Archives: Glossary Terms: 119 terms
Pipe spools are pre-fabricated pipe sections consisting of straight pipe, fittings, flanges, and welds assembled in a shop environment before shipment to the construction site. Shop fabrication allows controlled welding conditions, easier quality inspection, and parallel work that compresses project schedules compared to field stick-building. Spool drawings extracted from the 3D model define each assembly’s components, dimensions, and weld locations for fabrication and tracking.
Pipe stress analysis is the engineering evaluation of forces, moments, and stresses in piping systems to verify they remain within code-allowable limits under all operating and occasional load conditions. The analysis considers thermal expansion, internal pressure, deadweight, wind, seismic loads, and dynamic events to determine support locations and protect connected equipment nozzles from excessive loads. Results drive support type and placement, expansion loop sizing, and spring hanger selection per ASME B31 or applicable codes.
Piping flexibility is the capacity of a piping system to absorb thermal expansion, settlement, and equipment movements without exceeding allowable stress limits or imposing damaging loads on connected equipment. Flexibility is achieved through routing geometry, directional changes, expansion loops, and mechanical expansion joints that allow controlled movement. Insufficient flexibility causes overstressed pipe, failed supports, and equipment nozzle damage, while excessive flexibility may create vibration problems or require additional supports.
A programmable logic controller is a ruggedized industrial computer designed to execute discrete and sequential control logic for machinery and processes. PLCs receive inputs from field devices like switches and sensors, process programmed logic, and drive outputs to actuators, valves, and motor starters. These controllers are preferred for standalone equipment packages and batch processes where fast scan times and deterministic response are required.
Pneumatic controls are devices that use compressed air to regulate, actuate, and automate equipment and processes. Components include air-operated valves, actuators, positioners, and logic elements that provide reliable control in environments where electrical systems pose ignition risks or where simplicity and fail-safe operation are priorities. Pneumatic control systems remain common for valve actuation in process plants, often integrated with electronic control systems through I/P transducers.
Power factor correction improves the ratio of real power to apparent power in an electrical system by reducing reactive power demand. This is typically achieved by installing capacitor banks or synchronous condensers that offset the inductive loads from motors and transformers. Correcting poor power factor reduces utility penalty charges, lowers current draw on distribution equipment, and frees up system capacity for additional loads.
Predictive maintenance is a condition-based strategy that uses monitoring data and analysis techniques to anticipate equipment failures before they occur. Methods include vibration analysis, thermography, oil analysis, and ultrasonic monitoring to detect early indicators of degradation in rotating equipment, electrical systems, and process components. PdM programs optimize maintenance timing, reduce unplanned downtime, and extend equipment life compared to reactive or fixed-interval approaches.
A pressure relief valve is a spring-loaded or pilot-operated safety device that automatically opens to discharge fluid when system pressure exceeds a predetermined set point. Once pressure drops below the closing pressure, the valve reseats to allow normal operation to continue. PSVs are sized and selected per API 520 for specific relief scenarios and require periodic inspection and testing to verify proper function throughout their service life.
Preventive maintenance is a time-based or usage-based strategy that performs scheduled maintenance tasks at predetermined intervals regardless of equipment condition. Activities include lubrication, filter changes, belt replacements, and component inspections according to manufacturer recommendations or historical failure data. PM programs reduce unexpected failures compared to run-to-failure approaches but may result in unnecessary maintenance on equipment that hasn’t degraded.