[Reserved for Publication]

Note: This draft standard is under development and subject to change. It should not be used for reference purposes.Please read this Accessibility Standards Canada (ASC) legal notice (hereafter referred to as “ASC legal notice”) before using this draft standard. ,

2.1 General

The Canadian Accessibility Standards Development Organization (operating as “Accessibility Standards Canada”) standards are developed through a consensus-based standards development process approved by the Standards Council of Canada. This process brings together volunteers representing varied viewpoints and interests to achieve consensus and develop standards.Although Accessibility Standards Canada administers the process and establishes rules to promote fairness in achieving consensus, it does not independently test, evaluate, or verify the content of the standards. During this process, Accessibility Standards Canada makes the draft standard available for comment, review, and approval. ,

2.2 Understanding this edition of the draft standard

Revisions may have been or may eventually be developed in relation to this edition of the draft standard. It is the responsibility of the users of this document to verify if any revisions exist. ,

2.3 Disclaimer and exclusion of liability

This is a draft document for the purpose of comment, review, and approval only. This document is provided without any representations, warranties, or conditions of any kind, expressed or implied, including, without limitation, implied warranties or conditions concerning this document's fitness for a particular purpose or use, its merchantability, or its non-infringement of any third party's intellectual property rights. Accessibility Standards Canada does not warrant the accuracy, completeness, or currency of any of the information published in this document. Accessibility Standards Canada makes no representations or warranties regarding this document's compliance with any applicable statute, rule, regulation or combination thereof. Users of this document should consult applicable federal, provincial, and municipal laws and regulations. Accessibility Standards Canada does not, by the publication of its standards documents intend to urge action that is not in compliance with applicable laws, and this document may not be construed as doing so.In no event shall Accessibility Standards Canada, its contractors, agents, employees, directors, or officers, or his majesty the king in right of Canada, his employees, contractors, agents, directors, or officers be liable for any direct, indirect, or incidental damages, injury, loss, costs, or expenses, however caused, including but not limited to special or consequential damages, lost revenue, business interruption, lost or damaged data, or any other commercial or economic loss, whether based in contract, tort (including negligence), or any other theory of liability, arising out of or resulting from access to or possession or use of this document, even if accessibility standards Canada or any of them have been advised of the possibility of such damages, injury, loss, costs, or expenses.In publishing and making this document available, Accessibility Standards Canada is not undertaking to render professional or other services for or on behalf of any person or entity or to perform any duty owed by any person or entity to another person or entity. The information in this document is directed to those who have the appropriate degree of knowledge and experience to use and apply its contents, and Accessibility Standards Canada accepts no responsibility whatsoever arising in any way from any and all use of or reliance on the information contained in this document.Accessibility Standards Canada publishes voluntary standards and related documents. Accessibility Standards Canada has no power, nor does it undertake, to enforce conformance with the contents of the standards or other documents published by Accessibility Standards Canada. ,

2.4 Intellectual property and ownership

As between Accessibility Standards Canada and users of this document (whether it be printed, electronic, or alternate form), Accessibility Standards Canada is the owner, or the authorized licensee, of all copyright and moral rights contained herein. Additionally, Accessibility Standards Canada is the owner of its official mark. Without limitation, the unauthorized use, modification, copying, or disclosure of this document may violate laws that protect Accessibility Standards Canada and/or others' intellectual property and may give rise to a right in Accessibility Standards Canada and/or others to seek legal redress for such use, modification, copying, or disclosure. To the extent permitted by licence or by law, Accessibility Standards Canada reserves all intellectual property and other rights in this document. ,

2.5 Patent rights

Some elements of this Standard may be the subject of patent rights or pending patent applications. Accessibility Standards Canada shall not be held responsible for identifying any or all such patent rights. Users of this Standard are expressly informed that determination of the existence and/or validity of any such patent rights is entirely their own responsibility. ,

2.6 Licence to comments

In this ASC Legal notice, a “comment” refers to all written or orally provided information, including all suggestions, that a user provides to Accessibility Standards Canada in relation to a standard and/or a draft standard. By providing a comment to Accessibility Standards Canada in relation to a standard and/or draft standard, the commenter grants to Accessibility Standards Canada and the Government of Canada a non-exclusive, royalty-free, perpetual, worldwide, and irrevocable licence to use, translate, reproduce, disclose, distribute, publish, modify, authorize to reproduce, communicate to the public by telecommunication, record, perform, or sublicense the comment, in whole or in part and in any form or medium, for revising the standard and/or draft standard, and/or for non-commercial purposes. By providing the comment, the commenter being the sole owner of the copyright or having the authority to license the copyright on behalf of their employer, confirms their ability to confer the licence and the commenter waives all associated moral rights, including, without limitation, all rights of attribution in respect of the comment. Where the provider of the comment is not the comment's author, the provider confirms that a waiver of moral rights by the author has been made in favour of the provider or the comment's copyright owner. At the time of providing a comment, the commenter must declare and provide a citation for any and all intellectual property within the comment that is owned by a third party. ,

2.7 Authorized uses of this document

This document, in all formats including alternate formats, is being provided by Accessibility Standards Canada for informational, educational, and non-commercial use only. The users of this document are authorized to do only the following:Load this document onto a computer for the sole purpose of reviewing it.Search and browse this document.Print this document if it is in electronic format.Users shall not and shall not permit others to:Alter this document in any way or remove this ASC legal notice from the attached standard.Sell this document without authorization from Accessibility Standards Canada.Use this document to mislead any users of a product, process, or service addressed by this Standard.If you do not agree with any of the terms and conditions contained in this ASC legal notice, you must not load or use this document or make any copies of the contents hereof. Use of this document constitutes your acceptance of the terms and conditions of this ASC legal notice.

[Reserved for Publication]

[Reserved for Publication]

This Standard has been developed to guide designers and builders in creating accessible-ready modular and prefabricated (including accessible‑ready small modular and prefabricated housing). The intent is to provide guidelines specifically for modular and prefabricated housing with a flexible design framework that allows end users to select the accessibility features they need. This approach supports changing user needs over time and makes it easier for future users to adapt the home to their specific needs.This Standard recognizes the diversity of disability experiences—including physical, sensory, cognitive, psychosocial, neurodivergent, and environmental sensitivities—and recommends co-design approaches that meaningfully involve people with disabilities in the design and documentation of accessible-ready modular and prefabricated housing.The accessibility features considered in this Standard are primarily aligned with CSA/ASC B652:23. CSA/ASC B652:23 served as the principal reference for mapping accessibility requirements to an accessible-ready context. This Standard is also aligned with CAN-ASC‑2.8:2025.This Standard is intended to be applied alongside the CSA A277-16 (R2021), which addresses certification, construction, and quality control methods. Together with CAN-ASC‑2.8:2025, CSA A277-16 (R2021) and local building regulations, this Standard provides guidance for the design and construction of accessible-ready modular and prefabricated housing, including accessible-ready small modular and prefabricated housing.

