Tom, No, A mixed occupancy building is just that, a combination of many occupancy classifications in one building. The Certificate of Occupancy may list the most significant occupancy however many certificates list each occupancy.
Yes, Each occupancy is weighted against the others. The occupancy that poses the greatest hazard is generally looked at and the most restrictive provisions of the code, i.e. height and area, construction type, egress, fire protection, etc, applied with some exceptions (see below, under special provisions). Yes but not always. There are two major mixed occupancy provisions in the IBC, "Non Separated" and "Separated". Designers will often "run the numbers" both ways to find the most economical method of construction. We require them to declare the method, Non Separated or Separated, this then sets the baseline for how we conduct the review. Just like you do with sprinkler designs, 13, 13R or 13D. Yes, The Special Provisions section of the IBC permits mixed construction types. "Pedestal Buildings" are an example of this. A pedestal building is a good example of a mixed occupancy / mixed construction type building. These are typically S-2 Parking of IA construction with R-2 Residential above of Type V wood frame construction. This is highly debated since the Special Provisions (508 in the 2000 Ed, 509 in the 2006 ed) section of the IBC states; "A basement and/or the first story above grade plane of a building shall be considered as a separate and distinct building for the purpose of determining AREA LIMITATIONS, CONTINUITY OF FIRE WALLS, LIMITATION OF NUMBER OF STORIES AND TYPE OF CONSTRUCTION". Many contend that the grade plane reestablishment DOES NOT apply to fire protection systems such as alarms, sprinklers and standpipes since these items are not identified in the charging statement listed above nor any of the various conditions found in 508.2 thru 508.8. New Jersey has become much more progressive, we are currently adopting the 2006 IBC with State Modifications. However since the Chapter 35 reference standards lag (or lead depending on your point of view) we will be utilizing the 2002 Editions of NFPA-13/13R/13D and NFPA-72, a cycle behind. The NEC stands alone as our electrical subcode so we're already using the 2005 edition which was adopted last year, hats off to the electrical guys. I suggest to everyone to obtain the IBC Commentary, its an invaluable resource. John Drucker Fire Protection Subcode Official New Jersey -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Duross Sent: Saturday, February 10, 2007 5:55 PM To: [email protected] Subject: RE: Residential? Thanks for the clarification John. I printed it and put it in my building code. But doesn't the building still just have a single use group is it's Mixed Use? Then the separated uses are built in accordance to the provisions for area, egress, construction type, etc.? The building codes don't allow for different construction types within the same mixed use building, right? Same as using two fire codes, 13R in the residential and 13 in the commercial for example. I don't mean to stray from the main topic but I think it was focused on the appropriate fire code. We're Boca '93 up here, very similar statutes as IBC. I wish we were more current code-wise, there's a lot more supportive and interpretive information than using a 15 year old building code. Tom Duross Boston -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of John Drucker Sent: Saturday, February 10, 2007 4:45 PM To: [email protected] Subject: RE: Residential? Tom, A building can have many. Buildings are classified with respect to the occupancy (2000 & 2006 IBC Section 302). There are 10 occupancy groups. A number of those groups are broken down further, for example the Assembly Group (IBC Section 303) is broken down in 5 subgroups, A1,A2,A3,A4 and A5. AHJ's look at the proposed and or actual occupancy of a building and classify it accordingly. When an occupancy is not specifically listed in Chapter 3 the occupancy is classified to a group most resembling the fire safety and relative hazard involved. A building that contains more then one occupancy or use 2000 IBC 302.3 / 2006 IBC 508 is applied.titled "Mixed Use and Occupancy". The first step in the process is to determine if any Accessory Occupancies and or Incidental Uses exist. Accessory Occupancies, generally 10% or less of the main occupancy and or Incidental Uses, normally spaces used for special purposes such as mechanical rooms, storage rooms, trash rooms etc. utilize special provisions of the IBC. Incidental Use areas are classified in accordance with that portion of the building in which they are located. Incidental Use Areas require fire rated seperation and or suppression in accordance with Table 508.2.(2006) 302.1.1 (2000). Accessory Occupancies are addressed in IBC 508.3.1(2006) 302.2(2000). Beyond the Incidental and Accessory provisions building designers utilize the Non-Seperated or Seperated Occupancy provisions of the IBC. The former utilizes a formula based on individual occupancy ratios, the later based on rated fire separations. Hope that helps, John Drucker Fire Protection Subcode Official New Jersey -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Duross Sent: Saturday, February 10, 2007 10:59 AM To: [email protected] Subject: Re: Residential? How can a building have 2 use groups? td > Aha, more information.... > > Lets see 1,231 sf > > 50 X 110 = 5,500 sf > > 1231/5500 = 22% > > Mixed Use > > NFPA-13 > > Next Question > > John Drucker > Fire Protection Subcode Official > New Jersey > > > Let's put this in perspective: > One 535 SF classroom > One 312 SF Conf room > One 160 SF Office > Two 106 SF offices > One 118 SF Laundry > That's substantially less than run of the mill hotel back of house. > > Are the business offices of a hotel, not to mention their conference > rooms, > incidental to the running of a hotel? Commercial laundries, not a 7' x 17' > cubby. > > glc > > > To me this sounds like a 13 system. Incidental is defined as "of a > minor, casual or subordinate nature". I'm not sure that offices and > classrooms fall under that category for an otherwise residential > occupancy since that could stand on their own. My thought is that an > incidental occupancy (such as an office or laundry room for a hotel) > is one that could not reasonably exist without the primary > (residential). I vote for mixed use, hence 13. > > At 04:05 PM 2/9/2007, you wrote: > >>We have a project in which the majority of the building is dorm rooms; >>2nd flr (top) is all dorms, with a few more dorm rooms and a few >>classrooms >>and offices on the first floor. Small basement is mechanical only. >>Entire building footprint is a whopping >> >>The classrooms are for the use of the students that reside in the dorm; >>Offices for faculty that teach there. >> >>Overall concept is suburban campus college has this building in the city > for >>students to study government and urban life. So the non-residential areas >>are incidental to the residential nature of the building. >> >>The Architect has deemed the building A3 for the first floor, R2 on 2nd >>floor. Naturally the one hour separation is at the first floor ceiling. >> >>If this sounds a little strange, at least it's not #13TR, elderly housing >>over tire storage:) This IS located in a locale where 13d tank/pumps feed > 3 >>story office buildings, with poly tanks located in restaurant storage >>area, >>and CPVC in OH2. Sure, that will make the judge understand ? >> >>Anyway, would % of use and other uses being for the occupants make this > look >>#13R to any of you? >> >>George Church >>Rowe Sprinkler >> _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
