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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All of these variations can be compensated for by using an airflow measuring station at the intake to the air-handling unit with automatic controls.
Once more the Standard attempts to clear up the misunderstandings about CO2. Although this may sound impractical to some designers, the productivity and health benefits is far greater than the cost to satisfy the requirements for acceptable ashrze air quality. Not requiring airflow measurement is analogous to ignoring the requirement for temperature measuring devices to maintain automatic temperature control. Typically, the pressurization airflow, QP, is maintained at a fixed differential, regardless of the supply airflow asjrae required for temperature control.
Especially in facilities with variable occupancy and activity levels.
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. Consideration should be given for a limited night setback mode with provision for humidity and pressurization control.
A base ventilation rate will always be required, regardless of occupancy, to dilute such contaminants. Its value as an indicator of actual ventilation rates is questionable. Ventilation effectiveness is discussed in 6.
It is unlikely that all contaminants of concern will be evaluated or reduced to acceptable levels. As a result of the requirements set forth in the standard for compliance “under any load condition”, section 5 should require airflow measurement with automatic controls at the intake of all air-handling units that function to provide a building or space with outside air, regardless of the size sstandard the type 62-2010 system. 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.
Outside airflow rates can also be reduced if the critical zones have variable occupancy. Airflow sensors provided with VAV boxes should not be used for this calculation. In reality, most systems require permanent airflow measurement devices to assure compliance with the standard.
The system shall be designed to maintain the supply airflow and minimum outdoor airflow as required by asgrae 6 under any load condition.
Clearly airflow rates are part of this procedure. After determining the corrected fraction of outdoor air required, Y, the new outside airflow setpoint is determined by multiplying Y by the supply airflow rate, QSA.
Unfortunately there is no “cookbook” solution to ventilation for IAQ. In the Ventilation Rate Procedure, 4. It is important to recognize that if the building is altered or its use is changed, the ventilation system aehrae be reevaluated. It does not state the “indoor air quality shall be considered acceptable.
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.
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.
Using the steady-state model described in Appendix C of the Standard, 15 CFM per person would be the resulting quantity of outside air introduced into a space if a. It must also include individual sensor and transmitter uncertainties.
Addendum u was approved for incorporation into the parent document at the ASHRAE winter meeting in January and adds a new section, 5. Unfortunately, almost every facility has contaminants generated from within the space i.
Since there are numerous contaminants that either will not be detected or for which “definite limits have not been set”, this portion of the procedure has significant risk associated with it. Advanced VAV control strategies can satisfy the requirements of 6.
Recirculation criteria are defined in 6. 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.
When applied in accordance to manufacturer’s recommendations, airflow measuring devices such as those manufactured by EBTRON, only require the verification of operation by test and balance professionals.