Seams, joints, and penetrations of the hood shall be permitted to be ______, provided that the weld is formed smooth or ground smooth, so as to not trap grease, and is cleanable.

• A. Internally welded
• B. Externally welded
• C. Soldered
• D. Riveted

Answer: (A)

The key idea is the cleanability of hood seams and joints. In kitchen hoods, every seam, joint, and penetration must be designed so grease cannot trap in crevices and so the surface can be kept clean. Allowing the seam to be formed by welding on the inside of the hood, with the weld ground smooth, achieves this by keeping exterior surfaces flush and free of raised weld beads. Internal welding prevents exterior grooves where grease could accumulate and makes cleaning straightforward, which is essential for fire safety.

External welds would leave visible weld beads on the outside that can trap grease and be harder to clean. Soldered joints and riveted joints either don’t provide the same durability under high heat and cleaning chemicals or leave gaps and crevices that grease can collect. So, internal welding that is ground smooth is the permitted and preferred approach.