The entire floor area in a major repair garage without ventilation, up to a level of 18 inches above the floor, is considered a what location where Class I liquids, hydrogen, natural gas, or LPG are transferred?

The entire floor area in a major repair garage without ventilation, up to a level of 18 inches above the floor, is considered a what location where Class I liquids, hydrogen, natural gas, or LPG are transferred?

• A. Class II, Division 2
• B. Class I, Division 2
• C. Class II, Division 1
• D. Class I, Division 1

Answer: (B)

Hazardous-location classifications focus on whether flammable vapors or gases are present in the air during normal operation versus only under abnormal conditions. Class I covers flammable vapors and gases. Division 1 means ignitable concentrations are present under normal operation or are expected to occur as part of the process. Division 2 means ignitable concentrations are not normally present, but could occur because of abnormal conditions such as leaks, spills, or equipment failures, especially in areas with poor ventilation. In a major repair garage that has no ventilation, vapors from transferring Class I liquids (like gasoline, hydrogen, natural gas, or LPG) can accumulate near the floor. Since these vapors aren’t guaranteed to be present during normal operation but could appear due to leaks or spills in an unventilated space, the lower zone up to about 18 inches above the floor is classified as Class I, Division 2. The whole floor area within that 18-inch zone is treated as a Division 2 location to reflect the increased risk from potential abnormal vapor concentrations in a poorly ventilated area. Class II would apply to combustible dust, which isn’t the issue here, and Class I, Division 1 would be used if vapors were present under normal operating conditions, which isn’t indicated in this scenario.

Hazardous-location classifications focus on whether flammable vapors or gases are present in the air during normal operation versus only under abnormal conditions. Class I covers flammable vapors and gases. Division 1 means ignitable concentrations are present under normal operation or are expected to occur as part of the process. Division 2 means ignitable concentrations are not normally present, but could occur because of abnormal conditions such as leaks, spills, or equipment failures, especially in areas with poor ventilation.

In a major repair garage that has no ventilation, vapors from transferring Class I liquids (like gasoline, hydrogen, natural gas, or LPG) can accumulate near the floor. Since these vapors aren’t guaranteed to be present during normal operation but could appear due to leaks or spills in an unventilated space, the lower zone up to about 18 inches above the floor is classified as Class I, Division 2. The whole floor area within that 18-inch zone is treated as a Division 2 location to reflect the increased risk from potential abnormal vapor concentrations in a poorly ventilated area.

Class II would apply to combustible dust, which isn’t the issue here, and Class I, Division 1 would be used if vapors were present under normal operating conditions, which isn’t indicated in this scenario.