This document specifies a test procedure, equipment and environment for evaluating the concentration loss of ultrafine bubbles (UFB) due to long-distance transfer of ultrafine bubble water in a plastic pipe. The test results are analysed and expressed in terms of a formula with the flow parameters, pipe length, flow velocity and number of circulations through the pipe. The formula is intended to be used for designing long-distance transport system for industrial applications including agro- and aqua- farming.