Abstract
A new type of personal sampling pump containing an electronic laminar-flow sensor was tested over two consecutive 30-day periods of normal use. Testing evaluated manufacturer claims that this flow sensor performs as an internal secondary standard, providing consistent flow and maintaining calibration within ±5 percent over a 30-day period without daily calibration. Data collected by two independent groups indicate that when subjected to typical use, this pump, which has a new type of flow control, provided a consistent flow rate and maintained calibration within the manufacturer's stated performance limits over a total of 63 days.