6
Dymax EC-Series Flood Lamps for UVCS Conveyors User Guide
3 mW/cm
2
of UVA light and also include the more dangerous UVB light (primarily responsible for sun tans, sun
burns, and skin cancer) as well.
Checking the Workstation
The human eye cannot detect "pure" UV light, only visible light. A radiometer should be used to measure stray
UV light to confirm the safety of a UV light-curing process. A workstation that exposes an operator to more
than 1 mW/cm
2
of UVA continuously should be redesigned.
Protecting Operators
Light-curing technology can be a regulatory compliant, "worker-friendly" manufacturing process when the
proper safety equipment and operator training is utilized. There are two ways to protect operators from UV
exposure: shield the operator and/or shield the source.
Shield the Operator
—
UV-Blocking Eye Protection - UV-blocking eye protection is recommended when
operating UV light-curing systems. Both clear and tinted UV-blocking eye protection is available from Dymax.
UV-Blocking Skin Protection
—
Where the potential exists for UV exposure upon skin, opaque, UV-blocking
clothing, gloves, and full-face shields are recommended.
Shield the Source of UV
Any substrate that blocks UV light can be used as a shield to protect workers from stray UV light. The following
materials can be used to create simple shielding structures:
Rigid Plastic Film
—
Transparent or translucent/UV-blocking plastics (typically polycarbonate or acrylic) are
commonly used to create shielding where some level of transparency is also desired.
Flexible Film
—
Translucent UV-blocking, flexible urethane films can be used to quickly create workstation
shielding. This UV-blocking, flexible urethane film is available from Dymax, call for assistance.
Ozone
Standard Dymax bulbs (UVA type) generate an insignificant amount of UVC and therefore essentially no
ozone. Some UV light-
curing systems, like those used to cure UV inks, emit primarily “shortwave” (UVB and
UVC) energy. Upon exposure to UVC light (specifically <240 nm), oxygen molecules (O
2
) split into oxygen
atoms (O) and recombine with O
2
to create ozone O
3
. The current, long-term ozone concentration limit
recommended by ACGIH, NIOSH, and OSHA is 0.1 ppm (0.2mg/m
3
).
High-Temperature Surfaces
Surfaces exposed to high-intensity curing lights will rise in temperature. The intensity, distance, exposure
time, cooling fans, and the type/color of the surface can all affect the actual surface temperature. In some
cases, exposed surfaces can reach temperatures capable of producing a burn or causing damage to a
substrate. In these cases, care must be taken to ensure either a more moderate surface temperature or
appropriate protection/training for operators.
