Class 3B lasers are hazardous for eye exposure. They can heat skin and materials but are not considered a burn hazard. For visible-light lasers, Class 3B lasers' output power is between 5 and 499 milliwatts.
Class 3B is the same as the Roman numeral "Class IIIb" you may see on some lasers' labels. At this website, we primarily use the Arabic numerals, for convenience.
SAFE USE GUIDANCE - GENERAL
Class 3B visible-beam lasers are medium powered, from 5 to 499 milliwatts. A Class 3B laser can cause eye injury. The more powerful the laser, the greater the chance of injury.
Use of laser protective eyewear is suggested or recommended (depending on the laser's power level), as discussed elsewhere on this page.
A Class 3B laser can be a distraction, glare or flashblindness hazard for pilots and drivers. NEVER aim any laser towards an aircraft or vehicle that is in motion. This is unsafe and is illegal -- you could be arrested and jailed.
Always be aware of the beam location. Keep it away from people's eyes and heads. Watch out for reflected beams from glass and shiny surfaces. When outdoors, you must avoid aiming at or near aircraft.
ONLY ALLOW USE BY RESPONSIBLE PERSONS This is not a toy. Children should not be permitted to use Class 3B lasers. Any teenager using a Class 3B laser should be continuously supervised by a responsible adult. A number of teenagers have caused eye injuries to themselves or others by misusing Class 3B and Class 4 lasers.
DO NOT USE AS A LASER POINTER Class 3B (and 4) lasers are too powerful to be used as pointers. Some Class 3B (and 4) lasers may look like pointers, but these should not be used for pointing. Use a Class 2 (less than 1 mW) or Class 3R (less than 5 mW) laser for pointing purposes.
CLASS 3B LASER HAZARDS
SAFETY NOTICE: This website is intended for the educational, instructional and informational purposes of the user and is not to be considered a substitute for a knowledgeable and trained Laser Safety Officer (LSO) with the duties and responsibilities as defined in the ANSI Z136 standard published by the American National Standard Institute.
The hazard distances listed below are intended only as general guidance. This is because 1) your laser may vary from the parameters (power, divergence) listed below, and 2) information on labels or marketing materials may not always be correct. For example, studies have shown that some laser pointers may be falsely labeled to avoid regulations -- the actual power may be 10 times or more what the label indicates.
Always err on the side of safety. If your laser has not been measured by a knowledgeable and trained Laser Safety Officer, assume it is more hazardous than the label or marketing materials would indicate.
EYE INJURY HAZARDS
EYE INJURY HAZARD -- DIRECT AND REFLECTED BEAM Class 3B visible-light lasers are hazardous for eye exposure. They can cause burns to the retina. A person cannot turn away or blink fast enough to prevent retinal eye injury from a nearby Class 3B laser.
At the low end, around 5 to 50 milliwatts, a Class 3B laser poses a moderate risk of eye injury. It is unlikely that a handheld beam aimed from more than a few dozen feet away would cause injury -- laser light could not stay on one spot on the retina long enough for heat to build up to injurious levels. However, the risk is increased if the beam is held steady or if the laser is relatively close to the eye.
As the laser power increases, the risk of eye injury also increases. At the high end, around 250 to 500 milliwatts, even a brief exposure could cause retinal damage.
Avoid all eye exposure to beams from Class 3B lasers. This includes unintentional or accidental exposures -- be careful to keep the beam away from eyes and faces.
Also, remember that reflections off mirrors, glass, and shiny surfaces can be just as hazardous as the direct beam. Avoid reflected Class 3B beams the same way you would avoid the direct beam.
The Nominal Ocular Hazard Distance (NOHD) for a lower-powered 50 mW Class 3B visible-beam laser with a tight beam (0.5 milliradian divergence) is 330 ft (100 m).
The Nominal Ocular Hazard Distance (NOHD) for the most powerful 499 mW Class 3B visible-beam laser with a tight beam is 1,050 ft (320 m).
Additional types of Class 3B lasers are listed in the Laser hazard distance chart.
