Question 20 OSE02 - Assistant Engineer - OSV

The Correct Answer is A. **Explanation for A (A high flash point solvent such as kerosene or diesel fuel):** Option A is correct because kerosene or diesel fuel are petroleum-based products derived from crude oil, making them acceptable as the manufacturer recommends a "petroleum-based solvent." Crucially, they possess a **high flash point**, meaning they do not easily ignite at room temperature or during normal cleaning operations. This high flash point makes them the safest choice for use in an engine room environment, minimizing fire risk associated with solvent cleaning. They are also effective at dissolving residual lube oil and sludge. **Explanation for Incorrect Options:** * **B) A low flash point solvent such as gasoline:** Gasoline (petrol) has an extremely low flash point, making it highly volatile and presenting a severe fire and explosion hazard in an engine room, even with adequate ventilation. Therefore, it is strictly avoided for industrial cleaning applications like this. * **C) A chlorinated solvent such as perchlorethylene or trichloroethylene:** While effective cleaners, chlorinated solvents are typically avoided in engine environments. When heated or used on hot metal parts, they can decompose and produce highly toxic and corrosive gases (like phosgene gas and hydrochloric acid), posing extreme health risks to personnel and potentially damaging equipment. They are also not specified as the recommended "petroleum-based" solvent. * **D) An aromatic solvent such as benzene or toluene:** Aromatic solvents like benzene are known carcinogens and pose serious long-term health hazards (toxicity). While toluene is less toxic, all powerful aromatic solvents require stringent handling and ventilation controls typically beyond what is practical or necessary for routine strainer cleaning. Furthermore, they often have lower flash points than kerosene and are less commonly used for simple degreasing where safety and cost-effectiveness are priorities.