One of the most common fire scenario for floating tanks is a rim fire and NFPA 11 standard requires foam chambers/pourers on the perimeter of the tank, which is effective but two weak points can be identified:
a. The rim fires, in the early stages, are relatively small and may be managed by a smaller water/foam application
b. The foam chamber system are often fed by the general tank-farm foam system, that is normally quite large.
This means : inertia, delay, damage to the rim and unnecessary waste of foam
In other words: a fire that may be extinguished by a small and quick system, causes a larger and slower system to go in operation. To address these negative points, RIMSEAL protection systems were introduced.
• “First strike” system is designed to extinguish small fires avoiding main foam discharge and rim damage;
• it must be SELF-STANDING (automatic operation without interaction with Control Systems);
• it must be EFFECTIVE on fire;
• it must be virtually MAINTENANCE FREE;
• …and it must be CHEAP.
Silvani Rimseal System
• Employs a pre-mixed AFFF foam solution contained in the vessel (AFFF is preferred to FFFP for fastest performance and solution lifetime).
• The tank is pressurized with Nitrogen to nominal 25 barg.
• Completely self-standing: the fire detection is made by specifically designed detection pipe, synthetic material, that bursts at a given temperature.
The pipe is UV resistant, chemical agent resistant, not subject to decomposition with time.
• The pressure loss causes the main valve to open.
• Designed to be gas tight for years under intermittent pressure condition (day-night).
• Modular design: a 250 litres vessel covers 40 metres rim circumference.