Class 4 Laser Systems:
Pass-Through and
Customer Responsibilities

Class 4 laser systems offer increased flexibility to users, but with that increased flexibility comes increased responsibility. As a Class 4 laser owner, it is critical to understand the safety requirements, operational procedures, and your obligations to ensure a safe environment for all users.

Pass-Through

The Fusion Ascent’s pass-through opens a whole new world of opportunity. With the front and rear doors open, you can feed oversized materials straight through the machine including long boards, full-length skis, oversized signage, architectural pieces, and other oversized pieces, that would otherwise be impossible to engrave on. It means you are no longer constrained by the footprint of the work area, which is a huge deal when a customer walks in with a 6-foot wooden plank or a custom piece that doesn’t fit the mold. For shops that want to take on more diverse, high-value jobs without investing in a much larger machine, the pass-through feature turns the Ascent into something far more versatile than its cabinet size would suggest. But this feature does involve increased risk, and therefore increased safety procedures.

At Epilog Laser, safety is at the core of everything we do.

All Epilog Laser systems are manufactured as Class 2 systems. The laser beam path is fully enclosed and inaccessible to users during normal operation. Our systems are classified as Class 2 (rather than Class 1) due to the integrated red dot pointer. For select models, users may purchase a Class 4 Conversion Kit. Once installed, the laser beam path is no longer enclosed, and additional safety protocols and user responsibilities apply for safe operation of the system. Installing the Class 4 Conversion Kit enables the pass-through feature.

The table below outlines the classification of laser systems according to ANSI Z136.1:

Class 1	Any laser or laser system containing a laser that cannot emit laser radiation at levels that are known to cause eye or skin injury during normal operation. This does not apply to service periods requiring access to Class 1 enclosures containing higher class lasers.
Class 2	Visible lasers considered incapable of emitting laser radiation at levels that are known to cause skin or eye injury within the time period of the human eye aversion response (0.25 seconds).
Class 3	Lasers similar to Class 2 with the exception that collecting optics cannot be used to directly view the beam
Class 4	High powered lasers (visible or invisible) considered to present potential acute hazard to the eye and skin for both direct (intrabeam) and scatter (diffused) conditions. Also have potential hazard considerations for fire (ignition) and byproduct emissions from target or process materials.

Know the Risks. Own the Responsibility.

Operating a Class 4 laser means you are exposed to more risks than a fully enclosed Class 2 system. Class 4 systems can present serious hazards if not managed correctly. To operate a Class 4 laser system, there must be a dedicated Laser Safety Officer (LSO) responsible for managing those risks. The Laser Safety Officer (LSO) is legally and ethically responsible for identifying risks, implementing safety measures, and ensuring proper training.

Hazards include but are not limited to:

Eye Injury:

Direct or scattered laser radiation can cause permanent eye damage.
Skin Injury:

Burns from direct or scattered beams.
Fire/Smoke:

Combustion risk; ensure ventilation.
Electrical/Fume Hazards:

Occur during servicing or material vaporization.

What You’re Responsible For

When purchasing a Class 4 Conversion Kit from Epilog, the responsibility for safety compliance lies with you, the end user.

You must have a Laser Safety Officer (LSO) who is solely responsible for the safety and operation of the Class 4 laser System. Those responsibilities include but are not limited to:

Implementing proper controls such as warning lights, barriers, and signage.
Ensure Personal Protective Equipment (PPE) such as laser safety eyewear is worn when operating the laser.
Provide and document training for all personnel who will operate or be exposed to the system.
Comply with local, state, and federal laser safety regulations.
Establish procedures for emergency shutdowns and routine maintenance.

To read more about LSO responsibilities kenteklaserstore.com/what-is-an-lso

Laser Safety Officer (LSO) Training

It is the user’s responsibility to ensure that a qualified LSO completes recognized training and fulfills requirements and standards across different international regions.

Epilog relies on a third-party partner to provide users with the opportunity to complete LSO training at no additional charge. To complete the Epilog-provided course, go to https://certification.epiloglaser.com/ and create an account. Once logged in, the user will have access to the course video and quiz. After successful completion, an LSO certificate of completion will be issued.

LSO Training

What Comes in the Class 4 Conversion Kit?

