14. EXCESSIVE AREA
Building codes limit a building's floor area depending on the combined impact of four parameters—these variables are (1) the type and combustibility of the building's construction system; (2) the building's function or occupancy; (3) how close the building is to other structures; and (4) whether the building has an automatic sprinkler system. Such limits, regulated and constrained in chapter 5 of the code, create a 4-dimensional matrix for the determination of floor area (and other) limits, based partly on principles of fire science, partly on the empirical history of buildings and fires, partly on evidence of the effectiveness of automatic sprinkler systems, and partly on the relatively recent political desire to reconcile standards embedded in various competing model codes so that a single, "national code" could be promulgated—i.e., the International Building Code or IBC, developed by the International Code Council.
The parameters that determine allowable areas in chapter 5 of the code are affected by how "the building" is defined, i.e., whether Milstein Hall is considered (1) free-standing, i.e., Milstein only; (2) combined with both of its neighbors, i.e., Milstein-Sibley-Rand; (3) combined with only one of its neighbors, i.e., Milstein-Sibley; or (4) combined with its other neighbor, i.e., Milstein-Rand. These four alternative scenarios for computing allowable floor area are outlined in Table 1. Why and how these scenarios might be implemented will be addressed later. But to begin, we discuss the determination of allowable floor area as shown in Table 1, starting with the top row, and working our way down.1
Table 1: Calculation of allowable second-floor area for A-3 occupancies.
|Milstein only||Milstein, Sibley, and Rand||Milstein and Sibley||Milstein and Rand|
|Tabular area, At, for SM (sq. ft.)||28,500||18,000||18,000||28,500|
|Tabular area, At, for NS (sq. ft.)||9,500||6,000||6,000||9,500|
|Perimeter, P, for frontage (ft.)||1,045||1,190||800||1,135|
|Partial perimeter, F, for frontage (ft.)||328||973||704||766|
|Average width, W, for frontage (ft.)||30||30||30||30|
|Frontage coefficient, If||0.19||0.57||0.63||0.42|
|Allowable area, Aa (sq. ft.)||30,305||21,420||21,780||32,490|
|Actual area (sq. ft.)||26,512||43,954||34,684||35,782|
Construction type. The key distinction among the five main construction types outlined in the building code is whether the building's primary elements of construction are combustible (i.e., whether they include wood framing elements) or noncombustible (i.e., whether they're constructed from pretty much anything else—steel, reinforced concrete, or masonry).
Construction types I and II are noncombustible; Types III, IV, and V are combustible, in that they all can contain wood elements. Once that primary distinction is made, four of the five construction types are further divided into sub-types—A and B—where subtype A has a greater fire-resistance rating on some or all of its components than subtype B. (Type IV construction had only one subtype—"heavy timber," or HT— when Milstein Hall was built. With the development of mass timber and its incorporation, for the first time, into the 2021 IBC, Type IV has been expanded to include three new subtypes, A, B, and C, in addition to the traditional HT.)
Specifications for construction types are found in chapter 6 of the building code. Table 601, in particular, itemizes the required fire-resistance rating of constituent building parts (e.g., primary structural frame, floor and roof construction, etc.) for all construction types.2 There are only two construction types which require no fire-resistance ratings on any of their components—Type IIB (basically non-fireproofed steel framing like Rand and Milstein Halls, assuming that they were not connected to Sibley Hall) and Type VB (basically non-fireproofed light wood framing like Sibley Hall). For this reason, the construction types for all three buildings— Milstein and Rand Halls (IIB) and Sibley Hall (VB)—are objectively the "worst" construction types in terms of fire safety. The code takes this into account when it tabulates and constrains allowable floor areas and building heights.
Only a fire wall between buildings allows those building to be considered separately from their immediately adjacent neighbors, and fire walls were not constructed between Milstein, Sibley, and Rand Halls. For that reason, the combined Milstein-Sibley-Rand Hall constitutes a single building from the standpoint of allowable area calculations, and a single building can only have one construction type. Because Sibley Hall is a combustible wood-framed building with the least fire-resistance of any code construction type, Milstein Hall, in combination with either Sibley and Rand Halls, or just Sibley Hall, is subjected to area limits determined by the weakest link in the combined building complex: Sibley Hall with Type VB construction.
Sibley Hall, with its loadbearing exterior masonry walls, appears at first glance to have more robust construction than Type VB, which is generally associated with entirely combustible wood-frame structures. In other words, having exterior masonry walls would seem to place it in the category of so-called "ordinary construction," i.e., Type IIIB. However, because Sibley Hall's third-floor walls transition from masonry to wood, creating a Mansard roof (fig. 14.1), the building's construction type must be downgraded to type VB. This, in turn, means that the allowable floor area for the combined Milstein-Sibley-Rand Hall must be determined on the basis of Type VB construction.
If Sibley Hall's Mansard wood-framed walls were upgraded to 2-hour fire-rated construction, its construction type would be upgraded to IIIB, allowing increased floor area. However, such an upgrade would apply only to Sibley Hall as a freestanding, independent building, and would have no effect on the construction type of a combined building that included Sibley Hall (i.e., Milstein-Sibley-Rand Hall or Milstein-Sibley Hall). This is because Type IIIB construction requires 2-hour fire-rated exterior bearing walls, which a freestanding (and upgraded) Sibley Hall would have but which a combined building that included Milstein Hall would not have. The only construction type that permits all elements to have no fire-resistance rating and permits combustible elements (i.e., the wood floors and roof framing of Sibley Hall) is VB.
