Q: We are installing fire extinguisher cabinets in a rated smoke partition wall. Do we need special seals or other measures to keep in compliance with the smoke rating?
- Christa J., Architect, Austin, Texas
Dear Christa,
Great question and there is a simple answer but we should probably qualify that simple answer.
First, we should clear up that the International Building Code is referenced based and relies on standards from a variety of other standards and sources. This broadening of the building code has made smoke protection or mitigation of smoke more of an issue and it will likely continue to be more important for designers to continue education as this part of the code continues to evolve.
It may seem odd as to why we even need a smoke partition and when would a smoke partition be used in a practical application? According to the National Fire Protection Agency statistics released a few years ago, demonstrated smoke inhalation was responsible for 73 percent of structure fire deaths. And a large share of these victims weren’t found in the room where the fire began, meaning that lethal concentrations of smoke had migrated from the point of origin.
“Smoke is a killer, and it usually arrives before the fire,” says Steve Younis, senior fire protection engineer at NFPA. “If you can capture smoke before it reaches potential victims who are remote from the fire and protect their escape paths out of the building, you can greatly reduce the hazards of smoke, and let the suppression system and fire department take care of the fire.”
To your question: First we need to be certain it is a smoke partition we are discussing and not a smoke barrier. Smoke barrier, as defined by the International Code in Section 709 requires the same installation and ratings for one-hour fire rated construction and is intended for a division of a building.
To meet this requirement for cabinets that are recessed or partially recessed into a partition, the wall and ceiling contractors would line the cabinet area with Type X gypsum board and tape the joints for an effective seal and meet the required fire protection. This method is still acceptable and allowed by almost all building code authorities. However, this protection is concealed after completion of the building and on subsequent site visits, the Fire Marshall would prefer to see the extinguisher cabinet itself rated with a label from an accredited fire testing agency, such as UL (Underwriters Laboratory) or Intertek Testing Services. The designer has the option in fire rated wall construction and smoke barriers to “line the opening” with gypsum wallboard or specify a tested fire rated cabinet.
Standard metal style cabinets installed with a “gypsum wallboard lining” in a fire-rated partitions.
But your question was on the less restrictive smoke partitions applications. Smoke partitions are in section 710 and are less restrictive than smoke barriers. The code intends for smoke partitions to resist the passage of only smoke; this would include any and all penetrations in the smoke partition. Thus, the fire extinguisher cabinet, and any penetration must also be capable to resist only the passage of smoke.
Smoke partitions, as noted, are not necessarily required to be fire-rated and are only required to be constructed to resist the passage of smoke. While each interpretation may vary slightly, this should be taken to mean a fire extinguisher cabinet need not be fire rated and the opening is not required to be lined with gypsum wallboard.
However, the opening “is” required to be sealed to resist the passage of smoke. The material is not required to be a fire-stopping sealant, product or intumescent material. As stated in the Gypsum Association Fire Design Manual, which is referenced in the code, “Fire-resistive gypsum systems with perimeters and penetrations sealed to achieve listed STC (Sound Transmission Control), also function to resist the passage of smoke.” This would translate to standard joint compound for connections to gypsum wallboard and any flexible acoustical type sealant around the openings or dynamic joints. W&C
If you have a question for Cracking the Code, send it via e-mail to John Wyatt, editor of Walls & Ceilings magazine, at wyattj@bnpmedia. Please include “Cracking the Code” in the subject line.
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