Gases and pressurised devices

A gas is defined in the Swedish Work Environment Authority’s regulation as a substance in a gaseous state, a substance in a liquid state (liquefied gas) with a vapour pressure above 3 bar (0.3 MPa, absolute pressure) at + 50 °C and carbon dioxide in a solid state.

The aggregation state of a substance (solid, liquid or gas) is determined by the environment in which the substance is located. When changes in pressure and temperature occur, the substance can transition from one state to another. Gas is often handled at high pressures, which places high demands on the material. Pressurised devices may not be used at a higher or lower pressure and temperature than recommended by the manufacturer or an accredited control body.

If the gas container becomes damaged for any reason, people close by may be harmed by exposure to the gas, by suffocation, fire or explosion, by the pressure wave from the gas release or by propelled materials. If the gas also spreads over a larger area, it is mainly the chemical properties of the gas that can cause injury and harm. The dispersion of the gas depends on its physical properties, such as density relative to air and temperature and external factors such as wind direction and wind speed. Heavy and cold gases spread along the ground, while light gases move upwards.

In the event of an accident, block the area and warn staff and surroundings. Only people needed for rescue work may be in the risk area. Damaged bottles must be marked and the gas supplier must be informed before further handling / transport of the vessel.

In all activities where gas is handled, a risk assessment must be carried out. If the process, the equipment or other operating conditions change, a new risk assessment must be carried out. Based on the risk assessments, necessary measures must be taken to ensure adequate safety. There are various risks to consider when handling gas. These risks primarily regard inhalation, splashing on skin or eyes, suffocation and fire and explosion. The effects caused by the gas are dependent, e.g., on the type of gas, the concentration of exposure and the duration of exposure. If the risk of splashing or other contact cannot be excluded, appropriate personal protective equipment must be used.

In rooms where gas is handled, ventilation must be used that ensures that the oxygen concentration normally does not fall below 20% or rise above 22%. If the oxygen concentration is less than 18%, breathing apparatus must be used when working in the room.

At ORU, pressurised devices are used such as gas cylinders, fire extinguishers and autoclaves.

The employer must report any serious accidents or incidents to the Swedish Work Environment Authority as soon as possible. The employer is responsible for ensuring that accidents and incidents involving the use of pressurised devices are documented and investigated, and that necessary measures identified during the investigation are implemented.