Archives: Glossary Terms: 119 terms
Lockout/tagout is a safety procedure that ensures hazardous energy sources are isolated and de-energized before maintenance or repair work begins. The process involves physically locking disconnects or breakers in the off position and attaching tags that identify who controls the lock and why. LOTO procedures are mandatory under OSHA regulations for industrial facilities and apply to electrical, mechanical, hydraulic, and pneumatic energy sources.
Mechanical seals are precision devices that prevent fluid leakage between rotating shafts and stationary housings in pumps, compressors, and mixers. They function by maintaining controlled contact between a rotating face attached to the shaft and a stationary face in the equipment casing, with a thin fluid film providing lubrication. Seal selection considers process fluid properties, pressure, temperature, and shaft speed, with configurations ranging from single seals to dual arrangements with barrier fluids for hazardous or critical services.
Modular construction is a project execution strategy where major portions of a facility are fabricated off-site as pre-assembled units, then transported and installed at the final location. This approach shifts labor from field stick-building to controlled shop environments, improving quality, safety, and schedule predictability. Industrial projects use modularization to reduce on-site congestion, address remote location constraints, and compress overall execution timelines.
A motor control center is a floor-mounted assembly containing multiple motor starters, variable frequency drives, and feeder breakers in standardized vertical sections. Each unit typically includes a disconnect, overload protection, and control circuitry for an individual motor load, allowing centralized power distribution and control. MCCs are standard in industrial facilities for managing pumps, compressors, fans, and other rotating equipment from a single location.
NFPA 70E is the standard for electrical safety in the workplace, establishing requirements for safe work practices around energized equipment. Compliance includes conducting arc flash and shock hazard assessments, implementing approach boundaries, specifying PPE requirements, and developing energized electrical work permits. Industrial facilities follow NFPA 70E to protect personnel and meet OSHA’s requirement to provide a workplace free from recognized hazards.
Non-destructive testing encompasses inspection methods that evaluate material properties, detect flaws, and measure degradation without damaging the component being examined. Common NDT techniques include ultrasonic testing, radiography, magnetic particle inspection, dye penetrant, and visual examination, each suited to specific defect types and material characteristics. These methods are essential for verifying weld quality during fabrication, assessing equipment condition during turnarounds, and supporting fitness-for-service evaluations.
Overpressure protection encompasses the devices and systems designed to prevent equipment from exceeding its maximum allowable working pressure during abnormal conditions. Primary devices include pressure relief valves, rupture disks, and pilot-operated relief valves sized per API 520/521 to handle credible overpressure scenarios such as blocked outlets, fire exposure, or thermal expansion. Proper overpressure protection is a code requirement for pressure vessels and piping systems, forming a critical mechanical safeguard in process safety design.
A PID controller is the most common feedback control algorithm used in industrial automation, combining proportional, integral, and derivative actions to minimize error between a process variable and setpoint. The proportional term responds to current error magnitude, integral eliminates steady-state offset over time, and derivative anticipates future error based on rate of change. PID control is applied across virtually all continuous processes, from temperature and pressure regulation to flow and level control.
Pipe routing is the engineering process of determining the three-dimensional path a pipeline takes between connection points while satisfying process requirements, code clearances, and constructability constraints. Routing decisions balance factors including pressure drop, thermal expansion, support locations, maintenance access, and coordination with equipment, structures, and other piping systems. Effective routing minimizes material quantities and complexity while ensuring operability, safety, and compliance with applicable codes and standards.