How many liters of oral special equipment to require certification

More than 30L. According to "TS212016 Fixed Pressure Vessel Safety Technology Supervision Regulations" and the 2016 "Special Equipment Catalog" shows that oral special equipment greater than or equal to 30L is required, less than 30L does not require a special equipment operating license. Special equipment refers to boilers, pressure vessels (including cylinders, the same below), pressure pipelines, elevators, cranes, passenger ropeways, large amusement rides and field (plant) dedicated motor vehicles involving life safety and greater danger.