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What Every Job Shop Should Know When Working With Lasers

June/July 2012

Get the basics and keep your employees safe

When deciding to purchase a laser, the most important thing is not figuring out which system offers the most power and speed for the money, but how to integrate it into your shop in the safest way possible to protect your employees.

Lasers have the potential to be very dangerous and if not handled properly, can result in serious injuries for those working with them or around them. No conscientious shop owner would wish this for his employees, so it’s important to be educated on the latest safety standards.

Gus Anibarro, education director for the Laser Institute of America, aims to do just that for laser end users, sharing his expertise on the main safety hazards of lasers and how to recognize them, as well as what the best standards are to follow and what other potential benefits they might offer beyond safety.

FSMD: What are the main safety concerns when dealing with lasers and laser optics?

ANIBARRO: The issue is really exposure to the laser beam. Some laser beams can be harmful enough that they exceed a safe limit that our bodies can handle. Essentially, the two structures of the body that we’re concerned with are, of course, the eye, because it’s a light-gathering organ, and then the skin – with the more powerful lasers, the skin can be burnt, as well.

The other issue in regard to laser safety is what we call non-beam hazards. A non-beam hazard is a hazard that is not directly related to the beam – it’s a secondary effect of the laser beam striking a surface, which would be a metal surface in our case. The smoke that a laser generates cutting through steel is a non-beam hazard, and it can contain laser-generated air contaminants – toxic gases or aerosolized particulates. These can be inhaled deep down into the lungs and can’t be removed. The toxic gases can also cause asphyxiation or potentially burn the interior of your lungs.

FSMD: What are the safe limits for exposure to the body?

ANIBARRO: As far as those limits go, they’re values of what we call irradiance or radiant exposure. Irradiance is the amount of power passing through an area, which is measured in the number of watts per square centimeter. Radiant exposure is the amount of energy passing through an area, and that’s measured in joules per square centimeter. That being said, the exposure limits are what we call the maximum permissible exposure, or MPEs. We don’t want to exceed a certain MPE for a certain wavelength, but what exactly is the safe limit? It’s not something in which we can say, “Oh, 20 watts per square centimeter. If you don’t exceed that your eye will be fine.” It’s not quite that simple.

MPEs are basically based on wavelength and exposure duration. There are other things that are involved with calculating an MPE, but for the most part we need to know the wavelength and the duration of exposure that the eye or skin received to come up with an MPE. There isn’t one number that you can say and you know you’ll be safe – it doesn’t work that way. But once you get your laser system into your facility, you can use the ANSI standard to figure out what its MPE is, based on what wavelength you’re going to use as well as a few other factors.

The MPE calculation in laser safety is very critical, because if you get it wrong, it could also lead to other problems. An incorrect MPE calculation will also lead to incorrect calculations for the nominal hazard zone, optical density and, in some cases, the classification of the laser. Therefore, it’s very important to get that right.

FSMD: Whose responsibility is it then to ensure safety when working with the laser?

ANIBARRO: Ultimately, the responsibility for laser safety rests with employers. The OSHA Act dictates that it’s up to them to provide a safe environment for their employees to work in that’s free of recognized hazards, and a laser system coming into the facility is a recognized hazard.

To ensure safety, employers can appoint someone as a laser safety officer. That person could be the laser operator, someone in environmental health and safety or any number of others – the ANSI standard doesn’t restrict who it can or can’t be. It does dictate, however, that you have to appoint a laser safety officer for lasers that are considered hazardous, which are class 3B and 4 lasers. After appointing the laser safety officer, that person needs to be trained, which is one of the things that the Laser Institute of America can do for you.

Another thing employers should do is to follow the ANSI Z136.1 for the Safe Use of Lasers Standards. The Z136.1 standard was created by an ANSI consensus committee with support from the Laser Institute of America. It’s a wise thing for employers to follow for the safe use of lasers, because the body of the standard was put together by people who work with hazardous lasers. From their experience, they’ve determined that this is probably the best way to implement a safety program and keep people safe.

Finally, employers should also make sure that they’re buying a laser that complies with the Federal Laser Product Performance Standard, as dictated by the FDA’s Center for Devices and Radiological Health, or CDRH for short. All laser manufacturers selling their equipment in the U.S. have to comply with this standard, and it ensures that all the reasonable safeguards for the laser system are in place. I would recommend not purchasing a laser system that doesn’t comply with this standard.

FSMD: How would a job shop purchase the ANSI Z136.1 standard?

ANIBARRO: A job shop can purchase a paper copy of that ANSI standard directly from the Laser Institute of America. If they want an electronic copy, like a PDF, they can go to ANSI and get that from them.

FSMD: What else can employers do to ensure the safety of their employees?

ANIBARRO: Employers might want to, through their laser safety officer, not only train their employees that are actually operating the laser, but train other staff that might not necessarily be operating the laser, but might be working in its vicinity. With a big manufacturing plant, for example, there may be other things going on and people that are working in other areas and with other things or pieces of equipment that have nothing to do with the laser, but may pass through the area where the laser is. So to help them to protect themselves, you need to get those people trained. And the laser safety officer is one of the people that’s given, through the employer, the authority and the responsibility to train these people.

Now, the LSO doesn’t necessarily have to be the one that actually administers the training, however. They can if they want, or they can have somebody else do it for them. They can hire an outside company to come in and do it, they can buy a DVD of some sort, or they can do it in collaboration with their facility’s training department.

Providing that kind of training goes a long way, because if everybody is aware of the hazard, then they know what to look for and they know when to follow certain procedures.

FSMD: What sorts of benefits might a job shop reap when they follow the proper safety procedures?

ANIBARRO: There could be some benefits in the way of insurance. We’ve had some people from insurance companies come and take our flagship laser safety officer with hazard analysis course – about four or five of them have attended over the past five years. And I’ve asked them, “Why are you here? You’re from an insurance company – you don’t use lasers!”

They’ve all told me that they were about to insure facilities that contain laser systems that are considered hazardous – they’re Class 4, and that’s the most hazardous class you can get – and to properly insure them, they wanted to know more about what the safety is behind a laser. They said that by finding out more about the safety, it could help reduce the cost of insurance to the facility.

So that’s another side benefit that comes out of implementing a good safety program, that is, the possible insurance reduction. Now how much will that reduction be? I get that question from time to time, and that’s something that I can’t answer, since I don’t work for the insurance company.

Conclusion
Laser safety is not incredibly complicated, yet it’s highly important. Following the ANSI standard for laser safety might be one of the best things that a shop owner can do for their shop and employees. And though it might represent a weighty initial time investment, the benefits that it yields will continue indefinitely.

Laser Institute of America