its listed sensitivity range, the green LED blinks once every five seconds. Hayden here again from Alarm System Store. Maximum Ripple Voltage: 30% of nominal (peak to peak), Alarm Current: 130mA max., limited by panel, Standby Current: 50 A max. Copies of this The System Sensor 2WTA-B is a 2-wire smoke and fixed heat sensor with a built-in sounder. (See Figure 6.) It will take approximately 80 seconds for the detector to finish the power-up cycle (see Table 2). 2. hbbd```b``6@$&"%H Each i3 Series detector is supplied with a mounting base that can be mounted: 2.To a 312-inch or 4-inch octagonal box, or, 3.To a 4-inch square box with a plaster ring, or. 30 % peak to peak of applied voltage Models 2WT-B, and 4WT-B also feature a restorable, built-in, fixed temperature, (135F) thermal detector and are also capable of sensing a freeze. The LED indication must not be used in lieu of the tests specified under Testing. detector. item 7 System Sensor 2W-B i3 Series 2-wire, Photoelectric Smoke Detector. To stay in the know on upcoming news and announcements, subscribe. or system undergoing maintenance to prevent any unwanted alarms. Smoke Alarm. You can also remove the detector cover and the sensing chamber for convenient smoke detector cleaning. For the effect of polar distribution (rated candela at each angle), the ANSI/UL 1971 minimum percentages are used for the calculations. FREE delivery Sat, Feb 11. Smoke Entry Test Car & Truck Safety & Security Accessories. system or the conduit, both LEDs will blink for up to 4 minutes before displaying detector status (see Table 2). breach of this or any other Warranty, expressed or implied whatsoever, even if the loss H\@}&&u/tc1.|UH*_7]}8s5CC)^.+Jj__}}}weqxes;,64qh{>?bxN}9_iIg]9.oM:,=nKE%ml)R.g")d6KO)\1WK%yaycN,Y`.K3{daal4{=fOW)=#=#=SoB#. Hold the heat source about 12 inches from the detector to avoid damage 2WTA-B - System Sensor - JMAC System Sensor 2W-B | Page 2 | Electronics Forums This chart contains the current list of detectors and UL Listed compatible control units. However zones 1 and 2 can support 16 on each zone. The 2W-B smoke detector works with most Honeywell alarm control panels including the VISTA-20P and VISTA-21iP as System Sensor is a subsidiary of Honeywell. Fire Alarm Systems | System Sensor L-series indoor horn/strobes System Sensor L-series indoor horn/ strobes www.boschsecurity.com u u Plug-in design with minimal intrusion into the back box u Field-selectable candela settings of 15 or 30 cd at 12 V or 15, 30, 75, 95, 110, 135, and 185 cd at 24 V u Horn rated at 88+ dBA at 16 V Rotary switch for horn tone and two volume settings Out of sensitivity Voltage Drop calculations for System Sensor AV products can be done using the Honeywell Online Tools for Fire (HOTFire) site. 2-Wire i3 Detector Wired in Style D Configuration: B. RA400Z Remote Annunciator to be connected. Wiring Installation Guidelines down firmly until the screen/sensing chamber is fully seated. \kUb5{,P'Zwd**4C8X)z The conductors used to connect smoke detectors to the alarm control panel and accessory devices should be color-coded to reduce the likelihood of wiring errors. The 2W-MOD can The screw terminals in the mounting base will accept 1422 gauge wire. detector which is found to be defective in materials or workmanship under normal use Initial LEDStatus Indication If the detector is within the listed sensitivity limits, the detectors red This includes cleaning, maintenance or screen replacement. CAUTION ANSI/UL 1971 does not provide ratings for each angle based on actual test results.". The System Sensor 2WT-B is a 2-wire smoke and heat detector. endstream endobj 1001 0 obj <>>>/EncryptMetadata false/Filter/Standard/Length 128/O(19[nMM\\.9rvXbp)/P -1036/R 4/StmF/StdCF/StrF/StdCF/U(bH;^Soe9ACM )/V 4>> endobj 1002 0 obj <> endobj 1003 0 obj <>/ExtGState<>/Font<>/ProcSet[/PDF/Text/ImageB]/XObject<>>>/Rotate 0/Type/Page>> endobj 1004 0 obj <>stream To a 4-inch square box with a plaster ring, or Ep. FCC Statement Some parts of this page is temporarily unavailable. VIEW MODELS Beam Smoke Detection 32 to 120F (0 to 49C) These calculations are described in NFPA 72 and are to be provided to the authority having jurisdiction. Condition We offer conventional and intelligent products for smoke detection, heat detection, fire and CO combination detection, and multi-criteria / multi-sensor detection, as well as bases and accessories. I am very happy with the purchase and while I only needed one I bought 2 to have one in reserve. 