Cylinders containing oxygen or acetylene generally should not be placed in confined spaces due to the risk of fire, explosion, and lack of ventilation. However, under certain limited circumstances and with strict safety measures, they may be temporarily placed in confined spaces such as workrooms, but only if permitted by regulations and with precautions like having appropriate ventilation, safety barriers, and keeping quantities minimal. Key points from safety regulations and guidance:
- Cylinders containing oxygen or acetylene must not be taken into confined spaces or excavations except for self-contained breathing air cylinders in some cases.
- Oxygen and fuel gas cylinders must be separated by at least 20 feet or a noncombustible barrier when stored.
- When the scope for external storage is restricted, a spare cylinder of acetylene and oxygen may be kept inside a workroom, but larger quantities require a fire-resistant store with explosion venting to the outside.
- Welding or cutting operations in confined spaces should have the gas cylinders left outside whenever possible.
- Regulations such as OSHA and HSE emphasize not placing oxygen or acetylene cylinders in confined spaces unless specific tunnel or enclosed space exceptions apply with corresponding safety measures.
- Acetylene cylinders should never be stored in unventilated rooms, underground rooms, or areas accessible to the public, emphasizing the need for ventilation when cylinders are indoors.
In summary, cylinders with oxygen or acetylene are generally not allowed in confined spaces except under controlled conditions such as limited internal storage with ventilation, fire-resistant barriers, and minimal quantities, or specific regulated exceptions in tunnel or enclosed spaces with additional safety standards applied.
