A foam chamber of a fire suppressant system having a closable testing outlet is disclosed. The foam chamber can operate in a testing mode and an operation mode. The invention has an inlet conduit for accepting a fire suppressant fluid attached to an expansion conduit. An expansion enclosure having two closable outlets is also attached to the inlet conduit and surrounds the expansion conduit. One outlet empties into the expansion enclosure. The other outlet extends through the wall of the expansion enclosure and empties outside of the expansion enclosure. Both of the closable outlets can be fitted with either an unbreakable seal or a frangible seal. If the foam chamber is configured for normal operation, the unbreakable seal is placed on the outlet that extends through the wall of the expansion enclosure and a frangible seal is placed on the outlet that empties into the expansion enclosure.