In residential design, accessibility is governed by a tiered system of requirements outlined in the International Building Code (IBC) and detailed in the ICC A117.1 standard, Accessible and Usable Buildings and Facilities. The two primary categories for multifamily housing are Type A and Type B dwelling units.

Type A Units (Accessible): These units provide a higher level of accessibility, designed to be immediately usable by individuals with disabilities, including those who use wheelchairs. They feature more generous clearances, specific layouts in kitchens and bathrooms, and are required in a smaller percentage of total units in a building.

Type B Units (Adaptable): These units meet the minimum Fair Housing Act (FHA) requirements and are designed to be "adaptable." They provide a basic accessible route and features that can be easily modified later to accommodate a resident with a disability. Most new multifamily units fall into this category.

Here is a high-level comparison of their core requirements:

Understanding the distinction between these unit types is fundamental to compliant residential design, ensuring projects meet both legal mandates and the practical needs of future residents.

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Why Type A and Type B Accessibility Matters

Navigating accessibility requirements in residential buildings is a critical task for architects, engineers, and developers. These rules are not just building code issues; they are rooted in civil rights law, primarily the Fair Housing Act (FHA). The International Building Code (IBC) provides the "scoping" for when and how many accessible units are required, while the ICC A117.1 standard provides the technical "how-to" details for designing them.

Failing to correctly interpret and apply these standards can lead to significant problems:

• Costly Redesigns: Discovering non-compliance during plan review or, worse, after construction can lead to expensive change orders and project delays.
• Failed Inspections: Field inspectors are trained to verify specific clearances, reach ranges, and fixture placements, and even minor deviations can result in a failed inspection.
• Legal Liability: Non-compliance with FHA requirements can trigger lawsuits from fair housing advocacy groups or the Department of Justice, resulting in fines and mandated retrofits.

A common point of confusion is the relationship between the FHA, the Americans with Disabilities Act (ADA), and local building codes.

• The ADA primarily applies to public accommodations (like a building's leasing office) but generally not the dwelling units themselves.
• The FHA applies to nearly all new multifamily housing and sets the baseline for accessibility.
• The IBC and ICC A117.1 are the model codes that local jurisdictions adopt. They incorporate and often exceed the minimums of the FHA. A design that complies with the locally adopted IBC and A117.1 is generally considered a "safe harbor" for FHA compliance.

Therefore, a deep understanding of Type A and Type B unit requirements in ICC A117.1 is essential for delivering compliant, functional, and marketable housing.

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What is the difference between a Type A and a Type B accessible dwelling unit in ICC A117.1?

The primary difference is that a Type A unit is designed for full accessibility and usability from day one, while a Type B unit is designed to be adaptable for accessibility and meets the minimum requirements of the Fair Housing Act. Type A units have more stringent requirements for clear floor space, maneuvering clearances, and functional layouts, particularly in kitchens and bathrooms.

Here is a more detailed breakdown of the key differences based on ICC A117.1:

Type A Dwelling Units (ICC A117.1 §1003):

• Intent: To provide a dwelling unit that is fully functional for a person using a mobility device upon move-in.
• Kitchens: Require either a 60-inch diameter turning space or specific clearances at all appliances. For example, a U-shaped kitchen must have a 60-inch clear width. They also require accessible work surfaces and specific knee/toe clearances at sinks.
• Bathrooms: Require a 60-inch turning space (or a compliant T-shaped turn) within the room. At least one bathroom must be fully accessible, including options for a transfer tub, roll-in shower, or accessible bathtub.
• Doors: Require maneuvering clearances on both sides of the door, accommodating various approach directions.
• Overall: These units represent a higher standard of accessibility and are typically required in a smaller percentage of the total units in an R-2 occupancy, as determined by IBC Chapter 11.

