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If a duct detector is installed, and the mechanical unit has a capacity of less than 2,000 CFM, it is required by code for the duct detector to be connected to the fire alarm panel?
Alternatively, removing the detectors can be considered in this situation. Looking for relevant code and standard basis. We're under the 2021 IFC, 2021 IBC, and 2019 NFPA 72. Thank you! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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NFPA references are based on current editions. While NFPA 101, Section 30.3.1.1.4 (New Apartments) allows vertical penetrations to be protected with a 1-hour rating when sprinklered, NFPA 101, Section 30.5.2 requires HVAC equipment to comply with NFPA 90A.
According to NFPA 90A, Sections 9.1.3 and 6.8.3, a higher level of protection is required for shafts that penetrate more than four floors (2-hr fire rated and fire dampers). Does the exception provided in NFPA 101 permit reducing the required fire rating to 1-hour for duct shafts, or does NFPA 90A take precedence? I'm curious to hear different perspectives on this. I can understand both sides of the issue but find it challenging to justify allowing a 1-hour fire rating for a vertical exit within a New Apartment while requiring a 2-hour fire rating for the duct shafts. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe If you have an open office area with (2) AHUs, each AHU supply fan provides 1,500 cfm of supply air and return air that is fully ducted and has no common plenum.
Would duct detectors be provided on the supply side of each AHU? Do you combine the "CFM" since both units serve the same area? If not, would you ever cumulatively add multiple units of CFM? This has been an ongoing question as each of our AHJs sees it differently. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe An engineering firm has insisted that a waterflow activation shutdown the HVAC system and cited NFPA 90A: A.6.4.3.
A.6.4.3 Where automatic water sprinklers are provided and zoned to coordinate with the HVAC zones, their water flow switches should initiate devices for the functions described in Chapter 6. Each floor of the building has one HVAC zone and one sprinkler zone (floor control valves). The HVAC system has the appropriate duct detectors and functions. The only instance I have experienced using flow switches for HVAC control is when there is no automatic smoke detection and the flow switch is used to start the smoke control system for that zone. What are your thoughts? Is a waterflow switch required to shutdown an HVAC system on this premise? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a project with a comment from the AHJ stating that the dryer vent cannot terminate to the exterior condominium wall, which is the egress wall for the condominium exit exterior breezeway on that floor.
We're under NFPA 101 (regarding Section 30-3.6.3 for Unprotected Openings). Is a duct penetration considered an unprotected opening? Dry vents cannot have fire/smoke dampers, so can it just be a metal duct? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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