2. All models incorporate a state-of-the-art optical sensing chamber and an advanced microprocessor. 46 | Microsoft VP Marcus Fontoura on Architecting Azure, the "World's Computer" 0:00 / 0:00. Freeze Trouble (Model 2WT-B and 4WT-B): 4-Wire Smoke Detector with 135F Fixed Heat Sensor, 2-Wire Smoke Detector with Fixed Heat Sensor, System Sensor 2W-B, 2WT-B, 4W-B & 4WT-B - Installation Guide. 3. Each zone provides only enough alarm current (20ma) to power one smoke in alarmed state. covers from any detectors that were left in place during construction. Do NOT Install Detectors in the Following Areas: In or near areas where particles of combustion are normally present such as kitchens; in garages (vehicle exhaust); near furnaces, hot water heaters, or gas space heaters. 12/24 Volts Non-polarized *Assumes the panels alarm verification reset time is 10 seconds or less. If a detector fails any of the above test methods, its wiring should be checked they work perfectly and make me feel much more comfortable while i am away. applicable state and local codes, and any special requirements of the local Figure 3a: Wiring Diagram, 2W-B and 2WT-B. Freeze Trouble Alarm Current: NOTE: T Ensure your FAAST device has the most up-to-date firmware. The microprocessor, allows the detector to automatically adjust its sensitivity back, to the factory setting when it becomes more sensitive due to, contaminants settling in its chamber. such as kitchens; in garages (vehicle exhaust); near furnaces, hot water 6. System Sensor 2W-B Photoelectric i3 Smoke Detector, 2-Wire In Stock Other products from System Sensor System Sensor P4W-P Horn Strobe, White, Wall Mount, Four-Wire System Sensor PC2W Horn Strobe, White, Ceiling Mount, Two-Wire, FIRE Lettering System Sensor B210LP Detector Base, Plug-In : COSMO2W - System Sensor - JMAC Therefore, the only I have since replaced the battery, which has resolved the smoke error. System Sensor 2W-B User Manual This chart contains the current list of detectors and UL Listed compatible control units. This device complies with part 15 of the FCC Rules. Some states do not allow the Electrical Specifications 2-wire 4-wire Wired. The panel has internal knowledge to reset the zone automatically when an alarm is cleared. Amazon.com: System Sensor 2w-b Weight: Wiring Diagrams way to insure proper operation of 2-wire i3 smoke detectors (2W-B, 2WT-B, The EZ Walk loop test verifies the initiating loop wiring and provides Ready to learn more? Storage Temperature Range: Consult the dealer or an experienced radio/TV technician for help. (See the Testing section.) Deciding Whether to Use 2-Wire or 4-Wire Smoke Detectors. DETECTOR Alarm Reset Time: System Sensor web site at www.systemsensor.com. Near fresh air inlets or returns or excessively drafty areas. At a minimum, cleaning should be performed annually. In wet or excessively humid areas, or next to bathrooms with showers. the listed limits, the red LED blinks once every five seconds. maintenance or screen replacement. This notification is not a safety issue, but low battery warnings should be addressed promptly to avoid potential problems with system operations which may arise. All wiring must be installed in compliance with the National Electrical Code, - 2W- B More results Similar Description - 2W-B More results Trending price is based on prices over last 90 days. 130 Alarm Contact Ratings: When mounting the i3 Series, ensure that the head is mounted to the correct base. In order for this feature to work properly, the chamber must never be opened while power is applied to the smoke detector. As long as they operate at 12 Volts DC, they should work. We offer conventional and intelligent products for smoke detection, heat detection, fire and CO combination detection, and multi-criteria / multi-sensor detection, as well as bases and accessories. . mounted: Proper wire gauges should be used. After power-up has completed and the detector is functioning normally within and it should be cleaned as outlined in the Maintenance section. Its simple, step-by-step process makes it easy for users to configure panels and circuits from a variety of devices. 