Plant Documentation Series: Plot Plans

Week Four: Plot Plans


What are they?


Plot plans are diagrams illustrating a top-down aerial view of a plant’s physical layout, usually created at the outset of a project. Industrial sites can be large, some spanning miles. Even in smaller sites, diagrams such as P&IDs, PFDs, and Isos, aren’t sufficient to provide personnel or management a “bigger picture” of the plant’s size & scale.


Plot plans are drawn to scale, with markings that help readers derive measurements like distance and location.

A draft of a plot plan
Draft of a Plot Plan | Wermac.org

A plant may have multiple plot plans: an overall plot plan showing the plant (or a large portion of the plant) and detailed plot plans covering more specific areas, floors, or units. The overall plot plan generally contains major equipment groupings (units), buildings, and roads. More detailed plot plans allow all equipment to be included due to their smaller geographical scope.

How are they used?


Plot plans map out the initial construction of a project but have a variety of useful applications well beyond this phase.


They support the development of new facilities including, the placement of equipment, piping and structure steel requirements, and even play a part in preparing initial environmental permits.

A sample plot plan design
Draft Plan | Gillard Architecture, Design & Innovation

During their creation, plot plans manage a balancing act of controlling construction costs and accounting for safety, operational, process, and maintenance accommodations. A few example accommodations include; isolating and grouping hazardous sections away from occupied buildings, providing valve accessibility for operations, and preserving open space for equipment maintenance access.



Once the plot plans are finalized, a variety of different groups will use them during construction like engineering, scheduling, construction, operations, material control, and estimators. Because of the high-level breadth, they increase alignment across project design, construction, and commissioning.


Once construction is complete and equipment is in service, plot plans still serve an important purpose around the plant. They can be used for:

  • Maintaining environmental and governmental permits

  • Emissions dispersion modeling, equipment emissions inspection planning, and emissions monitoring.

  • Navigating personnel through the field, making it easier to locate specific areas and equipment

  • Planning maintenance, new additions, and major projects

  • Egress during an emergency


Finally, plot plans serve as a base layer for other important drawings and assessments. For example,

  • Facility siting assessment, evaluating occupied building potential exposure to explosion, fire, and toxic hazards.

  • Diagrams such as fire water system or underground piping

  • Hazardous area classification (HAC) diagrams, which allows engineers to install equipment with the appropriate electrical classification (to manage ignition risk of potential atmospheric flammable material)


What are the common challenges of using P&IDs?


As we’ve described, plot plans hold a ton of valuable information. However, as they exist today, they tend to be complicated to use.


Plot plans hold large amounts of detail, making searchability and readability an issue. PDF versions of plot plans allow readers to zoom into these areas but often find them highly pixelated.


Like many industrial diagrams, the process for redlining is crucial. Plot plans act as a base layer for many other drawings and assessments, so accounting for changes within the plot plan and across all related documents can be challenging. It is not always straightforward to find diagrams that are directly related to a detailed plot plan. Even minor missed changes can yield major consequences.


How might digitization of plot plans provide a better field experience?


Like other industrial diagrams, our team sees a variety of ways that plot plan digitization can provide benefits to plant personnel:

  • Quickly search & narrow in on small details with improved readability

  • Compare and contrast cost estimates and plant configurations by running plot plan scenarios accounting for safety, process, and operational accommodations, allowing better collaboration with stakeholders.

  • Improve productivity with mobile and augmented reality, “street-view” directions so personnel are always able to find the right location, building, or equipment.

Google Maps Live AR | Android Central
  • Improve the MoC process with a holistic mapping of all key stakeholders and related documentation

  • Improve safety using a live, site-wide layer for managing simultaneous operations, restricting areas with a heightened safety risk, and controlling traffic around the site

  • Use dynamic plot plans as a facility-wide coordination tool to log, view, and approve planned area usage for turnarounds, projects, building use, and new additions.


This blog is part of Cerebre’s Plant Documentation Series. Our previous posts in the series include:


10/12 - PFDs (link)

10/19 - Isometrics (link)

10/26 - Piping & Instrumentation Diagrams (link)


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!