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Clarification on Use of Passive Natural Smoke Relief Openings in Walls Below ESFR Sprinkler Elevation
I am requesting clarification regarding the compatibility of 'passive natural smoke relief openings located in exterior walls' of buildings protected by ESFR systems. NFPA 13 prohibits the use of automatic roof-mounted heat or smoke vents unless they use high-temperature, standard-response sprinklers, due to possible premature venting interfering with sprinkler operation. Does NFPA 13 or NFPA 92 prohibit or restrict the use of passive, fixed, natural smoke relief openings located in exterior walls (not roofs), which are positioned below the elevation of the ESFR sprinklers and have no operating mechanism (neither automatic nor manual)? These openings are permanently open (fixed, non-operable), not connected to any fire detection or alarm system, intended solely to allow natural smoke movement during fire events, and located entirely below the sprinkler deflector level. Looking to see if these openings are acceptable and whether they otherwise would introduce any related concerns on sprinkler performance or smoke control strategy. Much appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
4 Comments
I am the third-party reviewer for an existing building that is a high-rise but does not have elevator pressurization.
If this were a new building, IBC (2021) Section 3006.3 would apply. But, this is an existing building, and the work qualifies as an Alteration Level 2. The primary engineer says that since the freight elevator is within the work area (although not being touched), per IEBC 801.3, the client will need to install either elevator curtains or a vestibule to keep smoke out per Section 3006.3. I am of the opinion that since they aren't touching the elevator, I think the IEBC 803.1 is a stretch, and the fact that per Exception 5 of the Vertical Openings Section (803.2.1), the elevator isn't even required to be enclosed. (I do think it's a good idea though, and it's not like it's every floor, only their project space would get curtained. This is purely a code required question, though. Does an existing high-rise with Level 2 Alteration trigger smoke management here, even though the elevator is not altered? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am modeling the elevator pressurization system in CONTAM to demonstrate compliance with SBC 201 (IBC-based) requirements.
Normally, we use simplified spreadsheets, but code enforcement now requires performance verification through simulation. In a model where the elevator shaft is adjacent to a protected service lobby, shell and core area, and a loading bay, is it sufficient to demonstrate pressure differentials only along the egress path (shaft → lobby → stair), or should other adjacent but enclosed spaces also be included? What method do you recommend for extracting and presenting results—direct export from simulation (as in ASHRAE Applications, Fig. 21 Ch. 54) or summarized plots similar to Fig. 11.13 in the Handbook of Smoke Control Engineering, 2nd Ed.? Lastly, when modeling the shaft, should it be defined as a flow path with cross-sectional area and perimeter replicated across all floors, except the top floor? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For cycle tracks within a road tunnel, what requirements exist for the bicycle tracks within the tunnels? I have not been able to find any fire or life safety requirements for cycle tracks within road tunnels (exit separation, fire suppression, detection, and emergency communication system requirements) in any codes or standards. Any suggestions on where I could go to or any research papers that I could refer? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  UFC 3-600-01 (with change 6, 2021), Section 4-29.2.1 requires a manually activated smoke exhaust system for Limited-Access Structures three stories or more in height, with 6 air changes per hour throughout the entire building.
NFPA 101 (2024), Section 11.7.3.1.2 and 11.7.3.2 outlines that if there are no unobstructed operable openings, openable from both the exterior and interior of the building, the building is defined as a Limited-Access Structure. Most DoD buildings have security requirements that do not permit operable windows, especially not from the exterior or the interior. Therefore, most DoD structures over two stories in height would require these post-fire smoke purge systems; however, I have not seen them actually being implemented on projects. Is there an alternative code path I am missing, or have you designed and installed these systems in UFC projects? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We are working on a new electric car factory. Under the 2018 IBC, it's classified as an F-2 occupancy. Earlier we had provided ESFR sprinklers in these buildings.
Since there is no specific requirement for smoke removal for an F-2 occupancy, we want to provide standard response or quick response sprinklers instead of ESFR, by classifying parts of the building as Ordinary Hazard Group 2 (OH2) in NFPA 13. Is this reasonable for all areas? Production areas? Would an OH2 classified space require smoke removal? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe [Moderator's note: since the first lithium battery question a few weeks ago, we've been flooded with more questions on the topic. We'll do our best to not overburden everyone here but still keep with the topics people are asking. As always, we're thankful for you all!]
Could anybody point out some publications that deal specifically with the ventilation of lithium-ion batteries during off-gassing and how the ventilation should be controlled? I am familiar with FM Global Loss Prevention Datasheet, and NFPA 855, and I went through some publications such as FIA, however from those I only get that there should be sufficient ventilation. I am more interested in the off-gas detection part of the design. The ventilation should be turned on and ESS turned off at the first sign of explosive gasses, but what gasses should those be? H2, CO, C2H4, CH4, or all mentioned in a combination? Not sure how to proceed in this. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe IBC Section 909.12 and 909.3 requires weekly smoke control tests for smoke control systems.
Can this test suffice for positive confirmation of power to the smoke control system? Or, is a monitor module required on the power source to the smoke control fan to confirm power to the system? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For a smoke control stair pressurization system designed in accordance with IBC 909 and IMC 513, does the code require a duct smoke detector on the supply fan?
