Background

Hydraulic systems in general are excluded under Schedule 2.

Hydraulic systems generally include items which are defined in Schedule 1 as pressure equipment (for example pressure piping).

A question therefore arises as to whether items which are in themselves pressure equipment as defined in Schedule 1 are subject to the Regulations, despite being part of a hydraulic system which is excluded through Schedule 2.

The intention of the exclusion in Schedule 2 of hydraulic systems was to remove from jurisdiction of the Regulations such systems as are commonly found performing the control and actuation functions of industrial, construction and agricultural machinery.

It is recognised that there may be cases where the scale and hazard of some untypical hydraulic systems may require treatment as pressure equipment.

Clarification

Only hydraulic systems whose function is control and/or actuation are the subject of this clarification (i.e. it does not apply where the primary purpose of the system is the conveyance of the fluid).

In order to differentiate between the majority of Schedule 2 excluded hydraulic systems, which need not be covered by the Regulations (though possibly technically qualifying as pressure equipment), and those parts of exceptional systems which may need full compliance, the following criteria will be applied:

1. If any part of the hydraulic system contains only oil or water, it is excluded.
2. If any part of the hydraulic system contains fluid(s) other than oil or water, and its hazard level is not greater than E when assessed in accordance with AS 4343-1999, it is excluded.
3. Otherwise the part of the hydraulic system is treated as pressure equipment subject to the Regulations.