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!

Maximum Relieving Capacity of Free Air (cfm)
Valve
Diameter (inches)
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

Related Documents

Sponsored Links

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 the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!

Translate
About the Engineering ToolBox!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Citation

This page can be cited as

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

Modify access date.

. .

close

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!

Scientific Online Calculator

Scientific Calculator

3 30

Sponsored Links
.