A06: Enhanced Ventilation

(3 points)

INTENT

Expel internally generated pollutants and improve air quality in the breathing zone through an increased supply of outdoor air or increased ventilation efficiency.

SUMMARY

This WELL feature requires implementation of advanced ventilation strategies that can secure higher air quality levels and thus benefit human health and productivity.

ISSUE

The majority of ventilation standards specify ventilation rates and other measures intended to provide indoor air quality that is merely “acceptable” to building users and that reduces the risk of adverse health effects. Even with proper ventilation designed to meet ventilation standards, the concentration of indoor pollutants can exceed concentrations found in outdoor air. Ventilation rates less than 10 L/s [21 CFM] per person in all building types are associated with negative perception of air quality and actual health outcomes.

SOLUTIONS

Unusually high building occupancy, a high risk of accidents that might degrade air quality or limited space capacity to install filtration make exceeding standard ventilation requirements a worthwhile strategy. Scientific research suggests that an airflow rate significantly exceeding that recommended by standards is needed to minimize sick building syndrome symptoms and to improve human performance and productivity. Because it is difficult to test for every potential pollutant, and because carbon dioxide (CO₂) is easy to detect, CO₂ levels serve as a proxy for other indoor pollutants.  A number of CO₂ studies suggest that the risk of sick building syndrome symptoms decreases significantly when CO₂ concentrations are less than 800 ppm. One method for decreasing the CO₂ concentration experienced by occupants while minimizing additional energy use is demand-controlled ventilation, in which the delivery rate for outside air is directly linked to the measured CO₂ levels within the space.

IMPACT

Ventilation systems designed primarily for human health are essential to good indoor air quality and play a fundamental role in creating healthy buildings.

REQUIREMENTS

Part 1

Increase Outdoor Air Supply (Max: 3 points)

Verified by MEP

For All Spaces

Choose between the following:

1. Mechanically ventilated spaces:

The following requirement is met:

• Projects exceed outdoor air supply rates described in ASHRAE 62.1-2010 by the percentages shown in the table below:

  Thresholds	Points
  30%	1
  60%	2

2. Naturally ventilated spaces:

The following requirements are met:

• Projects meet Part 1: Provide Operable Windows in Feature A07: Operable Windows.
• Projects demonstrate that natural ventilation is sufficient to keep CO₂ levels less than the thresholds specified in the table below (measured at 1.2-1.8 m [4-6 ft] above the floor) at maximum intended occupancies in all regularly occupied spaces:

  Thresholds	Points
  900 ppm	1
  750 ppm	2
  600 ppm	3

 

Part 2

Implement Demand-Controlled Ventilation (Max: 3 points)

Verified by MEP

For All Spaces

All regularly occupied spaces meet the following requirements:

• A demand-controlled ventilation system regulates the outdoor ventilation rate to keep CO₂ levels at maximum intended occupancy less than the thresholds specified in the table below:

Thresholds	Points
900 ppm	1
750 ppm	2
600 ppm	3

• Carbon dioxide is measured at the air exhaust diffusers or in occupied space at 1.1-1.7 m [3.6-5.6 ft] above the floor (away from doors, windows, air supply and zones where occupants may exhale directly into the sensor). At least one sensor is used for each major occupancy zone (or per air handling unit if a single zone is served by multiple air handling units). If occupancy density/pattern/usage is different in two adjacent areas, each area must be considered a separate zone.

Part 3

Implement Displacement Ventilation (1 point)

Verified by MEP

For All Spaces

Projects implement a displacement ventilation system for heating and/or cooling, with one of the following as a basis for design: 

• ASHRAE Guidelines RP-949.
• REHVA Guidebook No. 01 (Displacement Ventilation in non-industrial premises).
• ASHRAE's UFAD Guide: Design, Construction and Operations of Underfloor Air Distribution Systems. Air supply temperature is slightly cooler or warmer than the desired space temperature. Air distribution system is installed at a raised floor height whereby the underfloor area can be cleaned on an annual basis.

 

Part 4

Implement Advanced Air Distribution (Max: 3 points)

Verified by MEP

For All Spaces except Commercial Kitchen Spaces & Dwelling Units

At all workstations, the following requirements are met:

• Conditioned air is supplied via an individual diffuser that is positioned no further than 0.8 m [2.6 ft] from an occupant's head.
• Occupants are given control over the direction of the supplied airflow and supply air speed (within 0.0-1.2 m/s [0.0-3.9 ft/s] in the head region).
• Supplied air uses one of the strategies specified in the table below:

  Requirement	Points
  Background mechanical system is used for ventilation	2
  Dedicated outdoor air system is used for ventilation	3

  © International WELL Building Institute