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Intrinsic safety testing

Intrinsic Safety. Static electrical concepts such as minimum ignition energy do not directly apply when assessing the safety of electrical circuits such as radios, flashlights and instmmentation. Intrinsically safe electrical equipment is usually available which has been subjected to fault analysis and testing. The equipment must be certified for the flammable atmosphere in which it will be used (NFPA 497). Refer to texts on Intrinsic Safety such as [63]. [Pg.5]

Under the Medical Device Amendments of 1976, the FDA is responsible for premarket evaluation of all laboratory testing devices (in vitro diagnostics) intended to be commercially marketed in the United States. There are two major pathways for introducing a medical device into the marketplace the premarket notification [510(k) clearance] and the premarket approval (PMA). The purpose of the 510(k) is to establish that a device is substantially equivalent (SE) to a legally marketed (predicate) device. The purpose of the PMA evaluation process is to establish the intrinsic safety and effectiveness of a new device. Unless specifically exempt, a sponsor must have an approved PMA or cleared premarket notification [510(k)] by the FDA before a device may be legally marketed for IVD use (Fig. 1). [Pg.59]

Again and again, testing houses, manufacturers and users of intrinsically safe products have put the question, how could the narrow borderlines of classic intrinsic safety concerning available power be passed over These borderlines are determined by reference curves as well as by installation rules. The following approaches are dealt with in more detail below ... [Pg.403]

The standards for intrinsic safety - i EN 50020 and IEC 60079-11, define the scope of type verifications and tests as well as routine verifications and tests (in clauses 10 and 11). Among the type tests ... [Pg.450]

Intrinsic safety ia, ib, ic (note 2) EN 60079- 11 The equipment used in the explosion hazard zone only contains intrinsically safe circuits. A circuit is intrinsically safe if neither a spark nor a thermal effect can cause the ignition of a standard explosible atmosphere. The corresponding tests are carried out under standardized conditions, which comprise both normal operation and certain faulty states. Measurement and control devices, communication devices, sensors, actors... [Pg.181]

Establishing a procurement policy, which includes a pre-procurement risk assessment, will ensure that correct selection of plant and equipment for use in hazardous areas (where a flammable or explosive atmosphere has the potential to cause a fire or explosion) will minimise the risk relating to such equipment. BS EN 50020 2002, Electrical apparatus for potentially explosive atmospheres - Intrinsic safety i , specifies the construction and testing of intrinsically safe apparatus, intended for use in potentially explosive atmospheres and for associated apparatus, which is intended for connection to intrinsically safe circuits which enter such atmospheres. This document may well form the basis from which an organisation establishes its procurement policy for such equipment. [Pg.158]

Because of Che distance between the various elements of the loops, interface racks and control room, the use of portable phones f< two-way communication during testing is essential. This, of course, is subject to intrinsic safety and interference requirements, especially with regard to corruption of computer memory. [Pg.42]

The accident at the Three Mile Island (TMI) plant in Pennsylvania in 1979 led to many safety and environmental improvements (4—6). No harm from radiation resulted to TMI workers, to the pubHc, or to the environment (7,8), although the accident caused the loss of a 2 x 10 investment. The accident at the Chernobyl plant in the Ukraine in 1986, on the other hand, caused the deaths of 31 workers from high doses of radiation, increased the chance of cancer later in life for thousands of people, and led to radioactive contamination of large areas. This latter accident was unique to Soviet-sponsored nuclear power. The Soviet-designed Chemobyl-type reactors did not have the intrinsic protection against a mnaway power excursion that is requited in the test of the world, not was there a containment building (9—11). [Pg.235]

There are two aspects of this program that will effect the research and development investment decision. First, the costs of premanufacture notification (including testing costs) will increase the investment in R D necessary to develop and market new chemicals. The health and safety properties of a chemical must now be considered an intrinsic part of the new chemical development process, right alongside consideration of the substances commercial properties. Both are equal parts of the "total product". Tb the extent that this results in increased testing for health and environmental effects, the amount of investment required to achieve a given level of output from R D will also rise. [Pg.169]

The major advantage of (fractional) oral clearance as a phenotypic trait is that its value is linearly related to the enzyme s catalytic activity, provided that first-order conditions are present. This requirement, along with any safety considerations, is the main reason the dose of an in vivo probe should be as low as possible, consistent with analytical considerations. Furthermore, it is possible to directly extrapolate this type of trait measure to the disposition of other drugs whose metabolism is mediated by the measured enzyme and also to place the trait value within a therapeutic context. On the other hand, estimation of oral clearance requires multiple blood and urine collections, often over many hours, that are an inconvenience for the study subject and require considerable amounts of analytical time and effort. Because of this, simpler and less time-consuming approaches have often been used. However, it is not always appreciated that such phenotyping tests provide only an indirect measure of metabolizing activity and may be affected by factors other than the enzyme s intrinsic clearance. In addition, it is difficult to relate an indirect trait measure to parameters that are of clinical importance, such as the drug s clearance. [Pg.585]

Radex Safety Calorimeter. The Radex calorimeter is a modular instrument that can simultaneously evaluate six different samples (size range 0.5 to 5 ml), or one substance under a variety of conditions. Each module is a separate entity with its own calibrated oven capable of being operated under an open, closed, or pressurized condition, with all temperature differences between the sample and the oven being stored in a microprocessor for further analysis. The Radex calorimeter is very versatile samples can be tested in either an isothermal or ramp mode. In the isothermal mode, each oven is heated to a preset temperature and held at that temperature throughout the experiment. In the ramp mode of operation, the oven is heated linearly to a preset temperature, or can be maintained at a given temperature for a predetermined time. The flexibility of oven function in the Radex calorimeter enables the user to determine the intrinsic stability of a chemical and to also compare the impact of such parameters as temperature, atmosphere, and impurities on the stability of a given substance. [Pg.68]

The toxicological evaluations related to human safety of chemical substances are a very complex process involving the determination of the intrinsic toxicity and hazard of the test chemicals. Subsequently, this evaluation leads to determining and establishing a no observed effect level (NOEL) the highest dose level tested experimentally that did not produce any adverse effects. This dose level then is divided by a safety factor to establish an acceptable daily intake (ADI) of the candidate chemical substance. The ADI value is normally based on current research and... [Pg.20]

However, none of these statutes were so directly focused on the chemical industry as the 1976 Toxic Substances Control Act (TSCA) in the United States and the Sixth Amendment to the Dangerous Substances Directive enacted by the European Parliament in 1979. These statutes did not focus on the industry s wastes, pollution or occupational exposures as much as on the intrinsic hazards - the toxicity, chemical stability, and bioavailability - of the industry s chemical products as they were used in commerce. These laws were intended to provide government agencies with the authority to collect relevant health and safety data on chemical products, require testing where data were missing, and condition and restrict the use of chemical substances so as to reduce unreasonable risks to the public and environment. [Pg.53]


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See also in sourсe #XX -- [ Pg.326 ]




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