Building Green

Green Glossary


The American Society of Heating, Refrigerating and Air-Conditioning Engineers is an international organization committed to advancing heating, ventilation, air conditioning and refrigeration to serve humanity and promote a sustainable world through research, standards writing, publishing and continuing education. ASHRAE 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, has become the basis for building codes and the standard for building design and construction related to energy efficiency and methods of determining compliance.

Black Body

A theoretical object that absorbs all radiation incumbent upon it, turning it into heat. Conversely, it must also emit radiation at the maximum possible intensity for a given temperature.

Cool Roof

A cool roof reflects and emits the sun’s heat back to the sky instead of transferring it to the building below. “Coolness” is measured by two properties, solar reflectance and thermal emittance. Both properties are measured from 0 to 1 and the higher the value, the “cooler” the roof.

Energy Modeling

A computer model used to analyze a building’s energy systems in order to project its possible consumption rate.

Heat Island Effect

The increase in ambient temperature that occurs over large paved areas compared to natural landscape.

Insulated Metal Panel

A roof or wall panel composed of inner and out metal skins that encapsulate an insulating core, usually made of rigid plastic foam.

Light Transmitting Panels

A translucent roof or wall panel, typically made of reinforced acrylic plastic that can be used as a method of allowing natural light into an enclosed space.


A source or drain of heat that affects the design of the Heating, Ventilation and Air Conditioning (HVAC) systems in a building. Loads may be from internal sources, such as persons or equipment, or from the external environment.

Low-Emitting Materials

Materials, usually used as adhesives, sealants, or coatings, that can be shown to emit a relatively low amount of Volatile Organic Compounds (VOC) through some definitive criterion or test.

Mill Test Report

Documentation supplied by a producer of a steel product that certifies the chemical composition and mechanical test results required by a material specification, such as the American Society of Testing and Materials (ASTM).

Solar Reflectance

Sometimes referred to as reflectivity or albedo, solar reflectance is a value between 0 and 1 that represents the fraction of incumbent energy reflected by a body or surface. Reflectivity is determined by ASTM C1549, E903 or E1918.

Solar Reflective Index

SRI is an alternative method for considering the radiative properties of roofing materials. SRI is defined by ASTM Standard E1980-01 and is a calculation that uses solar reflectance and thermal emittance. EPA summarizes SRI as “the relative steady-state surface temperature with respect to the standard white (SRI=100) and standard black (SRI=0) under the standard solar and ambient conditions.

Thermal emittance

Sometimes referred to as emissivity, thermal emittance is a value between 0 and 1 that represents the energy radiated from an object relative to a black body at the same temperature. Emittance is determined by ASTM C1371 or E408.

Valley gutters

Specially designed gutters, usually located in a roof valley or behind a parapet or mansard that allow rainwater to drain from a roof surface.