A building code alternative solution needs a defensible comparison with the applicable acceptable solution. It should explain the departure, the required level of performance and the evidence supporting the proposed approach.
An alternative solution is a compliance route
Under the BC code framework, an alternative solution must achieve at least the minimum performance required by the relevant Division B acceptable solutions in the areas defined by their attributed objectives and functional statements. This establishes the performance benchmark for the engineering assessment.
The governing edition, applicable provisions and submission process define the basis of the analysis. Previous projects may provide relevant evidence; acceptance remains specific to the proposed building and its conditions.
Design constraints and the proposed solution
Describe the proposed design and identify which aspect differs from the acceptable solution. Separate essential project constraints from preferences. This helps the team compare an alternative solution with a conventional design revision and choose a proportionate approach.
Noven’s 30 Norwood Road project in Toronto included an alternative solution for a site-specific single-stair exiting arrangement. Such assessments identify the relevant performance requirements and the evidence supporting the proposed design.
Technical documentation
- State the project facts, assumptions and limits of the assessment.
- Identify the acceptable solutions being replaced and their attributed objectives and functional statements.
- Describe the proposed measures and the comparison method.
- Provide relevant calculations, test evidence, modelling or other substantiation.
- Explain sensitivities, uncertainty and conditions that could invalidate the conclusion.
- Identify drawing, construction, testing and operational commitments.
Design and construction commitments
An accepted report needs to become coordinated project information. Put required features on the drawings and in specifications, identify field-review responsibilities and establish how ongoing obligations will be communicated to the owner. If the solution relies on a particular operating arrangement, the handover package should make that limitation visible.
Track revisions. A change in materials, occupancy, geometry or system performance may affect the accepted basis. The team should determine whether a revised assessment and further authority review are needed before proceeding with the changed condition.
Does every alternative solution need computer modelling?
No single analysis method suits every problem. The evidence should address the actual departure and demonstrate the relevant performance. The method is selected according to the performance comparison and available evidence. Where modelling is justified, its assumptions and limitations must be part of the submission.
Noven’s services
For related project support, see our Building Code Alternative Solutions. Request a proposal for your project.
Related Insights
- Performance-Based Fire Design: What Makes a Model Useful?
- Third-Party Code Review: Scope, Independence and Clear Findings
Technical references
- BC: Guide to Letters of Assurance, BCBC 2024 and VBBL 2025
- BC Building Code 2024: application and updates
References reviewed October 23, 2026. Project requirements depend on the applicable code edition, jurisdiction and scope of work.