Roof and Wall Exhaust Path Explorer

Run the Roof and Wall Exhaust Path Explorer MicroSim Fullscreen

This p5.js sketch is built on the shared FanPedia MicroSim kit. To run it in the p5.js editor, add the kit files (fanpedia-sim.css, fanpedia-core.js, fanpedia-p5.js and fan-drawings.js from ../shared-libs/, or their published URLs) to the editor's index.html before pasting the sketch.

About This MicroSim

Roof and wall ventilation units differ mainly in the parts above the impeller: an open top, a motor cover, a hood, a louvered penthouse, a short stack or a wall mounting. Those parts decide where the exhaust air goes. This MicroSim shows seven units one at a time, in an order shuffled once per session, as schematic cutaways with the discharge hidden. You predict the path, then the sim draws the true path with arrows for the air entering and leaving the unit.

Unit	Path
Upblast centrifugal roof exhauster	Straight up
Downblast centrifugal roof exhauster	Up, then down and out
Hooded roof exhauster	Up, then down and out
Louvered roof exhauster	Up, then down and out
Low profile roof ventilator, upblast version	Straight up
Centrifugal wall exhauster	Straight out from the wall
Gravity relief ventilator	Up, then down and out

Each unit gets one attempt. A correct prediction reads "✓ Correct: ." followed by the reason; an incorrect one reads "✗ Not quite: this unit's air goes ." followed by the reason. The running score reads "Paths correct: n of 7". After the seventh unit a yes/no question asks whether a gravity relief ventilator needs a fan to move air. Mastery is 6 of 7 paths plus the gravity question, all on the first attempt.

Clicking a part of a cutaway (or choosing it in Read a part) shows its name and definition. That is exploration and is never scored. After the gravity question a summary table lists every unit, your prediction and the correct path, and the Review list reopens any unit's cutaway and path without changing the score.

How to Use

1. Study the cutaway. Click any part, or use Read a part, to read what it is.
2. Choose a path: Straight up, Up, then down and out or Straight out from the wall, then press Commit.
3. Read the feedback and watch the arrows: which part above the impeller set the path? Press Next unit.
4. After unit 7, answer the gravity question, then press Show summary.
5. Use Review to reopen any unit. Press Start over to clear the score and repeat the seven units in the same order.

Keyboard: keys 1–3 choose a path (1 = Yes and 2 = No for the gravity question) and move focus to Commit; Enter commits, then Enter goes to the next unit. Tab reaches every button and list; Enter or Space presses a focused button.

Data label: "Schematic cutaways, not to scale · Source: FanPedia pp. 5, 19, 181", shown at the bottom left of the drawing.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

<iframe src="https://moroshek.github.io/FanTASTIC-textbook/sims/ch05-roof-wall-exhaust-path-explorer/main.html"
        height="652px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Learning Objective

The learner will classify seven roof and wall ventilation configurations by the path the exhaust air takes as it leaves the unit, given a cutaway of each unit with its discharge hidden (Bloom: Understand, verb: classify).

Audience

Adult professional development: new application engineers, sales staff, representatives and facilities staff.

Duration

10–15 minutes

Prerequisites

• Upblast and downblast discharge
• Hooded and louvered roof exhausters, low profile roof ventilators
• Centrifugal wall exhausters and gravity relief ventilators
• Roof curb and gravity damper

All are covered in "On the Roof and Through the Wall" in Chapter 5.

Activities

1. Predict (8 min): For each unit, name the part above the impeller before you commit, and say which way it sends the air.
2. Check (2 min): Compare the drawn arrows with your prediction. Answer the gravity question by looking for the impeller.
3. Review (5 min): In the summary, reopen the hooded, louvered and downblast units side by side and note that three different covers give the same path.

Discussion Questions

1. Why would you never quote a downblast exhauster for kitchen exhaust, even though the air still leaves the building?
2. The low profile ventilator uses an axial propeller, the upblast exhauster a centrifugal wheel. Why do both send air straight up?
3. A supply fan runs and a gravity relief ventilator lets the air out. What moves the air through the relief unit?

Common Misconceptions Addressed

• Every roof exhauster blows air straight up: three of the roof units send it up, then down and out.
• A hood or louvers change the fan type inside the unit: the hooded and louvered units keep the same centrifugal wheel; only the path cover changes.
• Downblast units suit any exhaust because the air still leaves the building: the downblast feedback and the chapter warning show the air laid back onto the roof.
• A gravity relief ventilator contains a small fan: its cutaway has no impeller, and the gravity question asks about it directly.

Assessment

• First-attempt score shown as "Paths correct: n of 7"; mastery is 6 of 7 paths plus the gravity question, on first attempts.
• Reading part definitions and reviewing units in the summary are exploration and are not scored.
• Follow-up: ask learners to sketch the path for a roof unit they have seen and name the part that sets it.

References

1. Twin City Fan & Blower. FanPedia: The Fan & Blower Encyclopedia, p. 5 (centrifugal power roof ventilator airflow paths), p. 19 (roof exhauster exploded view), p. 181 (butterfly gravity dampers). PDF
2. Twin City Fan & Blower. FanPedia online - the same encyclopedia in web form.
3. Twin City Fan. Roof Ventilators product pages (LUD, LUB, LHD, LHB low profile units) - current models and impeller types.
4. Twin City Fan. Gravity Relief Ventilators product pages (GRV, MGR, TEL, MA) - relief and intake units with no fan.
5. Chapter 5: Roof, Wall and Specialty Exhaust Fans - the chapter this MicroSim supports.