Air Fittings – Safety Check Valves


Check Valve in Open Position

Check Valve in Closed Position


  • Conforms to OSHA regulation 1026.302 (b) (7) requiring a safety device at the source of the air supply and at branch air lines.
  • Applications include temporary plant/factory air, construction sites, shipyards or utilities.


  • High flow valve to provide optimum performance.
  • Controls excess air flow (SCFM) in only one direction.
  • Automatically senses change in air flow and shuts off the flow in the event of a surge in excess of valve flow rating thus preventing hose whip.
  • Not for use in applications where 100% of the available air is required, i.e. sand blast, pile driving rigs, expansion joint blow down pipes, etc.
  • Does not prevent backflow.


  • Solid brass body and valve.
  • Stianless steel spring and roll pin.
  • Maximum Pressure: 250 PSI
  • Maximum Temperature: 250°F


  • Safety check valves operate by using the pressure differential across the valve to operate the valve and spring assembly. The pressure differential is directly related to the flow of air (SCFM) through the valve.
  • When the pressure differential is within the operating limits – below the cutoff flow – of the unit, the force on the valve exerted by the spring is greater than that caused by the pressure differential (see “Open Position” graphic). The valve remains open and normal operation continues.
  • When the pressure differential is above the cutoff limit, the force on the valve exerted by the pressure differential is greater than the force exerted by the spring, and the valve closes (see “Closed Position” graphic).
  • After the repair is made, normal operation is automatically enabled when pressure across the valve equalizes through the bleeder hole.
  • The valve spring size can be specified by determining the air flow during normal operation and by estimating the air flow if a failure or rupture occurs.
    Part # NPT
    Hose ID
    Flow Rate
    (SCFM at
      Part # NPT
    Hose ID
    Flow Rate
    (SCFM at
    SCVL2 1/4″ 23-29 SCVL10 1-1/4″ 260-290
    SCVM3 3/8″ 39-47 SCVM10 300-340
    SCVS3 52-65 SCVS10 440-500
    SCVM4 1/2″ 70-78 SCVH10 570-630
    SCVS4 80-96 SCVL12 1-1/2″ 300-360
    SCVL6 3/4″ 72-88 SCVM12 470-530
    SCVM6 92-108 SCVS12 640-720
    SCVR6 112-128 SCVH12 750-830
    SCVJ6 132-148 SCVL16 2″ 510-590
    SCVS6 160-180 SCVM16 725-825
    SCVH6 180-200 SCVS16 900-1050
    SCVL8 1″ 165-195 SCVH16 1100-1200
    SCVM8 220-260 SCVL24 3″ 1200-1400
    SCVS8 280-320 SCVS24 2400-2700
    SCVH8 310-340 SCVH24 2850-3050
Category: SKU: SKUACEHOSE949