© 2012 Jonathan Ochshorn
From the Critique of Milstein Hall introduction: Milstein Hall at Cornell University, designed by Rem Koolhaas and OMA, is an interesting building, in some ways an amazing building, and, by virtually any conceivable objective criterion, a disaster. That something amazing can simultaneously be a disaster is hardly a paradox. In fact, disasters are often amazing, and our amazement often increases proportionally with the range and scope of the disaster.
I will not be criticizing the visual appearance of this building, or making judgments about its subjective, aesthetic merit. I personally find the building interesting, and its underlying formal rationale provocative and compelling. But I am not particularly qualified to render such judgments, and other authorities or connoisseurs of architectural taste may well disagree. What follows, instead, is an objective critique of Milstein Hall, looking at the building in some detail from a series of different points of view, none of which are driven by aesthetic considerations.
From the Fire Safety introduction: "The initial schematic design for Milstein Hall… was fundamentally flawed from a fire-safety standpoint, and should not have been approved for design development. These problems… go to the very heart of fire safety regulations: the requirement that combustible material that might fuel a fire must be limited in quantity so as to preserve life safety and limit property damage in the event of a fire; the compartmentation of buildings into smaller units separated by continuous or protected assemblies; and the provision of adequate means of egress. Six instances of fire-safety Code noncompliance are discussed in the following sections."
Building codes limit a building's floor area, number of stories, and height depending on the combined impact of several parameters—these variables include the type and combustibility of the building's construction system, the building's function (occupancy), how close the building is to other structures, and whether the building has an automatic sprinkler system. Such limits are 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).
All of this fire science and experience is distilled into a single matrix with occupancy groups (e.g., residential, business, educational, etc.) defining one axis and construction types (e.g., noncombustible fire-rated, heavy timber, non-rated wood-frame, etc.) defining the other. For any specific occupancy group and construction type, one can find the basic, or "tabular," allowable floor area, the maximum number of stories permitted, and the maximum allowable height above grade. Including increases for automatic sprinkler systems and distance from other buildings ("frontage"), both of which make buildings safer and therefore permit greater floor area, stories, and height, a fire-safety matrix can be constructed for Milstein Hall (see Table 1).
|Group||Type of Construction|
|II-B (noncombustible, non-fire-rated)||III-B (combustible, 2-hr exterior walls)||V-B (combustible, non-fire-rated)|
|A-3 (Library or large lecture hall)||35,625||35,625||22,500||B (University classrooms or offices, etc.)||86,250||71,250||33,750|
In all such code-based systems, new and old, wood-framed combustible buildings cannot be built as high, or with as much floor area, as can noncombustible buildings constructed of steel, reinforced concrete, or masonry. By proposing to physically connect Milstein Hall to Sibley Hall—a Type V-B combustible wood-framed building with the least fire-resistance of any Code construction category—Milstein Hall became, in effect, a mere addition to an existing building, and was thereby subjected to all the height and area limits determined by the weakest link in the combined building complex: those of Sibley Hall. This is a basic and well-established principle for all buildings, and the maximum floor area is easily found. Given a V-B Construction Type (combustible wood frame) and an Occupancy Group that is primarily Group B (educational occupancies above the 12th grade) but governed by the more limiting Group A-3 functions—since these existing A-3 spaces (libraries, lecture Halls, and auditoriums) have no adequate fire-rated separation from Group B functions in East Sibley Hall—the allowable building area for any floor is, at most, 22,500 square feet.2
The second floor of Milstein Hall, all by itself, exceeds this floor area limit (see Figure 1); the combined second-floor areas of Milstein-Sibley-Rand are far greater than what is allowed. Fire barriers can be provided that 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 V-B). Where mixed occupancies are present in a single building, building codes provide the option of calculating the sum of the ratio of proposed to allowable floor areas for each separated occupancy (where those occupancies are separated by a fire barrier) in which case the sum of such ratios is required to be no greater than 1.0. However, the Ithaca Code Enforcement Officer has classified Milstein as both a Group B and a Group A-3 building (this was done so that any future changes from its actual Group B use to a future, hypothetical, A-3 occupancy would be permitted, in apparent violation of the Code).3 Since the occupancy group in both Milstein and East Sibley Hall is A-3, a fire barrier separating those two identical occupancy groups has no effect on the floor area calculations. Even if Milstein's second floor had been properly identified as a Group B occupancy, the area calculation for the "separated uses" still comes up short: the sum of proposed areas divided by maximum possible allowable areas for Milstein, Sibley, and Rand Halls is approximately 25,000/33,750 + 7,600/22,500 + 9,000/33,750 = 0.74 + 0.34 + 0.27 = 1.35, which is far greater than 1.0 and therefore noncompliant.4
There is only one possible strategy5 to rescue Milstein Hall's formal design concept from this apparently fatal flaw: it must be separated from the limiting wood-frame construction type of Sibley Hall by a continuous, vertical fire-resistive element known as a fire wall. Again, there is nothing particularly unusual about using fire walls to, in effect, divide a single building (from a fire code standpoint) into two 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 a fire wall were proposed, Sibley Hall would be permitted to remain as a nonconforming building, and Milstein Hall could be built as an independent, sprinklered, Type II-B noncombustible structure meeting all requirements for floor area and number of stories.