This document is for the design and construction of new accessible‑ready modular and prefabricated housing (including accessible-ready small modular and prefabricated housing). This Standard focuses on areas or elements that would reduce the effort and barriers associated with retrofitting typical modular and prefabricated homes into accessible ones. These include the following:Exterior areas and clearancesParking structures and garagesInterior areas, rooms, spaces (e.g. kitchens and bathrooms) and circulationOperating controlsStairsVertical paths of travelDoorsStructural systemsEmergency egressesMechanical systemsElectrical systemsNote: This Standard may also be used as guidance for substantial renovation projects to existing modular and prefabricated housing where accessible-ready provisions are required. ,

6.1 Inclusions

This Standard applies to modular and prefabricated housing, including small modular and prefabricated housing, that are required to be accessible‑ready or that desire to be labelled as accessible‑ready.Note: For other off-site constructed or movable dwellings (e.g. tiny homes, park model homes, or manufactured homes not meeting the Clause 9.1 definition), CAN‑ASC‑2.8:2025 and CSA/ASC B652:23 should be consulted to avoid mislabelling units as “accessible-ready” where this Standard does not apply. ,

6.2 Exclusions

This Standard excludes housing that is not defined as modular and prefabricated housing as per Clause 9.1 of this Standard. Homes and dwellings that are not considered modular and prefabricated units may refer to CSA/ASC B652:23 and CAN‑ASC‑2.8:2025.Note: For other off-site constructed or movable dwellings (e.g. tiny homes, park model homes, manufactured homes not meeting the Clause 9.1 definition), CAN‑ASC‑2.8:2025 and CSA/ASC B652:23 should be consulted to avoid mislabelling units as “accessible‑ready” where this Standard does not apply. ,

6.3 Applications

This Standard specifies the technical requirements for the design and construction of new accessible-ready modular and prefabricated housing. It does not, however, address the implementation and enforcement of these requirements. The determination of the scope and applicability of the technical provisions is the responsibility of the relevant Authority Having Jurisdiction (AHJ), including bodies that regulate building officials. ,

6.4 Limits

Limitations in modular and prefabricated housing design lie in the pre‑planning that may be required for panels and module size, connections and layouts. When panel and module dimensions, connections, and placements are designed without consideration for future reconfiguration, such as widening hallways, adjusting circulation spaces, or altering room layouts, they can significantly restrict modular and prefabricated housing from being accessible-ready.Note: Manufacturer’s instructions for the proper transportation, handling, storage, installation, and connections should be followed as the primary source of guidance. This Standard is intended to supplement, not replace, these instructions. ,

6.5 Other relevant restrictions or considerations

This Standard is intended to align as much as possible with previously referenced accessibility codes, requirements and standards.The approach was developed to assist designers and builders in meeting accessibility requirements by making spaces accessible-ready for future purposes, while addressing the constraints typical of modular and prefabricated housing. Different manufacturers of modular and prefabricated housing may have different restrictions and constraints.This Standard addresses some of the most common constraints that may prevent housing from being accessible-ready. This Standard incorporates creative design solutions to guide designers in preparing modular and prefabricated housing for accessibility. ,

6.6 Terminology

In this Standard, three terms are defined as follows:Shall: Expresses a requirement, or a provision that the user is obliged to satisfy to comply with the standard.Should: Expresses a recommendation, or that which is advised but not required.May: Expresses an option, or that which is permissible within the limits of the standard.Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate explanatory or informative material.Notes to tables and figures are considered part of the table or figure and may be written as requirements.Annexes are designated normative (mandatory) or informative (non‑mandatory) to define their application.

6.6.1 Use of the term “significant”

The adjective “significant” is frequently used throughout this Standard in contexts such as significant renovations or significant damage. It is acknowledged that this descriptor is not quantitative and is perceived differently by different individuals. However, as a person in the residential construction industry reads through this Standard, a feel for what is considered significant in this Standard will become obvious. In each clause and its commentary, some additional information is provided to give a better understanding of what significant entails. The philosophy adopted in this Standard is to qualitatively assess the design of a dwelling and the work required to replace, remove, or retrofit a component (e.g. replacing a bathroom vanity) relative to the level of effort required to modify the hidden systems of the home, i.e. non-value-added modifications (e.g. structural, building envelope, mechanical, and electrical systems).

6.6.2 Examples of “significant renovations”

Examples of “significant renovations” for the purposes of this Standard include, but are not limited to:Relocation of a toilet to achieve sufficient manoeuvring space in a bathroom.Removal of a load-bearing wall, requiring structural reinforcement.Structural modification of floor joist systems in order to accommodate an elevator.Running new dedicated electrical circuits for lifts, power-assisted door operators, and any other equipment.Relocation or rerouting of mechanical services where they were not installed to accommodate relocation.

This Standard refers to the following publications and, where such reference is made, it shall be to the edition listed below: ,

7.1 Normative

The following standards are necessary for applying this Standard in certain contexts:Accessibility Standards CanadaCAN-ASC-2.8: 2025-Accessible-Ready HousingCSA Group/ Accessibility Standards CanadaCSA/ASC-B651:23-Accessible design for the built environmentCSA/ASC-B652:23-Accessible dwellingsCSA GroupCSA A277-16 (R2021)-Procedure for Certification of Prefabricated Buildings, Modules, and Panels ,

7.2 Informative

This Standard refers to the following acts, codes, and statutes, and where such reference is made, it shall be to the edition listed below.Government of CanadaAccessible Canada Act, 2019

