Читать книгу Patty's Industrial Hygiene, Physical and Biological Agents - Группа авторов - Страница 136
5.3.3 Filter Shade Numbers
ОглавлениеThe ANSI Z87.1‐2015 standard for eye and face protection established transmittance requirements for general‐purpose filter lenses, which are identified by shade numbers (58). Shade number is determined by the manufacturer of the lens using the following formula:
(29)
where TL is the luminous transmittance (the nominal fraction of photopic‐weighted visible light that is transmitted through the filter). A maximum effective transmittance in the “far‐UV” region (200–315 nm) and a maximum IR average transmittance (780–2000 nm) are specified by the standard for each shade number. The transmittance of blue‐light‐weighted radiation for a shade must be less than the luminous transmittance for that shade.
FIGURE 10 Firefighters on a field training exercise wear aluminized clothing for protection against radiant heat.
Source: Photo by Airman 1st Class Kathrine McDowell, U.S. Air Force.
