Master Electrician Practice Exam

In an aircraft hangar, how high does the area classified as a Class I, Division 2 or Zone 2 location extend above the upper surface of aircraft wings?

1. 3 feet

2. 5 feet

3. 7 feet

4. 10 feet

The correct answer is: 5 feet

In aircraft hangars, areas classified as Class I, Division 2 or Zone 2 are associated with the potential presence of flammable gases or vapors. The height of these classified areas is important for ensuring safety measures are in place to prevent ignition sources from contacting flammable substances. In this context, the height classification for such areas typically extends 5 feet above the upper surface of aircraft wings. This standard is based on safety regulations that take into account the likelihood of flammable vapors being present and the operational requirements of aircraft. Beyond 5 feet, it is generally considered that the risk is significantly reduced due to dispersion of any flammable vapors. This understanding is aligned with industry safety standards and helps determine the necessary precautions, such as electrical equipment ratings and other safety systems, in order to protect both the aircraft and personnel within the hangar.