Initial kitchen hood airflow
Use this kitchen exhaust hood airflow calculator to make an initial capture-airflow estimate for an assumed hood arrangement. It brings hood dimensions, capture distance, capture velocity and cooking duty into one transparent calculation. Calculate without an account and use the result as a starting point for coordination, not as a certified capture or containment performance. Actual appliances, heat release, grease production and the surrounding room airflow still require assessment.
Existing capture-velocity formula
Enter hood length and width in metres, distance to hood in metres, capture velocity in m/s, hood type and cooking duty. The existing engine calculates Q = 1.4 × V × 2(L + W) × H × F, in m³/s. Light Cooking uses factor F = 0.7 and Heavy Cooking uses F = 1. A wall-mounted hood applies an additional 0.75 multiplier to the island-hood calculation.
Worked example: an island hood
Assume a hood length of 2 m, width of 1 m, capture distance of 1 m and capture velocity of 0.3 m/s. Select Island and Light Cooking, so the assumed duty factor is 0.7. The result is 1.4 × 0.3 × 2(2 + 1) × 1 × 0.7 = 1.764 m³/s. Multiply by 3,600 to obtain 6,350.4 m³/h of estimated exhaust airflow.
Make-up air and fan discussion
If make-up air is enabled at an assumed 80% of exhaust, the same example requests 1.4112 m³/s, or 5,080.32 m³/h, of replacement air. This percentage is illustrative, not a prescribed kitchen balance. Determine where replacement air enters and whether its temperature and movement disrupt capture. The engine’s fan type suggestion is only preliminary; select a fan using the required duty point and the manufacturer’s certified performance curve.
Pressure and capture limitations
Airflow alone cannot determine the installed fan. Prepare a pressure budget for the actual duct route, fittings, grease filters, treatment units, discharge and other components. Optional pressure estimates depend on the entered lengths and loss assumptions and must be checked against real product data. This simplified perimeter model does not simulate thermal plumes, cross-draughts or a manufacturer-tested hood. Review fire safety, cleaning access, discharge location and noise with the project team.
Singapore project review
Treat this output as a draft for review, not a stamped design or an approval. For a Singapore submission, check the applicable SS553 requirements and the project specification with the responsible designer. Verify the input schedule, record the assumptions, and reconcile the calculation with drawings and manufacturer data. This tool does not identify every applicable requirement, certify compliance, or replace professional judgement about installation, operation, safety, and maintenance. Retain the calculation date and revision so later changes can be traced to their original assumptions.