Abstract:
A safety system receives inputs from safety related input devices such as smoke detectors and the like and provides triggering outputs to notification appliances such as bells and the like and/or safety functions such as door releases. To facilitate testing of the input devices the system incorporates a timer operative to disconnect the output devices for a period of time during which testing may be achieved, automatically reconnects the output devices at the end of the time, records the number of triggering outputs received at the outputs during that period.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of U.S. Provisional Application 61/554,714 filed Nov. 2, 2011, the contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention in general relates to safety systems for use in buildings which employ sensors for dangerous conditions to activate appropriate alarm devices and the like, and in particular to a safety system incorporating features which facilitate system installation, maintenance and testing and a method of operation of such a safety system. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention has utility in the installation, maintenance and testing of a safety system. Such systems are found throughout apartment buildings, commercial spaces, and industrial, institutional, health and educational settings and the like. Typical activating devices include such sensors as smoke detectors, heat detectors, manual pull stations, carbon monoxide detectors, radiation detectors, seismic sensors, and other hazardous gases or conditions that might occur in a given setting. 
         [0004]    Present, commercially available safety systems have multiple sensors that pass an activation signal to an alarm panel that uses the signal to activate an alarm or notification appliance such as a siren, bell, strobe light, or recorded instructions. Alternatively, or in conjunction with activation of notification appliances, the panel of a present system also activates responsive safety functions. Representative of these safety functions are door releases, smoke dampers, lock controls HVAC shutdowns, elevator recall, sprinkler systems, chemical fire suppression agents, or the like. 
         [0005]    During installation, maintenance and subsequent testing of a present safety system, each activating device is required to be tested from start to finish (“end to end”) to the satisfaction of safety authorities, typically local authority having jurisdiction, that a given activating device in fact activates each and every notification appliance and safety function the activating device is intended to operate. By way of example, if an internal door is released and closed by a safety function, the door must be opened before a smoke detector is tested. Upon testing the smoke detector, the installer must verify that the door closed in response to smoke detector activation. For each additional detector to be tested, the door must be reopened and verified to close again. If there are a substantial number of activating devices and/or a substantial number of safety functions, the number of testing combinations grows exponentially. 
         [0006]    Live testing of the proper operation of a present safety system by initiating a signal from a sensor and checking the activation of the appropriate notification device and/or safety function is often disturbing to occupants of the building housing the system and to avoid such disruptions during installation or testing installers or testers are motivated to use various short cuts and/or only test a select subset of the system or ignore this testing together—with or without a waiver. 
         [0007]    When an installer or tester of a present system fails to test all the possible combinations and permutations of a system, regardless of complexity, a waiver is required to be obtained from safety authorities, as abbreviated testing endangers the safety of structure occupants. Alternatively, an installer or tester of a system may disconnect and test portions of the system separately. This does not meet the requirements of many safety codes and doesn&#39;t verify the proper start to finish, end to end, operation of the system in all situations. Additionally, this abbreviated test regime includes the risk that the installer or tester may forget to reconnect the output devices or may make a mistake while reconnecting the activating devices and effectively change the functionality of the overall system and/or forget to remove all temporary “by-pass/cut-off” methods. To mitigate the risk of failure to reconnect activating and/or output devices or make a mistake during reconnection, installers and testers have developed a number of clever techniques to help assure that all devices are reconnected including color-coded labels and part counts. However, none of these workarounds to complete system testing is foolproof and indeed often not code compliant. 
         [0008]    Thus, there exists a need for a safety system that facilitates fail safe safety system installation maintenance and testing without undue disturbance of the building containing the system regardless of the complexity of the system. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is accordingly directed to a novel safety system including an installation, test and maintenance relay device that accepts one or more triggering inputs from activation devices, such as smoke detectors and like sensors, and provides them to a timing circuit that may be activated either manually or automatically to temporarily inhibit the relay device from providing outputs that energize one or more alarm signals such as bells, sirens, or the like, as well as from safety function devices such as door releases, smoke dampers, HVAC shutoff, and the like. 
         [0010]    This delay allows testing of the activation devices during installation, inspection, periodic maintenance, or troubleshooting without activating the alarm signals or safety function devices. After the time delay expires, the system automatically returns to normal operation, precluding an accidental inactivation of the system after conclusion of testing. It also provides an additional signal that the device is in the installation, maintenance and testing mode. 
         [0011]    During the test period, while the outputs to the notification and safety function devices are deactivated, the installation, testing and maintenance device records the number of triggering signals that are received from the system. This allows the person testing the system during the test period to generate a given number of alarm condition outputs from the inputs and check to see if the number of trigger signals received at the output device coincides with the number of signals sent to check the integrity of the circuit between those end to end points. 
         [0012]    To test a system employing the present invention, typically involves two steps. One, testing the operation of the alarm and safety function devices or some subset of these devices. This may be done during a time that the building is unoccupied to avoid disturbing the occupants. Second, actuating the timer and relay that disconnect the input generated signals from the alarm and safety function devices and generating alarm triggering signals from each of the inputs and counting the triggering signals that reach the maintenance mode relay to insure the integrity of the communication pathways between the inputs and the maintenance mode relay. This step may be performed while the building is occupied without disturbing the occupants. 
