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Go to Specific Subject: Design of Shutdown
(SDV) and Blowdown Valves (BDV) Emergency Shutdown Valves (ESV) | Types of Shutdown
(SDV) and Blowdown Valves (BDV) | Reduced
Bore Valves | Shutdown
(SDV) and Blowdown (BDV) Underlying Causes
of Failures and Lessons Learnt | Material Selection for Shutdown
Blowdown Valves | Shutdown
Valves (SDV) and Blowdown Valves (BDV) Seat Leakage Classifications
and Standards | Shutdown
Valves (SDV) and Blowdown Valves (BDV) Fire Safe Standards | Valve
Actuators | Shutdown
(SDV) and Blowdown (BDV) Valve Actuator Sizing and Torque Requirements
Coming Soon! Professional Certificate of Competency in the Selection, Commissioning and Maintenance of Shutdown, Blowdown, Severe Service and Choke Valves
Emergency Shutdown Systems (ESD) are a fundamental part of
the safety systems associated with oil and gas, utility and other
hazardous processes. Associated with these systems are specific valves
which are used to isolate and blowdown the processes. These are referred
to as Shutdown (SDV) and Blowdown (BDV) Valves respectively. Under
emergency situations it is critical that these valves operate correctly.
Thus the engineering of the valves and their associated actuators is
paramount in ensuring plant safety. They must meet the Fire Safe and
Reliability criteria determined by IEC16508 and IEC16511. This
Professional Certificate of Competency (PCC) covers the requirements in
detail. In addition, the course addresses Severe Service Valves and
Wellhead Choke Valves. Severe Service Valves are required where the
process can cause damage to conventional valves through erosion, high
noise, cavitation, high vibration, possible mechanical damage to the valve
trim, other components and the process equipment around the valve. These
valves are generally specialist designs that overcome these issues by
"smart" design. Get
Safety of Globe Valves, Rotary Plug Valves,
Ball Valves and Butterﬂy Valves
Enhanced Reliability for Final Elements - Dr Thomas Karte
Emergency Shut Down Valves (ESD) - Quarter-turn valves are the most common ESD control valves for actuation. Automatic control valves are fitted with hydraulic, pneumatic and electric actuators that respond to changes in pressure, flow or temperature, and automatically open or close the valve. Danger and damage from fire at refineries, petrochemical and offshore installations can be minimized by efficient protection of the systems controlling the plant.Remote valve operation station of fire proof actuator with accessories and air reservoir system to guarantee three complete cycle in the event of fire pneumatic operated with “Darchem” fire proof protection - from Samson Controls.
Need for an Industry Standard for ESD valves from an Engineering and Safety Point of View - Meghdut Manna - Tahakum East -Since the Piper Alpha disaster in the North Sea, design of ESD valves has been given top priority and remains to be of great concern for plant safety management. Constant improvements have been made to ensure the integrity of the ESD valves. Essentially, ESD valves should perform their duty (usually closure of valves) under plant demand condition. To meet the production bottom-line, these valves are required to remain open for months, even years, which leads to build up or corrosion in the valve internals. Final control element is the weakest link in the SIS. From the safety users group.
Shutdown Valve - A shut down valve (also referred to as SDV or Emergency shutdown valve, ESV, ESD, or ESDV) is an actuated valve designed to stop the flow of a hazardous fluid or external hydrocarbons (gases) upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment. Shutdown valves form part of a Safety instrumented system - From Wikipedia, the free encyclopedia.
The following References are from Seridium;
Valves Quick Reference Handbook - This 51 page Engineering reference is a huge repository of technical information on valves, accessories and much more.
Guidance on Valves Type Selection - B.Ricardo - This excellent Technical Engineering Resource provides information on Required function, Service conditions, Fluid type and condition, Fluid characteristics, Frequency of operation, Isolation requirements, Maintenance requirements, Environmental considerations, Past experience in comparable conditions, Weight and size and Cost.
Valve Functions and Basic Parts - There are many types, shapes, and sizes of valves, they all have the same basic parts. This technical manual reviews the common parts and functions of a valve.
Application of Valves - In piping systems, industrial valves play a very crucial role in handling fluids. Different types of Valves are used to meet various applications like on-off, throttling, quick open / close, flow diversions etc…these valves find their applications in industries like refineries, Treatment, Effluent Treatment, Food & Beverages, Pulp & Paper Oil & Gas etc. Selection of right type of valves for a particular application is vital for trouble free service. Details of various types of industrial valves for a particular standards & application areas are included.
