Quality Level A (QL-A)

The highest ASCE 38 quality level. The utility has been physically exposed — normally by a vacuum test hole — and its position, depth, material, and size measured and surveyed directly.

QL-A is the only quality level that reports a measured depth rather than an inferred one, and the only one that reports pipe material and outside diameter, which no surface method can determine. Because test holes cost money, normal practice is to designate a whole corridor at QL-B and then place QL-A holes only where the design actually conflicts: crossings, proposed foundations, and bore entry and exit points.