Sunday, March 29, 2015

Fire Alarm Underground Conduits

Is it OK to Install Fire Alarm Cable underground?


PIV Post Indicator Valve for Fire Alarm Sprinkler System
Post Indicator Valve  with Fire Department Connection
A common task when installing a new fire alarm system is undergrounds. Typically when a C-16 or fire protection (fire sprinkler) contractor installs their incoming lines they will at the same time install the necessary fire alarm underground conduits for the connections to the backflow prevention switches (OS&Y Outside Screw and Yoke) or PIV (Post Indicator Valve) switches. However, sometimes this task could be a part of the fire alarm contractor's scope of work. If you find yourself installing underground conduit or direct burial cable make sure to follow all of the national codes and regulations.

Direct Burial Cable as an Alternate to Conduit


Backflow Preventor OS&Y For Fire Alarm Sprinklers
Backfloe Preventor with OS$Y Switches for Fire Alarm
Some contractor's may choose to use direct burial cable also referred to as UF Cable commonly identified by its grey coating. Direct burial fire alarm cable not protected in conduit must be installed at a depth of 24" below grade with either schedule 80 PVC or Rigid conduit stubs up to your box. When fire alarm cable is installed within plastic conduit it must be 18" deep and installed with schedule 80 PVC. This is a more durable plastic conduit (grey color) than the common household irrigation lines. The best way to install these conduits or cable is with a Ditch Witch. Simply set the depth and go.

Junction boxes that are run out into the middle of a remote area without an anchor point must have the schedule 80 PVC embedded in the concrete to support the box. Another method is to attach the box to a post that is either driven or buried in the ground 18" and connects directly to the schedule 80 PVC conduit. Junction boxes should be installed at least 12" above grade but not more than 18" for the unattached method.

See also conduit bending videos.

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Wednesday, March 25, 2015

Wheelock LED Notification Appliances

Are the new Wheelock LED Series Notification Appliances all They're Cracked up to be?

Although the Wheelock LED (Light Emitting Diode) notification appliances are not so new anymore, they still seem to bring up quite the conversations.  Like any new fire alarm equipment, it is wise to let them prove themselves before you actively start specifying and installing them throughout all of your sites.  Well that time has come and gone as these LED strobes and horn/strobes have been flying off the shelves.

Our goal here is to make you aware of their capabilities so that you can decide when and when not to include them in your fire alarm system design criteria.  For this comparison I am going to be using the new Wheelock LED Series Horn/Strobe (model LHS) and the Older Wheelock Exceder Series Horn/Strobe (model HS).  Note that both models comparisons will be based off wall mounting, 24 VDC, 3 Tone Temporal Output, and set at the High Setting.  This should keep everything fair for the sake of the article.

Lets take a look at differences and similarities of the two notification appliances.




As you will notice from the chart I created above, the two notification appliances have quite a few differences.  One of the more noticeable differences is the candela selection available.  You can see that the Exceder series covers standard candela all the way up to high candela at 185 CD.  On the other hand the Wheelock LED series appliance only covers the standard candela range.  

Wheelock LED Series Horn Strobe LHNow the biggest item that everyone is discussing around the new LED series strobes is the lower current draw.  We all know the lower the current draw, the more appliances we can fit on a circuit. More appliances on circuits results in few circuits, and less remote power supplies.  As you may notice in the "Current Draw" tables above, the LED series appliances have a lower current draw through the range of 15 CD - 75 CD.  Once you jump up to 110 candela, the standard Exceder series with Xenon bulb actually draws less.

Wheelock Exceder Series Horn StrobeIt all depends on you application as your facility may demand more 110 candela strobes in comparison to your lower levels (15-75).  In this case you would probably want to stay with the older Exceder Xenon bulb technology.  Now if you have an office building with multiple corridors, you can get away with 15 candela and the LED strobes would be your best bet.

*It is also very important that I make you aware that Cooper-Wheelock has made it clear that both the Xenon bulb and LED style visual appliances are compatible on the same circuits and will successfully SYNC if you use the proper remote power supply or sync module such as the DSM-12/24.

I hope this information assists you in your design as both models are great products with their own special characteristics.

Tuesday, March 24, 2015

Fire Alarm Testing Corrections Made Easy

How do you mark the devices that need a return service trip to correct?

When you are performing a fire alarm system test or fire alarm system pre test, make sure to check every fire alarm device and notification appliance.  This includes audible visual, smoke detectors, heat detectors, pull stations, Ansul (hood systems), door holders, and the one everyone skips, duct smoke detectors.

When checking these devices it may become a burden to write down the exact location of a fire alarm device or appliance that did not function correctly.  This really applies to non addressable devices as these devices have a location/description programmed into the fire alarm control panel. Devices such as conventional initiating devices, strobes, horns and speakers are harder to keep track of.  

