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Module III: Safety Devices

Wednesday evenings 7:00 – 8:00 p.m. EST.

11 - Safety Requirement of plant & Different types of PRD's

Why "pressure" is so important?
Plant Protection Strategies
Pressure vessel and tanks (different types of enclosures)
Regulatory issues involved in PRV's
Different types of PRD's: PRV's, Rupture discs
PRV Classification based on structure: Weight type, Spring conventional, Bellows type, and Pilot type
PRV Classification based on protected system: Safety Valve, Breather Valve

12 - Six Steps of Providing a Protective Layer

Locating PRD's
Positioning PRD's
Sizing of PRD: Defining Scenarios, Specifying set Pressure and Calculating Release rate, Calculating Required Orifice Size
Selecting right type of PRD
Selecting right type of PRD arrangement
Checking functionality of PRD: Inlet pressure drop%, Outlet pressure drop%, Operating pressure %

13 - PRV Sizing -1

Pressurization Scenarios
Thermal expansion
Control valve Failed/Jammed open
Gas Blow-by
Blocked Flow
S&T Heat Exchanger Tube Rupture

14 - PRV Sizing -2

Calculating Required Orifice Size and selecting the larger standard orifice size
Relief device; Process responsibility or I&C responsibility?
General Sizing Methodology
Clarification of orifice Sizing formula
General form of orifice sizing formula
What is the difference between “Process Sizing” vs. “I&C Sizing”?
PRV Data Sheets
PRD in field

15 - Material Selection

What are we looking for?
Different mechanisms of material loss
Material selection in I&C context
Factors affecting material loss of sensors, control valves and PSV’s
Brief summary of material
Material compatibility