Condition Assessment Techniques

The pipes in water distribution and transmission systems are difficult to inspect for damage due to their location below the surface of the ground. This difficulty has led water utilities to rely on techniques such as breakage records, leak detection, and water audits to determine the health of their systems. While these techniques have been shown to be very useful in prioritizing repairs and replacements, they have the disadvantage of being reactive in nature. In each case, problems with the water system only become apparent after the pipes have failed in some manner [7]. 

Zone water Cheap Does not give the precise 

Sonic/acoustic leak detection Widely practiced Known to find leaks accurately Known to find leaks of different sizes Operates from outside the water line Percentage of leaks missed by the technique is unknown Currently works best in metal water lines Cniy gives information on the current condition of the line (the tool has little predictive value) Background noise problems 

Remote field inspection (hydroscope) Most advanced technique currently available Detects areas of corrosion pitting, as well as through holes Can be used to give an estimate of the future life of a line More expensive than leak detection Requires access to the inside of the water line, which may require cleaning Knowledge of the relationship between pit size and residual life of the pipe is not yet complete Limited to pits of less than 3 cm in size. 

Magnetic flux leakage Established technology in oil and gas industry Known to be capable of detecting small defects and through holes in steel pipe Not yet commercially available for water lines Requires access to and complete cleaning of the inside of the pipe 

---

Using formalized risk assessment techniques for industrial ventilation projects may complicate the issue more than necessary. The work environment and its exposure conditions are the focus. However, when evaluating new technology, including waste management, the risk assessment approach may be valuable. 

Although certain conditions very often lead to a particular type of attack, attempts to categorise soil corrosion in this way cannot be made on a general basis and most corrosivity assessment techniques categorise the soil as reacting to bare steel or iron in one of four ways ... 

The data for assessing the role of formaldehyde in the oxidation of hydrocarbons below 400° C. are summarized in Table IV. It is evident that generalizations at this time are premature, and it is difficult to determine whether the difference reported for the various hydrocarbons are indeed characteristic of the individual species, or that such extraneous effects as variation in surface conditions, sampling techniques, precision of analytical methods, or reactions between end products such as peroxides and aldehydes are significant. 

The term species generally refers to the molecular forms of an element or a cluster of atoms of different elements in a given (in this case solid) matrix (Bernhard et al., 1986a). The term form is also used to indicate uncertainty or lack of knowledge about the exact nature of the species one expects to find in an environmental sample. Conditional speciation assessment techniques like sequential extractions or leaching tests are not able to yield information at the true molecular level in solid phases thus the more general term form is used rather than species when referring to the results of such techniques commonly applied to date to soils and sediments. 

The two-stage module of the PUF sampler enables determination of suspended particulate matter concentrations by pre- and post-weighing of the four inch glass-fiber filter. Because relative differences in suspended particulate matter are of concern, this evaluation can be performed immediately upon the collection of the samples and can be used to aid site personnel in the assessment of dust suppression techniques and evaluation of meteorological conditions. This technique for the determination of suspended particulate matter concentrations should not be directly compared to national ambient air-quality standard for Total Suspended Particulate (TGP) because the filter size, sample flow rate, and sample volume do not conform to the sampling procedures outlined in the Code of Federal Regulation 0, Part 50.11, Appendix 3 for TSP sampling, however, it does provide accurate re-sult s. ... 

Mass accumulation probes as the name suggests, are used to obtain a deposit that can be weighed, i.e. a direct measurement of the fouling per unit area of probe for given conditions. The technique has also been used to assess corrosion under the conditions within a combustion space. 

The Safety Case produced for the Windscale Vitrification Plant in 1994 included a detailed and comprehensive assessment of fault conditions in the plant using HAZOP and Probabilistic Risk Assessment techniques. The Safety Case identified a number of major hazards. These major hazards, along with the protective measures, Operating Rules, and Safety Mechanisms designed to prevent these hazards or to mitigate them are briefly described below. 

Controlled electrochemical experiments are designed to probe select aspects of the formic acid electrooxidation reaction as a function of material selection and/or experimental conditions. Unfortunately, the selected experimental technique employed imposes deviations from a complex three-dimensional catalyst layer used in an operational DFAFC and thus results in inconsistencies between techniques. Assuming the current-potential relationship is always directly correlated to Faraday s law for charge and CO2 production, the assessment techniques can be broken down into three general categories (1) indirect correlation, (2) desorbed product detection, and (3) direct catalyst surface analysis. 

Science of accelerated testing quantitative assessment technique for corrosion rate in difficult electrolytes Prediction CGC III Accelerated corrosion testing under controlled laboratory conditions that quantitatively correlates to observed long-term behavior in service environments... 

Devices with an lEC 61508 claim limit have value for owners/operators in ensuring safety requirements are documented and satisfied by the manufacturer. However, an lEC 61508 SIL claim limit does not necessarily imply the device is reliable or has documented any actual usage in process sector applications. lEC 61508 claim limits can be obtained through analysis and assessment techniques only, and since no field experience is required to make a claim limit or obtain certification, owners/operators should use caution when specifying such devices for SIS applications unless the reliability of the device in actual operating conditions are known. 

The conversion to lead-free materials requires a reassessment of these experimental tools and field-life assessment techniques. New materials and failure modes need to be adequately captured in numerical and experimental test methods to model correctly the sort of thermal and mechanical conditions that an interconnect would be exposed to in field operating conditions. 

Assessment techniques have been sharpened up and emphasis has now shifted from a degree of reliance on the robustness of systems design assumptions to the role of the systems assessor in providing concrete evidence that systems will function to specification under all conceivable multiple fault conditions. 

Any condition assessment should be continued until the cause(s) of the observed deterioration have been clearly identified. It is useful to start with non-destructive techniques (e.g. potential mapping to locate cor-... 

The purpose is to identify circumstances which could lead to the accident under credible conditions. In order to do this we need to identify all the contributing failures and events which need to combine to cause the accident (see Fig. 4.1). This may require a number of hazard assessment techniques in order to identify appropriate... 

Because of the relatively high cost of the CFRP rehabilitation techniques as compared to more conventional construction methods, the use of these materials is primarily for targeted structural repairs and upgrades following pipeline condition assessment. 

Characterization of zeolites is primarily carried out to assess tire quality of materials obtained from syntliesis and postsyntlietic modifications. Secondly, it facilitates tire understanding of tire relation between physical and chemical properties of zeolites and tlieir behaviour in certain applications. For tliis task, especially, in situ characterization metliods have become increasingly more important, tliat is, techniques which probe tire zeolite under actual process conditions. 

---