Laser safety

The majority of lasers that are used in clubs and pubs are Class 3B lasers. These may emit visible radiation at an output power of less than 0.5 watts or 500mW. Direct intrabeam viewing of the devices is hazardous. As are reflections from metal, glass or mirrored surfaces.

The person responsible at the club or venue must show under Section 2 and 3 of the Health & Safety at work act 1974 and have sufficient information in the form of sketches, calculations and radiometric measurement data.

All display laser products shall be operated at all times under the direct supervision or control of an authorised trained operator, who shall maintain constant surveillance of the laser effect and immediately terminate the emission of laser radiation in the event of equipment malfunction, audience unruliness or other unsafe conditions. If the laser is left unsupervised, it must not exceed the accessible emission limit for a class 3A laser (2.5mW per sq cm) at any point less than 6m above anywhere the audience may stand.

The Laser class is not a measure of the Laser power. It is a measure of how dangerous the equipment is. For an example a 1-watt laser diode could be class 1 laser if it was completely safe and no laser light came out of the device, as in your blue ray player where the laser is enclosed. However beam power is the main factor that differentiates between ; class 3A output powers of less than 5mW, 5/1000 watts: a 3B laser output less than 500mW or 1/2 Watts : and a class 4 laser is above 1/2 a watt : Class 4 lasers are capable of damaging the eye if looking at the reflections from a non mirrored surface like paper as well as from mirrors and direct viewing of beam. They can also cause a fire hazard due to the power of the light beam. Their use requires extreme caution.

Laser power in Laymans terms

  • Class 1: beam is invisible, really safe, no use for displays though.
  • Class 2: reasonably safe, not for use by children or idiots.
  • Class 3A: reasonably safe if under competent control and sensible audience.
  • Class 3B: hazardous, must only be used by a trained user. This laser can cause blindness.
  • Class 4: these can burn skin, remove tattoos, cause fires. Blindness can result even by looking at the reflection from paper, that is if it does not set fire to the paper. These lasers are too powerful for nightclubs and should only be used for arena sized venues.

Once, I saw two class 4 lasers in use in a club and the system was left unmanned. The beam deflection was acheived by sending the right sound channel to one scanner and the left audio to the other axis scanner. This laser produced a chaotic squiggle throughout the club at full power, endangering everyone with its dangerous beam. I was out of that club within minutes.

It was incidents like that that made us start this web site. The music industry should be enjoyable and safe for both sides of stage or bar, not a place where people electrocute, blind or deafen themselves.

The pointing of any laser into the audience is potentially hazardous and only class 3A lasers can safely be used for audience scanning, providing the eye does not receive more than 2.5 mW per sq cm.

Smoke can reduce the energy in the beam as it gets reflected, refracted and absorbed by smoke particles in the beam. Audience effects should always be done through smoke. Also, without smoke the beam is invisible and the whirls of the smoke in the laser beam are part of the effect. To enable us to scan the audience we use a graduated filter with our lasers so the beam reduces power the nearer it gets to the audience. The laser beam must never stop moving and remain at a single point for more than 1/100 of a second.

I was at a nightclub watching someone else's laser display when suddenly the beam stopped moving and pointed straight ahead. The first beam steering mirror had fallen off and the design of the laser mirrors allowed a stationary beam to exit the laser on fault. Luckily the operator was a professional and the laser was quickly switched off. We have designed our lasers with this in mind and this failure cannot happen on our systems.

So, don't stare into club lasers unless you are on the run from the feds and need to disguise your retinal scan.

You have been warned. A 500mW laser could light a cigarette at 40 ft, most lasers in big clubs are between 500 mW and 2 watt.