Here is a little trick that will help shave time off your fire alarm test.  Use small bright yellow colored stickers to mark the fire alarm devices or appliances that did not function correctly.  This will make it easy to come back and check or note deficiencies.

Wheelock RSS-24MCW Wall Mounted Strobe

With door holders, you can mark the actual magnetic holder if it did not release, or you can mark the hardware mounted on the door if the door did not close and latch.  It makes it easy to come back and accurately make notes on your fire alarm test form otherwise know as the NFPA 72 testing and inspection sheets or the Record of Completion if a new system.

You can also get creative and use different colors for different scenarios.  For example, lets say you have a duct smoke detector that went into alarm but did not shut down the air.  Use a green sticker for HVAC shutdown.

Try it out and let us know what you think.

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Elevator Shunt Trip with Sprinkler Heads

What is Elevator Shunt Trip?


Elevator shunt trip wiring deta
Elevator Shunt Trip Wiring Detail
Elevator controls play a huge role in fire alarm system emergency functions. Whereas elevator recall captures and sends the elevator cab to safe floors, shunt trip works a little different.  Elevator Shunt Trip is a function that involves shunting the breaker that controls the elevator equipment prior to the release of the automatic sprinkler systems.  This procedure is completed via the activation of heat detectors (addressable or conventional).  Now keep in mind that not just any heat detector within the facility will be required to activate the elevator shunt trip procedure.  The only heat detectors that will tell the fire alarm control panel to shunt the elevator breaker are the ones located in the elevator shaft or hoistway and elevator equipment room.  Per NFPA 72 2013 edition section 21.4.2* the heat detectors that are in place to shunt the elevator power shall be installed within 24" of each sprinkler head within the area.  On top of this section 21.4.1* states the heat detector used for shunt trip shall be set at a lower temperature and higher sensitivity than its adjacent sprinkler head.

One last thing, the activation of heat detectors can delay the shunt trip via programming for a delay time not to exceed the time it takes the elevator cab starting at the top level to reach the lowest level of exit discharge.  The purpose behind this allowance is to increase the potential for elevators to complete their travel to the recall level.  Make note that the requirements of A17.1/B44 Safety Code for Elevators and Escalators would still apply.

Now if you choose to use the method of waterflow or pressure switch to activate you elevator shunt trip, any time delay switches or capability will not be permitted per NFPA 72 2013 section 21.4.3.
video


When the shunt trip breaker is activated, the breaker switch itself will be between on and off.  To reset the breaker, make sure the controlling fire alarm system is reset and back to normal.  Once the FACP is reset, flip the shunt trip breaker all the way towards the off position (should be some tension) and then flick it all the way back to on.  Review the short video for more details on resetting a shunt trip breaker.

Code References for Elevator Shunt Trip:


ASME A17.1-2004

2.8.2.3.2 In jurisdiction not enforcing the NBCC, means shall be provided to automatically disconnect the main line power supply to the affected elevator upon or prior to the application odf water from sprinklers located in the machine room or in the hoistway more than 600 mm (24") above the pit floor.  This means shall be independent of the elevator control and shall not be self-resetting.  The activation of sprinklers outside of the hoistway or machine room shall not disconnect the main line power supply.

ASME A17.1-2013

2.8.3.3.2 In jurisdictions not enforcing the NBCC, where elevator equipment is located or its enclosure is configured such that the application of water from sprinklers could cause unsafe elevator operation, means shall be provided to automatically disconnect the main line power supply to the affected elevator and any other power supplies used to move the elevator upon or prior to the application of water. (a) This means shall be independent of the  elevator control and shall not be self-resetting.

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Monday, March 23, 2015

Magnetic Door Holder for Fire Door

Depending on your fire alarm installation, you may need to install a magnetic door holder at the location of each fire door.  A magnetic door holder is a relatively simple device that when powered, typically by 24VDC or 120VAC, will create a magnetic pull.  The magnetic portion of this device is installed on the wall that meets the open fire door.  Now to tie this whole concept together, you will need to install the necessary hardware on the fire door itself.  It is very important that you line the door hardware up with the magnetic door holder as close as possible.  If the two do not meet precisely, you may not acquire the necessary contact to hold open a heavy fire door with the extra tension caused by the closure mechanism. 

Now with all of that said, you need to make sure that the magnetic door holder is mounted securely within the wall.  Be sure to not use cut in boxes, screw in type anchors or even toggle bolts.  This device needs to be mounted to the structure.  The best way to go about this is quite simple. 