Type B Dwelling Units (ICC A117.1 §1004):

• Intent: To meet the seven design and construction requirements of the FHA, ensuring a baseline of accessibility that can be easily adapted by a resident later.
• Kitchens: Require a minimum 40-inch clear path between opposing counters, cabinets, or walls. Full turning spaces are not required.
• Bathrooms: Clearances are less stringent. A turning space is not required within the room, provided the door doesn't swing into the fixture clearances. Grab bar reinforcement (blocking in the walls) is required, but the bars themselves are not.
• Doors: Maneuvering clearances are required on the push side of passage doors but are generally not required on the pull side, a significant reduction from Type A.
• Overall: This is the baseline requirement for most dwelling units in new multifamily construction. The focus is on an accessible route into and through the unit, accessible outlets and controls, and reinforced walls for future grab bar installation.

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How do I make a kitchen sink accessible per the ANSI standard?

To make a kitchen sink accessible in a Type A unit, you must meet the detailed requirements of ICC A117.1-2017 §1003.12.4. This involves providing clear floor space for a forward approach, proper knee and toe clearance underneath, and protecting the user from hot or abrasive pipes.

Here are the specific requirements for an accessible kitchen sink:

• Clear Floor Space: A 30-inch by 48-inch clear floor space must be provided for a forward approach to the sink. The clear floor space must be centered on the sink.
• Knee and Toe Clearance: To allow a wheelchair user to get close to the sink, specific clearance must be provided underneath, as detailed in ICC A117.1 §306.
  
  • Toe Clearance: At least 9 inches high from the floor and 17 to 25 inches deep.
  • Knee Clearance: At least 27 inches high at the front edge, tapering down to 9 inches high at a point 8 inches back from the front edge. The clearance must be at least 30 inches wide.
• Sink Height and Depth: The rim of the sink can be no higher than 34 inches above the finished floor. The sink bowl itself can be no deeper than 6.5 inches to ensure knee space is maintained underneath (ICC A117.1 §1003.12.4.3).
• Drain and Water Supply Protection: All drain piping and hot water supply lines under the sink must be configured to protect against contact. This is a critical safety requirement to prevent burns and abrasions. Per ICC A117.1 §606.5, this can be achieved by:
  
  • Insulating the pipes.
  • Enclosing the pipes in a protective covering or cabinet.
  • Locating the pipes out of the knee space area.
• Faucet Controls: The faucet must have lever-style, push-type, or other controls that do not require tight grasping, pinching, or twisting of the wrist to operate (ICC A117.1 §309.4). The operable parts must be located within accessible reach ranges.

For Type B units, the sink is not required to have knee and toe clearance upon construction but must be located on an accessible route.

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For a Type A dwelling unit under the 2017 ANSI A117.1, what are the specific requirements for providing both a forward and parallel approach to a kitchen cooktop, and how does this impact adjacent cabinet and appliance placement?

In a Type A unit, ICC A117.1-2017 §1003.12.5 requires an accessible cooktop to have a clear floor space that allows for either a forward or parallel approach. The choice of approach significantly impacts the kitchen layout.

Option 1: Forward Approach

• Requirement: A 30-inch by 48-inch clear floor space must be provided, centered on the cooktop, allowing a user to pull underneath. This necessitates providing knee and toe clearance under the appliance per ICC A117.1 §306.
• Impact on Design:
  
  • Adaptable Cabinetry: Since most standard cooktops are installed in a base cabinet, that cabinet must be designed to be removable to create the required knee space. The design drawings must clearly detail this feature.
  • Appliance Selection: A cooktop (without an oven below) must be used. A standard range (cooktop/oven combo) cannot accommodate this clearance. The oven must be relocated to a separate wall cabinet unit.
  • Counter Space: This approach does not require additional adjacent counter space beyond what is standard, but the structural support for the countertop must be considered once the base cabinet is removed.

Option 2: Parallel Approach

• Requirement: A 30-inch by 48-inch clear floor space must be provided directly adjacent to the cooktop, with its long side parallel to the appliance. This allows a user to approach from the side.
• Impact on Design:
  
  • Appliance Selection: This approach allows for the use of a standard range or a cooktop with an oven or cabinets below, as no knee space is needed.
  • Adjacent Cabinetry: The clear floor space cannot overlap with other appliances or permanent fixtures. This means the 30-inch space directly next to the cooktop must be kept clear, which can affect the placement of a dishwasher or refrigerator and disrupt the traditional kitchen work triangle.
  • Layout: The kitchen layout must be planned to accommodate this dedicated clear floor space without creating an awkward or inefficient workflow.

