Criteria of Protection

The effectiveness of cathodic protection in practice can be established in more than one way, and several criteria have been used in the past to prove whether protection is complete. For example, the observed number of leaks in an old buried pipeline is plotted against time, noting that leaks per year drop to a small number or to zero after cathodic protection is installed. Or the hull of a ship can be inspected at regular intervals for depth of pits. 

It is also possible to check effectiveness of protection by short-time tests, including the following measures  

Coupon Tests. A weighed metal coupon shaped to conform to the outside surface of a buried pipe is attached by a brazed connecting cable, and both the cable and surface between coupon and pipe are overlaid with coal tar. After exposure to the soil for a period of weeks or months, the weight loss, if any, of the cleaned coupon is a measure of whether cathodic protection of the pipeline is complete. 

Colorimetric Tests. A section of buried pipeline is cleaned, exposing bare metal. A piece of absorbent paper soaked in potassium ferricyanide solution is brought into contact, and the soil is returned in place. After a relatively short time, examination of the paper for the blue color of ferrous ferricyanide indicates that cathodic protection is not complete, whereas absence of blue indicates satisfactory protection. 

Both the coupon and the colorimetric tests are qualitative and do not provide information about whether just enough or more than enough current is being supplied. 

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An archive is established and meets all the criteria of protection against fire, flood, and other catastrophic data loss. 

The theory of a highly protected risk led to the idea of codes to regulate protection. These set minimum criteria of protection for the good of mankind. The two most prevalent codes are concensus codes and model building codes. 

The cathodic protection of reinforced concrete structures is, thus, proven technology, and the problems being currently encountered deal with criteria of protection, design and inspection of the installation. 

Thermal effects on aquatic organisms have been given critical scientific review. Annual reviews of the thermal effects Hterature have been pubUshed beginning in 1968 (12). Water temperature criteria for protection of aquatic life were prepared by the NAS in 1972, and these criteria have formed the basis of the EPA recommendations for estabUshing water temperature standards for specific water bodies (13,14). 

States have made substantial recent progress in the adoption, and EPA approval, of toxic pollutant water-quahty standards. Furthermore, virtually all states have at least proposed new toxics criteria for priority toxic pollutants since Section 303 (c) (2) (B) was added to the CWA in February of 1987. Unfortunately, not all such state proposals address, in a comprehensive manner, the requirements or Section 303 (c) (2) (B). For example, some states have proposed to adopt criteria to protect aquatic hfe, but not human health other states have proposed human health criteria that do not address major exposure pathways (such as the combination of both fish consumption and drinking water). In addition, in some cases final adoption or proposed state toxics criteria that would be approved by EPA has been substantially delayed due to controversial and difficult issues associated with the toxic pollutant criteria adoption process. 

Depending upon the design criteria of the installed suppression system, an unsuppressed explosion overpressure of around 7 to 10 bar is reduced to a suppressed reduced explosion overpressure which lies in the range of Fred,max = 0-2 to 1 bar. Thus, vessels need to be explosion resistant for an overpressure of maximum 1 bar (ISO Standard 6184/4, Explosion Protection Systems Paii 4 Determination of Efficacy of Explosion Suppression Systems, Geneva, 1985). 

In the same way that potential differences can occur due to different mobility, they can also occur due to different adsorption of ions. There are therefore a large number of possibilities for potential errors in the field of reference electrodes [2], which, however, are generally less than 30 mV. Such potential errors can be neglected in the application of protection potential criteria, but they can lead to increased error in the evaluation of voltage cones (see Section 3.3.1). Equation (3-4) can be used for their evaluation in this case. It explains, for example, the increased... 

In this section the pragmatic protection criteria of NACE [23] given in Table 3-3 are commented on in light of present knowledge. 

After each issue outlined in the evaluation criteria has been developed for each corrective measure, the selection of the most appropriate alternative can be made. Trade-offs among health risks, environmental effects and other pertinent technical, environmental and human health factors enter into this decisionmaking process. In the RCRA context, cost is not a factor in the selection process except when two or more corrective measure alternatives are determined by EPA to provide similarly adequate levels of protection of human health and the environment. 