Step #1
Mounting Magnetic Door Holder for Fire AlarmOpen the fire door all the way against the wall where the magnetic door holder is to be mounted.  With this done, mark the wall lightly where you will need to roughly install the door holder.  Door holders are typically installed towards the upper/outer edge of the fire door.

Step #2
Use a stud finder to locate a stud near your mark.  Make sure to use the stud that will give you sufficient room to mount your box and still stay within the necessary area of the fire door.  Cut out a section of drywall that runs between two studs.  Make sure the hole is also tall enough to mount a 4S electrical box with brackets.

Step #3
Take some steel stud and cut a piece that matches the width between the two studs.  Now mount your 4S electrical box to a stud of the existing frame via the brackets.  This will secure one side of the box.  Use the piece of steel stud you cut and place it behind your box and between the two studs.  This will give your box the support it requires.  Make sure to fasten the box to your steel stud and then fasten the steel stud at both ends to the existing building studs.

Step #4
Install a single gang mud ring (depth depends on your drywall application).  Once installed, replace the drywall around magnetic door holder back box.  Once the drywall is finished install your magnetic door holder and power it up.

Step #5
With power on the fire alarm door holder, stick the door hardware to the magnetic portion of the device and open the fire door until they meet.  Here we are using the power of the door holder to hold the door hardware while we mark the fire door with the mounting holes.  Most door holders come with a simple to use sticker for purposes of marking the fire door. 

Step #6
Now for the magnetic door holder pictured here, we drilled two 1/8" pilot holes then followed them up with 5/8" holes.  Once we completed the drilling, we screwed the door holder hardware tightly to provided bracket on the back side of the fire door.

Below is a picture of what happens to a magnetic door holder after repeated use if it is not mounted to the structure properly.

Fire Alarm Door Holder Pushed into Wall

Thursday, March 19, 2015

Fire Caulk the Wrong Way

Fire Caulk FailIt is always fun to compare your work to others.  Especially when you have a habit of doing things to current codes and applicable standards.  Today we came across a problem seen all to often on constructions sites both old and new.

Fire Caulk.

It always seems that contractors become very lazy at this stage of the installation.  9 out of 10 times it appears that the installer just slaps some fire caulk around a penetration and calls it a day.  Not realizing how important the fire caulk stage is, most people just leave it.

To install fire caulk the correct way, follow these simple steps:

1. Cut a piece of EMT conduit long enough to penetrate the entire wall (both sides) and have the pipe stick out approximately 6 inches on each side.
2. Pull your wires trough the EMT and then place the EMT through a hole in the fire rated wall.
3. Use mineral wool to pack the ends of the EMT.  Make sure to wrap the mineral wool around the wires and center the wires within the EMT as much as possible.  Now shove the mineral wool inside the conduit.
4. Fire caulk the ends  of the EMT (over the mineral wool) 1" deep and have the fire caulk stick out of the conduit approximately 1/2" to 3/4".
5. Now use the fire caulk around the EMT and the actual fire rated wall.  Make sure to get the fire caulk in 1" and at least 3/4" all around.
6. Make sure to do this on both sides.

How to Fire Caulk Rated Penetrations

CO Detection is the LAW

You may have seen your local hardware store trying to push you on Carbon Monoxide detectors stating its the law.  Read below to know for yourself!

The new requirements in the 2012 edition of the International Fire Code (IFC) and the International Building Code (IBC) require the installation of CO detection in new and existing Group-R and Group-I occupancies, such as hotels, dormitories, apartment buildings, hospitals and nursing homes.

Combination CO Smoke Alarm
Section 908.7 of the 2012 IFC and IBC requires CO detection to be installed in “newly” constructed Group-R and Group-I occupancies if the building contains a fuel-burning appliance or an attached garage. Also CO alarms shall be installed and maintained in accordance with NFPA 720, Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment, and the manufacturer’s instructions.


Section 1103.9 of the IFC covers the requirements for existing Group-R and Group-I occupancies, these requirements are the same as those in 908.7 for newly constructed occupancies.




If sleeping units or dwelling units do not contain a fuel-burning appliance or have an attached garage, however are located within a building with a fuel burning appliance or an attached garage, CO detection is not required if any of the following conditions are present:

• The sleeping unit or dwelling unit is located more than one story above or below any story that contains a fuel-burning appliance or an attached garage
• The sleeping unit or dwelling unit is not connected by duct work or ventilation shafts to an attached garage or any room containing a fuel-burning appliance
• The building is provided with a common area CO alarm system.  Also, Section 908.7.1 of the 2012 IBC and IFC clearly permits system connected CO detectors to be installed as a primary form of protection if they are installed and maintained in accordance with NFPA 720 and listed as complying
with ANSI/UL 2075.

Is a Heat Detector Required for the Elevator Pit

Designers are always asking, "Do I need to put a heat detector in the elevator pit?"

