Frequently asked questions.

Oxygen is a colorless, odorless gas that is poorly soluble in water and slightly heavier than air. At −183 °C, oxygen turns into a transparent bluish liquid with a density greater than that of water. Oxygen reacts with all elements except the noble gases, forming a class of compounds known as oxides.

As a strong oxidizer, oxygen accelerates combustion processes. When the concentration of oxygen in the air reaches 30% or more, intense combustion of almost all substances occurs. Oxygen supports the combustion of carbon, sulfur, magnesium, iron, hydrogen sulfide, and many metals and nonmetals. These properties make oxygen indispensable in various industrial sectors.

Liquid oxygen is obtained from atmospheric air using special equipment through the method of cryogenic rectification (fractional distillation of air). Atmospheric air is compressed to 5-7 atmospheres, then purified and dried. It is then cooled to extremely low temperatures until it liquefies. During distillation, oxygen is separated from other gases such as nitrogen and argon, and collected as a high-purity liquid. Liquid oxygen is widely used in medicine, aerospace, and industry.

Technical oxygen - is a form of oxygen produced for industrial use. It is usually of lower purity than medical oxygen, making it suitable for a variety of industrial processes. Thus, gaseous technical oxygen is used in areas such as welding, metal cutting, chemical processes, and steel production. It can be used both independently and in mixtures with other technical gases, such as acetylene, argon, and others.

When handling oxygen, strict safety precautions must be taken to avoid the risk of fire, explosion, or other dangerous situations. Here are the basic safety rules:

• Oxygen storage: Oxygen should be stored in specially designed containers in compliance with storage standards.
  Cylinders with gaseous technical oxygen can be stored both in special rooms and in the open air, in the latter case they must be protected from precipitation and sunlight. Storing oxygen and flammable gas cylinders in the same room is prohibited.
  Cylinders with shoes or a concave bottom must be stored in a vertical position. To prevent them from falling, cylinders must be installed in special nests, cages or fenced with a barrier.
  Cylinders that do not have shoes can be stored horizontally on wooden frames or racks, with devices that prevent them from rolling.
• Indoor use: Rooms where oxygen is used must be well ventilated. Do not use oxygen in closed or poorly ventilated rooms without prior preparation.
• No smoking: Smoking near oxygen cylinders or in areas where oxygen is used is strictly prohibited, as it may cause a fire.
• Use of equipment: Only use equipment designed for working with oxygen and ensure that it is in good working order. All devices and pipelines must be clean and free from contamination.
• Handling of cylinders: Oxygen cylinders must be stored in an upright position, in specially designated areas. Also, their falls and mechanical damage must be avoided.
• Use of oil is prohibited: Oil and greasy substances must not be used in areas where oxygen is used, as they can cause fire when in contact with oxygen.
• Transportation of oxygen: When transporting oxygen, specially designated vehicles should be used. Cylinders must be secured to prevent falling or damage. During transportation, avoid impacts, mechanical damage, and exposure to high temperatures. Oxygen should not be transported in confined, poorly ventilated spaces.

Cylinders intended for the storage and transportation of gaseous technical oxygen are prohibited from being used for the storage and transportation of other gases. It is also prohibited to perform any operations that may contaminate the inner surface of the cylinder and worsen the physical and chemical properties of the gas.

It is prohibited to modify the cylinder bodies using welding or mechanical tools, as this may lead to a violation of the integrity of the cylinder or the appearance of defects that worsen its technical characteristics.

When operating cylinders for gaseous technical oxygen, they must not be installed in areas where people pass, goods are moved, or vehicles pass.

It is prohibited to fully deplete the gas inside the cylinders. The residual pressure inside the cylinder must not be less than 0.05 MPa (0.5 kgf/cm²).

Valves in oxygen cylinders should be installed with sealing materials that are non-flammable in an oxygen environment.

It is important to remember that the oxygen pressure inside the cylinder changes with temperature variations during operation.

