ADA Checklist for Emergency Shelters

E. Taking Measurements

1. Sloped Surfaces

Measuring the slope of a ramp, parking space, walkway, or other ground or floor surface is important to identify whether the surface is accessible. The amount of slope or grade is described as the proportion of a vertical rise to a horizontal length. It is usually described as:

• a ratio (e.g., 1:20, which means one unit of vertical rise for each 20 units of horizontal length); or

• a percentage (e.g., 8.33% which equates to a ratio of 1:12 or 4.76 degrees).

The easiest way to measure slope is to use a digital level. The digital display gives a reading that may be shown as a percent, degrees, or as a digital bubble. Before using a digital level, make sure to understand the directions for its use. It will need to be calibrated before each use. The maximum running slope generally allowed for ramps is 1:12 (8.33% or 4.76 degrees). Cross slope is the slope or grade of a surface perpendicular to the running slope. The most cross slope allowed on an accessible route is 1:50 (2% or 1.15 degrees).

Another way to measure slope that requires more effort is to use a 24-inch level with leveling bubble and a metal tape measure. Place the level on the sloped surface in the direction you wish to measure. Rest one end of the level at the highest point of the sloped surface and lift the other end (see below) until the bubble is in the middle of the tube. This is the “level” position. While the level is in this position, measure the distance between the end of the level and the sloped surface below. If the distance is two inches or less, then the slope is 1:12 or less. When the distance is more than two inches, record the distance on the checklist so the exact slope can be calculated later. For measuring cross slope, if the distance, measured from the level position, is ½ inch or less then the slope is 1:48 or less.

2. Using the Tape Measure

A metal tape measure is needed to measure the length, width, height, and depth of various elements. When measuring long distances, pull the tape tight to get an accurate measurement. The checklist will offer guidance for the specific measurement that is required.

3. Measuring Door Openings

Special care is needed when measuring the clear opening of a doorway. To measure the clear opening of a standard hinged door, open the door to 90 degrees. Place the end of the tape measure on the side of the door frame next to the clear opening (see below). Stretch the tape across the door opening to the face of the door. This measures the clear width of the door opening through which people pass, which is less than the width of the door itself.