"Are you required to install a heat detector in the bottom of the elevator shaft otherwise known as the elevator pit?".  This is a question that comes up a lot in the fire alarm industry and often has system designers and AHJs (Authority Having Jurisdiction) scratching their heads.  Another related questions is, "Why is there a sprinkler head located at the bottom of the elevator shaft?".  A sprinkler head located in the bottom of the elevator pit is in place to control the spread of fire caused by the ignition of trash and debris that has fallen through the door opening and collected over time.

Heat Detector in Elevator PitThere are two items that need to be present before the requirement of a fire alarm system heat detector is required.  One is the presence of an automatic sprinkler head.  NFPA 13 2010 ed. 8.15.5 states that sprinklers heads are to be installed in the top and bottom of the elevator shaft.  There are exceptions to this rule so keep in mind that not all elevator shafts will incorporate a sprinkler head.  Two is the height in which the sprinkler head is installed off the floor of the elevator pit.  ASME A17.1 states that if a sprinkler head is installed within 24" (2 feet) of the elevator pit floor, it shall be exempt from the special arrangements of inhibiting water flow until the elevator recall function has occurred.

A heat detector is required to be installed within 2' of any sprinkler head associated with shutting down the power to an elevator (NFPA 72 2010 ed. 21.4.2*). It is important to shut down the elevator power prior to the release of water from a sprinkler head since water and electronics do not mix.  This is the reason the heat detector is required to be set to a lower temperature setting and higher sensitivity setting than the sprinkler head (NFPA 72 2010 ed 21.4.1*). With that said, a heat detector is not required if the sprinkler head is located within 24" of the elevator pit floor since there is typically not any electrical components located in this area.


There are three common methods to shutting down the main elevator power prior to water flowing from a sprinkler head in the shaft or elevator machine room.



#1) The most economical method is to use a waterflow switch.  Upon activation, the waterflow switch would cause an alarm at the FACU (Fire Alarm Control Unit) as well as activate the shunt trip breaker causing the power to be interrupted.  Make sure you follow NFPA 72 2010 ed 21.4.3*.  This code section states that if using waterflow or pressure switches to shut down elevator power, the use of a time delay shall not be permitted.

#2) This is the most common method.  By use of a fixed temperature rate of rise heat detector located within 2' of each sprinkler head in the shaft, hoistway or elevator machine room.  The heat detector shall be set to a lower temperature than the sprinkler head and when activated, will cause an alarm at the FACU and shunt the breaker associated with powering the elevator.

#3) Use of a pre-action system.  These systems would have supplemental fire detection devices installed in the same areas as the sprinkler heads.  Make note that the detection devices should be heat detectors.  Once on of the heat detectors have been activated, it would tell the pre-action control panel through program mapping to open a valve control by a solenoid.  Once the valve is open, water would then fill the sprinkler system piping in the elevator hoistway and elevator equipment room.  At the same time, the heat detector would also trip the shunt breaker thus shutting down the elevator power.  If a fire really is present in these areas, it would eventually fuse the sprinkler head and release water to the affected area.

Keep in  mind that heat detectors are to be used for shutting down power to the elevator and not smoke detectors.  Smoke detectors associated with elevators are to be solely used for designated elevator recall, alternate elevator recall and to activate the elevator hoistway smoke relief equipment.

Notifier by Honeywell

Notifier offers a great arrangement of fire alarm and life safety products.  Be sure to check out this
video courtesy of www.notifier.com.  At www.notifier.com you will also be able to locate cutsheets, data sheets, calculations, specifications and other documentation for their product line.


.

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Rectifier to Convert AC to DC

Sometimes in our industry, there is a need to convert volts AC (alternating current) to volts DC (direct current).  

Diode Rectifier for Fire Alarm
Diode Rectifier for AC to DCYou may run into this scenario when using a CCTV power supply with an AC (alternating current) output but yet you have DC (direct current) cameras.  Instead of replacing the power supply you can make a diode rectifier.

Please note that you can purchase these pre-made from stores like ADI or Frys.

A diode rectifier is a simple contraption made up of 4 diodes placed in a specific order.  This will allow you to connect an AC source on one end yet get a DC source out of the opposite.  In the picture below you will see how to place the diodes in order to achieve this.

Another simple way to think of it is the transformer that comes with your typical fire alarm control panel is rectified.  You connect 120 volts AC (alternating current) to the input and get 24 volts DC (direct current) out of the output.  The transformer is stepping the voltage down from 120 to 24 and the rectifier is converting the AC voltage to DC voltage.

Pretty slick right?

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Wednesday, March 18, 2015

Pre-Wire for ADA Adaptability in R2 Occupancies

What does it mean to pre-wire for future ADA adaptability?

