Conditions under which inspection holes need not be provided on containers
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Article 46 of the regulations specifies the conditions under which containers do not need to have inspection holes. Regarding Article 3, what is everyone’s understanding of containers with minor corrosion that do not require internal inspection or cleaning? For a 150L air tank with a design pressure of 1MPa and made of 16MnR material, equipped with connections for air inlet, air outlet, pressure gauge, safety valve, drain pipe, etc., is it possible to do without an inspection hole?
Personally, I think it’s not necessary to include inspection holes; since air alone is sufficient and no cleaning is required, having a drain pipe is enough
It’s hard to say regarding this issue; it’s a rather ambiguous one. However, for a small air tank of 150L, if its diameter is 300mm or less, there is no need to provide an inspection hole. If the diameter is large, the purity of the air and its moisture content also need to be considered in order to determine the degree of corrosion; if the corrosion is mild, no inspection holes will be created.
I agree with the person on the 3rd floor; I disagree with the person on the 2nd floor. Air does cause significant corrosion, so one should not assume that air alone leads to only minor corrosion and thus skip installing inspection holes.
How is the degree of mild corrosion determined? Does a non-zero corrosion margin require the installation of inspection holes?
It is actually air; due to differences in its composition, corrosion can occur as well. Inspection holes should be installed depending on the specific circumstances.
The container with a capacity of 150L has a relatively small diameter, and its port can be used as an inspection hole.
The key here is to determine the diameter of the 150L container; if it exceeds 300, and the nozzles meet the requirements for handholes, then there is no need to add any additional inspection holes； If the access hole does not meet the requirements, an additional inspection hole must be created.
The 150L container has a small diameter; I think the connection ports can be used as inspection holes. If these ports do not meet the requirements for inspection holes or manholes, additional inspection holes need to be created.
Here’s a case for reference for the original poster: The equipment inside the instrument air drying units in my factory (such as drying towers and filters) does not have separate inspection ports. Personally, I tend to think that it is not necessary to include inspection holes. Moreover, the inspection methods can include various approaches such as external thickness measurement and endoscopy. This post was last edited by qldch2306 on 2009-3-4 08:28]
According to the HG standards, mild corrosion refers to a annual corrosion rate ranging from 0.05 to 0.13 mm, with a corrosion allowance of 1 mm or more. The normal diameter of a 150L air tank is around 450mm; if it can be confirmed that there is only slight corrosion, then it is not necessary to create inspection holes.
Please introduce the medium. For a cylinder with a capacity of 150 LD and an inner diameter of ≤300 mm, according to Article 46 of the dimensional specifications, it is possible to omit the installation of inspection holes if it meets one of the specified conditions
150L, diameter 450mm; the medium is compressed air from the factory’s air compression station, with a working pressure of 0.8MPa. The pipe connection diameter is 50mm, and the material used is 16MnR. Some people believe that since there is only mild corrosion, it may not be necessary to install inspection holes. Some people say that air is corrosive, and unless stainless steel materials are used, inspection holes must be created