# Nomenclature
## Symbology
The following is a list of symbology used throughout this guide. Units are SI unless otherwise specified.
| Description | Symbol | Unit |
| ---- | ---- | ---- |
| Density | $\rho$ | $kg/m^3$ |
| Entropy change of vapourisation | $\Delta S_{vap}$ | $J mol^{-1}K^{-1}$ |
| Ideal gas constant | $R$ | 8.314 $J K^{-1} mol^{-1}$ |
| [[Latent heat]] | $\Delta H_{vap}$ | $kJ/kg$ |
## Acronyms
| Abbreviation | Description |
| -------------------------------------------------------- | ------------------------------------------------- |
| [[Carbon Capture and Storage\|CCS]] | Carbon Capture and Storage |
| DCS | Distributed Control System |
| ESD | Emergency Shutdown |
| FAT | Factory Acceptance Test |
| [[The 5 Functional Safety Assessment (FSA) stages\|FSA]] | Functional Safety Assessment |
| HAZOP | Hazard and Operability Study |
| HRA | Hazard and Risk Assessment |
| LOPA | Layer of Protection Analysis |
| MCC | Motor Control Centre |
| PFD | Process Flow Diagram |
| PFD | Probability of Failure on Demand |
| [[PID Controllers\|PID]] | Proportional, Integral, Differential (controller) |
| PST | Process Safety Time |
| RRF | Risk Reduction Factor |
| SAT | Site Acceptance Test |
| SIF | Safety Instrumented Function |
| SIL | Safety Integrity Level |
| SIS | Safety Instrumented System |
| [[Safety Requirements Specification\|SRS]] | Safety Requirements Specification |