Thursday, January 11, 2018
Tips for Fire Alarm System Installation
by ©Ted Smith on 10/04/12
I have been involved with coordinating the completion and testing of complex fire alarm systems and smoke evacuation systems. Often the project is in a schedule crunch to complete and to receive at least a temporary certificate of occupancy. Of course, an integral part of the TCO is a functioning fire alarm system. The last time I was involved in this type of situation I made some notes of things that could have been done from the beginning of the fire alarm installation that would have made the finishing process much easier. Perhaps these things may help you on your next fire alarm installation.
I. The Rough Installation of Conduits
Modern fire alarm systems are very complex electronic, programmable systems. They operate by reading levels of resistance, current and voltage within the system. These readings are affected by capacitance and inductance on the circuit. Excessive taps, loops, and wire on the system will introduce capacitance and inductance on the circuit and will cause the fire command center computer to have difficulty reading the devices. This will create a great deal of troubleshooting and rework for the fire alarm installation crew. These problems can be avoided by addressing them in the rough conduit installation phase. Follow these guidelines and you cannot go wrong. Remember that Murphy's Law will prevent the person that installs the conduits from pulling the wire and terminating the devices. No matter how sure you are that the same person will install conduits, wire and terminate devices, mark every conduit with a "Sharpie" at every junction box. I recommend using reverse marking. Here is a recommended system for marking that does not take a great deal of time to accomplish and saves an enormous amount time at the end.
a. Mark every junction and device box on a set of as-built prints. This is a crucial step.
b. Number each junction and device box. You can use whatever numbering system you wish, but I recommend keeping it simple.
c. As you install the conduits, mark the conduit at each junction box with the number of the junction box that conduit came from. For example: A 3/4" conduit connects junction boxes 2 and 3. At junction box 2 mark the conduit with a 3. At junction box 3, mark the conduit with a 2. Following this process will speed up wire pulling processes and reduce mistakes. It will also help you trouble shoot problems as they are discovered without spending a great deal of time trying to remember how the conduits were installed. Plan the installation carefully. Spending time with a set of blueprints and planning the rough installation will pay incredible benefits at the end of the project. Here are things that need to be planned and written down on a set of blueprints prior to the installation.
a. Fire alarm systems are complex enough without complicating the process by requiring complex make ups at junction and device boxes. Determine the devices in each loop and identify their locations on the print before doing any planning.
b. Now determine a route for your cable through each device in the loop. Your goal is to have only two cables in each box for each loop, one in and one out. Modern systems can be "tapped" however every tap increases your chances of problems on the circuit at the end and increases the expense of the troubleshooting. I have always used the guideline of no more than 4 cables in a junction box or device.
c. Draw the route for the loops on a blueprint. Draw in junction boxes and device boxes and number them. Write the type of cable and number of cables that need to be pulled into each conduit at every junction box. I like to make the following notes at each junction box on my prints. The junction box number, the number of conduits and where they go and the number of cables and type in each conduit. For example: J-box 1.3/4" EMT to J-box 2. Two 14/2 shielded Black/Redcables.3/4" EMT to J-box 3. Two 14/2 shielded Black/Red cables.
Of course, the best laid plans need to be changed sometimes. It is critical that the installation crew understands that if they have to make some changes, they need to mark these changes on the installation print.
d. Be sure to check the elevator drawings and elevator recall design. The needs of the integration with the FA system is often overlooked. It is important to find that early and write RFIs and resolve issues.
Follow the plan. Do not make your efforts a waste of time. You need to transmit this plan to the field, explain it to them and make sure they understand that the system needs to be roughed in according to this plan, even if they are convinced that they have a better way. Of course you can take suggestions from the field, but the plan needs to be modified on paper if you decide to make changes. Do not let the installation crew change it as they wish.
a. Follow up periodically and ensure the installation is being installed according to your plan. This means physically checking it, not just asking them if they are following it. If they are not following it, you need to make sure they understand that you will expect them to have a good reason for not following the plan and that their changes should appear on the installation print.
b. Have the crew mark of installed conduits daily with a highlighter, so you have a constant tracking of completion and a double check that you didn't miss anything. I know that this seems like a large amount of time planning. It is, no doubt, a difficult and time-consuming process.
Remember two things as you are doing it:
1. You have time now, at the beginning of project. Can you recall a project where you had enough time to find, analyze and rework problems in the system at the end? How many times have you had to use overtime to get the system working on schedule?
