Laser Safety is a massive topic with many nuances, but in this post, we’re going to touch on some basics to help you have a better understanding and why it's necessary to hire a reputable firm like Coherent Designs to produce your laser show to avoid injury, damage to property, or fines.
Why Safety? It's just Light, right?: Lasers are such an incredibly vibrant, powerful source of light. There are many ranges of power output that lasers can produce. We measure this power in watts (W), or if less than a watt, we measure them in milliwatts (mW). The amount of power produced by the laser determines the type of class of laser, which then comes with a different set of rules. Today we’re going to focus on the highest class of lasers, class 4, as it’s the class that 99% of professional laser projectors fall into.
So what's the danger?: The intensity and concentration of the energy in the laser can pack a serious punch, with all the power concentrated in such a small area heat build-up can happen very quickly. That heat can then burn surfaces. With improper operation, property can quickly suffer burn marks, damage sensors in cameras, video projectors, and human skin. The most significant danger is that a laser beam can be smaller than the human pupil, allowing the full energy to enter the retina causing permanent black spots in vision or total loss of sight. These dangers increase with the increase of power in the beam.
Us Laws: In the US, the CDRH (Center for Disease and Radiological Health), a division of the FDA (Food and Drug Administration), regulates the use of lasers in public. They govern everything from the internal workings of a Laser Projector to how and where they are used. In Outside environments, the FAA also has a say in the use of lasers in the name of protecting pilots and air traffic safety. So what are these laws? Let's go over a few of the basics
Distance from the public: US law dictates that all laser beams must stay 3 meters above the ground on which it is reasonably expected that public can access and 2.5 meters horizontally.
Emergency Stops: Emergency stops, or E-Stops for short, are a big red button to allow the operator to immediately stop the output of the laser if something were to go wrong
Paperwork: To help regulate and police the industry, The CDRH requires all Laser show companies to carry a Variance. Without one, a company is operating illegally. A variance is a document acknowledging the approval of the government for the company to operate the lasers in a safe and legal manner in public. It also provides stipulations on which CDRH approved Lasers the company may use and the types of uses that particular company may use them for. Variances can expire without proper yearly submission of post show reports or be pulled due to not following laws or a safety incident. Variances are not “rentable” or transferable, meaning we could not rent a laser for a customer to use on their own without a Coherent Designs employee on-site during use monitoring all safety aspects and having final control of the E-stop. However, if a customer were to have a variance of their own, dry rentals of lasers is possible.
Signage and labels: The CDRH wants people that may come into the vicinity of lasers to know of their presence. Warning Signs are required to be located near all entrances of the area that the laser is within the minimum distances required for public safety. These signs are supposed to let people know they have the potential to be exposed to harmful beams. Labels are required on the projectors themselves to let people know where the aperture that the beam will output from. Along with labels on the projectors, it is required to have what is known as an emission indicator. This is a little light located near the aperture to let people know that the laser has power and is capable of outputting laser at any moment. A warning light per se.
The Federal Aviation Administration?!: Lasers can pose a huge risk to flight operations, causing flash blindness during a critical phase of flight such as take-off and landing or even causing injury to the pilot. You may have heard news stories of people being arrested, jailed and fined heavily for just pointing a handheld low wattage laser at an aircraft. Outdoors Laser shows are classified into two types: terminated and unterminated. Terminated shows are when the beams stop on a surface. Unterminated refers to a show where the beams enter open airspace to continue on out into the sky. When doing unterminated shows, the FAA requires the laser show company to file ahead of time the types of lasers, where they will be located, the direction and angle of where they’ll shoot, and the time frame they’ll be operating. The FAA requires this in advance as they’ll then do a study of the area, what the expected flight traffic will be to make a determination if the show will have a detrimental effect on flight operations. The FAA then will approve or deny the laser show from happening. During the show, the operator is required to be reachable by Air traffic control in case a need arises for them to shut down the show along with being on the lookout for aircraft in the area.
While this isn’t meant to be fully comprehensive, as each one of these topics has their own individual rabbit holes we can dive into, this hopefully lays out a solid foundation to help understand why its important to use safe laser vendors to avoid a lot of harm and legal troubles.