4.Direct mount or to ceiling using drywall fasteners (Figure 2). PDF Device Compatibility Document Once the mounting base is installed, the 2W-B smoke detector attaches to the base by simply inserting the head and turning it clockwise until it locks in place. When the detector is in the alarm mode, the red LED latches on. Fill out our feedback form! 4.8 out of 5 stars based on 20 product ratings, 4.8 out of 5 stars based on 166 product ratings, 4.9 out of 5 stars based on 174 product ratings, 4.8 out of 5 stars based on 175 product ratings, 4.8 out of 5 stars based on 190 product ratings, 5.0 out of 5 stars based on 1 product rating. Notify the proper authorities that the system is in operation. Unfortunately we do not support fire panels like the 32FB. Turn it on by pushing the button of the wired remote. any latin characters (a-z, A-Z) any numbers (0-9) special characters ("-", "_" and ". Loop Verification (models 2W-B and 2WT-B only) PDF System Sensor L-series indoor horn/strobes the 2W-MOD2 installation manual, document D500-4600, for Style D wiring System Sensor BK-2WB Photoelectric i3 Series Smoke Detector, 2-Wire, White Brand: System Sensor ADI #:BK-2WB Model #: 2W-B Name: System Sensor BK-2WB Photoelectric i3 Series Smoke Detector, 2-Wire, White Plug-in detector line, mounting base included Large wire entry port In-line terminals with SEMS screws Product Overview Installation ease. INSTALLATION AND MAINTENANCE INSTRUCTIONS. We're here to help with any issues or questions. Connectivity. No agent, representative, dealer, or employee of the Company has the authority to Power must be removed from the detector To test this please remove AC power and set the panel into alarm mode to see if the battery will support the system and report back. . *Refer to Electrical Specifications for start-up time in conjunction with panel alarm verification. electrical wiring. Multi-voltage conventional relays are used for high-current switching applications, such as fan and damper assembly control, door control, air handling unit controls, and other building system interfaces. However, the i3 Series smoke detector allows for fast and easy inspection. NFPA 72 requirements. it become necessary, the screen/sensing chamber is field replaceable. Table 3: EZ Walk Test Detector Modes It appears that these two models are very similar in their features (neither has a sounder, both operate at 12 or 24 Volts) so this should be a satisfactory replacement. Insert a small screwdriver or allen wrench (0.18 max.) accept any interference received, including interference that may cause undesired operation. into the test unreasonable use, modifications, or alterations occurring after the date of manufacture. System Sensor - Technical Field Bulletin Life Expectancy of System Smoke Detectors - Dated 05/2012, Limitations of Fire Alarm Systems - Dated 5/13 Rev. The i3 Series detectors include a tamper-resistant feature that prevents removal Blink 10 sec Whenever an alarm is detected by the System Sensor 2W-B, the smoke detector will show a solid red LED. models must be used with compatible UL Listed panels only. further simplified by the incorporation of features compatible with drywall In no case shall the Company be liable for any consequential or incidental damages for System Sensors intelligent and conventional modules are designed to help you meet a wide range of application requirements. Ensure proper wiring and power is applied. Vacuum the cover or use canned air to remove any dust or debris. The calculation points are in the horizontal and vertical planes in 5 degree increments per UL 1971. Initial LED Status Indication. switch opening; push and hold. i3 series (4 pages), I3 series. to 35 max. System Sensor's AV notification devices are one of the most versatile, easy to install, and cohesive audible visual (AV) notification appliances in the industry. Red. PDF inSTaLLaTion and mainTenanCe inSTruCTionS Series exclusion or limitation of incidental or consequential damages, so the above limitation best system performance, all wiring should be installed in separate grounded User manual System Sensor 2WTA-B (English - 4 pages) The cable companies often use a special adapter to monitor a VISTA-20P system as explained at https://www.alarmgrid.com/videos/how-to-safely-remove-an-icontrol-from-an-existing-system. B101B / B107B A 120 Remove the detector cover by turning counterclockwise. Amazon.com: System Sensor 2wb Place detector on the base and rotate clockwise. When the detector is in the alarm mode, the red LED latches on. Access all of System Sensor's tools and software offerings. It sounds like a short problem somewhere in the smoke lines to me, but I am not sure. See how you can simplify specification, configuration, and installation of your notification project - saving time and money in the process. Max. and turning it clockwise until it snaps into place. Start-up Time: 3825 Ohio Avenue Test each detector as described in Testing. :9M9yB*]}8s5CC)^.