Shutdown - Isolation Valve Requirements - This document has some useful
information on Shutdown Valves (SDV).
The Following are from Metso Automation
ESD Valve Selection Guide - General ESD Valve Definition - This 14 page document is an excellent Reference - Covers SIS Standards, Specifications, Valves, Actuators, Safety Valve Testing, Materials, Fire Protection, Safety Integrity Level (SIL), Total Life Cycle, Applications, Quality Assurance and Terminology.
The Value of Safety Valves - Juha Yli -Petays - Safety valves are the most important components in the safety loop (sensor, safety logic and final element), because most of the problems that occur are related to the functionality of the final element. It is important to remember that these elements are moving mechanical devices, which operate in very difficult environmental conditions. This makes the need for regular valve testing and for testing while the process is running absolutely essential.
Bringing Intelligence to On-Off valves and Simplifying On-Off Valve Instrumentation - Juha Kivelä - Traditionally, on-off valves have been instrumented by at least a separate solenoid valve and limit switches. Quite often the desired functionality cannot be achieved by using only a solenoid valve and limit switches, which means that additional pneumatic accessories are needed. For example, if the process requires precise valve opening or closing stroke times, these cannot be guaranteed by using only a solenoid valve; but there is also a need for some extra accessories such as throttle valves.
Taking Safety Valve Testing to the Next Level - Juha Kivelä - Today’s safety engineers face increasing challenges every day. Safety requirements are becoming more and more demanding, while the global market situation is simultaneously creating constant pressure to reduce costs. The IEC61511 safety standard requirements state that industrial processing plants must determine the Safety Integrity Level (SIL) for all the different areas of the plant. Based on the area SIL classifications, the plants must then be able to dispatch quantifiable proof of compliance with the requirements.
Valve Design Codes-
A useful list - from Australian Pipeline Valve.
Introduction to Valve Standards - This Technical Reference provides a useful list of Valve Standards - from OMB Valve Specialists.
The Following Technical Articles are from Emerson Process Management;
Smart Positioners in Safety Instrumented Systems - Riyaz Ali and LeRoy Jero - A review of the way microprocessor-based digital valve controllers – otherwise “smart positioners” – can improve the capabilities of safety systems in detecting potential risks and heading them off before they become a danger.
Positioners to Predict Health of ESD Valves - Riyaz Ali
and Dr. William Goble - Safety Instrumented Systems (SIS) involve final control
as emergency shutdown valves, emergency venting valves, emergency isolation valves, etc. These valves are not continually moving like a typical control valve, but are normally expected to remain static in one position and then reliably operate only when an emergency situation arises. Valves which remain in one position for long periods of time are subject to becoming stuck in that position and may not operate when needed. This could result in a dangerous condition leading to an explosion, fire, and/or a leak of lethal chemicals and gases to the environment.
Predicting Health of Final Control Element of Safety Instrumented System by Digital Valve Controller - Riyaz Ali - This paper will discuss testing final control element of SIF loop, on-line, while plant is running, by using smart positioners to perform partial stroke test to detect dangerous failures, which would have remain undetected, if testing were not done.
Plug Valves - This valve construction, simply called
“the rotary valve”- summarizes different valve styles under a generic term.
All of them have one thing in common: a turning valve shaft for adjustments in
valve opening. The form of the obturator varies between a simple drilled-through
cylinder and a complicated eccentrically positioned plug with a spherical
segment surface. To this category also belong armature types which are described
as “cock” valves with a cylindrical or conical plug and a special opening
cross-section whose profile is authoritative for the flow characteristics of the
valve. The so called cock valve, with tapered plug, has been in use for more
than 2000 years and was utilized in earlier days - carved out of wood - to tap
wine. With the development of new, high corrosion resistant materials like PTFE
or PFA which are frequently used for the lining of inferior metallic valve
bodies, these well-known constructions have had a renaissance. This principle is
used, however, principally for ON-OFF services and only seldom for continuous
control applications - from South African Instrument and Control and Samson
Valve Style Advantages and Disadvantages - This is a useful spreadsheet - from Samson Controls.
Valve Types - There is a vast abundance of valve types available for implementation into systems. The valves most commonly used in processes are ball valves, butterfly valves, globe valves, and plug valves. This article provides a summary of these four valve types and their relevant applications - from the University of Michigan.
