Safe use of oxygen cylinders
Transport
- When transporting oxygen cylinders, wear a safety helmet and tighten the cylinder protection ring.
- During transportation, handle cylinders with care to avoid collisions when loading or unloading them.
- It is strictly forbidden to roll the cylinders on the floor or drop them from a height.
- Furthermore, fuels, grease and any items with oil stains should not be transported together with oxygen cylinders to avoid possible dangers.
Deposit
- The oxygen cylinder must be protected from sunlight, high temperatures, open flames and metal splashes.
- Flammable products cannot be stacked within 10 meters.
- The oxygen cylinder must be stored in a vertical position, with the cap screwed on to prevent grease and dust from entering the cylinder mouth. It must also be protected with railings and supports to prevent tilting.
- The oxygen cylinder must be kept at least 1 meter away from the radiator and other heat sources.
Use
Before installing the pressure reducing valve, slowly open the cylinder valve, remove any dust inside and outside the interface, install the pressure reducing valve, and then open the valve for inspection.
◆ People should not face the interface on the side of the interface during operation.
◆ Check whether the leather tube joint is free from dust and metal chips before connecting.
◆ After removing the leather tube, do not place it facing the sky or the ground to prevent impurities from entering.
◆ Do not completely exhaust the oxygen in the bottle; Allow 1-1.5 atmospheres to facilitate air wash inspection and prevent impurities from entering.
◆ In winter, only use hot water or steam to defrost the bottle valve. The use of a flame for heating or an iron hammer is prohibited.
◆ When working in the same area as an electric welder, insulating pads should be added to the bottom of the cylinder to prevent electrification of the cylinder.
◆ Metal pipes and equipment in contact with gas cylinders must be installed with grounding wires to prevent static electricity from causing fire and explosion.
17 Gas Cylinder Safety FAQs
1. Why should acetylene cylinders be kept upright instead of lying flat when they are stored and used?
There are four reasons:
There are several reasons why acetylene cylinders must be placed vertically.
Firstly, the cylinder contains acetone, which is a filler and solvent. When the cylinder is used horizontally, acetone can easily flow with acetylene gas, leading to increased acetone consumption and reduced combustion temperature.
This can backfire and cause an explosion accident. The acetylene in the cylinder is dissolved in acetone solvent under pressure. When the valve is opened, the pressure decreases and the dissolved acetylene becomes a gas and is released.
Acetylene cylinders placed horizontally can cause acetone to flow out, and this can quickly volatilize and mix with air to form an explosive mixture. The explosion limit is between 2.3% and 72.3% (vol), and the minimum ignition energy is 0.019mJ. In case of open fire and thermal energy, combustion and explosion may occur.
Secondly, when acetylene cylinders are placed horizontally, they are prone to rolling and can easily impact other objects, creating excitation energy that can cause accidents.
Thirdly, acetylene cylinders are equipped with shockproof rubber rings to prevent collisions during loading, unloading, transportation and use. The rubber ring is an insulating material, which means that the acetylene cylinder must be placed horizontally on an electrical insulator to prevent the static electricity generated in the cylinder from spreading to the ground.
If static electricity builds up in the cylinder, it can easily generate static sparks. When acetylene gas leaks, it can cause combustion accidents and explosions.
Finally, when using an acetylene cylinder, the valve must be equipped with a pressure reducer, flame arrester and rubber tube. As the cylinder tends to roll when lying down, it can easily damage the pressure reducer, flame arrester or tear off the rubber tube, causing acetylene gas to leak and causing combustion and explosion accidents.
In conclusion, acetylene cylinders must be placed vertically to avoid accidents caused by acetone flow, rolling, static electricity and equipment damage.
2. Do oxygen cylinders need to be vertical?
A: It is not necessary.
3. Why are there anti-dumping measures for gas cylinders?
Answer: Pouring the cylinder can cause the valve to dislodge, releasing the gas stored inside. The powerful force of the escaping gas can cause the cylinder to move quickly forward or rotate on the ground, potentially injuring someone nearby.
Furthermore, if the gas is combustible, it could cause an explosion, which could have even more serious consequences.
