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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Buildings that are likely to change use or be altered should consider a sgandard HVAC system design that could take into account changes in airflow rate requirements imposed by this standard. Great care should be given to the selection between these procedures. Various indoor air contaminants may give rise to odor that is unacceptable intensity or character that irritates the eyes, nose, and throat. Although outside airflow rates into many buildings have increased with the use of the technology, there is potential for an increase in building pressurization problems, which could lead to increased mold and fungal growth.
Since airflow rates are typically reduced in the Indoor Air Quality Procedure, its measurement and control is even more critical, especially on systems where the thermal load changes independent of the occupants and their activities.
Recirculation with air-cleaning systems is also an effective means for controlling contaminants when using the Indoor Air Quality Procedure. Moisture is a prerequisite for mold and fungal growth and the condition should be avoided.
At the writing of this document, addendum x was still under public review. Designers should be cautious when using CO2 measurement as the sole source of verification of outdoor airflow rates.
Standars effectiveness is discussed in 6. In addition, outside airflow rates will vary as a result of changes in mixed air plenum pressure. It is unlikely that all contaminants of concern will be evaluated or reduced to acceptable levels.
A revised procedure, addendum 62n, was under its third public review when this document was created. Once again, permanent airflow measuring stations would provide continuous outdoor airflow verification and provide necessary control inputs for an acceptable indoor environment.
The widespread use of energy recovery ventilators ERV in some geographic areas has decreased the amount of outside air used to pressurize a building. The section provides guidelines for air balancing, testing of drain pans, ventilation system start-up, testing of damper controls, and documentation requirements.
ASHRAE Standard 62-2001
Typically, the pressurization airflow, QP, is maintained at a fixed differential, regardless of the supply airflow rate required for temperature control. In addition, ahrae section should strongly encourage the use of airflow measuring devices in critical zones of VAV systems for the continuous calculation and asurae of the multi-space equation defined in section 6.
Its value as an indicator of actual ventilation rates is questionable. Using CO2 as an indicator of bioeffluents does not eliminate the need for consideration of other contaminants. The multi-space equation can result in wide variations in outside airflow requirements in some systems.
Interpretations for Standard
An area that only recently has received attention is the owner-occupant’s motivation to increase productivity and reduce the adverse impact a poor indoor environment can have on human health and well-being. The proposed addendum, only addresses azhrae pressure during periods of dehumidification. 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 stanxard space to space.
Standard 62 ashhrae been incorporated into many building codes. Especially in facilities with variable occupancy and activity levels. In reality, this latter scenario describes most facilities and suggests that outside airflow rates are directly set by the HVAC system based on design parameters, prior to occupancy.
Interpretations for Standard 62-2001
All systems constructed or renovated after the adoption date of the parent document are required to be operated and maintained in accordance to the provisions set 62-001 in this section of the standard.
Consideration should be given for a limited night setback mode with provision for humidity and pressurization control. This is a significant advantage over differential pressure airflow measuring technologies various pitot tube arrays and airflow measuring dampers and CO2 sensors, whose transmitters are often subject to drift.
HVAC system control strategies that ignore this relationship have inherent pressurization problems. In addition, the HVAC system must be able to maintain occupied spaces at positive pressure with respect to the construction areas. According to this section, “Under the ventilation rate procedure, for other than intermittent variable occupancy as defined in 6. In such cases, twice the amount of outside air as indicated in Table 2 would be required for acceptable indoor air quality.
Therefore, maintenance of minimum outdoor airflow defined in section 6 essentially requires the use of permanent devices capable of maintaining outdoor airflow rates for compliance.
The actual occupant dissatisfaction is exponentially greater in practice.
Designers claiming this procedure must be able to substantiate that rates are maintained during all load conditions. 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 absence of objective means to assess the acceptability of such contaminants, the judgment of acceptability must necessarily derive from subjective evaluations of impartial observers. Regardless of local code requirements, designing and operating a building to this standard will minimize IAQ liability and help assure an acceptable indoor environment.
The construction phase, section 7.