Where must high pressure steam safety valves be vented?

High pressure steam safety valves must be vented to the outside of the structure to ensure safety and prevent any dangerous buildup of steam or pressure within the building. Venting safety valves outside helps to safely disperse steam, which can be extremely hot and under high pressure, minimizing the risk of injury to occupants and reducing the chances of damaging the structure or its materials.

Proper venting is crucial in maintaining the integrity of the steam system and ensuring that any potential failures are managed effectively. If steam were to vent inside, it could lead to scalding, property damage, and potential health hazards due to the release of steam in enclosed spaces.

The other options do not provide a safe means of venting. For instance, venting into an internal drain may pose a risk of flooding or backflow. Directing steam to the front of the structure could lead to direct exposure to bystanders or occupants, while venting downward through the foundation could cause structural issues or create hazardous conditions in basements or crawl spaces. Therefore, venting to the outside is the most appropriate and safest practice as mandated by the mechanical code.