Tuesday, September 8, 2015

NICET Inspection and Testing for Fire Alarm Systems

Inspection and Testing of Fire Alarm Systems

If you are involved with the maintenance and periodic testing of fire alarm systems, now is a better time than ever to become NICET certified.  As you may be aware, NICET recently introduced a secondary certification field for the inspection and testing of fire alarm systems.  This was designed to give personnel the ability to become certified for specifically inspecting and testing fire alarm systems without the need to learn all of the other criteria involved with the standard NICET Fire Alarm Systems exam.

Why become NICET certified?

With NICET being the benchmark for professional certification as well as this new certification field becoming increasingly popular, its time to get on board.  It is only a matter of time before fire alarm specifications start demanding this certification for all personnel involved with the testing and maintenance of their fire alarm systems.

NICET is helping out in a HUGE way. 

Now if the above does not get you to visit the NICET website, maybe this will.....  NICET is now looking to help out their loyal certificate holders by offering some new crossover credit.  This week NICET revised their website to include a page dedicated to the test credits for the new Inspection and Testing of Fire Alarm Systems exam.  In basic terms, it states that if you hold a current level 2 or higher in Fire Alarms Systems, you can bypass the testing process of the new exam.  See the chart below for a in depth breakdown:

Please note there are still some things you need to do one your end to receive your certification.  This includes the submission of

  • NICET Test Application Section 1 and 2
  • NICET Work History
  • NICET Performance Measures
  • NICET Verifier Data
  • Submit a Payment of $140.00 to NICET for the Review of your Documents
The payment can be made online at NICET's website.  Make copies of all your documents and submit to NICET via email at evaluations@nicet.org.

I hope this information proves helpful and remember to keep pursuing NICET in your career.  This company's rigorous testing and background process insure you will always be placed with a solid fire alarm company.   

Saturday, September 5, 2015

Quickest Way to Locate Ground Faults on a Fire Alarm System

What is the worst service call you can possibly receive?  In my mind it is the infamous ground fault on a fire alarm system.  These can either be a quick fix (pending it's locked in and you are familiar with the circuit pathways) or a very time consuming correction.  If the ground fault is minuscule due to compromised wire insulation, water or vibration causing the ground fault to swing in and out, you could potentially be looking at a long day.

Note there are two types of ground faults.  

  • An absolute short to ground is caused by a portion of the conductor touching a solid earth ground.  This is the case with pinched our cut insulation, wires stripped back to far, strands of your conductor poking through tape, etc.  In all these cases, the actual copper of the conductor is touching physical ground.  
  • The other form of ground fault is commonly known as a "soft ground fault".  These faults are typically caused by moisture or compromised insulation where the copper is not necessarily touching ground however the insulation/voltage threshold is lowered and can be the cause of a ground fault.  Water can also be the cause by penetrating the insulation through hairline fractures and bridging the gap between the copper and ground.

How ground faults are determined by control panels and multi-meters

A fire alarm control panel uses an internal 12-24 volts DC to seek out ground faults on all connected circuits including power, SLC, IDC and NAC.  Most ohmmeters used for troubleshooting fire alarms systems have an internal battery with an output voltage of 1.5 - 3 volts DC (In the picture below, you will notice the analog ohmmeter I am using for this article puts out 1.628 volts DC).  In cases where the insulation/voltage threshold is below 12 volts but above 3 volts, the ohmmeter will not detect the ground fault.  If the ground fault does register on the ohmmeter, it will show some conductance to ground where a clean circuit will show infinite ohms or an open circuit.  With a soft ground fault present on the conductor, the ohmmeter will show a reading in the range of high killiohms (K) or milliohms (M).  Note the fact that these readings can be unstable and hard to decipher if the technician is not completely seasoned and experienced with their multi-meter.

DC Voltage Output of Analog Ohmmeter

The solution to quickly locating a soft ground fault on a fire alarm system.

In order to locate a soft ground fault as easily as the fire alarm control panel, we will need a ohmmeter that has a slightly higher output voltage than the factory range of 1.5 - 3 volts DC.  This higher voltage output will allow you to locate the source of the ground fault more quickly and accurately saving you a great deal of time in the field.  Once you know what conductor the ground fault is on, you can use the industry standard of breaking circuits in half until the fault is isolate to its source.

How to build your own high voltage output ground fault detection meter. 

Below I have outlined step-by-step instructions on how to build your own ground fault meter using materials found at any hardware store for around or below $30.00.

Fire Alarm Ground Fault Testing Equipment

Above is a picture of all the necessary equipment to build a very simple to operate fire alarm ground fault tester.  The equipment in its entirety is as follows:

  • 1 - Analog ohmmeter (roughly $15.00)
  • 4 - 9 volt Batteries (roughly $7.00)
  • 4 - 9 volt Battery Connectors with Flying Leads ($.49)
  • 1 - Set of Ohmmeter Test Leads ($6.00)
  • 1 - Heat Shrink Tubing (< $1.00)
  • 1 - Limiting Resistor (< $1.00)
  • 1 - Set of Velcro Straps ($5.00)

Equipment you should already have in your arsenal

Lets get started with the build!