If you are closer than the NOHD distance to the laser, there is a possibility of retinal damage if the direct or reflected beam enters your eye. The closer you are to the laser and the longer the beam is in the eye, the greater the chance of injury.
Color indicates the relative hazard: Red = potential injury, green = unlikely injury. Beyond the Nominal Ocular Hazard Distance, the chance of injury is “vanishingly small” according to safety experts.
POTENTIAL EYE INJURY HAZARD - DIFFUSE REFLECTION The scattered light from the laser "dot" as viewed on a surface, normally is not an eye hazard. However, it is possible for a higher-powered Class 3B laser's "dot" to be a diffuse reflection hazard. Therefore, avoid staring at the laser dot at close range, for more than a few seconds. The light is too bright if you see a sustained afterimage, lasting more than about 10 seconds.
Looking at the laser dot from the most powerful Class 3B laser, 499 milliwatts, for more than 10 minutes is an eye hazard within 5 in (12 cm) of the laser.
If you are within this close range for this length of time, use protective eyewear.
SKIN INJURY (PAIN)
A Class 3B laser is not normally considered a skin or materials burn hazard. However, if the laser "dot" is kept motionless on skin at close range, heat can be felt. The more powerful the Class 3B laser, the sooner the heat will build up.
Do not deliberately attempt to burn skin. This can be very painful, can take long to heal, and can leave a permanent scar.
If the laser "dot" is kept motionless on a material for a few seconds at close range, higher-powered Class 3B lasers can cause materials to smolder or burn. Dark materials which absorb heat, and lightweight materials such as paper and fabric, are most easily burned by visible laser beams.
AIRCRAFT AND VEHICLE SAFETY
LASERS CAN INTERFERE WITH PILOTS, DRIVERS NEVER aim any laser towards an aircraft or vehicle that is in motion. The bright light can flashblind, cause glare, or distract the pilot or driver. This is why aiming any laser towards an aircraft is illegal.
The most powerful Class 3B laser beam (499 mW) can temporarily flashblind a pilot or driver, causing afterimages, within 1 mile (1.6 km) of the laser.
It can cause glare, blocking a pilot or driver's vision, within 4.4 miles (7.1 km) of the laser.
It can cause distraction, being brighter than surrounding lights, within 44 miles (71 km) of the laser.
The above calculations are for a 555 nanometer green laser with a tight beam (0.5 milliradian divergence). These parameters are very conservative and thus result in the longest visual interference distances for a Class 3B consumer laser.
The more the beam spreads out, the shorter the hazard distances. For example, for a 499 mW 555 nm green laser pointer with a beam spread of 1 milliradian, divide the above numbers by 2 to find the visual interference distances.
Green is the most visible color to the human eye. It will appear brighter and more distracting than other colors of equal power. For red, divide the above numbers by about 5 to get an approximation of the visual interference distances. For blue, divide the above numbers by about 20.
Visual interference distances for other Class 3B lasers are listed in the Laser hazard distance chart.
Never aim a laser at or near aircraft or vehicles, no matter what its color or power.
LASING AIRCRAFT AND VEHICLES IS ILLEGAL In the U.S., aiming a laser at or near the flight path of an aircraft is a federal felony, punishable by up to 5 years in jail and a fine of up to $250,000. Other countries, and U.S. states have similar laws for interfering with safety; such laws may be used to arrest, fine or imprison a person for aiming at aircraft and vehicles.
The power of the laser does not matter. Even if a laser's power is relatively weak, aiming ANY laser beam at an aircraft or vehicle is illegal.
Persons aiming higher-powered beams are especially likely to be caught, because the beam is very visible from the air. It is easy for police helicopters to trace the beam back to the perpetrator's location.
See this page for a selected list of the many persons who have been jailed and/or fined for aiming lasers at aircraft.
CLASS 3B SAFE USE GUIDANCE - LASER PROTECTIVE EYEWEAR (GLASSES)
Laser glasses or goggles are suggested for lower-powered Class 3B lasers, and are recommended for higher-powered Class 3Bs. They should be selected to protect against the laser's power and wavelength.