Occupancy group. The building code requires that all spaces in a building be identified in terms of their use-function, since the "occupancy" of a space has important ramifications for fire risk and, therefore, fire safety requirements. This risk can take two forms: first, some occupancies, like lecture halls, or exhibition spaces, may contain lots of people, often packed closely together; second, some occupancies, like storage buildings or libraries, contain large quantities of hazardous (flammable) materials. The code gives each occupancy group a letter designation—e.g., A for assembly, B for business—and, in some cases, a number indicating its subtype—e.g., A-3 for art galleries, libraries, lecture halls, and so on. Taken together, Milstein-Sibley-Rand Hall combines several different occupancy groups, including university classrooms and offices (group B), lecture halls, galleries, and libraries (group A-3), wood-metal shops (group F-1), and even some exterior space below the cantilevered second floor over University Avenue (S-2).
While there can be only one construction type for a single building such as Milstein-Sibley-Rand Hall, there can be multiple occupancies. However, because these multiple occupancies are not consistently separated with fire-resistance-rated walls and floors (fire barriers and horizontal assemblies), the 2002 code mandated that the "required type of construction for the building shall be determined by applying the height and area limitations for each of the applicable occupancies to the entire building" and, in addition, that "the most restrictive type of construction, so determined, shall apply to the entire building."3 This is a rather convoluted way of saying, as the 2020 code clarified, that the "allowable building area, height and number of stories of the building … shall be based on the most restrictive allowance for the occupancy groups under consideration for the type of construction of the building …"4 Milstein, Sibley, and Rand Halls have no fire-rated construction separating their various floors, and each building has group A-3 assembly spaces as follows: Milstein Hall has gallery, exhibition, and auditorium spaces; East Sibley has a large lecture hall; and Rand added a library soon after Milstein Hall was occupied. For this reason, each building's allowable area—even if examined separately—would be governed by the A-3 occupancy group, as shown in Table 1.
Fire barriers—basically fire-rated infill walls between the floor and ceiling of any given story—can be provided in order to separate different occupancies from each other, or divide a single occupancy into separate fire areas, but such fire barriers do not change the underlying construction type of the combined building, which remains that of a combustible wood-frame structure (Type VB). Where mixed occupancies are separated by vertical fire barriers and fire-rated horizontal assemblies in a single building, building codes stipulate that the sum of the ratio of proposed to allowable floor areas for each separated occupancy, in each story, be no greater than 1.0. However, this strategy of creating "separated occupancies" with fire barriers would not be feasible for the combined Milstein-Sibley-Rand Hall, since the combined ratios of proposed to allowable floor areas for the second floor would still come up short, and would, in addition, necessitate the construction of fire barriers and horizontal assemblies separating the Crit Room from studios above, something that might solve the acoustical issues illustrated in figure 4.16, but would also fatally compromise the design intent.
Tabular area (At) for SM and NS. For any specific occupancy group and construction type—where occupancy group and construction type constitute two of the four parameters in the code's 4-dimensional matrix found in chapter 5—modern codes define two tabular allowable floor areas, At, for multi-story buildings, which form the basis for computing the allowable floor area, Aa. SM is the tabular area for multi-story buildings with automatic sprinkler systems; NS is the tabular area for buildings without automatic sprinkler systems. For sprinklered buildings, these tabular values depend only on construction type and occupancy group. Since the occupancy group is taken as A-3 for all four scenarios in Table 1, the tabular values in these two rows of the table are identical for the two Type IIB building scenarios (Milstein alone or Milstein-Rand) and for the two Type VB building scenarios (Milstein-Sibley-Rand or Milstein-Sibley). The 2002 New York State Building Code uses a different, and now obsolete, calculation method based on a single tabular area for non-sprinklered buildings but arrives at the same results.
Perimeter, P, and partial perimeter, F, for frontage. To calculate the "bonus" allowable floor area given to buildings that are relatively far away from other structures, the calculation of a so-called frontage coefficient, called an "area factor increase due to frontage" in the code, starts with the determination of the building's exterior perimeter length (P) and that portion of the perimeter (F) which faces an open space or public way for a distance or width of no less than 20 feet (6.1 m), measured perpendicular to the building. For example, the portion of Milstein Hall's perimeter which faces the Foundry to the north is not counted when computing F, since the distance between the two structures is less than 20 feet (6.1 m) along that portion of Milstein Hall's perimeter (fig. 14.2). Figure 14.3 illustrates the extent of the perimeter, P, and partial perimeter, F, for the four scenarios outlined in Table 1.
Average width, W, for frontage. The crucial parameter in the frontage calculation is the determination of the average width, or distance, measured from the building's perimeter to the farthest point where open space or streets (public ways) preclude the construction of other buildings that might present a fire hazard. According to the International Code Council's Commentary, frontage width "provides access to the structure by fire service personnel, a temporary refuge area for occupants as they leave the building in a fire emergency and a reduced exposure to and from adjacent structures."5 Typically, the width is measured perpendicular from any building face to the property line (for side and rear yards) or to the far side of the right-of-way containing a street (for the front yard). Any perpendicular distance less than 20 feet (6.1 m) is considered too small for that section of the perimeter to be counted in the calculation of the partial perimeter, F. Any perpendicular distance greater than 30 ft. (9.1 m) is considered needlessly large from the standpoint of fire safety, and so the value of 30 ft. (9.1 m) is used as the width for any such sections of the partial perimeter, F, even though the actual width may be larger. The average width for the whole building is found by multiplying the various perimeter segments constituting the partial perimeter, F, by each of their individual widths, and then dividing the sum of those products by the partial perimeter, F.
In the case of Milstein Hall, or any of the four scenarios listed in Table 1, this calculation is rendered moot, since each of the individual widths for the entire partial perimeter, F, is greater or equal to 30 ft. (9.1 m)—and therefore counted as 30 ft. (9.1 m). For this reason, the average width, W, calculated as the sum of the products of segment lengths × 30 ft. divided by the sum of the segment lengths (i.e., F), must be 30 ft. (9.1 m) in all cases.