+Jnz>>;?88^]~xxfntMr}->rz_Sxu%fYz,b,v%-]r9Yfl){fy\1W+ye"3#r9c/DfO+"!a4{=ff^,. When I put the system in alarm mode and set it off, the panels still have the same behavior and the sirens (not the keypad alarm) do not sound. Each i3 Series detector is supplied with a mounting base that can be 0.1 on the screen/sensing chamber with the arrow on the housing. System Sensor webinars provide relevant and timely information on products, market trends, and legislation. sensitivity back to the factory setting when it becomes more sensitive due to System Sensor 2W-B i3 Series 2-Wire Photoelectric Smoke Detector KingOfTheP4s 3 yr. ago Best thing to do in this case would be to call the company of your choice, such as EST, and ask a sales representative to give you a list of MRI-safe devices. I am very happy with the purchase and while I only needed one I bought 2 to have one in reserve. All System Sensor i3 Series smoke detectors are designed for easy installation, advanced detection and fast inspection. Peak Standby Current: If the detector still fails, it should be replaced. or exclusion may not apply to you. 0.3 to prevent any unwanted alarms. Two-Wire Compatibility. Direct mount or to ceiling using drywall fasteners (Figure 2). Heat Sensor (Model 2WT-B and 4WT-B): 135F (57.2C) Freeze Trouble (Model 2WT-B and 4WT-B): 41F (5C) Operating Temperature Range: 2W-B and 4W-B: 32 to 120F (0 to 49C) 2WT-B and 4WT-B: 32 to 100F (0 to 37.8C) Operating Humidity Range: 0 to 95% RH non-condensing Storage Temperature Range: -4 to 158F (-20 to 70C) Diameter (including base): How to wire and program System Sensor 2WB series 2 wire - YouTube Our understanding is that EASE Evac voice evacuation design software from AFMG Technologies is intended to help designers and installers save time and money on voice evacuation systems by enabling them to preplan the system to meet new intelligibility code requirements, reduce costly post-installation changes, and limit over-design. View a list of all System Sensor locations worldwide. honeywell smoke detector wired Replace the top half of the screen/sensing chamber by aligning the arrow The Test Switch The microprocessor allows the detector to automatically adjust its In a freeze trouble condition, the red LED will blink once every 10 seconds (refer to Table 1). Have feedback about a particular System Sensor product? Users of this calculator are solely responsible for their own selection and use of products based upon information contained in this calculator and any calculations from this calculator. NOTE: Before performing maintenance on the detector, notify the proper authorities that maintenance is being performed and the system will be temporarily out of service. %PDF-1.6 % Smoke detection for MRI rooms. : r/firealarms - reddit contaminants settling in its chamber. 2W-B and 2WT-B, connect detectors only to compatible alarm control panels There is a red and green LED on the head of the 2W-B smoke detector. Two-wire The 2W-B is a 2-wire, photoelectric i3 smoke detector. General Description The System Sensor 2WTA-B is a 2-wire, photoelectric i3 smoke detector with thermal sensor and built-in sounder. This chart contains the Series detectors are designed to provide open area protec-, tion. The mounting base installation is When performing maintenance on your smoke detector, simply turn the 2W-B head counter clockwise to remove it from the base. When used with an i3 Series compatible control panel or the i3 Series 2WMOD module (refer to installation manual D500-46-00), the 2W-B and 2WT-B monoxide(co)/photoelectric smoke detector (4 pages), Manual will be automatically added to "My Manuals", Installation and maintenance instructions, Smoke Alarm System Sensor 4WT-B Installation And Maintenance Instructions, Smoke Alarm System Sensor 2WT-B Installation And Maintenance Instructions, Smoke Alarm System Sensor 2WTR-B Installation And Maintenance Instructions, Smoke Alarm System Sensor 2100ARFT Installation Instructions Manual, Smoke Alarm System Sensor 2251EIS Installation And Maintenance Instructions Manual, Smoke Alarm System Sensor 22051E-RF Installation And Maintenance Instructions Manual, Smoke Alarm System Sensor 2112 Installation And Maintenance Instructions, Smoke Alarm System Sensor FSB-200 Installation And Maintenance Instructions Manual, Smoke Alarm System Sensor BEAM1224 Installation And Maintenance Instructions Manual, Smoke Alarm System Sensor 2351E Installation And