Description
Book SynopsisThis indispensable book systematically guides you through Pressure Relief Valves and how they work. It shows how protective devices perform an important function in preventing the accumulation of overpressure that can result in failure and the uncontrolled release of stored energy. They are therefore categorised as safety critical items of engineering equipment. The book goes on to show that their design and testing is heavily controlled by published technical standards because many countries are covered by statutory legislation.
The content of the book shows that service damage and degradation mechanisms are outlined for various applications – PRVs and bursting discs are used in a wide variety of process conditions, ranging from clean service to heavily corrosive process fluids. This results in a correspondingly large number of damage mechanisms that can prevent them from working if they are not inspected and tested correctly. Risk based inspection procedures are introduced in this book as a method of minimising the chances of failure, and therefore maintaining high levels of safety.
This Quick Guide to Pressure Relief Valves is intended to provide easily accessible technical information for engineers and technicians involved in the operation, testing and maintenance of pressure systems. It also covers other types of protective devises such as bursting discs.
Table of ContentsPreface.
Where to Start - A Ten-minute Guide to PRVs.
Some Useful Websites and References.
Chapter 1. Protective Devices - An Introduction.
1.1 Terminology.
1.2 Overpressure - causes and effects.
1.3 Pressure relief.
1.4 External accreditations.
1.5 Technical standards.
1.6 Operation and maintenance.
Chapter 2. Design Fundamentals.
2.1 The "relieving system".
2.2 Fluid categorization.
2.3 Pressure classes.
2.4 PRV sizing.
2.5 The high-lift principle.
2.6 Nozzle design.
2.7 Balanced high-lift PRVs.
2.8 Seat types.
2.9 Pilot-operated PRVs.
2.10 Pressure-vacuum valves.
2.11 Thermal relief valves.
2.12 Rupture discs.
2.13 Materials of construction.
Chapter 3. Design Codes.
3.1 ANSI B16.34.
3.2 BS 6759: 1984 - safety valves.
3.3 API RP 576: 2000 Inspection of pressure-relieving devices.
3.4 Other API standards.
3.5 The PED and EN 1268.
3.6 PRV isolation.
Chapter 4. ASME VIII Requirements for PRVs.
4.1 Clauses UG-125 to UG-136.
Chapter 5. Damage Mechanism.
5.1 Chloride attack.
5.2 Stress corrosion cracking (SCC).
5.3 Sour service corrosion.
5.4 High-temperature damage mechanisms.
5.5. Fatigue.
5.6 Fire damage.
5.7 Mechanical damage.
5.8 Damaged seating surfaces.
Chapter 6. PRV Inspection Periodicity and RBI.
6.1 Inspection periodicity and life cycle.
6.2 RBI schemes.
Chapter 7. PRV Inspection and Testing.
7.1 Shop tests.
7.2 In-service PRV testing.
7.3 Stripdown examinations.
7.4 Workshop reassembly and testing.
7.5 Setting of PRV lift pressure.
7.6 Storage and handling of PRVs before reinstallation.
7.7 On-line lift testing.
Final Cut - That RBI thing. . .
Appendix 1. PRV Terminology.
Appendix 2. Technical Data.
Index.