Frontage coefficient (If). The area factor increase based on frontage is defined as follows, using imperial units: If = (F/P – 0.25) × (W/30). We can make sense of this equation by examining the two parenthetical portions at their extremes. First, looking at (F/P – 0.25), we see that the greatest frontage benefit occurs when no segment of the exterior perimeter is excluded—i.e., when the partial perimeter, F, equals the total perimeter, P. In that case, F/P = 1.0, and the parenthetical expression becomes 1.0 – 0.25 = 0.75. At the other extreme, as defined in the code, only 25 percent of the perimeter qualifies for the frontage bonus, because the width measured from the other 75 percent of the perimeter is less than 20 ft (6.1 m). In that case, F/P = 0.25, and the parenthetical expression becomes 0.25 – 0.25 = 0.
Second, looking at (W/30), we see that the maximum value occurs when the average width, W = 30 ft. (since W can never be taken greater than 30 ft.), in which case (W/30) = 1.0. At the other extreme, the smallest possible value for W is 20 ft., since any width less than 20 ft. is excluded from consideration. The minimum value is therefore (20/30) = 0.67. Putting the two parenthetical extremes together, we get a maximum value for If = (0.75) × (1.0) = 0.75; and a minimum value for If = (0) × (0.67) = 0. In other words, the values for the frontage coefficient range from 0 to 0.75, with the minimum value corresponding to a building without sufficient frontage to qualify for any bonus, and the maximum value of 0.75 corresponding to a building with at least 30 ft. (9.1 m) frontage on all four sides.
Milstein Hall, in any of the four scenarios outlined in Table 1, will have a frontage coefficient somewhere between 0 and 0.75, depending on the ratio of F to P in the first parenthetical portion of the equation. In all four cases, the second parenthetical expression will be (30/30) = 1.0 since the width measured from all qualifying perimeter segments is greater or equal to 30 ft. (9.1 m).
Allowable area (Aa). The allowable area is based on the two tabular areas and the frontage coefficient, as follows: Aa = At + (NS × If ). In this equation, At is the tabular value for SM (since Milstein Hall and its variants are all multi-story buildings with automatic sprinklers), NS is the tabular value for a building without automatic sprinklers, and If is the frontage coefficient. It may seem puzzling why NS, the tabular value for a building with no sprinklers, is used in this calculation for a building with automatic sprinklers. The rationale was clearer in prior versions of the code, when there was only a single tabular value listed for non-sprinklered buildings (what is now called NS) and the calculations for allowable area were based on that single tabular value: an area bonus for having a multi-story sprinklered building was found by multiplying the tabular value by 2; a bonus for frontage was computed by multiplying the same tabular value by the frontage coefficient; and these two "bonus" values were added to the tabular value to arrive at the allowable area. In the current codes, separate tabular values were added for single-story sprinklered buildings (S1) and for multi-story sprinklered buildings (SM), but the bonus for frontage was, as before, based on the tabular value for a non-sprinklered building. Hence the continued use of NS for frontage calculations, whether or not the building in question has automatic sprinklers. The allowable floor area applies, not to the whole building, but to any given floor—in our analysis, we examine the second floor, because it has the largest floor area.
Actual area. The actual second-floor areas for Milstein Hall, either taken alone or in combination with Sibley and/or Rand Halls, are found based on the same perimeter dimensions that were used in the frontage calculations (Figure 14.2). These actual areas must be compared with the allowable areas that were computed on the basis of construction type, occupancy group, sprinklers, and frontage. It may be self-evident, but I'll say it anyway: actual areas cannot exceed allowable areas. If they do, the building becomes noncompliant, and a building permit cannot be obtained. More importantly, a building whose actual floor area exceeds the allowable area specified in the building code is considered unsafe.
Floor areas were first regulated in the early eighteenth century: limits of 3,500 square feet (325 square meters) with a maximum volume of 210,000 cubic feet (5,947 cubic meters) can be found in Great Britain's Building Act of 1744.6 The rationale for such limits has not changed substantially since then, even if new technologies, especially automatic sprinklers, have increased those limits in some circumstances. J.K. Freitag outlined the rationale in his compendious early-twentieth-century Fire Prevention and Fire Protection Handbook:
It has been pointed out that the volume and intensity of fire, and the rapidity with which it will gain headway, are all vastly greater in large areas than in small ones. It is also a much more difficult matter for a fire department effectively to surround and fight a fire of large area. Much valuable time is lost in running long lines of hose, in addition to which, smoke conditions are often so bad that the actual location of the fire cannot either be found, or reached if found. There is a limit to the ability of firemen to inhale smoke or withstand heat, and once this limit is reached, the offensive operations of extinction cease, the firemen are put on the defensive, and the fire is master of the situation. These considerations would point to the desirability of fixing what might be termed the maximum area which can be efficiently handled by a city fire department. "As a working unit, 5,000 square feet has been suggested, with a limit of 100 feet in any direction (or a rectangle of 50 by 100), which is as large an undivided area as the experience of the New York Fire Department indicates to be within the capacities of effective fire department operations."7
This suggested floor-area limit of 5,000 square feet (465 square meters) is only slightly larger than historical limits written into the Building Act of 1744. However, by the mid-nineteenth century, a work-around was articulated that made it possible for floor areas to exceed the stipulated limits. The 1844 Metropolitan Act in London provided that "if such Building contain more than 200,000 Cubic Feet,—then such Building must be divided by Party-Walls, so that there be not in any one Part of such Building more than 200,000 Cubic Feet without Party-Walls."8 The term, "party wall," as used in the 1844 law, is equivalent to what modern codes call fire walls9 (whereas a modern party wall is defined as a specific type of fire wall that is built on the lot line between adjacent buildings). The strategy of building a fire wall, articulated in 1844, remains the only way to exceed area limits, even in modern building codes: fire walls can subdivide a building into smaller pieces, effectively creating separate buildings, each with a compliant floor area.