8.1 Definitions

The following definitions shall apply in this Standard:Accessible‑ready modular or prefabricated housing, or both — a dwelling unit that is designed and built as a modular, or prefabricated home, or both and complies with CAN‑ASC‑2.8:2025.Design for accessible-ready (DAR) — a specific type of design requirement that is included in the design and documented, but not constructed, so as to inform and support future housing alterations that include accessibility features or requirements.Note 1: The rules around these design requirements are provided in the body of this Standard. The required documentation is provided as part of a separate drawing set, or the form provided in Annex A of this Standard, or both.Note 2: Housing alterations include but are not limited to remodeling, modifying, renovating, rehabilitating, reconstructing, restoring, or making changes to an existing residence.For the purpose of this Standard, the term “modular housing” will refer to all types of prefabricated and factory-built housing.Dwelling — a housekeeping unit used or intended to be used by one or more people and usually contains cooking, eating, living, sleeping, and sanitary facilities.Source: CSA/ASC B652:23Factory — a manufacturing facility that provides protection of construction materials, components, equipment, and products against adverse environmental effects during storage and fabrication.Source: CSA A277-16 (R2021)Modular housing — a type of prefabricated housing in which the building is produced as three-dimensional (volumetric), partially or fully enclosed modules manufactured off-site, transported to the site, and assembled/connected to form the completed dwelling. Volumetric modular construction is commonly described as reaching a high degree of completion in the factory before final on-site assembly.Multi-unit residential building — a structure containing multiple separate housing units for residential occupancy, or a situation where more than one housing unit is situated within the same complex or development. Source: CSA/ASC B652:23Prefabricated housing (prefab and factory-built housing) — a housing construction approach in which building elements are manufactured off-site in a factory or controlled environment, ranging from panels (e.g. walls, floors, roofs) to volumetric units, and then transported to the site for installation and assembly. This includes panelized housing and manufactured homes.Prefabricated module — an open or closed non-planar subassembly constructed in a factory and designed for use as an integral part of a building.Source: CSA A277-16 (R2021)Note: Roof assemblies with trusses, sheathing and roofing, bathrooms, and kitchens are examples of prefabricated modules. ,

8.2 Abbreviations

The following abbreviations shall apply in this Standard:DARDesign for Accessible-ReadyHVACHeating, ventilation, and air conditioning

This Standard is intended to be applied to all modular and prefabricated housing, including small modular and prefabricated housing.Where accessible-ready modular and prefabricated housing forms part of a multi-unit residential building (e.g. apartment or condominium), common exterior and interior spaces shall comply with the requirements of CSA/ASC B651:23.All dwelling units within a multi-unit residential building that uses modular or prefabricated construction should be designed and constructed as accessible-ready units, in accordance with this Standard and CAN‑ASC‑2.8:2025, in addition to any units that are fully accessible under CSA/ASC B652:23. ,

9.1 Design for accessible-ready

Where design for accessible-ready (DAR) is specified in this Standard, it refers to design and documentation that shall be submitted with the permit application. This documentation can then be made available to the original owners as well as subsequent owners.The documentation shall indicate where and how the home can be adapted to provide a specified accessibility feature.Note: It is expected that the building permit package will include a separate accessibility drawing and or form or both to be completed, outlining the design for accessible-ready as specified in this Standard (see Annex A of this Standard). ,

9.2 Distribution of accessible-ready housing

All modular and prefabricated units that do not comply with CSA/ASC B652:23 should meet the requirements of this Standard.

All non-common interior and exterior areas and accessible-ready features of modular and prefabricated housing shall comply with CAN‑ASC‑2.8:2025, where housing is designed and constructed as accessible-ready modular housing.These requirements apply to, but are not limited to, the following:Exterior areas and clearancesParking structures and garagesInterior areas, rooms, spaces (e.g. kitchens and bathrooms) and circulationOperating controlsStairsVertical paths of travelDoorsEmergency egressesNote: The main differences between site-built and modular construction lie in their methods, and in some instances, the material used. The installation of interior and exterior features, including accessible-ready elements, generally remains the same.Therefore, the same requirements and installation methods used in CAN‑ASC‑2.8:2025 can be used for internal spaces.This Standard focuses on areas where constraints of modular construction may lead to unintended consequences for accessible-ready designs.

The designer or manufacturer of a modular and prefabricated housing, or both shall:provide the DAR documents (DAR form or DAR drawings, or both) as required by CAN‑ASC‑2.8:2025 as a part of the permit submission, and include this documentation in the owner’s manual;include the DAR documents (DAR form or DAR drawings, or both) as required by CAN‑ASC‑2.8:2025 within the documentation maintained under the CSA A277-16 (R2021); andinclude a note on the label affixed to the house, as required by CSA A277-16 (R2021), stating that the house is designed as “Accessible‑Ready” in accordance with this Standard or CAN‑ASC‑2.8:2025 or both. Additional information indicating where the DAR documents are located shall also be provided on that label.Note: Modular construction has the advantage of pre-planning and design.

12.1 Load-bearing walls

Where an interior load-bearing structure is required, it shall:use a post and beam system (i.e. columns and beams) instead of an interior load-bearing wall;except as provided in item c) of this Clause, have a clear span between columns:of at least 4,200 mm; orextend the full length of the wall section being replaced; andNote: The minimum clear span requirement between columns specified in item b) of this Clause may be reduced to 3,000 mm. The reduced clear span of 3,000 mm, is based on a typical 3‑ply 38 mm × 235 mm beam with a supported length of 2,400 mm.if all rooms and spaces adjacent to the load-bearing structure maintain compliance with the spatial and circulation requirements of CSA/ASC B652:23, including:clause 4.4.1 Accessible paths of travel;clause 4.4.2 Clear floor spaces;clause 4.4.3 Knee and toe clearances;clause 4.5.2 Floor area;clause 5.7.2 Manoeuvring area at doors;clause 5.7.3 Two doors in series;clause 5.8.1 Accessible path of travel—Horizontal;clause 5.9 Bathroom(s);clause 5.10 Kitchens;clause 5.11 Bedrooms;clause 5.12 Laundry;clause 5.14 Home automation; andclause 5.15 Service rooms and spaces;Note 1: Modular construction may require, for fabrication, transportation, or installation purposes, the construction of load-bearing walls, doubled walls, or other interior load-bearing structures.Note 2: Minimizing the use of load-bearing interior walls can make it more straightforward to reconfigure interior spaces without major structural changes.Note 3: Avoid installing mechanical, electrical, plumbing, and HVAC systems within interior walls to facilitate removal or modification for creating accessible paths of travel, without significant changes. ,

12.2 Service chases

12.2.1 Vertical service chases

To facilitate future changes to the space, services (HVAC, plumbing, electrical, etc.) shall:be grouped together by floor generally in a maximum of two groups, unless design circumstances require additional groupings (e.g. all services running from the basement level to a second storey can be grouped together in a single group, or into one group on each side of the home);be installed within a designated vertical service chase with minimum dimensions of 89 mm × 360 mm;include access panels or hatches within the vertical chase to allow for the installation of additional services or modification of existing ones;have the vertical chases located in walls or areas that do not require modifications based on the DAR; andhave the vertical chases clearly documented in the DAR form and drawings.

