Document b5morev9MK7Q4x87BjRjEBgKg

Personal Protective Equipment TABLE 38--A TRANSMITTANCES AND TOLERANCES IN TRANSMITTANCE OF VARIOUS SHADES OF FILTER LENSES Shade No Optical Density Mtn Std Max Luminous Transmittance Max Std Mtn Maximum Infrared Transmit- fence Maximum Spectral Transmittance in the Ultraviolet and Violet for Four Wavelengths (millimicrons) 313 334 365 405 1 5 017 1 7 0 26 20 0 36 25 054 30 0 75 0 214 0 300 0 429 0643 0 857 026 0 36 054 0 75 1 07 per cent per cent per cent 67 55 43 29 180 61 1 501 37 3 228 13 9 55 43 29 18 0 850 per cent 25 20 15 12 90 per cent per cent per cent per cent 02 08 25 65 02 07 20 50 02 05 14 35 02 03 5 15 02 02 05 6 40 1 07 1 286 1 50 8 50 518 316 50 02 02 05 10 50 1 50 1 714 1 93 3 16 1 93 1 18 25 02 02 02 05 60 1 93 2143 2 36 1 18 0 72 044 1 5 01 01 01 05 70 236 2 571 2 79 044 0 27 0164 13 01 01 01 05 80 279 3 000 3 21 0 164 0100 0 061 1o 01 01 01 05 90 100 110 120 130 140 3 21 364 4 07 4 50 493 5 36 3 429 3 857 4 286 4 714 5143 5 571 364 4 07 450 4 93 536 5 79 0 061 0 023 0 0085 0 0032 0 0012 0 0004 0 037 0 0139 0 0052 0 0019 0 00072 0 00027 0 023 0 0085 0 0032 00012 0 00044 000016 08 06 05 05 04 03 01 01 0 05 005 0 05 0 05 01 01 0 05 0 05 0 05 0 05 01 01 0 05 0 05 0 05 0 05 05 05 01 01 01 01 NOTE The values given apply to class I filter glass For class II filter lenses, the transmittances and tolerances are the same with the additional requirement that the transmittance of 589 3 millimicrons shall not exceed 15 per cent of the luminous transmittance Some of the headings in this table have been changed to conform with NBS Letter Circular LC857 Spectral-Transmissive Properties and Use of Eye-Protective Classes Reprinted from National Bureau of Standards Circular 471,1948 ____________ 1162 DICHROIC coated glass plate (coating faces eyes, and therefore require special attention Ultraviolet rays can produce cumulative destructive changes m the structure of the cornea and lens of the eye Short exposures of intense ultraviolet radiation or prolonged exposures to ultraviolet radiations of low intensity will produce painful, but ordinarily self-repairing corneal damage Radiations m the visible light band, if too intense, can cause eyestrain and headache, and can destroy the tissue of the retina Infrared radiations transmit large amounts of heat energy to the eye, causing discomfort The damage produced is superficial The filtering properties of filter lenses have been established by the National Bureau of Standards The percentage transmittance of radiant energies m the three bands--ultra- 4 Fig 38-18 --Diagram shows how "antilaser eyeshield" deflects laser beam