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<title>TC Life Safety: Blog Posts</title>
<link>http://www.totalcomputing.net</link>
<pubDate>2012-05-17</pubDate>
<description>List of Latest Blog Posts at TC Life Safety</description>
<language>en-us</language>
<isc:store_name><![CDATA[TC Life Safety]]></isc:store_name>
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<title><![CDATA[Discussion on Utilitizing VOIP as a Means of Transmitting a Fire Alarm Signal]]></title>
<link>http://www.totalcomputing.net/Discussion-on-Utilitizing-VOIP-as-a-Means-of-Transmitting-a-Fire-Alarm-Signal_b_10.html</link>
<pubDate>2012-04-12</pubDate>
<description><![CDATA[ Question: Looking to generate discussion on utilizing VOIP as a means of transmitting a fire alarm signal in lieu of POTS. Please share your positive or negative experiences. ]]></description>
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<content:encoded><![CDATA[Question: Looking to generate discussion on utilizing VOIP as a means of transmitting a fire alarm signal in lieu of POTS. Please share your positive or negative experiences.]]></content:encoded>
<isc:description><![CDATA[From the NFPA discussion group on LinkedInQuestion: Looking to generate discussion on utilizing VOIP as a means of transmitting a fire alarm signal in lieu of POTS. Please share your positive or negative experiences.Answer: I have several problems with VOIP that, in my mind make it unsuitable for emergency communications.First, there is no presently no way to monitor the ISP's transmission path to a receiving point except to send frequent testing polls with response return verifications, as is done with some mesh and GSM solutions. To the best of my knowledge, there are no UL/FM means to accomplish such verifications, from either the transmission or receiving points of a VOIP-based reporting system.My second concern is that in today's world, it is abundantly clear that among us, there are large numbers of capable people with very bad intentions, and said people can create havoc from great distances. In a scenario where VOIP is used at a receiving station, be it a fire department or central station, a simple Denial of Service attack on a receiving station's server[s] could be the first step in a [series of] man-made &quot;disasters.&quot;Last but not least, there is no transmission or encryption system that can't be hacked by anyone with the appropriate skill and motivation. If the DOD, NSA, and other &quot;high security&quot; government operations [with unlimited funding] can't keep the bad guys out, what chance does a standard, commercial operator have?I understand that we will always have to rely on less than perfect systems, but at this point, VOIP is the least perfect and least reliable method of transmission available to our industry. Unless or until VOIP manages to leap frog over the competing paths [POTS, GSM, Mesh] with respect to reliability and surviveability, then it remains unsuitable for the intended use, i.e. fire and emergency signalling.Mike Agri - Engineered SystemsTC Life Safety]]></isc:description>
<isc:productid><![CDATA[10]]></isc:productid>
<isc:author><![CDATA[Administrator]]></isc:author>
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<title><![CDATA[Purpose of Listing Fire Alarm Components]]></title>
<link>http://www.totalcomputing.net/Purpose-of-Listing-Fire-Alarm-Components_b_9.html</link>
<pubDate>2012-04-11</pubDate>
<description><![CDATA[ Question: &ensp; I would like to ask what is the reason or purpose of listing fire alarm systems and components. I don't need the procedure or the definition, that is spelled out in NFPA 72. But what is the reason to start with? My first assumption is that it is used because most fire alarm companies do not have the expertise or capabilities to determine if components (relays, etc.) are compatible with the control equipment and also that they meet the basic requirements spelled out in NFPA 72.  ]]></description>
<guid isPermaLink="false">http://www.totalcomputing.net/Purpose-of-Listing-Fire-Alarm-Components_b_9.html</guid>
<content:encoded><![CDATA[Question: &ensp; I would like to ask what is the reason or purpose of listing fire alarm systems and components. I don't need the procedure or the definition, that is spelled out in NFPA 72. But what is the reason to start with? My first assumption is that it is used because most fire alarm companies do not have the expertise or capabilities to determine if components (relays, etc.) are compatible with the control equipment and also that they meet the basic requirements spelled out in NFPA 72. ]]></content:encoded>
