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Term |
Definition |
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Anodal Protection |
Known as sacrificial anode. Anodal protection is a
piece of material that corrodes much more readily than the material of
the equipment to which the anode is attached. Zinc is probably the most
common sacrificial |
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Cathodic Protection |
The use of electrical current to provide an excess of electrons to equipment, thereby forestalling corrosion of the equipment material itself. Cathodic protection involves a master station that provides impressed current, as well as various test posts that measure the receipt of current from the master station. This method can also involve a foreign structure, i.e., equipment not under protection of the master station, but close enough to the station’s electrical source to be affected by it. The success of corrosion protection is determined by measuring voltages and currents transmitted by the master station and received at test posts (and foreign structures as applicable). |
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Chemical Data |
Chemical data allows the recording of chemical composition values that may be obtained through laboratory results or through other methods. A list of chemical types belonging to the position of the equipment will appear during data entry. The list of chemical types is associated to the equipment during the creation of the equipment position and key point. The list assists in data entry. In addition to the associated list, other chemical type data can be recorded. |
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Corrosion Circuit |
A collection of equipment that is subjected to similar operating and process conditions. This equipment is put into a circuit to facilitate corrosion monitoring through inspection points attached to equipment. A corrosion management manual (CMM) or pages with details on process conditions, potential problems, corrosion inhibition, or any other information can be directly attached to a corrosion circuit. |
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Corrosion Rate |
Corrosion rate is the rate at which equipment corrodes, normally measured in millimeters per year (mm/y). |
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Coupon |
A unit of material, often resembling a small card and made of the same material as the equipment, that is inserted into an equipment’s environment to act as a sampling medium for corrosion measurement. The coupon’s corrosion and corrosion rate mimic those of the equipment in which it is installed and therefore can be measured to determine the corrosion rate of the associated equipment. Based on a formula, the corrosion rate can be calculated from the dates the coupon was inserted and retrieved and the weight loss of the coupon. |
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Criticality Code |
The criticality code is a code that interacts with the work and inspection modules to automatically reschedule inspections, based upon the remaining life of associated equipment. |
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Criticality Index |
The criticality index is an index that equates a specific criticality code with a set of values that are applied to the equipment’s remaining life to determine the next recommended inspection date. |
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Critical Value |
Critical value is the numerical value calculated through the decision tree hierarchy. Used to determine the criticality code. |
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Decision Tree |
The decision tree is a hierarchical structure of risk items used to calculate the critical value of a risk focus. A decision tree can have numerous formulae to weight various risk items in importance when calculating the critical value. There is no system limit to the number of risk item levels that can be used in any given decision tree. |
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Deviation Check |
This validation check function allows validation of an entered measured value against a range of values and displays an error or warning if the entered value does not fall in the range. The check is made against a deviation table that has range values configured against each inspection aspect. |
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Electrical Isolation |
For equipment not receiving Cathodic corrosion protection, the presence of electrical potential can actually increase corrosion. Such equipment is isolated from electrical currents by insulating material. Measurements are taken on such equipment to determine the effectiveness of the insulating effort. |
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Formula Evaluator |
This function evaluates expressions, formulae, and statements in the user codes that define user forms, DRC forms, and form-based reports. It also allows creation of these forms using the syntax and operators available within the evaluator. |
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Inhibitor |
A chemical compound introduced into a fluid (liquid or gas) environment in order to reduce the corrosion effects of that environment on associated equipment. Chemical concentrations can be measured to ensure the maintenance of the proper concentration of the corrosion-inhibiting compound. An inhibitor can be injected either continuously or in batches. Inhibitors normally work by forming a thin, protective coating on inner surfaces of equipment carrying a fluid or gas. |
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Inspection Point Condition |
Inspection point conditions are the conditions that the inspection point (and therefore the associated equipment) must be in to support proper inspection. For RBI, either on-line or off-line must be stipulated. |
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Leak Data |
Record leakage observed on equipment. Record the location and the specific orientation (location on a conceptual 360-degree scale) of the leak found on the equipment, the failure diagnosed, and the volume spilt. |
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Level |
As with the Datastream 7i equipment hierarchy, a level describes the depth that a risk item occupies in the decision tree hierarchy. Level 1 is occupied by the risk focus. All other levels are occupied by associated risk items. |
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Material Standard |
