Labor & Industries (L&I), Washington State

Machine Safety Chapter 296-806, WAC

Effective Date: 01/01/05

WAC 296-806 Helpful Tool: Calender Stopping Distances Chart

For printing

This tool will allow you to determine if your calender meets the emergency stopping distance required by the rule. The size or arrangement of the rolls doesn’t matter--they all have to stop within the specified limits unless there is no employee exposure to the hazard.

 

• You need to know the roll surface speed to use the chart. The roll surface speed is the distance (in feet) a point on the peripheral surface of the roll travels in one minute. You can determine the roll surface speed as follows:

Roll Surface Speed (feet per minute) = .262 x Roll Diameter (inches) x rpm

Examples:

• 24-inch diameter roll, 15 revolutions per minute.
  Roll surface speed = .262 X 24 X 15 = 94.32 feet per minute
• 12-inch diameter roll, 40 revolutions per minute.
  Roll surface speed = .262 X 12 X 40 = 125.76 feet per minute

Step 1:	Find the roll surface speed (in feet per minute) on the horizontal axis of the chart (on the bottom).
Step 2:	Draw a vertical line from the roll surface speed until it meets the sloped line between the shaded and un-shaded areas of the chart.
Step 3:	Draw a horizontal line from that point to the vertical axis (on the left side) and read the maximum acceptable stopping distance.
	Examples: A calender has a no-load roll surface speed of 125 feet per minute. The maximum stopping distance allowed is 26 1/2 inches A calender has a no-load roll surface speed of 100 feet per minute. The maximum stopping distance allowed is 21 inches.

Calender Stopping Distances Chart

The shaded area of the chart below shows acceptable stopping distances for calenders. These distances are measured:

• With the rolls running empty at maximum operating speed.
• In inches of roll surface traveled
• From the instant the emergency stopping device is activated.