The eyewear should not block out all of the laser's light. This is because it is necessary to see where the laser "dot" is, to safely work with the laser. Because the eyewear is blocking some or perhaps all of the laser's light (for example, a hazardous reflection) you still should use caution even when using laser protective eyewear.
As you use the laser, any other persons in the area should also have the same type of laser protective eyewear as you.
DO NOT USE SUNGLASSES FOR LASER PROTECTION Sunglasses are NOT laser protective eyewear. They are not rated (e.g., with Optical Density) to ensure light-attenuating protection. Most sunglasses will not block enough laser light to significantly reduce hazardous exposures.
CLASS 3B SAFE USE GUIDANCE - FOCUSING THE BEAM
Some lasers may have built-in lenses or screw-on accessories, in order to make the laser "dot" sharper or fuzzier.
Any device that can focus the dot to be sharper, or the beam to be tighter than its normal width, will increase the hazard range and the risk of injury. Use extra caution when the beam is focused.
CLASS 3B SAFE USE GUIDANCE - LASER PROJECTORS
If this laser product is a projector for displays or laser shows, please be aware of the following:
NOT INTENDED FOR AUDIENCE SCANNING Scanning the laser beam, by moving it quickly in various patterns such as lines or circles, does NOT significantly reduce hazards.
Do not aim this laser projector directly at any person or audience area. Deliberate scanning onto an audience with a Class 3B or 4 laser is inherently hazardous.
Because the labels on consumer lasers may give incorrect information -- the wrong Class or the wrong power -- do NOT rely on the label for any safety-critical calculations. Any laser aimed into an audience-accessible area must be measured with appropriate equipment by a qualified Laser Safety Officer. The LSO will determine the laser's Nominal Ocular Hazard Distance. The audience must be further than this distance. The LSO will also determine any other safety measures to be taken; for example, continuous supervision of the area, emergency stop buttons, etc.
In addition, in the U.S. and many countries and venues, special permission is required before ANY human access to Class 3B or 4 laser beams is allowed -- even if the audience is further than the NOHD. For example, the U.S. Food and Drug Administration (FDA) requires submission and FDA approval of an audience scanning variance, before any public performance can take place.
U.S. LASER DISPLAY REGULATORY INFORMATION Lasers used for demonstrations, shows, displays and entertainment are highly regulated in the U.S. Both the laser projection device and the way in which it is used (the laser show) must be certified to the Food and Drug Administration. This is for ANY laser show even if the laser beam is kept away from audience areas. Generally, shows in a private home with friends and family are not covered but all other demonstrations, shows, displays, etc. done with a Class 3B or 4 laser would require the user to submit a variance, and get FDA approval in advance before the show can proceed.
Do not perform any public demonstration, show, display or entertainment with this laser projector, without having a variance from FDA. More information is available from FDA or the International Laser Display Association.
In addition to federal laws, some states and jurisdictions also regulate laser equipment and/or usage. Contact information for state agencies is available from Rockwell Laser Industries.
U.K. LASER DISPLAY REGULATORY INFORMATION At the national level, laser show safety advice is given by Public Health England, formerly the Health Protection Agency. On their website they give the following guidance (as of 27 March 2014):
The NRPB, now the Radiation Protection Division of the Health Protection Agency, has undertaken considerable research into the use of lasers in the entertainment industry. Some situations have given cause for concern, mainly because the potential or actual exposure of people, including the audience, has not been properly assessed. The use of lasers may be covered by conditions on the premises under the Licensing Act, which is enforced by the local council (district, unitary or other authority). HPA advice to such councils is that a risk assessment should be carried out to demonstrate that people are not exposed to unacceptable risks. Assessment of laser display effects used for intentionally scanning the audience is time-consuming and complex. HPA experience is that such assessments are rarely satisfactorily undertaken and the practice should not routinely take place.
COUNTRIES OTHER THAN THE U.S. AND U.K. Many other countries and jurisdictions have regulations regarding laser show and display usage. Venues such as concert halls may have their own requirements.
Contact all appropriate authorities to ensure your laser show meets venue and government requirements.