Final answer:
The minimum volume of indoor combustion air required for a heater, as a guideline, is 50 cubic feet per 1000 BTU/hour, ensuring proper combustion for heating appliances.
Step-by-step explanation:
The question is regarding the minimum volume of indoor combustion air for a heater or furnace. This is calculated based on the BTU/hour rating of the heating appliance. According to the guidelines stated, a minimum of 50 cubic feet of air per 1000 BTU/hour is required to ensure adequate combustion. To provide an example, if a heater is rated at 30,000 BTU/hr, which is approximately 10 kW (as 1 BTU is roughly 1,055 Joules and one hour is 3,600 seconds, making one BTU/hr equivalent to 0.293 W), it would require a minimum of (30,000 / 1000) * 50 = 1,500 cubic feet of air per hour.