Valve Types and Design - Valves are the most common single piece of equipment found in DOE facilities. Although there are many types, shapes, and sizes of valves, they all have the same basic parts. This comprehensive technical reference provides useful information covering the common parts and functions of a valve - from constructionknowledge.net
Introduction to Valves - Only the Basics - Valves are mechanical devices that controls the flow and pressure within a system or process. They are essential components of a piping system that conveys liquids, gases, vapors, slurries etc. Different types of valves are available: gate, globe, plug, ball, butterfly, check, diaphragm, pinch, pressure relief, control valves etc. Each of these types has a number of models, each with different features and functional capabilities. Some valves are self-operated while others manually or with an actuator or pneumatic or hydraulic is operated - from World of Piping.
The following Design Parameters are from Seridium
Reduced bore or venturi pattern valves should be selected
when minimum weight, cost, and operating time are required.
The seat (throat) diameter of reduced bore valves should be selected.
If reduced bore valves are used, the following additional criteria should be satisfied:
The increased pressure drop is considered in the design of the piping.
Not to be used in horizontal lines which are sloped for continuous draining.
Drains are installed at all additional low points caused by the installation of reduced bore valves.
Not to be used in erosive applications such as sandy
service, slurries, or fluidized solids without
Not to be used in severe fouling, solidifying, or coking services.
Not to be used in lines specified to be mechanically cleaned or “pigged”.
Not to be used as block valves associated with pressure relief devices and flare pipe headers.
is a Full Port or Reduced Port Ball Valve? - These are
two different types of ball valves. The major difference between a full bore
valve and a reduced bore valve is described here - from Tofine. What
is the Difference between Full Port (Full Bore) and Standard Porting? -
This article describes the difference - from Valveman.
Full Bore or Reduced Bore Ball Valves - Full bore ball valve is a valve that the hole diameter of its ball is the same size with the pipe size. Reduced bore ball valves is a valve that the hole diameter of its ball is not the same size with the pipe size. In minimum the reduced ball valves ball diameter are one size lower than the pipe size i.e. 4 inch pipe and ball diameter is 3 inch (usually symbolized as 4 x 3 inch ball valves). From its definition we can quickly know that the full bore will have less pressure drop and reduced bore will have more pressure drop since reduced bore is just like a restriction orifice that narrowing at the middle part. So when full bore or reduced bore ball valves will be used? - from SZ Valves.
is the Difference between Full Port (Full Bore) and Standard Porting? -
This article describes the difference - from Valveman.
of Valve Failures in the Offshore Oil & Gas Sector - John Peters
- This comprehensive report describes the findings of an assessment study
of data-set information regarding valve problems in the UK Offshore Oil &
Gas Industry. It was undertaken by the National Engineering Laboratory, on
behalf of the Offshore Division of Health & Safety Executive, as part of a
wider initiative to reduce hydrocarbon releases. From the UK HSE.
Emergency Shutdown Valve Study - Industry Operating Experiences and Views; The Way Forward- John Peters - An older study but still very relevant. From the UK HSE.
ESD Valve Failures - This Case Study outlines the criticality of ESD Valves operation and the effects when they fail, It also gives "root causes" and "lessons learnt" - from BG Group.
Valve Corrosion Solutions – This document from Emerson Process
Management is useful and covers the most common forms of corrosion in valves
along with details on NACE standards.
ICEweb's Corrosion Page - Corrosion is a subject that any Instrument Engineer should have knowledge in as selecting the correct equipment and process instruments for a plant is dependant on it. This page provides some excellent technical information about corrosion, forms of corrosion, corrosion effects, how to mitigate corrosion and corrosion monitoring and control. In addition there are Material Selection Guidelines and Corrosion Tables.
ICEweb Control Valve Corrosion Technical Information - This link provides technical information on Valve Corrosion, how it occurs and selection of suitable materials and standards.
for Acceptable Rates of Valve Leakage
- This Technical Information covers standards for leakage
rates including DIN EN 917 for Thermoplastics valves, BS 6364 for
cryogenic valves, along with the three standards used most in the oil and gas,
and petrochemical industry API 598, ANSI FCI 70-2 and MSS-SP-61 - from
Zero and Low Seat Leakage Standards and Test Criteria - This very useful technical paper provides information on the standards, an explaination of zero and low leakage test standards and valve leakage classifications - from Global Supply Line.
