Frequently Asked Questions
Blog | 13.03.18
Is my mercury vapor light in compliance with ASTM E3022-18? No. ASTM E3022-18 is only applicable for UV-A LED lights. It is not applicable for mercury vapor, gas-discharge, arc or luminescent (fluorescent) lamps or light guides (for example, borescope light sources).
Is my mercury vapor light in conjunction with an LED replacement bulb in compliance with ASTM E3022-18? No. It is the responsibility of the manufacturer to certify a specific UV LED lamp as a single unit, taking into consideration ALL the parts that make up the light such as the housing, filter, diodes, electronic circuit design, optical elements, cooling system, and power supply combination. When you buy one of the above components, in this case the diodes, there is no guarantee that use of the diodes with any mercury unit will not shift the wavelength of the diodes outside the 360-370nm region. Nobody tested the body with the diodes and therefore nobody can claim compliance with ASTM E3022-18.
If my certificate says E3022-15, should I ask for a certificate which says E3022-18? No. There is no need. The difference between E3022-15 and E3022-18 is just a conversion factor that was corrected. Nothing fundamental has changed in E3022-18 that should be part of your certificate.
I have lost my ASTM E3022-18 certificate, can I get a copy? Although the standard does not refer to storage of data, all major manufacturers store the data to reproduce your certificate. Labino does that for free.
Can I repair my UV light on my own? It depends what is broken. If it is something unrelated to the optical output such replacing the PSU or an external cable, so long as you are qualified and/or authorized by your company, you can repair it. However, the burden and most often the knowledge, of making a light perform in accordance with ASTM E3022-18 lies with the manufacturer (Sect. 1.2). A certification is an action that requires several hours to complete, requires specialized equipment (for example a spectrometer) and an excellent interpretation of the standard. Repairs relating to the optical performance of the light must be left to the manufacturer or an authorized service center.
When does my UV LED light needs re-certification? A light should be re-certified by the manufacturer or an authorized service center of the manufacturer only. The re-certification is required only if a critical component that affects the performance of the light is damaged. Such components are typically components that are inside the housing such as a failing LED, a burned drive card etc. No re-certification is needed if you need to replace components external to your light such as your power supply unit, a power cord, or batteries.
What is the difference between a Type Test and a Unit Test report? A Type Test report is a very detailed and comprehensive report that each manufacturer makes on a specific model using a reference light (not the light sold to you) within that model. The reference light is stored safely and should be made available in case of an audit. A Type Test report should be made available to users upon request. A unit test report records tests that are made on the light that users have purchased. A unit test report should be included with your light.
Who regulates implementation of the ASTM E3022-18 standard? Nobody. ASTM E3022-18 tests and measurements are made by the manufacturers for their own products. It is therefore necessary to choose a credible manufacturer before you make an investment. Specific sections of the standard are audited by Nadcap and/or ISO auditors. ASTM E3022-18 is referenced and adopted by all major NDT procedures such as ASTM E1444 (Standard Practice for Magnetic Particle Testing) and ASTM E1417 (Standard Practice for Liquid Penetrant Testing).
What do I do if I operate a light with several UV LEDs bundled together in the same position and I cannot see if any have failed? ASTM E3022-18 does not comment on how LEDs should be positioned or how many they should be, so long as all the acceptance tests are met. However, one drawback with UV LEDs positioned together is that you cannot see if any failed, especially since there is a filter covering them. You will only know if you measure the UV output and detect a sharp drop in intensity. Testing equipment should be controlled, and failures detected.
My company has two different digital UV-A meters that show different readings each. Why? Check if your units have been recently calibrated from an ISO 17025 calibration lab or equivalent, with Scope of UV and White Light measurements. An ISO 17025 calibration lab is not qualified to calibrate everything. Check if the UV sensor diameter is greater than 0.5 inches (12.7 mm). This might explain the extra error. The UV sensor diameter should not be greater than 0.5 inches (12.7 mm). Both requirements are part of the ASTM E3022-18, Section 6.1: “Ultraviolet radiometers shall be calibrated in accordance with ANSI/ISO/IEC 17025, ANSI/NCSL Z540.3, or equivalent. Radiometers shall be digital and provide a resolution of at least 5 µW/cm2. The sensor front end aperture width or diameter shall not be greater than 0.5 in. (12.7 mm).”
Why do my old analog meters not measure the same for a UV-A LED light versus a Mercury UV-A light? The answer is simple. Mercury UV-A lights emit a lot of light in wavelengths away from 365 nm and many old meter models were not designed to handle large concentration of light around a specific wavelength. UV LED lights emit a lot of light around 365 nm. Irradiance coming out of a UV LED lamp is best measured with a digital meter. Digital UV radiometers for NDT are made with a filter and a detector. The detector is measuring ALL the light that gets transmitted through the filter, typically around the 365nm area.
Are there any safety concerns from the use of UV-A LED lights? UV lights can be harmful to the eyes and skin and protection should be proportionate to the associated risk, as NOT all UV lights are the same. Injuries and blindness can be the result of exposure to ultraviolet (UV). Lights sold in Canada, the European Union and some Asian countries are required to be tested to the IEC 62471 standard. The equivalent standard in the United States is ANSI/IESNA RP-27. These two standards are similar in context and provide guidance for evaluating the photobiological safety of lamps. Specifically, they define exposure limits, reference measurement techniques and the classification scheme for the evaluation and control of photobiological hazards from sources of optical radiation, including LEDs, in the wavelength range from 200 nm through 3000 nm. Any UV LED manufacturer that claims the CE mark should have these tests taken.