Lesson 3: Accessible route, doors, and doorways

Reading

Chapter 4 of A117.1 covers the accessible route, the continuous, unobstructed path a person using a wheelchair or another mobility aid follows through a building or site. This lesson looks at Section 402, which defines what a route can be made of, Section 403, which sets the rules for the walking-surface portions of that route, and Section 404, which covers doors and doorways, one of the most frequently inspected items on any GCHS project. Ramps, curb ramps, stairs, handrails, and elevators, the other components an accessible route can include, get their own full treatment in the next lesson.

What an accessible route can consist of (402)

Section 402 defines an accessible route as one built from walking surfaces that comply with Section 403, doors and doorways that comply with Section 404, gates, and, where the route needs to change elevation, ramps, curb ramps, blended transitions, elevators, or platform lifts. A route made only of stairs is never accessible on its own, no matter how well the stairs themselves are built; some component along the path has to provide a way around any change in level. This lesson focuses on the flat, walking-surface portions of that route and on doors; the sloped and vertical-circulation components are covered in the next lesson.

Walking surface slope and cross slope (403)

Section 403 treats a walking surface differently from a ramp based on how steep it is. A running slope of 1:20 or less is simply a walking surface; anything steeper has to be designed and detailed as a ramp instead, which brings in the ramp-specific rules covered in the next lesson. Independent of running slope, Section 403 also caps cross slope, the tilt across the direction of travel, at 1:48 maximum on any walking surface. A sidewalk or hallway that sheds water by sloping too steeply from one side to the other can fail this requirement even if it is perfectly flat in the direction someone is walking.

Clear width of walking surfaces (403)

Section 403 sets the minimum clear width of a walking surface at 36 inches for an interior route and 48 inches for an exterior route, with a narrower 32-inch minimum allowed only for segments up to 24 inches long, separated by full-width segments at least 36 inches wide and 52 inches long in new construction (48 inches long in existing buildings). An interior hallway on a GCHS rehab project has to hold that 36-inch clear width continuously, not just at its widest point; a single piece of furniture, a mechanical chase, or a poorly placed door swing that narrows the hall below 36 inches over any real distance breaks compliance even where the rest of the hallway is generous.

Door clear opening width (404)

Section 404 measures a doorway not by the door's nominal size but by its actual clear opening, the space available with the door open. The general minimum clear opening width is 32 inches. Where an opening is more than 24 inches deep and has no door at all, such as a thick-wall passage between two rooms, the minimum clear opening width increases to 36 inches. This distinction matters on older GCHS rehab houses, where a deep exterior wall or an added storage nook can create exactly that kind of doorless, deep opening. Measuring the clear opening rather than the door itself also means a door that looks generously sized when closed can still fail once it is checked with a tape measure at 90 degrees open, since hinges, stops, and the thickness of the door leaf all eat into the usable width.

Maneuvering clearances at doors (404)

Section 404's Table 404.2.3.2 sets the level, clear floor space required on each side of a door so a wheelchair user can actually reach and operate it, and the required space changes with the direction of approach, which side of the door a person is on, and whether the door swings toward or away from them. Rather than reproducing the full table, it helps to see the pattern through a few representative figures. On the pull side of a door approached head-on, Section 404 calls for roughly 60 inches of clearance perpendicular to the doorway, plus about 18 inches of clear space beyond the latch side of the door. On the push side of that same head-on approach, the clearance required is smaller, about 52 inches in new construction, reduced to about 48 inches where the project qualifies as existing construction. Other approach directions, such as a hinge-side or latch-side approach, carry their own combinations of perpendicular and latch-side clearances in the same table. The pattern to remember is that the pull side of a door generally demands more maneuvering room than the push side, and that existing buildings get modest relief compared to new construction.

Thresholds (404)

Section 404.2.4 limits a doorway threshold to 1/2 inch maximum in height and also requires compliance with Sections 302 and 303. A square, unbeveled vertical edge can be no higher than 1/4 inch under Section 303.2. Changes greater than 1/4 inch through 1/2 inch require a bevel no steeper than 1 vertical to 2 horizontal under Section 303.3. The exception for an existing or altered threshold permits a height of 3/4 inch maximum, provided that the edge on each side is beveled at a slope no steeper than 1:2 for the height above 1/4 inch. These are the change-in-level principles covered in Lesson 2, applied at doorways, and they are useful items to check during a GCHS pre-construction walkthrough.

Opening force and hardware (404)

Section 404 limits the force needed to open an interior hinged or sliding door to 5 pounds maximum. Operating hardware, the lever, pull, or latch a person actually touches, has to sit between 34 and 48 inches above the floor and has to be operable with one hand, without requiring a tight grasp, a pinch, or a twist of the wrist, which is the same operable-parts logic from Section 309 in the previous lesson. A round door knob fails this rule outright; a lever handle at the right height satisfies it.

Practice questions

Glossary

Accessible route

A continuous, unobstructed path built from compliant walking surfaces, doors, and, where needed, ramps, curb ramps, elevators, or platform lifts, under Section 402.

Running slope

The slope of a surface in the direction of travel; 1:20 or less is a walking surface, steeper requires ramp design, under Section 403.

Cross slope

The slope of a surface perpendicular to the direction of travel, capped at 1:48 maximum on walking surfaces, under Section 403.

Clear opening width

The actual usable width of a doorway with the door open, not its nominal size; 32 inches minimum generally, under Section 404.

Maneuvering clearance

The level clear floor space required on each side of a door, sized differently by approach direction and side, under Table 404.2.3.2.

Threshold

The raised strip at the base of a doorway. A square, unbeveled edge is limited to 1/4 inch. Ordinary thresholds are limited to 1/2 inch overall, with beveling required above 1/4 inch. The 3/4-inch exception applies to an existing or altered threshold with bevels on both sides no steeper than 1:2 above 1/4 inch (303.2, 303.3, 404.2.4).