As can be seen by examining the bottom two rows of Table 1, the combined Milstein-Sibley-Rand Hall's actual second-floor area of 43,954 square feet (4083 square meters) is more than double the allowable area of 21,420 square feet (1990 square meters). The only scenario in which the actual area does not exceed the allowable area is when Milstein Hall is considered as an independent, stand-alone, building, requiring the construction of fire walls to separate the three buildings. Any other scenario, either combining Milstein Hall with both Sibley and Rand Halls without any fire walls, or using just a single fire wall between Milstein Hall and one of its neighbors—i.e., building a fire wall between Milstein and Rand Hall, thereby combining Milstein Hall and Sibley Hall into a single building; or building a fire wall between Milstein and Sibley Hall, thereby combining Milstein Hall and Rand Hall into a single building—is noncompliant, since the actual floor areas exceed the allowable areas in those cases.
Fire walls separating Milstein Hall from both Sibley and Rand Halls constitute the only possible strategy to rescue Milstein Hall's formal design concept from this apparently fatal flaw:10 Milstein Hall must not only be separated from the limiting wood-frame construction type of Sibley Hall, but also separated from the non-fireproofed steel construction of Rand Hall.
There is nothing particularly unusual about using fire walls to, in effect, divide a single building (from a fire code standpoint) into two or more separate buildings, each with its own area, story, and height limits determined in each case by its own construction type, occupancy, and so on. If fire walls had been built between Milstein Hall and its neighbors, Sibley Hall would have been permitted to remain as a nonconforming Type VB sprinklered building, Rand Hall could have remained as a noncombustible Type IIB sprinklered building, and Milstein Hall could have been built as an independent, noncombustible Type IIB sprinklered building meeting all requirements for floor area.
The problem is that, unlike a fire barrier, a conventional fire wall is difficult to build. First, it must "extend from the foundation to a termination point not less than 30 inches (762 mm) above both adjacent roofs"11 (with some alternative arrangements or exceptions listed in the code, none of which make the construction any easier). That is, a fire wall cannot merely fill the spaces between stories like a fire barrier, but must be independent and continuous from the bottom to the top of the building. Second, a fire wall must "have sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall for the duration of time indicated by the required fire-resistance rating."12 This is never easy to do with a single wall, especially since Milstein Hall was designed to be structurally separated from Sibley and Rand Halls to enable translation (lateral movement) when subjected to seismic forces. In other words, it would be extremely difficult to design Milstein Hall so that it could stabilize the exterior masonry walls of Sibley and Rand Halls should their floor construction collapse in a fire, and simultaneously maintain a 5-inch (127 mm) separation, i.e., a seismic isolation joint.
There is, however, an alternative, especially useful when constructing additions to existing buildings. The IBC permits "double fire walls" instead of conventional (single) fire walls, built according to specifications outlined in the National Fire Protection Association publication, NFPA 221.13 Basically, this entails building two 1-hour walls separating Milstein and Sibley Halls, equivalent to a standard two-hour fire wall; and building two 2-hour walls separating Milstein and Rand Halls, equivalent to a standard three-hour fire wall. The separation between Milstein and Rand Halls needs greater fire resistance than the separation between Milstein and Sibley Halls because the wood shop in Rand Hall, with occupancy group F-1, triggers this higher value.14 Building a double fire wall would have been relatively easy to implement because the exterior masonry walls of Sibley and Rand Halls are already almost acceptable as one of the two walls needed in a double fire wall—they are already built, and they already have adequate fire resistance once their windows and doors are upgraded. Therefore, all that would have been required is the construction of a second fire-rated wall, parallel to the existing masonry walls of Sibley and Rand Halls, that would be part of, and connected to, Milstein Hall. Since each wall would remain in place and provide fire protection if the other wall collapsed, the onerous requirement that applies to a single fire wall—to remain stable if the structure on either side collapses—is moot. This second wall, however, would cover up the existing masonry walls of Rand and Sibley Halls, walls that are currently visible from the interior of Milstein Hall. This might have some expressive ramifications, in that the diagrammatic ideal of Milstein Hall as an abstract connector, an unimpeded circulation link between Sibley and Rand Halls at the second-floor level, would be compromised—even if the practical requirements for circulation would remain unchanged. Putting a new wall up against the back side of Sibley Hall might also upset the Ithaca Landmarks Preservation Committee, whose approval is needed (Rand Hall was excluded from the local historic district to enable its demolition per the initial competition brief for Milstein Hall, a competition won by Steven Holl in 2001).
In any case, fire walls between Milstein, Sibley, and Rand Halls were never specified and never built. Without fire walls, and with an actual floor area more than twice the allowable floor area, the design for Milstein Hall should have been stopped in its tracks. In fact, discussions among the "design architects" (OMA), the architects of record (KHA) and the Ithaca Building Department (Ithaca Deputy Building Commissioner Mike Niechwiadowicz), show that the "fire wall" question was discussed well before the design was finalized, more than two years before an application for a building permit was filed, and more than four years before construction started. In March 2005, the Deputy Building Commissioner offered the architects a choice of creating separate "fire areas" using fire barriers, or isolating Milstein Hall as a separate building using fire walls: "I do believe we can go with separate fire area, which would mean it is all one building… The separate building would require a fire wall."15 Yet a year later, in March 2006, a code summary prepared by KHA, the architect of record, questioned whether the code logic of merely using fire barriers was sound: "I do not see how an addition of the proposed size [i.e., Milstein Hall] can be incorporated since Sibley currently exceeds the allowable area for Type 5 construction and the new construction to be inserted would increase the size."16
During the next year, apparently with the support and active encouragement of the Deputy Building Commissioner, the fire barrier strategy was adopted. Justification for an increased allowable floor area, beyond what would have been permitted under chapter 5 of the building code without providing fire walls, hinged on a superficial and overly generous reading of an unprecedented and flawed document: Appendix K in the 2002 New York State Building Code. But the apparent loophole available through Appendix K was about to expire with the adoption of the 2007 New York State Building Code on January 1, 2008. Rather than recognizing that the proposal was seriously flawed from a fire safety perspective, was enabled by a contradictory and absurd document, and would be nonconforming with the soon-to-be-adopted 2007 New York State Building Code, the architects filed an application for a building permit with the Ithaca Building Department on May 18, 2007, in order to obtain a building permit based on the 2002 code containing Appendix K.
