Feb 23 2015

Fully Ducted HVAC System

Category: HVAC,Questions and Answers,Smoke CompartmentBKeyes @ 6:00 am
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Q: I have never been able to understand what a fully ducted heating system is and when a damper is not required. Can you explain this matter to me?

A: ‘Fully ducted’ HVAC systems are those in which the air in the HVAC system travels from the air handler to the room diffuser in ducts. The alternative is open return-air plenum ceilings or open supply-air plenum ceilings. Those types involve the open space above the ceiling for the movement of air, and there is no HVAC duct in that area. The return-air plenum ceilings are much more common than supply-air plenum ceilings, and would have an opening at the smoke compartment barrier (above the ceiling) to allow the movement of ventilation air without being inside ducts. What the Life Safety Code is saying is if you have ‘fully ducted’ HVAC system from the air handler all the way to the room diffuser on both the supply and return sides, and it penetrates a smoke compartment barrier, then the LSC does not require that you have a smoke damper in this barrier if the smoke compartments on both sides of the barrier are protected with sprinklers. While this is a huge benefit for facility managers, if you are required to comply with the International Building Code (IBC), they do not allow this exception, and you would have to have smoke dampers at the barrier.


Apr 07 2014

Smoke Compartments in ASC

Q: We are a freestanding ambulatory surgical center (ASC) and we only perform gastrointestinal (GI) procedures, not surgery. We lease a suite on the ground level in a 3 story building with multiple tenants. During a recent state inspection, I was asked where our smoke compartments are located. I know that we have a 2-hour fire barrier between us and the other suites on our level, but I am not aware that we have any designated smoke compartments. Do we need smoke compartments?

A: You did not mention how many patients are incapable of self-preservation at any one time, so I will assume it is at least 4 or more patients, since that is the threshold to decide if the ASC is required to comply with ambulatory health care occupancy requirements, or business occupancy requirements. Ambulatory health care occupancy smoke compartment requirements are found in section 21.3.7.2, which requires your ASC to be sub-divided into not less than two smoke compartments. However, there are some exceptions to this requirement:

  1. ASC facilities that are less than 5,000 square feet and are protected by an approved smoke detection system do not need to be sub-divided.
  2. ASC facilities that are less than 10,000 square feet and are protected throughout by an approved automatic sprinkler system do not need to be sub-divided.
  3. An area in an adjoining occupancy may be permitted to serve as a smoke compartment for the ASC facility, provided all of the following criteria is met:
  • The separating barrier must be at least 1-hour fire rated, and have doors that are self-closing.
  • The ASC facility is less than 22,500 square feet.
  • Access from the ASC facility to the other occupancy is unrestricted.

So, to answer your question, based on the size of your ASC and whether it has smoke detection or sprinkler protection, it may not require a smoke compartment barrier. If a smoke compartment barrier is required, you might be able to utilize the 2-hour fire rated barrier between you and your neighbors, if you are less than 22,500 square feet and if there is unrestrictive access to the other occupancy.


Mar 14 2013

Smoke Compartment Barriers

Category: Questions and Answers,Smoke CompartmentBKeyes @ 5:00 am
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Q: Are smoke compartment barriers considered to be fire rated barriers? The architect that we have doing our drawings wants to call the smoke compartment barrier walls “1-hour smoke/fire barrier”, which to me means it is both, and must meet the most restrictive requirements of both.

A: To be sure, a smoke compartment barrier is not a fire rated barrier, even though the smoke compartment barrier wall may be 1-hour fire rated. While section 18.3.7.3 of the 2000 edition of the Life Safety Code requires the smoke compartment barrier (for new construction) to be 1-hour fire resistance rated, section 18.3.7.5 says doors in smoke compartment barriers “shall be substantial doors, such as 1¾ inch thick, solid-bonded wood core doors, or shall be of construction that resists fire for not less than 20 minutes.” Notice that it does not say the doors have to be 20 minute fire rated, just “of construction that resists fire for not less than 20 minutes.” By definition, a solid-bonded wood core door qualifies as a door that resists fire for not less than 20 minutes. Does a 20-minute fire rated door qualify to be used in a smoke compartment barrier? Yes it does, but if you install a fire rated door, then you must install all the fire rated hardware that goes with it, such as a rated frame, closer, and positive latching hardware. In this scenario, the arrangement would not come close to meeting the requirements for a 1-hour fire rated barrier, since a ¾ hour fire rated door would be required. Now, more to your point, a smoke barrier may also serve as a fire rated barrier as long as the requirements for both barriers are met. This would mean a combination smoke/fire barrier would have to be fire rated (can be either 1-hour or 2-hour, depending on the need for the fire barrier), and the doors in the barrier would have to be appropriately fire rated (3/4 hour rated for a 1-hour barrier, and 1½ hour rated for a 2-hour barrier), with a rated frame, closer and positive latching hardware. Your architect may have a need for a combination smoke compartment barrier and a fire rated barrier, and it is perfectly fine to combine them together into one as long as you meet the requirements for both barriers. However, if the barrier in question is truly a smoke compartment barrier, and not a fire rated barrier, then there is no reason to label it a 1-hour smoke/fire barrier, and there is significant danger in doing so. A surveyor may read the drawing and see the word “fire barrier” and hold your barrier accountable for meeting the requirements of a fire rated barrier.


Jan 01 2011

Downgrading Smoke Compartment Barriers

Category: Questions and Answers,Smoke CompartmentBKeyes @ 6:18 pm
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Q: In 1970, our smoke compartment barriers were originally constructed to 1-hour fire ratings, but I see that the Life Safety Code allows existing smoke compartment barriers to be only ½ hour fire rated. Since they are now considered existing, are we allowed to downgrad our smoke compartment barriers to ½ hour even though they were originally built to 1 hour? This would be an advantage for us as some of these walls are no longer 1-hour fire rated.

A: No, you are not allowed to downgrade existing smoke compartment barriers to ½ hour if they were originally constructed to 1-hour fire resistive rating. Section 4.6.7 of the 2000 edition of the Life Safety Code says any alteration to the building shall meet the requirements for new construction. As you indicated, the smoke compartment walls have been modified (or altered) as they are no longer 1-hour fire rated. Section 18.3.7.3 requires new smoke compartment barriers to be 1-hour fire resistive rated. Since section 4.6.7 requires alterations to meet new construction requirements, you must maintain the 1-hour fire resistive rating. My advice is to repair the smoke compartment walls to their original condition, which is 1-hour fire rated.