12.2.2 Horizontal service chases

To facilitate future changes to the space, services (HVAC, plumbing, electrical, etc.) shall:be grouped together by floor area in a maximum of two groups per 100 m² of floor area (e.g. all services going from the vertical chase to the adjacent bedrooms on the second storey can be grouped in a single group);be installed in a designated horizontal service chase with minimum dimensions of 180 mm × 300 mm (clear interior dimension);have the horizontal chases located in walls or areas that do not require modifications based on the DAR; andhave the horizontal chases clearly documented in the DAR form and drawings.Note 1: Joist or truss cavities may be used as horizontal chases. Access hatches should be provided.Note 2: Because of factory construction and transport requirements, modular and prefabricated housing may use double floor joist construction between floors. Where this technique is used, an access between the ceiling level and floor level should be provided where a horizontal service chase is installed.

When planning module segmentation and potential future openings, designers and manufactures should:test layouts using scenarios involving:power wheelchairs;scooters;mobility aids; andsupport persons; andinvolve people with lived experience of mobility and sensory disabilities in reviewing circulation options. ,

13.1 Module and panel connections

Panel and module connections in accessible-ready modular and prefabricated housing shall not impact the owner’s ability to modify the interior space of the dwelling to meet accessibility requirements specified in the DAR (see Annex A of this Standard). ,

13.2 Pre-wiring of electrical cables

When electrical wiring is routed between two panels or modules on-site, it shall not limit the ability to modify the receptacles or switch locations complying with CAN‑ASC‑2.8:2025. ,

13.3 Routing and installation of mechanical and electrical systems

To support future accessible-ready modifications and minimize disruption during interior renovations or modifications:mechanical and electrical systems shall be designed and installed so that service chases for HVAC, plumbing, and electrical comply with Clause 13.2; andinterior non-load-bearing walls that are part of the DAR should be free of embedded mechanical systems, except where a wall cavity is designated for use as a service chase, and the chase portion is not part of the DAR.Note: In accessible-ready modular and prefabricated housing, service chases (for HVAC, plumbing, and electrical systems) should be strategically located adjacent to structural elements, without blocking access to structural post adjustments rather than within or near interior non-load-bearing walls. This approach enables future reconfiguration, such as removing or relocating partitions, without disrupting core mechanical systems or causing significant damage. ,

13.4 Accessible-ready provisions for module transportation restrictions

Modular and prefabricated housing layouts shall be designed to ensure that segmentation due to transportation limits does not interfere with future accessible-ready modifications via misalignment, mislocated services, or disruption of open spaces required for accessibility.Note 1: Transportation regulations impose dimensional limits on prefabricated modules. These limitations affect the design and assembly of modular and prefabricated housing. To comply, buildings are segmented into transportable modules or panels, which introduce structural separations, mechanical connections, and coordination/fitment challenges.This segmentation can limit the size of uninterrupted interior spaces, thereby affecting the flexibility and future adaptability of the home. For accessible-ready designs, where open layouts, clear circulation paths, and reconfigurable partitions are critical, early planning is essential to:align modular joints away from key adaptable zones;avoid placing mechanical or structural systems in areas likely to be reconfigured; andensure service continuity across modules with accessible and standardized connections.Note 2: To maintain the required open spaces for accessible-ready requirements, and to minimize shifting, twisting, or deflection in the modules, additional care may be required. This may include adding additional bracing to modules or panels for transport. This may affect accessible-ready design in unexpected ways, such as when a slight misalignment of floors or ceilings between two modules may result in unlevel floors and ceilings if the wall is removed in the future.

This Annex is a mandatory part of this Standard. ,

14.1 Sample accessible-ready housing form

ClauseFeatureCompliance method (i.e. specify how and if a feature is achieved by a method other than design requirements, or if the design requirement approach is used. If so, specify whether the design requirement is provided in a drawing set or in text form in this table.)Design14.1Module and panel connectionsExample: Design and performance requirement – Drawing PC01 (Detail drawing is provided outlining method for panel disconnection or modification for the purposes of achieving an accessible space.)Example: Panel connections are designed and positioned to be readily accessible and simple to operate, enabling panels to be attached or detached from the module with minimal disruption.14.2Pre-wiring of electrical cablesExample: Wiring is provided for the future installation of a power door. This is documented in the DAR package to be used in guiding future retrofits.Example: A separate circuit for power doors is roughed into the electrical panel. Junction boxes are provided capped designated future locations for power doors.14.3Routing and installation of mechanical and electrical systemsExample: Mechanical and electrical systems are routed out of the way of future lift and accessible path of travel locations. This is documented in the DAR package.Example: A vertical service chase is designed adjacent to a structural post from the utility room in the basement to the main floor.14.4Accessible‑ready provisions for module transportation restrictionsExample: DAR paths are not along module connections, except for a designated opening designed into the module wall to provide accessible circulation.Example: A framed opening is provided at the module connection point to provide a future accessible path of travel between rooms. This is documented with an accompanying drawing. ,