This timeline is important: the application for a building permit was filed six months before the new code was to be implemented,17 it was filed in violation of regulations requiring a complete and compliant set of working drawings,18 and it was filed well before construction of Milstein Hall was set to begin. In fact, a building permit wasn't issued for another year and a half, and construction didn't start until the summer of 2009, two full years after the building permit application was filed. That a building permit was actually issued, given the unresolved and noncompliant status of its fire safety strategy, is something that can only be explained by the Ithaca Code Enforcement Officials who granted the permit (fig. 14.4).
Ithaca's Deputy Building Commissioner argued that Appendix K, a unique and unprecedented provision that applied only to the 2002 New York State Building Code and that was set to expire on January 1, 2008, would permit additions to existing buildings to exceed floor areas ordinarily constrained by those chapter 5 provisions in the building code that were outlined above—as long as a fire barrier (not a fire wall) was provided. The relevant language in section K902.2 of Appendix K consists of a single sentence: "No addition shall increase the area of an existing building beyond that permitted under the applicable provisions of chapter 5 of the Building Code for new buildings, unless a fire barrier in accordance with section 706 of the Building Code is provided."19 In all other codes, additions can increase the floor area of an existing building only if a fire wall (not a fire barrier) is constructed between the existing building and the addition, effectively re-defining the "addition" as a separate building with its own construction type and occupancy group.
Requiring the use of fire walls in such cases is consistent with all other sections of the code and presents no contradictions. But when "fire barrier" replaces "fire wall" in this context, as was done in Appendix K, confusion and contradiction abound. Let's examine the single sentence carefully by inverting its clauses: If a fire barrier separates an existing building from an addition, then the area of the existing building can be increased beyond the limits specified in chapter 5 of the code. Chapter 5 of the code, as we saw above, determines allowable areas by considering the interaction of four parameters: construction type, occupancy group, sprinklers, and frontage. When separated by a fire wall, an addition effectively becomes a separate building, and its allowable area can be determined separately from that of the existing building, based on its own construction type, occupancy group, sprinklers, and frontage. But with a fire barrier, the addition and existing building remain combined as a single building with a single construction type. Under Appendix K, the allowable area is simply increased, without any apparent bounds, beyond the limits specified in chapter 5. To find out how, and if, the area allowed by Appendix K is constrained in any way, we need to examine the last part of its one-sentence definition that requires "a fire barrier [provided] in accordance with section 706 of the Building Code."
Section 706 (Fire barriers) in the 2002 code begins with a general statement of purpose: "Fire barriers used … to separate different occupancies or to separate a single occupancy into different fire areas, shall comply with this section."20 And to comply with this section, the specification of fire-resistance rating for fire barriers, used to separate occupancies and fire areas, must be followed. The specifications in section 706 (Fire Barriers) are as follows: "Where the provisions of Section 302.3.3 are applicable, the fire barrier separating mixed occupancies or a single occupancy into different fire areas shall have a fire-resistance rating of not less than that indicated in Section 302.3.3 based on the occupancies being separated."21 In other words, section 706 directs us to check section 302.3.3 for the appropriate fire rating, but only when "the provisions of Section 302.3.3 are applicable."
The required fire rating, found in Table 302.3.3 "Required Separation of Occupancies (Hours)" for the separation of an A-3 occupancy from another A-3 occupancy, is 1-hour. This is based on a tabular value of 2-hours and an exception which allows the tabular value to be reduced by 1 hour where the building is sprinklered. This much is relatively straight-forward. However, as argued below, the requirement that "the provisions of Section 302.3.3 are applicable" is not met in Milstein Hall, so the use of any fire barrier to increase the area of an existing building with an addition is simply not permitted.
Section 302.3.3 of the 2002 New York State Building Code regulates so-called separated uses, i.e., occupancy groups that are separated from each other by fire barriers and/or horizontal assemblies. The key provision of this section—a provision that must be satisfied in order to use fire barriers as proposed in Milstein Hall based on Appendix K—is as follows: "In each story, the building area shall be such that the sum of the ratios of the floor area of each use divided by the allowable area for each use shall not exceed 1."22 As shown in the right-hand column of Table 2 (assuming A-3 occupancies and Type VB construction), the sum of the ratios of floor area divided by allowable area exceeds 1, and the building is noncompliant.
The building remains noncompliant (the sum of the ratios still exceeds one) even if the construction type for the single Milstein-Sibley- Rand building is taken as IIB (i.e., if Sibley Hall is magically upgraded to a non-fireproofed steel-frame building just like Milstein and Rand Halls), as shown in Table 3.
