What are the key factors to consider when choosing a man-proof ventilation casing?

What are the key factors to consider when choosing a man-proof ventilation casing?
Many friends do not know much about manned ventilation casing, it is easy to be fooled when buying manned ventilation casing, and in the face of the wide variety of manned ventilation casing market is also easy to confuse, sometimes see this feel very much like, see that and feel very good, choose to choose do not know which to choose, in fact, we buy manned ventilation casing, should first determine a good budget in advance, is to buy good material according to the working conditions In fact, we should first determine the budget in advance, is to buy a good material according to the working conditions, the choice of man-made ventilation casing on the target. So what are the key factors to consider when we buy manned ventilation casing? Summarize 3 points can be prioritized, read it and understand.
Ventilation man-proof casing - that is, the environment in which the casing is used to prevent liquid leakage or leaks (such as pools, septic tanks, basements, etc.). The casing is poured into the wall as a whole, and no cracks or leaks will occur due to expansion and contraction factors. The working principle of the man-proof ventilation casing: It is suitable for the structure (construction) building where the pipeline goes through the wall and does not bear the vibration and expansion of the pipeline. Human defense ventilation closure casing is a special ventilation closure casing for human defense basement. Manproof ventilation closed casing is 2-4cm thicker than the pipe, fixed on the wall or plate, the pipeline through. One is to fix and prevent loosening, preferably combined with concrete; the other is to prevent infiltration along the pipe wall or casing wall into the protection area, so there are standard requirements for the material, thickness and height of the ventilation closure casing. The selection can be made with reference to the following:
1 . Select the material for the construction of the reserved hole. According to the diameter of the pipe, make a diameter than the diameter of the pipe 2 steel casing, and make a windproof ventilation closed casing. The length of the steel casing is usually the floor thickness + 300mm. laying civil floor template, tying the bottom steel, human defense ventilation closed casing, according to the specification requirements and the size of the steel tying forming site, determine the location of the human defense ventilation closed casing, the steel casing placed in the reserved location, and steel wire tied steel sleeve nailed to the template, steel sleeve firmly fixed on the template, no gap between the bottom of the steel sleeve and the template.
2 . After pre-burying, the filler should also be put into the man-proof ventilation closure casing to fill the casing and prevent the concrete from entering the casing when pouring. The materials, finished products, semi-finished products, accessories and equipment used in the construction of man-proof casing have Chinese quality certificates, and their specifications, models and performance test reports should meet the national technical standards or design requirements. The airproof casing should be level and the pipe should be straight. When inclined, laid from low to high, the socket should face the high direction; Waterproof casing inspection: check whether the socket position meets the requirements.