Fire Protected Piping Systems
Plastic piping systems are generally used for both underground and above-ground fire protection systems. Knowledge of the fire reaction of the pipe material and the behaviour in the heart of a fire is an important factor in whether to specify composite pipes or not for above-ground applications. The most important applications where fire resistance plays an important role are: fire-extinguishing closed ring circuits, wet sprinkler systems, dry deluge systems and foam pipes.
Glass fibre reinforced piping systems are selected for the above-mentioned applications in particular because of their corrosion-free properties. Corrosion not only shortens the service life of these fire protection systems, but internal corrosion (commonly referred to as peeling) can also occur, which, under operational conditions, may block the spraying heads. From a safety perspective, the risk is unacceptable.
The fire behaviour of plastic piping is tested by independent bodies for many applications in the Marine (shipping), offshore platform and module (FPSO) sectors and industrial systems such as refineries, (petro)chemical complexes, storage facilities and tank terminals. There are also many applications in tunnels, ports and on jetties.
Plastics piping systems have an exceptionally favourable fire behaviour. The slow decomposition of the material creates a kind of insulation layer and a cooling effect also occurs on the outside of the pipe with what is commonly referred to as weeping. A combination of properties such as low thermal heat conductivity and slow decomposition of the pipe wall contributes to the exceptionally favourable fire behaviour. When the epoxy resin is finally burnt off, a ceramic carbon-containing layer remains that insulates the pipe, significantly delaying the burning process. The lifetime and fire resistance will depend on the actual heat flux of the fire and the type of fuel.
The operational conditions of the system are the determining factor for the lifetime:
- Pipe in dry condition.
- Pipe filled with water but without flow.
- Pipe filled with flowing water.