Maintenance Instructions, Smoke Alarm System Sensor DH100ACDCLP Installation And Maintenance Instructions Manual, Smoke Alarm System Sensor 2100AT Installation And Maintenance Instructions, Smoke Alarm System Sensor 6500S Installation And Maintenance Instructions Manual, Smoke Alarm System Sensor i4 Series COSMO-2W Installation And Maintenance Instructions, Smoke Alarm System Sensor Innovair flex D4120A Installation And Maintenance Instructions Manual. NIB!! Wd]_c'F1p% The i3 line redefines installation ease with its plug-in design. Explore System Sensor products including: AV Notification, Beam Smoke detection, CO detection, HVAC Smoke detection, spot smoke detection, relays, & modules. Just fill out the form and click your area of interest. Latching Alarm: Reset by momentary power interruption Therefore, System Sensor recommends System Sensor 2W-B Photoelectric i3 Smoke Detector, 2-Wire, System Sensor P4W-P Horn Strobe, White, Wall Mount, Four-Wire, System Sensor PC2W Horn Strobe, White, Ceiling Mount, Two-Wire, FIRE Lettering, System Sensor B210LP Detector Base, Plug-In, System Sensor 2151 Photoelectronic Low-Profile Plug-In Detector for Special Applications, System Sensor SCWL Strobe, Ceiling Mount, FIRE, White, Clear Lens, System Sensor EOLR-1 End-of-Line Epoxy Encapsulated Relay, SPST, Plug-in detector line, mounting base included, Mounts to octagonal and single-gang back boxes, 4-square back boxes, or direct to ceiling, Drift compensation and smoothing algorithms. the removal of detectors before beginning construction or other dust producing activity. Increase the separation between the equipment and receiver. for System Smoke Detectors, which provides detailed information on detector Installation of the 2W-B, 2WT-B, 4W-B, and 4WT-B detectors is simplified by Hello, I have a vista 20P (came with the house I bought) that has (4) 2 wire smokes wired in. Direct mount or to ceiling using drywall fasteners (Figure 2). The heads and bases are clearly identified as either 2-wire or 4-wire. Alarm, Red LED I've seen three different mri rooms using system sensor 2wb smokes tied to a zone module. 2W-B Datasheet(PDF) - Systemsensor advanced ideas. of a 2W-MOD2 module. 4.3 (21) $6371. Consult the list to locate a control module for your specific fire alarm system. Power-up Solid, After an initial power-up delay, the red and green LEDs will blink synchronously once every ten seconds. he EZ Walk loop test must not be used instead of alarm The LED indication must not, be used in lieu of the tests specified under Testing. For convenience, the 2W-B mounting base can also be directly mounted to the ceiling using drywall fasteners. System Sensor is pleased to provide this Strobe Coverage Calculator, formerly known as Equivalent Facilitation Calculator. 7.7K views 1 year ago DSC Power Series Neo Installation Series Two wire type smoke detectors are arguably the simplest smokes to use with an alarm system, yet we still get installation questions. When the smoke detector is normal the green LED will blink every five seconds. Consult the list to locate a control module for your specific fire alarm system. The i3 Series heads and bases are keyed so that a 2-wire head will only mount to a 2-wire base, and a 4-wire head will only mount to a 4-wire base. Buy the System Sensor 2WT-B here. SWITCH WITH A identifier located on the label on the back of the product. In or near areas where particles of combustion are normally present Thanks for using Alarm Grid as a resource.For the purpose of improving our site, wed like to know if you are one of the following: INSTALLATION AND MAINTENANCE INSTRUCTIONS, Series Explore System Sensor like white papers, announcements, technical bulletins, case studies, and more. Unlike traditional detection systems, Reflected Beam Smoke Detectors were designed for spacious rooms, open areas, and high ceilings; their innovative features make them popular choices for spaces like warehouses, atriums, arenas, and churches. MOD2 module (refer to installation manual D5 00-46-00), the 2W -B and 2WT -B. are capable of gener ating a "maintenance needed" signal. Models 2W-B and 2WT-B are 2-wire photoelectric smoke detectors; models Photoelectric smoke detectors work with an alarm system, and when properly maintained and tested, can last for an indefinite period and do not automatically require replacement after a certain period of time like smoke alarms and CO detectors do. System Sensor webinars provide relevant and timely information on products, market trends, and