4. Why should oxygen and acetylene cylinders be stored separately?
Acetylene is highly flammable, while oxygen supports combustion.
If acetylene leaks, it can mix with air and cause a violent explosion if it comes into contact with sparks or open flames. Such an explosion may cause damage to the oxygen cylinder and result in oxygen leakage.
The combustion supporting property of oxygen can exacerbate the intensity of the explosion beyond control. Therefore, it is crucial to keep acetylene and oxygen separate and avoid putting them together.
5. Why can't the bottle be exposed to sunlight?
The temperature of the acetylene cylinder should not exceed 40℃, and the boiling point of acetone is 58℃. As the temperature increases, the rate of acetone volatilization also increases. This can cause the acetylene to separate, leading to a sharp increase in cylinder pressure.
6. Why should there be residual pressure in acetylene cylinders and oxygen cylinders?
To ensure safe use, a small amount of pressure remains in the acetylene cylinder, which makes the pressure inside the cylinder greater than the pressure outside. This helps prevent other gases from entering. Because acetylene's explosion limit is low, it can explode if mixed with some air and exposed to a certain temperature.
Therefore, it is crucial to have a pressure reducing valve installed on the cylinder exhaust port to prevent air from mixing with acetylene. Otherwise, there may be a risk of explosion during the next use.
The use of a pressure reducing valve is also essential to keep the air pressure inside the cylinder greater than that of the air outside and to prevent air from returning to the acetylene cylinder. In the case of an oxygen cylinder, it must retain a residual pressure of at least 0.098 ~ 0.196 MPa gauge pressure.
For acetylene cylinders, a gauge pressure residual pressure of 49Kpa ~ 98KPa in winter and 196KPa in summer must be maintained to ensure safety.
7. Why can't oxygen cylinders, especially the mouth of the bottle, be contaminated or come into contact with grease?
Oil, especially unsaturated and acidic fat, has a tendency to vaporize and release heat, which is why cheesecloth heads and oil cloths can self-ignite due to oxidation in the air, with the heat unable to dissipate. Once the auto-ignition point is reached, auto-ignition can occur.
However, the oil vaporizes slowly in the air and the heat generated dissipates quickly, making it generally difficult to accumulate heat and ignite spontaneously.
When oil and fat come into contact with pure oxygen, their gasification speed accelerates significantly, releasing a lot of heat that causes a rapid increase in temperature and combustion. Pure oxygen has strong oxidizing properties that promote the violent combustion of fuels.
If the mouth of the oxygen cylinder is contaminated with grease, the grease will be quickly oxidized when oxygen is sprayed, and the heat generated by friction between the high-pressure air flow and the cylinder mouth will further accelerate the oxidation reaction. This can cause the grease in the oxygen cylinder or pressure reducing valve to ignite and even explode.
Therefore, it is strictly prohibited for the oxygen cylinder, especially the cylinder mouth and accessories in contact with oxygen, to come into contact with grease.
8. Why do gas cylinders use caps?
Most steel cylinder valves are made of copper alloy, which is relatively brittle. Although some are made of steel, they have a smaller frame than the cylinder body and are rotated in the cylinder body to form a right angle between the neck and the cylinder valve gasket. These areas are vulnerable and prominent points of the cylinder body and are most susceptible to mechanical damage or external impacts during handling, storage and use.
If the cylinder falls, rolls or is hit by other hard objects due to careless damage, the gasket of the cylinder valve and neck will be easily broken, leading to serious consequences. If the valve on the oxygen bottle is broken, the high pressure gas (150 kg/cm2) in the bottle will be ejected, causing the cylinder to move in the opposite direction and potentially damaging machinery, equipment and buildings, or even causing casualties. .
If the valve on the acetylene cylinder is broken, flammable gas rushes out, forming an explosive gas mixture with air, which can explode when encountering an open fire. Furthermore, if the cylinder contains combustible gas, static electricity generated by the high-speed jet or other ignition sources may cause combustion and explosion.
Furthermore, when the bottle valve is exposed, it is susceptible to the intrusion of dust or greasy substances during handling and storage, creating a potential hazard. Wearing a safety helmet can prevent contamination and entry of dust or grease.
