Cliff developed the CNP fit test method. He recently retired from the University of Arizona after a 26-year career in occupational and public health. Contact him at cdcrutch@comcast.net.
With the introduction of the controlled negative pressure (CNP) fit test method and the CNP
Redon fit test protocol, it is now possible to complete an OSHA-accepted fit test of a worker’s actual respirator in three minutes or less.