What safety measure should be taken when working with gas appliances?

Ensuring proper venting is crucial when working with gas appliances because it prevents the buildup of harmful gases, such as carbon monoxide, which can occur during the combustion process. Proper ventilation allows these potentially toxic gases to safely exit the space, minimizing the risk of poisoning and ensuring a safe environment for occupants. Venting systems are designed to direct these gases outside the building, and having an effective venting setup is an essential safety aspect of operating gas appliances.

In contrast, using metal piping, while sometimes advantageous, does not directly impact the safety related to gas combustion products. Lubricating joints with oil is generally not recommended for gas connections due to the risk of combustion; only specific types of sealants designed for gas should be used. Lastly, while flexible ducting can be useful in certain scenarios, it may not provide the necessary rigidity and integrity required for venting gas safely. Thus, ensuring proper venting stands out as the most critical safety measure in this context.