0:01 Welcome to the Coherent Laser Safety Awareness Training video. Before we begin,
0:06 please note the copyright laws that govern this
0:08 program. If you wish to pause this video, you may do so at any time.
0:24 Introduction to Laser Hazards
0:27 Hi there! Thank you for enrolling in laser training at Coherent. We are very excited
0:32 to have you, as you will be training on either a Class 3 or Class 4 laser
0:37 that can cause serious injury, blindness, or loss of life. We would like to inform you of
0:41 safety practices to ensure you remain safe during and after our training.
0:46 Hazards in the laser lab fall mainly into two categories:
0:49 laser beam hazards (including associated ion, skin safety) and non-beam hazards,
0:55 which include fire, particulate, chemical, asphyxiation, biological, mechanical,
1:00 and electrical hazards. I am here today to talk to you about those hazards and how to avoid them.
1:06 At the end of the video, there will be a short quiz to ensure you understand the
1:10 safety protocols that must be exercised around lasers. You must pass with an 80%
1:16 or better to attend the laser training session. Sit back, take notes, and good luck on your quiz.
1:24 Types of Eye Injuries
1:26 With any laser, the greatest safety concern is eye protection because a laser beam can
1:30 be many thousands of times brighter than the sun. Laser exposure to the eye, even for only
1:35 a fraction of a second, can cause permanent eye damage, including blindness. The three areas of
1:41 the eye most susceptible to laser damage are the cornea, the lens, and the retina:
1:46 The Cornea: A transparent tissue layer covering the front of the eye. Damage
1:51 to the outer surface of the cornea may be uncomfortable and painful but will
1:55 usually heal. Deeper layer corneal damage, however, can be permanent.
2:00 The Lens: Focuses light to form images on the retina. With age, the lens usually
2:05 becomes cloudy and can eventually progress to opacity, a condition known as cataract.
2:11 The Retina: The inner lining on the back of the eye that contains photosensitive elements. A
2:17 part of the retina that provides central vision is called the macula. The small depression in
2:22 the center of the macula is the fovea, which provides high-resolution, detailed vision.
2:31 Different wavelengths damage different parts of the eye:
2:34 Wavelengths in the mid and far IR, as well as the mid-UV, affect the cornea.
2:39 Near-UV wavelengths that fall in the range of 315 to 390 nm will damage the lens.
2:46 The most dangerous wavelengths to the eye are those focused onto the retina. This range, called
2:52 the ocular region, includes both the visible and near-infrared ranges (400 to 1,400 nm).
2:59 The cornea and lens have a focusing capability of 100,000 times, making it
3:04 easy to understand why even a low-power beam can produce catastrophic damage to the eye.
3:11 One common misconception is that bright light does the most damage to the eye. However, this is not
3:18 true. For instance, green light is perceived as the brightest, but faint light with a wavelength
3:27 of 800 nm—perceived at only 1-2% of the actual beam—can still cause significant harm. High-power
3:32 laser beams of light at higher or lower wavelengths may be invisible altogether,
3:37 contributing to misperceptions of output power and causing eye injuries. This is because the
3:43 eye’s blinking reflex to bright light only occurs for a narrow range of the spectrum.
4:07 For example, notice in this clip that you cannot see the laser beam burning marks
4:12 on metal. The light visible is from the heated metal, not the laser beam.
4:17 Laser Classifications
4:19 Lasers are mainly classified by two factors: wavelength and power. This is because
4:24 different wavelengths penetrate the skin and eyes differently, and power determines the intensity.
4:30 During this training, you may work with Class 3 or Class 4 lasers.
4:35 There are two types of classification systems: the Code of Federal Regulations (CFR) and the
4:41 International Electrotechnical Commission (IEC). Lasers can be classified by one or both systems:
4:53 CFR Classifications: Use Roman numerals.
4:56 IEC Classifications: Use Arabic numerals.
4:59 The classifications overlap but differ in some areas. Here are the classifications:
5:05 Class 1: No hazard during normal use. Examples include laser printers and compact disc drives.
