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Swagelok® products and services are delivered locally through a network of more than 200 authorized sales and service centers that support customers in 70 countries on six continents.
Safe Product Selection:
The complete catalog contents must be reviewed to ensure that the system designer and user make a safe product selection. When selecting products, the total system design must be considered to ensure safe, trouble-free performance. Function, material compatibility, adequate ratings, proper installation, operation, and maintenance are the responsibilities of the system designer and user.
Do not mix or interchange valve components with those of other manufacturers.
Home > Products > Valves > Relief


High Pressure Relief Valves
Proportional Relief Valves High Pressure
Low Pressure Relief Valves
Proportional Relief Valves Low Pressure
Relief Valves Spare Parts
Spare Parts and Accessories
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Relief Valves and Proportional Relief Valves

Swagelok offers proportional relief valves for general-industry applications and relief valves for use in the sanitary industries. We offer both high pressure relief valves and low pressure relief valves.



Proportional Relief Valves R Series
  • Spring adjusts to provide desired set pressure
  • Cap provides easy external set pressure adjustment
  • Label identifies set pressure range
  • Lock nut maintains cap position, ensuring set pressure adjustment
  • Lock wire capability secures cap to maintain set pressure adjustment
  • Quad seal eliminates leakage around the stem during relief mode
  • O-ring or bonded disc provide elastomer-to-metal seal for positive shutoff at seat

R3A Series and R4 Series High-Pressure Relief Valves

  • Service up to 6000 psig (413 bar)
  • Multiple springs for a selection of set pressure ranges.

RL3 and RL4 Low-Pressure Relief Valves

  • Service up to 300 psig (20.6 bar)
  • One spring for the full set pressure range


R series relief valves are proportional relief valves that open gradually as the pressure increases. Consequently, they do not have a capacity rating at a given pressure rise (accumulation), and they are not certified to ASME or any other codes.

Some system applications require relief valves to meet specific safety codes. The system designer and user must determine when such codes apply and whether these relief valves conform to them.


Every R series proportional relief valve is tested for set and resealing performance.

Cleaning and Packaging

All Swagelok R series relief valves are cleaned and packaged in accordance with Swagelok Standard Cleaning and Packaging (SC-10).


Relief Valve Cutaway Manual Overide Handles

A manual override handle opens the valve without changing the set pressure. Manual override handles are available factory installed or in kits for field assembly.

Special Cleaning and Packaging

Swagelok Special Cleaning and Packaging (SC-11) to ensure compliance with product cleanliness requirements stated in ASTM G93 Level C.

Spring Kits

Replacement spring kits are available for all models.

Seal Materials

Fluorocarbon FKM is standard. Buna N, ethylene propylene, and neoprene seals are available factory-installed or in replacement seal kits for field assembly.

Relief Valves for Sanitary Applications

Air Relief
Air Relief Valve


  • Remove air from line or tank with minimal product loss
  • 316L SS construction
  • Polypropylene ball
  • Standard Buna body gasket; other gasket materials available
  • 1 1/2 to 4 in. Kwik-Clamp end connections

Sanitary Relief Valves


  • 316L SS construction
  • 3/4 to 3 in. Kwik-Clamp end connections
  • 1 to 3 in. Acme threaded end connections
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