Valve Leakage - A Lesson in Leakage - All valves leak. Valves may be said to be "bubble tight" or zero leakage; but in actuality that is just a term that specifies the allowable leakage at that classification. There are six seat leakage classifications defined by ANSI/FCI 70-2-1976 (supersedes ANSI B16.104). This article describes the six valve leakage classifications – from The Valve Pipeline.
Introduction to Valves - Leak testing of Valves - Standards for Acceptable Rates of Valve Leakage - Details API standard 598: Valve Inspection and Testing, MSS standard MSS-SP-61: Pressure Testing of Valves and ANSI standard FCI 70-2: Control Valve Seat Leakage - from Wermac.
The most common standards for fire testing of SDV and BDVs are BS6755, EN ISO 10497 and ANSI/API 607
EN ISO 10497
is an International Standard which specifies fire testing
requirements and a fire test method for confirming the pressure-containing
capability of a valve under pressure during and after the fire test.
Comparative Table of BS6755 and EN ISO 10497 - This details the differences - from Meca Inox
API STD 607 - Fire Test for Quarter-turn Valves and Valves Equipped with Non metallic Seats, 6th Edition
Actuators - This is ICEweb's Technical Information on
Control and Quarter Turn Valve Actuators.
Go to Specific Subject: Compact Valve Actuator Solutions and Systems | Subsea Valve Actuators | Offshore Valve Actuator | High Pressure Manifolds Actuators | Safety Related Systems Valve Actuator Systems | Spring Return Hydraulic Actuators | Spring Return Pneumatic Actuators | Compact Double Block & Bleed (DBB) Valve Actuators | Double Acting Actuator | Compact Actuators in Floating Liquefied Natural Gas (FLNG) Applications | Valve Actuator General Information | Scotch Yoke Design Valve Actuators | Firesafe Actuators | Valve Actuator Standards |Hydraulic Actuator Design and Operation | Electrical Actuator Design and Operation | Control Valve Actuator Design and Operation | Valve Actuator Accessories
Correct specification of torque
values for Blowdown and Shutdown Valves is absolutely critical to ensure
integrity of a facility as the operation of these valves must meet the
reliability and availability requirements. The
following criteria give a guideline of the requirements, however
it must be stressed that any design must meet the Safety and Integrity Level (SIL)
defined for the facility. SDV and BDV valves also must be tested and verified in
accordance with the facility Safety Case, Failure Modes and Criticality Analysis
(FMECA) and Reliability Centred Maintenance (RCM) requirements.
Valve Start to Open Torque
Actuator Spring Start Torque - A safety factor of 100% (i.e. 2 times) should be applied on top of the valve start to open torque. This is defined as the torque at the 'compressed spring state' at the start of the emergency shutdown blowdown operation.
Valve Reseat Torque (Valve Open Torque)
Actuator Spring End Torque - A safety factor of 25% (i.e. 1.25 times) should be applied on top of the valve opening torque. The spring should provide a torque of 1.25 times the valve open torque at its relaxed fully open emergency shutdown blowdown state.
BDV Valve Running
Actuator Spring Running Torque and Air Running Torque (Minimum Torque Produced by the Actuator) - A safety factor of 50% (i.e. 1.5 times) should be applied and maintained on top of the required valve running torque during the close and open valve running cycles.
Valve Start to Close Torque
Actuator Air Start Torque - Pneumatic operator beginning torque should be 2 times the valve closing breakout torque at the start of the plant blowdown reset.
Valve Reseat Torque (Closing Torque)
Actuator Air End Torque - Pneumatic operator end of stroke torque should be 1.25 times the valve closing torque. This is at the end of the closing stroke (The plant operating BDV Valve closed state).
Valve Start to Close Torque
Actuator Spring Start Torque - A safety factor of 100% (i.e. 2 times) should be applied on top of the valve start to close torque. This is defined as the torque at the 'compressed spring state' at the start of the emergency shutdown operation.
Valve Reseat Torque (Valve Closing Torque)
Actuator Spring End Torque - A safety factor of 25% (i.e. 1.25 times) should be applied on top of the valve closing torque. Hence the spring should provide a torque of 1.25 times the valve closing torque at its relaxed fully closed facility emergency shutdown state.
SDV Valve Running
Actuator Spring Running Torque and Air Running Torque is the Minimum Torque produced by the Actuator during the closing or opening cycle. A safety factor of 50% (i.e. 1.5 times) should be applied and maintained on top of the required valve running torque during close and open running cycles.
