- Every chamber, tank, vat, pipe, flue or other confined space, which persons may have to enter and which may contain dangerous fumes to such an extent as to involve risk of the persons being overcome thereby, shall, unless there is other effective means of egress, be provided with a manhole which may be rectangular, oval or circular in shape and which shall-(a)in the case of a rectangular or oval shape, be not less than 16 inches long and 12 inches wide.(b)in the case of a circular shape, be not less than 16 inches in diameter.
