Code analysis project

For the final project Kostyshyn takes the class back to a building they first saw in Building Technology: the four-storey mixed-use building on Portage Avenue, now finished and occupied. It has a concrete ground floor with two shops, a residential lobby, a bike room and a garbage room, and three floors of wood-frame apartments above, forty-two homes in all. Kostyshyn has obtained permission from the owner and the architect to use the permit drawings, with the code analysis sheet removed. The students' task is to write it again from scratch, working in pairs, and then to compare their analysis with the architect's. 'This is the most common drawing an architect produces that nobody outside the profession ever sees,' she says. 'If you can do this one well, you can walk into any office in the country and be useful on the first day.'

What a code analysis contains

A code analysis is a summary of how a building complies with the codes that apply to it, usually set out on the first sheet of the permit drawings with supporting plans that show fire separations, exits and accessible routes. It tells the plans examiner, in a few minutes, what the building is, what rules govern it and how it meets them. Kostyshyn's template has twelve sections, one for each lesson of the course.

• Project information: address, legal description, owner, architect, engineers, scope of work and description of the building.
• Codes and standards: the codes in force with their editions and amendments, the referenced standards relied on, and any alternative solutions proposed.
• Classification: each major occupancy and its location, and how mixed occupancies are treated.
• Building size: building area and height as the code defines them, the streets faced or the frontage, and the article used.
• Construction: the construction type, the fire-resistance ratings required for floors, roofs, walls and supporting elements, and the assemblies that provide them.
• Fire separations: separations between occupancies, suites, corridors, exits, shafts and service rooms, with their ratings and the ratings of their closures.
• Spatial separation: each exposing face with its distance, area of openings and required wall construction.
• Egress: occupant loads, number and width of exits, travel distances, dead ends, separation of exits and accessible egress.
• Fire protection systems: sprinklers, standpipes, fire alarm, emergency lighting and firefighter access.
• Accessibility: accessible entrances, paths, washrooms, units and parking, and the standards applied.
• Energy: the energy code, climate zone, compliance path and key values.
• Zoning summary: a short cross-reference to the zoning approval, so the examiner sees the whole picture.

Classifying and sizing the building

The building is four storeys high with a building area of about 1,008 m², so it is a Part 3 building. It contains two major occupancies: Group E, mercantile, for the shops on the first storey, and Group C, residential, for the lobby, the apartments and their supporting rooms. The garbage and bike rooms serve the residential occupancy. Wren and Joon-ho first check whether the shops could be treated as a minor part of the residential occupancy, but at more than half of the first storey they are clearly a major occupancy, so the building is a mixed occupancy. For building size and construction the more restrictive requirements apply, so they check both the study article for Group C, up to four storeys, sprinklered, and the one for Group E, up to four storeys, sprinklered. Both permit combustible construction and allow 1,800 m² at four storeys, with one-hour floors.

Joon-ho notices something the architect may not have needed to do. The study articles would have allowed the whole building, shops included, in combustible construction. The concrete first storey was not required by the building size rules. Kostyshyn confirms it and explains why the architect chose concrete anyway: the shops need long spans and flexible plans for future tenants, the street-level walls must resist damage and moisture, the concrete slab separates the noise of the shops from the homes above, and the slab provides the rated separation between the two occupancies with ease. 'Not every decision in a code analysis comes from the code,' she says. 'But every decision must be checked against it.'

Separations, exits and systems

The fire separations follow from the classification. The first-floor slab separates the mercantile occupancy from the residential occupancy above; the team records a two-hour concrete slab, which meets or exceeds the separation the code's table requires between these major occupancies. Each shop is separated from the lobby and service rooms by a fire separation. Above, the floors are one-hour fire separations, each apartment is separated from its neighbours and the corridor, the two exit stairs are enclosed by one-hour fire separations continuous from the roof to the ground floor, where each discharges directly outside, and the elevator shaft and the garbage chute are enclosed by rated shafts. The two side walls stand on the lot lines, so their limiting distance is zero and they may have no unprotected openings; they must be built as rated walls with noncombustible cladding. The street face looks across Portage Avenue, whose centre line is far enough away that any amount of glass is permitted.

The students then work through egress, fire protection, accessibility and energy, using the methods of the earlier lessons. The script below gathers the key numbers and prints the core of the code analysis table.

# Code analysis summary: four-level mixed-use building (NBC as adopted in Manitoba)
fp = 28.0 * 36.0                         # building area (m2)
levels = 4
shop_area, lobby_area = 600.0, 180.0
bedrooms_per_floor = 20
loads = {"level 1 shops": shop_area / 3.7, "level 1 lobby and services": lobby_area / 9.3}
for lv in (2, 3, 4):
    loads[f"level {lv} homes"] = 2 * bedrooms_per_floor
stair_need = max(v for k, v in loads.items() if "homes" in k) * 8.0     # mm, stairs serve one level at a time
rows = [
    ("Codes", "Manitoba Building Code (2020 NBC with amendments); Manitoba Energy Code for Buildings"),
    ("Part", f"Part 3 ({levels} levels, {fp:.0f} m2)"),
    ("Major occupancies", "Group E (level 1 shops); Group C (lobby and homes)"),
    ("Size", f"area {fp:.0f} m2 <= 1800 m2 at 4 levels (study article, sprinklered)"),
    ("Construction", "combustible permitted; level 1 noncombustible by choice; floors 1 h"),
    ("Separations", "E/C 2 h slab; suites and corridors rated; stairs 1 h; closures to the code table"),
    ("Occupant loads", ", ".join(f"{k} {v:.0f}" for k, v in loads.items())),
    ("Exits", f"2 stairs, 1100 mm (load needs {stair_need:.0f} mm); travel <= 45 m; dead ends <= 6 m"),
    ("Fire protection", "NFPA 13 throughout; standpipes; fire alarm to CAN/ULC-S524; FDC on the avenue"),
    ("Accessibility", "Section 3.8 and CSA B651; accessible entrances; elevator to every level"),
    ("Energy", "NECB 2020 basis, zone 7A, performance path (street face glazing above the prescriptive ratio)"),
]
for k, v in rows:
    print(f"{k:<18} {v}")

