How do I perform a Wipe Test using the Ranger and Wipe Test Plate? Posted on April 18, 2018May 7, 2018 A swipe or smear, such as cotton twill or flocked style swipes, should be used. An area of about 100 cm2 should be wiped with the swipe. The filter paper is then placed on the Wipe Test Plate and slid over the back of the Ranger. It is necessary to establish a background level first. To do this, follow the above procedure with an unused filter paper using the timed count feature of the Ranger for a period no less than 10 minutes. The actual amount of contamination is the difference between the count rate of the wipe test and the background count rate. An area should be cleaned if the counts are greater than twice the background wipe test. Save the Wipe Test data sheet. When numerous wipes are being taken, such as when a complete lab survey is being performed, locations of wipes should be recorded on a lab diagram. If one or more wipes reveals contamination, the location of the contamination can then be determined. Note: Be careful to place the swipe flat on the wipe test plate so that it does not come in contact with the Ranger and potentially contaminate the unit. The Wipe Test Plate, which has an electro-polished finish, can be cleaned, whereas the detector itself cannot.