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Storm Drainage Systems Flashcards

7 cards from real IPC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Storm Drainage Systems flashcards as text

  1. Per the IPC, what is the minimum allowable size for a roof drain?

    Answer: 3 inches

    The IPC specifies that roof drains shall not be less than 3 inches in size, regardless of the calculated drainage area.

  2. Under the IPC, horizontal storm drainage piping larger than 3 inches in diameter must have a minimum slope of:

    Answer: 1/8 inch per foot

    Horizontal storm drain pipes larger than 3 inches in diameter require a minimum slope of 1/8 inch per foot, less than the 1/4 inch required for smaller pipes.

  3. According to the IPC, are combined sanitary and storm drainage systems permitted in new construction?

    Answer: No, except where specifically approved by the administrative authority

    The IPC prohibits combined sanitary and storm drainage systems in new construction unless the administrative authority specifically approves it, such as where the public system is combined.

  4. Per the IPC, subsoil (foundation) drainage systems must discharge to:

    Answer: An approved location such as a storm drain, combined sewer (where approved), or daylight

    Subsoil drain systems must discharge to an approved location, which can include a storm drain or an approved point of disposal such as daylight — not into the sanitary system.

  5. When sizing a storm drainage system under the IPC, which of the following factors is NOT used to calculate drain pipe sizes?

    Answer: Soil percolation rate

    Storm drain sizing uses rainfall intensity, drainage area, and pipe slope; soil percolation rate applies to subsurface absorption systems like septic fields, not storm drains.

  6. Under the IPC, when a roof has expansion joints, roof drains must be installed:

    Answer: On each side of every expansion joint

    Because water cannot flow across an expansion joint to reach a single drain, the IPC requires roof drains to be placed on each side of the joint.

  7. Per the IPC, a trap is required on a storm drain conductor when it connects to:

    Answer: A combined sanitary and storm sewer

    When a conductor connects to a combined sewer carrying sanitary waste, a trap is required to block sewer gases from rising back through the storm drainage system into the building.