Measuring, monitoring and controlling the many fluids that are part and parcel of daily operation on a ship is not a trivial task in shore-based installations, but when the plant is at sea, a host of other specialized considerations need to be taken into account.
For example, a ship’s energy management system that is not functioning optimally will affect energy efficiency and counteract the owner’s efforts to run a sustainable operation. Even more importantly, dangerous pressure levels, particularly in safety critical systems such as fuel supply tanks and lines, can endanger passengers and crew.
Instrumentation is therefore vital to keep a check on these parameters and processes. Common uses for marine instruments include controlling alarm and power systems, managing the level of engine fluid, fuel and oil and maintaining the correct level of ballast fluid.
However, the challenging environment at sea throws up some unique conditions that seaborne instrumentation must handle. These can include extremes of temperature and humidity, the ever-present risk of salt and its corrosive effects and the fact that a moving ship means that measuring instruments must work as effectively in rough seas and inclined at angles away from the vertical.
Ensuring that instruments conform to these requirements is the role of certification bodies such as DNV, OIML and IMO. For example, DNV specifies that instruments must withstand a salt-contaminated atmosphere up to 1 mg salt per m3 of air and a relative humidity of 100% for some temperature classes. Other specified conditions include acceleration, explosive atmospheres, temperature shock, wind, rain, snow, ice, dust and mechanical shock or bump forces equivalent to 20 g of 10 ms duration.