Valve Start to Open Torque (Valve Start to Open Torque)
Actuator Air Start Torque - Pneumatic operator Start to Open torque should be 2 times the valve opening breakout torque at the start of the facility shutdown reset.
Valve Reseat Torque (Valve Opening Torque)
Actuator Air End Torque - Pneumatic operator end of stroke torque should be 1.25 times the valve opening torque at the end of the opening stroke (The facility operating SDV Valve open state.
Actuator Design and Selection Reduces Down Time - Donald
Weeks - Covers Valve and Actuator Technology, Torque and Actuator Sizing - from
Trends in Pneumatic Spring Return Valve Actuator Selection - Ian M. Turner - When sizing pneumatic actuators for fail-safe valves, torque safety factors can vary depending on project specifi cations, and valve torques can vary from break to open, running and end to close positions. End-users normally determine the valve safety factor during the design stage and valve manufacturers, therefore, do not need to add extra contingencies. Essentially, these safety margins are determined with the goal that the valve should operate smoothly throughout its service life irrespective of the process condition. Increasingly, the safety factor applied when coupled with the specifi ed minimum sizing and normal supply pressure range for actuator selection, can result in selected actuator output torques exceeding the maximum acceptable stem torque (MAST) specifi ed by the valve manufacturer. In the oil and gas industry, for example, three different application categories for safety margin are commonly defined for on/off actuator valves - from Matic Actuators.
Torque Testing - This Covers:
Allowable Stem Torque (MAST) - Ball valves (rotary
valves) are used as ESDVs/BDVs in critical services like shutdown, isolation and
blow down application. Engineers endeavour to ensure
reliability and integrity of actuator and its components. However as far as stem
components are concerned sometimes either give little attention to mechanical
integrity of stem or leave it to valve vendor and assume “Stem design is
sufficient enough to withstand actuator torque”. Unfortunately
this is always the case, Stems do fail!!! If stem key of an ESDV has failed OR
damaged in open position……. What can happen …? It will not close when
there is a close command and this may lead to disastrous situation - from Piping
Closed Loop Breathing - This is a technique to ensure that corrosive or saline air cannot enter the internals of the valve on the breathing side of the valve. It is very popular in the Offshore Oil and Gas Industry and on Coastal Refineries etc - thanks to Rotork for this excellent schematic.
Pressure Surge Damage in Pipeline Systems - Pressure
surges occur in all fluid pipeline systems. There arise two types of damage from
the surge phenomenon, fatigue and catastrophic failure. This paper addresses
this phenomenon from the viewpoint of the available solutions rather than the
mathematics and modelling involved in determining the quantum of the surge
pressure. it has some useful information pertaining to SDV/BDV valves- from
Redesign Blowdown Systems and Alter ESD Practices - When compressor stations are taken offline for maintenance or the system shuts down, the gas within the compressors and associated piping is either manually or automatically vented to the atmosphere (i.e., blowdown). Emergency shutdown (ESD) systems are designed to automatically evacuate hazardous vapours from sensitive areas during plant emergencies and shutdowns. Some ESD systems route these vapours to a flare stack where they are combusted, while other systems simply vent the evacuated vapours to the atmosphere via a vent stack. Partners report a number of opportunities to reduce emissions from blowdown systems and ESD practices, including (a) Redesigning blowdown systems altering ESD practices (b) Installing YALE® Closures (c) Designing isolation valves to minimize gas blowdown volumes (d) Moving fire gates valves in to minimize blowdown volumes. Department of Transportation (DOT) regulations require that emergency shutdown (ESD) systems at gas compressor stations be fully tested on an annual basis. One common practice is to activate the entire system, which discharges very large volumes of gas to the atmosphere. A DOT acceptable alternative is to test each individual dump valve with the discharge stack blind flanged. This greatly reduces gas emissions, but has higher labor costs associated with installing and removing a blind flange on each ESD valve - from the EPA.
The Following are from Metso Automation;
Need a Cryogenic Valve Testing Facility? - The cryogenic valve test centre at Metso Helsinki factory is one of the largest and most advanced dedicated valve test facilities in Europe. It offers customer inspectors the possibility of witnessing potentially hazardous testing operations through shockproof windows in the comfort of a protected, air controlled control room built to the latest safety standards, using a fully computer controlled and logged testing system.
