fmea safety valve factory

I got a safety valve and everything looked good untill i was installing the part. I am a licensed hvac contractor and have been in the field for over 10 years now. Well the safety pilot wasent staying on so i checked the thermocouple and everything was good untill i saw that the safety valve was broken from one side where the thermocouple connects. Now i have a mad costumer because i got a part that does not work

Kalsi Engineering has conducted numerous FMEAs and/or supported FMEAs by performing root-cause investigations for nuclear power plants and for the Electric Power Research Institute (EPRI). Recent projects include performing FMEAs for the three-stage Target Rock Main Steam Safety Relief Valve for two nuclear power plants, Pilgrim and Hatch, and for turbine control and stop valves as part of EPRI’s condition monitoring assessment program.

A detailed and thorough FMEA requires in-depth knowledge of equipment (e.g., valves and other piping/system components) as well as the ability to expertly apply first principles to identify, prove, and/or refute failure modes. A detailed list of FMEA and root-cause investigations performed by KEI™ is provided here.

Independent Review and Analysis of Operability Failure Problems and Proposed Modifications for the Safety Injection System Valves at San Onofre Nuclear Generation Station, Unit 1

The term pressure relief valve is used as a generic all-encompassing term including relief, safety and safety relief valves. However, there are specific definitions associated with the opening action of specific styles of valves. It is important that the correct style of valve be applied to the specific process needs. This is especially significant in the case of liquids and “multi-phase” applications.

Because of their importance to safety, PRVs are a diverse range of solutions found in several facets of a single operation, from steam boilers to low-pressure tanks, that can quickly add up in maintenance costs. For example, a typical 250,000 barrels per day refinery has thousands of PRVs with an annual maintenance cost that can easily exceed $2.5 mil USD. The actual direct costs to repair a PRV normally are relatively low compared to other equipment, but their downtime is critical since operation may not resume without proper overpressure protection.

In certain scenarios, such as multiple PRV installations and fire sizing, valves can be set higher than MAWP and may also be sized for full flow above the maximum accumulation.

Some of the common dimensional characteristics of a PRV include the size and pressure rating of the inlet and outlet as well as the size of the nozzle bore. For some styles of valves, these bore sizes carry a letter designation symbolizing minimum bore size adhering to industry standards. The combination of the area of the valve bore plus the dimensional lift of the valve when open, determines the amount of process fluid the valve will flow.

These standards may also standardize center-to-face dimensions, which allow end users to interchange PRVs from different manufacturers. Although overall height is not normally addressed by standards or recommended practices, it may be an important consideration in piping design and in replacement valve applications.

ASME Code Symbol Stamps are issued to companies meeting all requirements of ASME construction code relating to PRVs. In general, Section I valves are used on direct-fired boilers used for steam generation and power production. In the Oil and Gas Industry Section I, valves may be found in applications such as refinery boiler plants and oil field steam injection systems.

A major difference in the ASME and VR programs is that while an ASME certificate holder is certified to build specific capacity certified models, a VR repair organization is certified to repair valves by section of the ASME code, testing fluid and other related activities (i.e. welding, machining… etc.). A VR Certificate holder may be certified for field repair, shop (depot) repair or both.

The total cost of ownership of a PRV, which includes the initial product cost like engineering, sizing, selection and commissioning, is the tip of the iceberg. Below the water line are all the hidden costs such as direct PRV repair labor, PRV repair parts, administrative, record keeping and other transactional activities, transportation, inventory administration, rigging/scaffolding/pipefitting, etc. Deeper yet is the cost of non-conformance such as unplanned outages, late delivery of repair valves, misapplication of PRVs, emissions, inventory utilization and incorrect maintenance intervals.

The initial purchase cost of a PRV is relatively low. However, due to the potentially large number of PRVs at any given site, the costs associated with record keeping and repair order placement can be substantial, especially if the valves were incorrectly selected or sized from the start. Typical maintenance cycles are from three to five years, and it is not unusual for a single repair cycle cost to exceed the original purchase price of the valve. There may also be considerable costs involved with accessing or retrieving PRVs for testing, inspection or repair. Costs escalate when valves are sent off-site for repair or decontamination.

Physical assets have a life: they are planned and created, used, managed and maintained, and when no longer required prepared for disposal. From the day a PRV is sized and selected until it is finally retired from service, appropriate decisions must be made to ensure their safety and function, specifically regarding the valve maintenance program or asset management. Asset management is the strategic management of these valves during their life in the organization. PRV asset management optimization can reduce cost and increase reliability, while also minimizing unplanned shutdowns and loss of production (see Figure 1).

It is essential to know and understand valve theory and applicable codes as they pertain to sizing and selection. PRV types, capabilities and constraints must be considered when sizing pressure relief valves and close communication between the PRV supplier, end-user and engineering firm is also essential. Although excellent sizing software is available, sizing should only be done by experienced, well trained, technical personnel.