The International Fire Code or IFC is where we look to find out what fire alarm requirements to follow when designing systems.  Specifically Chapter 9 "Fire Protection Systems".  If we dive deeper into section 907, we are informed as to what is required for each occupancy group.

For this article, we will be reviewing the requirements for an "R-2" occupancy.  As defined in the International Building Code or IBC, an R-2 group occupancy consists of: "occupancies containing sleeping units or more than 2 dwelling units where the occupants are primarily permanent in nature, including: Apartments Houses, Boarding House with more than 16 occupants, Convents, Dormitories, Fraternities and Sororities, Hotels (non-transient), Live/Work units, Monitories, Motels (non-transient), Vacation timeshare properties."

Since this article revolves around the requirements to pre-wire for future visual alarms, we will stay away from discussing the initiating side of the code.  Full requirements for an R-2 occupancy.

International Fire Code Section 907.5.2.3.4 Pre-Wire for Group R-2


Section 907.5.2.3.4 states "In group R-2 occupancies required by section 907 to have a fire alarm systems, all dwelling units and sleeping units shall be provided with the capability to support visible alarm notification appliances in accordance with Chapter 10 of ICC A117.1.  Such capability shall be permitted to include the potential for future interconnection of the building fire alarm systems with the unit smoke alarms, replacement of audible appliances with combination audible/visible appliances. or future extension of the existing wiring from the unit smoke alarm locations to required locations for visible appliances."

This is a major upgrade in comparison to a group R-1 occupancy such as Hotels and Motels.  In these facilities, the code gives us parameters as to how many rooms with visible alarms are needed based on the total quantity of sleeping units.

"So what does all this mean?"

In basic terms all living spaces within a group R-2 occupancy must contain the necessary wires, raceways and boxes to support the ability to upgrade to audible and visual notification throughout. ADA aside, our design must provide at least 75 dB in all areas of the quest room.  On top of this, your jurisdiction may now be requiring the fire alarm occupant notification to produce a 520Hz low frequency tone in all sleeping areas.  Find out more about 520Hz requirements.

A lot of fire alarm designers are confused to the actual requirements of this code section.  To be clear, it is the intent of the code to have a fully functional low frequency audible occupant notification system that can be upgraded with visual alarms without cutting walls, adding boxes or running new conduit.  All of the necessary wire or a conduit raceway must be in place to all living spaces, sleeping rooms and bathrooms within each living space.  As stated in the paragraph above, we need a minimum of 75 dB throughout the space.  To achieve this, it's typical to have a low frequency audible appliance in each sleeping room as well as the living space.  This design makes it easy to just swap out the low frequency sounder appliance for a combination low frequency and visual appliance. Don't forget that you will need a box and wire to each restroom within the guestroom.            

ADA section 4.28 "Alarms" gives us the requirements for visual appliances within ADA compliant areas.  Pay close attention to section 4.28.4 "Auxiliary Alarms" Units and sleeping accommodations shall have visual alarms connected to the building emergency alarm system or shall have a standard 110-volt electrical receptacle into which such an alarm can be connected and a means by which a signal from the building emergency alarm system can trigger such an auxiliary alarm.  When visual alarms are in place the signal shall be visible in all areas of the unit or room. Once a group R-2 living unit is upgraded to meet ADA requirements for visual alarms, you will need a low frequency audible tone of at least 75 dB throughout as well as visual alarms in all areas of the living unit.  This includes restrooms.

Side note: NFPA 72 2013 Table 18.5.5.7.2 informs us of the candela rating required visual appliances installed in  sleeping areas.

Distance from the ceiling to the top of the visual appliance lens:
> or = to 24 inches = 110 Candela
< 24 inches = 177 Candela

This standard was put in place as smoke migrates to the ceiling in the event of a fire.  It is common sense that a more intense strobe flash would be required to shine thorough the thicker smoke found closer to the ceiling and still have the ability to awake a sleeping occupant.  This is why we are required to install a 177 candela strobe when located less than 24" from the ceiling.

Best installation method to accomplish ADA adaptability for Group R-2 occupancies.


Run a trunk run down the corridor with Notification Appliance Circuit (NAC) loops as well as a Signaling Line Circuit (SLC) pulled into a J-Box within the closet of each living unit.  It is best to pick the closet that contains the unit's breaker panel.  From this J-Box pull your notification circuit loop through all appliance locations.  In the event the room needed to become adaptable, simply splice your incoming/outgoing NAC loop through in the J-Box.  This way the notification field wiring loop within the living unit is separate from the rest of the existing building NAC circuits.  Install a single output remote power supply listed for fire within the closet and power up with a dedicated 120 AC circuit.  Use the SLC in the closet to install an addressable smoke detector and control module to protect and activate the power supply.  See the example layout below:


Group R-2 ADA Adaptability for Fire Alarm


Now keep in mind that these audible / visual notification appliances will need to activate via general alarm, floor alarm or an alarm from within the unit itself.  To activate the notification appliances from within the living unit, you could either install addressable system smoke detectors or connect addressable mini modules to the 120 VAC UBC smoke alarms.  The detectors or modules would activate the control module connected to the power supply as well as indicate a supervisory condition on the fire alarm control unit (FACU).

