Zero emissions reciprocating pump

A sealing system for a pump having a plunger includes a housing having an internal chamber adapted to receive a portion of the plunger. Primary and secondary seals are located within the internal chamber and adapted to sealingly engage the plunger. The primary seal communicates with the fluid being pumped. A barrier fluid chamber contains a barrier fluid in contact with the primary seal and the secondary seal. A pressure referencing device has an inlet port in communication with the pumped fluid and an outlet port providing fluid at a pressure magnitude equal to a peak pressure of the pumped fluid. A pressurizing device is in communication with the fluid at the peak pressure and the barrier fluid to maintain the barrier fluid pressure at a magnitude greater than the peak pressure of the pumped fluid such that the pumped fluid is restricted from leaking past the primary seal.