Final answer:
Gas appliances must be located to allow for proper air circulation for combustion and ventilation to prevent incomplete burning and carbon monoxide production. Entrainment devices, such as Bunsen burners and water heater chimneys, help facilitate this and need to be unobstructed.
Step-by-step explanation:
Gas appliances should be installed in a way that they do not interfere with the proper circulation of air for combustion and ventilation purposes. This is crucial because gas appliances rely on an adequate air supply for efficient and safe operation. The combustion process in gas appliances, where natural gas is often used for space heating, water heating, and cooking, requires a specific amount of oxygen to ensure complete and clean burning of the gas. Incomplete combustion due to poor air circulation can lead to the production of carbon monoxide, which is a dangerous, potentially lethal gas. This remains a serious concern, as this reaction is responsible for dozens of deaths each year from unventilated or improperly adjusted gas heaters.
Examples of entrainment devices that promote proper air circulation by creating low pressures to entrain air, include Bunsen burners and water heater chimneys. Ensuring that these devices, especially the chimney of a water heater, are not obstructed is essential for maintaining proper airflow and preventing hazardous conditions. Additionally, this requirement is part of broader measures aimed at preventing the risks associated with fuel combustion in enclosed spaces, which is a concern with appliances running on various fuels including natural gas, kerosene, and wood.