What is the meaning of the closed line in the dimensioning of layout drawings?
Thread Content
In equipment layout drawings, when indicating the dimensions of equipment, the standards set by the Ministry of Chemical Industry specify that after listing all the individual dimensions, only the final one is shown, along with a total dimension. Why can’t all the individual dimensions be listed along with a separate total dimension?
The dimensions indicated in the diagram are meant to ensure compliance with those requirements; however, errors can occur during implementation. It is necessary to maintain precision for all dimensions (within the specified error range). Due to the accumulation of errors, it is inevitable that at least one dimension will not meet the precision requirements; therefore, it is advisable to leave one dimension unmarked (or indicate an approximate value enclosed in parentheses).
In other words, the space left is merely to facilitate construction. But now, when it’s drawn, the annotations show the exact numbers.
It doesn’t have much practical value; it’s fine to keep it closed