Is there a manual for the unit in the workshop office? That would show what the design is and what regulation equipment is required for it. It should be regularly inspected by a competent (i.e. gas safety trained) person who could help you.

In INDG261 Rev 2 (http://www.hse.gov.uk/pubns/indg261.htm), under 'Know The Operating Conditions', the following is bullet pointed -
" Know the process conditions, such as the pressures and temperatures". So, a question to ask may be 'how does the operator know whether the correct process pressure is being applied and how is it regulated?'

I would also check with your gas safety trainer.