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

5-76 API RECOMMENDED PRACTICE 581
Tables
Table 6.1—Basic Data Needed for the PRD Module
Data Description Data Source
PRD type
Fluid composition
Service severity
Overpressure scenarios
PRD discharge location
Type of PRD
— Conventional spring-loaded PRV (default)
— Balanced bellows PRV
— Pilot-operated PRV
— PRV with rupture disk
— Rupture disk only
Process fluid mixture components, either mass or mole fraction. Limit
of 10 components in mixture definition.
Severity of process fluid. Choices are Mild, Moderate, and Severe.
The service severity provides the basis for the selection of the default
POFOD and probability of leakage curves.
FAIL TO OPEN
— Mild
— Moderate (default)
— Severe
LEAKAGE
— Mild
— Moderate (default)
— Severe
Provide a listing of the applicable overpressure scenarios for each
PRD. For each overpressure scenario, default values for the initiating
event frequency and the PRD demand rate reduction factor (DRRF)
are provided in Table 5.2. These two parameters when multiplied
together provide an estimate of the demand rate on the PRD
installation.
— Atmosphere
— Flare (default)
— Closed process
User specified
Fixed equipment
User specified
User specified
User specified
PRD inspection history
— Date of testing
— Install date
— Type of test (effectiveness)
— Results of test/inspection
— Overhauled? Yes/No (see
Section 5.1.6)
— Inlet and outlet piping
condition
[see Section 5.2.4 i),1)]
User specified
Protected equipment
details
Fluid inventory
Operating conditions, design conditions, dimensions, damage
mechanisms, GFF, and DFs
Fluid inventory associated with the protected equipment (lbm). May
be less than the RBI calculated inventory due to shut-in conditions,
e.g. reactor discharge valve fails closed.
Fixed equipment
Fixed equipment
Injury costs Cost of serious injury, $ Fixed equipment
Environmental costs
Environmental fines and costs associated with PRD leakage or loss
of equipment containment, $/event
Fixed equipment
Production costs Cost of lost production, $ Fixed equipment
Unit costs Cost to replace unit, $/ft 2 Fixed equipment