazards. In particular, under the exposure of UV-C (100 &#; 280 nm) and UV-B (280 &#; 315 nm), corneal injuries and erythema may be resulted, while for UV-A (315 &#; 400 nm), the potential consequences include cataracts and retinal burns, causing severe physical harm. 

Guidelines of Exposure to UV Light 

In view of the potential health hazards of UV NDT lamps and UV LED lamps, a Threshold Limit Values (TLVs) of occupational exposure to UV is issued by the American Conference of Governmental  Industrial Hygienists (ACGIH). Specifically, it refers to the wavelength of 180 to 400 nm. Within this range, workers can be repeatedly exposed without resulting in health damage. For wavelengths exceeding this range, adequate guidelines must be followed to safeguard workers&#; health. For instance, a polycarbonate face shield with a certification must be worn to protect both the face and eyes. On top of the face shield, UV certified googles or safety glasses should also be worn to avoid visual hazards. When dealing with some tasks requiring an uplifting intensity of UV light, the length of working hours may also be limited. Correspondingly, workers should be clear about the intensity of wavelength generated by the equipment in order to understand its effects and be equipped with appropriate protective gear. Furthermore, concerning the  photosensitivity generated, people taking certain types of drugs should avoid any exposure to UV light. 

Advantages of UV Light 

By following the proper procedures and strict guidelines when using the UV NDT lamps or UV LED lamps, they can generate multiple advantages in diverse fields. Both the SL and SL UV LED Lamp series carry LEDs with an intensity of 365 nm. On average, they can produce an irradiated area of 100 to 260 mm. Given their high fluorescence stimulation, the insignificant traces can be highlighted and become highly visible even in daylight. In spite of their high intensity, the amount of visible light emission is maintained at a minor level, thus minimising its influence on the illumination result. In addition, the design of variable focal length adjustment produces a more precise intensity, while the installation of a focus ring enhances the convenience of operation, particularly in poorly accessible areas. Therefore, taking the high and flexible intensity and a long lifespan of   hours into account, the UV NDT lamps and UV LED lamps are widely applied in plenty of aspects, consisting of leak detection in buildings, forensics, non-destructive testing of materials, etc. 

Conclusion

The innovation of UV NDT lamps and UV LED lamps has created countless benefits in numerous industries. However, to optimise their performance while not causing any harm to the technicians, clear guidelines and instructions should be provided by companies to draw their attention to the potential health hazards of UV light. Thereby, the instance of UV light has highlighted the significance of formal operation in maximising the advantages of different technologies. 

(700 words) 

For more information, please visit Ndt Uv LED Lamp.