Table 2: Separated use calculations with Type VB construction and A-3 occupancy.
|Milstein Hall||Sibley Hall||Rand Hall||Sum (total)|
|Actual area||26,512 sq. ft.||8,172 sq. ft.||9,270 sq. ft.|
|Allowable area||21,420 sq. ft.||21,420 sq. ft.||21,420 sq. ft.|
Table 3: Separated use calculations with type IIB construction and A-3 occupancy.
|Milstein Hall||Sibley Hall||Rand Hall||Sum (total)|
|Actual area||26,512 sq. ft.||8,172 sq. ft.||9,270 sq. ft.|
|Allowable area||33,915 sq. ft.||33,915 sq. ft.||33,915 sq. ft.|
The error made by the building's architects, sanctioned by the Ithaca Building Department, was to assume that each fire area created by fire barriers between Milstein, Sibley, and Rand Halls can be designed not only according to its occupancy, but also according to its individual construction type. But only a fire wall—not a fire barrier—creates separate buildings, each with its own construction type. And only a fire wall permits the evaluation of allowable area for each individual fire area considered separately, rather than the evaluation of allowable area based on the combined fire areas when separated by fire barriers.
Other than these references to section 706 (Fire Barriers) and section 302.3.3 (separated uses), there is nothing in Appendix K that provides any guidance as to how the increased area it appears to permit with fire barriers should be regulated or limited. Furthermore, while Appendix K was promoted as a state-of-the-art reform of existing building regulations based on work already found in the New Jersey Rehab Code23 and the "Nationally Applicable Recommended Rehabilitation Provisions" (NARRP)24 prepared for the U.S. Department of Housing and Urban Development in 1997, the specific provision in New York's Appendix K allowing fire barriers to "increase the area of an existing building" has no precedent in either of these documents. Not only that, every other building code—including the old pre-IBC New York State Building Code, including all subsequent New York State Building Codes (i.e., 2007, 2010, etc.), including all editions of the International Building Code and International Existing Building Code, and including both the New Jersey Rehab Code and NARRP—every single code prevents additions to existing buildings from using fire barriers to exceed floor area limits. Only a fire wall (not just a fire barrier) can effectively create two separate buildings in which different construction types apply. The original transcripts of the New York State Code Council's deliberations—this is the group empowered to maintain and update the New York State Building Code—contain not a single word of text describing or explaining this unique and peculiar section of Appendix K in the 2002 New York State Building Code. Nor have any of numerous experts, many of whom actually served on the Code Council that developed Appendix K, any knowledge or recollection of how or why this unprecedented section was included, or how it ought to be interpreted.25
Given that no other code, past or present, has ever permitted a fire barrier to increase the size of an existing building beyond the limits permitted under normal building code provisions, and given that every other code, past or present, requires that a fire wall be used to increase the area of an existing building beyond the limits prescribed in the codes, it is possible that the language in Appendix K was included in error. For example, the requirements in the two codes that served as models for Appendix K both require fire walls in such circumstances. The New Jersey Rehab Code states: "No addition shall increase the area of an existing building beyond that permitted under the applicable provisions of the building subcode unless a fire wall is provided in accordance with Section 705 of the building subcode."26 The NARRP states: "No addition shall increase the area of an existing building beyond that permitted under the applicable provisions of chapter 5 of the Building Code for new buildings unless fire separation as required in the Building Code [i.e., a fire wall] is provided."27 Both of these codes require a fire wall, not a fire barrier, where additions to existing buildings increase the floor area beyond that permitted under relevant provisions of the building code. Milstein Hall, it bears repeating, would not have been compliant under the 2007 New York State Building Code which became effective on January 1, 2008—a year before a building permit was issued and a year and a half before construction started—because this code contained explicit language requiring a fire wall in such circumstances.
Because Appendix K does not specify how the increased area of the combined Milstein-Sibley-Rand Hall should be regulated when a fire barrier is provided, except by reference to other applicable sections of the code which would prohibit the construction of Milstein Hall as an addition separated by a fire barrier, the entire premise of combining these three buildings based on Appendix K is problematic. The building's architects claimed that the fire barrier separating Milstein Hall from the existing buildings to which it connects permits Milstein Hall to be effectively designed as a separate building, with its own construction type. Yet there is nothing in Appendix K which supports such an assumption, and everything else in the code contradicts such an assumption.
Thomas Hoard, Cornell's code consultant for a separate proposed occupancy change to Milstein-Sibley-Rand Hall, had a different justification for exceeding the floor areas allowed in the code: he agreed that the combined Milstein-Sibley-Rand Hall is actually a single building, but claimed that the combined building had multiple construction types separated by fire barriers:
To summarize, Professor Ochshorn is correct that the construction of Milstein Hall has resulted in the combining of West Sibley, Sibley Dome, East Sibley, Milstein, and Rand into a single building, because they are separated by fire barriers rather than fire walls. However, he did not consider that the combined building is a mixed occupancy building with five separate fire areas, each of which meets the allowable fire areas with permitted area and height increases for sprinkler protection and frontage increases, as shown in the following chart:28
|Building, Construction Type, Use||Basic Allowable Area per BCNYS Table 503||Frontage increase per BCNYS 506.2||Sprinkler increase per BCNYS 506.3||Total Allowable Fire Area|
|East Sibley, VB, A-3||6,000||0%||0||200%||12,000||18,000|
|Sibley Dome, IIIB, A-3||9,5000||25%||2,375||200%||19,000||30,875|
|West Sibley, IIIB, B||19,000||50%||9,500||200%||38,000||66,500|
|Milstein, IIB, A-3||9,500||25%||2,375||200%||19,000||30,875|
|Rand, IIB, A-3||9,500||25%||2,375||200%||19,000||30,875|
But Hoard's interpretation of the Code cannot be sustained: the allowable area for each part of the single building, Milstein-Sibley-Rand Hall, cannot be calculated as if it were, itself, a single building. Once you accept that the fact that Milstein, Sibley, and Rand Halls have been combined into a single building separated into fire areas with fire barriers, then the calculation of allowable areas is based on the sum of the ratio of actual to allowable areas for the three sections, as specified in section 302.3.3 of the 2002 New York State Building Code for "separated uses"—and reiterated in every subsequent code developed by the ICC.
