Visual Alarm Signaling

An exterior intrusion sensor is a detection device that is used in an outdoor environment to detect intrusions into a protected area. These devices are designed to detect an intruder and then communicate an alarm signal to an alarm system. The alarm system can respond to the intrusion in many different ways, such as by triggering an audible or visual alarm signal, or by sending an electronic signal to a central monitoring location that notifies security personnel of the intrusion. 

An annunciator responds to the detection of an event by emitting a signal. This signal may be visual, audible, electronic, or a combination of these three. For example, fire alarm signals will always be connected to audible annunciators, whereas intrusion alarms may not be. 

The malfunction audible signal should be capable of being silenced after operation of an acknowledgment "trouble alarm silence" switch. The visual trouble signal should remain illuminated. 

Each detection circuit should be shown in trouble condition by a separate visual signal. One audible trouble alarm signal may be used for more than one circuit. 

One very sueeessful measure we took was to run part of the software system test suite in the same environment as its expected final use. Hence, it proved to be an intelligent idea since we discovered many defects we would not have discovered until the instrument would have been in the field. This was because another factor to consider is the environment where the device is used, e.g. if the user works in an extremely noisy environment, then the effect of risk mitigations based on audible signals and alarms may be altered or invalidated. The same applies to visual alarms when the user is operating with other devices at the same time and not paying attention to the computer screen. Note also, as eommented before, that users may interfere with the expected use. Indeed, the noisiest alarm that mitigates a safety eritieal situation may become useless if the user turns off the computer... 

Audio and visual alarm indicators. Interlace for network connections. Additional compound detection can be programmed. Multicompound detection capability according to specific signal detector used. The MINICAMS is a proven technology capable of monitoring to sub-AEL chemical-agent concentration in the air. 

A continuous gas detection system must be provided to detect the presence of hazardous (toxic or highly toxic) gases at or below the permissible exposure limit (PEL) orthe ceiling limit (see UFC 8003.3.1.6). The detection system must initiate a local audible and visual alarm as well as transmit a signal to a constantly attended plant Emergency Control Station (ECS). Activation of the alarm/monitoring system must automatically close the shutoff valve on highly toxic or toxic gas supply lines. 

Visual alarm systems - visual alarm systems (beacons) are used to supplement audible warning signals in situations where an audible system is likely to be ineffective, for example where the ambient noise levels in the building would make it difficult to hear an audible signal. Beacons must be provided where ambient noise levels exceed 90 dB(A), or in areas where hearing protection is worn or people with hearing impairments may be present. 

If the occupants of a building have impaired hearing it may be appropriate to provide visual alarm systems in the areas occupied by those people. This should include any toilets and welfare facilities. If people with impaired hearing sleep in the building it may be appropriate to provide tactile devices linked to visual alarm devices. These devices may, for example, be placed under pillows and wired into the fire alarm circuits or be triggered by radio signals. 

Continuous monitors usuaUy indicate the pollutant concentration on both an indicator and a chart recording. This provides a visual indication of the instantaneous emissions, along with a permanent record of the quantitative emissions over a period of time. The monitoring system may also be equipped with an alarm device to signal the operator if the allowable emission level is being exceeded. Data-logging systems coupled with micropro-... 

An alarm system consists of sensors that detect different types of events an arming station that is used to turn the system on and off a control panel that receives information, processes it, and transmits the alarm and an annunciator that generates a visual and/or audible response to the alarm. When a sensor is tripped it sends a signal to a control panel, which triggers a visual or audible alarm and/or notifies a central monitoring station. A more complete description of each of the components of an alarm system is provided below. 

FIGURE 2.5 Visual signal is combined with odor release when an alarmed pronghorn Antilocapra americana) flares his "rump patch of long hair covering the ischiadic gland. (Photograph D. Miiller-Schwarze.)... 

The analysis is completed by a colorimeter that electronically compares the color intensity of the analytical stream against an air reference. The ratio signal is sent to a strip chart recorder and to a counter and logic card. Activation of visual and audible alarms will occur if predetermined agent levels exist. 

The nonportable instruments are set at fixed locations to detect the radiation field they are usually equipped with an alarm that will provide an audio and/or visual signal when the field intensity exceeds a preset limit. Examples are continuous air monitors and personnel monitors (e.g., hand, foot, and whole body). A list of several health physics instruments and their characteristics is given in Table 16.11. 

In particular, the therapy of severely ill patients with deficiencies of one or several vital systems is based on the surveillance of the important body functions. In addition, the correct function of the medical equipment used and the connections to the patient need to be monitored because a malfunction of devices assisting vital body functions may be fatal for the patient. During intensive care, for continuously monitored parameters automatic alarm systems are used which signal a deviation from preset alarm limits by visual and/or audible alarms and which automatically start a recorder to record selected parameters during the alarm situation. 

Typically means an anditory alarm (e.g., siren) or visual indication (e.g., flashing lights) to warn of a hazard aspect occurring over a wide area (e.g., toxic gas release in a chemical plant tsnnami approach, etc.) and the need for immediate actions to prevent injury or damage (e.g., evacuation, shelter-in-place, etc.). The effectiveness of the signal is dependent on its capability to be observed, the population s awareness of the signal characteristics, and the actions to be taken upon its activation. 

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