# LDD-07 · Cooking + Island Ventilation System

> **Status:** 🔴 LOCKED design intent — performance risk requires hood specialist before signoff.

## One-line intent

A high-performance cooking environment using induction + removable griddle/BBQ plates, an air-curtain plume containment plane, an oversized recessed ceiling capture field, a remote quiet exhaust blower, and a diffused luminous light panel disguising the mechanical function — all instead of a hanging hood.

## Why this matters

This is the single most ambitious piece of the project and the **highest-performance-risk** item in the LDD set. The visual goal is correct (no big hanging hood over an island in the middle of an open living space); the engineering bar to actually achieve it for Korean BBQ-grade smoke is higher than the LDD currently acknowledges.

## Locked decisions

**Island cooking layout**

| Zone | System | Use |
|---|---|---|
| Center (slightly cook-biased) | Bridge-zone induction | Removable flat griddle plate · Korean BBQ-style grill plate · teppanyaki · burgers · pancakes |
| East | Traditional 4-burner induction | Pots, pans, boiling, sauces, everyday tasks |

**Ventilation strategy**

- **Not** a conventional hanging hood.
- High-mounted recessed ceiling capture field + air-curtain assist + natural plume rise + remote blower.

**Air curtain**

- Linear slot integrated at the cook-side / guest-side boundary
- Creates upward containment plane (not exhaust itself)
- Biases plume upward into ceiling capture
- Tunable fan output; gentle controlled airflow
- Too weak = ineffective; too strong = turbulent and counterproductive

**Ceiling capture field**

- Centered over island, integrated into ceiling plane
- **Mounting height LOCKED at 8' AFF** (per builder)
- With cooktop at ~3'-6" AFF, this gives **~4'-6" clearance above the cooking surface** — generous compared to a typical 30" residential hood-to-cooktop gap, while still well within reach of an oversized recessed capture field
- Capture field **larger than cooktop footprint**: +18–24" preferred

**Ceiling feature — vent + light hybrid**

- Continuous perimeter slot intake (~1"–2", subject to engineering)
- Central diffused luminous light panel (2700K–3000K, 90+ CRI, dimmable, no visible LEDs)
- Slight recess (~1"–3") for glare control
- Removable/serviceable panel preferred

**Exhaust system**

- Remote inline or exterior-mounted blower near east wall
- Adequate CFM for high-smoke mode
- Speed control / multiple modes
- Make-up air considered if required by code or system CFM
- Grease management included
- Service access included

## Open items / requires engineer review (large)

- **Required CFM** for the 8' vs 9' AFF capture target — needs hood specialist.
- **Perimeter slot intake sizing** at the target CFM.
- **Air curtain slot velocity** to contain plume without turbulence.
- **Make-up air requirement** — at high CFM (likely 800–1,500+ CFM for Korean BBQ + 4-burner combined), make-up air is mandatory in most jurisdictions.
- **Grease filtration** and cleaning regimen.
- **Acoustic performance** of the remote blower (the whole point of putting it remote is quiet operation — verify in spec).
- **Interaction with HVAC supply air** in the living wing — diffusers near the island can disrupt plume containment.
- **Interaction with ceiling fans / destratification fans** in adjacent gym.
- **Service access** for light panel, plenum, filters, and remote fan components.

## Cross-references

- → [LDD-06 living wing HVAC](06-living-wing-hvac.md) — make-up air and trunk coordination.
- → [LDD-12 ceilings](12-exposed-ceilings.md) — capture field is the highest-stake exception to "no soffit" rule; the recessed plenum must read as architectural feature, not soffit.
- → [LDD-20 social counter](20-social-counter.md) — cooking layout integration with the island.
- → [LDD-08 lighting](08-lighting-framework.md) — central light panel is part of the lighting system, scene-controlled.

## Cost drivers

- **Custom recessed ceiling capture field + plenum**: $15–30K. This is not an off-the-shelf product.
- **Air curtain hardware** (linear slot with tunable blower): $3–8K.
- **Remote inline blower** (sized for ~1,200 CFM with quiet operation): $4–9K + ducting $3–6K = **$7–15K**.
- **Make-up air system** (passive vs active; tempered MUA recommended in cold climate): $3–12K depending on tempering.
- **Diffused light panel** (custom-fab to integrate with capture field): $2–6K.
- **Induction cooktop + bridge-zone unit + removable plates**: $6–14K (Wolf, Miele, or similar; griddle + Korean BBQ removable plates $400–1,200 ea).
- **Engineering / consultant fee** (hood specialist): $3–8K.

**Likely-case rollup: $50–100K for the cooking + ventilation system**, with skew toward the high end because of the custom integration.

> [LDD-FINISH-01 (flooring)](24-flooring.md) does not affect the ventilation system, but does affect the floor under the social counter — note the SPC LVP must allow for any island plumbing/electrical penetrations.

## Air-gap concerns

This LDD has the most concentrated technical risk in the set. Treating them as a numbered list because each is real:

1. **Korean BBQ generates serious grease aerosol, not just smoke.** A bench-style Korean BBQ session can put 15–30 g of grease aerosol per hour into the room air. Recessed ceiling capture fields work well for low-velocity heat plumes; they perform less well for grease-laden cooking effluent which wants to condense and drip. Plan for **grease catchment** inside the plenum (drip pan, sloped floor, cleaning access) — not just filters.
2. **Air-curtain containment is a 5–10% performance trick, not 50%.** Real-world air curtains in commercial kitchens help capture efficiency in the single-digit percentage range. The LDD implies the air curtain is doing more lifting than it can. Treat it as helpful, not load-bearing.
3. **8' AFF capture height is reasonable, with caveats.** *Updated per builder.* At 8' AFF over a 3'-6" cooktop, the capture face sits 4'-6" above the cooking surface — substantially farther than a typical 30" residential hood, but the recessed capture **field** is much larger than a hood face. Net capture efficiency for high-smoke cooking is plausibly in the 65–80% range with a properly tuned system, vs. 90%+ for a close-mounted commercial hood. For Korean BBQ specifically, this is the design's most engineering-sensitive bet — the air-curtain assist + oversized field + remote blower combination needs real CFM design, not just intent.
4. **No mention of grease classification.** Code may classify Korean BBQ as Type I (grease) appliance, which would trigger requirements for grease ducts, fire suppression (Ansul), and inspections normally reserved for restaurants. Verify with local AHJ. This could meaningfully change the design.
5. **Make-up air at 1,200+ CFM in a tight envelope is a major design item.** Tempered MUA preheats incoming air to avoid 0°F gusts when the vent runs. Without tempering, kitchen feels miserable in winter. With tempering, MUA system can cost $6–12K and adds complexity.
6. **Performance failure mode is invisible until move-in.** If the system underperforms, the open living space fills with smoke during Korean BBQ. By then walls are closed. **Therefore: build a mockup or rent a similar setup and test before signoff.** This is the single best risk-reduction move you can make.
7. **Service access for filters/plenum in an integrated ceiling feature.** The LDD says "removable/serviceable panel preferred" — make sure preferred means specified. Cleaning the inside of a recessed grease plenum is unpleasant; designing for it now is worth a lot.

## Diagram

![Island cooking section: air curtain, plume, capture field with perimeter slot + center light panel, remote blower](../../diagrams/11-island-cooking-section.svg)

## Status

🔴 **Red — design intent locked, but performance must be proven before signing the integration.** Engage a hood specialist. Build a CFM mockup if at all possible. The visual ambition is achievable; the engineering will determine if it works.