Chapter 18 Barrier- Free Design Flashcards Preview

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Flashcards in Chapter 18 Barrier- Free Design Deck (23):

Barrier Free Design

called universal design, should be an integral part of every building and interior space



-is a civil rights law -does not cover single or multi-family housing; multi-family housing is regulated by the Fair Housing Act and some state laws


accessible route

continuous unobstructed path connecting all accessible spaces in a building or facility - Min. clear width for accessible route is 36” continuously, 32” clear at passage points, such as doorways - Minimum passage width for two wheelchairs is 60”; if route less than 60”, passing spaces 60x60” required every 200’; see fig. 18.2a, b



Min. clear width for accessible route is 36” continuously, 32” clear at passage points, such as doorways Minimum passage width for two wheelchairs is 60”; if route less than 60”, passing spaces 60x60” required every 200’; see fig. 18.2a, b


Opening Force of Doors

- Maximum opening force required to push/pull open interior hinged door cannot be more than 5lbs-ft.; this force does not include force necessary to retract latch bolts or disengage other devices holding door closed - Automatic doors, power-assisted doors can be used if they meet the applicable standard - When closers used, sweep period of door must be adjusted so from 90-degree opening, door will take 5 seconds to move to point 12 degrees from latch



-Thresholds at doorways cannot exceed ½” in height, must be beveled so no slope on threshold greater than 1:2 -Operating devices must have easy-to-grasp shape, including lever handles, push-type mechanisms, U-shaped handles -Round-shaped knobs should not be used -Hardware for accessible doors cannot be mounted less than 34 or more than 48” above finished floor


Toilet rooms

5' dia. door have a minimum 32" clear width -Grab bars must be provided as illustrated, mounted 33-36” above floor -Toilet paper dispensers must be installed with centerline between 7 & 9” in front of water closet, and with the outlet of dispenser between 15 & 48” above floor



- Urinals must be of stall or wall-hung type, with elongated rim at max. 17” above floor. Clear floor space 30x48” must be provided in front of urinal, which may adjoin/overlap an accessible route


Lavatories & Sinks

Must be designed to allow wheelchair-bound person to move under fixture to allow use of basin & water controls Faucets must be operable with one hand; cannot require tight grasping, pinching, or wrist twisting – lever-operated, push-type, automatic control mechanisms acceptable Mirrors above lavatories/countertops must be mounted with bottom edge 35” max. above floor Max. height of lavatory/sink above floor is 34



Seat required in smaller shower stall configuration, while folding seat required in larger configuration if permanent seat is provided Grab bars must be provided, mounted 33-36” above floor


Floor Surfaces

Floor surfaces must be stable, firm, slip-resistant Static Coefficient of Friction (SCOF) is used to measure skid resistance. A SCOF of 0.5 or more is desirable to minimize accidents caused by slipping ADA recommends 0.6 for accessible routes, 0.8 for ramps Level changes require transition to meet the following requirements: if less than ¼”, may be vertical, with no edge treatment


Floor Level Change

If less than ¼”, may be vertical, with no edge treatment If change is ¼” to ½”, must be beveled with slope no greater than 1:2 Changes greater than ½” must be accomplished with a ramp meeting requirements



Must have firm cushion or no backing Must have level loop, textured loop, level cut-pile, or level cut/uncut pile texture with max. pile height of ½” Must be securely attached to floor Must have trim along all lengths of exposed edges



Ramps are required to provide a smooth transition between elevation changes for wheelchair-bound & mobility-impaired people Max. slope is 1:12 (1” per foot) Max. rise is 30”; greater change requires landing before next ramp Minimum clear width 36”, with landings at least as wide as widest ramp Landings min. 60”long; if ramp changes direction, landing must be 60” square min. Ramps rising more than 6”, or lengths longer than 72” must have handrails both sides, 34-38” above ramp surface Where handrails not continuous between runs, must extend 12” horizontally beyond top/bottom of ramp segment; must be 1-1/4 to 2” diameter



Max. riser 7”, min. tread 11”, ref. fig. 12.9 Open risers not permitted Inside handrail on switchback or dogleg stairs must always be continuous as it changes direction Stairway handrails must be continuous on both sides Handrails must be 34-38” above stair nosings, gripping surface 1-1/4-2”, clear space between handrail & wall of 1-1/2”; ref. fig. 12.17 for some acceptable configurations Exit stairways that are part of accessible route in unsprinklered buildings must have 48” clear width between handrails Note: IBC requires ‘Areas of Refuge’ at floor landings inside rated stair assemblies for many building occupancies; these must not impede clear path of travel – usually placed to one side of accessible route


Protruding Objects

Restrictions on size, configuration of objects/building elements that project into corridors & walkways, because they present hazards for visually impaired


Detectable Warnings

Detectable warning surfaces are required on walking surfaces in front of stairs, hazardous vehicular areas, other areas where hazards exist without guardrails or other methods of warning Surfaces must consist of truncated domes as specified by ADAAG; currently only apply to boarding platforms in transportation facilities (on interior projects; this provision applies in many other places on exterior of buildings & outdoor facilities) Door handles required to have textured surfaces if door leads to area that may prove dangerous to blind person, such as doors to loading platforms, boiler rooms, stages


Signs and Alarms

Signage for visually impaired people must be provided that gives emergency information, other circulation directions Emergency warning systems required that provide visual and audible alarm Audible alarms must produce sound exceeding prevailing sound level in room by 15dB Visual alarms must be flashing lights, with frequency of 1 cycle per second ADA requires certain accessible rooms & features be clearly identified with accessibility symbol


Permanent Room Signage

Permanent rooms/spaces must be identified with signs with raised lettering 5/8”-2” high, depending on viewing distance; lettering must be uppercase, sans serif or simple serif, accompanied with Grade 2 braille Pictograms, if used, must be 6”h. min., must be accompanied by verbal description Signs must be eggshell matte or other nonglare finish, with characters/symbols contrasting background Permanent identification signs must be wall-mounted adjacent to latch side of door, with min. clear floor space 18x18” centered on characters, beyond arc of door swing Mounting height of baseline of lowest characters 48”min., 60”max. above floor


What is this

•International accessibility symbol required on parking spaces, passenger loading zones, accessible entrances, and toilet/bathing facilities where not all facilities accessible



•If fixed/built-in seating or tables provided in accessible public or common-use areas, at least 5%, but not less than one seating area must be accessible ˉIncludes nightclubs, bars, restaurants, etc. •In assembly areas with fixed seating, minimum number of wheelchair locations given in Table 18.1 ˉAt least 5% of fixed aisle seats must be aisle seats with no armrests on aisle side, or with removable/folding armrests on aisle side


Construction tolerances  and the ADA

•In order to avoid problems, accommodate imperfections in building construction, designer should do the following: ˉWhen ADAAG gives min-max. dimensions, designers should specify dimensions a little above or below the minimum and maximum dimensions, respectively.  Amount of allowance depends on construction elements, but ¼” to ½” usually sufficient ˉWhen dimensions given as a range, drawings should show midpoint of range or be well within range limits; should not show limits themselves ˉIf specific, single dimensions must be taken from accessibility guidelines and place in drawings, take extra care to highlight the fact that contractor MUST meet dimension exactly; usually done by making obvious note on drawings that emphasizes importance of meeting exact dimension