ASHRAE+62.1-2022+(1) - Page 014
Extracted Content
complying with the requirements of Section 5.7 is used to capture and remove any water that drops out of the airstream due to impingement on these obstructions.
5.9 Ozone-Generating Devices. The use of ozone-generating devices shall comply with the following sections. Exception to 5.9: Electronic devices used exclusively for the operation of HVAC equipment and controls.
Informative Note: Ozone generation is expected from ozone generators, corona discharge technology, some ultraviolet lights, electronic devices that create chemical reactions within the system, and some devices using a high voltage (>480 V). Motors and relays are examples of electronic devices that would be exempt.
5.9.1 Air-Cleaning Devices. Air-cleaning devices shall be listed and labeled in accordance with UL 2998. Informative Note: The use of devices not intended for air cleaning with the potential to generate ozone should be avoided.
5.9.2 Ultraviolet Devices. Ultraviolet-generating devices in supply air or spaces shall not transmit 185 nm wavelengths.
Informative Note: Ultraviolet devices used in treatment of closed water systems may produce 185 nm wavelengths, which may generate ozone.
5.10 Ventilation Air Distribution. Ventilating systems shall be designed in accordance with the requirements of the following subsections.
5.10.1 Designing for Air Balancing. Ventilation air distribution systems shall be provided that allow field verification of outdoor air intake flow ( Vot ) during operation.
5.10.1.1 Designing for Varying Loads and Operating Conditions. The ventilation air distribution system for variable-air-volume (VAV) and multispeed constant-air-volume applications shall be provided with means to adjust the system to achieve at least the minimum ventilation airflow as required by Section 6 under any load condition or dynamic reset condition.
5.10.2 Plenum Systems. When the ceiling or floor plenum is used both to recirculate return air and to distribute ventilation air to ceiling-mounted or floor-mounted terminal units, the system shall be engineered such that each space is provided with its required minimum ventilation airflow.
Informative Note: Systems with direct connection of ventilation air ducts to terminal units, for example, comply with this requirement.
5.10.3 Documentation. The design documents shall specify minimum requirements for air balance testing or reference applicable national standards for measuring and balancing airflow. The design documentation shall state assumptions that were made in the design with respect to ventilation rates and air distribution.
5.11 Airstream Surfaces. All airstream surfaces in equipment and ducts in the HVAC system shall be designed and constructed in accordance with the requirements of the following subsections.
5.11.1 Resistance to Mold Growth. Material surfaces shall be determined to be resistant to mold growth in accordance with a standardized test method, such as the mold growth and humidity test in UL 181, ASTM C1338, or ASTM D3273.
Exception to 5.11.1: Sheet-metal surfaces and metal fasteners.
Informative Note: Even with this resistance, any airstream surface that is continuously wetted is still subject to microbial growth.
5.11.2 Resistance to Erosion. Airstream surface materials shall be evaluated in accordance with the erosion test in UL 181 and shall not break away, crack, peel, flake off, or show evidence of delamination or continued erosion under test conditions.
Exception to 5.11.2: Sheet metal surfaces and metal fasteners.
5.12 Mechanically or Indirectly Evaporatively Cooled Buildings. Systems that cool by mechanical means or indirect evaporation shall be designed to limit the indoor humidity to a maximum dew point of 60°F (15°C) during both occupied and unoccupied hours whenever the outdoor air dew point is above 60°F (15°C). The dew-point limit shall not be exceeded when system performance is analyzed with outdoor air at the dehumidification design condition (that is, design dew point and mean coincident dry-bulb temperatures) and with the space interior loads (both sensible and latent) at cooling design values and space solar loads at zero. Exceptions to 5.12:
- Spaces equipped with materials, assemblies, coatings, and furnishings that resist microbial growth and that are not damaged by continuously high indoor air humidity.
- During overnight unoccupied periods not exceeding 12 hours, the 60°F (15°C) dew-point limit shall not apply, provided that indoor relative humidity does not exceed 65% at any time during those hours.
12 ANSI/ASHRAE Standard 62.1-2022