The primary factors when sizing a PRV are set point and flowing capacity. Temperature, composition of process fluid or gas, piping arrangements including existing flange size, dimensional restrictions, back pressure, operating ratios, materials of construction and preferred operating style of valve (pop or modulating…) are among other factors to be considered.

This can have serious consequences and will cause operational problems for years. Some common installation issues include incorrect inlet piping, restrictive outlet piping, the valve is mounted horizontally, back pressure is unknown at time of sizing, or there is an incorrect style of block valve at the PRV inlet.

Once the valve is installed, proper PRV asset management can reduce costs while increasing reliability. Issues and implications of not managing those assets are seen in Figure 2.

Asset management data is a useful tool that can indicate adverse system operational characteristics of a process and provide evidence of poor valve performance. This data can also highlight the need for spare valves in problem applications that can ultimately reduce the downtime during repair outages and installation costs.

Proper asset data records include correct location of valves, identification and records of past service and tracking of future maintenance dates. Valve overhaul data will show past overhaul data for future diagnostics, provide details of job performed, real time status of valves in repair and track parts that need to be replaced at next overhaul.

Failure Mode and Effects Analysis (FMEA)activities are designed to recognize potential failures, evaluate the effects of potential failures in the process and identify the actions that could eliminate or reduce the chance of the potential failure occurring.

The objective of FMEA activities are to enhance the operating performance of the PRVs and minimize failure. FMEA offers greater assurance of PRV safety and performance.

Having this data allows efficient management of internal workflows for valve service. It also enables institution of a preventive/planned maintenance system and an inventory management system.

For operators, this means improved valve reliability and uptime, optimized maintenance planning, resourcing and spending and increased availability of needed parts while improving safety.

To reduce the costs of maintaining PRVs and the associated inspection and testing activities, many end users have found using spare PRVs as an effective strategy. Redundant valves are purchased mirroring the installed PRVs and then kept in storage ready for quick exchange when the installed PRV is removed from service. Using this strategy can allow PRVs to be prepared for installation well in advance of planned STO (Shutdowns, Turnarounds, and Outages) and minimize and simplify the work to be performed during the outage (see Figure 3).

Implementing a spare pool also helps minimize the time employees are exposed to possible safety hazards involved working on scaffolding, etc., while performing the removal and installation work. After the in-service PRV is removed from the site, it is returned for inspection and refurbishment to the spare “pool” where it can be used in a future STO cycle.

“Like for like” sparing of installed valves. Although one of the less flexible and more costly strategies, it does offer immediate back up for installed PRVs and is often used for critical valves. In some cases, the customer may use a “twin” installation such as a Safety Selector Valve allowing for permanent installation of the spare and active PRV.

PRVs have a critical role in maintaining safety and protecting life and property. It’s essential for service providers and operators to know applicable codes and standards and seek expert assistance when sizing and selecting these valves.

To manage the lifecycle costs to reduce maintenance and associated operating costs while improving safety, it is essential to take no shortcuts and follow manufacturer’s recommendations when repairing valves. Experience is critical!

By implementing an asset management program, operators can improve uptime, optimize planning, resourcing and spend. Best results are achieved when operators, valve manufacturers and service providers work together for a common goal.

When planning a check valve installation, the primary goal is to achieve a valve and piping system that offers the longest service life at the lowest cost.

This article describes the methodology for performing a failure modes and effects analysis (FMEA). It explains the methodology with the help of a hot water heater and provides a discussion on the role of FMEA in the design process. The article presents the analysis procedures and shows how proper planning, along with functional, interface, and detailed fault analyses, makes FMEA a process that facilitates the design throughout the product development cycle. It also discusses the use of fault equivalence to reduce the amount of labor required by the analysis. The article shows how fault trees are used to unify...

Some other issues include – incorrect transporting – valves (esp. large and low set pressure) need to be transported vertically so that the plug and spindle weight does not “bend” the spindle causing the plug and seat to rub on each other and therefore scratch the seat over every bump in the road. We have developed some “best practice” type requirements. Basically any valve under 50mm inlet may be transported laying down if packed properly and if set point is over 250kPa – we use foam packed cases (like what expensive cameras etc are sometimes packed in). Valves over 50mm inlet (up to our large valves of 500mm inlets) are bolted vertically to pallets. These pallets are specially built.

For transport, we use steel bases with plywood covers to protect from external environment (this helps with loading and unloading and does a lot for preventing the pallet being laid down). The bases have channels welded underneath to provide forklift capabilities and lifting lugs on the top to allow for lifting to the work area (or just off the truck if there is no forklift available) prior to lifting valve off the pallet.

For storage, large valves are usually on a steel pallet with its cover or heavy plywood pallets with covers. These allow the valve to be bolted down (drillings to suit PCD etc) providing security.

At times we may sprag a large or very low pressure valve to prevent seat / plug vibration but, YOU MUST HAVE A WAY OF ENSURING THAT THE SPRAG IS REMOVED BEFORE PUTTING THE LINE INTO SERVICE. If not the valve becomes just a very expensive and intricate piece of pipe and will not save your plant (and possibly your life) in the event of a process excursion.