ASHRAE+62.1-2022+(1) - Page 071

Extracted Content

L5. SECTION 6 NATURAL VENTILATION PROCEDURE

Natural ventilation systems follow either the prescriptive or the engineered system compliance path.

For the prescriptive compliance path:

 Is a mechanical system compliant with either Section 6.2 or 6.3 included?  If no, does design comply with Exceptions 1 or 2 of Section 6.4.1?  Do maximum distances from openings comply with Sections 6.4.1.2, Section 6.4.1.3, or Section 6.4.1.4?  Do opening sizes comply with the requirements of Section 6.4.2?  Is net free area of openings specified?  Are sill-to-head heights specified?  Are aggregate widths specified?  Are controls readily accessible?

For the engineered compliance path:

 Do the design documents provide evaluation of the following?  Hourly environmental conditions, including, but not limited to, outdoor air dry-bulb temperature; dew-point temperature; outdoor concentration of contaminants of concern (including but not limited to PM2.5, PM10, and ozone), where data are available; wind speed and direction; and internal heat gains during expected hours of natural ventilation operation.  The effect of pressure losses along airflow paths of natural ventilation airflow on the resulting flow rates, including, but not limited to, inlet vents, air transfer grills, ventilation stacks, and outlet vents.  Qualification of natural ventilation airflow rates of identified airflow paths accounting for wind and thermally induced driving pressures.  Outdoor air is provided in sufficient quantities to ensure pollutants and odors of indoor origin do not result in unacceptable IAQ as established under Section 6.2.1.1 and/or 6.3.  Outdoor air introduced into the space through natural ventilation system openings does not result in unacceptable IAQ according to Sections 6.1.4.1 through 6.1.4.4.  Effective interior air barriers and insulation are provided that separate naturally ventilated spaces from mechanically cooled spaces, ensuring that high-dew-point outdoor air does not come into contact with mechanically cooled surfaces.  Are controls readily accessible?

L6. SECTION 6 EXHAUST

Exhaust ventilation systems follow either the prescriptive or the performance compliance path.

For the prescriptive compliance path:

 Does airflow comply with requirements of Tables 6-1 and 6-3?  If no for any space, does it qualify as an exception?  Have source strengths been evaluated as required in Section 6.5.1.1?

For the performance compliance path:

 Do the design documents provide evaluation of the following?  Compounds of interest for the design  Indoor sources and emissions rates for each compound  Outdoor sources and emissions rates brought in by ventilation air  Exposure periods and concentration limits  Evaluation of mixtures  Calculation of resultant concentrations from the design  If applicable, are appropriate specifications for dynamic reset monitoring and controls included?

ANSI/ASHRAE Standard 62.1-2022 69