Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Safety Relief Valves - Capacities vs. Pressure

Maximum safety valve free air relief capacity.

Sponsored Links

Safety valves and maximum relief free air capacity:

For full table - rotate the screen!

Safety Relief Valves - Capacities vs. Pressure
Valve
Diameter
(inches)		Max. Relieving Capacity of Free Air (cfm)
Gauge Pressure (psi)
5010015020025030035040050060080010001200160020002400
1/4 12 20 27 33 38 43 48 53 61 70 84 97 109 128 147 160
3/8 17 27 36 44 51 58 65 72 83 95 115 133 149 176 197 215
1/2 20 32 42 51 59 67 74 111 129 147 177 205 230 270 304 330
3/4 37 59 78 96 112 127 141 176 224 232 242 346 386 423 474 518
1 58 94 124 152 178 202 224 248 286 324 390 450 500 586
1 1/4 84 135 180 221 259 293 325 352 400 443 509
1 1/2 114 186 248 302 354 400 444 478 528 568 634
2 189 306 410 501 592 668 741
2 1/2 282 457 613 750 880 998 1114
3 393 638 856 1050 1230 1398 1557
  • 1 inch = 25.4 mm

The relief capacity for a safety valve depends on

  • the relief discharge area
  • the compressibility factor of the actual gas
  • the temperature of the gas
  • the geometry of the safety valve

A safety relief valve must be capable of relieving the capacity of the connected compressor(s) at operating pressure. Note that the relief pressure can not be set higher than the maximum rated working pressure of any equipment in the system. If the operating pressure is right below the relief pressure of the valve the valve may start leaking.

A "rule of thumb" is to set the relief pressure 10% above the working pressure of the system.

Sponsored Links

Related Topics

  • Control Valves and Equipment

    Sizing and dimensions of control valves & equipment in steam and condensate systems.

  • Gases and Compressed Air

    Air, LNG, LPG and other common gas properties, pipeline capacities, sizing of relief valves.

  • Heating

    Heating systems - capacity and design of boilers, pipelines, heat exchangers, expansion systems and more.

Related Documents

Sponsored Links

Search

Search is the most efficient way to navigate the Engineering ToolBox.

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

Translate this Page

Translate this page to Your Own Language .

About the Engineering ToolBox!

Privacy Policy

We don't collect information from our users. More about

Citation

This page can be cited as

  • The Engineering ToolBox (2003). Safety Relief Valves - Capacities vs. Pressure. [online] Available at: https://www.engineeringtoolbox.com/safety-valves-capacity-d_473.html [Accessed Day Month Year].

Modify the access date according your visit.

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter

















































12.8.9

Sponsored Links
.