Designers must choose one of these two options and detail it correctly on the construction documents to ensure compliance.

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My project is an R-2 occupancy that must comply with both the FHA 'safe harbor' provisions and the locally adopted 2009 ICC A117.1. Where do the requirements for accessible routes to and through a Type B dwelling unit differ, and which standard's requirements must I follow?

You must follow the strictest applicable requirement to ensure full compliance. While the Fair Housing Accessibility Guidelines (FHAG) provide a "safe harbor" for FHA compliance, the locally adopted building code (in this case, referencing 2009 ICC A117.1) is the legally enforceable standard for construction permits. In most cases, the ICC A117.1 standard is more specific and often more stringent than the FHAG.

Here are key areas where the accessible route requirements for Type B units under 2009 ICC A117.1 §1004 may differ from or expand upon the FHAG:

• Maneuvering Clearances at Doors: This is the most significant difference. The FHAG is less prescriptive about maneuvering clearances on the pull side of doors within a dwelling unit. However, 2009 ICC A117.1 §1004.2.3 requires specific clearances on the push side of doors and requires a minimum 32-inch clear opening width. While it waives the pull-side clearance common in Type A units, its push-side requirements are more detailed than the general guidance in the FHAG.
• Thresholds: The FHAG allows a 3/4-inch threshold at accessible exterior doors (e.g., patios) and 1/2-inch at other doors. 2009 ICC A117.1 §1004.2.4 generally limits thresholds to 1/2-inch high, but specifically requires thresholds at accessible sliding doors to be no higher than 1/2-inch, which can be a stricter field condition to meet.
• "Usable" Doors: ICC A117.1 provides more detailed criteria for what constitutes a "usable door," including hardware requirements (§404.2.7) and opening force (§404.2.9), which are more technical than the general FHAG provisions.

Compliance Strategy:

• Design to the Code: Base your design on the locally adopted 2009 ICC A117.1 standard. This is the standard your plans examiner and inspector will use.
• Cross-Reference: Use the FHAG and its associated Design Manual as a supplementary guide, especially for understanding the intent behind the requirements.
• Strictest Standard Prevails: Where there is a direct conflict or difference in dimension, the code that provides greater accessibility (i.e., the stricter dimension or requirement) must be followed. In nearly all cases, this will be the ICC A117.1 standard. By complying with ICC A117.1, you are almost always meeting or exceeding the FHAG safe harbor requirements.
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When designing an assisted living facility, how do the requirements for Type B units in the 2009 ICC A117.1 differ from the specific needs of residents, and are there sections of the standard that should be exceeded to provide better usability?

While an assisted living facility might be required by code to provide a certain number of Type B units, these minimum standards are often inadequate for the actual day-to-day needs of the residents. Type B units are designed for adaptability, not for the high level of accessibility that residents in an assisted living environment typically require from day one.

Designers should treat the Type B requirements as a floor, not a ceiling, for accessibility in this context. Here’s how the needs differ and where to exceed the code:

• Maneuvering Space: Type B units do not require a 60-inch turning circle in bathrooms. For assisted living residents, who frequently use walkers and wheelchairs, this space is crucial for safe transfers and assistance from caregivers. Best Practice: Provide a 60-inch turning circle or T-shaped turn space in every bathroom, regardless of unit type.
• Grab Bars: Type B units only require reinforcement (blocking) in walls for future grab bar installation (ICC A117.1-2009 §1004.11.2.1). Residents in assisted living need this support immediately. Best Practice: Install grab bars at all toilets and in all showers/tubs from the outset.
• Showers: Type B units permit standard bathtubs with grab bar blocking. Many older adults find it difficult and dangerous to step over a tub apron. Best Practice: Specify roll-in or transfer-type showers with integrated seats wherever possible. This drastically improves safety and independence.
• Kitchenettes: A Type B kitchenette only requires a 40-inch clear passage. A resident using a wheelchair needs more room to maneuver. Best Practice: Provide a full 60-inch turning space in the kitchen area and ensure at least one work surface is at a lower, accessible height (34 inches max).
• Adaptable Features: Features like removable base cabinets under sinks are great in theory, but in an assisted living setting, it's better to provide the accessible configuration from the start. Best Practice: Design kitchens and bathrooms with permanent knee space under sinks.

