ASHRAE-90.1-2022- - Page 078
Extracted Content
6.4.1.4 Verification of Equipment Efficiencies. Equipment efficiency information supplied by manu- facturers shall be verified by one of the following:
a. Equipment covered under EPACT shall comply with U.S. Department of Energy certification require ments. b. If a certification program exists for a covered product, and it includes provisions for verification and
challenge of equipment efficiency ratings, then the product shall be listed in the certification program. c. If a certification program exists for a covered product, and it includes provisions for verification and
challenge of equipment efficiency ratings, but the product is not listed in the existing certification program, the ratings shall be verified by an independent laboratory test report. d. If no certification program exists for a covered product, the equipment efficiency ratings shall be sup ported by data furnished by the manufacturer . e. Where components such as indoor or outdoor coils from different manufacturers are used, the system
designer shall specify component efficiencies whose combined efficiency meets the minimum equipment efficiency requirements in Section 6.4.1. 6.4.1.5 Labeling 6.4.1.5.1 Mechanical Equipment. Mechanical equipment that is not covered by the U.S. National Appliance Energy Conservation Act (NAECA) of 1987 shall carry a permanent label installed by the manu- facturer stating that the equipment complies with the requirements of Standard 90.1.
6.4.1.5.2 Packaged Terminal Air Conditioners. Nonstandard-size packaged terminal air condition- ers and heat pumps with existing sleeves having an external wall opening of less than 16 in. high or less than 42 in. wide and having a cross-sectional area less than 670 in. [2] shall be factory labeled as follows: “Manufactured for nonstandard-size applications only: Not to be installed in new construction projects.”
6.4.2 Calculations 6.4.2.1 Load Calculations. Heating and cooling system design loads for the purpose of sizing systems and equipment shall be determined in accordance with ASHRAE/ACCA Standard 183.
6.4.2.2 Pump Head. Pump differential pressure (head) for the purpose of sizing pumps shall be determined in accordance with generally accepted engineering standards and handbooks acceptable to the adopt- ing authority . The pressure drop through each device and pipe segment in the critical circuit at design conditions shall be calculated.
6.4.3 Controls and Diagnostics 6.4.3.1 Zone Thermostatic Controls 6.4.3.1.1 General. The supply of heating and cooling energy to each zone shall be individually controlled by thermostatic controls responding to temperature within the zone. For the purposes of this section, a dwelling unit shall be permitted to be considered a single zone.
Exceptions to 6.4.3.1.1: Independent perimeter systems that are designed to offset only building enve-
lope loads shall be permitted to serve one or more zones also served by an interior system, provided that
- the perimeter system includes at least one thermostatic control zone for each building exposure having walls facing only one orientation for 50 contiguous feet or more and
- the perimeter system heating and cooling supply is controlled by thermostatic controls located within the zones served by the system .
Exterior walls and semiexterior walls are considered to have different orientations if the exposures they face differ by more than 45 degrees. 6.4.3.1.2 Dead Band. Where used to control both heating and cooling, zone thermostatic controls shall be capable of and configured to provide a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum.
Exceptions to 6.4.3.1.2:
- Thermostats that require manual changeover between heating and cooling modes.
- Special occupancy or special applications where wide temperature ranges are not acceptable (such as retirement homes, process applications, museums, some areas of hospitals) and are approved by the authority having jurisdiction .
6.4.3.2 Set-Point Overlap Restriction. Where heating and cooling to a zone are controlled by separate zone thermostatic controls located within the zone, means (such as limit switches; mechanical stops; or, for DDC systems, software programming) shall be provided to prevent the heating set point from exceeding the cooling set point, minus any applicable proportional band.
76 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)