Vent Manifold


Spreadsheet template that calculates pressure profile in vent manifold
or flare system | $29  BUY NOW

This is important because relief devices are designed to work with certain developed back pressure. If the pressure drop through the manifold exceeds design parameters, the relief valves must be de-rated. VentManifold calculates the pressure profile through a manifold of relief valve discharges. It is used for evaluating the design and safety of a flare system or manifolded relief valve system.

Click on any of the graphics below to see a larger version.

Both SI and English (American) units are supported, and you can toggle back-and-forth between them.

Up to 15 sources can be combined together. Only two sources or pipe segments may join at any one node. After you construct a sketch of your system and name the "nodes" (the points where two pipes combine to form a third), the manifold is entered very simply. Each segment of pipe within the network is described with its "upstream" node, "downstream" node, equivalent length of pipe, and pipe diameter.

Each source is specified in terms of relieving rate (mass of vapor per hour), temperature, molecular weight, and viscosity. You also enter the maximum permissible back pressure at the relieving source. VentManifold does the calculations to estimate physical properties of combined vent streams.

Detailed calculations are performed to compute the pressure at each node in the system. If any errors are present, such as incomplete definition of the manifold, excessive pressure (compared with allowable back pressure), excessive velocity (higher than sonic velocity which is physically impossible), etc., then appropriate error messages are generated on the screen and on the printed output.

Speaking of output, PipeManifold assembles the input data and results on a professional-looking "Datasheet". There's a space to insert your company logo. Print the report and put it in your project file or notebook for a permanent record.


Read a detailed article with a description of how VentManifold is designed, and specific recommendations for engineering a manifold system.