Laser Safety
Laser safety information for BT Laser Studio and OSC-1's laser DAC output — classifications, best practices, and FDA compliance.
Laser safety is non-negotiable for any public laser display. This page covers the basics — always consult a Laser Safety Officer for show-specific compliance.
Lasers in the Class IIIb and Class IV categories can cause immediate and permanent eye and skin injury. Never point laser beams at people, animals, or aircraft. Every public display in the United States requires strict FDA compliance. Consult a certified Laser Safety Officer.
Laser Classifications
| Class | Power Range | Risk Level |
|---|---|---|
| II | < 1mW visible | Low (blink reflex protects) |
| IIIa / 3R | 1–5mW | Moderate (direct viewing hazardous) |
| IIIb / 3B | 5–500mW | High (immediate eye hazard) |
| IV / 4 | > 500mW | Extreme (fire risk, immediate hazard) |
Most laser show projectors are Class IIIb or Class IV. They operate in a safe manner only when properly positioned, controlled, and operated by trained personnel.
FDA vs IEC class names. The table above uses the legacy US FDA/CDRH names. Newer hardware is often labeled under the international IEC 60825-1 scheme, where Class IIIa ≈ 3R, Class IIIb ≈ 3B, and Class IV ≈ 4. Under FDA Laser Notice 56, products conforming to the comparable IEC clauses are accepted in the US.
US FDA Regulations
In the United States, public laser light shows require FDA Center for Devices and Radiological Health (CDRH) compliance under Title 21 CFR Part 1040.11.
Key requirements:
- Audience scanning — directing laser radiation above Class I limits into the audience is prohibited unless you hold a special audience-scanning variance and use a projector certified for it
- Separation zone (the 3.0 m / 2.5 m rule) — under the conditions of FDA Form 3147, beam radiation above the Class I limit must stay at least 3.0 m (9 ft 10 in) vertically above any surface an audience member can stand on, and at least 2.5 m (8 ft 2 in) laterally (and below) from any place the audience can reach
- Variance — the show operator must apply for and receive an FDA variance (Form 3147) before any public Class IIIb/IV show. Note: an accession number printed on a projector only means the FDA received the manufacturer's report — it is not an approval or a safety certification
- Annual report — variance holders must file an annual report (Form 3636) by September 1 each year, or the variance can be canceled
- Emergency stop — a shutter or kill switch must be immediately accessible, and any scanning effect must use a scan-fail safeguard that cuts output the instant the scanners stop moving
See FDA Laser Products and Instruments for current guidance.
BeamTracer Safety Tools
BT Laser Studio includes compliance visualization tools for content planning only:
Laser Clearance Reference
Preview clearance planes, screen-height controls, and beam rulers
3D Beam Viewer
Full venue preview with safety grid and human figure for scale
BeamTracer's safety tools are visualization aids for content planning only. They cannot enforce compliance, certify hardware safety, or replace a physical safety inspection by a Laser Safety Officer.
A beam that stops moving turns off
A laser that holds still puts all of its power on one spot. Every BeamTracer laser tool watches for that during output: when what you are sending settles into a dot that is not moving, the laser starts to fade after about 1.5 seconds and is dark by about 2 seconds. It relights by itself as soon as the output moves — you do not need to press START again. Lines and shapes are never blanked.
While the laser is held dark, an amber line under ARM in the Laser Output panel — or in the safety dock at the bottom of the app when a projector is attached — says so:
- Beam blanked: signal idle in OSC-1, where the cause is a scope signal that has stopped moving.
- Beam blanked: output not moving in Text to Laser, Image to Laser, AI Beam Creator, Animation Studio, the ILDA Viewer and Video to Laser Live.
Hover the line for the reason. The drawing on screen does not change; only the laser output is held back. This is a software safeguard, not a substitute for your projector's physical interlock, scan-fail protection and emergency stop.
Esc blacks out every laser tool
While a laser is connected, Esc is BLACKOUT in OSC-1 and every Laser Studio tool — the same as the button in the safety dock. It works while you are typing, with a dialog open and in fullscreen, a second press keeps the blackout on, and only RELEASE BLACKOUT on screen clears it; START is needed after that. Ctrl+B (⌘B on Mac) does the same. See keyboard control.
MIDI can only turn a laser off
You can map a MIDI pad or fader to LASER BLACKOUT or LASER STOP in any laser tool. MIDI has no way to arm a laser, start it, or raise its power — those stay on-screen actions. A blackout from a pad holds until you click RELEASE BLACKOUT, and START is still needed after that. A MIDI pad is not an emergency stop: test it before every show and keep the projector's physical interlock within reach. See MIDI blackout.
OSC can only turn a laser off
Show-control software such as QLab or TouchOSC can send /beamtracer/laser/blackout or /beamtracer/laser/stop to black out or stop the laser through an OSC bridge. There is no OSC address that arms a laser, starts it, or raises its power, so anything that can reach your bridge can black out the show but never light it. A blackout sent over OSC holds until you click RELEASE BLACKOUT, and START is still needed after that. An OSC message can be lost on the network, so it is not an emergency stop: send the cue once before every show and keep the projector's physical interlock within reach. See OSC blackout.
OSC-1 DAC Output Safety
When streaming from OSC-1 to a laser DAC:
- Start with PPS low — begin at 20K and increase carefully
- Use the DAC Simulator first — validate content without hardware risk
- Keep power low during testing — test at minimum power, increase only for performance
- An idle signal turns the laser off — when the scope signal stops moving, OSC-1 blanks the laser within about 2 seconds instead of holding a dot on one spot, and shows Beam blanked: signal idle. It relights when the signal moves. See When the signal stops
- Never leave unattended — laser projectors with live DAC output must be supervised at all times
- Emergency stop — know where the physical power switch and e-stop are before you start
Outdoor & Aerial Shows
Any beam that is not safely terminated and could enter navigable airspace brings the FAA into scope. Outdoor operators file a Notice of Proposed Outdoor Laser Operation (FAA Form 7140-1) under Advisory Circular AC 70-1B — typically at least 30 days ahead — and must obtain a letter of non-objection before the show.
Aiming a laser at an aircraft is a federal crime (18 U.S.C. §39A), carrying civil penalties, fines up to $250,000, and up to 5 years imprisonment. Never allow a beam to reach the sky near flight paths.
If Something Goes Wrong
- Stop immediately — blank or kill all output at the first sign of an unsafe condition.
- Seek medical care — if anyone may have taken a beam to the eye, get a prompt ophthalmologic exam. Sensor and camera damage can occur below the human-injury threshold, so a damaged camera is a warning sign.
- Report it — manufacturers must report accidental human exposure to the FDA CDRH using the Accidental Radiation Occurrence (ARO) report, Form FDA 3649. To report a show you believe is unsafe, contact the operator, the venue, the FDA CDRH, and your state laser agency.
Resources
- ILDA Safety Resources — International Laser Display Association
- FDA CDRH Laser Guidance — US FDA official page
- LSO Certification — Laser Institute of America LSO certification
- Laser show safety guide — the illustrated version for US shows