P&I Clubs (Protection and Indemnity Club)
P&ID (Piping & Instrumentation Diagram)
P50 (and P90, Mean, Expected and P10)
PAC (Programmable Automation Controller)
Packing List (Shipping List or Packing Slip)
PADD (Petroleum Administration for Defence District)
PAH (Polycyclic Aromatic Hydrocarbon)
Parabolic Dish (or Parabolic Reflector)
Pareto Principle (or 80/20 Rule)
Particle Size Distribution (PSD)
Particulate Matter (PM) or Particle Pollution
Passive Solar (Building) Design
PAT (Portable Appliance Testing)
PDF (Portable Document Format)
PED (Pressure Equipment Directive)
Peer Economy (or Peer to Peer (P2P) Economy)
Performance Guarantees Statement
Periodontology (or Periodontics)
Persistent Organic Pollutants (POPs)
PERT (Program Evaluation Review Technique)
PHMSA (Pipeline and Hazardous Materials Safety Administration)
Phosphoric Acid Fuel Cell (PAFC)
Photobiological Hydrogen Production
Photoelectrolysis Hydrogen Production
Photovoltaic (Conversion) Efficiency
Photovoltaic-Thermal (PV/T) Systems
PIMS (Process Information Management System)
Pipe Support Spring Register and Calculation
Piping General Arrangement Drawing
Piping Material Take-offs (MTOs)
Piston Compressor (or Reciprocating Compressor)
Planck Constant (h, or Planck's Constant)
Plan-Do-Check-Act or Adjust (PDCA) Approach
Plant and Buildings Lighting Layout Drawing
Plant Cable Tray and Cable Routing Layout
PLC (Programmable Logic Controller)
PLM (Product Lifecycle Management)
Plug-in Hybrid Electric Vehicle (PHEV)
PMC (Project Management Consultant)
PMI (Positive Material Identification)
PMI (Project Management Institute)
PMS (Power Management Solutions)
Polarisation (or Polarization)
Polychlorinated Biphenyls (PCBs)
Polycrystalline Silicon Solar Cell (p-Si) or Multi-Crystalline Silicon Solar Cell (mc-Si)
Polycyclic Aromatic Hydrocarbon (PAH)
Polymerisation (Polymerization)
Portmanteau (or Portmanteau Word)
Positive Displacement Compressor
Potential Explosion Site (PES)
Pound Per Square Inch Absolute (psia)
Pound Per Square Inch Gauge (Psig)
Power Conditioning Equipment (or Power Conditioner)
Power Distribution One line for Instrumentation and Control System
Power Distribution Schedule for Instrumentation and Control System
Power Purchase Agreement (PPA)
PPE (Personal Protection Equipment)
PPI (Payment Protection Insurance)
PRA (Prudential Regulation Authority)
PRCI (Pipeline Research Council International)
Pre Start-up Safety Review (PSSR)
Pre-commissioning and Commissioning Manual
Predicted Environmental Concentration
Preferential Weld Corrosion (PWC)
Pressure Safety Valve (PSV) or Pressure Relief Valve (PRV)
Pressurisation (or Pressurization)
Pressurisation (Pressurization) Testing
Preventive or Preventing Fouling
Primary Insurance Amount (PIA)
Principal Component Analysis (PCA)
Prior Breakdown Method (Construction Price Indices)
Private Internal Rate of Return
Probabilistic Risk Assessment (PRA)
Process & Operational Control Description
Process Datasheet (Data Sheet)
Process Datasheets for Instrumentation
Process Datasheets for Main Equipment
Process Flow Diagrams (PFDs), Utility Flow Diagrams (UFDs) and Heat & Material Balances (HMBs)
Process Safety Information (PSI)
Process Safety Management (PSM)
Process Safety Management System
Process-Based Quality Management System
Procurement Work Process (Cycle)
Production Sharing Agreement (PSA)
Programmable Electronic System (PES)
Programmable Controller System (PC System)
Programme Management (Program Management)
Programme Manager (Program Manager)
Progressive LSTK (Lump Sum Turn Key) Contract
Project Alliancing (or Alliance Contracting)
Project Definition Rating Index (PDRI)
Project Integration Management
Project Life Cycle (or Project Management Life Cycle)
Project Management Programme (Program)
Project Management Body of Knowledge (PMBOK)
Project Portfolio Management (PPM)
Project Summary Schedule (Level 2 Schedule)
Project TF (Task Force) Organisation
Projected Benefit Obligation (PBO)
Promethium (formerly prometheum, Pm)
Proposal Opportunity Assessment
Propylene Oxide (C3H6O or CH3CHCH2O)
Protactinium (formerly protoactinium, Pa)
Proton Exchange Membrane or Polymer Electrolyte Membrane (PEM) Fuel Cell
Provisional Acceptance Certificate (PAC)
PSC (Production Sharing Contract)
PSDS (Product Safety Data Sheet)
Psia (Pound Per Square Inch Absolute)
Psig (Pound Per Square Inch Gauge)
PTSD (Post-Traumatic Stress Disorder)
Public Health Emergencies of International Concern (PHEIC)
Public Official
Public Private Partnership (PPP)
Public Service Obligation (PSO)
Pulse Width Modulated (PWM) Wave Inverter
Purchase Requisition (or PO Requisition)