Tuesday, March 17, 2015

Are Low Frequency Sounders Required by Your AHJ

520Hz Low Frequency Sounders 

"Effective January 1st 2014, audible appliances provided for the sleeping areas to awaken occupants shall provide a low frequency alarm signal that complies with the following:  (1) The alarm signal shall be square wave or provide equivalent awakening ability.  (2) The wave shall have a fundamental frequency of 520 Hz +/- 10 percent."

We got a glimpse of the future requirement in the 2010 Version of NFPA 72 section 18.4.5.3 page 102.  Here we could see that come January 1st 2014, there would be a requirement for fire alarm designers to use a 520Hz square wave low frequency sounder within all sleeping areas.  There have been multiple studies performed that validate the belief that a 520 Hz low frequency audible tone will have a greater chance at awakening a sleeping occupant.  The lower frequency also has greater chances of awakening people whom are intoxicated or hard of hearing.

Lets fast forward to the year 2013.  NFPA 72 version 2013 notes the same requirement in section 18.5.4.3 page 108.

Click to listen to a 520Hz Low Frequency sound file.  Or a 3KHz tone typically used prior to 520Hz requirements.

Now, here we are in the year 2016 and yet not everyone is following this standard.  You may ask yourselves why is our AHJ or authority having jurisdiction not requiring our fire alarm installation company to install the new 520Hz low frequency sounders for sleeping areas.  Keep in mind that the particular state you install fire alarms in may have an older code adopted.  Click to learn the difference between fire alarm codes and standards.

How do you know if your state or region is requiring 520Hz low frequency sounders?


The International Fire Code or IFC 2012 edition chapter 80 as well as the International Building Code or IBC 2012 edition chapter 35 both reference NFPA 72 2010.  With this said, you will need to find out if your jurisdiction has adopted the 2012 or newer version of the IBC or IFC code.  Better yet, System Sensor has provided a detailed map of the States and Regions currently adopting this code.  See below:

Map for 520 Hz Low Frequency Sounders

Thursday, March 12, 2015

Help Out Your Local Fire Fighters With a Dry Riser Now!

Dry Pipe Automatic Sprinkler Systems

Fire fighters are there to help you. When a fire breaks out they are rushing out to the fire to stop it before it can cause too much damage. Help them out by getting a dry riser. The dry riser is something that can be fitted into your building to help fight fires as soon as they break out. The outlet that exists outside the building can aid fire fighters further by making sure that they have a source of water they can use.

Dry Sprinkler Pipe System - How It All Works

Fire Sprinkler HeadThe dry riser works on the principle of compressed air. Compressed air is what differentiates it from the dry riser’s counterpart; the wet riser, which utilises water-filled pipes. The compressed air works by pressing the valve shut that prevents the water from entering the pipe. Once the air is released the valve opens up and the water can shoot through the pipes. 
At the end of the pipe is a sprinkler system. Sprinklers open up when a fire has been detected. Naturally, once the sprinkler opens the compressed air disappears and the water can then attack the flames. They may not necessarily be able to eliminate the fire, but what they can do is to make sure that it’s limited. Think of it as giving fire fighters some additional time to get to the scene of the incident.

Dry Pipe Sprinkler Systems - Help Your Local Fire Fighters!

Your local fire fighters are not always going to be in the best position when confronted with a fire. Due to rapid urbanisation, it’s now harder than ever to find a suitable water outlet that can provide the supply that’s needed to combat the most serious fires. Dry risers have to get their water from somewhere, and that comes in the form of an inlet valve. Fire fighters are able to attach their tools to this valve and draft the water from there.  
So you don’t have one of those things and they are forced to look elsewhere. Those extra minutes spent looking for a suitable supply of water could mean the difference between your property burning down and the structure being saved. Surely the desired outcome is going to be obvious here?

If you suspect the valve in your high rise has been tampered with ring the dryriser theft hotline.

Dry Pipe Sprinkler System - Where are they Fitted?


