Pressure Safety Valves - Operation, Maintenance and Inspection

Introduction

Within the boiler, piping and pressure vessel industry, safety relief valves are of most essential importance. Pressure relief valves are the last line of defense against catastrophic failure or even loss of life. The course covers safety valve types, codes & standards and designs, materials, specification and selection, sizing, installation & testing, preventive maintenance procedures, operation and troubleshooting.

A number of different instructional methods are used throughout the course to allow interactive learning and to give practical examples from the manufacturing and service industry to enable the delegates to operate select, size, install, test and troubleshoot safety valves upon course completion.

Safety Relief Valve Sizing Software “ Valvestar “ from LESER Germany will be demonstrated for sizing & selection of relief valves. (Sizing of Safety Valves as per codes, two-phase flow/fire case as per API, pressure loss, back pressure, reaction forces, and noise level). Pentair PRV Size Software will demonstrate for sizing Relief Valves.

Objectives

By the end of the training, participants will be able to:

• Familiarize participants with the functions and applications of safety relief valves, their types, designs, and components.
• Enable appropriate safety valve sizing and selection for liquid, gas and vapor applications
• Train participants to install, inspect, test & troubleshoot a variety of safety valves.
• To increase the participant’s awareness and understanding that the mechanical integrity of relief valves depends jointly on the proper design, operation, condition assessment, and maintenance of the equipment.
• To provide the participants with a clear understanding of the degradation mechanisms that relief valves could be subjected to over their operating life, how to identify them, predict and determine their impact, and what appropriate measures can be taken to prevent and control the resultant damage.
• To provide the participants with the knowledge and failure analysis skills they need to conduct damage and failure analysis so as to prevent similar failures from happening.
• To understand the requirements of industry codes/standards and approval authorities.
• In-situ Testing Techniques – Onsite Testing of Safety Relief Valves.
• Emerging Technologies in Pressure Relieving Devices
• Use Valve Star / PRV size software for Safety Relief Valve Sizing & selection from Leser and CROSBY.

Training Methodology

This is a highly interactive training course with opportunities to advance your opinions and ideas. Participation is encouraged in a supportive environment. To ensure the concepts introduced during the program are understood, they will be reinforced through a mix of learning methods, including lecture-style presentations, open discussion, case studies, simulations, and group work.

Who Should Attend?

Engineers / Supervisors / Technicians from Maintenance Operations Department, Maintenance Service Department, and Inspection & Materials Technology Section.

Course Outline

INTRODUCTION

• SAFETY RELIEF VALVES History
• Pressure Relief Devices (Reclosing, Non-Reclosing)
• Reclosing Pressure Relief Devices
• Pressure Relief Valves
• Safety Valves
• Relief Valves
• Non-Reclosing Pressure Relief Devices
• Rupture Disk
• Breaking Pin devices
• Buckling Pin devices
• Shear Pin devices
• Fusible Plug devices

OVERPRESS URE PROTECTION

• Safety Relief Valves in a Process
• Causes  of  Overpressure  (Blocked  Discharge,  Fire  Case,  Thermal
• Expansion
• Runaway Reaction, Tube Rupture in Heat Exchangers)
• Overpressure Protection Requirements

PRESSURE RELIEF VALVES

WORKING PRINCIPLE & COMPONENTS & SPECIFICATION

• Conventional Pressure Relief Valves
• Pilot Operated Pressure Relief Valves
• Balanced Bellow Pressure Relief Valves
• Power & Temperature Actuated Pressure Relief Valves
• Relief Vs Safety Valve
• Components & Accessories of Relief Valves
• Specifying Pressure Relief Valves

SAFETY VALVES – WORKING PRINCIPLE & COMPONENTS, SPECIFICATION

• Working Principle
• Classification (Actuation, Lift, Seat Design, lever, bonnet)
• Major Components / Accessories
• Locations
• Specifying Safety Valves

CODES & STANDARDS

• Overview of operational requirements
• ASME & API codes and standards - clarifications
• National Board approval
• Main paragraph excerpts from ASME VIII
• Main    excerpts    from    American    Petroleum    Institute    (API) Recommended practices related to safety relief valves

TERMINOLOGY

• Testing
• Type of devices
• Reclosing pressure-relieving devices
• Non-reclosing pressure relief devices
• Dimensional terms
• Operational terms
• Component terms
• Clarification    of    the    terms:    set    pressure,    overpressure, accumulation, MAWP and design pressure (PED versus ASME)

DESIGN FUNDAMENTALS

• Materials of Construction
• Direct spring-operated Safety Relief Valves
• Introduction
• Functionality
• General design
• Design of main assemblies
• Design differences
• Types of spring-operated SRV's
• Controlled safety pressure relief system (CSPRS)

Pilot Operated Safety Relief Valves

• Introduction
• Functionality
• Types of POSRV
• Summary
• DIN designs
• Non-re-closing pressure relief devices

SIZING & SELECTION

• Introduction
• Gas and vapor sizing
• Steam sizing (sonic flow)
• Liquid sizing
• Combination devices
• Two phases of flashing flow
• Two-phase liquid/ vapor flow
• A two-phase system with flashing or non-condensable gas
• Subcooled liquid flashing
• A two-phase system with flashing and non-condensable gas

SAFETY RELIEF VALVE SELECTION

• Seat tightness
• Blowdown
• Service temperature
• Weight and/ or height
• Backpressure
• Orifice size – sizing
• Two-phase flow
• Type of fluid
• Reciprocating compressors
• Liquid
• Materials

INSTALLATION

• Inlet and outlet piping
• Calculating piping losses   
• Calculating outlet piping
• Location of installed SRVs Reaction forces and bracing
• Temperature transmission on installed SRVs Installation guidelines

TESTING

• In situ testing of spring-operated SRVs In situ testing of pilot-operated SVs MAINTENANCE
• Determining maintenance frequency and cost
• Transportation and dirt
• Reinstallation handling and testing of the pressure relief valve
• Maintenance procedure (Pretest, Disassembly, Repair, Assembly & Testing)

TROUBLESHOOTING SRV’S

• Seat leakage
• Chatter
• Premature opening
• Valve will not open
• Valve open above the set pressure
• Valve does not reclose
• Bellows failure
• Springs

NOISE

• Noise from SRV, open vent and associated pipe
• Noise Calculations by SRV Vendor

SPECIFYING SAFETY RELIEF VALVES

• Summary of overall requirements
• Materials, design,  identification,  inspection,  testing,  preparation and shipment

LOW-PRESSURE PROTECTION DEVICES

• Breather valves
• Emergency vents
• Pilot valves
• Tank blanketing

CASE  STUDY:  SAFETY  RELIEF  VALVE  INSPECTION  & EVALUATION