What are the tests required for each model?
Blog | 17.09.20
Tests on the lamp model (referred to as Type Test Report) must be made available to users by the UV lights manufacturer. The manufacturer cannot claim compliance by only supplying a unit test report and not making available the measurements required on the lamp model.
A Type Test report is a very detailed and comprehensive report that each manufacturer is obligated to make on a specific model using a reference light (not the actual light sold to you) of that same model. This is part of the process to claim compliance. The reference light is stored safely and should be made available in case of an audit. If you are the owner of a Labino UV light, regardless if you are an individual or company, Labino doors are open for you to visit us with your quality management and/or NDT team, audit us and remeasure the values included in the type test report with our reference light.
If you buy a UV LED light that is labeled to have been tested for compliance with ASTM E3022-18, you have the right to ask the manufacturer for this report.
List of Tests Required for every Lamp Model – Type Test Report: Maximum Irradiance, Peak Wavelength, Beam Irradiance Profile, Full Width Half Maximum (FWHM), Minimum Working Distance, Longest Wavelength at Half Maximum, Temperature Stability, Excitation Irradiance, Maximum Housing Temperature, Current Ripple, Emission Spectrum, Filter Transmittance.
The above tests are not just a number each. Each measurement is derived through a process that requires multiple actions taken over several hours and specialized equipment to make these measurements possible. For example, the Ambient Temperature Test (Section 7.6.2) that falls under Temperature Stability (Section 7.6) states: “At lamp switch-on, perform the measurements deﬁned by 7.6.4 (emission spectrum measurements). Repeat the measurements every 30 min until the peak wavelength varies by no more than ±1 nm and the excitation irradiance does not vary more than 5% over three consecutive measurements. Once stabilized, measure the current ripple”.
The Elevated Temperature Test (Section 7.6.3) that also falls under the Temperature Stability (Section 7.6) requires use of a climate chamber to artificially elevate the temperature around the light. The standard states in relation to the test (Section 184.108.40.206): “Set the chamber temperature to the maximum manufacturer’s speciﬁed operating temperature of the lamp. At lamp switch on, perform the measurements deﬁned by 7.6.4 (emission spectrum measurements). Repeat the measurements every 30 min until the peak wavelength varies by no more than ±1 nm and the excitation irradiance does not vary more than 5% over three consecutive measurements. Once stabilized, measure the current ripple”.
UV Lights are classified by the standard in three categories:
(a) Type A – These are UV-A lights powered by AC (Mains) and correspond primarily to handheld and overhead applications (i.e. inhouse on a mag bench). There is a specific requirement that type A UV-A LED lights should have a minimum beam profile of 5 inches with intensity greater or equal to 1,000 µW/cm2. Labino’s GX Orion, BB 2.0 Series AC (Mains) and MB 3.0 Series AC (Mains) models fall into Type A category.
(b) Type B – These are lights powered by a battery and correspond primarily to portable and stationery applications. There is a specific requirement that type B UV-A LED lights should have a minimum beam profile of 5 inches with intensity greater or equal to 1,000 µW/cm2. Labino’s BB 2.0 Series battery and MB 3.0 Series battery powered models fall into Type B category.
(c) Type C – These are lights powered by a battery and correspond primarily to single LED flashlights. There is a specific requirement that type C UV-A LED lights should have a minimum beam profile of 3 inches with intensity greater or equal to 1,000 µW/cm2. Labino’s UVG3 2.0 Series and UVG5 2.0 Series models fall into Type C category.
The tests previously listed are required for all three types. Types B and C are also required to illustrate the typical battery discharge time and discharge plot.
The ASTM E3022-18 standard provides detailed instructions on how to perform measurements for every test. It also provides uniformity and clarity on how to report the findings so that users reading the report can make an educated decision how to use the lights, at what working distance, what is the covered area but also to have like to like information and compare one model with another (not necessarily of the same manufacturer). For example, you can compare graphically the beam irradiance profile (Section 7.4 and Fig. 1) between two models. The standard specifies:
(a) the range of intensities to be used, and
(b) the colors to be used illustrating each range, as follows:
Blue: < 200 μW/cm2
Green: 200 – 1000 μW/cm2
Yellow: 1000 – 5000 μW/cm2
Red: 5000 – 10000 μW/cm2
White: > 10000 μW/cm2
To perform non-destructive testing using a UV LED light you need to use a light that makes the chemicals fluoresce. NDT chemicals for MPI and FPI only fluoresce under a certain wavelength. Most standards, including ASTM E3022-18 specify the wavelength to be between 360-370 nm. The UV light must irradiate a minimum intensity at a predefined working distance. The more the wavelength moves away from this range, the probability to see an indication diminishes.