14.2 Accessible drawings

It is strongly recommended that a similar form be accompanied by a set of drawings, called Accessibility Drawings, derived from the architectural drawings submitted for a permit. These drawings should include additional information identifying all accessible-ready features. For example, walls designed to be modified as part of an accessibility retrofit should be labelled as a distinct wall type. This should include details such as wall and floor finishes, fixtures, and other relevant elements to ensure all requirements for compliance are captured.The DAR documentation is required by Clause 12 to be included in both the owner’s manual and the permit application. Including a set of DAR drawings enhances clarity and usability of the documentation by illustrating the location and nature of accessible-ready features. This supports future occupants and owners in implementing accessibility adaptation when required.Accessibility drawings (including DAR drawings) should use consistent, clearly defined symbols and labels for accessible-ready elements and should distinguish between existing accessible features and future‑ready provisions (e.g. future lift shafts, knock-out panels, reinforcement locations), so that occupants can easily understand the options available.Examples of DAR drawings include, but are not limited to, the following, as applicable to the project:A DAR general sheet showing the drawing index, symbols, legends, abbreviations, general notes, and clause cross‑references, including a clear distinction between accessible features that are installed and future-ready provisions.A DAR site and exterior access plan showing exterior accessible routes, landings, clearances, gradients, parking and garage clearances, and areas reserved for future ramps, lifts, or other exterior adaptations.DAR floor plans for each level showing accessible paths of travel, clear floor spaces, turning spaces, door manoeuvring clearances, and rooms or zones intended for future modification.A DAR wall and partition modification plan identifying walls designed to be modified as part of an accessibility retrofit as a distinct wall type, together with any non‑load‑bearing walls intended for future removal or relocation and any walls required to remain free of embedded services.A DAR module and panel connection plan and details showing module joints, connection methods, removable or knock‑out portions, framed openings intended for future accessible paths of travel, and any modular coordination requirements affecting future alterations.A DAR structural plan and details showing posts, beams, transfer members, future openings identified in the DAR, reinforcement locations, and other structural provisions coordinated for future accessibility modifications.A DAR vertical path of travel plan and sections showing reserved locations and rough‑ins for future lifts, elevators, platform lifts, or stair lifts, as applicable.DAR door, opening, and entrance plans and details showing future widened openings, threshold treatment, clearance envelopes, power door operator rough-ins, and operating control locations.Enlarged DAR bathroom plans and details showing fixture relocation zones, manoeuvring spaces, future bathing fixture conversions, reinforcement locations, and related plumbing or electrical provisions.Enlarged DAR kitchen plans and details showing future adaptable work surfaces, knee and toe clearances, appliance clearances, turning spaces, and related service coordination;Enlarged DAR plans and details for bedrooms, laundry rooms, and service rooms, where future accessibility modifications are identified in the DAR.A DAR service chase coordination plan, sections, and details showing the location and dimensions of vertical and horizontal service chases, access panels, spare capacity, and areas to remain clear for future modifications.DAR electrical plans and schedules showing dedicated spare circuits, capped junction boxes, rough-ins for future lifts, power-assisted door operators, alarms, home automation, and future control and receptacle locations.DAR mechanical and plumbing plans and details showing routing of ducts, piping, vents, and equipment in a manner that avoids conflicts with future accessibility modifications.DAR schedules, notes, and details identifying all future‑ready features, rough-ins, reinforcement locations, finish implications, and references to supporting drawings.A simple way to improve consistency across submissions is to use a standard sheet series such as DAR‑0 General, DAR‑1 Site/Exterior, DAR‑2 Floor Plans, DAR‑3 Enlarged Rooms, DAR‑4 Structural/Module Details, and DAR‑5 MEP/Controls.

This Annex is not a mandatory part of this Standard. ,

15.1 Scope

This informative Annex provides guidance for creating dwelling units that are accessible to people with Multiple Chemical Sensitivities (MCS). It supports the objectives of CAN‑ASC-2.8:2025 by specifying strategies that reduce exposure to airborne chemical contaminants and promote healthier indoor environments. This Annex applies to new construction, renovations, and retrofits of residential buildings intended to meet this Standard.People with MCS experience a wide range of triggers and sensitivities. This Annex is intended to support self identified or otherwise identified occupants with MCS and related environmental sensitivities. It is intended to be applied in a way that respects lived experience, acknowledges intersection with other disabilities, and allows occupants as much choice and control as possible over solutions. ,

15.2 Terms, definitions and abbreviations

15.2.1 Definitions

For the purposes of this Annex, the following terms and definitions apply:Air Change per Hour (ACH) —a measure of how many times the entire volume of air in a room or space is completely removed and replaced in a one-hour period.Flush-out —a period during which the building is ventilated before occupancy to remove pollutants from new materials. It is a process of replacing existing indoor air with outdoor air to reduce concentrations of VOCs and other pollutants released from new materials, which typically give off gas at a much lower rate the longer they are in use.Minimum Efficiency Reporting Value (MERV) — a measure used to rate the effectiveness of air filters.Multiple Chemical Sensitivities (MCS) — a chronic condition characterized by adverse health effects from exposure to low levels of environmental chemicals.Off-gassing — the release of airborne chemicals from materials, finishes, and products into the surrounding air.

15.2.2 Abbreviations

The following abbreviations apply to this Annex:PM 2.5 / PM 10: Particulate matter (≤2.5 or ≤10 microns).TVOC: Total Volatile Organic Compounds ,

15.3 General design principles

The following general design principles provide a foundation for reducing chemical exposures and supporting healthier indoor environments.Minimize chemical exposures through material selection and source control strategies (e.g. scent‑free policies).Ensure ventilation and filtration strategies provide consistently clean air.Support ease of maintenance and adaptability for individual sensitivities.Provide transparency to occupants about material use, maintenance practices, and performance. ,

15.4 Indoor air quality and ventilation

15.4.1 Ventilation

The following strategies outline ventilation measures that can reduce chemical exposures for occupants. Indoor spaces with MCS‑friendly features should:provide continuous mechanical ventilation exceeding local code minimums where feasible;Where local codes enforce a maximum ventilation rate for energy conservation purposes, alternative compliance paths may be pursued. Examples include additional wall insulation, higher performance windows, or improved heat recovery ventilators (HRV) and energy recovery ventilators (ERV).integrate an air quality monitoring system with the HVAC system to improve indoor air quality by detecting and automatically responding to VOCs and other pollutants; andhave air quality readings and ventilation controls available through interfaces that are accessible to people with disabilities (e.g. high‑contrast displays, tactile or auditory feedback, and digital controls compatible with assistive technologies).Note 1: Operable windows may be included to allow natural ventilation and improved air circulation. Outdoor air quality monitoring should be used to manage risks for occupants with MCS when windows are open.Note 2: Consider separate exhaust systems or airlocks for units occupied by individuals with severe MCS sensitivity.

