Replaced fan efficiency grade (FEG) efficiency metric with fan energy index (FEI).
New equipment efficiency requirement tables and changes to existing tables.
Added pump definitions, requirements, and efficiency tables to the standard for the first time.
New requirements to allow the option of using ASHRAE Standard 90.4 instead of ASHRAE Standard 90.1 in computer rooms that have an IT equipment load larger than 10 kW.
Clarified side-lighting requirements and associated exceptions.
Updated daylight responsive requirements, added definition for “continuous dimming” based on NEMA LSD-64-2014.
Updated lighting control requirements for parking garages to account for the use of LEDs.
New simplified method for lighting for contractors and designers of renovated office buildings and retail buildings up to 25,000 ft2 (2300 m2).
Modified lighting power allowances for Space-by-Space Method and the Building Area Method.
Refined exceptions related to vestibules, added new option and associated criteria for using air curtains.
Revised air leakage section to clarify compliance.
Upgraded minimum criteria for SHGC and U-factor across all climate zones.
Combined categories of “nonmetal framed” and “metal framed” products for vertical fenestration.
New commissioning requirements in accordance with ASHRAE/IES Standard 202.
Significant changes to requirements include the following The 2019 edition includes various modifications and clarifications to improve internal consistency and to standardize the structure and language of the document. It is an indispensable reference for engineers and other professionals involved in design of buildings and building systems. It offers, in detail, the minimum energy efficiency requirements for design and construction of new buildings and their systems, new portions of buildings and their systems, and new systems and equipment in existing buildings, as well as criteria for determining compliance with these requirements. This standard provides the minimum requirements for energy-efficient design of most buildings, except low-rise residential buildings. It is also important to acknowledge how ASHRAE defines fenestration:įenestration: all areas (including the frames) in the building envelope that let in light, including windows, plastic panels, clerestories, roof monitors, skylights, doors that are more than one-half glass, and glass block walls.Standard 90.1 has been a benchmark for commercial building energy codes in the United States and a key basis for codes and standards around the world for more than 35 years. Projection factor (PF): the ratio of the horizontal depth of the external shading projection divided by the sum of the height of the fenestration and the distance fro the top of the fenestration to the bottom of the farthest point of the eternal shading projection, in consistent units. The ASHRAE definition of projection factor, as offered in ANSI/ASHRAE/IES Standard 90.1-2016, is as follows: The effectiveness has been defined as the projection factor. ASHRAE has defined a simplified method of accounting for a shading device’s impact on the performance of a glazing assembly by reducing (increasing the resistance of) the glazing assembly SHGC based on the effectiveness of the exterior shading device. When exterior shading devices are present on a building, the degree to which the devices protect the glazing assembly should be factored into considerations of energy performance. Meaning, only a small percentage of the Sun’s rays makes it through the window or skylight. That means most of the solar radiation arriving to the window or skylight is getting inside and turning into heat. It represents the ability of a glazing assembly to resist heat gain from direct solar radiation.Ī high SHGC indicates poor resistance. The solar heat gain coefficient (SHGC) is a ratio that defines the amount of solar energy that reaches a glazing assembly (including both the glass and frame) with the amount that gets through to the inside. Originally published on Februby BNP Media through the Building Enclosure Blog.