The problem is that a fire wall is extremely difficult to envision in this particular context. Section 705 in the 2002 New York State Building Code makes the reasons for this clear:
Ironically, if a fire wall had been built as envisioned above (i.e., as a stepped building), but with East Sibley's Mansard-type walls entirely rebuilt as 2-hour rated construction instead of the required 1-hour fire rated construction, the fire wall itself would no longer be required. This is because East Sibley would in that case no longer be a Type V-B (wood-frame) building. With a minimum of 2-hour fire rated construction on its exterior walls (already provided by its masonry shell below the third floor), it would qualify as Type III-B construction, which would permit enough allowable floor area to link East Sibley and Milstein's second floor for either Group A-3 or Group B occupancy without any walls or barriers between the two buildings (see Table 1). Of course, it would still be necessary to exclude the additional floor area of Rand Hall by building a fire wall between Milstein and Rand—so the problems with this approach do not entirely disappear, even if Sibley's construction type is upgraded.
This requirement for fire separation should have stopped the design for Milstein Hall in its tracks. In fact, it is not clear why the scheme was developed, unless it was assumed that one could overcome any obstacle if enough money was thrown at the problem.
As it turned out, there appeared to be an unexpected and relatively simple way out based on Appendix K in the 2002 Building Code of NYS—but this apparent loophole was about to expire with the adoption of the 2007 Building Code of NYS. Rather than acknowledging that the proposal was seriously flawed from a fire safety perspective, and would be nonconforming with the soon-to-be-adopted 2007 New York State Building Code even before construction started, the architects rushed an incomplete and noncompliant set of drawings and specifications for Milstein Hall to the Ithaca Building Department in order to obtain a building permit based on the 2002 Code containing Appendix K. 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.
Appendix K (in the 2002 Building Code of NYS) allows additions to existing buildings to exceed the floor areas ordinarily constrained by Chapter 5 (Table 503, etc.) as long as a fire barrier is provided. The exact language in Section K902.2 is as follows: "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."
The use of fire barriers to increase the area of a building is specified in Chapter 3 of the 2002 Code: two options are relevant here (both described in Section 302.3 Mixed Occupancies). In the first case for nonseparated uses, the various occupancies of the building are not separated by a fire barrier, and the entire building is governed by the height and area limitations corresponding to the most restrictive type of construction—in this case, Construction Type V-B—and the most restrictive type of occupancy—in this case, Group A-3. Thus, without using fire barriers as permitted under Appendix K, the building would be noncompliant, as it would exceed the area limits specified in Table 503 of the Code.
In the second case for separated uses, fire barriers can be used to separate the various occupancies, and the building area can be increased 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" (Section 302.3.3, 2002 NYS Code). Thus, with fire barriers used per Appendix K, the total area could be increased if, and only if, the occupancy group on either side of the fire barrier were less restrictive than Group A-3. But because both sides of the fire barrier are being designed for A-3 occupancies, the sum of the ratios of floor area divided by allowable area exceeds the limit specified in Section 302.3.3, and the building remains noncompliant. In fact, as demonstrated above, even if one side of the fire barrier were occupied by Group B, with the other side occupied by Group A-3, the sum of the ratio of actual to allowable areas would still exceed the limits of Section 302.3. With Type V-B construction, the combined floor areas are just too big.
