Print this pageFirewater
Onshore and offshore firewater systems have similar problems, but each also has unique problems that need to be considered.
All firewater systems need to be designed carefully to ensure that the correct water distribution and volume is delivered. This is a well-understood procedure that requires modelling to correctly calculate the flow balance around the systems. This is normally quicker and cheaper when undertaken by specialist hydraulic companies.
Traditional design means that high velocities are accepted (because of the low erosion risk), but this can mean very high surge pressure potential.
Typically, pump risers drain whenever the pumps are not running. This will then cause dynamic forces and surge pressure problems when the pumps are started. Damage to welds and fitting is a common occurrence and inadvertent lifting of PSVs is a another major likelihood.
The high elevation changes on most offshore installation can cause the ringmain to drain as deluge areas start-up. This can cause air to be drawn in through any vents or can cause vapour pressure to form where no vents (sometimes also called ‘Vacuum Breakers’) are fitted.
Both air and vapour amplify surge pressures and so need careful analysis. High surge pressures have caused monitors and hydrants to be sheared from their fittings and can cause considerable pipe movement.
Performance standards now mean that careful planning and testing is required, but these tests can be misleading unless undertaken with a good knowledge of the underlying hydraulics and expected performance. We can provide the necessary modelling and support with interpreting test results. When problems are experienced our Performance Analysis service can help to quickly locate any bottlenecks.
We can provide the hydraulic modelling and surge analysis necessary to design and manage effective, trouble-free firewater systems. Our Performance Analysis and Condition Auditing services can then help to deliver the management processes needed to predict and locate any future problems.