Gas to Flare System ESV & ESD Valves - Both ESD and ESV valves are commonly located in or near the process plant. The flows from different processes are further lead to a flare header which is sized for the certain worst-case volume condition, assuming that relief devices discharge at the same time and other process vents may also be flowing.
Atmospheric Distillation ESD Valves - Atmospheric distillation is the first major process in a refinery. All crude oil entering the refinery, after desalting, passes through the atmospheric distillation column on it’s way to further processing in down stream process units. If there is a shut down of the atmospheric distillation column it means that the entire rerfinery is essentially shut down. The ESD valves are located at the bottom of the atmospheric distillation column and are typically arranged as two valves in parallel piping. The fluid passing through the valves is refered to as heavy bottoms. This fluid is the heaviest cut of a hydrocarbon attainable by atmospheric distillation. The heavy bottoms pass through the ESD valves on their way to the vacuum distillation column for further processing. The ESD valves are used in the normally open condition and are expected to function reliably throughout long process runs, typically four (4) to five (5) years between shut downs.
Oil Refinery and Other Units Processing Hydrocarbons - ESD valves with High Integrity Level - There are fire and explosion risks in the units processing flammable hydrocarbons in case the fluid comes in contact with the atmosphere. If there are high- and low-pressure sections in the plants like e.g. in refinery HDS (hydro desulphurisation) units, the low-pressure side has to be protected against high pressure in case of control failure. Traditionally the number of emergency shut-off valves (ESD) in the process lines in a refinery is not very high. With Neles ValvGuard’s partial stroke testing functionality the ESD valves are automatically diagnosed for their operability while the plant is in operation. With this technology general plant safety can be improved in a cost effective way.
Reliable ESD Valves in Tower Bottom Lines in Heavy Oil Units - Besides fired heaters, the distillation tower bottom areas are the most fire-risky places in a refinery. When the question is of residual oils, high oil temperature, coke formation, sulphur corrosion and possible particles in the oil make the conditions even more severe. Neles metal-seated ball valve with its constructional features and the Neles ValvGuard, partial stroke testing system, used to keep the valves under continuous watch are helping to minimize the fire risks in these areas.
High-End Intelligent Emergency Valve Applications - Jari Kirmanen - Process facilities today are facing growing challenges to meet requirements with respect to the environment, health and safety of the plant personnel while maximizing product output and quality. With increasing energy prices, process plants must further develop their processes and maximize the yield of valuable products in an energy-efficient way. Plant run-time targets are increasing, which also set more challenges on equipment reliability and safety. De-pressurizing or pressure protection, as well as burner emergency shut-off being part of the safety integrity system, is a part of the process industry’s backbone defence against a threat to personnel and equipment. Intelligent partial-stroke devices capable of diagnosing emergency valve condition are more commonly utilized in the hydrocarbon industry. General requirements and challenges together with the benefits of using emergency valves equipped with intelligent partial-stroke devices were considered in the Hydrocarbon engineer magazine article in November 2009 . This article demonstrates more closely how intelligence solutions can be utilized and what kind of added value they bring by introducing three examples of high-end emergency valve applications
Intelligence for LNG Ball Valves - Intelligent valve technology can help to reach the most demanding targets in anti-surge control applications, where fast and accurate operation is needed at extreme service conditions with high pressure differentials and tight shutoff.
Condition Monitoring of Offshore Valve Assemblies - Niklas Lindfors and
Jarkko Räty - Especially in the offshore sector, there is strong emphasis on
minimizing the number of staff working in hazardous offshore environments,
without impacting on reliability. At the same time, it is expected that the
availability of production and the life cycle costs of process equipment should
be optimised. These requirements create the need to improve the capability to
analyse control-valve data from offshore applications - to focus and plan
service actions well in advance. In other words, to enhance the utilization of
existing technologies and increase the use of specialist know-how in order to
enable offshore personnel to carry out the required tasks effectively, safely
and with minimal labour and disturbance to the process itself. (Go to page 4 to
access this information).
Increased Reliability and Safety at Czech Refinery through Partnership in Valve Maintenance - Karel Dvorak and Niko Aunio- In the past, Česká Rafinérská’s strategy has been to carry out turnarounds every four years. This was the first time that the interval was extended to 5 years. After 9 years of operation, some problems were expected, however, on this occasion Česká Rafinérská’s approach was different from that adopted for the previous turnaround. The control valve scope was reduced and the on/off valve scope increased to include overhaul testing based on the SIL classifications. The Metso field survey and Neles ND9000 diagnostics formed the basis for the valve turnaround planning.
