ABSTRACT

The P&ID or Piping and Instrumentation Diagram is the vital piece of documentation needed to do the HAZOP study that precipitates the Contingincy Analysis of a project.

INTRODUCTION

Beware of the so-called Smart P&IDs involving AI. You need Process Flow Diagrams (PFD), Equipment MAWP, Piping Class, material of construction, Insulation, and tracing shown in the P&IDs.

DISCUSSION

Controls such as ON-OFF, feedback, feedforward, cascade, ratio, split-range, etc.,must be shown on the P&IDs. Control valve fail-positions such as fail-closed, fail-open with directional arrow must be shown on the P&IDs. The symbology incudes: PSV for Pressure Relief Valve, PSE for Pressure Safety Elements such as Rupture Disk, Rupture Pin, and Buckling Pin, TSE for Temperature Safety Elements such as the Fusible Plug. Instrumentation Device and Functional Symbols must conform to ISA-5,1,