API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

1-10 API RECOMMENDED PRACTICE 581
A risk assessment and management process that is focused on loss of containment of pressurized
equipment in processing facilities, due to damage mechanisms. These risks are managed primarily through
equipment inspection.
3.1.66
risk driver
An item affecting either the probability, consequence, or both such that it constitutes a significant portion of
the risk.
3.1.67
risk management
Coordinated activities to direct and control an organization with regard to risk. Risk management typically
includes risk assessment, risk mitigation, risk acceptance, and risk communication.
3.1.68
risk mitigation
Process of selection and implementation of measures to modify risk. The term risk mitigation is sometimes
used for measures themselves.
3.1.69
risk target
A level of acceptable risk that triggers the inspection planning process. The risk target may be expressed in
area (ft 2 /year), personnel (serious injuries/year) or financial ($/year) terms, based on the owner-user
preference.
3.1.70
safe dispersion
Occurs when a nontoxic, flammable fluid is released and then disperses without ignition.
3.1.71
side-on pressure
The pressure that would be recorded on the side of a structure parallel to the blast.
3.1.72
SLAB
A model for denser-than-air gaseous plume releases that utilizes the one-dimensional equations of
momentum, conservation of mass and energy, and the equation of state. SLAB handles point source groundlevel
releases, elevated jet releases, releases from volume sources, and releases from the evaporation of
volatile liquid spill pools.
3.1.73
soil porosity
The percentage of an entire volume of soil that is either vapor or liquid phase (i.e. air, water, etc.). Clays
typically have higher values due to their ability to hold water and air in its structure.
3.1.74
source model or term
A model used to determine the rate of discharge, the total quantity released (or total time) of a discharge of
material from a process, and the physical state of the discharged material.
3.1.75
system
A collection of equipment assembled for a specific function within a process unit. Examples of systems
include service water system, distillation systems, and separation systems.