This document studies the reliability of instruments at the ISIS facility though data on lost time recorded by the facility. The causes and consequences of faults on scientific operations are examined. The use of beam-line shutter systems on instruments is examined as its
effectiveness to facilitate repair and mitigate the loss of availability on instrument. The report concludes that the incorporation of heavy shutter within the monolith of TS2
contributes significantly to availability of instruments and thus the scientific output of the facility. It is recommended that shutters with similar functionality are implemented at the ESS.