Instrument Hookup drawing

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

Hook up drawing is also called Installation drawing, describes the scope of work between the Mechanical and Instrumentation departments.

It’s also a detailed drawing showing the distinctive installation of an instrument in a correct manner so that the instrument operates properly and prevents issues that could potentially affect the measurement such as liquid trap in gas impulse.

Generally, these hookups provide the details of the installation to ensure proper operation. Instrumentation Construction workforce has to review and verify certain important points before going for an Instrument erection.

#Check the Tag number of an individual 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) mounting bracket type,
# Check for bulk material for each installation
# Type of material to use to measure based on fluid and its parameters.
# Position of the instrument in reference to the process tapping point.
# The orientation of the 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 Hook up drawings

  1. Process Hook up drawing.
  2. Pneumatic Hook up drawing.

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

Pneumatic Hookup drawing – typical installation for an instrument which needs instrument air, for the example control valve.