Adaptable, Accessible, Type A, Type B, Mobility Units…What are the differences?

The terminology used in residential design and construction to describe a dwelling unit's level of accessibility gets confusing rather quickly. For example, some professionals in the construction industry refer to Type A units as "accessible units". Some also call apartments in publicly-funded projects "accessible units" as well. And in my experience, many designers are unfamiliar with what an "adaptable" unit is.

With all the terminology used, discerning the correct terminology can be difficult. To remove the mystery I'm going to explain the differences amongst five terms commonly used in the design and construction of multi-family housing in Chicago. Some terms we use here may not be present in codes just in other jurisdictions, so it's important for architects and developers to be aware of this and not assume the terminology is universal.

This discussion refers to the 2019 Chicago Building Code, which becomes mandatory on August 1, 2020.

To start let's go over Type A and Type B, which are two kinds of adaptable units. The Chicago Building Code defines “adaptable dwelling unit” in Chapter 14B-202 of the code, as “a dwelling unit constructed and equipped so it can be converted with minimal structural change for use by persons with different types or degrees of disability.”

A Type A unit is a kind of adaptable dwelling unit designed to meet the provisions of ANSI 2009, Section 1003. Type B is another kind of adaptable dwelling unit designed to meet the provisions of ANSI 2009, Section 1004. Neither Type A nor Type B are accessible units.

For buildings that are in the R-2 Residential occupancy group, all Type A and Type B units are adaptable units if built as part of a covered dwelling. Covered multifamily dwellings are dwelling units in buildings containing four or more units with one or more elevators, and all ground floor units in buildings containing four or more units, without an elevator. However, keep in mind the term adaptable units is not used in ANSI 2009 or IBC 2018 – it is only defined in the Chicago Building Code.

Type A and Type B units are adaptable by the nature of their design and construction requirements. The code for these units specifically is written to require adaptable features that can be modified or provided after the first occupancy.

A full list of the items that are adaptable is not provided in the code, but generally, it does allow for items such as removable base cabinets for a forward approach to a sink, countertop heights being adjustable, and reinforcing in the walls for the future installation grab bars at bathing fixtures.

What's adapted depends on the tenant living there and what they need to adapt to live there. The idea is the unit is set up to allow adaptability to occur in the future. Hence why an item like reinforcement is needed in the bathroom for grab bars, but the grab bars themselves do not need to be installed at first occupancy. The tenant living there may need a particular type of grab bar or need it installed a certain way to best accommodate their needs.

It's common to hear people say they need accessible units on a project in Chicago when in actuality they mean a project requires Type A units. This commonly occurs because a Type A unit has more stringent requirements beyond that of a Type B unit. Type B units are consistent with the design and construction requirements of the federal fair housing requirements and ANSI Section 1004. Type A units are constructed to meet ANSI Section 1003 and local code requirements, which go beyond the scope of Type B units. Hence it's easy to see why it can be misconstrued as an accessible unit.

If both Type A and Type B dwelling units are adaptable, what is an accessible unit? Per the Chicago Building Code, 14B-202, it is defined as “a dwelling unit or sleeping unit that complies with this code and the provisions for Accessible units in ICC A117.1”.

The Chicago Building Code does not require accessible units in R-2 multifamily construction. Projects with other occupancy classifications may have to provide accessible units in accordance with ANSI 2009, Section 1002 (see the table above).

An accessible unit is a dwelling unit that complies with the aforementioned code section, but it's not considered an adaptable unit as Section 1002 does not contain the language allowing for things to be installed at a later time or adjusted later. An accessible unit is intended to be accessible at first occupancy.

A voluntarily-built accessible unit will count towards the requirement for Type A and Type B units. The Chicago Building Code explicitly states in Section 1107.2 that “units required to be Type A units are permitted to be designed and constructed as Accessible units. Units required to be Type B units are permitted to be designed and constructed as Accessible units or Type A units.” This is not a requirement for projects with an R-2 occupancy in Chicago, and for this reason, I've yet to see any units designed or constructed as accessible units.

There's a fifth and final type of unit that needs to be mentioned and that is best described as a mobility unit. It's worth mentioning that people in the design and construction industry informally refer to mobility units as accessible units, but the two shouldn't be conflated because mobility units are not related to the ANSI Section 1002 on accessible units. Additionally, requirements for when to build accessible units are regulated by local codes, and requirements to build mobility units are regulated by federal codes.

All federally-assisted new construction housing developments with 5 or more units must design and construct 5 percent of the dwelling units (with a minimum of one unit) to be accessible for persons with mobility disabilities.

Mobility units must be constructed in accordance with the Uniform Federal Accessibility Standards (UFAS) or a standard that is equivalent, like the 2010 ADA. In UFAS the units are simply defined as a “dwelling unit” and do not further categorize the units with different names. To help with clarification it is common to refer to these as mobility units as they are accessible for people with mobility impairments.

The best way to comprehend the terminology is to understand the codes that are applicable to a project. If you know the codes that apply, you know what codes don’t apply. Meaning that if a term is used, it can be discerned quickly exactly what the person is referring to.