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Foreign material control devices selection and application

5. ESTABLISHMENT AND ADMINISTRATION OF FOREIGN MATERIAL

5.5. Establishing and describing administrative controls

5.5.4. Foreign material control devices selection and application

Foreign material control devices are engineered physical barriers to protect the target SSC and/or the FM path to target SSC. The FMC devices may be permanently built in into the SSCs by design (including those that are replaceable, such as filters and resin beds) or they are installed to temporarily cover, plug, dam, secure SSC openings or FM paths as needed, prior to or during the activities.

These devices are the features which are decided and applied based on the anticipation of potential exposures to and the conceptualisation of protection from FM.

5.5.4.1. Temporary foreign material control devices

Temporary FMC devices (also commonly referred as ‘FME devices’) are used when protecting/shielding open systems or critical equipment against the ingress and/or impact of FM (or potential FM). They are used during the time when they are needed, i.e. when there is a risk of FM ingress, and they are removed, which can be very essential, afterwards:

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“Removal of temporary FMC devices after its use is very important to remember and to be aware of, as there have been many occurrences in various industries where FMC devices are becoming the FM themselves because they are forgotten to be removed. As an example, in a well-known event (which is also commonly used in FMM trainings), significant damage was done to gas standby generator when an FM plug was inadvertently left inside an oil supply line when reassembled. Many events have occurred where ‘shipping plugs’ in valves were not removed prior to installing in the system”.

Typical times and places of use of temporary FMC devices include:

— Prior to or during the activities, when systems/equipment are open, to protect the SSC and FM path from existing or generated FM (e.g. welding slag, cutting/grinding debris, dust, dirt, grit, water, oil, small tools, parts and objects) from getting into the system, component or equipment;

— When FMCA boundaries are established and material ingress (and egress to enter or impact nearby equipment) need to be minimised or eliminated to exclude any FM, or potential foreign material, being transported into/from FMCAs and critical areas/equipment;

— During activities when securing tools and material is needed, such that they do not become lose and be a FM (as the FMs created from inadequate and ineffective lanyards have been a particular issue in the industry, and therefore, appropriateness of, and requirements for, lanyards is commonly noted and their selection and use have been explicitly specified in the FMMPs);

— During transportation of components and equipment, when there is a risk of FM ingress and impact, to protect the internals of SSCs from adverse conditions, such as inclement weather or other environmental effects;

— During storage of components and equipment, where equipment and SSCs are unused or any openings are unattended, to prevent FM ingress, generation and accumulation inside, including protection of internals from adverse ambient conditions.

As such, the type and shape of FMC devices vary to include covers, tarps, caps, plugs, pipe dams, bag plugs, tents, cases, totes, sealed bags, tethers, lanyards, tool control/secure attachments, boundary barriers (including markers and signs), etc.

Due to the large variety of system, equipment, components, areas that can have breaches/openings, it is important to ensure that the proper FMC device is selected for the application. In addition to size, fit, form and function of the FMC devices, the ambient conditions, such as ventilation, high temperatures, electromagnetic impact, access and easiness for installation and removal are all factors that need be considered when selecting the proper FMC device. For example, although caps, threaded plugs, bag plugs, tarps may all be applicable for pipe closers, threaded plugs and hard caps are the preferred FMC device to prevent from an inadvertent loss of the device into the system by pressure changes. Another example is the magnetic devices, which cannot not be used in some application where they could interfere with electrical panels.

In addition to the preference of being easy to install and remove, from the common guidance and principles based on the OPEX and lessons learned, the selection and utilisation of temporary FMC devices considers them to be:

— Appropriate and approved for a given application;

— Clean and free from debris, splinters, etc. and not allow the introduction of FM into the system due to their installation or removal activities;

— Sturdy and secured so they will not be drawn in or blown away, for example by a pressure drop or surge of the system, and therefore, paper dams for gas purges, clear plastic bags, rags, or similar materials cannot be used as FMC devices;

— Engineered and marked with weight capacity if located in an area where personnel may have to walk on the device (in case that they are not designed to support a person, then they ought to be clearly marked with ‘NO STEP’, or similar wording);

— Rigid, strong or thick enough to avoid damage to underlying surfaces, for example when covering vertical openings that are susceptible to falling or heavy objects that could damage or penetrate the FMC device;

— Clearly marked by wording and/or colour consistent with the site specific FMMP colour and wording to prevent inadvertent removal or damage (for example, learning from experience, brightly coloured FMC devices are observed to be an excellent method to promote recognition);

— Resistant to melting, breaking, tearing, or other damage prior to or during use;

— Where practical, used on the removed/unattached/disassembled component (e.g. valve bonnet, flange, junction box cover);

— Properly qualified and approved to prevent component degradation and/or damage to the system, component and equipment upon use (for example, in terms of material compatibility, not to cause any type of chemical reaction, e.g. galvanic corrosion);

— Not used on/in pressurised systems unless pressure boundary is evaluated, justified and approved;

— Fire-resistant or fire-retardant;

— Not susceptible to breakage (shattering or splitting);

— Withstand temperatures encountered during task evolution (for example, lightweight nylon covers may melt if placed on hot piping);

— Not deteriorate or decompose with time;

— Not impact SSC's structural conditions or design functions (which was the case in one well known FM related event when, in one nuclear power plant, the demineralised water storage tank imploded (collapsed and ruptured) as a result of FMC device being left on the vent line, disabling design function of a venting equipment by blocking air penetration/venting paths);

— Installed and secured such that their accidental removal or displacement is prevented.

Also, as they may become contaminated with dirt, dust, oil, debris, etc. during the course of the activity, before removing any installed FMC device, a thorough inspection of the device and the area surrounding the device need to be performed to ensure that no FM has built up on the device or around its edges. Therefore, it may be necessary to clean FMC devices before removal.

Similarly, as most of temporary FMC devices may be reused, it needs to be assured that between the use and reuse, they remain clean and preserve their quality. Therefore, in selection of FMCs that are reused, a thorough cleanliness and appropriateness (e.g. sturdiness, intactness, fitness) check is needed to allow their reusability.

Based on their training and knowledge, line workers and line management (as well as the programme coordinators) need to be able to anticipate and recognise when and where the use of which temporary FMC devices is warranted and understand and interpret the implications and limitations relating to their use or reuse.

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5.5.4.2. Permanent foreign material control devices

As discussed in Section 3.2, in anticipation and considerations at design phase, engineered FMC devices/components/equipment are incorporated into the facility design for FM prevention and protection of SSCs. These FMC devices are designed and permanently installed to prevent ingress and transportation of FM. These devices are mainly in forms of filtration, ventilation, flashing and purification systems (e.g. filters, strainers, fuel guards/grids, drains) but also include structuring of particular parts of the system elements, such as debris traps, vent orientations, carefully sized tolerances and shapes in the openings and transportation paths.

It is needed to clearly identify the analysis and design of features that address specific design aspects of permanent FMCs in the original plant design documents. The plant owner and operator later can use this information to establish and incorporate into their comprehensive FMMP during operation. Therefore, design methodologies and tools, as well as the design and operation requirements and functions of permanent FMC devices, need to be clearly defined in the design documents and incorporated in the operational procedures, as applicable. It may also be a good practice to provide a list of particular design features that serve as the permanent FMC control device in the FMMP documents.

However, existence of such design features ought not to lead to complacency or justification for the use (or not use) of temporary FMC devices since the design basis input and assumptions address only specific functions and conditions applicability for designed and permanently installed FMCs.