Epilog provides an optional Class 4 Conversion kit. The kit includes:

Class 4 Safety Labels
Class 4 Certification Tag
Class 4 Hex Key
Class 4 Enable Dongle
CO2 Laser Safety Glasses
Workpiece Risers
Class 4 Supplemental Manual

Reference Standards and Regulations

United States Standards

OSHA Regulations

29 CFR 1910.133: Eye & Face Protection requirements for laser hazards.
29 CFR 1910.132: General PPE requirements for hazard assessment and protection.

FDA Regulations

21 CFR 1040.10 / 1040.11: Performance and labeling standards for laser products.
Laser Notice No. 56: Aligns U.S. compliance with IEC 60825-1:2014 3.

ANSI Standards

ANSI Z136.1-2020: Core standard for safe laser use (hazard evaluation, controls, PPE, training).
ANSI Z136.4-2020: Measurement and hazard evaluation.
ANSI Z136.7-2020: Laser protective equipment testing.
ANSI Z136.8-2020: Guidelines for R&D environments.
ANSI B11.21: Machine tool safety requirements for lasers.

International Standards

IEC / EN Standards

IEC 60825-1:2014 (Ed. 3): Global benchmark for laser product safety (classification, labeling, controls).
EN 60825-12014: : EU harmonized version with additional requirements.
EN 50689: Consumer laser product safety in EU.

EU Directives & CE Marking

Machinery Directive 2006/42/EC: Requires CE marking and essential safety measures.
Low Voltage, EMC, RoHS directives may apply to electrical and emission characteristics.

ISO Standards

ISO 11553-1/-2: Safety requirements for laser machining systems.
ISO 11252: Documentation and labeling requirements for laser devices.

Important Reminder

Class 4 lasers are not fully enclosed systems. They require an informed, proactive approach to safety. Failure to follow proper procedures can lead to severe injury, property damage, and noncompliance with safety standards.

Operating a Class 4 laser is an opportunity that demands responsibility.

Class 4 FAQ

What is a Class 4 laser machine?

A Class 4 laser machine is the highest classification of laser under international safety standards. It poses a potential risk of injury to eyes and skin from direct, scattered, or reflected exposure.

How do I enable Class 4 operation on my laser machine?

To enable Class 4 operation on your laser machine, you will need to purchase the Class 4 conversion kit, complete the Laser Safety Officer training, and then install the conversion kit. Instructions for conversion can be found in the Class 4 Supplemental Manual that comes in the conversion kit.

How do I enable the pass-through feature on the Fusion Ascent?

The pass-through feature is enabled by installing the Class 4 Conversion Kit.

Why do I need a Class 4 conversion kit?

Epilog Laser machines are shipped as Class 2 laser systems to ensure safe operation for all users right out of the box. However, enabling the pass-through slot for oversized materials introduces additional laser safety risks. To meet safety regulations and maintain compliance when using pass-through, a Class 4 Conversion Kit is required. This kit includes the necessary components and documentation to safely upgrade your machine for advanced use.

Do I need a Laser Safety Officer (LSO)?

According to regulatory guidance, facilities operating Class 4 lasers must designate a Laser Safety Officer responsible for implementing and enforcing laser safety procedures.

Is it safe to operate a Class 4 laser machine?

When used properly and in accordance with safety protocols, Class 4 laser machines are safe to operate. Operators must follow all procedures and guidelines provided by their Laser Safety Officer.

Do I need laser safety training to use this machine?

Yes. Anyone operating or maintaining a Class 4 laser machine must receive proper training on laser safety protocols. This includes understanding hazards, using personal protective equipment (PPE), and following emergency procedures. Refer to your Laser Safety Officer for these procedures.

What kind of protective eyewear is required?

Laser safety glasses that match the wavelength and optical density requirements of the laser machine must be worn at all times when the laser is operating in Class 4. Kentek supplies Laser Safety Glasses for various wavelengths and optical densities. When purchasing additional sets of laser safety glasses, ensure they provide adequate optical density for CO2 lasers operating at 10.6 micrometers and are marked with their optical density rating and wavelength range. Verify that glasses are certified to ANSI Z136.1 or equivalent international standards. Consult with your Laser Safety Officer to determine the appropriate specifications for your specific application.

What support resources are available?

We offer detailed safety documentation and training videos so that your Laser Safety Officer is properly trained on safety and compliance. However, we cannot answer questions related to the safe operation of the laser machine within your environment. Refer to your Laser Safety Officer or our partner Kentek for questions of that nature.

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Class 4 Laser Systems:Pass-Through andCustomer Responsibilities