In this study an application is considered of the material accountancy principle to a subsystem of a tritium laboratory. The subsystem comprises the essential units of the so-called technical infrastructure, namely the transfer stations, the cleanup system, and the store; one experiment is representative of the “client.” The tritium transfers are batch wise. The accountancy effectiveness serves as a suitable yardstick which is evaluated under a variety of Doundary conditions typically encountered in operation of such a laboratory. Special interest is directed to the location of an assumed tritium anomaly. The analytical results are complemented by numerical examples.