Pressure Safety Valve (PSV) Material Selection

Specify the Pressure Safety Valve (PSV) material could be simple and might be difficult for some situation. It becomes simple because the API 526 only state the requirement of the body, bonnet, and spring material. Nevertheless, the API 526 standard leave the internal part material to the manufacturer’s standards. If the project requirement or Company standard require the material of the PSV shall follow the API 526, then the material selection of the PSV is simple. Just specify the body/bonnet material of the PSV in accordance with the related PIPING globe valves and leave the other parts to manufacturer’s standard. It means, we need to know the piping class of our PSV, see the globe valve code number for the specified piping class, and then open the manual valve datasheet of the globe valve. We will then just simply state the disc, guide, nozzle, etc, to become manufacturer’s standards.

Valves Material Comparison

During vendor bids evaluation of the valve package, usually we will face the problem of material review from the Vendor offer. Let’s say we require a valve with A182 F53 Duplex stainless steel trim material, but the Vendor offer different material such as A182 F51 Duplex stainless steel. To accept or not this Vendor offer will be a problematic issue for an instrument engineer. In this case, just contact the material engineer and ask them whether vendor offer is acceptable or not.

However, as a general guideline, the following table could be used just to compare the superiority of one material to other material. Use the table with below notes as a general guideline.

End Connection of Control Valves

The control valve end connection may have flange connection, threaded, or even welded end. Flange connection is the most common control valve end connection in the oil & gas application. Other connection such as threaded or welded end is only used in particular application.