         [0013]    The present invention thus allows testing and validation of a system&#39;s safety functions and alarm or notification devices without disturbing the building&#39;s occupants. It additionally provides the tester with a positive feedback of the number of system requested activations that occurred during the test mode and verifies all pathways end to end. This number of “hits” can be further verified by the tester to account for every possible operational scenario that a tester activates, and optionally be documented for validation. The systems of the present invention can be hardwired, wireless and/or use a combination of signal transmission technologies. Systems, circuits and devices serviced by the present invention can range from a single one to any number. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention is further detailed with respect to the following exemplary drawings. These drawings are provided for illustrative purposes only. The invention is not intended to be limited to the specific embodiments depicted. 
           [0015]      FIG. 1  is a schematic of an inventive safety system; 
           [0016]      FIG. 2  is a schematic depicting relay blocks operative in an inventive safety system of  FIG. 1 ; and 
           [0017]      FIG. 3A-3I  are schematics of various signal conditioning blocks useful with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring now to  FIG. 1 , a schematic diagram of a preferred embodiment of the inventive system is generally indicated at  10 . This system includes one or more input devices  12  for sensing dangerous conditions. The input devices include at least one of the aforementioned activating devices such as smoke detectors, Co2 detectors and the like. The input devices normally operate to provide output signals which activate alarms and the like and safety devices (“output devices”) when they detect dangerous conditions indicative of a real emergency. This condition is designated  14 A on  FIG. 1 . The system may also be placed in a test or maintenance mode wherein the input devices are activated to generate alarm output signals without activating output devices to allow the testing of the operation of the system from the input to output ends. In  FIG. 1  this condition is designated  14 B. The signals generated by the input devices to the balance of the system during normal, live operation, wherein an output signal is generated upon detection of a dangerous condition, are designated  16 A. The signal path for the signals generated by the input device during a test or maintenance stimulus are designated  16 B. 
         [0019]    In either of these live or test modes the output signals from the input devices are communicated to an alarm panel  15 . The signal paths from the input devices to the alarm panel, like the other communication paths in the system, may be hard wired, or generated wirelessly by radio, infrared signals or the like. 
         [0020]    The alarm panel  14  accepts the signals from the input devices generated in either mode and generates outputs that are intended, during the normal mode operation to activate selected notification devices or safety devices. By way of example, an alarm signal generated by a smoke detector may be required to activate an alarm bell and open smoke dampers. Therefore, the input to the alarm panel  14  of an alarm signal from smoke detector will generate output signals from the panel which, in live operation of this system  10 , will activate the alarm bells and open the smoke dampers. 
         [0021]    The alarm panel may use separate wired circuits to activate the required output for each input device or may constitute a more flexible microprocessor based device. It will typically provide several output signals for each sensor signal it receives. These signals are provided to an installation, testing and maintenance relay  18  which is subsequently described in  FIG. 2 . As will be subsequently disclosed in detail, the maintenance relay may be used by personnel testing the operation of the system in accordance with the mode illustrated at  14 B, without generating alarm outputs that would disturb occupants of the building in which the safety system is installed. It thus inhibits signals originating from the input devices, and translated by the alarm panel, from actuating the notification devices, such as the alarm bell  20  or the audio warning system illustrated by the speaker  22 , or the safety devices  24 . During live operation of the system the maintenance relay generates output signals in signal path  16 A to the notification devices or the safety devices when triggered by the emergency signal from an input device relayed through the alarm panel  14 . 
         [0022]    This allows the system  10  to be tested by generating signals from the input devices to activate the notification devices  20  and  22  and the safety devices  24  when the maintenance relay  18  has not been set into the test mode, preferably when the building in which the system is installed is unoccupied. If the notification devices and safety devices operate properly, the balance of the system may be tested by initiating a time delay in a manner which will be subsequently described. 
         [0023]    While the maintenance relay  18  is in the test mode, the various input devices  12  are actuated to generate signals that are translated by the alarm panel  15  into signals for the output devices, but these are inhibited by the maintenance relay. In this mode the tester needs to verify that the number triggering signals reaching the output devices coincides with the number of signals generated by the input device under test. 
         [0024]    To enable this, the maintenance relay sends signals based on each triggering inputs it receives to a unit  48  which records these emergency activation signals received by the maintenance relay during testing. By way of example if a person testing this system during a time delay generated by the maintenance relay  18  causes a smoke detector to generate output signals three times during a test, the tester will check the record in the unit  48  to ensure that three trigger signals were received during that delay period. Alternatively, the unit  48  could be in communication with the tester through a personal wireless audio device or the like so that each time an emergency signal is generated by an input device the tester could ensure that a signal was received by the maintenance relay  18 . 