15.4.2 Airtightness

MCS-friendly spaces should:target an airtightness level of ≤ 1.5 ACH@50Pa where achievable, through careful design and construction; andbalance airtightness with controlled ventilation strategies (e.g. mechanical ventilation with filtration) to mitigate moisture and pollutant accumulation.Note 1: This reduces the infiltration of outdoor pollutants and allows better control of indoor air quality.Note 2: Achieving a level of airtightness more stringent than that of the building codes (which is typically 2.5‑3.0 ACH@50Pa) requires intentional selection and installation of insulation, sealing of joints, and high‑performance materials. Note that some energy efficiency programs may require an airtightness of < 0.6 ACH @50Pa and some constructions have been measured to have an airtightness of 0.15 ACH @50Pa.

15.4.3 Air filtration

Air filtration measures should meet or exceed the following requirements to support occupant health:Use MERV 13+ filters. In highly polluted regions, gas-phase filtration (e.g. activated carbon) can increase air purity.Ensure filters are accessible and replaced every three to six months.Note 1: High-efficiency filters help capture fine particulates and pollutants that may otherwise trigger sensitivities.Note 2: MERV ratings indicate a filter’s ability to capture particles of specific sizes. However, use of filters with higher MERV ratings can reduce system performance and increase strain if the HVAC was not designed for that filter level.

15.4.4 Air quality monitoring

Air quality monitoring strategies can be used to measure indoor pollutants. The information collected can guide adjustments to ventilation systems or other measures so that air quality is improved when pollutant levels increase. The following recommendations support the monitoring and interpretation of indoor air quality data.Sensors should monitor levels for as many pollutants as deemed reasonable by the occupant throughout the main occupancy spaces (e.g. main living spaces), depending on whether the sensitivities are to known chemicals or not.Readings should be made accessible to occupants through displays or connected applications.Where monitoring drives automatic responses, occupants should retain the ability to temporarily adjust settings to address individual sensitivities within safe operating limits.Recommended maximum pollutant concentrations are provided below for reference and general guidance. Individual requirements vary.PM2.5: ≤ 15 ug/m³PM10: ≤ 50 ug/m³CO: ≤ 10 mg/m³ (9 ppm)O3: ≤ 100 ug/m³ (51 ppb)TVOC: ≤ 500 ug/m³Benzene: ≤ 10 ug/m³Formaldehyde: ≤ 50 ug/m³Toluene: ≤ 300 ug/m³Note 1: Continuous indoor air quality monitoring helps track pollutant levels and supports responsive ventilation strategies. Information collected from these systems provides early warnings of potential air quality issues that may affect sensitive individuals.Note 2: Achieving the lowest possible level is the preferred and desired approach. These limits, however, may provide guidance for when the lowest value may be higher than desired and where additional work may be required to mitigate the impacts.Note 3: Exposure to animals such as dogs and cats can be debilitating for people with MCS. Pet-free zones and pet-free floors should be considered.

15.4.5 Outdoor air quality considerations

Outdoor air quality directly influences indoor environments. The following should therefore be considered:Where possible, site projects away from known outdoor pollution sources (e.g. highways, industrial zones).Avoid placing outdoor air intakes near parking lots, exhaust vents, or other pollutant-emitting sources.Reference local air quality indices where available, such as the AQHI (Air Quality Health Index) and the AQI (Air Quality Index) when determining ventilation schedules and filter selection.Select non-toxic plantings and trees in outdoor landscape.Note: The quality of outdoor air directly affects indoor environments, especially when natural or mechanical ventilation is used. Monitoring and filtering outdoor air accordingly are essential to protect occupants with chemical sensitivities. ,

15.5 Material selection and finishes

15.5.1 Low-emission materials

When selecting materials and finishes, the following criteria should be applied to minimize chemical emissions into the space:Seek flooring, cabinetry, and wall finishes tested using protocols such as:CDPH/EHLB Standard Method V1.2 (California Section 01350)ANSI/BIFMA M7.1/ X7.1 (furniture)ISO 16000 series (Indoor air)Where possible, use products that have been certified by a recognized third-party program demonstrating compliance with the protocols.Note 1: It is important to consider that when using third-party certified products, individual MCS related requirements may still not be met. It is important to consider and implement other protocols, and not to rely solely on product labelling.Note 2: It has been common to have labels and certifications that may insinuate a certain performance (labels such as eco, green, etc.) however, the labelling program itself may have requirements that may not match that performance. As such users, specifiers, and designers should be familiar with what the requirements are to understand the level of performance that can be expected.

15.5.2 Avoiding hazardous substances

The following substances are known triggers and should be avoided:Added formaldehydeHalogenated flame retardantsPhthalatesIsocyanatesAntimicrobial surface treatments (unless required)Note 1: These compounds are not only common triggers for individuals with chemical sensitivities but can contribute to poor indoor air quality.Note 2: This is a non-exhaustive list. Particular emphasis should be placed on avoiding known triggers to the specific occupant(s).

15.5.3 Finishing surfaces

Surface finishes should be selected to reduce the accumulation and reintroduction of airborne or surface contaminants by implementing the following strategies:Use smooth, nonporous, cleanable surfaces.Implement natural finishes or those treated with non-toxic sealants. ,

15.6 Construction and renovation practices

15.6.1 Flush-out recommendations

The following flush-out procedures are recommended to reduce indoor pollutants before occupancy:After installation of finishes, ventilate the space continuously for a minimum of 14 days using fresh outdoor air.Alternatively, ventilate the space to achieve an outdoor air flush volume equivalent to three full air changes per hour for 48 hours, or per manufacturer recommendations for product off‑gassing where available.Where product-specific flush-out guidance is not available, refer to established methods aligned with existing standards.High-emission components should be off-gassed off-site before installation where feasible.Measuring pollutant levels using a temporary (or permanent) device during flush-out can aid in determining if additional time is necessary. The flush-out can typically be considered complete once pollutant levels fall within acceptable thresholds. It should also be confirmed that the rate of decline in pollutant levels has slowed to near asymptotic levels.Note: Methods for flush-out may vary based on climate, equipment, and specific product emissions.

15.6.2 Site protocols

During construction and renovations, the following site protocols should be enforced to minimize exposures:Prohibit smoking and fragranced products on-site during and after construction. These are frequent sources of airborne irritants and residual contaminants.Use dust management and local exhaust ventilation during installation.Clean only with fragrance-free, non-toxic cleaners. ,

15.7 Furnishings and appliances

15.7.1 Furniture recommendations

Furniture should be selected with the following considerations to reduce off‑gassing and chemical triggers:Choose solid wood or metal furniture where possible.For composite wood, select fully sealed or certified low-emission options.Where possible, use products that have been certified by a recognized third-party program.Note: Solid wood and low‑emission certified furniture reduce the amount of off-gassing from composite wood and foam materials.