The tests performed essentially make sure that the light is stable and there are no variations observed in beam intensity, flickering or strobing. Not just when a light is powered on, but also when it is warm. Why is this important?
(a) Intensity is not fixed; it changes due to heat. If the light generates more heat than it should, intensity can drop significantly, much below the initial intensity, without the NDT operator even noticing. Risk: The more the intensity drops, the working distance and the covered area, both decrease much more than the NDT inspector is used to (or told to expect) and there is a greater risk of missing the indication.
(b) Wavelength is not permanent; it changes due to heat. If the light generates more heat than it should, the wavelength can shift above the allowable limit of 370nm without the NDT operator even knowing. Risk: The more the wavelength moves away from 370nm, the greater the risk of missing a crack.
“…tests are performed as a single unit to determine the effectiveness of the cooling system on the LEDs and keep the intensity and wavelength within check.“
The key reason why the ASTM E3022-18 standard specifically asks the tests to be performed 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, is exactly that. To be able to determine the effectiveness of the cooling system on the LEDs and keep the intensity and wavelength within check.
All parts listed above and in Section 1.2 of the ASTM E3022-18 standard affect heat one way or another; how heat is generated, how heat circulates inside the unit and how heat is extracted outside the light. Regardless whether the unit is fan cooled or wether it has a mechanical cooling system, the intensity must not drop more than 20% and the wavelength must not exceed 370nm. For this reason, it is not possible for any component to be tested individually as no measurements relating to ASTM E3022-18 standard can be derived from such exercise.
“…it is not possible for any component to be tested individually as no measurements relating to ASTM E3022-18 standard can be derived from such exercise.“
LED replacement bulbs that are marketed as ASTM E3022-18 compliant for use by lights that used to carry mercury bulbs are deceiving. They have nothing to do with the ASTM E3022-18 standard. An ASTM E3022-18 certification cannot be performed without testing ALL the parts that make the light, as one unit. We have a list of several Chinese and Indian manufacturers with American and European distributors that sell such bulbs and are falsely claiming compliance. If you have been offered such products, I strongly suggest you report these to your local ASNT or other NDT related chapter.
“LED replacement bulbs that are marketed as ASTM E3022-18 compliant for use by lights that used to carry mercury bulbs are deceiving. They have nothing to do with the ASTM E3022-18 standard.“
Furthermore, LED replacement bulbs for self-maintenance on existing LED lights are not allowed by ASTM E3022-18. The manufacturer needs to re-certify a light that had a critical part to the optical output of the light replaced.
There is always a reason when an LED fails. Most of the times is due to one of the following: the wrong current was used, an inefficient driver was implemented, the cooling system does not correspond to the requirements of the overall system etc. LEDs are not meant to last a few months as low-cost manufacturers that sell freely replacement parts claim. If your stationery light needs frequent replacement of LEDs, you cannot trust it to emit the correct wavelength either. It means it overheats much above what the light can take and prompts intensity and wavelength to move in the wrong direction. Intensity moves lower and wavelength moves higher.
The ASTM E3022-18 standard makes sure that these mistakes are kept in check. As ASTM E3022-18 tests and measurements are made by the manufacturers for their own products, it is prudent to choose a manufacturer with credibility.
“…LEDs are not meant to last a few months as low-cost manufacturers that sell freely replacement parts claim. If your stationery light needs frequent replacement of LEDs you cannot trust it to give you the correct wavelength either. It means it overheats much above what the light can take and causes variations in intensity and wavelength.“
Labino’s GX Orion stationery light carries a 3-year warranty and has not had a single LED out three years after its launch in any of the 50 countries it was sold. Several other manufacturers have quality products as well. There is a large difference in quality and adaptation of standards such as ASTM E3022-18 between serious manufacturers and low-cost manufacturers who like to take shortcuts.
Labino AB as well as several other manufacturers keep their reference lights locked and safe. Any end user that has bought a Labino UV light is welcome to come and verify with us that the properties we publish in our Type test reports match the actual Labino reference model.
The ASTM E3022-18 standard also requires the manufacturer to specify the extreme temperatures that a light can withstand. That is why specialized equipment is required, such as a climate chamber, to regulate and test at different temperatures. Labino UV models, for example, are routinely checked to endure in 122˚ Fahrenheit (50˚ Celsius).
The standard also requires measurements of the filters used to minimize visible light and UV-B and UV-C emission, all variables that can be the cause of a distraction during an inspection and / or cause damage to the human eye. A filter must have the following transmittance qualities at each wavelength: 380 nm ≤ 85%, 400 nm ≤ 30%, 420 nm ≤ 5%, 425 to 670 nm ≤ 0.2%.
Ambient light during tests performed, including when you perform your daily irradiance measurements, must be less than 2 fc (21.5 lux). Temperature during tests must also be stable at 77 ± 5°F (25 ± 3°C).