Light Meter Accuracy Specifications : Should They be Reassessed

摘要

Historically, Visible light measurements were required to assure adequate contrast between indication and background. The technologies in use at the time specifications were issued utilized Mercury Vapor lighting equipment with a very narrow band of UV-A output around 365nm. Meters available in the NDT market are sensitive to visible light from 400nm-760nm, but also interpret the UV-A region of 380-400nm as visible (White light). To maximize the probability of detection in NDT inspections, it is necessary to increase the inspector's chances of "seeing" an indication, which may have formed. MPXL technology allows inspections to be performed in daylight with the same levels of visual acuity as an inspection in a darkened area using less intense Mercury Vapor lighting. Our industry needs to evaluate the regulations pertaining to visible light and acknowledge that MPXL technology is a powerful tool necessary to assure the highest degree of confidence in the NDT test results.