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Adding a Process Parameter to a Provision Version

A process parameter defines the amount of time that is needed for the safety process to go into action after a problem is detected. It includes a “calamity value” to determine whether the process will take place in time to avoid the most unfavorable scenario. After you have entered values, the results are shown in a chart.
Note: The provision’s safety type determines whether the Process Parameter tab is available. For more information, see Setting up Safety Types.
This topic explains how to add a process parameter to a draft version of a safety provision.

To Add a Process Parameter to a Provision Version

1.
Open the Safety Provision Version window for the draft version.
2.
In the Properties view, select the Process Parameter tab. This example shows a completed parameter:
3.
Fill in the process values used for the detection values:
Setting Name
Description
Process parameter name
Identifying name given to the parameter. A process parameter defines the amount of time needed for the safety provision to go into action after a problem is detected. It includes a “calamity value” to determine whether the process will take place in time to avoid the most unfavorable scenario.
Response time unit of measure
Unit of measure used for the response and correction time.
Process unit of measure
Unit of measure used for the detection process, for example, lbs per sq. inch or degrees of temperature.
Detection device
Equipment used to determine the problem.
4.
In the Time until consequences boxes, enter the amount of time between the event that caused the problem and its consequences. This value is for informational purposes; it is not shown in the chart.
5.
Enter the detection values to populate the chart.
Setting Name
Description
Set point
The value at which the safety system is initiated (for example, the temperature or pressure at which a problem is detected).
Response time
Amount of time it takes for the detection device to determine that the set point has been reached (for example, the amount of time it takes for the pressure gauge to detect that pressure has reached the high point).
Correction time
Amount of time needed to take correction action (for example, the time it takes the pressure relief valve to open).
Process rate of change
The rate at which the process value changes expressed in terms of the response time unit of measure (for example, 1.000 lbs per sq. inch/second).
6.
Enter the percentages of the set point to calculate the low and high margins of error for the detection device. The low percentage is subtracted from the set point value to arrive at the low margin. The high margin is calculated by adding the percentage to the set point value.
7.
Enter the calamity value, which is the process value at which the most unfavorable scenario occurs.
8.
Save the provision version.
When you have filled in the values and saved the provision version, the result is shown in the chart, for example:
The Correcting chain (seconds) shows the amount of time it takes for the correcting chain to respond to the situation and perform the necessary action (for example, the time it takes for the relief valve to open and release pressure).
Note: If you make changes to the values and save the version, you might need to close and reopen the Safety Provision Version window to refresh the chart.
9.
You can provide supporting information in the Description and Remarks tabs.