<isc:description><![CDATA[From the Fire Alarm Engineering discussion group on LinkedInQuestion: &ensp; I would like to ask what is the reason or purpose of listing fire alarm systems and components. I don't need the procedure or the definition, that is spelled out in NFPA 72. But what is the reason to start with? My first assumption is that it is used because most fire alarm companies do not have the expertise or capabilities to determine if components (relays, etc.) are compatible with the control equipment and also that they meet the basic requirements spelled out in NFPA 72. Answer:&ensp;When a manufacturer approaches U.L. for a &quot;Listing&quot; to UL 864, they must also submit all devices that U.L. will test with that panel to ensure compatibility and proper function within the limits of the listings for the components that may be attached. The &quot;Compatibility List&quot; included in the Owner\Installation Manual for each system includes the part number\models of every device that was tested with the FACP by U.L., hence, they are &quot;listed for the intended use&quot;, i.e., attachment to that make and model FACP.Manufacturers are in the business of selling product, so they quite naturally tend to only pay U.L. for testing devices they manufacture for &quot;listing&quot; with their panels. Some peripheral manufacturers do just the opposite: They submit their devices for testing and compatibility listing with those FACPs they feel they can match up well with.From an operational and liability standpoint, failure to use devices &quot;listed&quot; for use with any FACP opens up the seller or installer to great risk, should a device or system failure result in the loss of life or property. Criminal and\or civil liability may also be incurred by not following the manufacturers' rules and listings when installing a system. Basically, you either follow the listing, or you pays your money and takes your chances.Mike Agri - Engineered SystemsTC Life Safety]]></isc:description>
<isc:productid><![CDATA[9]]></isc:productid>
<isc:author><![CDATA[Administrator]]></isc:author>
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<title><![CDATA[Grounding and Bonding of Gas Piping in Buildings]]></title>
<link>http://www.totalcomputing.net/Grounding-and-Bonding-of-Gas-Piping-in-Buildings_b_8.html</link>
<pubDate>2012-03-19</pubDate>
<description><![CDATA[ The following is a comment from a Linked-In discussion concerning grounding and bonding of gas piping in buildings. It is a critical piece to understand when attempting to differentiate between GROUNDING and BONDING. The difficulty arises because bonding, in most cases, achieves at least some degree of grounding as well, but the intent, methods, and applicable conductors can be significantly different. ]]></description>
<guid isPermaLink="false">http://www.totalcomputing.net/Grounding-and-Bonding-of-Gas-Piping-in-Buildings_b_8.html</guid>
<content:encoded><![CDATA[The following is a comment from a Linked-In discussion concerning grounding and bonding of gas piping in buildings. It is a critical piece to understand when attempting to differentiate between GROUNDING and BONDING. The difficulty arises because bonding, in most cases, achieves at least some degree of grounding as well, but the intent, methods, and applicable conductors can be significantly different.]]></content:encoded>
<isc:description><![CDATA[The following is a comment from a Linked-In discussion concerning grounding and bonding of gas piping in buildings. It is a critical piece to understand when attempting to differentiate between GROUNDING and BONDING. The difficulty arises because bonding, in most cases, achieves at least some degree of grounding as well, but the intent, methods, and applicable conductors can be significantly different.This comment, posted by Aron Kumar, explains the difference about as well as it can be:Bonding is the physical connection of the conductive materials of equipment and metal objects to the ground reference point in order to prevent the generation of voltage potentials between conductive materials. This has nothing to do with making a gas piping system part of the grounding grid (which it is not to be part of, as in using gas piping for grounding purposes) but has everything to do with attempting to establish a safe, zero voltage potential between conductive materials. Bonding also provides lightning protection by preventing (hopefully) the sudden increase of voltage on one conductive material (metal gas supply, CSST, cable TV, telephone cable, etc.) as opposed to another conductive material. The differential voltage between these materials, circuits, results in damage to sensitive devices, and in the case of CSST can result in blowout with arcing and a fire.The grounding requirements for lightning protection are not the same as for electrical bonding or as for the NEC electrical grounding requirements. Typical electrical grounding and bonding in the NEC is for residential/commercial voltages at a frequency of 60 HZ, which travel within the conductive material. The grounding and bonding requirements for lightning protection are for significantly higher voltages at high frequencies that travel along the exterior surface of the material.A