In terms of installation requirements, mechanical draft systems need to be?

Mechanical draft systems are crucial for ensuring safe and effective venting of combustion products from appliances. One of the primary installation requirements for these systems is that they must be listed for safety by recognized testing laboratories. This certification confirms that the system has been evaluated for safety, effectiveness, and compliance with established standards.

The necessity for these systems to be listed for safety stems from the potential hazards associated with improperly vented combustion gases, which can lead to carbon monoxide poisoning or fire hazards. Therefore, ensuring that a mechanical draft system is certified provides confidence that it meets the necessary safety protocols and operational performance.

While self-regulating features, environmental friendliness, and cost are certainly considerations in the overall selection and use of mechanical draft systems, they are not the core requirement that directly impacts safety and compliance. The pivotal aspect is the safety listing, as it ensures the product has undergone rigorous testing to support its effectiveness and safety in real-world applications.