Which of the following is NOT considered a flammable material?

Flammable materials are substances that can easily ignite and burn in the presence of an ignition source. Petrol, wood, and alcohol are all substances that catch fire relatively easily under the right conditions. Petrol and alcohol are both liquids that have low flash points, meaning they can ignite at lower temperatures, while wood is a solid that can ignite through combustion when exposed to heat.

On the other hand, steel is classified as a non-flammable material. It has a very high melting point and does not ignite or burn under normal conditions. It can withstand high temperatures without catching fire, which is why it is commonly used in construction and fire-resistant applications. Understanding the properties of materials in relation to their flammability is key to fire safety management and hazard prevention.