Nobody seems to be able to cite with codified certainty what the existing SFD would be in the C of O tables mentioned, I sure can't. I also mentioned in our conversation the numerous times this has been done, who knows what path was taken....in a lot of cases probably a flexible one, including when I have done them in the past. I have never seen one turned into a group E occupancy, which is what churned this whole thread up. I am glad it did, even if we can't agree on some of the conclusions. I suspect in many of the cases where this has been done, the application of the IBC wouldn't have been too difficult, since most I have seen are turned into occupancies that don't exceed allowable stories, areas or heights, and have very low occupant loads. This project is an E, with 45 six-year olds, exceeds the story limitations, has an E fire area on the 2nd floor, no sprinklers, with an FSD issue.
I will paste the two technical opinions below. They are opinions, not code, which I use to inform my own opinions (maybe validate was the wrong term). Would they survive the scrutiny of an official interpretation? Would they survive a code change proposal? No idea. Use or don't use the information as you see fit.
Question:
IEBC tables 1011.4, 1011.5 & 1011.6 show either generic R occupancies or specific R1, R2, R3 or R4 occupancies as a given level of hazard. Since IRC regulated structures are not assigned an IBC occupancy classification, how is a hazard category assigned when using these tables? If using R3 based on 310.4, is it assumed that sprinklers are installed per 903.2.8 and 903.2.8.1 when assigning them a hazard category as an R or R3?
Many IRC regulated homes are not provided with fire sprinkler systems. When changing the occupancy classification to an IBC group from an IRC single family dwelling I am unsure of the path. If it is assumed that R3 is the appropriate designation but the structure is not provided with sprinklers can the referenced tables be used?
Answer:
Based on your e-mail and our conversation, an existing single-family dwelling is to now be used
as a preschool / day care facility. You wish to know if the provisions of Chapter 10 of the IEBC are
applicable to the building.
Single-family dwellings are typically regulated under the International Residential Code (IRC)
while a preschool / day care facility is typically regulated as either a Group E or I-4 occupancy
under the International Building Code (IBC). While single-family dwellings are typically classified
as Group R-3 in accordance with the IBC, they are not considered a Group R-3 occupancy for
purposes of the IRC or for purposes of the IEBC.
While the IEBC addresses buildings undergoing a change of occupancy, a building undergoing a
change from a single-family dwelling to a preschool / day care facility would be considered a
“change of code”. A true “change of code” would require compliance with the applicable
requirements of the IBC. As such, in my opinion, the provisions of Chapter 10 of the IEBC would
not be applicable.
Question:
IEBC 1011.5 directs users to determine the relative hazard of different occupancies based on t1011.5. When it is determined that a change of occupancy to a higher hazard is taking place, IEBC 1011.5.1 instructs that the new occupancy "heights and areas" shall comply with IBC ch. 5. "Heights and areas" is specifically called out, but number of stories is not. Is it intended that the number of stories limitations from IBC ch. 5 also be adhered to even though it is not specified in IEBC 1011.5 or IEBC 1011.5.1?
Answer:
With regards to a change of occupancy, Section 1011.5 refers to the height and area of an
existing building. You wish to know if the building height also includes the number of stories.
Prior to the 2015 International Building Code (IBC), the code simply used the term “building
height”. While the definition of “height, building” refers to the vertical distance from grade plane to
the average height of the highest roof surface, the term has generally intended to apply to the
height in feet as well as the number of stories above grade plane. This issue was mostly clarified
in the 2015 edition of the codes in accordance with Code Change G101-12 (a copy of which is
attached) where several sections of the IBC, as well as a couple of subsequent sections in the
IEBC, were changed to also refer to the number of stories.
As indicated in the Reason statement to the code change, the proposed change rewrites current
IBC allowable area and height provisions in an attempt to provide an increased degree of user
friendliness and technical consistency to these fundamental requirements. Although this proposal
modifies the format and technical language for allowable area and height determination, for all
intents and purposes it can be regarded as being an editorial code change. The code user will
achieve exactly the same design solution in the 2015 IBC using the proposed improved
methodology as that which results from the 2012 IBC.
Section 1011.5 of the IEBC refers to hazard categories in regard to height and area. This section
has been in the IEBC since the initial publication of the 2003 IEBC. The height of a building in
Chapter 5 of the IBC, specifically Section 504, refers to the height, in feet, of a building as well as
the number of stories above grade plane. While a code change to Section 1011.5 of the IEBC
may ultimately be necessary to clarify any possible confusion, it has never been the intent of this
section to only refer to the height in feet and not the number of stories.