The error made by the building's architects, sanctioned by the Ithaca Building Department, is to assume that each fire area created by the fire barrier between Milstein Hall and E. Sibley Hall 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. Otherwise, there is only a single construction type for the entire building, and the governing construction type is the one that is most restrictive with respect to height and area limitations. This is confirmed by the Commentary to the International Building Code, which explains unambiguously how construction type is determined for uses separated by fire barriers: "Part A: Determine the minimum type of construction required based on the height of each occupancy relative to the grade plane… This needs to be evaluated for both height in feet and stories above grade plane. Part B: Determine the minimum type of construction based on a weighted average of areas occupied by the various occupancies…"6 This point is clear and should be emphasized: All of the various occupancies separated by fire barriers require a single "minimum type of construction based on a weighted average of areas occupied by the various occupancies…"
There is nothing in Appendix K that provides any other 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 Code7 and the Nationally Applicable Recommended Rehabilitation Provisions (NARRP)8 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 Building Code of NYS, including all subsequent New York State Building Codes (i.e., 2007 and 2010 versions), 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 the limits of Chapter 5 (or its equivalent). 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 Building Code of NYS—contain not a single word of text describing or explaining this unique and peculiar section of Appendix K in the 2002 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.9
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 Chapters 3 and 5 (or equivalent), 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 permitted under Chapter 5 (or equivalent), it is likely that the language in Appendix K was included in error. For example, the two codes that served as a model 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." 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."10 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 Chapter 5. It should also be mentioned that Milstein Hall, as designed, would not have been permitted under either the 2007 or 2010 NYS Building Codes, both of which contain 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 Halls should be regulated when a fire barrier is provided, except by implicit reference to other applicable sections of the Code, the entire premise of combining these three buildings in a way that exceeds the allowances of Table 503 and Section 302.3.3 of the 2002 Building Code of NYS is problematic. The building's architects claim 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. As discussed earlier, every other edition of the Building Code of NYS (both early versions used before the IBC; and versions adopted in 2007 and 2010) as well as the two "model codes" that were used as a basis for 2002 NYS Appendix K (i.e., the New Jersey Rehab Code and NARRP) require a fire wall—not a fire barrier—in order to increase building area beyond that permitted in Chapter 5 of the Code. The code consultant for a later proposed occupancy change has a different justification for exceeding the floor areas allowed in Chapter 5: he claims that the combined Milstein-Sibley-Rand Hall is actually a single building, but with multiple construction types separated by fire barriers.11 However, this interpretation of the Code cannot be sustained: a single building can have only a single construction type governed by the most restrictive construction type in the combined building.
Even if one accepts the questionable premise that Milstein Hall can be designed as if it were a separate building with its own construction type, the lack of adequate fire separation distance between Milstein and Sibley Halls makes the combustible wood-framed third-floor wall of Sibley Hall noncompliant (Figure 2).
The 2002 Building Code of NYS (specifically, Section 704.10), under which Milstein Hall was permitted, 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." All of the window openings in the third floor of E. 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 do Sibley's third-floor windows require opening protectives, but the entire exterior wall on the third floor of Sibley (facing Milstein Hall) needs to be reconstructed with a 1-hour fire-resistance rating. Footnote "f" in Table 601 (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 requires a 1-hour fire-resistance rating for Occupancy Groups A or B if the fire separation distance is less than 5 feet. The fire separation distance between Sibley and Milstein Halls is 0 feet (they are physically connected).
If the fire barrier 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 2], such wall shall terminate at a point not less than 30 inches above the lower roof level, provided the exterior wall for a height of 15 feet 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." (Section 705.6.1 Stepped buildings, 2002 Building Code of NYS).
