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Plant Documentation Series: Isometrics (ISOs)

Week Two: Isometrics (ISOs) or Piping One-line Diagrams ("One-lines")

What are they?

There are a variety of industries and vocations that use isometrics (ISOs) – from product design to navigation to interior decoration. For industrial settings, ISOs, or piping one-line diagrams (“one-lines”), present a detailed rendering of a piping section, displaying its 3D orientation in 2D format. They help users visualize piping orientation and detail without having to navigate out into the field.

Sample Isometric Drawing | Photo: 3D Laser Scanning Solutions

ISOs include detailed information about each section of piping including:

  • Components such as valves, flanges, reducers, expanders, joints, and welds

  • Associated information such as size, type, dimensions, line number, material code, etc.

How are they used?

During the initial construction project, piping engineers & designers create isometrics for piping stress analysis, parts cost estimation, ordering, and fabrication. Evaluating and designing a proper pipe support system is critical in maintaining piping, personnel, and environmental safety.

Once the equipment is in service, ISOs are maintained and updated with any changes in the field. Because ISOs help users visualize piping details and routing, they can be a great complementary tool for daily and periodic tasks, such as troubleshooting, hazard analyses, project scope analyses, and hydraulic modeling. In addition, the inspection team may utilize ISOs to document failures, inspections, and repairs.

Challenges in using Isometrics

While isometrics are a valuable resource in the field, there are common pain points that plant personnel encounter when trying to use them:

  • Accessibility – Compared to P&IDs and PFDs, accessibility to these drawings is typically more limited. Sometimes, these drawings are stuck in siloes, only available within the inspection or mechanical engineering departments. Lack of accessibility reduces their usage across the plant, including the tasks mentioned above.

  • Searchability & Navigation – Since ISOs are detailed and cover a relatively small section of piping, the ISO drawing database can be overwhelming. When an engineer or operator performs field tasks, it is often time-consuming to find the right piping section within the ISO database and navigate between drawings.

  • Maintaining Accuracy – Like other industrial drawings, lack of use leads to accuracy issues. Limited accessibility and familiarity reduce the frequency of updates, which erodes trust in drawing accuracy.

  • Readability – Personnel outside of mechanical engineering may have difficulty fully understanding/picturing the piping orientation given the drawing format (a 30⁰ view from the horizontal plane).

Predictions of liquid holdup in horizontal pipes with BP neural network | Energy Science & Engineering

How ISO Digitization can support a better field experience:

Our team sees a variety of ways that ISO digitization can provide benefits to plant personnel:

  • Improve the trust and reliability of process safety information, enabling consistent and pervasive ISO use

  • Improve workforce safety by reducing field task time, such as supporting initial project scope estimation.

  • Conduct faster, smarter troubleshooting and improve plant health, safety, and environmental information

  • Quickly search an entire plant or facility for specific piping configurations, classes, types, etc.

  • Support and improve piping system hydraulic models with quick access & integration of information such as equivalent length, distance, elevation changes, fitting types, sizes, etc.

  • Optimize piping consolidation decisions with the integration of piping data and financial data

Have ideas or see something missing? Let us know what you think!


This blog is part of Cerebre’s Plant Documentation Series.

Week One: Process Flow Diagrams (& Heat and Material Balance)

As the industrial world races into digital, plant documentation is an important tool for everyday decisions. Specifically, there are many different kinds of industrial drawings used to support process, safety, mechanical, and management decisions.

We see tremendous opportunity in how the digitization of these documents can support a variety of digital and field objectives and want to share that with you!


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