In regards to LSC 18.104.22.168 (2) What would be considered "fully-ducted" penetrations in smoke barriers? Does this require metal ductwork, or would flex-duct also met the requirement. Thanks.
The image below I believe is the best visual I share for a fully ducted system. You have a duct that supplies the air to the room and then a duct that returns air to the HVAC unit.
Are you asking if you need a damper/s? Well you may not if the attic is also sprinklered, in Texas the HVAC system also has to shut down upon activation of the fire alarm.
I dont think any AHJ will be "ok" with using flex duct penetrating a smoke barrier. All the ducts I have ever seen penetrating a smoke barrier have been metal wrapped in fiberglass.
While i understand you may want to save money on certain things when lives could be put in jeopardy you may need to spend a little more.
Also you will need to seal the opening around the penetration with something rated the same as the wall or greater. ( 1 layer/sheet of gypsum board (sheetrock) is 30 minutes most smoke barriers are 2 one on one side of the smoke barrier and one on the other (think of a basic wall))
Do you have pics that maybe you could post to better understand your situation
-LSC Inspector for Texas HHSC/CMS
To me, the intent of this exception is to prohibit open-air transfers at or near the smoke barrier walls and it is not the intent of the exception to permit the damper to be omitted where smoke control system design requires the damper. The exception permits deletion of dampers in ducted penetrations of smoke barriers where compartments adjacent to thebarrier are protected by automatic quick response sprinklers in any smoke compartments used for patient sleeping. Most existing health care facilities constructed prior to 1991 NFPA 101, did not have the requirement of quick response sprinklers in smoke compartments used for patient sleeping. The NFPA 101, Life Safety Code has required the use of quick-response sprinklers since 1991 when the code first mandated sprinklers in all new health care facilities.
Therefore, the fact of when the building plans were approved has a bearing on the application of this section. Chances are the existing smoke barriers were required to be 1-hour fire resistant rated by the Life Safety Code when the building plans were approved. Review of the existing construction plans should reveal this fact.
In accordance with Section 22.214.171.124: "No existing life safety feature shall be removed or reduced where such feature is a requirement for new construction." Which means to me, the requirements for smoke dampers cannot be deleted or the fire resistance rating of the barrier reduced without first consulting with the requirements of the smoke barriers and smoke compartment for new construction.
With all this in mind, the materials of the flexible duct penetrating the fire resistant smoke barrier may not be supported by approved, listed through penetration firestop methods for the required fire resistant rated construction. Simply patching the holes around the flexible ducts will not suffice for the required fire resistant construction.
There is always more to add from the discovery of facts that change the parameters.
Retired LSC inspector WDH-OHLS
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