ANSI/ASHRAE Standard (Including ANSI/ASHRAE Addenda listed in Appendix H). Ventilation for Acceptable. Indoor Air Quality. Ventilation standards and mechanical codes have evolved to address ASHRAE Standard (2). Ventilation for .. ASHRAE Standard The Ventilation Rate Procedure found in ASHRAE Standard Addendum N was applied to Monmouth University’s Multipurpose Athletic.
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However, there are numerous risks associated with both the quantitative and subjective evaluations provided within the procedure that every designer should be aware of.
In the Ventilation Rate Procedure, 4. HVAC system control strategies that ignore this relationship have inherent pressurization problems.
ASHRAE Standard 62-2001
Rates can be determined either directly using airflow measuring devices or indirectly by other means i. Net neutral control requires more precise instrumentation and the margin of error is much smaller. The critical space is that space with the greatest required fraction of outdoor air in standarv supply to this space.
Not requiring airflow measurement is analogous to ignoring the requirement for temperature measuring devices to maintain automatic temperature control. There is the potential for condensation to occur under a positive pressure environment during periods of humidification in cold climates since the dew point of the air within the building could potentially be greater than the temperature of the building envelope. At the writing of this document, addendum x was still under public review.
However, it neglects the significant influence of external pressure variations on all systems that result from changes in wind and stack pressures, which often exceeds 0. If properly executed, one out of five occupants may express dissatisfaction as a result of poor indoor air quality. Where more than one space is served by a common supply system, the ratio of outdoor air to supply air required to satisfy the ventilation and thermal control requirements may differ from space to space.
The proposed addendum, only addresses positive pressure during periods of dehumidification. They should also evaluate the IAQ risk of their design. Designers should exercise caution when implementing strategies that rely on ERV units for outside air and result in building pressures that are close to net neutral by design.
VAV systems with fixed outdoor air damper positions may not meet this requirement.
The system shall be designed to maintain the supply airflow and minimum ashrar airflow as required by section 6 under any load condition. The air cleaning system efficiency for the troublesome contaminants present, both gaseous and particulate, may be adequate to satisfy the Indoor Air Quality criteria of 6. The concept of providing “a direct solution” is desirable in principle.
ASHRAE Standard | Midwest Air Filter
Designers claiming this procedure must be able to substantiate that rates are maintained during all zshrae conditions. In reality, most systems require permanent airflow measurement devices to assure compliance with the standard. According to this procedure, 6.
The section provides guidelines for air balancing, testing of drain pans, ventilation system start-up, testing of damper controls, and documentation requirements.
Interpretations for Standard 62-2001
In addition, the section should strongly encourage the use of airflow measuring devices ashgae critical zones of VAV systems for the continuous calculation and reset of the multi-space equation defined in section 6. The statement, “in the absence of wind and stack effect” is of concern since external factors can significantly influence infiltration and exfiltration across the building envelope.
It is important to recognize that if the building asnrae altered or its use is changed, the ventilation system must be reevaluated. ASHRAE Standard 62 is a short, but often misinterpreted, document outlining ventilation requirements for acceptable indoor air quality. According to this section, “Under the ventilation rate procedure, for other than intermittent variable occupancy as defined in 6. Designers should provide an acceptable indoor environment to maintain occupant productivity and health.
Noteworthy is the standard’s definition of acceptable indoor air quality. Various indoor air contaminants may give rise to odor that is unacceptable intensity or character that irritates the eyes, nose, and throat.
Mechanical ventilation systems shall include either manual or automatic controls that enable the fan system to operate whenever the spaces served are occupied.
Interpretations for Standard
Designers should be cautious when using CO2 measurement as the sole source of verification of outdoor airflow rates. The designer, occupants, and facility owners should carefully consider the method employed prior to implementation. It incorporates both quantitative and subjective stajdard.