5.3 Flammable gases

Handling gas cylinders in the laboratory

• Gas cylinders containing flammable gases must not be stored in the laboratory. However, there is an exception for gas cylinders with a maximum capacity of 10 liters, which can be used temporarily during a specific day but never to be left over night or weekends.
• Pay attention to the EX-zone: Ensure that no electrical devices are present in the EX-zone, except for EX-classified equipment.
• Storage: When not in use, cylinders must be kept in a designated gas cabinet. These cabinets should be clearly marked with symbols denoting the EX-zone, flammability, and gas cylinders.
• Acetylene gas cylinders: For acetylene gas cylinders, regulators should be installed to prevent backflow in pipes or within the cylinder. The pressure in the regulator should not exceed 1.5 bar. Regular selftesting, including leak testing, should be conducted twice per year and documented. Additionally, safeguards should be checked by a qualified person every other year and documented. Fireproof gloves should be readily available near the acetylene gas cylinder in case of fire. Acetylene gas has a garlic-like odor.
• Hydrogen gas: Hydrogen gas is highly flammable. It is 15 times lighter than air, odorless, and burns with a clear flame. The main risks when working with hydrogen gas include leakage, fire, and explosion.

Pictogram		What shall be marked
		Laboratories where compressed gas is used and stored, shall display this sign on the door.
		Cabinets containing flammable gases shall be marked with these signs/pictograms.