2.6 COMMISSIONING The first year of operation is crucial, because when the pipe is put into service, all debris is pushed downstream, and contaminates the valves along it’s travels. With time, the pipe gets cleaner and initial problems disappear. Strainers or filters should be installed upstream of all soft seated valves. The same recommendations regarding grease injection for flushing (see 2.4) apply for commissioning. By refilling the grease channels multiple times, the dirt is gradually pushed out of the seats. Provided that the grease is properly chosen (see 2.4), it will not damage the valve, and to a certain extent will shield the seats from contamination. Regular cycling is also important, for two reasons: to prevent the seats from getting stuck, and to distribute fresh lubricant over the seating surfaces of the ball and seats. Once the seat is greased, it is a good idea to pump fresh grease into the seat to expel any debris laden grease (see 2.4.3) before cycling the valve to avoid damage to soft seat inserts. Many operators prefer not to grease seats even during commissioning as the grease can attract debris which can damage the seats if the valve is then turned. Also grease channels can become blocked if grease hardens. However, if the service is dirty the seats will damage either way hence many users find regular greasing delays the damage. Should you need to apply grease to seats, ensure you then inject fresh grease to dispel any grease which may have attracted contaminants and then partially stroke the valve multiple times to remove as much grease as possible from the seats. After commissioning, once you believe the service is clean you can inject a suitable grease line flushing agent and then partially stroke the valve again. You should consult a valve maintenance specialist as different service, media, pressures, temperatures, etc., can require totally different practises. APV recommends the following programme for start up: - 1. For the first year, inject a small amount of grease into the seats before turning the valve, every time. 2. Cycle the valves periodically as follows: • For the first month, every week. • For the second month, every two weeks. • For the third month, every month, for at least 6 months. • Then every three months. Depending on the type of seat inserts and type of particulates encountered in the media, after commissioning it is best to only use the seat lubrication nipples for emergency use as it is possible that grease on the seats will actually attract debris which can then damage the seats during closing or opening. Nylon and Devlon are hard and resistant to scratching, PEEK® is even harder. Teflon® (PTFE) is softer and scratches easier yet it can have more resilience and ‘memory’ in terms of resistance to permanent indentations. Also note, PEEK seated valves have a higher operating torque. Teflon has the lowest operating torque, however it has more ‘memory’ and if left closed for a long period of time the Australian Pipeline Valve - Installation, Operation and Maintenance Manual 10 SIDE ENTRY 2P TRUNNION BALL VALVES API6D STANDARD - FS9000 SERIES Note Remember that ball valves in natural gas service are like the human body; they need ‘exercise’. Keep moving them and lubricating them, and you will have fewer problems. Do not let them have a sedentary life.