11.1 Scoping Accessible, Type A, and Type B Units (IBC 1108)
Key Takeaways
Units required to be Type A may be built as Accessible units, and units required to be Type B may be built as Accessible or Type A units (IBC 1108.2).
Group R-1 and R-2 non-apartment uses (dormitories, boarding houses) provide Accessible units per Table 1108.6.1.1, which separates units with and without roll-in showers.
R-2 apartment houses, monasteries and convents with more than 20 units provide Type A units for at least 2 percent, counted across all R-2 units on the site.
In I-1, I-2, R-1, R-2, R-3 and R-4 structures with four or more units intended as residences, every such unit is a Type B unit unless 1108.7 reduces the count.
Without elevator service, only ground-floor (accessible entrance) story units must be Type B; site impracticality, multistory units and flood hazard areas can reduce Type A and B counts.
11.1 Scoping Accessible, Type A, and Type B Units (IBC 1108)
Three Unit Types in the IBC
| Unit | Standard | Intended level | Typical use |
|---|---|---|---|
| Accessible unit | A117.1 Section 1102 | Fully accessible at occupancy | Hotels, dormitories, nursing homes, hospitals, assisted living |
| Type A unit | A117.1 Section 1103 | Accessible with some adaptable features (removable base cabinets, reinforcement) | Apartments: 2% of units in larger R-2 sites |
| Type B unit | A117.1 Section 1104 | Basic usability, consistent with the Fair Housing Accessibility Guidelines | Every unit in most residential structures with four or more units |
IBC 1108.2: units required to be Type A may be designed as Accessible units; units required to be Type B may be designed as Accessible or Type A units. A higher type always satisfies a lower requirement.
Accessible spaces (1108.3): Rooms and spaces available to the general public or to residents and serving Accessible, Type A or Type B units are accessible, including toilet and bathing rooms, kitchens, living and dining areas and exterior spaces such as patios, terraces and balconies (exceptions: stories exempted by 1108.4, recreational facilities per 1111.2, and impervious Type B decks or balconies up to 4 in. below the interior floor).
Accessible route (1108.4): At least one accessible route connects accessible entrances with the primary entrance of each Accessible, Type A and Type B unit and with the spaces serving them. Exceptions include site conditions outside the owner's control (a vehicular route with complying parking may substitute), I-3 and R-2 buildings where the required units and all common and public areas are on an accessible route, R-1 multistory units with an accessible level meeting Accessible-unit criteria, and stories exempted under 1108.7.
Group I Scoping (1108.5)
| Facility | Accessible units | Type B units |
|---|---|---|
| I-1 Condition 1 | 4%, not less than one | Every unit in structures with four or more residential units |
| I-1 Condition 2 | 10%, not less than one | Same |
| I-2 nursing homes | 50% of each type, not less than one | Same |
| I-2 general hospitals, psychiatric and detoxification | 10%, not less than one | Same |
| I-2 rehabilitation (mobility) | 100% | - |
| I-3 | 3% of sleeping units, not less than one per classification level, plus one per special-purpose cell type | - |
In I-1 and I-2 facilities, a portion of the Accessible units (50% or 90% as listed) may use assisted-toileting water closets (IBC 1110.2.2) and assisted-bathing roll-in showers (1110.2.3) instead of the standard A117.1 fixtures.
