How is a flashback identified in welding?

Usually, you will hear a popping sound that turns to a whistle when this happens. Flashback: When a backfire takes place in a mixing chamber, unless you shut off the oxygen valve, the flame burning in the torch head may ignite gases in the hoses and result in a flashback.

What is a flashback flame?

A flame or flashback arrestor is a safety device designed to stop a flame in its tracks. It is therefore used to prevent flashback into cylinders or pipework. A flashback arrestor should not be confused with a non-return valve, which has no particular flame stopping properties.

What causes flashback in oxy acetylene?

A flashback happens when the torch tip close or fuel line pressure drops. When this happens the reverse flow mixes oxygen and the fuel gas (acetylene) in the same line. Backfire is caused due to holding the torch tip too close to the work or allowing hot slag to build up on tip.

How do you do a flashback?

Flashbacks can be triggered by a sensory feeling, an emotional memory, a reminder of the event, or even an unrelated stressful experience. Identify the experiences that trigger your flashbacks. If possible, make a plan on how to avoid these triggers or how to cope if you encounter the trigger.

What must be done if a flashback occurs?

If flashback occurs and the flame moves into the blowpipe, a shrill hissing sound will be heard. Close the blowpipe oxygen valve at once, then close the fuel gas valve. Note: This is the reverse of the normal shutting down procedure.

What is the difference between flashback and backfire?

SUSTAINED BACKFIRE: Flame enters into nozzle or torch and continues burning inside with a hissing or whistling noise. FLASHBACK: Gas with higher pressure flows back through the torch into the hose with a lower pressure.

Are flashback arrestors required by OSHA?

4. Why aren’t flashback arrestors required by law or in the U. S., OSHA safety regulation? Answer: OSHA has cited employers for failure to use flashback arrestors under the broad federal regulation 29 CFR 1910.252, failure to recognize the responsibility to provide for the safe use of gas cutting and welding equipment.

What is an example of flashback?

Examples of Flashback: 1. In a story about a girl who is afraid of heights, there is a flashback to a time when she fell off of the top of a playground as a young child. A story begins with a scene of a desolate, destroyed town, then flashes back to a time when the town was full of life and people.

How do welders prevent flashbacks?

There are several things you can do to help prevent flashbacks, fires and explosions:

1. If using acetylene, keep the pressure below 15 pounds.
2. Purge your hoses before lighting the torch.
3. Never light your torch with a mixture of fuel and oxygen.
4. Check valves should be installed on both torch inlets and operating properly.

Where do you put flashback arrestors?

To prevent flashbacks, flashback arrestors must be installed on the outlets of both regulators, and/or torch inlets.

What happens if you have a flashback in welding?

Preventing Welding Flashback. A flashback is an explosion that progresses through the torch, hoses, regulators, and into the cylinders. The consequence can range from a burst hose to a violent explosion of the regulator and cylinders.

What is a flashback arrestor and how does it work?

When a flammable mixture of fuel gas and oxygen or air is present in a gas line upstream of a welding or cutting blowpipe, flame can travel backwards in the form of flash back into the gas line, and there is the possibility of a serious accident. A flashback arrestor is a safety device designed to stop a flame in its tracks.

What is a flashback on a torch?

A flashback is when fuel gas is ignited or burns back behind your torch tip in oxyfuel cutting or welding. Can be caused by low oxygen pressure from the cylinder (empty bottle) or a problem with your tip (dirty or damaged). It could travel down your hoses but most torches have a flashback arrestor to stop this.

What is a flashback in a gas fire?

A flashback is always a consequence of a backfire in combination with a gas mixture in parts of equipment upstream from the mixing point. The gas mixture in the hose results from reverse flow when gas at higher pressure flows into a hose with lower pressure. a check valve that is not working properly.