15.7.2 Appliances

Appliance selections should minimize combustion sources and support cleaner indoor air through the following approaches:Use electric or induction cooking equipment with direct-vent range hoods.Avoid unvented combustion appliances. ,

15.8 Operations and maintenance

15.8.1 Cleaning

Cleaning practices should limit chemical exposures by following these recommendations:Use fragrance-free, low-toxicity cleaning agents.Where applicable, provide occupants with a list of compatible cleaning products.Open windows and use kitchen and bathroom fans when cleaning to remove VOCs from products used at a faster rate.Cleaning of common use areas, such as elevators and lobbies, should be prioritized.

15.8.2 Pest management

Strategies to address pest management in an MCS-friendly manner include the following:Use Integrated Pest Management (IPM) practices.Avoid chemical pesticides unless alternatives fail.Note 1: IPM is a proactive, holistic strategy that prioritizes prevention and non-chemical solutions to manage pests. It includes methods such as sealing entry points, reducing food and water sources, using traps, and monitoring pest activity before applying treatments. In the event chemical interventions are determined to be necessary, IPM encourages the use of the least toxic and most locally targeted methods. This approach is particularly beneficial for MCS‑sensitive environments, as it significantly reduces reliance on chemicals while also managing pests, which can create triggering conditions.Note 2: If chemical pesticides are deemed necessary, residents should be warned or informed, or both so that they can make alternate accommodation plans.

15.8.3 Maintenance plans

Maintenance plans should ensure long-term compliance with MCS-friendly practices by including the following:Develop a clear and actionable maintenance schedule for HVAC, filters, and sensors.Ensure that ventilation systems are accessible for service.Include requirements in the maintenance plan to ensure the requirements herein are maintained throughout the lifecycle of the building; however, these requirements should be integrated throughout the plan and not as a separate section. ,

15.9 Scent-free policies

A scent-free policy should address the following considerations to protect occupants with MCS.Develop a scent-free policy that considers the following guidance:Apply the policy to shared and common-use spaces, both indoors and outdoors, where occupants and visitors may be exposed to fragranced products.Minimize exposure to scented personal care products, fragranced cleaning products, and air fresheners by prohibiting their use in common areas and in building operations.Require the exclusive use of fragrance-free or verified low‑VOC cleaning, maintenance, and pest management products.Provide visible signage and occupant information to raise awareness of the scent-free policy and encourage voluntary compliance.Include procedures to respond to concerns from occupants with MCS, including accommodations such as portable air purifiers, designated scent-free zones, or scheduling adjustments.Require contractors and service providers to comply with scent‑free practices when performing work in the building.Integrate the policy into operational and maintenance plans and review them periodically with resident feedback to ensure effectiveness.Note 1: Enclosed common‑use spaces such as elevators can be especially problematic.Note 2: Scent-free policies should be developed and implemented in consultation with residents, including those with MCS and other disabilities, and should emphasize education, proactive accommodation, and non‑punitive measures. Procedures should ensure that residents are not stigmatized or penalized on the basis of disability or cultural practices, while still prioritizing health protection for occupants with MCS. ,

15.10 Education and support for residents and occupants

Educational resources for residents should include the following to support safe occupancy.Provide a user guide for residents with:product disclosures and materials overview;maintenance recommendations;indoor air quality monitoring instructions; andtips for reducing indoor pollution sources.Note: These resources should also be provided to owners, building managers, and post occupancy contractors and maintenance contractors. ,

15.11 Documentation tools

Documentation tools should be used to ensure compliance and transparency, including the following:Maintain logs for emissions data, product certificates, and flush-out procedures.Support compliance tracking with detailed checklists for each phase of the project, from design through occupancy. ,

15.12 Additional tips and considerations

The following additional measures may further support the development and maintenance of MCS‑friendly spaces.Consider incorporating indoor plants that improve air quality, provided they do not trigger symptoms.The use of standalone air purifiers with HEPA and activated carbon filters is encouraged in sensitive zones such as individual offices and bedrooms.In multi-unit or shared living environments, provide educational materials to residents about personal product choices and the impact they can have on others.In shared working or public environments, provide educational materials to users about personal product choices and the impact they can have on others.If practical, allow the future occupant to select finishes known to reduce irritation as a result of their personal MCS triggers. ,

15.13 Informative references

WELL Building Standard v2– Air Concept (https://v2.wellcertified.com/en/wellv2/air): Guidelines for improving indoor air quality through ventilation, filtration, and source control.RESET Air Standard (https://reset.build/standard/air/): Performance‑based standard focused on continuous monitoring of indoor air quality.RESET Embodied Materials Standards (https://reset.build/standard/embodied/): Framework for assessing health and environmental impacts of materials.SCS Indoor Advantage™ and FloorScore® Certifications: Third‑party certifications for low-emission materials and furnishings.https://www.scsglobalservices.com/certified-green-products-guide?program=24+25GREENGUARD Gold Certification (https://www.ul.com/services/ul-greenguard-certification): Certification ensuring products meet strict chemical emissions limits.CDPH/EHLB Standard Method V1.2 (https://www.cdph.ca.gov/Programs/cls/dehl/ehl/Pages/AQS/VOCs.aspx): Standard method for testing VOC emissions from building products.SCAQMD Rule 1168 (https://www.aqmd.gov/docs/default-source/rule-book/reg-xi/rule-1168.pdf) and 1113 (https://www.aqmd.gov/docs/default-source/rule-book/reg-xi/r1113.pdf): VOC content limits for adhesives, sealants, and architectural coatings.EPA Safer Choice Program (https://www.epa.gov/saferchoice): Product labeling program for safer chemical ingredients.EWG Cleaners Database: Resource for evaluating the safety of cleaning products.ANSI/BIFMA furniture testing protocols: Standards for emissions testing and sustainability in commercial furniture.

