Four fire barrier continuity comments, two shaft enclosure rating comments, and three opening protective comments came back on a six-story Denver project. None had appeared earlier because compartmentation had not been checked before permit submission. The pattern is familiar: separate design decisions become a code problem only when someone finally reviews them together.
Compartmentation errors often arrive late because the relevant evidence is spread across architectural plans, structural framing, mechanical layouts, wall types, and schedules. By permit review, those pieces are detailed enough to expose conflicts, but late enough that correcting one item can affect several disciplines. The issue is not simply that a team missed a note. The timing of the first joined-up check leaves little room to change the design cleanly.
What the Code Requires and Where Errors Concentrate
IBC 707 governs fire barriers and requires continuity from the floor-ceiling assembly to the floor or roof above. When both assemblies are rated, the barrier can continue to a rating-matching assembly above. A wall that stops at the suspended ceiling plane does not satisfy that path. It leaves a gap between the barrier and the floor deck above, which defeats the compartmentation the rated wall was meant to provide. That condition can be easy to miss when plans are reviewed one sheet or ceiling layer at a time.
IBC 713 governs shaft enclosures, with the required rating tied to the number of stories connected: one hour for a shaft connecting fewer than four stories, and two hours for one connecting four or more. A repeated error in our beta involves a mechanical shaft in Type III-A construction that is given a one-hour assembly because it matches the standard wall specification. That construction type does not change the IBC 713 threshold. If the shaft spans four or more stories, the enclosure requires two hours.
Penetrations and Opening Protectives
IBC 714 addresses penetrations through fire-resistance-rated assemblies. Every penetration through a fire barrier, fire partition, or fire wall must be protected by a listed and tested through-penetration firestop system, or by another means specified by the code. The design may show the rated assembly correctly and still remain incomplete if services pass through it without the required protection. Those details usually depend on information that is developed later than the initial compartment layout.
IBC 716 governs opening protectives. A two-hour fire barrier requires a one-and-a-half-hour rated door assembly. A one-hour fire barrier requires a three-quarter-hour or one-hour rated door assembly, depending on the opening type. The wall rating and the door rating therefore cannot be checked as unrelated schedule entries. The opening, its location in the barrier, and the applicable assembly rating have to agree. When those relationships are resolved late, a correction can reach both the drawings and the door schedule.
Why These Get Caught Late
Compartmentation is a multi-sheet coordination problem. The architectural plan may establish a barrier, the reflected ceiling plan may show where the ceiling sits, structural drawings may define the floor or roof assembly, and mechanical drawings may establish how many stories a shaft serves. Openings and penetrations add another layer of coordination. Each view can look reasonable on its own while the combined condition fails the code requirement. That is why a late review can produce several related comments from decisions made at different points in the set.
For many teams, the first comprehensive compartmentation check is plan review itself. By then, the permit set is complete enough to reveal continuity gaps, shaft rating mismatches, and opening issues, but the design is no longer at its easiest point of change.
This is a timing problem, not merely a documentation problem. The drawings still need the detailed information required for a complete IBC 707, 713, 714, and 716 review. But a firm also needs a checkpoint during design development, or a tool that can test the higher-impact relationships before the permit set is assembled.
What a Mid-SD Check Can Catch
At schematic design, Kestrel Labs can check the proposed locations of required fire barriers, the number of stories served by proposed shafts, and whether proposed floor-to-floor openings require shaft enclosures. Those checks can expose a shaft rating issue before the surrounding design hardens. They cannot confirm penetration firestop specifications or door schedule ratings at that stage, because the required information does not yet exist in the model.
Consider the six-story mixed-use project in Denver's Cap Hill neighborhood. Its permit-set review produced four fire barrier continuity comments, two shaft enclosure rating comments, and three opening protective comments. If the team had mapped its mechanical shafts against IBC 713 at the end of schematic design, the rating requirements would have been visible before structural drawings were issued. The shaft walls could have been specified as two-hour assemblies from the start, and the structural engineer would have known the assembly requirements while designing the shaft framing. The four shaft-related plan check corrections would not have appeared.
The Trade-off Worth Naming
An early check has a defined limit. We are not saying a complete compartmentation analysis is achievable at early design stages. A full IBC 707, 713, 714, and 716 compliance check requires near-complete drawings. We are saying schematic design can support a partial check of conditions with the highest correction rate and highest cost to fix late: shaft enclosure ratings based on proposed shaft configurations, fire barrier continuity at floor-ceiling assemblies, and major opening locations at fire barriers. That check does not eliminate corrections. It reduces the most expensive subset.
Firms that build compartmentation into their SD-to-DD checkpoint process report fewer fire and life safety corrections during the permit cycle, not zero corrections. The remaining items tend to involve penetration details and opening protective specifications that depend on late-stage drawing completion. Those are generally lower-cost documentation responses rather than design changes. In practice, the checkpoint moves the largest coordination risks earlier while the final set still carries the detailed firestop and opening information.
