Fault analysis

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]. 

It should he accepted that fault analysis can he a slow process and that it usually defies prior estimates of the time it will take, regardless of the pressures of persons who are affected hy the interruption of the service. In any case, hasty decisions and random efforts to get the plant working again are to he shunned, since more damage may result. 

Corresponding to these facts, there is a differentiation in the so-called categories ia and ib for zone 0 and zone 1 applications. To comply with the special high degree safety requirements imperative for zone 0 areas, apparatus or electrical circuits are subject to a two-fault analysis. The i-standards define... 

For the minor degree of exposure to danger in zone 1, a single-fault analysis is considered adequate. 

Figure 6.197 One- and two-fault analysis applied to a voltage-limiting circuit.

As mentioned above, fault analysis is of central significance the number of (countable) faults determines the category of an apparatus. The correlation... 

The electrical parameters are current, voltage, internal resistance etc. which are specified as rated data for normal operation. These data shall not be confused with the safety-related maximum values which are the result of a fault analysis (theoretical maximum values) and which cannot occur in practice. These safety-related maximum values form the basis of planning in the field of intrinsic safety - i They may be concluded from the certificate. 

In addition, it may be mentioned as a special feature of intrinsically safe systems that a fault analysis (as an assessment for individual apparatus) (two faults are assumed for category ia, one fault for category ib) may be applied to the system as a total and not to each individual apparatus. 

C. CHILDS Fault Analysis Group, Department of Earth Sciences, University of Liverpool, Liverpool, 169 3BX, UK... 

Carry out a fault analysis of a 3-D fault map at top reservoir level. 

Table 8.2 Examples of the use of microscopy in textile production and fault analysis ...

Cut or ground cross-sections of fibres, yams and fabrics are of interest for fibre identification, in fault analysis in primary and secondary spinning and in checking the penetration of dyes into fibres, filaments, yams and fabrics. These methods are also used to investigate hollow and multicomponent fibres, the build-up, adhesion and evenness of coating layers and the analysis of other textile composites. AU of this can be useful for damage analysis. Grieve has written a review on cross-section preparation methods for fibres. 

N. R. Malhotra, Fault analysis in power systems Volume 1. Orient Longmans Ltd, Bombay, India (1969). 

Preventive maintenance refers to inspection, test and varied maintenance activities performed in the specified state of the devices so as to discover fault signs and to avoid fault occurrence. Reliability-Centered Maintenance (RCM) follows a basic thread performing a function and fault analysis of the devices, understanding the fault consequence... 

Product contamination leaking valves/crud left in storage tanks/crud left in dead legs in piping/corrosion products/unexpected chemical reactions/sampling fault/ analysis fault/unexpected solubility effects. 

Event analysis - including day-to-day fault analysis, HSE events, media events, customer complaints. 

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