Note: Research findings from Accessibility Standards Canada’s Advancing Accessibility Standards Research Grants and Contributions Program informed the background research and development of this Standard. Related research reports are listed in the bibliography below. ,

16.1 Acts

Government of Canada. S.C. 2019, c. 10. Accessible Canada Act https://laws-lois.justice.gc.ca/eng/acts/a-0.6/ ,

16.2 Standards and Codes

CAN-ASC-2.8: 2025–Accessible-Ready Housing https://accessible.canada.ca/creating-accessibility-standards/can-asc-282025-accessible-ready-housingCSA/ASC B651:23–Accessible Design for the Built Environment https://accessible.canada.ca/creating-accessibility-standards/csa-asc-b651-accessible-design-built-environmentCSA/ASC B652:23–Accessible Dwellings https://accessible.canada.ca/creating-accessibility-standards/csa-asc-b652-accessible-dwellingsCSA A277-16 (R2021) Procedure for Certification of Prefabricated Buildings, Modules, and Panels A277-16 (R2025) | Codes & Standards | Product | CSA Group ,

16.3 Publications

Accessibility Now (AccessNow). 2023. Mapping Our Cities for All. https://accessnow.com/wp-content/uploads/2023/10/AN_MOCA_Report_2023_FINAL.pdfBritish Columbia Aboriginal Network on Disability Society. 2025. First Nations Accessibility Standards - A Path Forward to Inclusion. https://www.bcands.bc.ca/wp-content/uploads/First-Nations-Accessibility-Standards-A-Path-Forward-to-Inclusion-2025.pdfCanadian Association of the Deaf. 2023. Advancing Accessibility Standards for Deaf, Deaf-Blind and Hard of Hearing Canadians. https://cad-asc.ca/quiet-waves/Canadian National Institute for the Blind. 2024. Clearing Our Path: Evidence-based guidelines on accessibility in the built environment. https://clearingourpath.ca/index.php/site-map/clearing-our-path-evidence-based-guidelines-on-accessibility-in-the-built-environment-for-people-living-with-sight-loss/Carleton University. 2023. Informing Standards for Acoustics and the Built Environment. https://carleton.ca/accessibility-institute/projects/completed-projects/informing-standards-for-acoustics-and-the-built-environment/Carleton University. 2024. A Neurodivergent Lens: Recommended Practices for Neuroinclusivity. https://carleton.ca/accessibility-institute/projects/completed-projects/nd-lens/Dalhousie University. n.d. Mass Evacuation and People with Disabilities Final Report. https://cdn.dal.ca/content/dam/dalhousie/pdf/dept/maceachen-institute/ASC_ESDCReport_EN.pdfDesign For All Inc. 2023. Informing Standards Development for Federal Heritage Buildings: An Inclusive Iterative Process. https://universaldesignforall.ca/heritage-standards-development-an-iterative-process/Eyecandy SIGNS Incorporated. 2023. Advancing Communication through Signage and Wayfinding. https://static1.squarespace.com/static/623e05eb7eafe47c70b19b40/t/6450eaff4b0d97730aaf41b7/1683024642458/Report_SignageTesting_PEACH_ENG-V3.pdfFirst Nations Health Authority. 2025. A Journey Towards Accessibility – Perspectives from First Nations in British Columbia. https://fnha.ca/a-journey-towards-accessibility-perspectives-from-first-nations-in-british-columbia/First Nations National Building Officers Association. 2021. Indigenous Communities and Federal Accessibility Standards: A Situational Review. https://www.fnnboa.ca/indigenous-communities-and-federal-accessibility-standardsHidden Mobility Disabilities Alliance Ltd. 2024. Ensuring Accessibility for Persons with HMD (Limited Mobility). https://view.officeapps.live.com/op/view.aspx?src=https%3A%2F%2Fhmdproject.org%2Fwp-content%2Fuploads%2F2024%2F03%2FLimited-Mobility.-Text-only.docx&wdOrigin=BROWSELINKMawita'mk Society. 2024. Hearing Their Voices From Isolation to Self-Determination. https://mawitamk.org/report-hearing-their-voices/McMaster University. 2021. Sustainable Environment Needs to be Accessible: Understanding the Knowledge Base for Accessibility of Buildings and the Built Environment. https://accessible.canada.ca/research-and-funding/funded-research-project-database/understanding-knowledge-base-accessibility-buildings-built-environmentMcMaster University. 2024. A Framework for Accessible Heritage Buildings & Structures Retrofits. https://www.researchgate.net/publication/381769430_A_Framework_for_Accessible_Heritage_Buildings_Structures_RetrofitsNunavummi Disabilities Makinnasuaqtiit Society. 2024. Advancing Accessibility Standards through Inuit Qaujimajatuqangit. https://nuability.ca/wp-content/uploads/2025/06/AASTIQ-ENGLISH-compressed.pdfOntario College of Art and Design University. 2025. Accessible Canada, Accessible World / Un Canada accessible, Un monde accessible. https://idrc.ocadu.ca/projects/acaw-cama/report/Quadrangle Architects Limited. 2024. Heritage for All. https://humanspace.global/wp-content/uploads/2024/07/2024-HS-Heritage-for-all-Final-Report-en.pdfRealize. n.d. INDEED (INvestigating the DEvelopment of Accessibility Standards in Canada and the Inclusion/Exclusion of Episodic Disabilities. https://www.realizecanada.org/documents/summary-report-of-research-activities-and-findings-indeed-investigating-the-development-of-accessibility-standards-in-canada-and-the-inclusion-exclusion-of-episodic-disabilities/Sunnybrook Research Institute. 2025. Identifying priorities and developing collaborative action plans to improve accessible housing practice, policy, and research in Canada. https://danielshomes.ca/wp-content/uploads/2025/08/Accessible_Housing_Priorities-PLOS_One-Research-Article.pdfUniversité Laval. 2024. Reconciling Heritage Buildings Preservation with Accessibility. https://accessible.canada.ca/research-and-funding/funded-research-project-database/reconciling-heritage-buildings-preservation-accessibilityUniversity Health Network. 2021. Recommendations for Evacuating Individuals with Disabilities from the Built Environment. https://engineeringhealth.ca/wp-content/uploads/2022/11/Evacuating-Individuals-with-Disabilities-Report_English-1.pdfUniversity Health Network. 2023. Recommendations for the Inclusion of Wayfinding Technologies in Canadian Accessibility Standards. https://www.wayfindingtechproject.com/findings-1University Health Network. 2024. A Park Accessibility Framework: Making National Parks Accessible to People with Disabilities. A-Park-Accessibility-Framework-Making-National-Parks-Accessible-to-People-with-Disabilities.docxUniversity of British Columbia. 2024. PARCOURS Parks for All. https://parkaccessforall.ca/