Process and instrumentation diagrams P IDs

Before the HAZOP study is started, detailed information on the process must be available. This includes up-to-date process flow diagrams (PFDs), process and instrumentation diagrams (P IDs), detailed equipment specifications, materials of construction, and mass and energy balances. 

Process and Instrumentation Diagrams (P IDs), 29 471 Process annealing, 23 290 Process chemistry, manganese alloy,... 

A fundamental objective of a computer system applied to automate a pharmaceutical GMP operation is to ensure the quality attributes of the drug product are upheld throughout the manufacturing process. It is therefore important that quality-critical parameters are determined and approved early in the validation life cycle. The exercise should be undertaken to a written procedure with base information from the master product/production record file examined and quality-critical parameter values and limits documented and approved for the process and its operation. In addition, the process and instrument diagrams (P IDs) should be reviewed to confirm the measurement and control components that have a direct impact on the quality-critical parameters and data. This exercise should be carried out by an assessment team made up of user representatives with detailed knowledge of both the computer system application and process, and with responsibility for product quality, system operational use, maintenance, and project implementation. This exercise may be conducted as part of an initial hazard and operability study (HAZOP) and needs to confirm the quality-related critical parameters for use in (or referenced by) the computer control system URS. 

Remark 5.2. Industrial implementations of the distributed layer of this control structure would depend on sensor availability. Thus, the holdup of the reactor and the gas phase in the condenser would be stabilized by controlling the pressure in these vessels, while the liquid-level measurements would be used to estimate and control the liquid holdup. A potential process and instrumentation diagram (P ID) for this process is presented in Figure 5.9. 

Figure 5.9 A potential process and instrumentation diagram (P ID) for the reactor-condenser process core.

The instrument schedule is generated from an approved set of Process and Instrument Diagrams (P IDs) and is used to identify all instruments associated with a manufacturing process. The instruments in the schedule are grouped in tag number (loop) order along with an identification of all associated documentation on which they appear. 

The purging steps should he logged, including times at which each vent and drain was opened, and any analytical results (153). Coloring a column process and instrumentation diagram (P ID) at the completion of each pm-ging step is also helpful. 

After considerable evolution, the principal finished product of process design is the process and instrumentation diagram (P ID), eventually issued in what is usually called the approved for construction version (AFC), the definitive successor of various intermediate versions and their revisions. A slice of such a P ID is shown, with some simplifications, in Fig. 3. Obviously, there is a great deal of supporting detail... 

Figure 3 The process and instrumentation diagram (P ID) Shown as a simplified version stripped of some detail (to permit an uncluttered and legible diagram for reproduction herein), the P ID identifies each item of processing equipment, their connectivity and the control instrumentation loops. Not shown, but generally present in the final approved for construction version of the P ID are the details of the piping, materials of construction, pump capacities, etc. Obviously, there is a wealth of other material that accompanies the P ID, but the latter is the centerpiece of the process design package used to execute the plant design.

To apply the principle it is necessary that sufficient information in terms of piping (process) and instrumentation diagram (P ID), draff layout, equipment list, and sizing is available. Normal index value 0—60 light, 61—96 moderate, 97—128 intermediate, 129—159 heavy, and >159 severe. This may be read together with a toxicity index for a chemical plant. This principle is applicable for main plants but not for auxiliaries. Also there is not much correlation with known disasters. 

The analysis team starts with a full set of process and instrument diagrams (P IDs). The team considers possible abnormal events or combinations of events and reviews planned safeguards (e.g. interlocks, relief valves) for adequacy. The final report includes all "what-if" worksheets, a prioritized listing of identified hazards, and the modifications recommended to reduce the hazards to an acceptable level. 

---