Pressure Safety Valves Calculator - Fire Case Gas Filled Vessel

AI Thread Summary
The discussion focuses on understanding a pressure safety valve (PSV) sizing calculator for gas-filled vessels in fire scenarios. The calculator is based on API 520 standards, which should be verified before practical application. The user is specifically interested in sizing relief valves for an anaerobic digester operating at low pressures, noting that many existing standards only address pressures above half a bar. Recommendations include adhering to the Pressure Equipment Directive (PED) for European installations and consulting API RP 521 for fire heat input calculations. Overall, accurate sizing and compliance with relevant standards are emphasized for safety and regulatory adherence.
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This worksheet determines the required pressure relief valve orifice area for a gas filled pressure vessel that is on fire.

These calculations are usually based on API 520. I would verify the calculator before you use it for any real relief valve sizing.
 
Thanks for your reply

Im looking at an anaerobic digester with an operating pressure of between 20 and 30mbar. Usually relief valves will be set to release at around 35mbar.

Standards I've found are

ISO 4126 (harmonized with European Union directives) [5]
EN 764-7 (former CEN standard, harmonized with European Union directives, replaced with EN ISO 4126-1)
AD Merkblatt (German)
PED 97/23/EC (Pressure Equipment Directive - European Union)

Most only cover above half bar do you or does anyone know if there are any other regs to consider?

If not is there a simple calculation for sizing relief valves?

ZEN
 
From your standards it looks like this is a European installation.

Assuming this, the PED will apply. You will need to get your relief valve CE Marked and the CE Declaration of Conformity should list the highest applicable PED category.

I would suggest following API RP 521 to determine the heat input from fire and API 520 to calculate the relief valve size. You should be able to download or order these standards - they will have all the equations.
 
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