In the realm of process engineering, Piping and Instrumentation Diagrams (P&IDs) are crucial tools for visualizing and conveying the design, configuration, and operation of systems. P&ID pump symbols, specifically, are an essential part of these diagrams. They serve as visual shorthand, simplifying the complexity of fluid handling systems, pumps, and associated piping.

This blog takes a deep dive into P&ID pump symbols — what they are, how they are used, why they are important, how to read and interpret them along with guidelines and best practices for creation. For engineers, designers, and operators alike, understanding pump symbols is critical to both interpreting and developing process designs that are safe, functional, and compliant with industry standards.

These symbols represent pumps in a process system. They help visually communicate the type of pump, its operating mode, and its functional attributes. These symbols help engineers, operators, and maintenance personnel easily identify and understand the pumping system’s design and operation. Each symbol is standardized and corresponds to a specific type of pump, ensuring clarity across designs and teams.

• Centrifugal Pump: The most common type of pump used in industrial systems. It is typically represented by a circle with an arrow inside, pointing in the direction of flow. The arrow indicates the direction in which the pump impels the fluid.
• Positive Displacement Pump: These pumps are used for applications requiring constant flow rates, regardless of system pressure. They are typically represented by a circle or rectangle with a slanted line or a dotted line inside, indicating the displacement action.
• Gear Pump: A type of positive displacement pump, often used for high-pressure, low-flow applications. It is represented by a small rectangle or circle with two interlocking gears inside.
• Diaphragm Pump: Another form of positive displacement pump, diaphragm pumps are used for handling viscous fluids. The symbol is usually shown as a circle with a diaphragm-shaped line inside.
• Peristaltic Pump: Peristaltic pumps are used in applications requiring precise flow control, often for chemicals or medical fluids. They are represented by a series of curved arrows around a circle, signifying the squeezing action.
• Screw Pump: Typically used in high-viscosity fluid applications, screw pumps are represented by an ‘S’ or spiral within a circle to signify the screw mechanism used to move fluids.

Listed below are the broad categories of pump symbols in P&IDs that define the pump’s function and usage details:

• Pump Type: Indicated by the specific symbol (centrifugal, diaphragm, gear, etc.).
• Flow Direction: Arrows show the direction in which the fluid flows.
• Control Features: Some symbols will indicate specific control features, such as variable speed or automatic shutdown capabilities.
• Drive Information: Some symbols include supplementary annotations or text to describe operational details, such as the motor, turbines type or drive configuration.

They represent the different types of pumps used in process systems and help simplify complex fluid handling operations. Each symbol visually communicates the pump’s type, function, and orientation, ensuring consistency and clarity across engineering teams. From centrifugal, screw, and gear pumps to diaphragm, metering, and submerged pumps, every symbol follows standardized conventions like ISO or ANSI. These graphical notations also include details such as flow direction, motor drive, or control features. Accurate pump symbols make it easier for engineers, operators, and maintenance teams to interpret, design, and troubleshoot process systems effectively.

Now let’s explore the detailed representation of pumps within P&IDs that we consider;

When reading pump symbols in P&IDs, remember:

• Arrows show direction of flow.
• Annotations may indicate motor, speed, or driver type.
• Shape variations (circle, gears, lobes, spirals) represent pump mechanisms.
• ISO/ANSI standards ensure uniformity across global projects.

Creating a Pump P&ID is a critical step in process engineering projects. This helps ensure clarity in system operation, maintenance, and safety. Listed below are commonly used guidelines that outline the best practices for preparing effective Pump P&IDs:

Define Pump Type and Service

• Identify the pump type: centrifugal, positive displacement, gear, diaphragm, or peristaltic.
• Specify service conditions: process fluid, pressure, temperature, and flow rate.

Include Complete Pump Data

• Pump ID, tag number, and manufacturer details.
• Design flow rate, suction and discharge pressure, NPSH (Net Positive Suction Head), and efficiency.
• Power source and motor rating.

Represent Pump Orientation and Configuration

• Include pump arrangement: horizontal, vertical, inline, or multistage.
• Show suction and discharge connections with proper orientation.
• Indicate mechanical seals or packing arrangement.

Integrate Control and Safety Instruments

• Include flow, pressure, and temperature transmitters near suction and discharge.
• Show control valves, isolation valves, and bypass lines.
• Add alarms, interlocks, and safety relief devices.

Show Suction and Discharge Piping

• Include line sizes, material specifications, and insulation if required.
• Represent suction strainers, filters, or separators upstream of the pump.
• Show discharge check valves and pressure relief valves.

Depict Ancillary Equipment

• Include lube oil systems, cooling water lines, and seal flush lines if applicable.
• Indicate vents, drains, and instrumentation taps.

Follow Standard Symbols and Conventions

• Use standard P&ID symbols (ISA, ISO, or company standards) consistently.
• Maintain clear line identification, direction of flow, and tag numbers.
• Ensure P&ID clarity for operators, engineers, and maintenance teams.

Review and Validation

• Cross-check P&ID with process datasheets, specifications, and equipment layouts.
• Validate for safety compliance, operational logic, and maintainability.
• Conduct peer review to minimize errors and omissions.

Documentation

• Maintain version control and revision history.
• Include a legend or key for easy understanding of symbols and notations.

• Stick to Standard Conventions: Use ISO, ANSI/ISA, or client-specific legend sheets to ensure symbols match accepted standards.
• Consistency is Key: Across all P&IDs in a project, ensure that the same symbol style is used for similar equipment.
• Avoid Overcomplication: A symbol doesn’t need to show every mechanical detail—only those necessary for understanding process operation and control.
• Use Cross – Referencing Efficiently: Use tag numbers and line identifiers to cross reference vessels with other drawings, datasheets, and specifications.
• Consult the Legend Sheet: Always refer to the project specific symbol legend to understand customized symbols or notations.

Developing and interpreting pump symbols is not only the domain of process engineers. It requires input from multiple disciplines:

• Mechanical Engineering: Ensures pump design that matches process needs.
• Instrumentation & Control: Ensures mapping of transmitters, sensors, and control elements.
• Piping Engineering: Manages connectivity, nozzle locations, and routing.
• Safety Engineering: Ensure emergency and relief measures are appropriately represented.

A multidisciplinary engineering company like Rishabh Engineering integrates all these perspectives to deliver P&IDs that are technically sound, compliant, and project ready. Read this blog to explore different piping and instrumentation diagram symbols, how to read P&IDs and how to craft them.

P&ID pump symbols provide a unified visual language that helps engineers, designers, and maintenance teams understand the mechanical systems without ambiguity. By reading a P&ID with the correct symbols, teams can:

• Easily identify pump types and their application
• Understand flow and pressure requirements
• Ensure efficient maintenance and troubleshooting
• Maintain consistent communication across different stakeholders

P&ID symbols for pumps are vital for accurately representing complex pump systems and their integration within process plants. They enable clarity and consistency in system design, operation, and maintenance. Whether creating new layouts or troubleshooting existing ones, standardized pump symbols ensure smooth collaboration across teams and projects. At Rishabh Engineering, through our equipment engineering services, we deliver comprehensive P&ID designs with standardized pump symbols tailored for diverse industrial applications. Backed by a multidisciplinary approach, we ensure that every design meets global codes, safety requirements, and operational efficiency standards.

Our team creates accurate and compliant P&ID designs, ensuring clear communication, safe operations, and efficient system performance.