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 with multiple construction types. Not only does this violate basic building code principles (since a single building can have only one construction type; and only a fire wall can create two separate buildings each with their own construction type), but there is absolutely nothing in Appendix K, or anywhere else in the 2002 Building Code of New York State, 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 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. Under these circumstances, it seems to me that any interpretation of Appendix K should, at a minimum, make its assumptions explicit, and then act consistently according to those assumptions. Allowing a fire barrier to create two 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. Furthermore, such a strategy represents an inconsistent interpretation of Appendix K, and creates an unsafe building.<< previous | next >>
1 Based on tabular data in Table 503 (Allowable Height and Building Areas), 2002 New York State Building Code, and area modifications in Section 506. Values include area increases based on automatic sprinklers and frontage, and assume the maximum possible frontage allowance of 75%. The actual frontage allowance for this particular site may be somewhat less, depending on the assumptions used.
2 These calculations are based on the 2002 New York State Building Code under which Milstein Hall was permitted. The maximum area calculation for any floor, given Type V-B construction, A-3 occupancy, automatic sprinklers, and the maximum permitted area increase for what is called "frontage" (basically, a bonus for being far enough away from any adjacent structures) is as follows: Aa = At + [AtIf / 100] + [AtIs / 100] where Aa is the allowable area per floor, At is the tabular area from Table 503—in this case, 6,000 square feet—If is a frontage factor, the maximum possible value being 75%, and Is is a sprinkler factor which equals 200% for multi-story buildings. It can be seen that Aa = 6,000 + [6000 x 75 / 100] +[6000 x 200 / 100] = 22,500 square feet. This result is shown in Table 1.
3 "The reasons for designating the second-floor Milstein Hall spaces as group A-3 instead of group B are clear: by doing so (in apparent violation of the Code), future alterations within the A-3 occupancy group would be permitted. In other words, in order to maintain the illusion of flexibility, Milstein Hall's spaces must be improperly classified according to use." Jonathan Ochshorn, "Thoughts on Milstein Hall," Feb. 11, 2009, online here. The arguments for designating occupancies accurately (rather than anticipating what future hypothetical occupancies might be) can be found in my blog posts from January, 2009 here, here, and here (all web sites accessed July 20, 2012).
4 These numbers are taken from Figure 1 (proposed floor areas) and Table 1 (allowable floor areas for type V-B construction).
5 There are actually other strategies, for example, rebuilding portions of East Sibley Hall to change its construction type from V-B to a less restrictive construction type such as III-B. This would involve rebuilding the sloped walls of the third floor with fire-rated construction, replacing the combustible wood-frame load-bearing walls at this level. It would also require examination of the wall between East Sibley Hall and the so-called Sibley dome at the center of the building: this wall would need to be upgraded to fire wall status if it isn't already.
6 International Code Council [ICC], International Building Code: Code and Commentary, 2009, Section 508.4.
7 The New Jersey Rehab Code is found in: Title 5. Community Affairs Chapter 23. Uniform Construction Code Subchapter 6. Rehabilitation Subcode, as published in the New Jersey Register, Vol 29, No.16, Aug. 18, 1997, online here (search under New Jersey Register, enter Rehabilitation Subcode with dates bracketed from 1/1/1997 to 12/30/1997).
8 NAHB Research Center, Inc., et. al., Nationally Applicable Recommended Rehabilitation Provisions (NARRP), prepared for the U.S. Department of Housing and Urban Development, Office of Policy Development and Research, May, 1997, online here (PDF accessed July 20, 2012).
9 Conclusions about the difficulty of tracing the origin and rationale for the "fire barrier" vs. "fire wall" anomaly in Appendix K is based on my own research at the New York State Department of State Division of Code Enforcement and Administration, 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).
10 See Nationally Applicable Recommended Rehabilitation Provisions, op. cit., and the New Jersey Rehab Code, op. cit..
11 Thomas D. Hoard, Codes Analyst for HOLT Architects, P.C. in a letter dated Sept. 6, 2011 to Peter Turner, Assistant Dean for Administration, College of Architecture, Art and Planning, Cornell University, copied to Mike Niechwiadowicz, City of Ithaca Building Department, and Graham Gillespie, HOLT Architects. Online here (PDF accessed July 20, 2012).
First posted 25 July 2012. Last updated: 25 July 2012