Acetylene mixed with air is explosive within 2.2% to 85% by volume. Avoid releasing acetylene into the air and ensure good ventilation where acetylene cylinders are stored or used.

When acetylene cylinders are transported horizontally and placed vertically again after transport, a period of at least 24 hours before using the cylinders for gas extraction must be obeyed. This to ensure that the acetone inside the cylinder redistributes in a correct way. When cylinders are used too quickly after placing them vertical again the following can happen:

* When opening the top valve, large amounts of acetone can come out. The customer might interpret this as water/oil because acetone feels slippery on the skin. Opening the top valve without a fitted regulator should not be standard practice as this can create a fire hazard.

* When a regulator is fitted with twin hose and torch, the lighted flame will be very unstable due to the presence of acetone droplets in the gas. This is often referred to as “spitting”.

Solution is to let the cylinder rest for at least 24 hours (depending on temperature; colder environment might require longer time).

Tare "A" weight of acetylene cylinders includes cylinder shell, neckring, valve, porous mass and acetone. For acetylene the following is valid:
1 nm3 = 1.095 kg
1 kg = 0.91 nm3
1 bar = 14.5 psi
1 nm3 = 35.3 ft3
1 kg = 2.2 lbs