To prevent this situation, a fusible plug should be installed. All installed and ready for operation couplings must be fitted with at least one fusible plug, according to the National Regulation. Each coupling is attached with 2 to 4 fusible plugs depending on its size. The housing of the plug could be manufactured from stainlesss tell or brass. Different manufacturers may have different plugs in appearance. Event hough the shapesare different, fusible plugs can be replaced as longas the flow pointand tooth temperature checks. Yield Temperatures 110°C (Binding Platform - Water) and 140°C (Binding Platform - Oil). 160°C and 180°C are less common. Some companies top- dye over the plugs to indicate the different yield temperature. For example; Yellow for 110°C, Red for 140°C, Green for 160°C, Blue for 180°C.