[updated below Oct. 13, 2011 and March 9, 2012] Appendix K of the 2002 New York State Building Code made significant changes to the model 2000 International Building Code (IBC) upon which the New York State Code was based. It allowed a building addition to “increase the area of an existing buiding beyond that permitted under the applicable provisions of Chapter 5 of the Building Code for new buildings” as long as a fire barrier was provided.

Normally, a fire wall — not a fire barrier — would be required in such cases, but NYS legislators wanted to make it easier and less expensive (and therefore less safe) to build additions to existing structures. Whereas it is absolutely clear what a fire wall is, and where it must be placed in relation to the parts of a building it is separating, this hastily contrived NYS appendix doesn’t bother to specify exactly where its alternative fire barrier must be provided.

This wouldn’t be much of a problem if the addition were the same height as the existing building. However, Milstein Hall at Cornell University (OMA – Rem Koolhaas architects) is a two-story building addition connected to Sibley Hall, which is a three-story building (see building section below, adapted from Cornell’s Milstein Hall web site). The architects for Milstein initially had called for a fire barrier between the two buildings, but only on the second-floor where they literally connect. It was only later, when this assumption was challenged, that they added fire barrier protection at all levels where the two buildings come into contact (i.e., at the basement and first-floor levels as well) — see update below. Left with no protection at all is the thrid-floor exterior wall of E. Sibley Hall overlooking Milstein’s green roof.

Sibley and Milstein Halls (adapted from Cornell's Milstein Hall web site)

This is a problem for two reasons. First, the window openings on the third floor of Sibley have no fire protection. Second, the wooden load-bearing exterior wall of Sibley’s third floor has no fire-resistance rating. None of this was a problem when Sibley was a non-conforming, grandfathered, free-standing building. It becomes a problem with the construction of Milstein Hall.

The 2002 New York State Code (specifically, Section 704.10), under which Milstein 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’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), based on the most generous assumption that one can make, i.e., that they are effectively two separate buildings. Actually, Appendix K only allows them to be considered as separate buildings from the standpoint of “area” (K902.2). However, if they were considered as a single building — as would be required under the current building code (i.e., without a fire wall) — then all of this discussion would be moot since Milstein Hall would be clearly noncompliant. Either way one looks at it — as a single building or as two separated buildings — the current situation appears to be noncompliant.

[Update: Oct. 13, 2011] As it turns out, the nonconforming fire barrier placed between Sibley and Milstein Hall — to satisfy the ambiguous requirements of Appendix K from the 2002 Building Code of NYS — is not only nonconforming but also noncompliant. The width of fire-rated openings in such a fire barrier cannot exceed 25 percent of the length of the fire barrier wall. In the image below, the aggregate width of openings is shown graphically in relation to the total length of the fire barrier wall. It can be seen that the opening width greatly exceeds the 25 percent limit:

[Update: March 9, 2012] A noncompliant solution to the fire barrier problem was proposed and recently installed. At great expense. And completely useless. See my analysis here.

There are plans to move Cornell’s Fine Arts Library from Sibley Hall, where it has existed as a nonconforming (”grandfathered”) occupancy for quite a few years, to Rand Hall, which is now connected to Sibley Hall through newly-constructed Milstein Hall. Because the addition of Milstein Hall was, and is, nonconforming with respect to the current New York State Building Code, it may not be possible to put a library occupancy in Rand Hall. I made a similar argument about placing so-called Group A occupancies in Sibley Hall. This same explanation applies to Group A occupancies in Rand.

A future change to an A-3 (library or lecture hall) occupancy in Rand Hall should not be permitted, because such a change would be replacing an existing occupancy with one of a higher hazard. The relevant code language is as follows: Section 812.4.2.1 of the Existing Building Code of New York State says: “When a change of occupancy group is made to a higher hazard category as shown in Table 812.4.2, heights and areas of buildings and structures shall comply with the requirements of Chapter 5 of the Building Code of New York State for the new occupancy group.” Table 812.4.2 classifies group A-3 spaces as having a “relative hazard” of 2 (with 1 being the highest hazard), and group B spaces (the current occupation of Rand’s 2nd and 3rd floor, per email from City of Ithaca Senior Code Inspector John Shipe) as having a relative hazard of 4 (lowest hazard). Therefore, it is clear that a change from group B to group A-3 constitutes an alteration to a higher hazard occupancy.

