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The Following links are compliments of our valued sponsor 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.
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.
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 Automation 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.
Reducing Operating Costs on ESD valves with Partial Stroking - As safety standards become more stringent, online testing will become part of everyday life for process plants that want to increase time between shutdowns. However, with frequent manual online testing comes high operational cost
Comparison Between Testing Methodologies to achieve the required SIL level. - The IEC 61508/61511 (Equiv. ISA - S.91 (TR.84)) safety standards are creating more stringent testing requirements for safety equipment. It is clear from existing data (OREDA – Offshore Reliability Data book) that the largest proportion of undetected failures are due to the Final Element. Sensor technology has already integrated ‘smart’ principles for some time. Common failure modes such as plugged lines can be detected by noise signal analysis. The safety system itself has developed to a level where it has both redundancy and a high level of diagnostic coverage. Therefore, that leaves us with the ‘Final Element’.
Acoustic Leak Detection - Acoustic techniques are being employed to detect leakage. It is known that leakage is usually accompanied by acoustic emission. An acoustic emission is a sound wave, or more properly, a stress wave that travels through a material as the result of some sudden release of strain energy. The acoustic energy travels in for of ultrasonic waves through the material of the structure. Thus it may be detected by a remote sensor situated either on the containing structure or in the fluid itself.
Diagnostic coverage Reports for ESD valves - Partial Stroke Testing System System for Emergency Valve Applications - In addition to providing the normal safety shutdown function, the system performs automated diagnostic partial stroke tests, which can be programmed by a configuration software installed on a PC. Various test parameters are measured and recorded during these diagnostic tests. If test parameter limits are exceeded, the valve will alert the operators so that investigative action can be taken. In addition, these test parameters can be trended to create a history of the valve performance and deterioration of valve performance can be detected and evaluated.
ESD Application Reports - A useful series of application reports
9.09
Gas
to flare system ESV & ESD valves - This
application note describes the requirements.
The Following links are compliments of ICEweb sponsor Emerson Process Management.
Verifying the operation of ESD valves - The operation of many industrial processes involves inherent risk. Instrumented Protection Systems are specifically designed to reduce the severity of the impact of an emergency event. These systems, such as Safety Instrumented Systems (SIS) and others, are designed to monitor a process for potentially dangerous conditions. During an emergency event, the SIS activates the valve to move the process to a safe state. What happens if the valve does not move when an emergency event occurs? Personnel safety, equipment damage, and environmental protection could be at serious risk.
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.
The Following links are compliments of ICEweb sponsor Samson Controls.
1208Enhanced
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.
Other Links
08.09
Assessment
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.
08.09
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 safetyusersgroup.com.
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.
Fire Safe Actuators and ESD Valve Fire Shelter
Firesafe Actuators - 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 Controls.
ESD Valve Fire Shelter - This is a neat idea, these cabinets will provide the valve actuators with a minimum of 30 minutes of protection against fire, so that the plant's emergency shut down systems and services can quickly isolate and minimise damage, to protect employees, assets and environment.
HIPPS Systems
Pressure
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
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
page.
Wish to learn more about Safety Instrumented Systems? Our valued sponsor HIMA runs courses. For more information click here.