08-22: Construction Productivity Guidelines for Field Erected Cooling TowersConstruction contacts on field erected cooling towers have two major types of cost: fixed and variable. Fixed costs are costs a contractor procures on a fixed price. Variable costs are items such as labor, supervision, equipment and job overhead. On many field erected cooling tower projects, the largest single area of cost overrun is in supervision and labor costs. This is not surprising, because supervision and labor are frequently the largest