safe grounding and bonding system must consider the voltage potential, conductive ground return, ground voltage differences, single point grounding, lightning protection, electrical safety, and lightning protection. The grounding and bonding conductor sizes and materials are not the same for typical NEC requirements for residential/commercial systems and for lightning protection. An example is the fact that rebar in concrete is now allowed by the NEC to be used as a primary grounding point for the electrical system. However, lightning protection requires the primary grounding point be located outside the building and via driven grounding rods, and that all grounding rods be connected (bonded) to each other, and that all conductive materials/circuits that can be exposed to lightning (such as a metal gas pipe) be bonded to the grounding point.]]></isc:description>
<isc:productid><![CDATA[8]]></isc:productid>
<isc:author><![CDATA[Mike Agri]]></isc:author>
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<title><![CDATA[Lightning & Surge Protection 101 - Part 5]]></title>
<link>http://www.totalcomputing.net/Lightning-Surge-Protection-101--Part-5_b_7.html</link>
<pubDate>2012-01-26</pubDate>
<description><![CDATA[ Today, wireless systems for telephone, alarms, security, and other applications are all the rage. Here is a cautionary tale.At one time, IBM, and later Simplex Time Recorder Company, manufactured electronic, self-correcting clock systems that employed a high power frequency generator wired in parallel across the electrical service. The last minute of every hour, the frequency generator would be turned on for a fixed period of time, and insert one of several available frequencies on the entire AC distribution system in the entire building. The secondary clocks, which plugged into any available single phase, 2-wire 120V outlet, each contained a signal amplifier which turned the frequency into a voltage that would energize a solenoid operated correction mechanism in each clock for system-wide synchronization. It was discovered that If two relatively proximate facilities running on the same utility feed just happened to be set to correct using the same frequencies, it would sometimes result in cross talk between building clock systems which might have one or both facilities with a slightly different Master Clock time setting cause an adjacent facility to also go into correction, with the usual result of each or both systems advancing, every hour.  ]]></description>
<guid isPermaLink="false">http://www.totalcomputing.net/Lightning-Surge-Protection-101--Part-5_b_7.html</guid>
<content:encoded><![CDATA[Today, wireless systems for telephone, alarms, security, and other applications are all the rage. Here is a cautionary tale.At one time, IBM, and later Simplex Time Recorder Company, manufactured electronic, self-correcting clock systems that employed a high power frequency generator wired in parallel across the electrical service. The last minute of every hour, the frequency generator would be turned on for a fixed period of time, and insert one of several available frequencies on the entire AC distribution system in the entire building. The secondary clocks, which plugged into any available single phase, 2-wire 120V outlet, each contained a signal amplifier which turned the frequency into a voltage that would energize a solenoid operated correction mechanism in each clock for system-wide synchronization. It was discovered that If two relatively proximate facilities running on the same utility feed just happened to be set to correct using the same frequencies, it would sometimes result in cross talk between building clock systems which might have one or both facilities with a slightly different Master Clock time setting cause an adjacent facility to also go into correction, with the usual result of each or both systems advancing, every hour. ]]></content:encoded>
<isc:description><![CDATA[Part 1 | Part 2 | Part 3 | Part 4 | Part 5Have you heard the one about...Today, wireless systems for telephone, alarms, security, and other applications are all the rage. Here is a cautionary tale.At one time, IBM, and later Simplex Time Recorder Company, manufactured electronic, self-correcting clock systems that employed a high power frequency generator wired in parallel across the electrical service. The last minute of every hour, the frequency generator would be turned on for a fixed period of time, and insert one of several available frequencies on the entire AC distribution system in the entire building. The secondary clocks, which plugged into any available single phase, 2-wire 120V outlet, each contained a signal amplifier which turned the frequency into a voltage that would energize a solenoid operated correction mechanism in each clock for system-wide synchronization. It was discovered that If two relatively proximate facilities running on the same utility feed just happened to be