         [0025]      FIG. 2  is a schematic diagram of the structure of the maintenance relay  18 . It receives inputs on a signal path  16 A/ 16 B from the alarm panel  15 . This signal path is designated as a signal line but it could be a multiconductor bundle of all of the possible outputs of the alarm panel  15  which are ultimately directed toward the notification devices and the safety devices. If it is a single conductor it may carry digital signals designating the notification devices or safety devices to be energized. Optionally these installation, maintenance and testing operations could be documented and/or archived (dated/timed) to create a permanent record of the testing. 
         [0026]    The input signal is directed to a detector device  30  which detects a signal or a “hit” from the alarm panel  15  generated by a signal from one of the input devices  12 . During the test/maintenance mode of the system these signals are sent to a recorder  48  which records the emergency activation requests received during testing. The testing mode is initiated by a timer  32  which may be actuated manually as by a push button  34 , or initiated by remote signal from the test operator or an offsite location. The relay  18  may include a dial such as  36  for controlling the length of the time delay signal generated by the timer  32 . 
         [0027]    During the timing period, a signal light  38  may be energized to indicate to operators that the device is in timing mode. In the timing mode, the timer opens where a schematically illustrated as a single pull switch  40  which interrupts the passage of signals from the output of the alarm panel to the notification devices and safety devices. The input signal constitutes a bundle of conductors, the switch  40  would be required to open all of the conductors. Alternatively, a single pulse switch  40  could be implemented with a semiconductor device or the signal path involving either a single conductor or multiple conductors could be interrupted by grounding the conductors rather than by physically interrupting them. 
         [0028]    At the end of the time delay the system automatically returns to its normal status without requiring intervention by personnel. Similarly, in the event of relay  18  failure the system would return to the non-maintenance mode rendering it fail safe. This eliminates the possibility of a tester forgetting to return the system to its normal status at the end of the testing routine. 
         [0029]    The signals generated by the input devices operating through the alarm panel  15  may not have the proper electrical format to energize the notification devices or the safety devices. Accordingly, it may be necessary to pass the output signals from the alarm panel through a signal conditioning device by way of example, the signal condition device may vary in voltage, polarity or wave form of the signals provided to the notification devices and safety devices. 
         [0030]    These signal conditioning devices could be provided at each of the notification devices and safety devices themselves, thus, signals and the path  16 A from the maintenance relay  18  during normal operation of the system can first pass through a signal conditioning device associated with each notification device or safety devices. Alternatively, the signal conditioning devices could be built into the maintenance relay  18  or the outputs of the alarm panel  15 . 
         [0031]      FIGS. 3A-3I  depict typical forms of single conditioning blocks for the input voltage. 
         [0032]      FIG. 3A  shows a polarized signal conditioning block at  26 A. The block  3 A includes a diode that only responds to direct current voltages applied with a correct polarity. 
         [0033]      FIG. 3B  depicts a bridge signal conditioning block at  26 B and is particularly well suited to receive a trigger input that is either alternating current or direct current and of any polarity. 
         [0034]      FIG. 3C  depicts a voltage regulator signal conditioning block at  26 C. The block  3 C moderates voltage of a trigger input typically downward to a lower voltage so as to feed a relay coil at a constant voltage thereby facilitating usage of a larger range of input voltages associated with trigger input  5 . 
         [0035]      FIG. 3D  shows a resistive voltage reduction signal conditioning block at  26 D. 
         [0036]    A capacitive voltage reduction signal conditioning block is shown at  26 E in  FIG. 3E . A common attribute of voltage reduction signal conditioning blocks  26 D and  26 E is that a trigger input with a high voltage is reduced to a lower voltage better suited for driving a relay coil. 
         [0037]      FIG. 3E  depicts a capacitive signal conditioning block at  26 E with a capacitor across the trigger input holding the block in a closed circuit condition even if power is momentarily disrupted. 
         [0038]      FIG. 3F  depicts a low current signal conditioning block at  26 F. The block  26 F allows a trigger input to drive a transistor or similar circuit that in turn powers a relay coil. 
         [0039]    Block  26  is particularly well suited to allow a low current or low voltage trigger input to control a comparatively higher current or higher voltage output. It is appreciated that an external power source is required in a low current circuit of  26 G so as to boost the output in terms of current and/or voltage relative to the trigger input. 
         [0040]      FIG. 3H  depicts an indicator signal conditioning block at  26 H in which a light emitting diode (LED) or similar signaling device is wired across the trigger input to indicate activation of an activating device. The indicator signal conditioning block  3 H is particularly well suited to aid in troubleshooting of a system  10 . 
         [0041]      FIG. 3I  depicts a control signal conditioning block at  26 I. The block  3 I includes a switch to provide for local control. As a result, the block  24   j  can be forced into an on position, off position, or into electrical communication with a trigger input. 
         [0042]    The various signal conditioning block functionalities  26 A- 26 I are readily combined to create additional functionality. Further, it is appreciated that signal conditioning block  26  is readily operated under microprocessor control to provide still additional functionalities such as timers, remote monitoring, and dynamic configurations.