Alarm initiation

Alarms should be initialed by the local or main control facility for the location. Manual activation means should be provided for all emergency, fire, and toxic vapor alarm signals. Activation of fire suppression systems by automatic means should also indicate a facility alarm. Most fire and gas detection systems are also set to automatically activate alarms after confirmation and set points have been reached. Manual activation of field or plant alarm stations should activate the process or facility alarms. 

Alarm activation points should be clearly highlight and marked. Their operation should be simple, direct and consistent throughout the facility or company, especially if personnel may be transferred or rotated from one location to another. 

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The CWS also studied the critical need for chemical agent detectors and alarms. Initially, World War I soldiers relied on their own senses (smell, and throat and nose irritation) to detect chemicals. Eventually, the CWS was able to produce various dyes that changed color when contaminated with mustard agent. Most of the formulas for the detector paints, however, were British, and the CWS had trouble duplicating their work.35... 

Estimates of Minimum and Maximum Response Times for Each Stage of Alarm-Initiated Activity in Simulated Emergencies... 

Stanton, N.A. and Baber, C. (1995). Alarm initiated activities an analysis of alarm handling by operators using text-based alarm systems in supervisory control systems. Ergonomics, 38, 2414-2431. 

If you were the RO on duty when the evacuation alarm initiated ... 

Control actions, e.g., provide alarms to indicate things getting out of control define control actions to get back into control. The HAZOP study is not complete until response to actions has been documented. Initial HAZOP planning should establish the management follow-up procedure that will be used. 

Endurance Burn Under certain cou(itious, a successfully arrested flame may stabilize on the unprotected side of an arrester element. Should this condition not be corrected, the flame will eventually penetrate the arrester as the channels become hot. An endurance burn time can be determined by testing, which specifies that the arrester has withstood a stabilized flame without penetration for a given period. The test should address either the actual or worst-case geometry, since heat transfer to the element will depend on whether the flame stabilizes on the top, bottom, or horizontal face. In general, the endurance burn time identified by test should not be regarded as an accurate measure of the time available to take remedial action, since test conditions will not necessarily approximate the worst possible practical case. Temperature sensors may be incorporated at the arrester to indicate a stabilized flame condition and either alarm or initiate appropriate action, such as valve closure. 

During testing, all alarm and shutdown funetions must be simulated to verify proper operation of the annuneiator display. The test teehni-eian must plaee his initials next to the tabulated set points as verifi-eation of eompletion. 

Before mining on tlie seal gas and lube oil pumps, initiate power to the eontrol panel to eonfirm tlie indieator lights are funetioning. At tliis time, there is no seal gas or lube oil pressure so tlie low lube oil alarm, low lube oil pressure shutdown, and seal gas alarm light should be on. 

Annunciator panels should be in a central location with alarm annunciators and shutdown annunciators grouped separately. The first alarm and the first shut-down normally sound a horn and are annunciated. This is called first-out indication. Subsequent shutdown or alarm signals received by the panel are either not annunciated or are annunciated in a different manner so that the operator can determine the initiating cause of the process upset. 

At the time that the alarm occurred, the worker was helping a colleague to fix a problem on an adjacent panel. The initiating event was therefore a distraction from another person (see Figure 2.15). 

Cancel initial weight alarm and remain at controls... 

Check tanker while filling Check omitted (Cl) Tanker not monitored while filling On initial weight alarm Alarm will alert operator if correctly set. Equipment fault, e g.,leaks not detected early and remedial action delayed... 

Cancel final weight alarm Operation omitted (08) Final weight alarm taken as initial weight alarm No recovery Tanker overfills... 

Cancel final weight alarm Note differences between the sound of the two alarms in checklist Alert operators during training about differences in sounds of alarms Use completely different tones for initial and final weight alarms... 

Failure to initiate action within 2 minutes of alarm —Wrong pair of switches chosen... 

CR Yellow Alert Gas leak in MSM Audible alarm, yellow flashing light on fire gas panel Uncertain could be real 1. Accept alarm 2. Cz area technician 3. Make PA announcement 4. Determine which gas detector is in alarm (its location) Suspend current operation. Scan panels for flashing yellow or red light. Turn around to MSM Fire Gas panel. Press "accept" button CCR Layout MSM Fire Gas panel Visual and audible Whatever op is doing when alarm occurs Initially disorientating because MSM does not have its own sound source. Alarm could be missed if second simultaneous alarm occurs on main bank of Fire Gas panels... 

A uniform definition of a failure and a method of classifying failures is essential if data from different sources are to be compared. The anatomy of a failure includes the initiating or root cause of a failure that is propagated by contributory causes and results in a failure mode—the effect by which a failure occurs or is observed. Modes include failure to operate, no output, failure to alarm on demand. The end result of a failure sequence is the failure effect, such as no fluid is pumped to the absorber, or a tank overflows. As discussed in Appendix A of IEEE Std. 500-1984, only the equipment failure mode is relevant for data that are needed in a CPQRA. The failure model used in this book is based upon those in the IEEE publication and IPRDS. ... 

However, the American consumer now seems ready to accept some reduction in cosmetic standards, provided pesticide use is diminished (47). Their concern about pesticide use is confirmed by the growing popularity of organic food stores and supermarkets that guarantee pesticide-free produce (48). Also, the "Big Green" initiative in California, although it didn t pass, signals that consumers are alarmed about pesticide use and are willing to take political action to make their views known. 

In a defensive strategy that is based on the detection of a chemical/biological agent in order to initiate a response, the time required for authorities to respond to an attack has three components the inherent response time of the detection system, the time required to verify the validity of a detector alarm, and the time required to decide on what action to take in response to the alarm. These three elements are discussed in more detail below. 

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