MeyerFire
  • Blog
  • Forum
  • PE Exam
    • PE Forum & Errata
    • PE Problems
    • PE Store
    • PE Tools
    • PE Prep Series
  • TOOLS
    • TOOLKIT (FREE TRIAL)
    • *TOOLKIT (PURCHASE)
    • SUBMIT AN IDEA
    • BACKFLOW DATABASE*
    • CLEAN AGENT ESTIMATOR
    • CLOUD CEILING CALCULATOR
    • DOMESTIC DEMAND
    • FIRE PUMP ANALYZER
    • FIRE PUMP DATABASE*
    • FIRE FLOW CALCULATOR*
    • FRICTION LOSS CALCULATOR
    • HANGER SPACER
    • IBC TRANSLATOR*
    • K-FACTOR SELECTOR
    • NFPA 13 EDITION TRANSLATOR ('19 ONLY)
    • NFPA 13 EDITION TRANSLATOR ('99-'19)*
    • LIQUIDS ANALYZER*
    • OBSTRUCTION CALCULATOR
    • OBSTRUCTIONS AGAINST WALL*
    • PLUMBING FIXTURE COUNTS
    • REMOTE AREA ANALYZER
    • QUICK RESPONSE AREA REDUCTION
    • SPRINKLER DATABASE*
    • SPRINKLER FLOW*
    • TEST & DRAIN CALCULATOR
    • THRUST BLOCK CALCULATOR
    • TRAPEZE CALCULATOR
    • UNIT CONVERTER
    • VOLUME & COMPRESSOR CALCULATOR
    • WATER SUPPLY (US)
    • WATER SUPPLY (METRIC)
  • TOOLKIT
  • LOGIN
  • STORE
  • About
Picture
ALL THINGS FIRE PROTECTION | SUBSCRIBE NOW

Duct Detectors Shut Only Associated Damper or All Dampers? How Should they be Controlled?

7/8/2020

7 Comments

 
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.

​​Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe


7 Comments
Jonathan Sullivan
7/8/2020 10:22:54 am

It depends. I think we need more information to help you. Is this equipment part of an engineered smoke control system, what type of fire alarm system do you have, is there a fire command center with damper control, etc.

You also want to review IMC assuming that’s your local code, the duct systems chapter addresses the basics of where, when, and how.

Reply
Manny Rios
7/8/2020 10:25:35 am

In our jurisdiction and in compliance with applicable code requirements, (Mechanical and NFPA72) the hvac systems are designed with all devices connected to the fire alarm.

During an activation of the fire alarm system by the use of a pull station or a fire/smoke detector, duct detector, all fire/smoke dampers close as designed.

Reply
Scott McCormick
7/8/2020 10:50:09 am

Duct detectors are the MOST misused fire alarm device. I've seen more duct detectors installed that weren't required in the first place. People don't understand what the purpose of the detector. Perfect example, Lowes, Home Depot, Walmart, BJ's etc. large RTU with minimal duct work. Bam duct detector. Why? Where is the smoke going? I've had more Engineers and contractors say, "it's more than 2000 CFM." my answer is, So! Again I ask, Where is the smoke going to go? I have done a lot of research, and I understand the purpose. Read the documents about the MGM fire, La Vegas 11/21/1980 most of the 85 dead, died of smoke inhalation. When connected to a fire alarm system, these should be supervisory only.

Reply
Bruce Verhei
7/10/2020 08:01:57 pm

The essentially no duct HVAC units at ceiling-roof level have been at top of Tomes Van Rickley & Assoc., then TVA, then Telgian’s Pre-app meeting building department checklist for twenty-five years. I believe by now they’ve managed to have the requirement explicitly not required any more in the IMC.

For the record, I would eliminate the duct detector requirement in many single sprinklered buildings that only shut down the ventilation system. I’m not convinced it improves life safety. If you want to shut down the HVAC system the sprinkler heads and water flow switch are adequate.

Best.

Bruce Verhei

Reply
Chris D
7/8/2020 11:46:21 am

Duct detectors typically shut down the entire HVAC system they are associated to but not all systems in the building.

In healthcare, I have a fire alarm relay close the associated damper immediately signal via an AHU interface to BAS or AHU and include a sequence to close all dampers upon shutdown (avoids air pressure ductwork damage and problems with pressurization).

For commercial, an HVAC unit shutdown via fire alarm interface to the associated AHU and closing all dampers as part of that interface can be the least messy, I use a hardware interface to the AHU rather an a BAS integration that includes software (unless smoke control listed equipment / programming is used.) In many cases the dampers can be shutdown by shutting power to a circuit that powers all dampers on the system other than individual relays, these should be fail-secure to avoid having to monitor power, a delay may be programmed via the fire alarm panel that allows a signal to the AHU to shutdown and then kills powers to the damper circuit. Individual relays per damper are possible, but expensive with little benefit.

Outside air typically wouldn't have a fire smoke damper, when I was a contractor I would assume anywhere a designer of record included a fire/smoke damper both detection and control is required; it may not hurt to RFI and ask them to confirm as I can't think of a code requirement to shutdown outside air.

