Design Development

The mechanical engineer continues to run ventilation rate calculations during the mechanical design process to inform design development and confirm compliance with this prerequisite. The ventilation rate procedure is explained in section 6 of ASHRAE 62.1-2007. See the attached 62MZ calculator.

LEED for Schools projects can decide to exclude playing fields from the landscape calculation. However, the playing fields must then be excluded from all LEED calculations, including open space requirements. If such areas are included, they must be included in all other applicable Water Efficiency credit calculations (unless otherwise noted).

The landscape architect develops a baseline outdoor-water-use calculation based on mid-summer (July) and compares that to a calculation for the planned project design case water use (also for July). The difference is the percent reduction and identifies credit achievement. Factors included in the calculations are: plant species,

Perform LEED calculations to evaluate compliance. Only “softscape” areas are included in calculations. Projects that replace landscape irrigation with hardscape to reduce irrigation needs cannot count this area in their calculations.Use the calculator provided in the LEED Online credit form to evaluate compliance.

The mechanical engineer calculates the potential for graywater reuse and applicable treatment methods.

There are fewer codes and associated costs for collecting and using rainwater for irrigation than for interior water reuse.

The landscape architect calculates the potential for rainwater

The design cost of a drip irrigation system is generally comparable to a standard system. However, installation might be more expensive for drip irrigation, particularly as plant

Detailed calculations to demonstrate irrigation efficiency will be required from the landscape architect. The study “Performance and Water Conservation Potential of Multi-Stream, Multi-Trajectory Rotating Sprinklers for Landscape Irrigation” (see Resources) provides expected water conservation percentages derived from measured data. Efficiency ratings provided by manufacturers for irrigation components and controls can be used for calculations, but most manufacturers do not provide this data, so you’ll need additional calculations.