For code-savvy and attentive readers who have made it this far, there is one more clarification to make. In modern building codes based on the IBC, the section on separated uses has been moved from chapter 3, where it appeared in the 2002 New York State Building Code along with other issues pertaining to occupancy, to chapter 5, where it could more directly inform the determination of building heights and areas. Allowable area limits for additions—found by following the instructions in Appendix K to create a fire barrier on the basis of section 706, which, in turn, requires compliance with section 302.33 (separated uses) in chapter 3—would therefore have become meaningless if the section concerning separated uses had been in chapter 5, as it is in modern iterations of the code. This is because Appendix K states that all "applicable provisions of chapter 5" are superseded if "a fire barrier in accordance with Section 706" is provided. Because the modern section on fire barriers still requires that the applicable requirements for separated uses— now in chapter 5—are met, this thought experiment would collapse into a classic Catch 22 paradox: the area limits in chapter 5, including those based on separated uses, would be superseded; but using fire barriers to increase the existing buildings' area beyond the limits in chapter 5 would require those area limits in chapter 5 that are based on separated uses be met, i.e., not superseded.
The largely incoherent and inconsistent section of Appendix K that attempted to lower standards for adding area to existing buildings by substituting the word, "fire barrier" for the word "fire wall," only becomes plausible because separated use provisions are in chapter 3, rather than chapter 5. But the irony is that, by taking the instructions in Appendix K literally and following the trail of referenced instructions from section 706 to section 302.33, the requirements for allowable area, for additions to existing buildings that are separated by fire barriers, are the same as they would be using any conventional code. Code standards were not actually weakened since, as is the case in all other codes, only a fire wall allows the area in an addition to exceed the allowable area of the combined building without a fire wall.
But none of this logic entered into the determinations of the architects and building department. They simply embraced the incoherence of Appendix K and designed Milstein Hall as if it were a separate building, with its own construction type and its own separate area, rather than an addition constrained by uses separated by fire barriers.
Even if one accepts the mistaken premise that Milstein Hall can be designed as if it were a separate building with its own construction type, occupancy group, and allowable area, the lack of adequate fire separation distance between Milstein and Sibley Halls makes the combustible woodframed third-floor wall of Sibley Hall noncompliant (fig. 14.5).
The 2002 New York State Building Code (specifically, section 704.10 "Vertical exposure") requires that "opening protectives" be provided "in every opening that is less than 15 feet (4572 mm) vertically above the roof of an adjoining building or adjacent structure that is within a horizontal fire separation distance of 15 feet (4572 mm) of the wall in which the opening is located."29 All of the window openings in the third floor of Sibley Hall that overlook Milstein Hall qualify under this section for opening protectives. The only exception to this requirement is where the roof construction below the openings has a 1-hour fire-resistance rating and its structure (i.e., the steel beams and girders supporting the roof) has a 1-hour fire-resistance rating. Milstein Hall's roof structure has no fire-resistance rating, so the exception does not apply.
Not only would Sibley's third-floor windows require opening protectives, but the entire exterior wall on the third floor of Sibley (facing Milstein Hall) would need to be reconstructed with a 1-hour fire-resistance rating. Footnote f in Table 601 of the 2002 code (exterior bearing walls) requires that the fire-resistance rating of the wall be not less than that based on fire separation distance (Table 602). Table 602, in turn, requires a 1-hour fire-resistance rating for Occupancy Groups A or B if the fire separation distance is less than 5 feet (1.5 m). The fire separation distance between Sibley and Milstein Halls is 0 feet (0 m), since the two buildings are physically connected.
If a fire barrier between Milstein and Sibley Halls is seen as replacing a fire wall that "serves as an exterior wall for a building and separates buildings having different roof levels [as is the case with the Milstein- Sibley fire barrier—see figure 14.5], such wall shall terminate at a point not less than 30 inches [792 mm] above the lower roof level, provided the exterior wall for a height of 15 feet [4.6 m] above the lower roof is not less than 1-hour fire-resistance-rated construction from both sides with openings protected by assemblies having a 3/4-hour fire protection rating."30 The third floor of Sibley Hall does not meet this criteria.
The architects of Milstein Hall have apparently decided to have it both ways: i.e., to design Milstein-Sibley-Rand as a single building, but to calculate allowable areas on the basis of fire areas, separated by fire barriers, as if each fire area were a separate building. Not only does this violate basic building code principles (since the allowable area of a building with separated uses must account for the sum of the ratios of actual to allowable area for all the separated fire areas), but there is absolutely nothing in Appendix K, or anywhere else in the 2002 New York State Building Code, that supports such an interpretation. Appendix K does not say that a fire barrier can act as a fire wall. It does not say that a fire barrier in this context can create two (or three) separate buildings, each with its own construction type. It says absolutely nothing about how the increased area that it appears to permit should actually be determined, except by reference to the section in chapter 3 on separated uses. Allowing fire barriers to effectively create separate buildings, with separate construction types, and then permitting those separate buildings to violate fire separation distance requirements established for separate buildings (or for separate structures on a single site, or for stepped buildings with fire walls) cannot be justified by any specific text in Appendix K and makes Milstein Hall less safe than it could have been and should have been.
1 ICC, "506 Building area," Building Code of New York State, 2020. The computational method to determine building and floor area in the 2020 code is different from that in the 2002 New York State Building Code, but the results are identical. I've used the newer code here since it may be more familiar to modern readers and is available online. In the 2020 code, the tabular data for allowable area is found in Table 506.2, and frontage increases are discussed in section 506.3. In the 2002 code, tabular data for allowable area are found in Table 503 (Allowable Height and Building Areas), and area modifications in section 506. The difference in method is essentially this: the 2002 code used a single tabular area value for non-sprinklered buildings and provided multipliers for single-story or multi-story sprinklered buildings, whereas the 2020 code provides separate tabular values for non-sprinklered, single-story sprinklered, and multi-story sprinklered buildings. In addition, the 2002 code used a single table for allowable area, height, and number of stories, whereas the 2020 code has separate tables for each of those parameters.
