No, they are not the same
The key question is what is the accuracy, repeatability and reliability of the UV light meter?
Accuracy and Calibration
- (1). NIST:
The National Institute of Standards and Technology is the world wide accepted standard for accuracy and repeatability.
Using the NIST standard insures the measurements are accurate and repeatable over long term usage.
Many UV light meters manufactured in the US use this standard. However, many UV meters manufactured in Asia or Europe use in-house measurements. The measurement recorded is based upon the electronic and glass probe design by that manufacturer. This is found typically in low-end priced light meters.
- (2). Linearity:
Is the mw/cm2 or mj/cm2 measurements linear across the light meter’s specified range?
High pressure mercury lamps degrade over time changing lamp output which lowers the mw/cm2 and mj/cm2 measurements.
If the UV meter is not linear over the full range of the meter, then the mw/cm2 measurement maybe erroneous creating exposure problems.
- (3). Degradation:
The electronic components and glass filters can change over time unless high quality components are not used when assembled.
Careful consideration must be given, by the manufacturer, when selecting electronics components and glass filters when designing and manufacturing UV meters.
A wide range of electronic components and glass filters are available. Some of these components and filters degrade over time and care must be taken in selecting the quality of those electronic components and glass filters. They are more costly but do not degrade which is reflected in the UV meter’s price.
- (4). Reliability
G&R Labs UV light meters are designed and manufactured for decades of use starting with the aluminum housings. The majority of UV light meters manufactured by G&R Labs since 1994 are still operational when used through “the normal course of business” and yearly calibrations.
- (5). Re-Calibrating)
UV meter need to be calibrated, typically once a year. Getting a UV meter calibrated, should be, a major factor in the decision process when buying a UV meter.
Through usage, UV meters get damaged. The wires in the cabling become broken. The probe’s glass filters becomes broken or dirty. Electronic components, such as in calibration set pots, can change over usage. Glass filter can degrade over time.
Calibration of UV meters can occur in one of two places either in the basic unit itself or in the probe head attached to the basic unit. Regardless where the actual calibration corrections occur, there are key questions to consider.
- (1). Is a calibration certificate included with the new UV meter? Answer: Maybe, depends upon the manufacturer.
- (2). Are all calibrations the same? Answer: No! Many low-end UV meters use in house guidelines. NIST is the only accept standard world wide.
- (3). Will I measure the same mw/cm2 after calibration? Answer: This depends upon whether NIST was the original calibration standard.
- (4). Where do I send the UV meter for calibration? Answer: Depends if you want consist measurement standards long term.
- (5). What is the turn around time to have a new calibration done? Answer: Depends on who does the new calibration.
- (6). How much does it cost for a new calibration? Answer: Compare the cost of a new UV meter that can be re-calibrated long term to low-end units that cost slight more than the price for re-calibration short term.
For those UV application requiring accurate and repeatable measurements:
G&R Labs’ UV light meters are designed and manufactured for those applications requiring accuracy, repeatability, interchangeable probes measuring different wavelengths, and are all traceable to NIST standards within +/-3% published specification. We have an in house +/-0.5% Radiometric standard and a +/- 0.5% Photo-metric standard and all tied to a known NIST wavelength standards. It takes extra work in design, making sure we have stringent quality control, our calibrations are based on NIST standards, and we know the value of accuracy in meeting your application needs.
Also, all of our UV light meters are issued with a calibration certificate whether it is a new meter or a re-calibrated meter with a one day turnaround time.
Thank you for contacting us and we look forward to meeting your application needs.