To eliminate these hazards, the cylinder manufacturing unit must equip the cylinder with a safety helmet before leaving the factory. When using gas, unscrew the safety helmet and place it in a fixed location. After use, replace and tighten the bottle cap immediately and avoid throwing it away. Never forget to wear a safety helmet when handling.
9. Why should acetylene cylinders not collide?
The collision can result in the breakdown of the activated carbon, leading to increased expansion space. This, in turn, causes acetylene gas to build up under high pressure, creating a risk of explosion. Furthermore, as the temperature increases, gaseous acetylene can polymerize, resulting in an explosion.
10. Why is it necessary to load and unload cylinders carefully and is it prohibited to throw, roll or collide?
Answer: Due to the serious collision or impact on the gas cylinder, an explosion accident will occur and the consequences will be very serious.
11. Why can't oxygen cylinders be lifted?
Oxygen cylinders are high-pressure containers that can easily explode if dropped carelessly.
When transporting multiple oxygen cylinders, a special container designed for single use is recommended. This container is suitable for loading and unloading cylinders safely.
12. Why do acetylene cylinders explode?
The explosion of an acetylene cylinder is mainly caused by a rapid increase in temperature and pressure and the decomposition of acetylene.
The following are the characteristics of the decomposition of acetylene:
If the temperature of the bottle wall increases (starting at the top of the bottle) or if an abnormally odorous gas with smoke escapes from the open valve of the bottle after tempering, this indicates that the acetylene has begun to decompose. If the acetylene cylinder is exposed directly to flame or radiant heat, there is a risk of acetylene decomposition at any time.
Reasons for the decomposition of acetylene:
(1) Welding tempering;
(2) External heating (flaming substances are close to the acetylene cylinder and tools such as welding or cutting guns that have not been extinguished are left hanging from the cylinder);
(3) The acetylene near the cylinder valve or pressure reducer is on fire;
(4) Severe shock or vibration.
Precautions:
- Install the flame arrester.
- It is strictly prohibited to expose the bottle to sunlight, heat it or place it near a heat source.
- Do not hang any tool, such as a welding or cutting gun, that is not unlit on the acetylene cylinder.
- Handle the cylinder with care to avoid strong impacts or vibrations.
13. Why can't oxygen tape and acetylene hose be mixed?
Oxygen tubes are designed for high pressure applications while acetylene tubes are designed for low pressure use.
Additionally, when using acetylene tubes, slight flashbacks may occasionally occur and carbon deposits may accumulate in the tubes. If these deposits mix with oxygen, they could cause an explosion.
14. Why can't cylinders be mixed?
Answer: If the cylinder is filled with other gases, a serious explosion will occur, with very serious consequences.
15. Why must the lower part of the oxygen cylinder be insulated when used in the same location as electrical welding?
Answer: To prevent electrification of gas cylinders.
When working with an electric welder (assuming this is the context), it is important to fill the bottom of the oxygen cylinder with insulating materials to prevent it from becoming electrified.
Furthermore, any metallic equipment, such as piping, that comes into contact with gas cylinders must have good grounding devices to prevent accidents caused by static electricity, such as burns or explosions.
16. Why can't acetylene cylinders be used in insulators?
The ignition energy required to ignite acetylene is only 0.019 mJ. This means that even a small electrostatic discharge, typically several mJ, can cause the acetylene to ignite or even detonate.
When acetylene flows or leaks through a gas transmission pipe, it generates static electricity. Any form of electrostatic discharge can cause ignition.
Once ignited, acetylene combustion and explosion can occur without the need for oxygen, making explosion highly likely.
To avoid explosions, it is advisable to directly ground the acetylene cylinder. By doing this, the cylinder will not accumulate static electricity, significantly reducing the risk of explosion.
17. Why should the copper content of the alloy be less than 70% when copper alloy apparatus is used for acetylene cylinders?
Prolonged exposure of acetylene to copper and silver can lead to the formation of explosive compounds, namely copper acetylide and silver acetylide. These compounds can cause an explosion under extreme vibration or when exposed to temperatures between 110-120℃.
