Home Builders Institute Pre-Apprenticeship Certificate Training (HBI-PACT) Practice Test

Which of the following is considered a combustible metal?

1. Aluminum

2. Steel

3. Copper

4. Titanium

The correct answer is: Aluminum

Aluminum is considered a combustible metal due to its ability to ignite and burn fiercely under certain conditions, especially when finely divided into dust or powder form. This characteristic is primarily attributed to aluminum’s high surface area in those forms, which increases its reactivity with oxygen, promoting combustion. In industrial settings, aluminum is often used in various applications, but when handling or processing it, particularly in powdered form, appropriate safety measures must be taken to prevent fires or explosions. Steel, copper, and titanium can also have combustion-related hazards, but they do not possess the same inherent properties of combustibility as aluminum. For instance, while certain high-temperature conditions can lead to the ignition of titanium, it does not ignite as readily as aluminum. Steel, being an iron alloy, is generally non-combustible, and copper, while it can oxidize at high temperatures, does not burn in the same way that aluminum can. Understanding the properties of these metals is critical for ensuring safe handling in construction and manufacturing environments.