A building official is inspecting the installation of a standpipe system in a new 10-story office building (Group B). The building has a total height of 120 feet (36.6 m) above grade plane. What class of standpipe system is required for this building, according to IBC?
- AClass II
- BCombination of Class I and Class II
- CClass III
- DClass I
Show answer & explanationAnswer & explanation
Correct answer: C. Class III
According to IBC Section 905.3.1, Class III standpipe systems are required in buildings where any of the following conditions exist: (1) more than three stories above or below grade plane, or (2) the highest floor is located more than 30 feet (9144 mm) above the lowest level of fire department vehicle access, or (3) the lowest floor is located more than 30 feet (9144 mm) below the highest level of fire department vehicle access. A 10-story building clearly exceeds the 'more than three stories' threshold, thus requiring a Class III system.
Why the other options are wrong
- A. Class II systems are for occupant use, but a Class III system is required due to height.
- B. While a Class III system is a combination of Class I and Class II features, the answer refers to the specific class required by code for this building type and height.
- D. Class I systems are for fire department use only, but a Class III system is required here due to height.
Standpipe System Classes
Standpipe systems are categorized into classes (I, II, III) based on their intended users and the building's characteristics.
- Class I: Fire department use only (2.5-inch hose connection).
- Class II: Occupant use (1.5-inch hose connection).
- Class III: Both fire department and occupant use (1.5-inch and 2.5-inch connections).
Memory trick: Standpipe class: Height, stories, and who's the hero.