2 ICC, "Chapter 6 Types of Construction," Building Code of New York State, 2002. See, in particular, Table 601.
3 ICC, "302.3.2 Nonseparated Uses," Building Code of New York State, 2002, 18.
4 ICC, "508.3 Nonseparated occupancies," Building Code of New York State, 2020.
5 ICC, Code and Commentary, 5-21.
6 "…the 1774 Act permitted buildings of the first rate to be up to 60 feet in height and 35 squares [3,500 square feet], which equates to 210,00 cubical feet. This limit likely relates, through experience of the fire brigade, to the total quantity of combustibles and subsequent fire expected within an unbroken space." "The Historical Development of the Building Size Limits in the National Building Code of Canada," Sereca Consulting Inc., The Canadian Wood Council (March 19, 2015), here.
7 Freitag, Fire Prevention and Fire Protection, 308. The quote within this block quote is attributed to the Journal of Fire (July 1906), 8.
8 Gibbons, The Metropolitan Buildings Act, 128.
9 I'm using the International Building Code (ICC) spelling of "fire wall" as two words, rather than the commonly used single word, firewall.
10 Without fire walls, even if the construction type of the combined building was IIIB (i.e., if Sibley Hall's Mansard roof was upgraded to 2-hour fire-rated construction and if Milstein and Rand Halls" exterior walls somehow turned into fire-rated bearing walls) or IIB (i.e., if all of Sibley Hall's combustible wood floors, roof, and Mansard walls somehow became noncombustible), the combined Milstein-Sibley-Rand Hall would still have an actual floor area that exceeded its allowable floor area.
11 "705.6 Vertical continuity," ICC, Building Code of New York State, 2022, 90–91.
12 "705.2 Structural Stability," ICC, Building Code of New York State, 2002, 89.
14" Table 706.4 Fire Wall Fire-Resistance Ratings," ICC, Building Code of New York State, 2020.
15 Telephone conference meeting (Mar. 3, 2005), in "Addendum to Application," 70.
16 "Building Code Summary" prepared by KHA, (March 28, 2006), in "Addendum to Application," 70.
17 "The requirements for fire walls between new and existing construction will be difficult to achieve with the design of Milstein Hall so 50% CD documents will be submitted to the City for review before 1 August 2007 when the new code is expected to be adopted." KHA Architects, "I. Building Construction and Separation, Building Code and Fire Protection Meeting Report" (March 13, 2007), in "Addendum to Application," 71.
18 Although the current (at the time of this writing) version of §1203.3 has been revised since Milstein Hall obtained its building permit, the essential requirements are the same: "Each authority having jurisdiction shall include in its code enforcement program provisions requiring an application for a building permit, or an amendment thereto, to include information sufficient to enable the authority having jurisdiction to determine that the intended work accords with the requirements of the Codes. … The authority having jurisdiction shall not approve required construction documents unless they show in sufficient detail that they contain the information and/or documentation required by the applicable provisions of either or both of the Codes…" For New York State "Minimum features of a program for administration and enforcement" of building permits, see 19 NYCRR Part 1203, §1203.3, .
19 "K902.2, Appendix K," New York State Building Code, 2002, 729. The reference to section 706 simply links Appendix K's requirement for a fire barrier to the specifications for fire barriers elsewhere in the building code and lends no additional coherence to the single sentence constituting this section of Appendix K.
20 ICC, "706.1 General," New York State Building Code, 2002, 91.
21 ICC, "706.3.5 Separation of Occupancies and Fire Areas," New York State Building Code, 2002, 92.
22 ICC, "302.3.3 Separated Uses," New York State Building Code, 2002, 18.
23 New Jersey Rehab Code.
24 NAHB Research Center, Inc., et al., "Nationally Applicable Recommended Rehabilitation Provisions" (NARRP), U.S. Department of Housing and Urban Development, Office of Policy Development and Research (May 1997), here.
25 Conclusions about the difficulty of tracing the origin and rationale for the "fire barrier" vs. "fire wall" anomaly in Appendix K are based on my own research at the New York State Dept. of State Division of Code Enforcement and Administration (DCEA), One Commerce Plaza, 99 Washington Avenue, Suite 1160, Albany, New York 12231, on Oct. 31, 2011. While my examination of New York State Code Council transcripts was fairly comprehensive, it is possible that some written explanation eluded my search. On the other hand, my subsequent conversations with numerous experts, some of whom served on the Code Council, validates my initial conclusion: no one was able to explain the anomaly. These experts include Michael Auerbach and Cathy Karp of the DCEA, Melvyn Green (worked on NARRP and is an expert on the history of code provisions for existing buildings), and Gary Higbee (a staff member who chaired the subcommittee that wrote Appendix K).
26 New Jersey Rehab Code.
27 "Nationally Applicable Recommended Rehabilitation Provisions."
28 Thomas D. Hoard, Codes Analyst for HOLT Architects, P.C. in letter to Peter Turner, Assistant Dean for Administration, College of Architecture, Art and Planning, Cornell University (Sept. 6, 2011), copied to Mike Niechwiadowicz, City of Ithaca Building Department, and Graham Gillespie, HOLT Architects, here.
29 ICC, "704.10 Vertical Exposure," New York State Building Code, 2002, 88.
30 ICC, "705.6.1 Stepped Buildings," New York State Building Code, 2002, 91.