What is an acceptable grid size for confirmation sampling?
DEQ typically requires that confirmation sampling grids be 25 feet by 25 feet. However, alternate sampling strategies are considered on a facility-specific basis. For example, it may be appropriate to collect samples along radial lines extending from a known source of airborne contamination. It may also be appropriate to collect samples from larger grids on very large facilities; however, factors like heterogeneity of contamination must be considered in determining grid size. It is also important to balance analytical costs with the cost of remediating larger grids that do not meet cleanup levels.