Group R Scoping (1108.6)
R-1 (hotels, motels, transient boarding houses)
Accessible units per Table 1108.6.1.1, dispersed among classes of units:
| Total units | Without roll-in showers | With roll-in showers | Total Accessible units |
|---|---|---|---|
| 1 to 25 | 1 | 0 | 1 |
| 26 to 50 | 2 | 0 | 2 |
| 51 to 75 | 3 | 1 | 4 |
| 76 to 100 | 4 | 1 | 5 |
| 101 to 150 | 5 | 2 | 7 |
| 151 to 200 | 6 | 2 | 8 |
| 201 to 300 | 7 | 3 | 10 |
| 301 to 400 | 8 | 4 | 12 |
| 401 to 500 | 9 | 4 | 13 |
| 501 to 1,000 | 2% of total | 1% of total | 3% of total |
| Over 1,000 | 20, plus 1 per 100 over 1,000 | 10, plus 1 per 100 over 1,000 | 30, plus 2 per 100 over 1,000 |
On a multiple-building site, structures with more than 50 units are counted individually; structures with 50 or fewer units are counted together. The 2024 IBC adds exceptions where every unit has showers and none has a bathtub. Every R-1 unit intended to be occupied as a residence in a structure with four or more such units is a Type B unit. Small owner-occupied R-1 buildings with five or fewer units are exempt from Chapter 11 (1103.2.11).
R-2
| R-2 type | Requirement |
|---|---|
| Live/work units (1108.6.2.1) | Nonresidential portion accessible; residential portion Type B where four or more live/work units |
| Apartment houses, monasteries and convents (1108.6.2.2) | More than 20 units: at least 2%, not less than one, Type A units, counting all R-2 units on the site (existing structures do not count) and dispersed; every unit in structures with four or more units is Type B |
| Other R-2 (dormitories, fraternities, sororities, congregate living, boarding houses) (1108.6.2.3) | Accessible units per Table 1108.6.1.1; Type B in structures with four or more units; bedrooms count as sleeping units |
R-3 and R-4
- R-3 with four or more units intended as residences in a single structure: all Type B. The 2024 IBC also requires Accessible units per Table 1108.6.1.1 in transient R-3 congregate living facilities and boarding houses.
- R-4 Condition 1: at least one Accessible sleeping unit; Condition 2: at least two; Type B in structures with four or more sleeping units.
Reducing Type A and Type B Counts (1108.7)
| Section | Rule |
|---|---|
| 1108.7.1 No elevator | Only units on stories described in 1108.7.1.1 and 1108.7.1.2 must be Type A and Type B. At least one story with an accessible exterior entrance has all its units Type B; additional stories qualify where the slope between their entrance and arrival points within 50 ft is 10 percent or less |
| 1108.7.2 Multistory units | A multistory unit without elevator service need not be Type B; with elevator service to one floor, that floor is the primary entry, complies as Type B and contains the living area, kitchen and toilet if provided |
| 1108.7.3 Elevator to lowest residential story only | Only units on that story are Type B |
| 1108.7.4 Site impracticality | On multiple nonelevator buildings, the Type B count may drop to the percentage of the site with pre-development grades under 10 percent, but not below 20 percent, with additional conditions |
| 1108.7.5 Flood hazard areas | Type A and B not required in nonelevator buildings where the required floor elevation is more than 30 in. above, and more than 10 percent slope from, arrival points within 50 ft |
Worked Example
A new four-story R-2 apartment building with an elevator has 96 units; a second 24-unit building without an elevator stands on the same site.
- Type A: the site has 120 R-2 units (more than 20), so 2% = 2.4, giving 3 Type A units, dispersed among unit types (and among the buildings where units qualify).
- Type B, elevator building: all 96 units (any not Type A) are Type B.
- Type B, nonelevator building: only units on the story with the accessible entrance (and any other qualifying story under 1108.7.1.2) must be Type B.
A new 180-room hotel (Group R-1) is being reviewed. How many Accessible units with roll-in showers does IBC Table 1108.6.1.1 require, and how many Accessible units in total?
2 with roll-in showers; 8 total
1 with roll-in showers; 6 total
2 with roll-in showers; 7 total
3 with roll-in showers; 10 total
A new apartment complex has three R-2 buildings with a total of 150 dwelling units on one site. How many Type A units does IBC 1108.6.2.2.1 require?
2
3
4
8
In a new Group I-2 nursing home, what portion of the sleeping units must be Accessible units under IBC 1108.5.2.1?
10 percent, the same rate as general-purpose hospitals
4 percent, the rate used for Group I-1 Condition 1
100 percent, as in rehabilitation facilities
50 percent, but not less than one, of each type
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