Alarm systems performance indicator

All critical instruments/systems, alarms and performance indicators must be maintained in accordance with established preventative maintenance procedures. Consider specialized preventative procedures for activities within this band... 

Results presented in Table 4 indicate contribution of each PSF to the overall likelihood of success for the task imder consideration. In the task 2 the dominant PSF is availability of established procedures (43% of the SLI) necessary to successful performing given task. This information can be useful for cost benefit analyses in terms of required modifications to be designed in HMI within alarm system in order to provide better awareness of situation by the operator and to mitigate the prohahihty of erroneous action committed hy the operator. 

Major focus on an alarm system life cycle Similarity in life cycle development with lEC 61511 lEC 62682 developed based on this standard Performance indicators are very clearly defined Section on compliance... 

A high alarm rate can be indicative of poor control system performance (see Section 10.2). Operator logbooks and maintenance records are valuable sources of information, especially if this information has been captured in a computer database. 

In the application of the single failure criterion, the detectability of failures is implicitly assumed. However, there may be failures which are not detected by testing or revealed by alarms or anomalous indications. The systems should be analysed for such undetected failures. The preferred course would be to redesign the system or the test schones to make the failures easily detectable. If this is not possible, it should be assumed that such undetected failures have occurred and then a single failure should be assumed in addition. It should be ensured that safety functions can be performed under these circumstances. 

Column temperature alarm Not a complete indication at this stage. It may be a spurious alarm Cross-examine related indicators Data collection Can operator acquire irrelevant or insufficient data Can operator fail to crosscheck for spurious indications Identification/lnterpretation Can operator fail to consider all possible system states and causes of problem Can operator fail to perform a correct evaluation Can operator fixate on the wrong cause Goal Selection Can operator fail to consider possible side-effects Can operator fail to consider alternative goals Can operator fixate on the wrong goal ... 

Hardware requirements — The system controller responsible for synchronizing the events is defined as LC System 1. It requires at least two time event outputs to trigger the injection of LC System 2 and start MS data collection. If MS fails, the injection of LC System 1 should be inhibited. Autosampler with ready-in, alarm-in, and stop inputs indicate capability to be stopped remotely. The autosampler of LC System 2 must be able to prepare a sample before the run from LC System 1 is finished and hold the sample in the injector loop until an injection signal is received. A manual injection input devices indicates that the autosampler can perform the required function. 

Where the need for fire detection is identified, the required performance of the fire detection system is already specified as part of the grading process. Fixed fire detection is typically installed to protect equipment that is high value, long lead time, or likely to be significant fire escalation hazards. The performance specification defines fire size and response time thresholds for alarm and action(s). Fire hazards are defined by radiant heat output (RHO). RHO gives a reasonable indication of the potential damage and the probability that the fire will escalate or cause loss. The RHO should not be used to determine fire thermal loading onto equipment and structures. Table 8-3 compares RHO and flame area for some typical hydrocarbon fires. 

Instrumentation and Control Controllers reduce the problems associated with operational errors and maintain process conditions for optimum performance. An evaporator must be instrumented adequately to provide the data necessary for evaluating the system s performance end to provide indicators for identifying problems affecting thermal efficiencies. Pressure, temperature, and flow indicators and possibly alarms must be incorporated at critical areas, such the first-stage condensate discharge line and evaporator vapor lines. 

FGS functionally performs a number of functions such as monitoring of fire, smoke, and/or sensing accumulation of gas. On detection generates alarms and initiates mitigating actions. It consists of sensors, logic solvers, and final elements to initiate mitigating actions. Additionally, it also interfaces with other systems in IPS and SIS. Within the system, it diagnoses the fault of sensors, etc., and at times inhibits the same or supports manual inhibition with alarm in each case. As stated earlier, philosophy documents lists out quantity of various types of FGS sensors at various locations in a tabular form with various facility areas as rows. The columns indicate various types of detectors such as ... 

The specific requirements for dc power system monitoring derive from generic requirements embodied in IEEE Std. 308 and in RG 1.47. In summary, these general requirements state that the dc system (batteries, distribution systems, and chargers) shall be monitored to the extent that it is shown to be ready to perform its intended function. Accordingly, the NRC staff has used the following guidelines for the indications and alarms to be provided in the main control room for each Class IE dc system ... 

In the past these functions were performed by panel boards consisting of indicators, alarms, strip-chart recorders, and single-loop controllers. Today, distributed control systems (DCS) and data historians perform these functions (see Section 12.4.6). 

Most of the chemical fume hoods considered here consist of a cabinet or enclosure set at waist level (above a table or storage cabinet) that is connected to a blower located above the hood or external to the hood through a duct system. The cabinet has an open side (or sides) to 2illow a user to perform work within. A movable transparent sash separates the user from the work. Most chemical fume hoods have a sill that functions as an airfoil at the work surface below the sash. The connection to the blower might be by use of a v-belt, or it may be direct drive. This allows provision of a smooth flow of air with minimal turbulence. In some installations, axially mounted blowers are used, especially if multiple hoods are ducted into a common blower. Baffles located in the rear of the cabinet provide control of the air flow patterns, and can usually be adjusted to provide the best air flow around the experiment or procedure being performed. Many chemical fume hoods are equipped with air flow indicators, low flow monitors and alarms, and differenti2d pressure sensors to allow the user to operate safely. The major types of chemical fume hoods include the standard/conventional, W2dk-in, bypass, variable air volume, auxiliary air, or ductless types. Additional types include snorkels and canopies that are portable. Each type must be understood to be operated most efficiently within specifications (see the section below on safe operation). 

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