Electric smoke ventilation system is a key part of the building roof system. It's three important properties: waterproof performance, ventilation and smoke exhaust performance, and daylighting performance will obviously affect the convenience and cycle of the entire building. Among them, waterproof performance is the top priority.

If the smoke ventilation system has hidden water leakage and water leakage problems, it will have a greater impact on the owner's later production and operation, and even lead to suspension of production. There are many incidents in the industry that have caused serious troubles to the owners due to the unresolved water leakage problem of the roof smoke vent.

The performance of the smoke ventilator depends on the material selection and process technology. If the raw materials are standardized, the more critical is the manufacturing process and production technology. The most important thing is the waterproof method of the , automatic opening vent which can be divided into two types:

1. The traditional smoke ventilation system window sash uses a glue-like substance (usually silica gel) to bond the relevant gaps of the skylight window sash profile, and block water at the gap to prevent rainwater from entering the room through the gap.

2. Mcwell broke the conventional design concept of broken bridge aluminum and invented the "nail-free and glue-free waterproof structure" technology. This technology has been applied for patent in United States, Germany, Australia, Russia, etc. This technology uses the structure of the roof window sash profile itself to drain the water that enters the profile outside the window, which do not use a glue-like substance to bond any gaps to block water.