What is difference between an inspection and a test?
PI or PIAT?
Periodic Inspection (PI) is commonly referred to as a visual inspection
During a PI the cylinder is emptied, the boot is removed, the valve is removed, the outside of the cylinder is inspected to ensure it is safe to use, the inside is inspected for rust and other contaminants and the threads of the cylinder and valve are checked with certified gauges to ensure they are still adequate
Periodic Inspection and Test (PIAT) commonly referred to as a hydro
During a PIAT the first thing to be done is the Periodic Inspection the same as above.
Once this is done the cylinder if filled with water and first of pressurised to it's working pressure i.e. 232 or 300 bar typically and then pressurised to it's test pressure i.e. 348 or 450 bar, if the cylinder passes this then is has passed it's PIAT
The cylinder is then dried, re-assembled, stamped and labelled
For both a PI or PIAT your valve will be inspected and serviced
The threads on the valve will be inspected and tested with a gauge to ensure they are serviceable and the valve will be disassembled, cleaned and reassembled