What should uninsulated single-wall pipe NOT be used for in cold climates?

Uninsulated single-wall pipe should not be used for venting gas appliances outdoors in cold climates because it lacks sufficient insulation to prevent the potential for condensation and freezing within the pipe. In colder temperatures, the gases vented through uninsulated pipes can cool rapidly, leading to moisture condensing on the interior surfaces. This condensation can cause problems such as corrosion, blockages, or even the formation of ice, which may obstruct the venting system and create dangerous situations such as gas buildup or back drafting.

In contrast, indoor venting of gas appliances and heating indoor spaces are managed under different conditions that are less likely to encounter freezing temperatures, making the use of uninsulated pipe more acceptable in those situations. The storage of gas containers relates more to safety and regulatory compliance rather than the venting conditions of a pipe, which is why it is also not directly impacted by the cold climate factor as related to the venting of gas appliances outdoors.