There can be confusion over the size of a compressed gas cylinder. Sometimes the rating is its physical volume (ie. how much water it would hold if filled), and sometimes it is given by the volume of compressed gas it can hold. Typical cylinders of nitrogen are small (2-liter) and hold ~400 liters of gas under pressure. These can be referred to as either 2-liter or 400-liter cylinders!
Gas pressures are measured in Bar (bar) or Megapascal (MPa) or psi (pounds/square inch): 1 bar = 0.1 MPa = 14 psi
Ensuring a Cylinder is Full
When using a cylinder of compressed gas for a peaceful death, it is important to establish that there is sufficient gas available. The easiest way of ensuring the gas cylinder is full, is to measure the pressure. This is particularly important for cylinders that have been kept in storage for long periods.
Max Dog Brewing (http://www.maxdogbrewing.com) sell a regulator that will show the gas pressure on the gauge. To measure the pressure, attach the regulator to the cylinder, set the regulator flow rate to 0 liters/min, and open the cylinder. This will show the pressure on the gauge.
To obtain the optimal steady gas flow from a cylinder of compressed gas a regulator is always needed. Regulators break down the high gas pressure in the cylinder to the much lower pressure needed to gently deliver the gas to the Exit bag. A flow