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The ZEECO® Spring Actuated Non-Reclosing Pressure Relief Device - for accurate, safe pressure control. 


Zeeco’s Spring Actuated Non-Reclosing Pilot-Operated (SA-NRPO) Pressure Relief Device is designedto relieve gas pressure in flare systems. While the system is most commonly found in ground flare systems, any flare staging application requiring a fail-safe bypass device can utilize the SA-NRPO Pressure Relief Device. In comparison to other bypass devices, Zeeco’s SA-NRPO Pressure Relief Device eliminates the use of pins, has a very quick and simple reset procedure, and can operate at a relief set pressure as low as 0.25 psig. The SA-NRPO Pressure Relief Device can save you time, money, and materials. 


 A tightly-controlled manufacturing process achieves a precise pressure setting - time after time. 

The device materials are purchased from certified suppliers with decades of industry experience. Each device consists of a minimal number of machined parts manufactured with tight tolerances. The high level of quality control used in the manufacture of the base materials as well as the machining process creates a consistent and repeatable performance of the pressure relief device. 


 Resetting the device is a one person job. 

Local and remote failure indication switches display the status of the device’s position. Following an overpressure event, re-setting the device can easily be done by a single operator in just a few minutes. An easily accessible design coupled with proven technology allows for reseating the device from outside the gas stream and with little downtime using only the push of a button. Opening the process line is not required. 


Design Features Butterfly Valve w_spring pressure sensor

  • Design components that have been time tested for decades 
  • Actuator sized to allow available air supply pressure to hold device in closed position 
  • Predictable and repeatable opening rates 
  • Easily hold tolerance of +/- 2 psig or +/- 5% for set pressures over 40 psig 
  • Positive shut off until set point is reached 
  • Re-seat the device in a matter of seconds with the push of a button 
  • No fugitive emissions 
  • In overpressure event, there are no pieces to separate in the device. No fragments flow to the downstream piping – a common issue with rupture discs. 



  • Constructed to ASME sections VIII and XIII, ASME UD stamp available 
  • Standard body materials are available for operating temperature from -196ºC to 1000ºC 
  • Capacity and Flow Resistance Certification as per Section 9 of ASME Section XIII 
  • Quality documentation is available for all aspects of fabrication and testing 
  • Standard documentation includes Device Certification Sheet, Performance Test Record, Hydro Test Record, and Leak Test Record 
  • Standard sizes range from 6” to 96” with pressures from 0.25 to 500 psig
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