Exceeding the minimum Type B requirements in an assisted living facility is not just good design—it's essential for resident safety, dignity, and operational efficiency for staff. The design should be based on universal design principles and reflect the reality of the user population, not just the minimum code-mandated adaptability.

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When providing an accessible kitchen sink, does the drain piping and garbage disposal need to be fully enclosed to prevent contact, or is insulation sufficient to meet the A117.1 requirement for protecting against burns and abrasions?

Insulation is sufficient to meet the technical requirement of the code, but enclosure is also an acceptable method. ICC A117.1 §606.5 (referenced for kitchens) states that water supply and drain pipes under lavatories and sinks shall be "insulated or otherwise configured to protect against contact."

Here's a breakdown of the two common compliance methods:

• Insulation: This involves wrapping the P-trap, drain lines, and hot water supply line with a purpose-made foam insulation product.
  
  • Pros: Less expensive, easy to install, preserves the maximum amount of knee space.
  • Cons: Can be damaged or removed over time, may be considered less aesthetically pleasing.
• Enclosure: This involves building a protective panel or using a removable cabinet face to conceal the pipes.
  
  • Pros: Provides a more durable and permanent barrier, offers a cleaner, more finished look.
  • Cons: Can slightly reduce the total volume of knee space if not detailed carefully, may be more expensive to fabricate.

Important Consideration for Garbage Disposals:

A garbage disposal unit itself is a major consideration. Its bulk can easily protrude into the required knee and toe clearance zone.

• The disposal unit and all associated piping must not obstruct the minimum clearances required by ICC A117.1 §306.
• Low-profile or compact disposal models should be specified.
• The disposal and its wiring must also be configured to prevent abrasion or contact. Often, this means the unit is located as far back as possible, and any exposed wiring is properly managed.

Both insulation and enclosure are valid code solutions. The choice often comes down to budget, aesthetics, and durability concerns for the specific project.

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In a Type A unit, what is the required clear floor space at a clothes washer and dryer, and must this space be centered on each appliance individually if they are side-by-side?

In a Type A unit, ICC A117.1 §1003.11 requires a clear floor space of 30 inches by 48 inches to be provided at clothes washers and dryers. This space must be positioned for a parallel approach to the appliances.

When a washer and dryer are placed side-by-side, the standard does not require two separate, perfectly centered 30"x48" clear floor spaces. Instead, the clear floor space must be positioned to allow use of the controls and doors of both appliances.

Practical Application:

• A single, larger clear floor space, such as one that is 60 inches wide by 48 inches deep, positioned in front of the two adjacent appliances, is the most common and effective way to comply.
• This single space allows a person in a wheelchair to move sideways to access the controls, load, and unload both the washer and the dryer without repositioning.
• The key is that from a point within the clear floor space, the user must be able to reach the controls and operate the doors. Ensure the appliance doors, when open, do not obstruct the required clear floor space.

The intent of the code is functionality. A single, shared clear floor space for side-by-side units is more functional and is a universally accepted method of compliance among plan reviewers and inspectors.

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Does the ANSI standard specify a maximum height for the operable part of a window latch in a common area of an R-2 occupancy?

Yes, it does. In a common area of an R-2 occupancy (such as a community room or lobby) that is required to be accessible, all operable parts, including window latches, must comply with ICC A117.1 §309, Operable Parts.

This section requires operable parts to be placed within accessible reach ranges as defined in ICC A117.1 §308. The specific maximum height depends on the direction of approach:

• Forward Reach: If the user can approach the window head-on, the maximum high forward reach is 48 inches above the finished floor. The minimum low reach is 15 inches.
• Side Reach: If the user must approach the window from the side (parallel), and there is no obstruction, the maximum high side reach is 48 inches above the finished floor. If there is an obstruction (like a counter or sill) up to 10 inches deep, the max height remains 48 inches. If the obstruction is deeper, the max height is reduced.