Partial Stroking on Fast Acting Applications-Willem-Jan Nuis, Rens Wolters - Partial stroking: This is a widely used method to avoid sticking of a ball valve when it is not operated for some time. It is also used to reduce the actuator size and thus the total cost of the valve + actuator - from Mokveld.
The Following are from Metso Automation;
Partial Closing with Neles Valveguard - Safety engineers throughout the world are struggling with the problem of how to best comply with new and more stringent safety requirements. New IEC requirements state that manufacturers must determine and document precise levels of safety and furnish quantifiable proof of compliance. In light of these requirements, BP feels it is necessary to reassess its traditional safety loop testing procedures. In particular, BP feels it is important to improve its safety valve testing procedures in order to drive costs down and improve plant safety.
Neles ValvGuard "exercises" to Keep Fit - Mark Williamson - An ESD valve, whose mechanism is not often moved, is susceptible to jamming - There is a need to test valves frequently but (with older technology) this is only possible when the process is stopped for major turnarounds, or process shutdowns. Today, the periods between shutdowns is becoming longer and longer. To ensure compliance with safety standards, maintenance engineers therefore face a dilemma. They need more valve testing but they have fewer opportunities to do it when the process is down. Also, frequent manual testing carries a high labour cost. This can be overcomes by automatically “exercising” the valve through a partial stroke at pre-programmed intervals
What You Need To Know About Safety Instrumented Systems (SIS) and Partial-Stroke Testing of ESD Valves - A useful document providing an overview of SIS and Partial stroke testing
Onshore Condition Monitoring of Offshore Valve Assemblies - Niklas Lindfors and Jarkko Räty - Especially in the offshore sector, there is strong emphasis on minimizing the number of staff working in hazardous offshore environments, without impacting on reliability. At the same time, it is expected that the availability of production and the life cycle costs of process equipment should be optimised. These requirements create the need to improve the capability to analyse control-valve data from offshore applications - to focus and plan service actions well in advance. In other words, to enhance the utilization of existing technologies and increase the use of specialist know-how in order to enable offshore personnel to carry out the required tasks effectively, safely and with minimal labour and disturbance to the process itself. (Go to page 4 to access this information)
Depressurizing Systems used to Reduce the Failure Potential for Scenarios Involving Overheating - Sari Aronen -When metal temperature is increased due to fire, exothermic or runaway process reactions, the metal temperature can reach a level where stress rupture can occur. Depressurizing reduces the internal stress, extending the life of the vessel at a given temperature. A relief valve cannot provide adequate risk reduction or safety to depressurize a vessel: it can only limit the pressure from exceeding the process upset point. Therefore, depressurizing valves are used to reduce the risk of losing equipment integrity.
Stroke Testing - Simple or Not - Vendors Promise Increase in MTBF to 13,000
Years - Is this Realistic? - Bill Mostia Jnr - This
Technical Article gives an excellent overview of Partial Stroke Testing and the
use of Valve Signature data - from Emerson Process Management.
Automatic Partial Stroke Testing Prevents Disasters - Janne Laaksonen - Safety engineers throughout the world are struggling with the problem of how to best comply with new and more stringent safety requirements - IEC requirements state that manufacturers must determine and document precise levels of safety and furnish quantifiable proof of compliance. In light of these requirements, manufacturing companies feel it is necessary to reassess their traditional safety loop testing procedures. In particular, they feel it is important to improve their safety valve testing procedures in order to drive costs down and improve plant safety - from SA Instrumentation and Control.
Striking Role of Partial Valve Stroke Testing to meet Safety Integrity Levels
- Bert Knegtering - Partial Valve Stroke Testing or PVST, is a concept to
automatically increase the performance of Safety Instrumented Systems. PVST is a
concept where safety-related valves like ESD valves and shut-off valves are
automatically tested concerning failure modes that are related to valve sticking
and slowing down operation. Current trends in the industry show an upcoming
number of dedicated technical PVST solutions by various automation and
instrumentation vendors. The added value of PVST within the process industries
is a significant reduction of the frequency of required manual periodic valve
proof tests, its related manual test cost and reduced spurious trips due to
manual errors. Partial testing is performed by additional automated test
instrumentation, which can easily be initiated and controlled by the
safety-instrumented systems’ logic solver such as the safety-related PLC. This
paper discusses practical examples of Partial Valve Stroke Testing in which it
appears that SIL 1 rated valves can be upgraded to SIL 2, and off-line proof
test intervals which can be extended from 2 to 5 years. Thanks to Honeywell.
