The highest power or energy density (in W/cm2 or J/cm2) of a light source that has a negligible risk for causing damage to an exposed surface of the body. It is measured at the cornea or skin for a given wavelength and exposure time...
An interlock where the failure of a single mechanical or electrical component of the interlock will cause the system to go into, or remain in, a safe mode...
The product of power (watts) and duration (seconds). One watt second = one Joule.