This appeared in Question 18.1 from the first paper of 2008.
Safety features of the gas cylinder:
- Safety outlet is fitted between the block and the cylinder neck which melts at low temperatures - allowing the escape of gas in case of a fire
- Pin index safety system
- Colour coded cylinders
- Nozzle colour
- Diameter index safety system
- Labelled yoke
- Knob texture
- Matching wall connectors
The cylinders, according to a reputable source, can withstand a pressure of 24,000 kPa, but normally rest at around 12,000-17,000 (that is the "green zone" on the gauge). The standard (mandatory) wall gas pressure is 415 kPa (about 4 atmospheres). For the gas which powers surgical tools, the pressure is 1400 kPa.