Civil Engineering - Tunnelling - Discussion

Discussion :: Tunnelling - Section 1 (Q.No.9)

9. 

Pick up the correct statement from the following during tunnel excavation,

[A]. Oxygen should not be less than 19.5%
[B]. Carbondioxide should not be more than 0.5%
[C]. Hydrogen sulphide should not be more than 0.001%
[D]. Carbon mono-oxide should not be more than 0.01%
[E]. All of the above.

Answer: Option E

Explanation:

No answer description available for this question.

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