legislation. FireAlarm.com is always at the forefront of the fire & life safety industry offering the most diverse selection of technologies, offerings, and services - all for you to take advantage of FireAlarm.com is able to offer everything from Fire Alarm System Installation and Security Camera Surveillance, all the way to 24/7/365 Central Station Monitoring and Cellular Signal Transmission . For two-wire models 2W-B and 2WT-B, connect detectors only to compatible alarm control panels as identified by System Sensor's compatibility chart. Models 2W-B and 2WT-B are 2-wire photoelectric smoke detectors; models 4W-B and 4WT-B are 4-wire photoelectric smoke detectors. alarm verification. 2W-B - System Sensor - JMAC 2WT-B and 4WT-B: In wet or excessively humid areas, or next to bathrooms with showers. Read here to learn the difference between smoke detectors and smoke alarms. DSC NEO: System Sensor 2-wire smoke wiring and programming This video showcases the wiring and programming for 2-wire smokes on a DSC NEO security system. The i3 Series 2W-B uses drift compensation technology and smoothing algorithms which prevent the smoke detector from becoming too sensitive as dust accumulates. To measure the detectors sensitivity, the i3 Series Model SENSRDR Infrared Sensitivity Reader tool (see Figure 4) should be used. It will take approximately 80. seconds for the detector to finish the power-up cycle (see Table 2). the temperature is below 41F. Twisted pair may be used to provide additional protection against extraneous electrical interference. fasteners. Explore System Sensor like white papers, announcements, technical bulletins, case studies, and more. Air conditioners, heaters, fans, and fresh air intakes and returns can drive smoke away from the detector. Z@~P]%*?p S_iVN$rtE;[\SmgisL^aOTYVE \xOQc_m1eN"hB~n5#{f-!tEn -:)D#bBc7yo0x&i9Su%t wa+"i At a minimum, cleaning should be performed annually. (135F) thermal detector and are also capable of sensing a freeze condition if Brightness sensor Mode The sensor is activated. In order for this feature to work properly, the chamber must never be opened while power is applied to the smoke Consult NFPA 72, the local Authority Having Jurisdiction (AHJ), and/or applicable codes for specific information regarding the spacing and placement of smoke detectors. prevent a system from responding properly in the event of a fire. NOTICE: This manual shall be left with the owner/user of this equipment. endstream endobj startxref 130 3. 23 mA 24 Volt Systems Our hardwired CO detectors with RealTest use electrochemical sensors to measure carbon monoxide levels and alert residents with a flashing Temp-4 signal alarm. An opening for the recessed test switch is located on the detector housing (See Figure 4). to a 2-wire base, and a 4-wire head will only mount to a 4-wire base. Hold a smoldering punk stick or cotton wick at the side of the detector and Two LEDs on the detector provide a local visual indication of the detectors status: After an initial power-up delay, the red and green LEDs will blink synchronously once every ten seconds. This system was used with Cox before, so no telling what all they did to it. The screw terminals in the mounting base will accept 1422 gauge wire. To calculate performance-based strobe coverage, the inverse square law is used to calculate the illumination at each of the angles in the horizontal and vertical planes per ANSI/UL 1971, Standard for Signaling Devices for the Hearing Impaired, and the effect of polar distribution is included using the minimum percentages in ANSI/UL 1971 or actual test results recorded by the Listing organization. Models 2W-B and 2WT-B also include an output that allows an optional Model RA400Z Remote Annunciator to be connected. System Sensor tools include a variety of software, drawings and calculators to help you effectively plan and prepare for your next fire safety system installation. Smoke Detectors with Sounder and Relay Option To a single gang box, or heaters, or gas space heaters. A05-0395-007 4/09 #2132 SpectrAlert Advance Dimensions Model Description Wall Horn Strobes P2R* 2-Wire Horn Strobe, Standard cd, Red 3. In dusty, dirty, or insect-infested areas. N/A N/A 120 System Sensor 2851B A Photo B101B / B107B A 120 System Sensor 2851BTH A Photo / Therm. This calculator uses data provided by the user to perform the calculations described in NFPA 72, which permits the use of a performance-based alternative in lieu of tables for spacing ceiling mounted audible/visible devices.