What is the best fire extinguisher for Laser Cutting & Engraving in Australia?

I was contacted about the best type of portable fire extinguisher by a small business who had just purchased their first CO2 laser for cutting and engraving. I was curious, can a laser cause a fire? Well a quick google search revealed that YES, all types of laser can cause fires.

For those learning about lasers for the first time, I should point out that there are a few different types of lasers;

• CO2 Laser:
  • Well-suited for cutting, engraving, and marking non-metallic materials and some metals.
  • Common applications include woodworking, acrylics, fabrics, and more.
• Diode Laser:
  • Ideal for marking and cutting thin materials, including plastics and metals.
  • Often used in medical devices, consumer electronics, and automotive manufacturing.
• Fiber Laser:
  • Known for its efficiency in cutting, welding, and marking metals and some non-metals.
  • Utilised in heavy industry, aerospace, and electronics for its precision and power.

Lasers can be used for a wide range of applications such as laser pointers & range finders, laser levels & measuring tools, engraving & cutting, hair removal, cosmetic & general surgery, and CD/DVD & Blu-Ray Players.

Laser cutters and engravers work by concentrating a high-powered laser beam onto a material's surface, which either cuts through the material or alters its appearance for engraving purposes.

High-power lasers can cause fires due to the intense heat they generate when focused on combustible materials. The process by which a laser can ignite a fire involves several factors related to the laser's properties and the type of the material being targeted;

• Concentration of Energy – The laser beam focuses a significant amount of energy into a very small area. This concentration of light energy is absorbed by the material at the point of contact.
• Heat Generation – As the material absorbs the laser energy, it converts the light into thermal energy, causing the temperature of the material to rise rapidly. For cutting or engraving, this is desirable up to a point, as it allows the material to be melted, vaporised, or chemically altered.
• Ignition Point – If the temperature of the material increases beyond a certain threshold (its ignition or flash point) the material can spontaneously ignite, leading to a fire. The specific ignition point varies significantly among different materials, with some being more susceptible to laser-induced fires than others.
• Flammable Materials (fuel) – Certain materials that are inherently flammable such as paper, wood, certain plastics, leather goods and fabrics (Class A materials) are at a higher risk of catching fire when exposed to a high-power laser beam. These materials can quickly reach their ignition point and combust.
• Oxygen – The presence of oxygen plays a crucial role in combustion. Laser cutting and engraving, often done in open air, have an ample supply of oxygen, which can facilitate and sustain the burning process once a fire starts.
• Lack of Monitoring or Control – If the laser operation is not adequately monitored or if the laser settings (power, speed, focus) are not correctly adjusted for the material, the risk of fire increases. Overexposure to the laser beam can cause excessive heating and ignition.
• Accumulation of Combustible Materials – During the operation of a laser, combustible dust and other residues accumulate during the cutting or engraving process. If these materials are ignited by the laser or by an existing small fire, they can contribute to the uncontrolled spread of fire.

Considering the real risk from fire that comes with laser cutting and engraving, particularly when Class A materials are involved, it's absolutely critical for owners and operators to fit out their workspace with the correct fire safety equipment and follow the right protocols.

Top of the list? Getting your hands on the right kind of fire extinguisher. But, keeping fire risks at bay goes way beyond just having the right extinguisher on hand; it's about adopting a comprehensive approach that covers a range of safety measures and best practices.  Here is a checklist of good practices you can implement to keep your laser and property safe from fire;

• Regular Maintenance – Ensure the laser equipment is regularly maintained and inspected for any potential hazards. Ensure that waste material such as volatile organic compounds (VOCs) and tar among other substances is regularly cleaned from the cutting and engraving area.
• Fuel Load – Reduce & remove the fuel load by regularly removing offcuts, scraps, dust and other fuel sources (including flammable liquids) from the cutting and engraving area.
• Material Awareness – Understand the properties and ignition points of the materials (particularly Class A materials) being processed to adjust laser settings accordingly.
• Adequate Ventilation – Install effective ventilation systems to remove flammable gases and particles produced during the cutting or engraving process.
• Fire Safety Training – Educate yourself and employees about fire safety, including how to select and use the right type of fire extinguisher.

There are two good choices for the best type of portable fire extinguisher for your laser cutter and engraver.  These are;

• Dry Powder Fire Extinguisher;
• Carbon Dioxide (CO2) Fire Extinguisher;

A dry powder fire extinguisher is a versatile firefighting tool capable of tackling Class A, B, E fires, which makes it a seemingly suitable option for environments involving laser cutting and engraving.

However, the use of a dry powder extinguisher in a laser cutting setting is not without drawbacks. The residue left by the powder can be pervasive and difficult to clean, potentially infiltrating sensitive laser equipment and electronics, leading to corrosion or other damage.

In contrast, a CO2 fire extinguisher emerges as a superior choice for laser cutting and engraving operations. Unlike dry powder extinguishers, CO2 extinguishers are a three-dimensional agent and leave no residue, ensuring that laser equipment and electronics remain unharmed in the aftermath of a fire.

The CO2 gas works by displacing oxygen around the fire, effectively suffocating it without the mess associated with powder fire extinguishers or other extinguishing agents. This quality not only facilitates a quicker return to normal operations post-incident but also mitigates the risk of secondary damage to the precision tools and materials commonly found in laser cutting environments.

For maintaining both safety and equipment integrity, CO2 extinguishers offer a compelling advantage.  For this reason, in most circumstances, we strongly recommend the use of a CO2 fire extinguisher for your laser cutter and engraver.

For most small applications, the 2.0kg capacity CO2 fire extinguisher will be adequate.  Where the fuel load increases, the capacity of the fire extinguisher should also increase is an additional, very low cost precaution you could take.

This article explores the inherent fire risks associated with laser cutting and engraving, emphasising the importance of adopting comprehensive fire safety measures, to protect people and property from the risk of fire.

We highlight the potential of lasers to ignite fires, especially when interacting with combustible Class A materials, due to the concentration of energy, heat generation and oxygen.

To mitigate these risks, the we suggest regular maintenance of laser equipment, and the adjacent area including the management of fuel loads, understanding the properties of materials being processed, ensuring adequate ventilation, and providing fire safety training.

When it comes to selecting the best type of fire extinguisher for such environments, in most cases, we recommend purchasing a CO2 portable extinguisher mounted nearby as the superior choice for laser cutting and engraving operations.

CO2 extinguishers are popular because of their residue-free and efficient fire suppression capabilities, making them ideal for protecting sensitive equipment and maintaining workplace safety.