... Product Description Industrial fan,Centrifugal ventilator,Centrifugal fan,Ventilation fan,Exhaust fan,Ventilating fan,Standing fan,Exhaust fan: 1. Purposes: 4-72 type centrifugal fan as a general ... human body, not corrosive to steel gas. B4-72 fan can be as volatile flammable gas ventilation use. Gas is ... not more than 150 mg / m 3. B4-72 fan of the performance and selection of 4-72 and consistent ...