Limits of alarm

Agent Alarm Limit of Alarm (mg/m ) Response Time (s) Recovery Time (s)... 

LOA limit of alarm LOD Limit of Detection LOQ Limit of Quantitation LSE liquid solvent extraction MPA Methylphosphonic acid MDEA N-methyldiethanolamine MS Mass Spectrometry MS-MS Tandem Mass Spectrometry MTBSTFA N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide... 

Predictive maintenance systems use two methods of detecting a change in the operating condition of plant equipment static and dynamic. Static alert and alarm limits are pre-selected thresholds that are downloaded into the microprocessor. If the measurement parameters exceed the pre-set limit, an alarm is displayed. This... 

II = 80% constitutes the 80% limit of LEL, which is taken into account by explosimeters and some automatic atmospheric monitors in order to define the alarm zone of an environment likely to become explosive. 

Natural gas detectors should reliably detect the presence of gas concentrations far below the lower explosion limit of about 5% vol. In Germany many different cheap gas alarm systems can be purchased in DIY-market, but most of these devices are not based on any quality standard. Although high priced alarm and monitoring systems are available there is a lack of low cost reliable gas alarm systems for use in households which are based on appropriate standards. 

Identification, Materials of Alarms Adequacy, Limits, Fire, Fumes... 

Have operators been trained on the correct response to alarms and conditions that exceed the operating limits of the system ... 

Process excursions that reach or exceed the specified safety or quality limits of the process are important near misses that should be reported. However, the employees may not know that reaching the high-high pressure alarm point or reaching the rupture disk set pressure constituted a near miss. They checked the system to make sure the disk was intact, made sure the pressure returned to normal, and then continued operating. These may have been the warning symptoms of a pending major chemical process incident. 

D3 To what extent should plant be shut down for any deviation beyond the operating limits Does this require the installation of alarm and/or trip Should the plant be partitioned differently How is plant restarted ( 9.6)... 

This time factor must be estimated for the effective design of safety measures and compared with the Time to Maximum Rate (TMRld), giving the upper limit of the time frame. In fact, by applying Van t Hoff rule, the reaction rate doubles for a temperature increase of 10 K. If a temperature alarm is typically set at 10 K... 

Unless some discipline is imposed, engineering personnel, especially where contractors are involved, will define far more alarms than plant operations require. This situation may be addressed by simply setting the alarm limits to values such that the alarms never occur. However, changes in alarms and alarm limits are changes from the erspective of the process safety management regulations. It is pru-ent to impose the necessary discipline to avoid an excessive number of alarms. Potential guidelines are as follows ... 

Agent Alarm Limit of detection Response time Recovery time... 

Although we hope that preventive policies would preclude the need for this kind of alarm system, it is possible that some communities may be moving toward unacceptable limits faster than controls can be imposed. 

Automated system contribution to loss prevention is high however, one must understand the limits of this equipment, its power source, its failure mode (open, closed, on, off, etc.), whether an alarm is registered at the point of the upset (possibly in a location where no one would see or hear it), or at a computer screen occupied 24 hr of the day. ... 

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