When propane or butane is combined with air, flashback arrestors are not required. This is especially true with Bullfinch propane and butane appliances. The Bullfinch Autotorch for acetylene, as well as oxy-propane and oxy-acetylene systems, requires flashback arrestors.
Is it really necessary to use flashback arrestors?
A flashback arrestor, also known as a flash arrestor, is a gas safety device used to stop the flame or reverse the flow of gas back into the equipment or supply line in oxy-fuel welding and cutting.
It safeguards the user and their equipment against harm or explosions.
These devices are mostly utilized in industrial processes that handle and employ oxy-fuel gas mixtures.
Flashback arrestors are critical safety products for securing workplaces and working environments.
Wet flashback arrestors were also employed in the past.
Dry flashback arrestors with at least two safety elements are now the industry standard.
I’m not sure how many flashback arrestors I’ll need.
A backflow preventer will not always prevent a flashback from affecting the hoses, regulator, or cylinders. As a result, the safest and most favored type of protection is a flashback arrestor. Two arrestors or backflow preventers are required. One is connected to the fuel line, and the other is connected to the oxygen line.
What is the difference between a check valve and a flashback arrestor?
Valves and Flashbacks should be checked. Arrestors are safety devices used to protect employees who use oxyfuel cutting and welding machines. A check valve is a mechanism that prevents gases from flowing backwards unintentionally. A flashback (flame) arrestor is a device that stops a flame from spreading upstream.
What’s the difference between flash back arrestors and reverse flow valves?
Reverse Flow Check Valves: Helps to prevent gases from flowing backwards through the check valve. Flashback Arrestors: In the event of a flashback, prevents a flame from passing through the flashback arrestor.
When should you replace your flashback arrestor?
Pressure regulators should be tested annually and replaced or renovated every five years, according to a new SIRE version (7) issued by OCIMF in September 2018. The British Compressed Gases Association’s Code of Practice CP7 guideline recommends this, however manufacturers’ recommendations should also be heeded.
Although pressure regulators are designed for use with specific welding gases, all other equipment should be thoroughly inspected before to use. Various national safety agencies recommend placing flashback (flame) arrestors on both the cylinders and the workstation for further safety, especially where large lengths of piping between the cylinders and the blowtorch are involved.
Flashbacks can occur as a result of improper maintenance or the incorrect use of welding equipment, and long-term storage can degrade internal components and lead to leaks. Flashback arrestors, like pressure regulators, should be updated every five years.
Although the OCIMF regulations only apply to tankers and similar vessels, ship owners and operators should follow procedures to guarantee that their regulators and flashback arrestors are always completely functional and leak-free.
Ship owners should always choose equipment from reputed vendors when it comes to safety and compliance.
What are the different sorts of flashback arrestors?
There are two types of flashback arresters on the market:
Flashback Arresters That Are Wet (Hydraulic or Liquid)
The liquid used in these flashback arresters extinguishes the fire and prevents the reverse flow from reaching the source. They effectively stop fires from spreading throughout the pipe or hose. The liquid should not be combustible or absorbent. The liquid used in wet flashback arresters is usually ethylene glycol. The gas bubbles through the liquid, which aids in the extinguishment of the fire.
Wet or liquid flashback arresters come in a variety of sizes and should be sized according to the application’s flow requirements. These flashback arresters have a lengthy life span and are especially useful in large industrial setups.
Arresters in a Dry Flashback
Dry flashback arresters obstruct the passage of fire by using dry goods such as sintered metal or ceramic cartridges. Porous and powdery sintered material is required. This acts as a barrier and diffuser, preventing the flame from spreading. For the sintered material, a range of materials such as bronze wool, sand, and others can be employed. Sintered metal is the preferred material in professional setups.
In tiny portable applications such as welding or oxy-fuel cutting, dry flashback arresters are utilized. When compared to liquid flashback arresters, these arresters are smaller and lighter, and they are usually thrown away after a flash or replaced with a cartridge.
What is a FLASHBACK and why is it dangerous?
