Bladder tanks, which consist of an outer metal tank with an inner elastomeric bladder, are commonly used to store and proportion foam concentrate in foam systems. Foam is stored inside the bladder while water is directed through piping to the area between the steel tank and the bladder. The resulting water pressure is used to force the foam out of the bladder and into a controller which then mixes the correct concentration of foam into the water.
Recognized standards recommend foam bladder tanks systems be inspected at least annually. Furthermore, the standards state an inspection for the presence of foam in the water surrounding the bladder. Foam concentrate in the water surrounding the bladder can be an indication of several severe problems:
- A tear in the bladder - foam concentrate can leak through the tear into the water surrounding the bladder. Even a small tear in the bladder can render the system inoperable.
- A missing isolation valve or an isolation valve that was not closed - the foam isolation valve prevents foam concentrate from siphoning through the controller and into the shell area.
- Improperly filling the bladder tank - for example, filling the shell area with foam instead of the elastomeric bladder.
Make sure to catch these issues by sending your bladder water to Dyne Fire Protection Labs. Dyne will run both physical and performance tests on the bladder water to determine if there is any presence of foam in the system.