From a glance, it seems as if the dry riser system is quite vulnerable. Once the fire takes hold it can attack the pipes and cut off the supply. This is not the case at all. All of these systems are required by law to have their main pipes in a place that’s resistant to fire. Escape stairways are the number one places where these can be found. Note, these fire-resistant areas are not necessarily going to protect it forever. On the contrary, sooner or later the fire will burn through. 
Primarily, it’s to combat minor fires before they spread. If a major fire breaks out, or even worse an explosion, then nothing can be done until the fire fighters arrive.

Dry Pipe Sprinkler System - How Expensive Are They?


If you are looking to install one of these systems then one of the things you will be looking at is the price. Of course, the price is very important because nobody wants to invest a great deal of money in anything. Small businesses may also have trouble meeting large costs, so affordability is perhaps the most important factor. The good news is that companies are offering these systems at a cost-effective price. Regular deals are constantly being employed to encourage people to invest in these systems. 

No Battery Trouble on FACU or FACP

Remove Fire Alarm Battery Trouble

Before you read on please be advised that this tactic is only to be used in training FACU / FACP applications.  It is not the intention of Fire Alarms Online to provide this information to eliminate the need for battery backup on a FACU Fire Alarm Control unit, MNS Mass Notification System, RPS Remote Power Supply, etc.

Battery Trouble for Fire Alarm Control Panel

FACP is Normal without Batteries WOW!


There is a way to connect an FACU Fire Alarm Control Unit without backup batteries and have it remain in the normal condition.  Now like I mentioned above, this is typically only used if you have a training and or demonstration FACU that you travel with.  You can also use this trick if you have a redundant FACU in your shop used for training (only if the system is not an approved life safety system for the site).

The backup battery charger on an FACP, FACU, MNS, RPS, etc. is always looking for 24VDC.  This is how it supervises the backup batteries.  In other words, this is how the fire alarm control unit knows that backup batteries are present.  The same terminals on the charger, also put out 24VDC in order to constantly charge the backup batteries so that they are always ready in the event of primary power loss.

FACU Backup Battery Requirements


Most jurisdictions require 24 hours of standby and 5 minutes of alarm for a horn/strobe system and 24 hours of standby and 15 minutes of alarm for a voice system.  See here for battery backup calculations.

With the use of one simple diode, you can accomplish this feat.  Simply place the Anode (+ Solid Black) side of the diode into the non-resetable positive 24VDC power output on the FACU / FACP.  Now place the Cathode (- Stripe) side of the diode into the positive terminal of the backup battery charger.

How this works:  Think of a diode as a one way gate.  Electrical current can flow through it in only one direction.  So this trick is actually quite simple.  The diode is providing a positive current path from the +24VDC output on the panel FACU / FACP and into the + terminal of the battery charger thus tricking it into believing there are backup batteries in place.  The reason for the diode is very important.  You need to remember that the battery charger puts out 24VDC as well.  With that said, we need to block that power from coming back into the +24VDC output on the FACP / FACU.  Here is a picture to help explain this trick on how to keep an FACP / FACU in the normal condition without backup batteries.


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Voltage Drop for Fire Alarm Systems

Fire Alarm Voltage Drop Calculations

All electrical conductors include a small amount of resistance.  This resistance increases if the length of the conductor increases or or the conductor size decreases.  Think of blowing air through a hose. If the hose diameter decreases and or the length increases it would be harder to blow through.  You can also think of freeway traffic as resistance.  The freeway is the conductor.  The wider the freeway, the faster and smoother you travel.

Fire Alarm Voltage DropAs electrical current flows through the conductor it will experience a decrease in voltage between the source (starting point) and at various points along the conductor path.  Another example to look at is the voltage drop in a 1000 foot run of 16 AWG wire would be greater than that of a 1000 foot run of 12 AWG.  This is simply because a 16 AWG conductor is smaller in diameter than a 12 AWG conductor.

Fire alarm equipment LISTED to the standards of the National Fire Protection Association and Underwriters Laboratories (U.L.) is tested to determine if can operate properly at 85% of the rated nameplate voltage.  This limit was set in place to make sure the circuit can deal with a "brownout" condition or a possible voltage drop which might result from excessive resistance in the system wiring.

As required in the CFC (California Fire Code), fire alarm designers are required to prepare voltage drop calculations for the notification appliance circuits (NAC) as part of the design.  These voltage drop calculations must be included in the submittal plans and specifications.  This is to assure that the devices on the system are supplied with electrical power within the operating voltage range.

You as a designer can use several different methods to calculate voltage drop on a fire alarm circuit. One method calculates the actual voltage drop for each length of cable and device within the circuit and the other calculates the overall voltage drop.  Either method will have slightly different results but should be acceptable by your local AHJ (authority having jurisdiction)

The suggested maximum allowable voltage drop on a fire alarm circuit is 10% or the voltage drop included in the fire alarm control panel installation guide, whichever is less.

