What’s an Accessible Route Within Dwelling Units?

What is Considered an Accessible Route Within a Type B Dwelling Unit?

by Kimberly Paarlberg, RA Senior Staff Architect, ICC

Note: References throughout this article are from the 2012 International Building Code (IBC), or the 2009 ICC A117.1 Accessible and Usable Building and Facilities (ICC).

ICC technical staff answers questions over the phone or through email as part of their service to Members. The title of this article is a common question that comes up:

So, by requiring an “accessible route” within a Type B unit, is the intent to require turning circles in every room and/or maneuvering clearances at all doors? There are allowances for institutional and residential buildings to not have elevators between floors (IBC 1107.7), but for this article, we will assume that either a building elevator is provided, or we will focus only on the ground floor where the Accessible, Type A or Type B units are provided.


An accessible route intended to be fully accessible to a person using a wheelchair is described in Chapter 4 of the A117.1. Elements include walking surfaces, doors, ramps, curb cuts, elevators and platform lifts (ICC 402.2). The route has to be wide enough to allow for a person using a wheelchair to move throughout the space. A maneuvering clearance is provided at doors to allow some- one to reach the door hardware, maneuver out of the swing of the door so the door can open and then move into the opening through the doorway (ICC 404). Floor surfaces must be firm and stable (ICC 302). Thick carpets with thick padding make it very difficult for a person using a wheelchair to maneuver, similar to trying to move through loose stones or sand. When dealing with a change in level, there are options of curb cuts, ramps, elevators and, where permitted by IBC 1109.8, platform lifts.

Accessible, Type A and Type B units are scoped in Group I and R (IBC 1107). When a person walks or rolls into a residential or institutional facility, all public spaces and corridors would be required to comply with the accessible route provisions in ICC Chapter 4. This includes a route from any arrival points, (such as the accessible parking or drop off), to an accessible building entrance; and from there to the shared areas in the building (e.g., lobby, cafeteria, mail room, laundry, activity rooms) and to the front door of all the Accessible, Type A and Type B dwelling or sleeping units. The self-same accessible route is also required within any Accessible or Type A units (ICC 1002.3 through 1002.8, 1003.3 through 1003.8). However, the “accessible route” requirements within a Type B unit are less stringent and are defined in ICC 1004.3 through 1004.8. To fully understand the requirements, it is important to look at the limits of the references:

Type B units are defined in the IBC as “consistent with the design and construction requirements of the federal Fair Housing Act (IBC 202).” The basic idea is that a Type B unit is required to be useable by a person in a wheelchair, but it is not necessarily wheelchair friendly. Sections 1004.3 through 1004.8 provide specific references as to what is considered a Type B accessible route.

The front door to the unit must provide a 32-inch clear width (typically a 3’-0″ door), have maneuvering clearances on both sides (to allow for ingress and egress), have lever hardware and a smooth bottom surface on the push side (ICC 404, 1004.5.1). The other doors within the unit have to provide only a 31-3/4″ clear width (ICC 1004.5.2.1). This can be met with most standard 2’-10″ doors. Door hardware can include door knobs that meet the general egress provisions for door hardware (IBC 1008.9.1).Untitled7

The route does not have to reach every living space within the Type B unit. Non-accessible areas can include areas such as a raised dining area, a sunken seating areas in a living room, or a mezzanine sleeping loft, as long as you can get around those non-accessible areas to reach the other areas within the unit (ICC 1004.3.1). While the route throughout the unit does have to be at least 36 inches wide (ICC 403.5, 1004.4.1), the floor surface could be anything, including a shag carpet with double padding, if desired. Turning spaces are not required in any room within the unit. The bathrooms that provide clearances at fixtures (either Option A or Option B) have to have a 30-by-48-inch wheelchair space past the swing of the door (ICC 305.3, 1004.11.2.1), but not a turning space. While the standard thresholds at doors or at changes in floor materials are 1/2-inch maximum, a 4-inch step down between the interior and exterior surfaces is permitted to an exterior deck (ICC 1004.4.2), and a 3/4-inch threshold is permitted at sliding doors (ICC 1004.5.2.2) providing access to that deck.

If a Type B dwelling or sleeping unit includes a change in level from a step to a story, there are several options: Ramp requirements within the unit are the same as a ramp anyplace else in the building (ICC 405, 1004.6). However, given the size requirements, ramps are not common within a dwelling or sleeping unit. Any type of passenger elevator can be used to provide an accessible route within a dwelling unit (IBC 1109.7, ICC 407, 408, 409, 1004.7). The elevator safety standard, ASME A18.1, allows for private residence elevators to be used to provide a route between stories within or serving an individual dwelling or sleeping unit. A private residence elevator is not permitted in other uses. Platform lifts, either inclined or vertical, can be used to pro- vide a route between levels within a dwelling or sleeping unit (IBC 1109.8 Item 4, ICC 410, 1004.8). The platform lift safety standard, ASME A18.1, does limit the rise of a platform lift to 14 feet maximum. A platform lift does allow for a person in a wheelchair to move their device onto the lift. A chair lift that provides only a seat, while it may aid per- sons who have mobility issues, is not permitted as part of a required accessible route.Untitled8

A multi-story unit in a building with elevator access outside the unit is permitted to be accessible only on the level with elevator access (IBC 1107.7.2), provided that level has a living space and a toilet room. The 2015 IBC adds that if the Type B unit includes a kitchen, the kitchen also must be on that level. The intent is that if someone has a temporary disability, they can at least have access to the minimum facilities in the unit. Best design practice would allow for a bedroom area and full bath- room on the accessible level, however, this is not a requirement. Many designers do include this feature for homes where the idea is to allow for “aging-in-place.” A family could have such a need for a variety of reasons while living in their home, such as for a family member recovering from an operation, injury or illness that does not allow or limits the use of stairways; or a visiting family member or friend who cannot use or has difficulty using stairways.

Type B units, while consistent with Fair Housing Act requirements, do not provide, nor are they intended to provide, the same level of access for a person using a wheel- chair as that which is found in public area, Accessible or Type A dwelling or sleeping units. IBC 1107.2 recognizes this in allowing for elements of Accessible or Type A units to be permitted within Type B units since they offer a higher level of accessibility. The ICC A117.1 has a special study group that pro- posed changes to make the requirements between the different types of dwelling and sleeping units in the 2009 edition have a clearer “step-down”’ of requirements.

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