Elevator (C-11) · Lesson 1 of 4

Hoistway Vent Area and Operation

"Hoistway Vent Area and Operation" is lesson 1 of 4 in the Elevator (C-11) Learning Hub. It opens with "Why a Hoistway Needs a Vent" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Why a Hoistway Needs a Vent
  2. Where the Vent Goes
  3. The Two Area Tests
  4. How the Vents Operate
  5. Reduced Area and Standby Power

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Hoistway area" through "Use the larger value".

What you'll be able to do

  • Explain the main idea of "Hoistway Vent Area and Operation" in plain language you can use on the exam.
  • Apply this step with confidence: "How the Vents Operate".
  • Apply this step with confidence: "Reduced Area and Standby Power".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
HOISTWAY VENT AREA2025 CBC 3003.4: vents at the top of the hoistway, sized by the larger of two tests(elevation, not to scale)to outer airVENT AT TOPCAR 1CAR 2CAR 3COMMON HOISTWAY 22 ft x 9 ft = 198 sq ftTHREE-CAR COMMON HOISTWAYTest A: 3 1/2 percent of hoistway area0.035 x 198 sq ft = 6.93 sq ftTest B: 3 sq ft for each elevator car3 cars x 3 sq ft = 9.0 sq ftLarger governs: 9.0 sq ft of vent areaSingle car check: 8 ft x 7 ft = 56 sq ft3.5% = 1.96 sq ft, so 3 sq ft governsVents open on smoke detected in hoistwayand on a manual override (opens and closes)Those detectors also start Phase I recallVent fan on standby power if elevators areon standby power (CBC 3003.1.5)RESULT: provide at least 9.0 sq ft of vent area at the top of the hoistwayThe 3 sq ft per car test governs because 3.5 percent of 198 sq ft is only 6.93 sq ftSource: 2025 CBC 3003.4.1 to 3003.4.4 (hoistway venting), 3003.1.5 (standby power), 3002.2 (cars per hoistway).The code prints "area of the hoistway"; the example takes it as plan area, width x depth.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Why a Hoistway Needs a Vent

An elevator hoistway is a tall, enclosed shaft, so in a fire it acts like a chimney for smoke and hot gases. The 2025 California Building Code (CBC) 3003.4 requires hoistways that contain the driving machine to have a means of venting smoke and hot gases to the outer air in case of fire.

Step 2: Where the Vent Goes

CBC 3003.4.1 locates the vents at the top of the hoistway. They must open either directly to the outer air or through noncombustible ducts to the outer air. A vent that discharges into the attic or a machine room does not satisfy this section.

Step 3: The Two Area Tests

CBC 3003.4.2 sets the vent area at not less than 3 1/2 percent of the area of the hoistway, and not less than 3 square feet for each elevator car. You run both tests and use the larger answer. Small single-car hoistways are usually governed by the 3 square feet per car, and wide multi-car hoistways by the percentage.

The remaining 2 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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