Pressure vessel testing is a requirement, in accordance to the South African Pressure Equipment Regulations (PER), to be carried out every 3 years on any vessel with an operating pressure of 50 kPa or higher. Other than being a prerequisite under law, consistent pressure testing is for the safety of workers and other people.. A pressure vessel can store compressed air at several times that of atmospheric pressure and can be hazardous if they are not maintained properly and tested regularly. By making sure that all air receivers or other vessels under pressure are operating according to SANS347, you are safeguarding a healthier and safer work environment.