2. The more planning you do now the less troubleshooting and correcting you will do later. So when would you rather spend the time: At the beginning or the end? Spend some time training your rough installation crews on proper conduit installation techniques. Make sure they understand the importance of paying attention to details. Fire alarm cable is very easily damaged so care must be taken to install conduits correctly.
a. Cut all conduits straight
b. Ream every conduit thoroughly
c. Ensure all connectors and couplings are securely fastened and that conduits are firmly seated in the connections.
d. Physically verify these things are being done periodically during the installation.
II. Wire Pulling
The wire pulling for the fire alarm system is one the most critical aspects of the installation. Fire alarm cable is not as tough as THHN wire and is very susceptible to damage. This damage can lead to shorts and ground faults that will haunt you at the end. Here are some tips to reduce these problems.
Spend some time physically training your crews in the art of pulling wire. Do not assume they know how. Teach them the fundamentals of feeding wire directly into a conduit and how to use pulling soap.
Use pulling soap on even small pulls when working with Fire Alarm cables. This will help reduce the damage to the wires.
Use carpet scraps to cover ceiling grids, beams and pipes that cable will have to be pulled over.
Make a cardboard funnel to insert into all conduits and pull the cable through the funnel. This will prevent cuts and scrapes to the cable.
Be sure to verify every cable before pulling. Check it against the installation print for correctness.
Label every cable after pulling. Use white tape and pen to mark the cables. No cable, no matter how obvious it may seem, should be left unmarked.
III. Terminations and Make Up
Here are some tips to follow when terminating devices that should help reduce problems. Make a set of "cheat sheets" for the fire alarm crew. Include each device type they will encounter. Make a wiring diagram for the device and include wire colors. Ensure that no one makes a termination that does not match the wiring diagram. If the cables in the box do not match the diagram, they need to ensure they research the problem and find a solution. Do not just assume the wrong cable was pulled and break out the phase tape. Spend some time and train them on how to make the terminations for each device type. Use physical examples.
Ensure they know how much wire to strip to make the termination and do not over-strip. Ensure they understand to not make taps on the device. If taps are used, a splice should be made, and a pigtail terminated to the device. Making taps on the device will increase capacitance and resistance on the circuit. You will end up changing them to splices with pigtails at the end any way. Of course, you will have to find them first.
Ensure the crew understands the common causes of ground faults and how to avoid them.
IV Coordination
Modern fire alarm systems are integrated into the HVAC systems in the building not to mention the Ansul systems and fire pump systems and the emergency power backup systems. On a large project, several different trades and contractors will have to work together to make the system work as a whole. On a really good day, this is a difficult process. When the project is coming to an end, everyone is under pressure and emotions are intense and it is darn near impossible.
All too often we take the following approach: "We have our input/output module in place. Our part is done. The rest is up to them."
Let me give you an example. A fan coil unit needs to be shut down in the event of a fire alarm. The mechanical contractor supplies and installs the fan coil unit. The mechanical contractor supplies the disconnect and motor starter and the electrical contractor wires the power feed to the disconnect. The building systems control contractor supplies the low voltage temperature controls for the fan coil unit and wires the control wiring. The fire alarm contractor supplies the fire alarm control module that will monitor the FCU and can open a switch for the fan coil unit and will monitor if that has shut down. Everyone does their part. The fan is installed, the electrical power is available, the control wiring is in place to start and stop the fan based on the thermostat and the fire alarm control module is installed.
If I were to ask each contractor if they were done, I would be told yes. The problem is that the fire command center will not stop that motor when an alarm occurs. A signal will be sent to the control module and the contacts will close on the control module, but no one has made a connection between the control module and the thermostatic controls for the FCU. The fire alarm contractor and the controls contractor will probably both argue that it is the others responsibility, and the arguments, e-mails and notifications will begin. The contract will be consulted, and the specifications reviewed by both sides and most likely the discovery will be made that it is a gray area however their interpretation is that it is clearly the other person's responsibility.
Sound familiar? This scenario incompletely avoidable. Here is how.
Early on, at the beginning, identify every piece of equipment the fire alarm system must interact with for the smoke control system to work.
2. Write them all on a list.
3. Make columns next to the list, one for each of the following questions.
a. Voltage
b. Phase
c. Where is it located?
d. What does the FA system do to it? Start it, shut it down, etc.
e. What is its purpose? Heat, exhaust, pressurization, etc.
f. Who controls it normally?
g. Does it run constantly?
h. Is it controlled thermostatically?
i. What is the control voltage?
l. Are there dampers?
m. Are there safety interlocks for the dampers? (Most pressurization systems are equipped with a normally open interlock system that prevents the fan motor from operating if the dampers are closed so we do not blow up the duct work. The fire alarm system opens the dampers and starts the motor, so often times they are also responsible for the safety interlock. It only makes sense. If a pressurization fan only starts by the fire alarm system and the dampers only open based on the fire alarm system, why would the mechanical or electrical contractor be responsible for the interlocks? By the way, if the interlock is not designed, write an RFI, it will be necessary most likely.)
o. Who do I need to contact for the answers?
p. Who will make the final termination?