5:19 Class 1M: Safe under normal use unless magnifying optics (e.g., microscopes) are used.
5:35 Class 2: Visible lasers (400-700 nm) with up to 1
5:41 mW of output power. Momentary viewing is not considered hazardous, as the eye will
5:47 blink within 0.25 seconds. Intentional extended viewing, however, is hazardous.
6:04 Class 2M: Similar to Class 2 but with large diameter or
6:05 divergent beams that are safe unless viewed through optical instruments.
6:23 Class 3: Includes subcategories 3A,
6:26 3B, and 3R. These lasers can be hazardous under direct exposure:
6:29 Class 3A: Visible lasers with 1-5 mW power. Examples include laser pointers.
6:57 Class 3B: Hazardous with direct exposure. Diffuse reflections from matte surfaces are not harmful.
7:34 Class 3R: Safe if handled carefully, with restricted beam viewing.
7:56 Class 4: The highest hazard level. Can cause instantaneous damage from direct
8:02 exposure or reflections. Most commonly used in training labs.
8:45 Safety Standards and Regulations
8:48 Coherent lasers comply with the American National Standards Institute
8:53 (ANSI) and the Occupational Safety and Health Administration (OSHA).
9:00 Additional compliance includes the Code of Federal Regulations (CFR), IEC, CSA,
9:10 TUV, and UL guidelines. Universal symbols for danger, warning, caution, and notice are used:
9:22 Danger: Will cause death or injury.
9:26 Warning: Could cause death or injury.
9:29 Caution: May cause minor or major injury.
9:34 Notice: Possible damage to equipment.
9:39 Always refer to the safety section of the operator manual for your laser system.
9:58 Protective Eyewear
10:03 Proper laser safety eyewear is crucial. Your instructor will provide the correctly rated
10:12 eyewear. Ensure your eyewear fits well, provides front and side protection, and is free of
10:33 scratches. Eyewear must be marked with wavelengths and optical density (OD) values for the specified
10:38 wavelengths. Ask your instructor or Laser Safety Officer (LSO) for recommendations if needed.
13:09 Safe Work Practices
13:12 Basic tips for staying safe in a laser lab:
13:15 Keep lasers on stable surfaces with beams parallel to the ground and below eye level.
13:22 Avoid chairs, as sitting may bring your eyes into the laser beam plane.
13:32 Minimize exposure by limiting time, intensity, and maintaining a safe distance.
13:38 Key terms:
13:44 Maximum Permissible Exposure (MPE):
14:01 The highest safe dose of laser radiation without adverse effects.
14:43 Optical Density (OD): Represents attenuation of the laser beam by eyewear or filters.
15:07 Nominal Hazard Zone (NHZ): The distance within which exposure exceeds the MPE without protection.
15:27 Remove metallic or reflective jewelry to prevent unintended reflections and
15:44 injuries. Protect your skin as it can also be damaged by lasers.
15:52 Additional Hazards
15:53 Electrical: Water near electrical components can cause lethal hazards. Immediately turn off power
18:31 in case of leaks.
18:44 Fire: Ensure proper enclosures, inspect equipment, and have fire extinguishers available.
19:02 Asphyxiation and Chemical Hazards: Use directed ventilation
19:35 and appropriate protective measures when working with hazardous materials.
19:54 Mechanical Hazards: Be aware of
21:07 heavy tools, sharp objects, and high-pressure gases. Wear fully enclosed shoes.
22:33 Emergency Procedures
22:40 Your trainer or LSO will inform you
22:44 of emergency procedures. Follow instructions and know the location of safety equipment.
22:47 Interactive Elements
22:50 After viewing this video, take the quiz. An 80% passing score
23:06 is required for certification, which is valid for one year.
23:18 Summary and Review
23:19 Remember: Laser beams can injure without being visible.
23:25 Always wear proper eye protection.
23:27 Be aware of other hazards, including fire, electrical, chemical, and mechanical risks.
23:58 For additional information, contact your instructor or the Coherent product support
24:48 hotline. Thank you for watching, and we hope you found this video informative.
