What type of vent is required when the vent of a wall furnace is concealed in a partition wall?

When a wall furnace vent is concealed within a partition wall, a BW vent is required. BW vents are specifically designed for use in applications where the venting system may not be visible, allowing for installations within walls. This type of venting is constructed to handle the high temperatures and potentially aggressive combustion products that result from the operation of gas appliances, ensuring both safety and effective performance.

In scenarios where the vent is enclosed, it's critical to use components that maintain appropriate service and clearance requirements, which BW vents fulfill. They also comply with building codes for venting gas appliances in concealed spaces, promoting both safety and efficiency.

In contrast, other types of vents such as B vent, L vent, and BH vent have specific uses that do not apply to concealed installations. B vents are typically used for natural draft appliances, L vents are designed for a particular application where direct venting is involved, and BH vents cater to specific high-efficiency appliances with different installation requirements. Each of these choices serves a distinct purpose and may not provide the necessary protections and performance for concealed vent installations.