Ensuring that your ESD Valves Work when needed - Emergency Shut-Down valves (ESD) are critical in protection of plant and personnel. These must operate in the event of plant malfunction or fire. The most important requirement for an ESD valve is it’s reliability of operation (open or close) in an emergency. By it’s very nature, it is difficult to test that an ESD valve is "available" without causing a plant upset. The plant is at risk however unless it can be shown that the valve is functioning properly. How can this be done?
Pipeline Riser Emergency Shut Down Valves - Inspection Issues and Recommendations - Regulation 19 and schedule 3 of the Pipelines Safety Regulations 1996 (PSR) require RESDVs to be capable of adequately blocking the flow and this must be achieved with a valve that is suitable and is maintained in an efficient state, in efficient working order and in good repair. The Piper Alpha disaster highlighted the critical nature and functions of riser emergency shut down valves - from HSE (UK)
Investigations into the Immediate and Underlying Causes of Failures of Offshore
Riser Emergency Shutdown Valves - Riser emergency shutdown valves (RESDVs)
are an essential risk reduction measure for offshore installations and are a
legal requirement under the Pipelines Safety Regulations 1996. RESDV failures,
whether arising from a test or a real demand, are reportable to HSE under RIDDOR
and a preliminary survey found approximately 180 cases of failure. Given the
criticality of RESDVs to offshore safety, it was determined that the reasons for
these occurrences should be investigated with a view to focussing inspection
topics and identifying areas for future improvement across the industry. Two
themes have emerged from the causal analysis of RESDV failures: the age of the
valves that failed, and the failure to learn and implement lessons from previous
incidents. The three most common immediate causes were stated by dutyholders to
be corrosion, the age of the RESDV and seizure/sticking. Nearly half of failed
RESDVs have had a previous failure, and over a quarter of failed RESDVs were
brought back into service after cycling and/or lubricating the valves. The root
cause of the failure needs to be determined and acted upon so that it does not
recur, rather than just bringing the RESDV back into service. This report and
the work it describes were funded by the Health and Safety Executive (HSE).
- An essential part of equipment safety is to be able to maintain the
fail-safe position when a fire breaks out. In case of pneumatic linear
actuators, the fail-safe position must be assumed and maintained when air supply
fails or the diaphragm ruptures. Usually, springs are used to perform this task.
They force the valve to move to the fail-safe position when dangerous situations
emerge or damages occur. On failure of air supply, the Actuator springs act
against the pressure of the process medium on the plug to move the valve to the
fail-safe position and keep it there. From ICEweb Sponsor Samson
Innovative Passive Fire Protection Cabinets Extend Margin of Safety for Critical Plant Shutdown Equipment - A novel new range of cabinets to protect critical process equipment in hazardous areas against very high temperature fires has been launched by the field equipment protection specialist Intertec. The cabinets ensure that equipment such as emergency shutdown valves remain operational by keeping them below 60 degrees Centigrade for periods of up to 90 minutes in the event of a hydrocarbon-based fire, to allow time for controlled shutdown. The new 90-minute protection capability - which Intertec believes to be a first in this sector of the industry - has been tested against the ANSI/UL 1709 standard by the test body MPA Dresden.
Innovative Passive Fire Protection Cabinets Extend Margin of Safety for Critical Plant Shutdown Equipment - The cabinets ensure that equipment such as emergency shutdown valves remain operational by keeping them below 60 degrees Centigrade for periods of up to 64 minutes in the event of a hydrocarbon-based fire, to allow time for controlled shutdown - from Intertek,
Relief Valves and HIPPS systems - From ICEweb - These
systems have been utilised in Germany for over 20 years and are proven to be
extremely reliable in very rapid isolation of pipelines. However the technology
is still developing to a point where the required reliability meets all users
needs. They are so reliable that the need for other safety related devices such
as Safety Relief Valves can be minimised. They have the following advantages
- Negating the need for flare systems to be sized for the case of a well failing to close.
- Production piping downrating, giving potential cost benefits of more than 25%.
- Fast inventory isolation within two seconds.
- Huge capital cost savings.
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