In terms of safety, what must be ensured when connecting gas appliances?

Ensuring that connections are airtight is crucial for the safe operation of gas appliances. An airtight connection prevents gas leaks that could lead to dangerous situations, such as explosions or asphyxiation from carbon monoxide poisoning. Gas leaks can occur if the joints or fittings are not tightly sealed, which is why using appropriate sealants and ensuring proper installation techniques is paramount.

While the visual appeal of seals and ensuring that fittings match the brand can be important for overall quality and compatibility, they do not directly relate to the safety of the appliance. The requirement that only certified technicians should install is also important for ensuring proper installation and compliance with safety standards, but the most immediate concern in terms of safety when connecting gas appliances is achieving an airtight connection to prevent gas leaks.