Dimensional Tolerances in Construction and for Surface Accessibility

Current industry standard practices resulting from this project

Interlocking Concrete Pavement Institute (ICPI)
The ICPI, along with the Brick Industry Association and the National Concrete Masonry Association, funded research in 2002 to evaluate the vibration exposure during electric and manual wheelchair propulsion over several types of sidewalk surfaces. Studies were repeated in 2003 and 2004 to determine the effects of environmental factors and evaluate additional surface types. The research was conducted by the University of Pittsburgh Human Engineering Research Laboratory and was based on exposure limits of vibration to the human body established in ISO 2631, Evaluation of Human Exposure to Whole - Body Vibration.

Based on this research, it was determined that some types of pavers (both square edged and beveled) and installation methods were an acceptable type of exterior paving. With the encouragement of the Access Board project, ICPI developed recommendations for segmental concrete pavement and installation tolerances based on the research they funded. 

Refer to the ICPI document in Part 3 for the detailed recommendations and construction tolerances that were developed.

Brick Industry Association (BIA)
The BIA participated in the funding of the research conducted at the University of Pittsburgh and two brick paving patterns were tested along with the concrete pavers. The BIA agreed to develop surface tolerances as part of the Access Board project. These are currently under development.

Tile Council of North America (TCNA)
The TCNA participated in this project and developed guidelines for ramp slopes, changes in level, flatness and lippage. These were published in the 2009 edition of the TCA Handbook for Ceramic Tile Installation. Refer to the TCNA document in Part 3 for the full text of the guidelines.