However, after becoming familiar with site hazards as best as one can, along with analytical data, the level of protection shonld be reexamined. This reexamination shonld be bnilt into the plan, and specific criteria for downgrading levels of protection or the type of protective eqnipment shonld be considered. Even a downgrade in the type of coveralls reqnired can make a large difference in worker heat stress load. The ability of tyvek to breathe (as opposed to saranex) is very desirable when considering worker comfort and heat load. These options, and when they become viable, shonld be anticipated beforehand and placed in the SSAHP. 

The results of these experiments have been considered by the Joint Committee for the Co-ordination of the Cathodic Protection of Buried Structures and, in view of the various types of buried structures concerned and the circumstances in which field tests are conducted, the Committee decided not to amend its provisional recommendation that when cathodic protection is applied to a buried structure the maximum permissible potential change in the positive direction on a nearby pipe or cable should be 20 mV. If there is a history of corrosion on the unprotected installation no detectable positive change in structure/soil potential should be permitted. These criteria of interaction have been adopted in the British Standard Code of Practice for Cathodic Protection . 

Over the last 60 years criteria and methods based upon resuits of catastrophic events have been used for the design of expl facilities. The criteria and methods did not include a detailed or reliable quantitative basis for assessing the degree of protection afforded by the protective facility. Recentiy, extensive research and development programs have been undertaken to establish procedures which permit a more sound and scientifically based approach to current and future design requirements (Refs 1 to 9)... 

ERA Ambient water quality criteria for protection of human health for alpha-, beta-endosulfan and endosulfan sulfate water and organisms organisms only 110 pg/L 240 pg/L EPA 1999c... 

The sole objective of all hygiene and manufacturing controls is to ensure the quality of the pharmaceuhcal product for the safety and protection of the pahent. The manufacture of non-sterile pharmaceutical products requires that certain criteria of cleanliness, personal hygiene, produchon methods and storage must be met. Many such products are for oral and topical use and the question may fairly be posed as to the point of what are now quite stringent conditions. Nevertheless, some carefully controlled hospital studies have indeed shown that both types of medicine may be associated with nosocomial (hospital-acquired) infections and this risk can be minimized by the application of GMP principles. 

Ambient Water Quality Criteria for Protection of Human Health" Ingesting water and organisms EPA 1991... 

Wood CM, Adams WS, Ankley GT, DiBona DR, Luoma SN, Playle RC, Stubblefield WC, Bergman HL, Erickson HL, Dorward-King EJ. 1997. Environmental toxicology of metals. In Reassessment of metals criteria of aquatic life protection, Berman HL, Dorland-King DJ, editors. Pensacola (FL) SETAC, p. 31-51. 

As discussed in Chapter 4, some risk-based decision making can benefit by the development of tolerance criteria for the various types of risk to which building occupants may be exposed. When identified risks are higher than what can be deemed tolerable, they should be eliminated or reduced to control the company s risk exposure. The process of risk identification and evaluation, comparison to tolerance criteria, and elimination or reduction of intolerably high risk is known as risk management. Figure 6.1 illustrates this process. Application of these tolerance criteria helps protect building occupants and ensure that resources are appropriately applied. 

EPA OWRS Ambient Water Quality Criteria for Protection of Human Health Ambient Water Quality Criteria for Protection of Aquatic Organisms Freshwater 50 pg/L 45 FR 79318 EPA 1980d 50 FR 30784... 

Proposed mercury criteria for protection of various resources and human health... 

Proposed PAH criteria for protection of human health and aquatic life... 

Table 2.6 Proposed Chromium Criteria for Protection of Human Health and Natural Resources...

Table 5.11 Proposed Mercury Criteria for Protection of Various Resources and Human Health Resource and Criterion (units in parentheses) Mercury Concentration Reference11...

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