Step #1:

Use your digital multi-meter (set to read current) to take a current draw of your analog ohmmeter.  To be more detailed, you need to find out the current used by the analog ohmmeter to read exactly zero Ohms or a dead short.  Move your positive test lead on the digital multi-meter to AMPS and turn the selection dial to DC Amps.  Now place the two test leads of the digital multi-meter into the test lead ports of the analog ohmmeter.  When done correctly as pictured below, your analog ohmmeter should show zero Ohms and your digital multi-meter will indicate the amps needed to show true zero.  In the picture below the digital multi-meter shows a reading of 0.016 Amps.  Remember this number for determining the limiting resistor value in.

Step #2:

In order to achieve the higher output on our new analog ohmmeter, we will be using the four 9 volt batteries in series. Remember when batteries are connected in series the voltage doubles and the Ah remains the same.  So in the case of four 9 volt batteries in series, we will achieve 36 volts DC.  Start out by stripping and connecting the four 9 volt battery connectors with flying leads in series.  Once connected, I highly recommend a solid bond via solder finished off with a clean heat shrink tubing.  See the below pictures for examples.

9 volt battery connection in series

9 volt battery connection in series

Step #3:

Now that we know what amount of voltage we have with our four 9 volt batteries in series (36 volts) as well as the current used to read absolute zero on the analog ohmmeter (found in step #1), we can use Ohm's Law to determine our limiting resistor value.  Ohm's Law states that E (volts) / I (current) = R (Resistance).  In this case 36 volts / 0.016 amps = 2,250 or 2.25K.  For the purpose of this article, I will be using a 2.2K resistor.  When you attempt this project, you may need to slightly increase/decrease the value of your limiting resistor in order to read absolute zero.  Remember, lower value resistors will move your analog ohmmeter needle closer to the right (0 ohms). 

Step #4:

We will now need to insert this limiting resistor in series to the negative test lead of our analog ohmmeter.  I recommend cutting the negative test lead 5 - 7 inches away from its meter connection side.  Once the lead is cut, splice the resistor in series, solder the connections and finish off with heat shrink tubing.  IMPORTANT, make sure the limiting resistor is placed between the analog ohmmeter and the 36 volt battery connectors.  See below picture.

resistor in series with 9 volt battery connectors

Step #5:

This next step is preference as you can clean up the wire connections anyway you see fit.  For this article, I just taped them up.  Once you get your ground fault meter built, you will want to play with some different ideas that will insure longevity and ease of use in the filed.  With the negative test lead disconnected from the analog ohmmeter, connect all four of your 9 volt batteries to the connectors.  Once connected, use your digital multi-meter to verify 36 volts insuring your connections are correct.

Step #6:

Now that you have verified the correct output voltage, connect the negative test lead to the analog ohmmeter.  With the ohmmeter set to Ohms, short the test leads together.  You should get absolute zero.  In the picture below, I have the 36 volt battery pack Velcro strapped to the back of the analog ohmmeter.  You will see both test leads are shorted and the ohmmeter is reading absolute zero.

Ohmmeter reading absolute zero dead short

The picture below shows the new output voltage once your fire alarm ground fault tester is complete.  If you remember from the earlier in the article the original analog ohmmeter put out 1.628 volts DC whereas the new setup is showing 39.53 volts DC.

This 39.53 volts is a combination of the 36 volt battery pack as well as the internal battery within the analog ohmmeter.  This higher voltage will make locating a ground fault a lot easier as well as increase your accuracy tenfold.  Also note the output voltage is still low enough to not damage devices and appliances on fire alarm circuits.  Make sure when using this tester, you disconnect all circuits from control boards.  To locate a ground fault, look for continuity to ground on each circuit.  This new analog ohmmeter will show infinite ohms when the conductor is not exposed to an earth ground.  If the insulation is compromised and/or the copper is directly connected to ground the ohmmeter will indicate 0 ohms.  If a soft ground fault is present, the meter will fluctuate from infinite (left) towards zero (right).  This fine movement should allow you to track down circuits with faults in half the time.

Good luck with your build and be sure to let us know if this new fire alarm circuit tester helps you in your daily troubleshooting.

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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.

Make sure to join our Fire Alarms Online Facebook Group HERE.

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.

Elevator Recall and Shunt Trip Wiring Methods

We have created an easy to follow document for the proper wiring method with elevator shunt trip functions.  This document includes two methods both based on the supervision requirements of NFPA 72 2013 edition section A21.4.4.

Below is a sample picture of the document that is available for download on our Facebook Group.

It is important to remember that the wiring between the FACP/FACU and the ECID (Emergency Control Interface Device) needs to be supervised.  In one method below, we are using an addressable relay module (FRM-1) to operate the shunt trip breaker directly.  With this wiring method, only the wire to the FRM-1 (SLC) needs to be supervised.  This is obviously achieved through the SLC and addressing of the device.

In the alternate method, we are showing you how to properly wire up the equipment when the load of the circuit exceeds the rating of the FRM-1.  In this case you would need to install a PR-1 interface relay (rated for 10 amps).  Now that you have a PR-1 switching the shunt trip circuit, this becomes your ECID (Emergency Control Interface Device) and the wiring up to this relay needs to be supervised.  To save the cost of an additional addressable monitor module (FMM-1) we can switch out the FRM-1 with a FCM-1 (addressable control module).  By doing this, we can achieve supervision as well as activation of the PR-1 interface relay through one device.

Elevator Shunt Trip Wiring Diagram

Make sure to download the document and let us know your thoughts.