The Iso, as isometric are commonly referred, is oriented on the grid relative to
the north arrow found on plan drawings. Because iso's are not drawn to scale,
dimensions are required to specify exact lengths of piping runs. Pipe lengths
are determined through calculations using coordinates and elevations. Vertical
lengths of pipe are calculated using elevations, while horizontal lengths are
caculated using north-south and east-west coordinates.
Piping isometric are generally produced from orthographic
drawings and are important pieces of information to engineers. In very complex
or large piping systems, piping isometrics are essential to the design and
manufacturing phases of a project. Piping isometrics are often used by
designers prior to a stress analysis and are also used by draftsmen to produce
shop fabrication spool drawings. Isometrics are the most important drawings for
installation contractors during the field portion of the project. Each pipeline
in a process or power plant is detailed by at least one piping isometric
drawing. These are not drawn to scale but include sufficient dimensions and a
material take off list to ensure accurate procurement, fabrication, and
erection of the pipeline. A pipeline isometric can show an entire piping system
with a network of connected pipelines, a single pipeline, or a single spool
with prefabricated assembly. At each point where a pipeline connects to
equipment or to another pipeline.
Piping isometric allow
the pipe to be drawn in a manner by which the length, width and depth are shown
in a single view. Isometrics are usually drawn from information found on a plan
and elevation views. The symbols that represent fittings, Valves and flanges
are modified to adapt to the isometric grid. Usually, piping isometrics are
drawn on preprinted paper, with lines of equilateral triangles form of 60°. To
read a Piping Isometric is a pipe into a isometric view, is always drawn by a
single line. This single line is the centerline of the pipe, and from that
line, the dimensions measured. So, not from the outside of a pipe or fitting.