What is Instrument Hookup drawing ?.

It is a drawing, reflects the layout of connection pipes used for conveying pressures and differential pressures from process to field instrumentation devices. One can find materials used, the quantity of each and every particular material on the same drawing.

A Hookup drawing is also called Installation drawing, specifies the scope of work between Mechanical and Instrumentation departments.  It is also a detailed drawing showing typical installation of an instrument in a correct manner so that the instrument operates properly and prevent issues which could potentially affect the measurement such as liquid trap in gas impulse.

In general, these hookups provides the details of the installation to ensure proper operation. Instrumentation Construction Personnel has to review and verify certain important points before going for an Instrument erection.

  • Check Tag No of a particular instrument or list of instruments.
  • Scope of work between mechanical and instrumentation.
  • Bill of material such as SS fittings, Tubing, Isolation valves, plugs, manifold block, Transmitter bracket mounting type (Vertical or Horizontal).
  • Check for bulk material for each installation
  • Material type to use to measure based on fluid and its parameters.
  • Position of instrument in reference to process tapping point.
  • The orientation of the an instrument i.e. whether right-side-up, side mounted, upside down etc.
  • The tubing slopes need to be paid attention.

There are two types of Hookup drawings

  1. Process Hookup drawing.
  2. Pneumatic Hookup drawing.

Process Hookup drawing – typical installation for instrument which connects to process.