What type of weld must be used for all seams, joints, and penetrations of the hood enclosure that direct and capture grease-laden vapors and exhaust gases?

What type of weld must be used for all seams, joints, and penetrations of the hood enclosure that direct and capture grease-laden vapors and exhaust gases?

• A. Gas-tight seal
• B. Spot weld
• C. Butt weld
• D. Liquidtight continuous weld

Answer: (D)

The main idea is that the hood enclosure must be built with joints that are completely sealed against grease and vapors. Using a liquidtight continuous weld provides a seamless barrier along all seams, joints, and penetrations, so grease-laden vapors and any liquids used for cleaning can’t seep through gaps. This reduces the risk of grease accumulation, fire spread, and leaks into the duct or surrounding space, which is essential for safe kitchen ventilation and NFPA 96 compliance. Spot welds leave gaps that grease can penetrate; a plain butt weld isn’t guaranteed to be liquidtight along every joint; and a gas-tight seal isn’t required for this application. Continuous liquidtight welds specifically meet the need to keep the enclosure fully sealed under operational and cleaning conditions.

The main idea is that the hood enclosure must be built with joints that are completely sealed against grease and vapors. Using a liquidtight continuous weld provides a seamless barrier along all seams, joints, and penetrations, so grease-laden vapors and any liquids used for cleaning can’t seep through gaps. This reduces the risk of grease accumulation, fire spread, and leaks into the duct or surrounding space, which is essential for safe kitchen ventilation and NFPA 96 compliance. Spot welds leave gaps that grease can penetrate; a plain butt weld isn’t guaranteed to be liquidtight along every joint; and a gas-tight seal isn’t required for this application. Continuous liquidtight welds specifically meet the need to keep the enclosure fully sealed under operational and cleaning conditions.