Flexible joint for Centrifugal Pump

Greetings,

We are using a centrifugal closed type Pump of model CPK EGY for pumping crude oil at an operating temperatur of less than 50 deg celsius(2" line). I need to understand whether the suction and the dischareg end of the pump needs to be isolated from the equipment and pipe by flexible joints. the system is also at a temp of 50 deg celcius(no thermal expansion). the piping system is properly supported and does not have stress load on the pump. There is no vibration felt from the pump. is it required to have flexible joint if yes is there a standrad for selection guide.