The testing and rating of terminals used on ventilation systems.

Terminals are used on all types of ventilation system exhausts, often to prevent rain water and animal entry, but also to prevent wind induced flow-reversal and enhance wind induced updraught. There are many different terminal designs available displaying a wide range of characteristics. This report discusses a terminal testing and rating method. The tests highlight terminal wind performance as well as terminal resistance to the exhaust flow. The terminals are ranked according to loss coefficients and wind performance which allows them to be matched more closely to system requirements. Whilst the data gathered here can help with the choice of terminal for any ventilation system, it is probably most applicable to those systems affected by the wind. Such systems include passive stack ventilation, passive gas extraction, combustion flues and chimneys. This paper is intended as a test guide for manufacturers and as source of information to help system designers with terminal selection.