# Blocked Flow - Liquid Relief - Intergraph Smart Instrumentation - 13.1 - Reference - Hexagon PPM

## Integraph Smart Instrumentation Sizing Equations

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English (United States)
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Intergraph Smart Instrumentation
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Reference
Smart Instrumentation Version
13.1

Requiring ASME capacity certification

1. Calculate total back pressure:

2. Effective coefficient of discharge: Kd =0.65 (if Kd is not entered by user).

3. Determine correction factor for back pressure:

1. For conventional and Pilot operated valves, Kw =1.

2. For Bellows valve:

 Case Pb / Ps <0.16: Kw =1 Case 0.16 < Pb / Ps < 0.5: Kw = 1.152 -- 0.95•Pb / Ps Case Pb / Ps >0.5: Kw = 0.677
4. Calculate upstream relieving pressure:

*Pup[psi-g]

5. Estimate required effective discharge area:

*W[US gal/min], Pup [psi-g]

6. Calculate Reynolds number:

7. Calculate correction factor for viscosity:

8. Calculate required effective discharge area:

1. With Rupture disk:

2. Without Rupture disk:

Not requiring ASME capacity certification

1. Calculate total back pressure:

2. Effective coefficient of discharge: Kd =0.62 (if Kd is not entered by user).

3. Determine correction factor for back pressure:

1. For conventional and Pilot operated valves, Kw =1.

2. For Bellows valve:

 Case Pb / Ps <0.16: Kw =1 Case 0.16 < Pb / Ps < 0.5: Kw = 1.152 -- 0.95•Pb / Ps Case Pb / Ps >0.5: Kw = 0.677
4. Calculate correction factor for overpressure:

5. Estimate required effective discharge area:

*W[US gal/min]

6. Calculate Reynolds number:

7. Calculate correction factor for viscosity:

8. Calculate required effective discharge area:

1. With Rupture disk:

2. Without Rupture disk: