NFPA 72 2010 Code Book Secrets

Well the title says secrets but to be honest it really is public information.  However not too many readers are aware of it.  Check this out.  The 2010 edition of NFPA 72 National Fire Alarm and Signaling Code has a few items throughout the text that can help the readers better understand the changes and new layout.

• A vertical bar in the margin indicates that a change other than editorial has been made.
• A bullet indicates that one or more complete paragraphs have been deleted.
• A reference in parenthesis () following a paragraph indicates technical committee responsibility.
• A reference in brackets [] indicates exacted material from another document.

If you are interested in taking the NICET Test for "fire alarms" or "Inspection and Testing of Fire Alarms", then we have you covered!  We are now selling our CBT Levels 1 - 4 NICET practice test with preparation material.  This material is packed with tons of NICET practice test questions along with all code references as to where to find the answers.  We have also supplied the material 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 NICET Practice Test on the top left section of this site.

Fire Alarm Calculations

If you are preparing to take the NICET exam for Fire Alarm Systems, there are numerous fire alarm calculations you must understand in order to properly design a code compliant system.  These calculations can break down exact requirements for sound pressure (dB) levels, voice intelligibility, voltage drop on a circuit, back up battery sizes, candela settings and dB line loss for speaker circuits.  There are additional calculations however these are some of the most common and important so this article will concentrate on the following:

You can also download our Fire Alarm Calculation Tool here.

How to find the correct Candela Strobe to cover a given space

This is a very important measurement as it allows us to properly calculate the necessary candela power needed for a given space.  If you do not have NFPA 72 2013 edition tables 18.5.5.4.1(a) and 18.5.4.4.1(b) handy or memorized, this formula will save the day!

Take the selected candela (ex. 75 cd) and divide it by 0.0375
75 cd / 0.0375 = 2000
Now take the square root of 2000 to get a spacing of = 44.72136 feet.

If you consult NFPA 72 2013 tables 18.5.5.4.1(a) it shows a spacing of 45 x 45 feet and table 18.5.5.4.1(b) shows a spacing of 44 x 44 feet.

Voltage Drop Calculation

Step #1:  Find the total current from all of your field notification appliances.  If you consult the appliance's specification sheet, you will find the current draw for each setting.  For example, you have four appliances on the temporal high setting and they each draw 50mA or (0.050A).  If you add all four appliances together (4 x 0.050) you have a total current draw of   0.2A

Step #2:  Determine the to and from distance of the notification appliance circuit (NAC).  For this example, we will saw the NAC is 450 feet.  We have to double this distance to account for both conductors.  450 feet x 2  = 900 feet.

Step #3:  Now that we know the distance, we need to know what type of conductor we are using for the circuit.  For this example we will use a #12 AWG solid coated copper conductor.  Once this is determined, we will need to consult the Conductor Properties table 8 in the National Electrical Code or NEC 2011 (click the link to view a copy of the table).  This table can also be found in chapter 9 on page 721.   On the table, located the section at the top under coated.  Now follow the line down under ohm/kFT (ohms per 1000 feet).  Keep scrolling down until you reach the 12 AWG with a quantity of 1 since it is solid.  If you line the left and top rows up, you will see a resistance of 2.01 ohms for 1000 feet of conductor.

Step #4:  Since we do not have a distance of 1000 feet for a out circuit, we will need to break down this resistance according to our actual distance of 900 feet.  To do this simply divide 900 feet by 1000 feet sown as 900/1000 = 0.9.  Now multiply your resistance per 1000 feet (2.01) by your distance breakdown of 0.9.  2.01 X 0.9 = 1.809 ohms per 900 feet.

Step #5:  To determine the voltage at the end of the notification appliance circuit we need to use Ohm's Law.  Since we know know the total amps (0.2A) and the total resistance (1.809) we can now find the voltage.  I X R = E or Amps x Resistance = Voltage.  0.2 x 1.809 = 0.3618 volts.

Step #6:  To find the voltage drop subtract your answer found in step #5 (0.3618) from the starting voltage of 24 volts.  24 - 0.3618 = 23.6382 volts.

Step #7:  Sometimes you may be asked to know the voltage drop percentage.  To find this, take the voltage drop (0.3618 volts) divided by 24 volts and multiply it by 100.  This is shown as (0.3618/24) x 100 = 1.5075%

See more examples of voltage drop for NACs here

Resistor Calculations

Calculating Resistors in Series

If you come across multiple resistors in series with each other, simply add the resistor values.

Resistors in Series

Example:
R1 = 3.3k
R2 = 4.7k
R3 = 10k
Total Resistance = 18k

Calculating Resistors in Parallel 

Resistors in Parallel

1/Rt = 1/R1 + 1/R2 + 1/R3

R1 = 200
R2 = 400
R3 = 800

1/Rt = 1/200 + 1/400 + 1/800

If there is a common denominator for the bottom numbers use it by multiplying up both the top and bottom numbers in the fraction.

Example: the common denominator is 800.

Resistor R1 has a resistance of 200.  200 goes into 800 4 times.  Therefore R1 = 4/800
Resistor R2 has a resistance of 400.  400 goes into 800 2 times.  Therefore R2 = 2/800
Resistor R2 has a resistance of 800.  800 goes into 800 1 times.  Therefore R3 = 1/800

Now add the top numbers together (4 + 2 + 1 = 7) and place it on top of 800 like this 7/800.  Now take the reciprocal to make the fraction reverse to 800/7.  Divide 800 by 7 to get your answer of  = 114.286k.

Battery Calculations

Take the total standby current and multiply by 24 (hours for standby)
Take the total alarm current and multiply by (.083 for 5 minutes or .249 for 15 minutes of alarm)
Add the total of (standby current x 24) to (alarm current x .083 or .249)
Multiply the total of above by a safety factor of 1.2.  This gives you a 20% spare buffer.
Round up to required battery amp hour size.

dB Loss and Gain

Every time you double the distance from the audible appliance, you loose 6 dB.

Example:  If you have a speaker with 75dB at 10 feet, you will have 69dB at 20 feet and 63dB at 40 feet and so on at 80 feet, 160 feet......  Please note, these are not multiples of 10 feet!!!  These are broken down by doubling the distance from the last measurement.
Correct: 10 feet - 20 feet - 40 feet - 80 feet - 160 feet
Incorrect:  10 feet - 20 feet - 30 feet - 40 feet - 50 feet - 60 feet

If you double the power output of the appliance, you gain 3dB.

Example:  If you have a speaker tapped at a 1/4 watt with 75dB and you double the wattage to 1/2 watt, you will then have 78dB.

dB Line Loss Calculation

TLR = Total Load Resistance
TWR = Total Wire Resistance
TWR = Ohms/Foot X (Distance X 2)

12 AWG Ohm/FT is .00193
14 AWG Ohm/FT is .00307
16 AWG Ohm/FT is .00489
18 AWG Ohm/FT is .00777

TLR = (Voltage X Voltage) / Power
20 X Log (1- (TWR / TWR + TLR))

You cannot go over -1.5 dB

Are Your Aerosol Smoke Testers EPA Compliant

Smoke detector testing with aerosol

Seeing as smoke detector testing is a code mandated requirement to remain compliant, I will assume we all aware of aerosol smoke detector testing cans.  If not, these are the small cans of artificial smoke that utilize different types of propellants for the purpose of testing..... You guessed it, Smoke Detectors.  There is an important change on the horizon due to the EPA's "Significant New Alternatives Policy" or SNAP for short.   As of December 31, 2017, aerosol smoke detector testers that utilize HFC-134a as their propellant will no longer be manufactured.  

What do we do now?

Do not panic.  The rapidly approaching date of December 31, 2017 does not have any bearing on the physical use of smoke detector testers with the propellant HFC-134a as this is NOT a ban.  In fact the EPA has granted some manufacturers such as SDi Specialized Fire Products an UNLIMITED "sell-through" period for any and all existing stock.  The SOLO A4 Smoke Detector Tester will continue to be sold until its anticipated exhaustion date of late 2018.

Are there other products without HFC-134a available now?

The answer is yes.  For simple smoke detector tester can replacements to the Solo A4, we can recommend the three following products:

• The Smoke Sabre Smoke Detector Tester.  This product has been available since 2009, is approved by NFPA and contains absolutely no HFC-134a making it EPA Rule 20 compliant.  This product comes in a cut above the competition as it is silicone FREE.  The lack of silicone eliminates the concern of contamination and plastic compatibility.
•   The Smoke Centurion - This product is exactly like the Smoke Sabre, however it can be used as a hand held unit or in conjunction with the SOLO 330 aerosol dispenser.



SDi Smoke Centurion Aerosol Smoke Tester

• The new SOLO A10 (from what I have heard, should be available some time September 2017).  This unit was developed in partnership with Honeywell and utilizes their Solstice ultra-low global warming potential (GWP) propellant which is also non-flammable, HFC-134a and silicone free.  This unit will be available in two convenient sizes.   

SDi SOLO 365 Non-HFC Smoke Tester

If you are in the market for a non-aerosol smoke detector testing unit than you need to read up on the Testifire!  The first of its kind, Testifire is an electronic smoke/heat and CO detector tester.  Available in both Smoke/Heat and Smoke/Heat/CO versions, Testifire allows the user to test without aerosols using a patented smoke generation technology with no silicone.  The unit is Manufacturer approved, listed for testing, as well as NFPA and EPA Rule 20 compliant.

Another product coming very soon is the SDi SOLO 365 smoke detector tester.  This unit is used for smoke detector testing only unlike the Testifire.  The SOLO 365 utilizes the SOLO ES3 smoke cartridges providing a faster and cleaner test.    

Additional fire alarm related aerosols available through the EPA Rule 20

• The SOLO A7 non-flammable canned air has been granted a lifetime exemption from the EPA.
• The Smoke 400 aerosol used with the Trutest smoke sensitivity tester will continue to be available as it is not subject to the EPA Rule 20.  

In closing, make sure to inform your managers, technicians, end-users and AHJs of this important change.  As we approach the late part of 2018, these products will become increasingly harder to come by.  Make sure you stock up now or insure your company is migrating to one of the EPA Rule 20 compliant testers mentioned above.   If you have any questions or would like to discuss your experiences with these products, please feel free to join our Facebook Group.  

NICET Testing with Learning Disabilities

One of our Fire Alarms Online Facebook Group members recently asked recently if NICET provides any accommodations for persons with learning disabilities seeking certification.  After contacting NICET's testing division directly, I found that this is in fact a service they provide under Policy #19.

In order for an applicant to request special accommodations under the Americans with Disabilities Act (ADA), he or she must submit a determination document from their medical practitioner stating their past and present diagnosis.  In addition to this step, the applicant must also complete a request for special testing accommodations form with a NICET Technician application for review (Download Link Below).  From there, NICET will set the applicant's ADA status and the examination is scheduled accordingly.

NICET claims that if the applicant requires double time, half time, a reader, a separate testing room, etc; they will make arrangements as needed.

Below we have included a download link for the NICET's ADA form that must be completed and faxed to NICET's testing division (703-682-2756) prior to scheduling your examination with a Pearson VUE testing facility.

Download files with the links below.

NICET ADA Form

NICET Technician Application

Smoke Detector above Fire Alarm Control Unit FACU

A question we see coming up more often is in regards to smoke detection above fire alarm control units.  The specific questions is, "Are you required to install a smoke detector above the fire alarm control unit (FACU) or fire alarm control panel (FACP)?".

Simply put the answer is YES and can be supported by the language found in NFPA 72 2022 edition section 10.4.5. (page #74).  This sections states the following:

"Unless otherwise permitted by 10.4.5.1 or 10.4.5.2, in areas that are not continuously occupied, early warning fire detection shall be provided at the location of each fire alarm control unit(s), notification appliances circuit power extenders, and supervising station transmission equipment to provide notification of fire at that location by one of the following means:

(1) An automatic smoke detector at the location of each control unit(s), notification appliance circuit power extender(s), and supervising station equipment.

(2) An automatic heat detector where ambient conditions prohibit installation of an automatic smoke detector."

Also note there is an Annex section related to this reference.  A.10.4.5 states that the equipment to be covered by this automatic smoke detection is a fire alarm control unit that is used to notify occupants and responders of a fire.

Here are a few other key items to keep in mind when dealing with this topic:

• The term Fire Alarm Control Unit (FACU) does NOT include annunciators or addressable devices.
• If the area where the FACU is located is continuously attended, a smoke detector is NOT required.  Keep in mind this is not intended for lobbies or offices where there are occupants coming and going throughout the day.  This is intended for areas such as lobbies with 24/7 security and security rooms where at least one guard is in attendance at ALL times.
• If the area where the FACU is located has full coverage smoke detection, then an additional smoke detector dedicated to the FACU is NOT required.
• If the single smoke detector intended to protect the FACU per 10.4.5 does not cover the entire space where the control equipment is located, then additional smoke detection is NOT required.

Now here is were it may become confusing for the designer or AHJ.  Section 10.4.5 as well as A.10.4.5 clearly state that the FACU to be protected is a control unit that is in place to notify occupants and first responders of a FIRE.  As you may or may not be aware, there are additional systems we deal with in this industry known as Dedicated Function Fire Alarm Systems.  

Building Fire Alarm System vs. Dedicated Function Fire Alarm System

As defined by NFPA 72 2022 edition Section 3.3.118 (page #29)

Building Fire Alarm System.  A protected premises fire alarm system that includes any of the features identified in section 23.3.3.1 and that serves the general fire alarm needs of a building or buildings and that provides fire department or occupant notification or both.

Dedicated Function Fire Alarm System.  A protected premises fire alarm system installed specifically to perform emergency control function(s) where a building fire alarm system is not required.  

Here is the code section that indicates when a Dedicated Function Fire Alarm Alarm Systems can be installed in place of a building fire alarm system per NFPA 72 2022 edition section 23.3.3.2.1. 

"In facilities without a building fire alarm system, a dedicated function fire alarm system shall be permitted and shall not be required to include other functions or features of a building fire alarm system."

The two most common dedicated function fire alarm systems typically used are:

• Dedicated function sprinkler monitoring system:  This is a system installed when a particular building does not require a building fire alarm system BUT still has an automatic fire sprinkler system employing more than 6 heads.  Example could be a small strip mall (Group M) with under 100  occupants but more than 6 automatic sprinkler heads.  Although this system is not in place to notify occupants or responders of a fire, a smoke detector is required above the panel since this system is in place to monitor the sprinkler system.  Per NFPA 72 2022 section 10.4.5 a smoke detector is required to protect "supervising station transmission equipment".

• Dedicated function elevator control system:  This is a system installed strictly and specifically to control the emergency functions of an elevator such as elevator recall and shunt trip.  These systems will typically have your elevator lobby/equipment room smoke detectors, heat detectors, relays and modules to perform the emergency control functions found in NFPA 72 2022 chapter 21.  Note this system would not be required to be monitored as it is not in place to monitor the status of an automatic sprinkler system.  In this case a smoke detector is NOT required above the control unit as it is not monitored nor is it in place to notify occupants or responders of a fire.

FACU Smoke Detector Installation Location

NFPA 72 2013 Smoke Detector Mounting Diagram

Pay attention to your applicable code as the installation location of this smoke detector changed
between NFPA 72 2010 and 2013 editions.

NFPA 72 2010 (A10.15 #1 and #2) state if the ceiling height is 15' or less, the smoke detector shall be installed on the ceiling or wall within 21' of the centerline of the FACU.  If the ceiling height exceeds 15', the smoke detector should be installed on the wall no more than 6' above the top of the FACU.

NFPA 72 2013 (A10.4.4) states the smoke detector shall be installed in accordance with section 17.7.3.2.1.  Section 17.7.3.2.1 states "Spot-type smoke detectors shall be located on the ceiling or, if on a sidewall, between the ceiling and 12 inches (300 mm) down from the ceiling to the top of the detector."

Relationships with Your Local AHJ

In the fire alarm industry we have National Codes and Standards as well as Local Ordinances to follow.  To name a few, the National Codes/Standards are the IBC (International Building Code), IFC (International Fire Code), NFPA 72, and NEC (National Electrical Code).  Now, while some of the literature in these references may be crystal clear, others are often clear as MUD!  This is why you always hear the term "Up for Interpretation".  This is an easy way for local AHJs (Authority having Jurisdiction)  to put their own spin on these references.  If you have been in the fire alarm industry long enough, then you will understand that it can get very frustrating when dealing with an AHJ that is out of line.  In these situations you must be a courteous professional that knows the codes and can stand their ground.

If you are in the fire alarm business and directly handle the design of systems, then you will more than likely deal with an AHJ on multiple occasions.  I suggest being prepared.  If you are submitting a system for review, make sure you bring the National Code references pertaining to your design. Also it is very wise to research the City's local ordinances to see if they have adopted any codes that may be more stringent than the National codes we base our systems on.  A while back when I first started designing systems, I came across a medium sized office building with a large warehouse used by a landscaping company.  With a B type occupancy and over 20 sprinkler heads, the National Code required a dedicated function sprinkler monitoring system.  I should also mention that there were less than 100 persons on floors other than the level of main egress with a total occupant load of less than 500.  With that said, only one horn would be required near the FACU.  Now the City where this building was located, had a local ordinance to require full occupant notification throughout for any B occupancy structure containing more than 100 sprinkler heads.  This was my fault for not checking with the City prior to my design.

I strongly believe that we learn from our mistakes and this particular one has taught me to really research all aspects of the design criteria before presenting a finished product to the client, FPE or AHJ.

Now in some cases, the AHJs are just plain out of line.  Fire officials typically have the attitude that more is better and in some cases they are correct.  Coming from the contracting side of the industry, I would love to see more stringent codes enforced that mandate additional equipment.  However, I also understand that money talks.  To the fire department, money is not the driving factor of their decisions.  Their job is not to help save the end-user money rather it is to instruct them on what their buildings require in the event of a fire emergency.  Us as the designers and contractors are the middle man for the clients.  It is our job to perform value engineering and get the customer a top notch system that meets all National and Local codes all without breaking the bank.  If you ever come across a hard nosed fire prevention plan checker or inspector, don't lose your cool!  This will only make matters worse and in no way help you achieve a signature on your ROC (record of completion) or permit.  In these cases I always like to ask the inspector or plan checker the following: "Can you please reference your requirement in the code so that I can apply it to my next design?".  In more cases than not, they will have to get back to you because they don't have the answer.  This is the easiest way to get them to back off.  By asking for this information, you don't sound like you are second guessing them and that you are actually relying on them for assistance.  Once they realize their requirement is not in the National or Local codes, you should be on the correct path to moving past any discrepancies.

Another great practice when designing systems for your clients is to hold pre-application meetings at the fire prevention office.  This is an excellent opportunity to lay all of your cards on the table.  Make sure to represent your clients concerns and make sure to document everything.  This makes sure that everyone is on the same playing field and shows your client that you are looking out for their best interests.

Designing fire alarm systems can be very fun and rewarding if you know what you are doing.  Make sure to become familiar with all applicable codes and regularly attend code seminars to stay ahead of the curve.

NFPA 72 Tabs for NICET Exam

Preparing for the NICET exam can be frustrating, intimidating and exhausting.  When you are feeling the pressure to pass this exam, keep one major thing in mind, "It's not necessarily what you know or how much you can store in memory.".  The key to NICET along with any other timed test is time management.  If you can learn a few time saving tricks, this can drastically help reduce anxiety during the examination as well as assist you in gaining additional confidence to push forward.  Since NICET allows you to bring your own references into the testing facility, you have a huge advantage on your side!  You can use preemptive measures to prepare your books weeks before you even step foot into the facility on exam day.  

