The design pressure is calculated based on the system's operating pressure, incorporating a safety margin to ensure safe operation. Here's a breakdown of the calculation:
1. Determine the Operating Pressure (OP):
The operating pressure is the pressure at which the system is normally intended to function. This value is typically provided by a process engineer.
2. Establish the Maximum Operating Pressure (MOP):
The Maximum Operating Pressure (MOP) is determined using the following rule of thumb:
- If OP ≥ 20 bar: MOP = 105% of OP
- If OP < 20 bar: MOP = OP + 1 bar
3. Calculate the Design Pressure (DP):
The design pressure is then based upon the MOP with additional considerations. While the reference only mentions MOP, in practice, other factors can influence the final Design Pressure. Common practices involve multiplying the MOP by a safety factor or adding a further pressure margin. The governing code or standard (e.g., ASME, EN) will dictate the specific requirements for calculating DP. A simplified illustration is given below:
Example:
Let's consider two scenarios:
Scenario 1: Operating Pressure (OP) = 15 bar
- Since OP < 20 bar, MOP = OP + 1 bar = 15 bar + 1 bar = 16 bar
- Design Pressure (DP) would be determined according to the appropriate standard, taking the MOP into account. For illustrative purposes only, assuming a safety factor of 1.15 on MOP: DP = 16 bar * 1.15 = 18.4 bar (Actual design calculations should follow the guidelines of relevant codes).
Scenario 2: Operating Pressure (OP) = 30 bar
- Since OP ≥ 20 bar, MOP = 105% of OP = 1.05 * 30 bar = 31.5 bar
- Design Pressure (DP) would again be determined according to the appropriate standard. For illustrative purposes only, assuming a safety factor of 1.15 on MOP: DP = 31.5 bar * 1.15 = 36.225 bar. (Actual design calculations should follow the guidelines of relevant codes).
In Summary:
The design pressure is derived from the operating pressure, considering a margin for safety and potential fluctuations. The maximum operating pressure (MOP) is an intermediate calculation, and the final design pressure is determined in accordance with relevant engineering standards and codes, possibly using safety factors beyond MOP. Always consult applicable codes for precise calculations.