set to correct using the same frequencies, it would sometimes result in cross talk between building clock systems which might have one or both facilities with a slightly different Master Clock time setting cause an adjacent facility to also go into correction, with the usual result of each or both systems advancing, every hour. Because you can doesn't mean you shouldAn independent care elderly facility installed an inexpensive packaged fire alarm system that included one 24VDC door magnet set to release a stairwell fire door on every alarm. The magnet was controlled through an NO contact of an integrated alarm relay in the FACP, and powered by the panel's [limited] 24 VDC power supply. The first time we tested the fire alarm system on battery standby, the FACP's power supply failed. We replaced the power supply, and it failed as soon as we duplicated the test. The back EMF from the collapsing magnetic door holder's field was apparently severe enough to damage the motherboard voltage regulator. In addition, the door holder load had not been included in the battery calculations of this Auxiliary Fire Alarm System. The manufacturer documentation specified the [limited] available 24VDC output was for powering 4-wire smokes, and other low current devices.The contractor who installed fire alarm auxiliary relay-controlled 120 VAC door magnets in elevator lobbies and corridor smoke doors in a local hospital did a very nice, neat job, however, when the alarm system was activated, one circuit of door holders failed to release, even though the 3PDT control relay clearly operated and opened the power to the magnets. If you manually released a door on the circuit, and then tried to re-engage the door magnets, the doors would no longer hold open. Upon further investigation, it was found that the neutral for the circuit in question was used as the switched leg, and through inductive coupling to the EMT containing the wiring, the magnets were able to remain energized enough to hold the doors.When a ground fault is not a ground faultA fire alarm panel in a large, un-sprinklered Vo Tech school went into ground fault [randomly]. A check of all field wiring, and the systems itself divulged no apparent reason. As luck would have it, I happened to be standing in front of a clear panel one morning, when suddenly a ground fault appeared. Coincidently, I noticed the sound of something starting. I walked towards the sound, and around the corner from the FACP sat a brand new VFD (Variable Frequency Drive). Whenever the drive started, the FACP, which was fed out of the same sub-panel that physically sat between the FACP and the VFD, would go into ground fault. Further investigation revealed that the service ground, about 150' from the FACP was badly corroded, and there was no bonding jumper around a water meter that was installed a few feet downstream of the service ground. The sub-panel was part of an old 3 phase 208V, ungrounded system. There was no ground bus in the sub-panel so the installing electrician had “referenced” ground by connecting to the painted surface of the FACP.A high rise VA hospital got a brand new FACP that immediately began sending random alarms from one particular floor. No operated devices were found, and no wiring faults could be found, so the zone module was replaced. The problem remained, so all smoke detectors were replaced, with no success.I was discussing the problem with the hospital's chief mechanic, who also happened to have been assigned as the VA's eyes on site during the building's construction. In passing, he remembered “they had discovered” the building's 7th floor, [the hospital was built on a hill] just happened to be the intersecting point of several local TV and Radio Station transmitter signals, and this had caused some difficulties with other systems when the building was first opened. A sweep of the 7th floor FA wiring disclosed that a number of J-box covers had not been installed by the contractor. A check of the remainder of the building revealed more missing covers. As soon as the system was properly buttoned up, the false alarm incidents promptly ceased.]]></isc:description>
<isc:productid><![CDATA[7]]></isc:productid>
<isc:author><![CDATA[Mike Agri]]></isc:author>
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<title><![CDATA[Lightning & Surge Protection 101 - Part 4]]></title>
<link>http://www.totalcomputing.net/Lightning-Surge-Protection-101--Part-4_b_6.html</link>
<pubDate>2012-01-13</pubDate>
<description><![CDATA[ When people ask me what I do, my usual response is, &quot;I'm the last guy that gets called to fix something after everybody else who could possibly screw it up has been brought in and has failed to find or fix the problem, and usually, only after sins of the installer or subsequent service\installation people have been obscured or exacerbated by subsequent repair or troubleshooting attempts.&quot; Over the course of a career, a manufacturer's technical representative gets to see about every kind of &quot;equipment failure&quot; imaginable, and even some that aren't so imaginable. ]]></description>