Codes              Manitoba Building Code (2020 NBC with amendments); Manitoba Energy Code for Buildings
Part               Part 3 (4 levels, 1008 m2)
Major occupancies  Group E (level 1 shops); Group C (lobby and homes)
Size               area 1008 m2 <= 1800 m2 at 4 levels (study article, sprinklered)
Construction       combustible permitted; level 1 noncombustible by choice; floors 1 h
Separations        E/C 2 h slab; suites and corridors rated; stairs 1 h; closures to the code table
Occupant loads     level 1 shops 162, level 1 lobby and services 19, level 2 homes 40, level 3 homes 40, level 4 homes 40
Exits              2 stairs, 1100 mm (load needs 320 mm); travel <= 45 m; dead ends <= 6 m
Fire protection    NFPA 13 throughout; standpipes; fire alarm to CAN/ULC-S524; FDC on the avenue
Accessibility      Section 3.8 and CSA B651; accessible entrances; elevator to every level
Energy             NECB 2020 basis, zone 7A, performance path (street face glazing above the prescriptive ratio)

The table fits on half a sheet. Wren and Joon-ho add the plans that support it: a fire separation plan for each floor, an egress plan with travel distances drawn, an accessibility plan of the ground floor and a typical floor, and a spatial separation diagram of each face. The finished analysis runs to three sheets.

Comparing with the architect

When the pairs compare their analyses with the architect's original sheet, they find that most of their conclusions match, and they learn as much from the differences. Callum and Ingrid had counted the apartments' occupant load by bedrooms, as the NBC does, and the architect had used the code's method for the jurisdiction. Wren and Joon-ho had missed the garbage chute entirely; the architect had shown it as a rated shaft with a sprinklered room at its base. Everyone had missed a small mezzanine storage room above the bike room, which the architect had shown as part of the first storey because it was under the size at which a mezzanine counts. The architect had proposed one alternative solution, for a glazed lobby wall beside the stair, and the students read the submission: two pages, with fire test data for the glazing and a short argument that it gave equivalent protection.

Kostyshyn points to the habits that made the architect's analysis easy to review. Every line had a code reference. Every number had a source. Every rated wall on the plans matched a listed assembly in the specifications. Assumptions were stated, such as the bedroom counts and the hazard classification of the shops, so that a future tenant who changed the use would know what had been assumed. And the analysis had been updated at every stage, from schematic design to the issued-for-construction set, with a revision note each time.

When the analysis changes

A code analysis is not finished when the permit is issued. Buildings change during construction and long after. A tenant wants to turn one of the shops into a restaurant, which changes it from Group E to Group A, Division 2, with a higher occupant load, more exits, a different separation from the homes above and a commercial kitchen exhaust. A later owner wants to convert the bike room into two more apartments. Each change must be checked against the code in force at the time, starting from the original analysis. The architect who wrote it clearly has made the next architect's work possible.

The students take the restaurant case as a last exercise. With tables and chairs, the larger shop of 340 m² would have an occupant load of about 358 people, more than double that of a store. It would need two exits from the shop, panic hardware, a more demanding separation from the residential floors and, in many cases, accessible washrooms for customers. Kostyshyn tells them that this is exactly the kind of question she was asked every week in the permit office, and that the answer was always found by starting from the original code analysis.

Professional judgement

Kostyshyn closes the course where she began, with the binder. She tells the students about the cases where the code had no answer: a building type nobody had imagined, a heritage building that could not meet the modern rules, a client who wanted to do more than the code asked. In each case the architect had to return to the code's purposes, its objectives and intent, and make a judgement. The National Building Code's objective-based structure, with its objectives and functional statements, is designed for exactly this, so that the designer can show how an unusual building meets the code's aims. The code is a minimum and a tool, and an architect who understands it well enough to explain it is free to design well above it.

Danielle Roy, Daniel Achterberg, Kofi Mensah and Ahmed Farouk come to the final review. Each pair presents its code analysis in ten minutes, with the code open on the table, as Kostyshyn promised in the first week. Achterberg asks every pair the same question at the end: 'Who will this building leave out?' The best answer, from Wren, is that it leaves out nobody on the ground floor, and that the next building she designs will do better on the upper floors by making every home visitable from the start.

Exercise 12: code analysis project

• Prepare a complete code analysis for the four-storey mixed-use building, with the twelve sections of the template and supporting plans.
• Compare your analysis with the original and write one page on the differences and what you learned from them.
• Prepare a revised analysis for the change of one shop to a restaurant.
• Present your analysis in ten minutes to a reviewer, as if at a pre-application meeting with the permit office.

Self-check

• Does every number in my analysis have a code reference and a source?
• Have I stated my assumptions so that a future reader can check them?
• Could an examiner understand my building from the first sheet alone?