Therefore, for a typical window in an accessible common area, the window latch and any other opening mechanisms must be located no higher than 48 inches above the finished floor. Additionally, the hardware must be operable with one hand and not require tight grasping, pinching, or twisting of the wrist.

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Common Mistakes and Misinterpretations

• Confusing Type B with ADA: Designers sometimes assume a Type B unit is fully "ADA compliant." The ADA does not typically govern the interior of dwelling units; that is the role of the FHA and the IBC. Type B is a minimum standard, not a fully accessible one.
• Forgetting Local Amendments: States like California (CBC), Florida (FBC), and Texas (TAS), and cities like New York have accessibility codes that are significantly different and often stricter than the model ICC A117.1. Always design to the locally adopted code first.
• Improper Adaptable Details: Simply putting a note on the drawings that says "removable cabinet" is not enough. The details must show how the cabinet is constructed to be easily removed without damaging the countertop or adjacent finishes.
• Ignoring Door Swing Encroachment: The required clear floor space at fixtures and appliances must remain clear. A common mistake is allowing a bathroom or closet door swing to obstruct the turning circle or the clear space at a fixture.
• Missing Pipe Protection: Forgetting to insulate or enclose pipes under sinks is one of the most frequent (and easily fixable) accessibility failures found during field inspections.

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Jurisdictional Variations to Watch For

While the ICC A117.1 standard provides a strong baseline, accessibility is an area with significant jurisdictional variation. Always verify the specific requirements of the state and local building codes where your project is located.

• California: The California Building Code (CBC) Chapters 11A and 11B have extensive and unique requirements for residential accessibility that go far beyond the model codes. The terminology and specific dimensions are different.
• Florida: The Florida Building Code, Accessibility, contains specific amendments and requirements that must be followed.
• Texas: Projects must comply with the Texas Accessibility Standards (TAS), which has its own set of technical requirements.
• New York City: The NYC Building Code has specific accessibility provisions, particularly for residential buildings, that amend the model IBC.

Best Practice: Never assume the model code is the final word. Obtain the full, state-adopted building code and any local amendments before beginning the design of any multifamily project.

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FAQs

‍What triggers the requirement for the more stringent Type A units?

The International Building Code (IBC) Chapter 11 scopes this. In R-2 occupancies (apartments, condos), Type A units are typically required in buildings with more than 20 dwelling units, often tied to buildings that have elevators. The exact number is a percentage of the total units.

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Are grab bars required to be installed in Type B bathrooms?

No. Type B units only require continuous wood blocking or another form of reinforcement to be installed within the wall framing around the toilet, tub, and shower. This allows for the easy installation of grab bars by a resident in the future.

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Can a garbage disposal be installed in an accessible sink?

Yes, provided the unit itself and its plumbing connections do not encroach on the required knee and toe clearance space under the sink. This often requires specifying a compact disposal model and careful coordination with the plumber.

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References

1. American National Standard – ICC A117.1 (2017) – official preview/documentation page for the 2017 edition of the standard: https://codes.iccsafe.org/content/icca117-12017/american-national-standard 
2. Chapter 4 – Accessible Routes” from ICC A117.1-2017 – which covers slope, cross-slope, clear widths, and accessible route components. https://codes.iccsafe.org/content/icca117-12017/chapter-4-accessible-routes 
3. ANSI Blog: “ICC/ANSI A117.1-2017: Accessible & Usable Buildings and Facilities” – overview of major changes and how the standard fits into the accessibility ecosystem. https://blog.ansi.org/ansi/icc-ansi-a117-1-2017-accessible-buildings 
4. Supplement 1 to A117.1 — 2017 Edition” – details on the 2024 approved supplement adding adult changing station requirements (Section 613) to the 2017 edition: https://codes.iccsafe.org/content/IBCACCPB2024P1/supplement-1-to-a117-1-2017-edition 
5. HUD – Fair Housing Act: “Seven Principles” of Design & Construction Compliance: https://www.hud.gov/program_offices/fair_housing_equal_opp/design_and_construction

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