Reply
Glenn Berger
7/8/2020 12:21:13 pm

There is no one right answer. It all depends on the geometry of the facility being protected and the arrangement of the HVAC System.

Reply
MHK
7/21/2020 02:46:09 am

I have looked at 6.4.3.1 of NFPA 90A (2018 ed.) and found that duct smoke detectors are only to stop their respective fan(s). Am I geeting anything wrong here?

Reply



Leave a Reply.

    Jump to: Daily Posts
    Jump to: PE Problems
    Picture
    Why Sponsor?

    Free Signup

    Subscribe and learn something new each day:
    I'm Interested In:

    Community

    Thank You to Our Top
    ​February '21 Contributors!
    1. Dan W.
    2. Franck
    3. Jesse
    4. CJ B.
    ​5. Brian G.
    6. Mike
    7. Matt
    8. Casey M.
    9. Jay R.
    10. Glenn B.

    Your Post

    SUBMIT A QUESTION

    The Toolkit

    Sprinkler Designer or Engineer?
    ​
    ​Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more:
    Picture
    FREE 30-DAY TRIAL
    GET THE TOOLKIT

    Filters

    All
    ABA
    ADA
    ASCE 7
    ASME A17.1
    Daily Discussion
    Design Documents
    Explosion Protection & Prevention
    Fire Detection And Alarm Systems
    Fire Dynamics
    Flammable & Combustible LIquids
    FM Global
    Human Behavior
    IBC
    IFC
    Information Sources For Analysis
    IRC
    Means Of Egress
    NFPA 1
    NFPA 10
    NFPA 101
    NFPA 11
    NFPA 110
    NFPA 12
    NFPA 13
    NFPA 13D
    NFPA 13R
    NFPA 14
    NFPA 15
    NFPA 17A
    NFPA 20
    NFPA 2001
    NFPA 214
    NFPA 22
    NFPA 24
    NFPA 25
    NFPA 291
    NFPA 30
    NFPA 33
    NFPA 400
    NFPA 415
    NFPA 497
    NFPA 5000
    NFPA 502
    NFPA 54
    NFPA 55
    NFPA 654
    NFPA 68
    NFPA 70
    NFPA 72
    NFPA 92
    NICET
    Passive Building Systems
    PE Prep Guide
    PE Prep Series
    PE Sample Problems
    Poll
    Smoke Management Systems
    Special Hazard Systems
    Types Of Analysis
    UFC 3 600 01
    UFC 3-600-01
    Updates
    Water Based Fire Suppression
    Weekly Exams


    Archives

    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    November 2016
    October 2016
    July 2016
    June 2016


    Daily
    Daily discussions are open-ended fire protection, fire alarm, and life safety questions submitted anonymously for the benefit of sharing expertise and learning from other perspectives. Anyone can submit a question here:
    SUBMIT A QUESTION

    Exam Prep

    Picture
    2020 PE Prep Guide​
    ​(Available Now!)
    Picture
    PE Prep Series
    ​(Available Now!)
    2020 PE Prep Series
    Current Leaderboard
    ​(Click to enlarge)
    Fire Protection PE Exam Prep

    PE Problems
    ​Visit July-October for daily Fire Protection PE Exam sample questions.

    Solutions are posted the day after posting.

    Comment with your solutions, questions or clarifications.

    Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves.

    RSS Feed

Picture
Home - About - Blog - Contact - Exam Prep - Store

​Copyright © 2021 MeyerFire, LLC

The views, opinions, and information found on this site represent solely the author shown and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a commission for orders placed elsewhere.
  • Blog
  • Forum
  • PE Exam
    • PE Forum & Errata
    • PE Problems
    • PE Store
    • PE Tools
    • PE Prep Series
  • TOOLS
    • TOOLKIT (FREE TRIAL)
    • *TOOLKIT (PURCHASE)
    • SUBMIT AN IDEA
    • BACKFLOW DATABASE*
    • CLEAN AGENT ESTIMATOR
    • CLOUD CEILING CALCULATOR
    • DOMESTIC DEMAND
    • FIRE PUMP ANALYZER
    • FIRE PUMP DATABASE*
    • FIRE FLOW CALCULATOR*
    • FRICTION LOSS CALCULATOR
    • HANGER SPACER
    • IBC TRANSLATOR*
    • K-FACTOR SELECTOR
    • NFPA 13 EDITION TRANSLATOR ('19 ONLY)
    • NFPA 13 EDITION TRANSLATOR ('99-'19)*
    • LIQUIDS ANALYZER*
    • OBSTRUCTION CALCULATOR
    • OBSTRUCTIONS AGAINST WALL*
    • PLUMBING FIXTURE COUNTS
    • REMOTE AREA ANALYZER
    • QUICK RESPONSE AREA REDUCTION
    • SPRINKLER DATABASE*
    • SPRINKLER FLOW*
    • TEST & DRAIN CALCULATOR
    • THRUST BLOCK CALCULATOR
    • TRAPEZE CALCULATOR
    • UNIT CONVERTER
    • VOLUME & COMPRESSOR CALCULATOR
    • WATER SUPPLY (US)
    • WATER SUPPLY (METRIC)
  • TOOLKIT
  • LOGIN
  • STORE
  • About