Has anyone come across a dual riser (dual-feed) sprinkler system in an office tower, with only a single inspector's test?

What is the proper method of testing each flow switch?

In most cases, only the flow switch nearest the inspector's test will operate in a timely manner. Some inspectors will isolate and test, others believe the system should be tested under normal conditions with both control valves open.

Is the deficiency the lack of a second test connection, or that the flow switch doesn't operate within 90 seconds (or even 5 minutes)? Alternatively, is there no deficiency at all?

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We are designing a clean agent system for electrical rooms located within a high-rise building. We are proposing having dedicated clean agent releasing control panels for the electrical rooms, and a separate building Fire Alarm Control Panel.

Is it mandatory to connect fire/smoke dampers (and other shutdown devices) in the electrical room with the clean agent releasing panel, or can these be connected to the building fire alarm system?

Thanks in advance.

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We are working on a mass notification system design. We have always called for any speaker/strobes in close proximity to the microphone to be shutoff during live announcements to prevent feedback.

Is there an actual recommended distance away that all speakers located within this distance should be shutoff? 

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Does anyone have experience installing a heat detector in a cold environment (~ -40 degrees C or F)?

I'm thinking a rate-of-rise detector would probably be the right type based on what I've read but having problems finding a cut-sheet that supports that operating environment. Normally this type of space would get a dry sprinkler but some things have led to trying to think "outside the box" for this project. Thanks in advance.

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Under NFPA 72 fire alarm manual pull stations are required on both sides of grouped openings over 40-feet in width and within 5-feet of each side of the grouped openings.

What about grouped loading bays or loading docks? Are manual pull stations required on each side of grouped overhead doors?

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Any good software resources out there for predicting fire alarm signal audibility across walls and doors based on their attenuation values and ambient sound pressure?

​Editors Note: Another fire alarm question today, love it. Keep 'em coming! You can post any fire protection-related question using the "Submit Your Question" link below at any time.

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As a consultant, what level of detail do you go into for the line voltage (120v) fire alarm plans and wiring?

The line voltage is affected by loads / fuse sizes and affects the disconnect switch size. I'm wondering about the level of detail that an engineer should be showing versus leaving the sizing to the fire alarm and electrical contractors based on their specific system layout requirements.

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We have an auditorium project with a walkway that is constructed beside the seating area at the first and second levels. The second level has been provided with beam-type smoke detectors. 

There is a suspended ceiling below the walkway which is approximately 6-feet (2 m) from the wall. Do we need smoke detectors below this suspended ceiling?

The design currently has smoke detectors only inside ceiling void spaces below the walkway - is this in compliance with NFPA 72?

The fire alarm contractor is arguing that if a fire originates at the floor level below this walkway, it will be easily detected by the beam detector at the second level due to the smoke buoyancy. 
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Which of the following would not require a re alarm system?
a. A new second-floor tenant insurance sales office of 60 people
b. An existing four-story fraternity house of 70 people
c. A single-story 80,000 sqft high-hazard warehouse of 90 people
 d. A new single-story 35,000 sqft Class A department store

Solution | Posted 10/14/20

A forensic investigator is trying to determine approximate timing of events after a re within a hospital basement. A quick response sprinkler (RTI of 50 m^1/2s^1/2), Ordinary Temperature (65 deg C) was within a room (2.2 m high ceiling) that has an initial temperature of 70 deg F and was exposed to a ceiling plume at 190 deg F traveling at 2.3 m/s. Approximately how long should it have taken the sprinkler to activate? 
a. 1 seconds 
b. 15 seconds 
c. 23 seconds 
d. 35 seconds

Solution | Posted 10/13/20

Have a four-story project that is under 2015 IBC and NFPA 101. NFPA 101, for fully-sprinklered buildings with accessible floor levels (floors 2-4 included) - designates the entire floor level as accessible and an area of refuge. Reference NFPA 101 7.2.12 and NFPA 72 24.10.

Along with that designation includes a requirement for a two-way communication system generally next to the elevator bank for the building. There's not much detail out of NFPA 101, and I'm finding very few people are familiar with these systems.

Who typically specifies and provides details/locations on these systems?

It is not tied into the fire alarm system - yet is related to life safety - so we're getting some feedback that these systems should be shown on fire alarm plans. However, the fire alarm subcontractors have nothing to do with these systems. Low voltage / specialty consultants are stating that the systems are code mandated and aren't looking to coordinate these locations with fire marshals and plan review.