Does the installation of a smoke damper at the stairway boundary factor into this requirement? (i.e. IBC 717.3.3.2 requires a detector within 5 feet of a smoke damper). Normally this motorized smoke damper is closed and then automatically opens upon activation of a specific fire alarm signal. NFPA 92 6.4.6.2 does require a duct detector on the stair pressurization supply fan; however, I'm unaware of a similar requirement in IBC/IMC. NFPA's intent is to detect smoke on the air supply and shut down the unit before smoke compromises the stairway. For elevator hoistways that require smoke control, IBC 909.21.4.2 states to provide a detector. I would have expected a general statement in IBC 909.12 with the same intention as NFPA 92; however, I do not see a similar requirement in the IBC/IMC for stairways. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe The International Fire Code (IFC) Section 6004 for highly toxic and toxic gases states the following for exhausted enclosures:
6004.1.3(1) The average ventilation velocity at the face of the enclosure shall not be less than 200 feet per minute with not less than 150 feet per minute. However, in the same section for gas cabinets (Section 6004.1.2(1)), the words "at any point of the access port or window" are added after "150 feet per minute." Doe anyone know if this was an oversight by the authors of this section? Did they miss a few words in the requirement for exhausted enclosures? I don't understand why the 150 feet per minute would be for gas cabinets but not exhausted enclosures (albeit without referencing where the 150 feet per minute measurement is to be taken). This issue is coming up at my work as we have several exhausted enclosures and gas cabinets and some of the exhausted enclosures have ports/windows which are sealed shut. Thanks in advance! Sent in anonymously for discussion. Discuss This | Submit Your Question | Subscribe An existing F1 occupancy with no high-piled storage is getting an addition, resulting in the total square footage for the entire F-1 area (all open) being over 50,000 ft sq, thus requiring smoke and heat vents per the 2012 IBC and IFC.
The question was asked if smoke and heat vents can just be added to the new addition and install a draft curtain to separate the existing from new, so smoke and heat vents will not be required in the existing space. My question is, would a draft curtain be sufficient for creating a divided area in this regard? There is no true definition of a divided area in either the building or fire codes. I wouldn’t think it would necessarily need to have a fire barrier or partition. I would assume a properly sized trap curtain would be sufficient? Does anybody have any experience with this unique type of issue, or have any comments or suggestions? Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe We have an auditorium with a stage area. The stage area is fully sprinklered and provided with four natural smoke vents at the roof.
Below the smoke vents at a depth of almost 10-feet (3 meters) there is structural steel frame (provided for structural stability) arranged with narrow gap of only about 1-inch (30 mm) and obstructing all the smoke vents. We understand this steel frames will deflect the smoke plume and affect the performance of smoke vents. Is there a standard/code reference regarding how to include this obstruction in the calculations and to prove to AHJ that the smoke vents would still be sufficient? Thanks in advance. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe This building is an H-1 occupancy. There is an area of refuge on the 4th floor. The shelter-in-place Class 3 area of refuge is protected from interior and exterior hazards. There are vertical openings through all 4 floors. The UFC is governing.
Based on this, do the stairwells need to be intertied directly to the shelter-in-place area of refuge for an exit enclosure that is a direct accessible means of egress (we are providing accessibility provisions)? Does the shelter-in-place area need to be a smoke enclosure as well as the interconnected stairwell system? Based on this will both the stairwell and the shelter-in-place need to be pressurized to meet design intent? Both exterior and interior air is hazardous and a scrubber would be needed to inject air for stairwell pressurization. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Being told I need two fire dampers to serve a single fire wall. The fire wall is made of a "double wall", essentially two masonry walls next to each other with a very small (less than 2-inch) air gap in-between. The engineer on the project is stating that this "double wall" requires a fire damper in each.
I've never come across this as a requirement before. Do I need two fire dampers? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe We have a project where a control module is connected to the mechanical controls that is programmed to the variable frequency drive for a fan on a large unit. When a duct detector senses smoke, the control module (which is normally-open circuit) will close the circuit, sending a signal to the mechanical controls which shuts down the unit.
On this project we had a bad set of control modules that didn't work. We discovered this in testing with the local jurisdiction, and swapped out the modules and the system now works correctly. Both the jurisdiction and I wondered whether this normally-open arrangement is acceptable. If a control module were to fail, the duct detector would not be able to close the circuit on the module and the fan would remain running. In this scenario, there would be no supervision or way to know that the control module failed other than someone standing at the fan or finding the issue during testing. My inclination is that in the future these modules could be normally-closed and open upon duct detection. That way if the module fails and opens on its own, the unit will shutdown in a "failure" mode. Is it code required that this arrangement be fail-safe? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Have a project that requires the sprinkler system to be zoned by the areas with active smoke control. Each floor of the highrise is approximately 12,000 sqft is to be divided into two zones. I intend to have multiple floor control risers (valve, check valve, flow switch, pressure gauge, inspector's test & drain) for each smoke control zone. Is there any less costly way of accomplishing this?
It has been suggested that multiple flow switches can be placed on the same system with different retard settings so that the fire alarm system can identify where the water is flowing, but I don't have experience with this option. Posted anonymously by a member for discussion. Discuss this | Subscribe. |
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