For a fuel-burning appliance installed in a confined space, what is the minimum area for each combustion-air opening for a 300,000 Btu/h appliance?

To determine the minimum area for each combustion-air opening for a fuel-burning appliance installed in a confined space, one starts by considering the National Fire Protection Association (NFPA) guidelines or similar building codes that address combustion air requirements.

For appliances that have a Btu input of 300,000 Btu/h, the calculation typically follows a guideline where the required combustion air is based on the input capacity of the appliance. Generally, the code states that for each 100,000 Btu/h of input, a minimum of 50 square inches of combustion air opening is required.

Therefore, for a 300,000 Btu/h appliance, you would calculate it as follows:

300,000 Btu/h divided by 100,000 Btu/h equals 3. Then, multiply by 50 square inches to find the minimum required area:

3 x 50 square inches = 150 square inches.

Thus, for this specific scenario, since it is asking for the area per opening, it is typically considered as half of the total area. Therefore, the minimum area for each opening becomes 150 square inches divided by 2 which gives you 75 square inches per opening. However, codes can vary, hence the selection