Closely examine engineering design criteria. For instance if daylighting and otherwise high efficiency fixtures have greatly reduced the watts needed per SF, the heating and cooling tons should be adjusted accordingly. The site is part of the surrounding community and part of a larger environmental system. Optimization occurs when synergistic solutions are developed that meet multiple needs with a single solution. To accomplish this, team members work together across disciplines and through an interactive design process.
Specifications Be explicit.
These are all things that must be stated clearly. Define the process for evaluating proposed substitutions. One tactic is to limit the period of time when substitutions can be considered. Whenever possible, build in incentives that will increase the probability of success. What happens during construction will have a long-term impact on the site, water, waste, and indoor environmental quality.