With the increasing awareness of energy conservation and environmental protection, many steel structure factories have chosen to install natural ventilator, smoke vent rooflight, and other ventilation equipment for air ventilation. But the problem is that many clients don't know how to solve water leakage problem. In the early steel structure workshops, natural vent is used for air ventilation. At that time, natural ventilators and ventilated buildings were the mainstream products for factories. And the roof waterproofing of the factories generally use silica gel waterproof technology, when installing smoke vent rooflight, there will be a lot of self-tapping screws, which will cause water leak into the smoke hatch skylight. Although silica gel can elimanate leakage, it only solve the problem temporarily.