Intent 

​

To provide additional outdoor air ventilation to improve indoor air quality (IAQ) and promote occupant comfort, well-being and productivity.

​

Requirements

​

Case 1. Mechanically ventilated spaces

​

Increase breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by ASHRAE Standard 62.1-2007 (with errata but without addenda) as determined by IEQ

​

Prerequisite 1: Minimum Indoor Air Quality Performance.

​

Case 2. Naturally ventilated spaces

​

Design natural ventilation systems for occupied spaces to meet the recommendations set forth in the Chartered

​

Institution of Building Services Engineers (CIBSE) Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings.  Determine that natural ventilation is an effective strategy for the project by following the flow diagram process shown in Figure 2.8 of the CIBSE Applications Manual 10.

 

AND

​

Option 1

​

Use diagrams and calculations to show that the design of the natural ventilation systems meets the recommendations set forth in the CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings, CIBSE AM 13 (Mixed Mode Ventilation), or natural ventilation/mixed mode ventilation related sections of the CIBSE Guide B2 (Ventilation and Air Conditioning).

​

OR

​

Option 2

​

Use a macroscopic, multi-zone, analytic model to predict that room-by-room airflows will effectively naturally ventilate, defined as providing the minimum ventilation rates required by ASHRAE 62.1-2007 Chapter 6 (with errata but without addenda 1 ), for at least 90% of occupied spaces.

​

 

Potential technologies & Strategies

 

For mechanically ventilated spaces: Use heat recovery, where appropriate, to minimize the additional energy consumption associated with higher ventilation rates.

​

For naturally ventilated spaces, follow the 8 design steps described in the Carbon Trust Good Practice Guide 237:

​

• Develop design requirements.

• Plan airflow paths.

• Identify building uses and features that might require special attention.

• Determine ventilation requirements.

• Estimate external driving pressures.

• Select types of ventilation devices.

• Size ventilation devices.

• Analyze the design.

​

Use public domain software such as NIST’s CONTAM, Multi-zone Modeling Software, along with Loop DA, Natural Ventilation Sizing Tool, to analytically predict room-by-room airflows.