With such a change, the building — which under the current building code is defined as Rand-Sibley-Milstein — must conform to the requirements of Chapter 5 of the current Building Code of New York State. What are those requirements? Chapter 5 regulates the allowable heights and areas of buildings, based on construction type and occupancy. Since the fire barrier separating Milstein and Sibley Halls is nonconforming with respect to the current code, it [i.e., the fire barrier — clarification added 10/2/11] cannot be invoked to consider Rand-Milstein Hall as a separate building, as would be the case with a fire wall. Therefore, Rand-Sibley-Milstein must be treated as a single building under the current code, and the height/area limits are as follows: the maximum height is 60 feet; the maximum number of stories is two; and the maximum area on a single floor is at most 22,500 sq.ft. The combined second-floor area for Rand-Sibley-Milstein greatly exceeds this limit of 22,500 sq.ft., and the number of stories in Rand-Sibley-Milstein similarly exceeds the Code limit of two. Based on either of these criteria (floor area or number of stories), any alteration to a higher hazard occupancy should not be permitted, as the requirements of Chapter 5 would not be met, and cannot be met.

In other words, putting the library on the 3rd floor of Rand would violate the Code limit of two stories; putting the library on the 2nd floor of Rand would violate the floor area limit.

[Update: Oct. 13, 2011] The move of the Fine Arts Library into Rand Hall has taken place this past week, in spite of the objections I have raised. Here are a few additional points, for the record:

1. On Oct. 7, 2011, I sent an email to the Milstein Hall project director which included this clarification:

“I didn’t mention this to GW at today’s meeting, but my notes that I gave him on Code issues (attached) state that: ‘the exception [to Section 912.5.1 of the Existing Building Code of NYS] only permits a fire barrier, if used in lieu of a fire wall, to meet area limitations for the new occupancy — NOT height limitations. Only a fire wall can meet both height and area limitations for the new occupancy.’ In other words, the library move to the 3rd floor of Rand will not be in compliance even if the fire barrier between Rand and Milstein is upgraded. Only a fire wall would make such a move compliant. On the other hand, an upgraded fire barrier would appear to allow such a move to the second floor of Rand Hall. In either case, the current fire barrier is noncompliant.”

2. The contention that a library (A-3 occupancy) constitutes a higher hazard occupancy compared to the current use in the Rand Hall space is the underlying reason why such a move is noncompliant. The Code is unambiguous about the occupancy of libraries as A-3. Design studios are not specifically mentioned in the Code; rather, they fall under the Group B definition for educational occupancies above the 12th grade. If there was any doubt about the legitimacy of this classification, the Ithaca Building Department files for Rand Hall contain numerous documents, all confirming that the Group B designation was actually used for the studio spaces in Rand Hall. Older documents in the file show a C5.5 designation; this was the old New York State Code subcategory for Educational occupancies within the “Commercial” category — exactly equivalent to the modern Group B designation. See this document copied from the Rand Hall Building Department file.

3. Even if a fire wall were built between Rand and Milstein Halls, it would still be necessary to upgrade the two egress stairs in Rand Hall, which are noncompliant once the occupancy on the third floor changes to a higher hazard. For details, see my email to the Milstein Hall project director.

Walking across Cornell’s campus the other day, I was struck by the similarity between Uris Hall, designed by Gordon Bunshaft (Skidmore, Owings & Merrill) in the 1970s, and Paul Milstein Hall, designed by Rem Koolhaas (Office for Metropolitan Architecture – OMA) in the 2000s.

Facade of Uris Hall (S.O.M.) applied to the rendering of Milstein Hall (O.M.A.).

Both buildings consist of  large, essentially square, floor plates supported by rigid frames (vierendeel trusses) lifted off the ground and cantilevered in dramatic fashion from their points of support. Both buildings also hover over large, below-grade, auditoriums: in the case of Uris Hall, the auditorium sits politely under the podium; in Milstein Hall, the auditorium rides a reinforced concrete dome that seems to burst through the ground plane. Both buildings mediate their cantilevered steel superstructures and highly-articulated bases with a glass wrapper designed to enclose space and provide an entry at grade without compromising the visual articulation of superstructure and base.

Official rendering of Milstein Hall.