Research each of the questions and fill them in as you receive them. Review this sheet every week and make calls or write letters to the appropriate people until you have every answer.
Remember, the squeaky wheel gets the grease. You need to ask the questions to the general contractor so that you have a record, but you should also coordinate directly with the appropriate contractor.
Do not ask questions like "Who makes the final termination for the Ansul system monitoring?" or "We need to know how to make our terminations in the control system for the fan coil units" You will be waiting a long time for these answers.
Here is an example of an RFI using the example I used earlier.
"We need to shut down fan coil unit 23 in the event of a fire alarm. We have done some research and have determined that you will be controlling this three-phase, 480V fan coil unit by using a magnetic starter with a 24-volt relay. We believe you will be using a normally closed contact to stop the unit. We have a 24V control module that has a normally closed set of contacts that we can control. We would like to wire our normally closed set of contacts in series with your normally closed set of stop contacts so that we can interrupt the control circuit and shut down the fan in the event of an alarm. Our contacts will have to be wired in front of your stop contacts for proper fire alarm monitoring to occur. We recommend that you install and wire your contacts for the fan coil unit and then contact us when you are complete. We will then have our personnel interrupt the lead contact on your normally closed contacts and wire our normally closed contacts into series with yours. We further recommend that we arrange to have a representative from both of our organizations present for a pretest walk of the fans before we do any fire department testing. Please confirm that this interconnection will fulfill both our requirements for control of this unit. "By doing your research, finding a way to control the units and then making the recommendations, you will get results. You are the expert, act like one. The alternative is to end up making the terminations anyway so that the system will work and spend an enormous amount of time and effort arguing about it at the end. By the way, don't try to blame it on the engineer. The above example is not an engineering responsibility, it is an installation responsibility.
TRIM AND AVODING GROUND FAULTS
When doing your trim, always trim out by initiating device circuit or NAC. Start at the last device and work your way back to the beginning. Check the wires for ground faults at the last device and if any found, find them and fix them and then trim the device. Then go to the next one in and repeat the process. If you do this, you will have a system free of ground faults when you turn it on. What a wonderful thing to behold. Some final things to watch for:
Detectors in elevator machine rooms must be located within 3feet of the sprinkler head
The fire alarm company always provides the speakers and phone jacks for the elevator cars to the elevator company. They will typically install them for you, but you have to supply them.
The "Fireman's Hat" symbol in the elevator cab must be wired and programmed to flash if the detector in the elevator control room is activated. This is a signal to the firemen to not use this elevator as there is most likely a fire in the control room.
Be sure to work closely with the fire alarm programmer during the troubleshooting process. Treat this person well. They can provide you with an amazing amount of useful information when troubleshooting.
Mapping of the fire alarm system by the programmer is a time-consuming process that ties up the entire fire alarm system program. There is a direct correlation between the programmer's frustration level and the number of times they have to map an area of building. To reduce problems and the number of mappings, ensure that you have a green light on every device in a loop before asking them to map the loop. If you do not have a green light on each device, troubleshoot the circuit until you do, then ask them to map the loop Use the installation prints and a highlighter for this process. After the devices are installed, wall the floor systematically and mark off each device on the print, install any missed devices and troubleshoot devices that are not responding with a green light. Then and only then, map the system and work out the troubles.
Always schedule troubleshooting time into your plans. No fire alarm system works perfectly the first time. They all have some problems, and these problems have to be found and eliminated. The more complex the system the more troubles you will have to iron out. Make sure you leave yourself some time.
A good guideline is one man, 4 hours per every 200 devices. Remember that troubleshooting is not something that can be accomplished with multiple people effectively, so adding people will not reduce the time. Also remember that this is assuming that the tips above were followed, and the system was planned, installed and terminated carefully. If the system was installed on the fly, routing of conduits was determined by multiple installers, wire pulling was done by multiple people with no overall plan to follow or training, terminations were made by multiple people with no overall written plan and training and no physical follow up was done to ensure a plan was followed carefully and finally if no exact and detailed set of as-builts are available, then the amount of time you will need to troubleshoot is anyone's guess. My guess would be no less than two men, 12 hours for every 200 devices, assuming they are knowledgeable troubleshooters.
I hope these tips help with your next fire alarm installation.
Ted "Smitty" Smith
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