NICET Insider tip:  Keep in mind that all reference materials brought into the NICET testing facility MUST meet the criteria found on NICET's website.  The NFPA 72 Handbook is NOT an acceptable alternative to the allowable references!

As stated above, its not what you can remember rather how well you can prepare for this exam by learning to properly navigate the reference material and turn to the correct pages to locate the needed information as quickly as possible.  Now obviously there are going to be answers you know off the top of your head and that's great!  These immediate responses will allow you to ultimately bank additional time for the questions you do not know so well.  The goal of this technique is to rapidly respond to any given question with the knowledge and confidence to grab the right reference and turn to the correct page without any delays.   Tabbing your code references is essential to success.  Remember that NICET does not allow any non-permanent tabbing of your personal code books.  This means that your code book tabs will need to be permanently attached via tape or glue.  You cannot use loose sticky notes.  They will be removed once you enter the NICET testing facility.

These are the Sticky Tabs we Recommend

How and where to tab your NFPA 72 code book

A lot of future NICET exam students ask me where to place the tabs to give them the best advantage.  To be honest the tabs are completely up to you as well as what NICET level you are testing for.  What I can tell you is there are a few tabs that are in my opinion necessary and applicable to all levels and exams.  These tabs would include each chapter, the different Annex sections and tables.  I also provide tabs for Annex "A" chapters 17 and 18 as there is a lot of valuable information in the Annex for Notification Appliances as well as Initiating Devices.

The tabs themselves are not exactly large enough to descriptively write out what they represent so its up to you to come up with a system that works for you.  I recommend just using numbers for the chapters, letters for the Annex, T for tables along with some sort of numeric or alphabetic system for what it represents and TOC for the table of contents.     Below is a breakdown of the reference tabs I recommend for your NFPA 72 2022 edition during the NICET exam:

• TOC - Table of Contents page 15
• DEF or 3 - Definitions found in Chapter 3 page 20
• DOC or 7 - Documentation page 34
• FUN or 10 - Fundamentals page 68
• CKTS or 12 - Circuits and pathways page 76
• TEST or 14 - Inspection, Testing and Maintenance page 79
• T-I(vis) - Table for VISUAL Inspection Frequencies page 80
• T-I(fun) - Table for FUNCTIONAL Inspection Frequencies page 84
• INIT or 17 - Initiating Devices page 97
• HD - Heat Sensing Detectors page 99
• SD - Smoke Sensing Detectors page 100
• AIR - Air Sampling Detectors page 102
• DOOR - SD for Door Releasing Service page 104
• NAC or 18 - Notification Appliances page 109
• AUD - Audible Characteristics page 110
• VIS - Visual Characteristics page 113
• T-VIS - Table for Visual Spacing page 113-114
• CONT or 21 - Emergency Control Function Interfaces page 117
• PPFAS or 23 - Protected Premises Fire Alarm Systems page 120
• ECS or 24 - Emergency Communication Systems page 129
• SUPER or 26 - Supervising Station Alarm Systems page 142
• PUBLIC or 27 - Public Emergency Alarm Reporting Systems page 155
• HOUSE or 29 - Single and Multiple Station Alarms and Household FAS page 166
• A - Annex A page 173
• A17 - Annex for Chapter 17 page 210
• T-SD/HD - Tables for Detector Spacing page 212-215
• A18 - Annex for Chapter 18 page 227
• B - Annex B page 282
• C - Annex C page 322
• D - Annex D page 323
• INDEX - Document Index page 351

Now this is very important!  The placement of tabs in your NFPA 72 code reference is everything.  I recommend placing the chapter and Annex tabs along the right edge of the document in a staggered order so they are easy to read and access at any time during the exam.  The tables and other tabs are highly recommended to run along the top border of the document.  This will reduce clutter and increase efficiency though organization.  

Lastly if you must include additional tabs for individual section support, I highly recommend placing the tab along the edge of the document that is closest to the needed text.  This way when you open the code book to that section, the tab will quickly guide you directly to where you need to be.  

If you need additional help with the NICET exam process I suggest you join our Facebook group