"Lump Sum Method"


Step #1)  Take the total current of the circuit.  You can achieve this figure by adding up the current draw of each device on the circuit.  This will represent "A"

Step #2)  Measure out the length of the circuit in feet.  Do not double the distance of the circuit for 2 wire loops unless you want to use a multiplying factor of 10.8 versus 21.6 (see step #3).  This will represent "L"

Step #3)  Use a multiplying factor of 21.6.  This number represents the resistivity of copper conductors.  This is a constant used in the formula.

Step #4)  Find the Circular Mils for the particular gauge wire you are using.  This can be found in the National Electrical Code (NEC) chapter 9 table 8.  #14 AWG is 4110 and #12 AWG is 6530.  This will represent "C.M".

A x L x 21.6
-------------  =   VD
C.M.

Example

.356 x 450' x 21.6
-------------------   =   0.530 Volts Dropped
6530

To find the percentage of voltage dropped do the following:
0.530 / 24 = 0.022
0.022 x 100 = 2.2
= 2.2% Voltage Drop

Now remember you can also perform this calculation for each individual length of wire and device on the circuit.  This is known as the "point-to-point" method.  This is a better way to perform the calculation as it gives you a chance to really break down the circuit and pin point exactly where a circuit must end do to voltage drop.  Simply use the above formula for each wire run and add the voltage drop totals for each circuit section together for the total voltage drop.  Then divide by the source voltage (in this example we will use 24VDC) and then multiply by 100 to come to a total voltage drop percentage.

I will be adding info in the near future on the calculations for the "point-to-point" method using Ohm's Law

If you are interested in taking the NICET CBT exam for fire alarms, then we have you covered! We are now selling our CBT Levels 1 - 3 practice exam DVDs.  These DVDs are packed with tons of NICET CBT practice exams along with all code references as to where to find the answers.  We have also supplied the DVDs with all of the necessary NICET applications, CBT calculator demonstrations, links and more.  If you need more information, feel free to send an email.  You can find the link to purchase our DVDs on the top left section of each page on this site.

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Magnetic Door Holders and Battery Backup with FACU

Dropping Door Holder Power with Loss of AC Voltage

When designing a fire alarm system you may come across the need for magnetic door holders.  There are no codes nation or state wide that require doors to be held open.  With that said, magnetic door holders are used as a convenience to hold doors open during normal operation.  If a customer wants to hold open a door along a non fire rated wall then they can prop it open.  Now if the customer wants doors along a fire rated wall to be held open then they must use fire rated doors and magnetic door holders tied into the building fire alarm system.  Make sure you understand the correct smoke detector spacing for the activation of smoke doors.

PR-1 Interface Relay for Fire AlarmI wanted to write this post to assist installers and system designers with a practice that will help eliminate the need for larger fire alarm system back up batteries to achieve 24 hours of standby and 5 or 15 minutes of alarm.  If the building loses 120 VAC power, the fire alarm system must switch over to backup batteries calculated to handle all of the devices tied to the system.  Door holders draw a lot of current and quickly add to the size of batteries required to properly backup a fire alarm system.

Since magnetic door holders perform their intended function with the loss of power, it is common to install a PR-1 interface relay to drop them out in the invent of AC power loss.  Simply power up the PR-1 interface relay with the AC power at the FACP / FACU or RPS (remote power supply) and break the door holder power circuit switch leg through the N.C. (normally closed) contacts on the PR-1 relay.  If the AC power to the FACU or RPS is lost, the PR-1 relay will change state and drop power to the field magnetic door holders.

Keep in mind that magnetic door holders are self supervising so there is no need to install any end of the line power supervision modules.  Just in case that did not make sense, the door holders perform their intended function (close) upon the loss of power.  You would only need to monitor the power at the end of line if the devices on that circuit require power to operate.

System Sensor D4120 Tamper Troubles

System Sensor D4120 InnovairFlex Duct Smoke Detectors 

These conventional duct smoke detectors include a tamper switch feature that results in a trouble signal at the fire control panel when the duct detector cover has been removed or is not properly installed. If your System Sensor D4120 duct smoke detector is displaying a solid Amber LED, then this is the device's indication that the cover is either missing or not properly tightened down. Keep in mind that this trouble condition will also disable the System Sensor's detector test feature, which is activated using one of the following methods; the Push Button on the power board, the Magnet Test or Remote Test Stations.

System Sensor D4120 Duct Smoke Detector

If you are experiencing this trouble condition, ensure that the System Sensor D4120 duct detector cover of the device is properly aligned and the connecting screws are tightened firmly. When properly attached, a small pole on the cover should contact the bottom left terminal of the tamper switch and depress to contact a terminal on the underside of the cover, closing the tamper switch.