There are several criteria checked when exchanging a cylinder to ensure the safety of its subsequent filling:

• No damage:The cylinder must be free from dents, metal peeling, and gouges.
• Cleanliness:The cylinder must be clean, free of greasy marks and dirt.
• Residual pressure:The cylinder must have a residual pressure of at least 0.5 bar.
• Correct valve position:The cylinder valve must be in the correct position to ensure safe operation.
• Cylinder number and manufacture date:The cylinder must have a unique number and date of manufacture, which allows tracking its history.
• Expiration date:The cylinder must not be expired. It must be stamped with the month and year of the last inspection, as well as the date of the next inspection.
• Filling station stamp: The cylinder must have a filling station stamp confirming that the cylinder has been inspected and meets safety standards.

Carbon dioxide (CO₂) is a non-flammable, colorless, and odorless gas that is significantly heavier than air. It does not support combustion and is not toxic at low concentrations. When subjected to pressure above 5850 kPa and at room temperature, it transforms into a liquid, making storage and transport of the substance easier.

Carbon dioxide is widely used in various industries. It is commonly used in the food and beverage industry for carbonating drinks, in fire extinguishers as a fire suppressant, and in agriculture to enhance plant growth in greenhouses. CO₂ is also used in welding, medical applications, and as a refrigerant in cooling systems.

Argon (Ar) is an inert, neutral, colorless gas that is one of the most abundant in the Earth's atmosphere. It occurs in nature only as a component of atmospheric air. While argon is not suitable for sustaining life, it is indispensable in certain technological processes due to its high chemical inertness and relative ease of extraction.

Argon is produced as a byproduct during the extraction of nitrogen and oxygen from atmospheric air. The simplest method of production involves deep cooling and rectification, followed by purification from impurities. Argon can also be obtained during ammonia production. For further purification, technologies such as hydroding with a platinum catalyst or adsorption methods using molecular sieves or activated carbon are employed.

Due to its chemical inertness, argon is used in a variety of industries: in the welding process (particularly for TIG welding) and to protect metals from oxidation at high temperatures; as an atmosphere for growing crystals and in material processing; as an inert gas in chemical reactions and in analytical methods such as gas chromatography; in the production of certain types of lamps, such as neon and other gas-discharge lamps; in some medical lasers, as well as in cryosurgery for freezing and destroying tissue; in food packaging to prevent oxidation and extend shelf life.

Oxygen, argon and carbon dioxide cylinders have information stamped on its body near the neck (cylinder passport), which includes the following data:

• Trademark of the manufacturing company.
• Cylinder serial number.
• Actual weight of the empty cylinder with an accuracy of 0.2 kg.
• Date (month, year) of manufacture and the next technical inspection. If the cylinder has undergone several technical inspections, information about them is knocked out one under the other, or the year of the next technical inspection, certified by a stamp, is added to the existing record.
• Working pressure ("Р") (kg/cm2, bar, MPa).
• Test hydraulic pressure ("П") (kg/cm2, bar, MPa).
• Cylinder capacity with an accuracy of 0.3 l.
• Stamp of the organization that conducted the technical inspection.
• Stamp of the manufacturing company.

Cylinder inspection is a comprehensive check of gas cylinders for strength, tightness and compliance with safety requirements, which is carried out once every 5 year, and include the following:

• External inspection – checking the body for damage, rust and defects.
• Outer surface cleaning – removing dirt and old markings.
• Air release and valve removal – for safe access inside.
• Internal inspection – checking the condition of the inner surface for corrosion and mechanical damage.
• Weight and capacity verification – measuring the mass of the cylinder and its actual volume.
• Hydrotesting – filling with water and testing for strength under increased pressure.
• Internal cavity drying – removing moisture to prevent corrosion.
• Valve reinstallation and checking the tightness of the connection – installing a new or tested valve.
• Cylinder passport marking – application of information about the date of the last and the next inspection.