Air : 19-21 (Optimisation) Flashcards
What is DOAS?
Dedicated Outdoor Air System
What is the role of a DOAS?
Provides 100% outdoor air to a building’s zones for ventilation purposes
What are the benefits of a DOAS?
- Increased air filtration
- Increased energy efficiency
What is Feature 19?
Operable Windows
What project types does Feature 19 (Operable Windows) apply to?
All
- NEB
- NEI
- C&S
Natural ventilation effectiveness is affected by?
- Climatic conditions
- Outdoor air pollution levels
What are the 3 parts of Feature 19 (Operable Windows)?
- Full Control
- Outdoor Air Measurement
- Window Operation Management
What is the strategy for Part 1 (Full Control) of Feature 19 (Operable Windows)?
Operable windows in every regularly occupied space
What are the strategies for Part 2 (Outdoor Air Measurement) for Feature 19 (Operable Windows)?
- Outdoor-Air-Measurement Data Collection System
- Readings of select parameters
What is the range of the Outdoor-Air-Measurement Data Collection System of Part 2 (Outdoor Air Measurement) of Feature 19 (Operable Windows)?
Within 1.6km of the building
What are the parameters for readings for Part 2 (Outdoor Air Measurement) of Feature 19 (Operable Windows)?
- Ozone
- PM10
- Temperature
- Humidity
What is the strategy for Part 3 (Window Operation Management) of Feature 19 (Operable Windows)?
Methods to discourage occupants from opening windows when readings from Part 2 (Outdoor Air Measurement) exceeds limits
What are the methods for Part 3 (Window Operation Management) of Feature 19 (Operable Windows)?
- Software on computers or smartphones
- Indicator lights on operable windows
What are the limits for Part 3 (Window Operation Management) of Feature 19 (Operable Windows)?
- Ozone = <51 ppb
- PM10 = <50 UG/m3
- Temperature = +/- 8* of indoor temperature
- Humidity = 60% relative humidity
What is Feature 20?
Outdoor Air Systems
What project types (NEB; NEI; C&S) does Feature 20 (Outdoor Air Systems) apply to?
All
What are the strategies for Feature 20 (Outdoor Air Systems)?
Either
- DOAS complying with local codes or standards for DOAS
- Design review
What are the parameters for a DOAS Design Review for Feature 20 (Outdoor Air System)?
- Reviewed by a licensed mechanical engineer (M.E.)
- Addresses
- Thermal Comfort
- Ventilation Rate requirements of Feature 3 (Ventilation Effectiveness)
- System Serviceability and Reliability
What is Feature 21?
Displacement Ventilation
What project types (NEB; NEI; C&S) does Feature 21 (Displacement Ventilation) apply to?
- NEB
- NEI
What are Displacement Ventilation Systems?
Low-velocity air supplied at a low level to displace warmer air that is then extracted at ceiling level
What do Displacement Ventilation Systems help with?

Removal of pollutants concentrated towards the ceiling.
What are the 2 types of Displacement Ventilation Systems?
- Low Sidewall Air Distribution Systems
- Underfloor Air Distribution Systems (UBAD)
What are the parts for Feature 21 (Displacement Ventilation)?
- Displacement Ventilation Design and Application
- System Performance
What are the strategies for Part 1 (Displacement Ventilation Design and Application) of Feature 21 (Displacement Ventilation)?
- Displacement Ventilation Systems meeting minimum design standards
- Raised floor height allow for underfloor area to be cleaned annually
What are the minimum design standards for Low Sidewall AIr Distribution systems of Part 1 (Displacement Ventilation Design and Application) of Feature 21 (Displacement Ventilation)?
- System Performance Evaluation
- ASHRAE Guidelines RP-949
What is the design standard for UBAD systems of Part 1 (Displacement Ventilation Design and Application) of Feature 21 (Displacement Ventilation)?
ASHRAE UFAD guide
What is the strategy for Part 2 (System Performance) of Feature 21 (Displacement Ventilation)?
Meet 2 requirements
What are the 2 requirements for Part 2 (System Performance) of Feature 21 (Displacement Ventilation)?
- Must conduct a Computational Fluid Dynamics (CFD) analysis
- 75% of regularly occupied spaces meet the thermal comfort requirements of ASHRAE Standard 55-2013
What is the ASHRAE standard for meeting Thermal Comfort requirements of Part 2 (System Performance) of Feature 21 (Displacement Ventilation)?
ASHRAE Standard 55-2013
What are features 19, 20 and 21?
- Feature 19 = Operable Windows
- Feature 20 = Outdoor Air Systems
- Feature 21 = Displacement Ventilation