Equinox Systems CARINA User Manual page 15

Equinox Carina Laser Safety
Hazard Distances
All lasers for display porposes feature a characteristic called the hazard distance for direct
viewing (NOHD). The (NOHD) is distance at which viewing the laser directly is no longer
considered a hazard. Note at any point between the laser unit and the calculated hazard distance,
it may be hazardous to directly view the laser beams. Exposing the eye to the laser directly from
outside the hazard distance is considered to be no longer a risk.
The most dangerous senerio is to look directly at a static single beam, because all the light energy
is concentrated into one small point. The hazard distances for various different powers of Class 3B
laser are shown in the table below.
10mW 30mW 50mW 100mW 250mW 450mW
Laser Output Power
Hazard Distance
12m 20m 25m 36m 56m 76m
Note - The above values in the table have been calculated assuming the characteristics of a
typical laser, which has a beam spread of 2mradians. Not all laser units have the same
specification.
Remember: Static laser beams are hazardous for long distances so it is recommended that the
laser beams are projected overhead and not into the viewing audience
Laser Safety Books
The Radiation Safety of Display Laser Installations HS(G)95
Published by HSE Books 1996 ISBN 0 7176 0691
Health & Safety Executive
Website - www.hse.gov.uk
Laser display safety guidance page - www.hse.gov.uk/pubns/INDG224.htm
Health Protection Agency
Website - www.hpa.org.uk