Materials standards are characteristics of materials as established by international standards organizations, manufacturers, etc. The information is used for numerous data-driven calculations related to corrosion, remaining life, and other analysis items. |
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Minimum Allowable Thickness |
Minimum Allowable Thickness (MAT) is the minimum allowed thickness that equipment can corrode or deteriorate beyond which the equipment cannot operate safely. MAT is a calculated value based on a formula related to equipment and its characteristics. |
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Monitored/Numeric Data |
The data that is collected manually or through data loggers, instruments, or meters from any inspection point, using any measurement method. This data is collected periodically and entered into the system. Electronically collected data can be loaded into the system through bulk-loading utilities. Measurements can be scheduled using the scheduled maintenance function. Coupons, probes, cathodic protection, etc., take the measurements. Corrosion circuits reduce the need for monitoring all points and provide a random monitoring facility as all points in a circuit are expected to have similar corrosion-inducing factors. |
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Monitored Data |
Monitored data are measurements made using different techniques and stored in a DRC form (wall thickness, etc). The DRC form formats used are time series and time series with predisplay. |
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Normalization |
Normalization is a mathematical method of comparing dissimilar numeric values. Normalization in essence sets up a range scale resembling the risk focus code ranges so that a value falls within a range and is converted into the numeric value associated with that range. Unlike the risk focus range, normalization may occur at any level within the decision tree. |
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Pigging |
In a piping environment, pigs are used through runs of pipe. There are two kinds of pigs: intelligent and nonintelligent. Intelligent pigs run through pipe sections and measure wall thickness through the run for the 360 degrees of the pipe’s circumference. Position of the pig is continuously updated through the use of magnetic points placed on the pipe. Nonintelligent pigs also run through sections of pipe, but these pigs have brushes, cups, and other devices for cleaning the pipe interior. The nonintelligent pig pushes debris forward as it advances through the pipe. The debris is collected, weighed, and analyzed to determine potential corrosion problems. |
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Piping Class |
Piping class defines the type of material used in the construction of a pipeline. A piping class defines the material standard being used. Using the piping class reference table, the schedule and the wall thickness can be derived for a given nominal diameter for a pipeline. |
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Probe |
With a similar purpose as a coupon, a probe uses electrical resistance rather than the absence of material to determine corrosion and corrosion rates. Because probes involve electrical measurements, they may be monitored remotely. |
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Process Data |
Process data consists of information related to the proper functioning of equipment, characteristics of its environment, and measurements of performance. Data collected can be recorded by date for the equipment. The amount of data collected will depend on the frequency of the measurement to be taken. Data such as the temperature, pressure, velocity, gas, and liquid flow are recorded. Data from external systems like SCADA, PIMS, or DCS can also be imported and stored for reference and analysis. |
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Ranking |
Ranking is the method in which a user enters numerical scores to be used by the decision tree in calculating the critical value. Rankings can only be entered at the bottom level of each branch of the decision tree. |
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Ranking Level |
In the decision tree, a ranking level is a level where a user may select a ranking value from a list of values. The LOV comes from the next lower level in that tree branch. The ranking value then is applied to successive junctions in the tree (which may include formulae, max/min choices, etc.) to eventually produce a critical value. |
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Remaining Life |
Remaining life refers to the anticipated useful life of equipment. A calculated value based upon standard formulae and the specific results of at least one inspection for the aspect being monitored. |
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Renewal Indicator |
This indicator is used to denote replacement of a coupon or a probe or the replacement of all or part of equipment due to wear or corrosion/erosion. The previous reading’s history is still available against the previous inspection point. New readings start against the new inspection point and corrosion rates are set to zero. |
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Risk Focus |
The risk focus is a general area of concern with respect to risk. Risk focus can relate to equipment, equipment category, or equipment class and would impact the frequency of inspection. By definition, risk focus occupies Level 1 in its decision tree. |
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Risk Focus Code |
The risk focus code is an abbreviated code representing a risk focus. |
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Risk Focus Range |
The risk focus range is a sequence of numerical ranges set up such that a critical value will fall within one and only one range. Each range is linked to one criticality code; thus, a critical value determines the criticality code to be associated with equipment linked to the applicable risk focus. The criticality code determined by the risk focus range is then linked to the criticality index for application in next inspection date determination. |
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Risk Item |
A risk item is a subcategory of risk focus. Used to further detail situations contributing to the overall risk associated with the risk focus within the decision tree. Within the structure of the decision tree hierarchy, risk items may contain formulae to further detail weighted importance to the risk focus. |