It's not a cost item and no one is pointing fingers - but I am trying to understand going forward where these systems are typically shown on plans and who should be specifying them? 

Thanks in advance.

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Are initiation devices (smoke detectors, manual pull stations, duct detectors) required to have individual labels on them showing the device address?

The project in question is military and is also subject to UFC requirements.

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The activation time (in seconds) of a standard response (RTI of 85 m^1/2s^1/2), Ordinary Temperature (65 deg C) heat detector within a room that has an initial temperature of 22 deg C and exposed to a ceiling plume at 78 deg C traveling at 2.3 m/s is most nearly what time?
a. 10 s
b. 36 s
c. 54 s
d. 82 s

Solution | Posted 09/17/20

NFPA 72 requires a battery test be run including removal of the main power supply, waiting the full-length standby time, then activating the fire alarm system for the full alarm time. After the alarm time, the battery voltage is required to be tested.

What is the pass/fail mark for the battery voltage?

In theory, if the battery output still has 20.4 V, then the last appliance on a NAC circuit would still get a minimum of 16 V and everything still functions correctly. I just can't seem to find a code reference whether 20.4 V is the correct voltage to use (where a voltage reading below 20.4 V fails the battery). 

Thanks in advance.

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I am a municipal fire inspector. We have a new high school, fully sprinklered, that has residential stoves in a classroom. These are protected with UL300A hoods.

Are these hoods required to be connected to the fire alarm?

Common sense would indicate that if there was a fire hot enough to release the UL300A system, that the building occupants could be in danger and the fire alarms should activate, however, I cannot find a code reference for this. The architect is saying the stoves are residential so only residential requirements apply.

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Solution | Posted 08/21/20

​Determine the response time index (in ft^1/2 s^1/2) for a 160-degree F heat detector with a listed spacing
of 30 feet.
a. 44
b. 80
c. 169
d. 180

Solution | Posted 07/30/20

Should return air duct smoke detectors associated with a fan system close only the associated damper and shutdown the fan or close all dampers on the system (including supply return spill and outside air)?

How should outside air and spill air fire smoke dampers be controlled? Should these to be controlled by fire alarm?

Thanks in advance.

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I'm working within a campus environment, and costs are something that always arise at some point during ITM conversations.

Does anyone have a great resource or tool to help to estimate a ballpark cost of ITM over a life of the building?

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I’m confused by the field of view intent of NFPA 72 for synchronization.

Do two adjacent rooms with a door between them each with strobe coverage require synchronization?

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Question for AHJs and inspectors:

Do you occasionally see fire alarm strobes mounted on the ceiling that appear to be for a wall-mounted orientation (e.g. they are rectangular and have the word "FIRE" on the side)?

I know some of these are actually for ceiling mounted applications but I've run across some that are wall-mounted only. I think the Wheelock brand might be an example? Stuff like this is hard to tell in the field for an existing building (with no documented cut sheets for what was submitted).

Anyone have tips or tricks for this?

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What constitutes a "drop" on a fire alarm Class A circuit?

NFPA 72 12.3.8.1 (2016 Edition): 
"The outgoing and return circuit conductors shall be permitted in the same cable assembly, enclosure, or raceway only under the following conditions:
(1) For a distance not to exceed 10 feet where the outgoing and return conductors enter or exit the initiating device, notification appliance, or control unit enclosures.
(2) Single drops installed in the raceway to individual devices or appliances.
(3) In a single room not exceeding 1000 sq ft in area, a drop installed in the raceway to multiple devices or appliances that does not include any emergency control function devices."

For this project in question an appliance is located approximately 12 feet away from a device. The circuit runs from the device, out 12 feet horizontally, down a wall a few feet, then back up and back to the first device. 

In my opinion, the outgoing and return circuit exceeds 10 feet so it would not qualify as Class A wiring. However, the contractor is calling this a "single drop" to an individual appliance, so he feels it qualifies as exception (2) above.

Is this considered a single drop if it's only serving an individual appliance?

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Our common CRAC Units (Cooling, Refrigeration and A/C) for data centers only cool the air directly from the data center and back into the data center.

Do these need to be shutdown with the use of a total-flooding clean agent system? 

If the CRAC unit is only exchanging air within the same space then I'm not sure what harm it would do if it's running during or after clean agent discharge. I'm curious if I'm off the mark here, thanks!

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When an elevator does not have an elevator machine room, where should the fire alarm relays for the elevator be located?

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