Appendix 2 25
r) Radiant Exposure – A means of expressing the intensity of the beam. This is generally expressed as J/cm ².
s) R eflections– reflections can be either diffuse or specular.
1. D iffuse Reflection - The component of a reflection from a surface commonly found with f lat finish paints or rough surfaces. A diffuse surface will reflect the laser beam in many directions.
2. Specular Reflection – A mirror-like reflection that usually maintains the directional ch aracteristics of the beam.
t) S afety Observer - A designated person who is responsible for monitoring the safe operation of a laser and who can immediately terminate the laser beam if necessary to ensure safety. Normally, a s afety observer will view airspace in the vicinity of a laser beam to identify any potentially unsafe condition.
u) Sl ant Range – The distance directly along the beam
(e.g.
, “slant range” does not vary depending on beam elevation angle).
v) T erminated Beam - A laser beam that is blocked from entering navigable airspace.
w ) Unterminated Beam - A laser beam that is directed or reflected into navigable airspace. The proponent should provide sufficient evidence to the FDA and the FAA that users of the NAS are not affected.
x) Va riance - Permission from FDA for a laser manufacturer and/or operator to deviate from one or more requirements of 21 CFR 1040 when alternate st eps are taken to provide equivalent level of safety.
y ) Watts - A u nit of measurement associated with power output. Often the wattage of a laser system is prefixed with milli (mW), micro (µW) and nano (nW). One watt is one joule per second.