Protecting Workers from Ultraviolet Radiation - icnirp

Protecting Workers from Ultraviolet Radiation
In recent years, the largest use of UVC lamps has been to disinfect sewage effluents, drinking
water, water for the cosmetics industry and swimming pools. The combination of UV radiation
and ozone has a very powerful oxidizing action and is capable of reducing the organic content of
water to extremely low levels. Germicidal lamps are sometimes used inside microbiological
safety cabinets to inactivate airborne and surface micro-organisms as well as in vacated
operating theatres overnight. UVC lamps have been used since the 1930s to decrease the levels
of airborne bacteria in operating theatres during surgery, but the technique is not widely used,
because of the necessity to protect the eyes and skin of personnel and patient; filtered air units
with UVC lamps are currently preferred. Workers maintaining UVC lamp systems require
proper training to avoid accidental exposure, and clear face shields with protective clothing are
required if work during UVC emission is possible.
5.3.3 Photocuring and hardening
Many industrial processes, such as the curing of lacquers, inks, glues and sealants, employ UV
photochemical hardening (“drying”), and this is termed UV photocuring. Hardening of glues and
plastics is often performed with UVA sources, where the exposure is relatively low. However,
for special applications, sources that also emit UVB and UVC radiation are used. These
processes often necessitate the use of high-power (several kilowatts) lamps, such as highpressure
metal-halide lamps. Whilst these high power lamps can emit very high levels of UVR,
the industrial process is generally housed in interlocked assemblies and behind opaque baffles to
prevent hazardous exposure to personnel under normal use. Maintenance procedures must be
designed to assure resetting of interlocks prior to restarting the equipment after lamp exchange
and servicing.
Traditionally, UVA has been used extensively in photocuring of dental resins in reconstruction
of teeth. However, this has been recently replaced by visible blue light sources.
5.3.4 Banking and commerce
Signature verification is commonly performed by exposing a signature, obtained previously with
colorless ink, to UVA radiation under which it fluoresces. Also, fluorescent features of banknotes
can be checked with UVA lamps, and recently with UV LEDs, and these methods are often used by
cashiers in stores. The electrical power of the lamps is normally no more than a few Watts and
exposure time is short. Also often the lamps are shielded from direct line of sight. In normal use, no
occupational UVR hazard to the eye or the skin results.
5.3.5 Entertainment facilities
UVA “blacklight” lamps are frequently used in discotheques, theatres, bars and other entertainment
facilities to induce visible fluorescence in clothing, posters, and other fluorescent materials. Whilst
the UVA levels are normally well below 10 W m -2 and would not normally present eye or skin
hazards from the occasional direct exposure, UVC lamps installed inadvertently have led to severe
photokeratitis.
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