Promat marine segment manager and naval architect Giorgio Lauro explains why thermal insulation is crucial for passenger and crew safety
Thermal insulation is of utmost importance on board ships for many reasons. Fire propagation, fire ignition and personnel-at-work protection are the most relevant.
SOLAS regulations provide strict guidelines with regards to thermal insulation on passenger ships with the intent to safeguard the life of passengers and crew. In particular, the regulations establish that ships shall be subdivided into spaces by thermal and structural divisions having regard to the fire risks of the space.
But another need for thermal insulation descends from the regulation on the probability of ignition of fire. That results in protecting high-temperature surfaces to avoid burnable liquid catching fire by accidentally hitting the surface (oil spills in the engineroom are reported to be one of the causes of fire inception). All surfaces with temperatures above 220°C which may be impinged as a result of a fuel system failure must be properly insulated.
The third need for thermal insulation is to protect personnel from burns on hot, exposed surfaces and this is also a top priority for ship safety. All it takes for skin to blister and burn is a few seconds of incidental contact with a hot surface. The administrations set a limit of a maximum skin temperature of 60°C after five seconds of exposure. By experience, no reportable injury will occur at this skin temperature and exposure time.
The external surfaces of ship’s piping, ductwork, engine exhaust and other equipment throughout a ship can reach temperatures well above 60°C. Systems with external surface temperatures greater than this threshold pose a major hazard to workers’ safety — so insulation is a must to mitigate burn potential.
Proper insulation for scrubbers
The recent application of scrubbers to be compliant with Marpol rules creates another potential hazard for the crew if proper insulation is not installed. The average temperature of the engine gases is above 600°C and the scrubbers are conveying the exhaust entering the funnel from all engines on board.
The average temperature in the internal part of the scrubbers ranges from 300°C to 450°C depending on the type of scrubber system cycle. Thermal insulation is needed to keep the external temperature on the scrubber surface below 60°C.
Belgium-based Promat, an Etex-group company, is stepping up its efforts to promote Microtherm Promaguard, a new generation product used for passive fire protection and thermal insulation, based on microporous technologies, as an option for use on board cruise ships and ferries. The company claims the material offers more reliable levels of protection, exceeding SOLAS fire protection standards, and significant weight and space savings, when used in bulkheads, decks, pipes and exhaust, including scrubber towers, compared with conventional solutions.
As an example, Promat solutions are capable of reducing the temperature of a duct or a scrubber tower from 450°C of internal temperature down to the required 60°C on the surface with only 45 to 50 mm of thickness.
Etex engineering department provides guidance and support to the customer, from concept and design, for selecting optimised solutions, taking into account all the parameters that can impact the thermal insulation performance, including ambient temperature and speed of the air flow in the machinery spaces.
A recent application of the Promat insulation system from Estonian company LTH Baas was striking: the company received an order from a cruise operator for a complete turnkey supply, starting from design of the new funnel, delivering all material and systems on the ship. Altering the existing structure to incorporate the scrubbers was carried out with the cruise ship fully operational with passengers on board, sailing in Asian seas. The order included reviewing naval architecture drawings and calculations to reach class approval until the final commissioning. The lightweight and thinner insulation provided by Promat benefited the overall project.