Core Material Specifications


Good resistance to flexing and tearing. Very good rebound (memory) hot or cold.
Lubricating oil, gasoline, natural gas, refrigerants, aliphatic hydrocarbons.
−40°F to 200°F • 0—1000psi.

EPDM (Nordel)

Excellent rebound (memory). Excellent tear resistance. Good heat and cold resistance.
Hot or chilled water systems. NOT for use with gas or petroleum products.
−40°F to 300°F • 0—1000psi.

All core materials

  • Test readings should be taken as quickly as possible. Never leave probes inserted in plugs for extended periods as doing so will cause degradation/deformation of the core and may void the warranty. Always follow appropriate testing procedures and precautions.
  • All Fairfax cores and brass housings are backed by our limited 1 Year Warranty when used according to specifications. Compare to some competitor warranties that cover the brass for one year, but only protect the core for 30—45 days.

Testing Procedures


  • Always wear proper protective eyewear and gloves when performing test procedures.
  • Testing should be completed as quickly as is safe and reasonable. Never leave probes inserted for extended periods to prevent damage/deformation of valve core.
  • Always select appropriate gauge range for expected line pressure.
  • P/T Plugs should never be installed on the bottom side of a pipe where dirt or debris can collect an prevent proper re-seal.


  1. Examine probe for sharp burrs that could damage core material (sand or file as necessary). Apply a small amount of silicone lubricant.
  2. Slowly remove plug cap. (At any sign of escaping gas or liquid, retighten cap and determine if the plug has been damaged. Replace as necessary.)
  3. Insert gauge adapter probe or thermometer and record readings.
  4. Remove probe and replace cap immediately. Never leave probe in the plug any longer than necessary.

Plug will re-seal upon probe removal. Be aware that re-seal may take longer at temperatures below 45°F.