Design Development

If the stormwater reduction goals are not met, the civil engineer needs to adjust the design to meet them.

The civil engineer verifies that post-development rate and quantity are equal to or less than pre-development.

The civil engineer calculates the pre- and post-development peak rate and total volume of stormwater runoff for the one-year and two-year, 24-hour design storms.

Case 1: Existing imperviousness is less than or equal to 50%

Consider maintenance costs in choosing stormwater strategies. Check with the product manufacturer, designer, or engineer for cost details.

Demand-control ventilation can help reduce peak load allow you to select smaller mechanical systems, minimizing upfront costs.

Integrating an ERV or HRV into a system that meets the Outdoor Air Delivery Monitoring credit can be particularly cost-effective with large centralized systems.

In laboratory and health care facilities, consider continuously measuring additional air quality factors such as TVOCs, carbon monoxide, and other small airborne particulates to reduce ventilation rates down to two air changes per hour (ACH), as conditions permit, in order to save energy.

CO₂ monitors installed in return-air ducts (in the ceiling or floor) will not meet the credit requirements, as monitors are required to be placed 3–6 feet above the floor in all densely occupied spaces.

Airflow measurement devices are installed as part of the air duct system and are designed to measure airflow and transmit a signal when airflow deviates from established set points. Two common types of these devices are those that measure intake volume directly by measuring air velocity (advanced thermal dispersion) and those that measure differential pressure across a fixed opening (pitot arrays and flow-rings). Both can provide the accuracy required for the credit. Advanced thermal diffusion is more accurate and requires less maintenance, but is more expensive.