Does a ventless kitchen hood still need IMC 507.3 in DC?

Short answer: Yes. A manufacturer's "ventless" listing addresses grease-laden vapor — the Type I side of the code — but it does not remove the IMC 507.3 heat and moisture obligation that governs Type II situations. A ventless oven is still a heat-producing appliance, and a steam cabinet is still a moisture-producing appliance.

Where the rule lives. IMC §507.3 sets the Type II hood installation requirements, the exception that lets a designer either fold the heat/moisture load into the HVAC design or provide a separate exhaust system, and the 0.70 cfm/sf hoodless alternative. This is all §507.3 body text — there is no sub-numbering (507.3.1–.3 are construction clauses). The entire §507.2 family is Type I (grease/smoke), so citing 507.2.2 for a Type II question is a common error. DC has not amended §507.3.

Three compliance paths.

1. Install a Type II hood.
2. Demonstrate the HVAC design carries the load — a written analysis showing the heat/moisture load is handled by the mechanical design. A ventless UL listing can support the oven side, but a steam cabinet's moisture load must be argued separately.
3. Hoodless alternative (0.70 cfm/sf). Provide whole-room exhaust at 0.70 cfm per square foot, counting each hoodless appliance at not less than 100 sf, so N appliances × 100 sf × 0.70 = minimum exhaust cfm (three appliances → at least 210 cfm). The designer then shows that existing exhaust covers this or adds capacity. This is often the least-cost route.