When a flashback happens, the flame burns quickly ‘upstream,’ usually resulting in a loud explosion. It can pass through the torch and into hoses, regulators, and gas bottles/cylinders if not monitored.
Flashbacks can be triggered by a variety of factors, including worn or inadequately maintained equipment, operator error, faulty cylinder pressure monitoring, and many others!
A flashback can result in anything from minor equipment damage to a massive gas cylinder explosion that results in death, injury, and/or substantial property damage.
Because there is no way of knowing how severe the effects will be, you must safeguard yourself against a flashback.
What is a FLASHBACK ARRESTOR (FBA) and what does it do?
A flashback arrestor is a device that is used to contain a flashback and keep it from reaching “upstream equipment” (e.g hoses, regulators and gas cylinders).
- Non-Return Valve: This valve prevents gas from flowing backwards (back surge).
- This is a sintered flame filter that prevents the flame from spreading.
- Cut-Off Valve with Thermal Activation: (fitted to regulator mounted models only). This valve will close and block the flow of gas in any direction if there is a persistent (continuous) flashback or backfire.
What are the current safety requirements?
Flashback arrestors are required by Australian standard AS4839-2001 (“The safe use of portable and mobile oxy-fuel gas systems..”). (see Clause 7.3). Flashback arrestors are now required by Health and Safety Authorities in all Australian states and territories as a result of this standard.
So….Why should I fit flashback arrestors?
“Can I afford not to install flashback arrestors?” you might wonder. If you don’t have flashback arrestors on your oxy equipment, you’re putting yourself at risk for a variety of things, including:
- Equipment and property damage, as well as personal harm and/or death, are all possible ‘physical’ repercussions of a flashback.
- Breach of Occupational Health and Safety / Workplace Health and Safety (OH&S/WHS) standards and requirements
- Litigation, insurance cover ‘disqualification,’ and other potential legal and financial implications of a flashback
So, how many flashback arrestors do I need, and where should I fit them?
According to Australian Standard AS4839-2001 (“The safe use of portable and mobile oxy-fuel gas systems…”), “Flashback Arrestors should be fitted to:
What gases require flashback arrestors?
Any oxy-fuel system, whether using oxy-acetylene or oxy-LPG, has the potential for flashback (oxy-propane).
Because flashback might happen on either the oxy or the fuel gas line, FBAs should be installed on both.
Are all Flashback Arrestors the same?
Here are some things to look for in flashback arrestors to ensure that they will protect you and perform when you need them:
AS4839-2001 (“The safe use of portable and transportable oxy-fuel gas systems…”) also mandates that all Flashback Arrestors be built in accordance with AS4603. This is critical because if an arrestor does not meet this criteria, there is no guarantee that flashback will be prevented!
Always check the labels on flashback arrestors before acquiring them, or if you already have them installed on your equipment, to ensure they meet Australian Standards AS4603. If you own flashback arrestors and can’t figure out if they’re compliant with AS4603, do yourself a favor and replace them. Dispose of them and replace them with Arrestors who are compliant.
FBAs must be tested by an independent qualified 3rd party to be compliant, according to AS4603. In most cases, if the FBA has been independently tested, it will be noted on the label or box.
Apragaz laboratory (Europe) independently tests and certifies Weldclass Flashback Arrestors, and this is clearly stated on the container and on the FBA itself.
Although a thermal cut-off valve is a critical safety feature, not all FBAs have one. If the internal temperature of the FBA reaches a harmful level during a sustained (continuous) flashback or backfire, this valve will close and block the flow of gas in any direction. If a protracted flashback occurs without this feature, the FBA is at risk of failing.
AS4839-2001 further requires that regulator-mounted Flashback Arrestors should feature a thermal cut-off valve for maximum protection. If the FBA has a thermal cut-off valve, it will be indicated on the label. This is sometimes indicated by a ” sign.
If there is no mention of a thermal valve on the label (on the regulator-mount FBA), you can presume it does not contain this safety feature.
Periodic Testing or Replacement
If you have flashback arrestors, you should be aware that Australian Standards AS4603 and AS4839 require that they be tested (or replaced) every 12 months and in the event of a flashback. Qualified repairers should do the testing.
