Oxyacetylene cutting

Oxyacetylene cutting equipment consists of an oxygen cylinder; a cylinder of fuel gas (acetylene or propane); two regulators; a mixing torch; a twin coupled hose, a non-return valve (check valve), an acetylene flashback arrestor as well as a cylinder carrying cart. Oxyacetylene cutting is a process for cutting metals using a mixture of oxygen and fuel or gas, which requires a torch to burn the metal into a metallic oxide that turns the groove into slag. The process will need two isolated supplies, oxygen and fuel/gas.

In the cutting process, the metal is preheated to a certain temperature (for steel, it is around 700°C – 900°C) without reaching its melting point. The process will cause a chemical reaction and form slag or iron oxide. Then the slag will be expelled by the oxygen jet, resulting in metal cutting.

In no way is it about generating fear in users. Muniriyathse (safety zone) firm intention is to make you aware that, like any industrial equipment that handles high pressures and temperatures, appropriate devices and procedures must be used to work safely.

In recent years, new and more economical flashback arrestor valves have been created, which have also already been integrated internally into the equipment, giving maximum safety during oxyacetylene cutting. Casual users benefit more from torches with safety features, such as built-in check valves and flashback arresters.

Oxyacetylene cutting hazards

Oxyacetylene cutting – This type of cutting is known as gas cutting or torch cutting. It is a widely used method to separate metals. This method is most often used for cutting steel. General risks arise in all Oxyacetylene cutting processes, such as:

• Fire and explosion: Leaky hoses, improper gas mixing, sparks, and overheated cylinders pose explosion risks. Burning metal and slag creates fire hazards.
• Health hazards: Exposure to toxic fumes, dust,  infrared radiation, ultraviolet radiation, smoke from burning metal, oxygen deficiency, and acetylene can cause respiratory problems, dizziness, and narcosis.
• Electrical hazards: Faulty equipment or live wires near the cutting area can result in electrical shock.
• Physical hazards: Flying sparks, molten metal, and falling slag can cause burns and injuries. Cylinder accidents due to improper handling can cause serious damage.
• Falls at different levels, depending on the cutting situation.
• Heat stress

May you like:

Welding hazards and precautions

Oxyacetylene cutting precautions

To control these risks, it will be necessary to:

• Training and certification: Operators must be trained and certified in safe oxyacetylene-cutting practices.
• Work environment: Ventilate the work area adequately to prevent fume build-up. Secure the workpiece and clear the area of combustibles.
• Safe practices: Follow proper torch lighting and extinguishing procedures. Use flashback arrestors. Never leave a lit torch unattended.
• Emergency preparedness: Have fire extinguishers readily available and know how to use them.
• The acetylene gauge keeps the pressure below 15 PSI.
• Install a check valve to stop the reverse flow of gases
• Install flashback arrestor to prevent flashback

Other precautions must be taken into account:

• Periodically check the Oxyacetylene cutting equipment to check its good condition.
• Never grease any part of the equipment, since in the presence of oxygen the lubricants become explosive.
• Do not use gas cylinders to blow dust from clothing due to the danger of acetylene and oxygen.
• In the event of a fire, quickly close the supply valves.
• Do not hit or drag gas cylinders.
• After a long stop or at the beginning of work, the pipes and the torch will be purged before applying the flame.
• Hoses of adequate length will be placed to prevent workers from falling.
• The bottles must have the cap properly fixed, and they will be stored, even empty ones, always with the valves closed and provided with their protector if their use is mandatory. Full and empty bottles will be stored in separate groups, vertically and secured to prevent them from falling. Before using a bottle, ensure it is well-supported to prevent it from falling.
• All equipment, pipes and accessories must be appropriate for the pressure and gas to be used in each application.
• When interrupting Oxyacetylene cutting work, the torch must not be hung from the bottle, nor should the bottle be heated. Flames will not be used to detect leaks. Sparks will be prevented from falling on the cylinders.
• Maintenance and periodic checks of the hoses to detect ageing and cracks.
• The gas cutter will always use a leather apron, protective mask, leather gloves, face shield and safety shoes.
• For more information, read the acetylene and oxygen SDS, which is attached as a document with a permit.

What are check valves or non-return valves?

However, ignorance of the actual operation of check valves has led some gas cutters to become overconfident, leaving them susceptible to other types of accidents, such as flashbacks. More than 90% of accidents are caused by the mixture of gases in the hoses, that is, checks valve reduce the probability of an accident by up to 90%. Check valves:

• Allow gas to pass in only one direction
• They prevent the gases, from possibly mixing in the hoses (if the oxygen and fuel mix and then ignite, they explode)

What is a flashback arrestor?

A flashback is a rare event, but when it occurs, it is difficult for a gas cutter to escape without injuries, since depending on the magnitude, the torch, hoses and regulators may explode. In extreme cases, cylinders have exploded.

Flame flashbacks are caused by poor gas regulation and incorrect application of nozzles (clogging the gas outlet during operation). The flame stops coming out of the nozzle and a very loud whistle is heard inside the torch, heating up in a matter of seconds and often melting the tubes, burning hoses and everything in its path, even the cylinders. If there is no interruption of the supply source, there may be an explosion.

Flashback arresters contain a sintered filter that prevents a flame from passing through the filter element. Flashback is the return of a flame to the torch, producing a popping sound. The last event is a sustained backfire. This is when a backfire occurs and the torch continues to burn. Flashback arrestor stops the reverse flow of flame, prevents reaching the flame into the acetylene cylinder and prevents explosion.

Conclusion:

By recognizing the hazards of oxyacetylene cutting and diligently following precautions, operators can work safely and effectively. Prioritizing safety through training, proper equipment, and safe practices protects individuals, prevents property damage, and ensures a productive work environment.

Remember, safety is paramount when working with oxyacetylene-cutting equipment. Taking the necessary precautions minimizes risk and paves the way for successful and injury-free operations.