This prerequisite establishes a baseline for providing a minimum amount of outdoor air to buildings in order to maintain good indoor air quality and keep occupants comfortable and healthy.
The referenced standard is ASHRAE 62.1-2010, which is a newer version than that referenced in LEED 2009. ASHRAE 62.1-2010 is often more stringent than local building codes, although it is not likely to entail any added costs.
The prerequisite has different compliance paths for mechanically ventilated and naturally ventilated spaces, and you may need to follow both paths for the same building on a space-by-space basis. In fact, teams should beware that ASHRAE 62.1-2010 effectively prohibits natural ventilation via operable openings as a stand-alone strategy. This is because the standard requires spaces to be mechanically ventilated whenever the operable windows are closed. Multifamily residential buildings may be most impacted by this type of scenario.
If the building relies on the fans for daily ventilation, it is considered a mechanically ventilated building.
Local codes may be used to meet the prerequisite if you can show equivalency with Sections 4 through 7 of ASHRAE Standard 62.1-2010. Alternatively, international projects can choose to comply with the minimum requirements of Annex B of CEN Standard EN 15251–2007, and meet the requirements of CEN Standard EN 13779–2007 excluding Sections 7.3, 7.6, A.16, and A.17.
To contribute to the comfort and well-being of building occupants by establishing minimum standards for indoor air quality (IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors.).
Meet the requirements for both ventilation and monitoring.
For mechanically ventilated spaces (and for mixed-mode systems when the mechanical ventilation is activated), determine the minimum outdoor air intake flow for mechanical ventilation systems using the ventilation rate procedure from ASHRAE 62.1–2010 or a local equivalent, whichever is more stringent.
Meet the minimum requirements of ASHRAE Standard 62.1–2010, Sections 4–7, Ventilation for Acceptable Indoor Air Quality (with errata), or a local equivalent, whichever is more stringent.
Projects outside the U.S. may instead meet the minimum outdoor air requirements of Annex B of Comité Européen de Normalisation (CEN) Standard EN 15251–2007, Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics; and meet the requirements of CEN Standard EN 13779–2007, Ventilation for nonresidential buildings, Performance requirements for ventilation and room conditioning systems, excluding Section 7.3, Thermal environment; 7.6, Acoustic environment; A.16; and A.17.
For naturally ventilated spaces (and for mixed-mode systems when the mechanical ventilation is inactivated), determine the minimum outdoor air opening and space configuration requirements using the natural ventilation procedure from ASHRAE Standard 62.1–2010 or a local equivalent, whichever is more stringent. Confirm that natural ventilation is an effective strategy for the project by following the flow diagram in the Chartered Institution of Building Services Engineers (CIBSE) Applications Manual AM10, March 2005, Natural Ventilation in Nondomestic Buildings, Figure 2.8, and meet the requirements of ASHRAE Standard 62.1–2010, Section 4, or a local equivalent, whichever is more stringent. [Europe ACP: Arbeitsstaettenrichtlinie ASR 5] [Latin America ACP: Engineered Natural Ventilation Systems]
The indoor air quality procedure defined in ASHRAE Standard 62.1–2010 may not be used to comply with this prerequisite.
For mechanically ventilated spaces (and for mixed-mode systems when the mechanical ventilation is activated), monitor outdoor air intake flow as follows:
For naturally ventilated spaces (and for mixed-mode systems when the mechanical ventilation is inactivated), comply with at least one of the following strategies.
In addition to the requirements above, if the project building contains residential units, each dwelling unit must meet all of the following requirements.
Cities in Canada that have been proven to have an average radon concentration of 4 pCi/L (150 Bq/m3) or less through testing in accordance with the Health Canada Guide for Radon Measurements in Dwellings (with a minimum of 50 tests) are considered equivalent to EPA Radon Zone 2, and therefore are exempted from the radon requirements of this prerequisite.
Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 as a local equivalent to ASHRAE Standard 62.1-2010, natural ventilation procedure.
Projects in Latin America may follow the Verification Protocol for Engineered Natural Ventilation Systems in Equitorial Climates and receive a design review and approval from the Colombian Professional Association of Air-conditioning, Ventilation and Refrigeration (ACAIRE).
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