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SEN LIGHTS Corporation is a specialized company of manufacture and Sale

TEL. +816-6845-5111

1-5-23 Hashirii Toyonaka Osaka 561-0891 JAPAN

TechnologyTECHNOLOGY

Safety Management of Ultraviolet Radiation


Table 1. Permitted Tolerant Exposure
wavelength
(nm)
TLV
(mJ/cm2)
relative
hazardous
ratio
200
220
230
250
254
260
270
290
300
305
315
100
25
16
7.5
6.0
4.6
3.0
4.7
10
50
1000
0.03
0.12
0.19
0.43
0.5
0.65
1.0
0.64
0.30
0.06
0.003

INTRODUCTION

  Ultraviolet radiation is harmful to the human body, particularly causing disturbance in the functions of eye & skin.

The degree of irradiation risks varies depending on the wavelength of radiation, and its details have been clarified today.

 As human eyes are most susceptible to ultraviolet radiations, we consider eyes as the most important organ for us to protect from exposure.


PERMITTED TOLERANT UV EXPOSURE

 Table-1 shows a permitted tolerant value of UV exposure for each wavelength, which we call TLV (Threshold Limit Value) in accordance with the recommendation given by the ACGIH (the American Conference of Governmental Indutial Hygienists).

 The most harmful wavelength is 270nm and its value of TLV is the lowest 3mJ/cm2.
The figure 1 shows harmful ratio having relevance to the spectrum.

LOW PRESSURE MERCURY LAMP

 The main wavelengths of LP Hg lamp are 254nm & 185nm. The summed energy of both UV ray occupies 90% of the total radiation.The single 254nm radiation occupies 80% of the total energy. The wavelength of 254nm is so hazardous as well as a high energy ratio, you have to concentrate your protection measures only on the 254nm when you handle a low-pressure mercury lamp.


HIGH PRESSURE MERCURY LAMP

 High pressure mercury lamps irradiate wider range of line spectrum and continuous wavelength, from UV to infrared. The main wavelength is 365nm. Unlike low pressure mercury lamps the high pressure mercury lamps have a lower 254nm ratio. In case of SEN Lights HL-100 lamp, only 8% of whole emission energy is from 253.7 to 276nm ray, but the danger is about 170 times of 315nm, for safety measures, it is rational to use 254nm as the standard rather than 365nm. High pressure mercury lamp irradiate many wavelength, hence to calculate the tolerated value, exposure value of each wavelength must be integrated. Practically, from dangerous point of view, overall exposure is about twice as that of 254nm, therefore half of tolerated value makes thing safety.





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SEN LIGHTS Corporation


1-5-23 Hashirii Toyonaka Osaka 561-0891 JAPAN

TEL +816-6845-5111
FAX +816-6857-3468