ICEweb has nearly 100 Control, Instrumentation, Fire & Gas, Safety Instrumented Systems core pages and a total of more than 300 pages - It Really is Cool Engineering - By Engineers for Engineers it must be just about the World's first choice for Technical Information.
Whilst every effort is made to ensure technical accuracy of the information supplied on iceweb.com.au, Keyfleet Pty Ltd and its employees accept no liability for any loss or damage caused by error or omission from the data supplied. Users should make and rely on their own independent inquiries. By accessing the site users accept this condition. Should you note any error/omission or an article offends please do not ignore it, contact the webmaster and we will review, rectify and remove as necessary.
Get seen by the people who use
can be yours
The Following links are compliments of our valued sponsor Metso Automation
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.
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.
Automatic Partial Stroke Testing Prevents Disasters - Janne Laaksonen, Metso Automation - 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.
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.
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?
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.
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.
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.
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.
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.
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.
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)
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 - Thanks to ICEweb sponsor METSO.
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.
9.13 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.
The Following links are from Samson Controls.
Reliability for Final Elements - Process valves,
sometimes also addressed as final elements are in many cases the most decisive
factor when it comes to calculating the SIL level for a safety instrumented
function (SIF). Testing procedures like partial stroke testing can provide
enhanced diagnostic coverage and therefore help to get improved reliability data
for the total loop. Verification of this 'diagnostic data' and proper
integration of these procedures into the safety instrumented system (SIS) and
basic process control system (BPCS) environment at the same time poses a
challenge. New developments on actors and relevant approvals are presented as
well as instrumentation with new functionality to support diagnostic coverage,
different topologies for connection to SIS and BPCS are discussed.
12.12 Functional Safety of Globe Valves, Rotary Plug Valves, Ball Valves and Butterﬂy Valves
12.12 Rotary 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.
12.12 Valve Style Advantages and Disadvantages - This is a useful spreadsheet.
12.12 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.
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.
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.
Double Whammy: The benefits of Valve Signatures and Partial Stroke Testing -by Paul Gruhn and Derek Essam - Many papers have been written over the past five years on the benefits of partial stroke valve testing (see refs1-6). There are many techniques for performing such testing, most of which are mentioned in the draft ISA technical report TR84.0.03. Partial stroke valve testing is one of the most effective techniques for enabling a single valve to achieve high SIL performance. One aspect of testing, however, has not been covered – that of valve signatures.-Thanks to Valve World
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.
The 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.
7.13 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 links are from Emerson
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.
Smart Positioners to Predict Health of ESD Valves - Riyaz Ali and Dr. William Goble - Safety Instrumented Systems (SIS) involve final control elements such
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.
Process ESD Systems - This power point presentation is a large 9.48 Mb download but contains some really useful information on ESD systems and ESD Valves - from Emerson Process Management and Centralian Controls.
- 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.
3.13 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.
Valve Actuators - This is ICEweb's Technical Information on Control and Quarter Turn Valve Actuators.
Looking for Safety Instrumented
Systems Technical Information? See ICEweb's SIS
Wish to learn more about Safety Instrumented Systems? Our valued sponsors Abhisam Software and Triconex run excellent courses.