<guid isPermaLink="false">http://www.totalcomputing.net/Lightning-Surge-Protection-101--Part-4_b_6.html</guid>
<content:encoded><![CDATA[When people ask me what I do, my usual response is, &quot;I'm the last guy that gets called to fix something after everybody else who could possibly screw it up has been brought in and has failed to find or fix the problem, and usually, only after sins of the installer or subsequent service\installation people have been obscured or exacerbated by subsequent repair or troubleshooting attempts.&quot; Over the course of a career, a manufacturer's technical representative gets to see about every kind of &quot;equipment failure&quot; imaginable, and even some that aren't so imaginable.]]></content:encoded>
<isc:description><![CDATA[Part 1 | Part 2 | Part 3 | Part 4 | Part 5Being the Detective that Solves the &quot;Case&quot;When people ask me what I do, my usual response is, &quot;I'm the last guy that gets called to fix something after everybody else who could possibly screw it up has been brought in and has failed to find or fix the problem, and usually, only after sins of the installer or subsequent service\installation people have been obscured or exacerbated by subsequent repair or troubleshooting attempts.&quot; Over the course of a career, a manufacturer's technical representative gets to see about every kind of &quot;equipment failure&quot; imaginable, and even some that aren't so imaginable. As Hugh Laurie of the TV series &quot;HOUSE&quot; is fond of saying, &quot;everybody lies&quot;, and my personal experience is, that can include the very people who hire me to help them &quot;solve&quot; problems. I have been in more than one situation where an individual manager or employees knew what, why, and where of the problem, but did everything they could to keep me from finding it. The bottom line is, nothing is impossible, and in many cases, you really don't know who can and cannot be trusted to provide full and accurate guidance, no matter how improbable that might seem at the moment. If your eyes, head, test equipment, and instincts are pointing you in a different direction from everyone else, remember that no avenue of investigation should be ignored. In my career, I have encountered just about everything that is bounded by stupidity to sabotage. Some things that I have learned over the years that you may find of some use are:Never presume anything is good if it's brand new out of the box. In fact, I find it has been useful to adopt the opposing attitude that every &quot;new&quot; part or piece of equipment is defective, until proven otherwise. Don't believe manufacturers' tech support people who are telling you that their equipment &quot;can't do&quot; what you are observing it doing. Nobody tests commercial systems under every possible combination of conditions. Because a piece of equipment wasn't designed or intended to act in a particular fashion doesn't mean that, under the right set of circumstances, it can't or won't. If the same part fails more than once, there is a reason, and you probably didn't find it the first time around. It may be time to break out the old meter[s] and expand your search. It never hurts to take a closer look, even if all you do is satisfy yourself that there is nothing going on that needs to addressed, even though correcting the root cause may be beyond your capabilities or the limits of your tradesperson's license. [In the last part of this series, we will look at a &quot;problem&quot; whose solution involved 4 different trades.] Go with your gut. If a little voice in your head is telling you that you missed something important, you probably did. Over the years, I have observed an increase of phenomena I call unintended interactions of building sub-systems. Two common culprits that can be the bane of a low voltage contractor's existence are VFDs and electronic ballasts. Since some broadcast bands have been returned to the FCC, and then re-sold to telecommunications and other manufacturers, I fully expect there will be a tipping point where unintended interactions will begin to cause instability in some currently popular wireless systems.As a technician, I literally hate to not know what I have &quot;fixed&quot; because I invariably leave with the dreaded expectation that the problem will re-appear, when least convenient [Murphy's Law]. Admittedly, a certain degree of obstinacy is sometimes needed to find all the answers, and for some, finding out &quot;who done it&quot; is its own reward.Next time: Some of the more distinctive and\or interesting situations I have encountered.]]></isc:description>
<isc:productid><![CDATA[6]]></isc:productid>
<isc:author><![CDATA[Mike Agri]]></isc:author>
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