
Instrument Air, Flare, and Nitrogen lines may not be hydro tested, but pneumatically tested).

Requirements of upstream/downstream straight lengths.Location and identification of all instruments.Representation is correctly made in line with the standard symbols.Changes in the direction and angles of the line should be clearly shown.Equipment number & appearance on the isometric drawing.Coordinates of equipment against equipment layout.Design pressure, design temperature, test pressure, testing medium, radiography requirement, Heat treatment requirement, painting requirement, and internal coating requirement.Reference number of PEFS (P&ID), GA drawings, line numbers, the direction of flow, and insulation tracing.Plant North: The direction should be selected so as to facilitate easy checking of isometrics with GA.The following information must be included in piping isometric drawings: Dimension is given relative to the centreline of the piping.Isometrics are not drawn to scale but should be proportional to easy understanding.

It shows all information necessary for fabrication and erection. An isometric drawing covers a complete line as per the line list and P&ID.Latest P&ID/PEFS (Process) (Issued signed copy) General Information about Piping Isometric drawings.and is conversant with a drafting tool can draft isometric. A draft person ( piping designer/engineer) who knows to read the piping GA.Generally, isometrics are prepared/extracted by the design group.Isometric is also used to work out the exact MTO requirement.The main purpose of an isometric is to provide all information necessary for the fabrication and erection along with the bill of material required to do so.Piping isometrics are the three-dimensional representation of the line.Types of Lines in Engineering Drawing (PDF)
