While design standards have mostly made buildings more safe over time, the COVID-19 pandemic exposed flaws in public health and safety policies. As a result, building standards that affect indoor air quality (IAQ) are being studied more now.
CURRENT STANDARDS ARE TOO LOW
In recent news, the Lancet Covid-19 Commission released a report on current IAQ standards. They found they don’t protect against the spread of infectious diseases in the air. The report considers ventilation, filtration, and disinfection rates in five types of small and medium-sized spaces. These include office, restaurant dining room, elementary classroom, hotel lobby, and supermarket. The report states, “there is no debate that the current targets are too low”.
The report provides helpful background. They discuss common building systems and how current standards are set. Most standards didn’t consider indoor air quality for disease vectors, except in hospital settings. Many standards do already address indoor air quality for particulates and poisonous gases. If the commission’s recommendations are put into place, one benefit will be a greater reduction in these, as well.
The commission analyzed existing standards and frameworks for indoor air quality as follows:
- · World Health Organization (WHO)
- · Centers for Disease Control and Prevention (CDC)
- · American Society of Heating, Refrigeration, Air Conditioning Engineers (ASHRAE)
- · Representatives of European Heating and Ventilating Associations (REHVA)
- · Federal Public Service (FPS) Health, Food Chain Safety and Environment of Belgium
The commission analyzed existing standards and frameworks for indoor air quality. The commission also performed a literature review from independent research teams known around the world. Then, they offer main points on the different approaches, relevant standards, and pros and cons.
The report presents different ways to compute the Non-infectious Air Delivery Rate (NADR). Similar to the Clean Air Delivery Rate (CADR), the NADR focuses on any mix of engineered controls that remove infectious particles from the air.
The analysis shows that the results are similar whether we use the volumetric flow rate per person (CFM/person), air changes per hour (ACHe (CFM/V)) or volumetric rate flow per floor area (CFM/ft2) approach. The Commission proposes NADR targets as new minimum standards as follows:
|Volumetric flow rate per volume||Volumetric flow rate per person||Volumetric flow rate per floor are|
|Good||4||21||0.75 + ASHRAE 62.1|
|Better||6||30||1.0 + ASHRAE 62.1|
|Best||>6||>30||> 1.0 + ASHRAE 62.1|
* cubic feet per minute
It’s important to note, these standards are achievable with existing technology.
ALIGNMENT ACROSS STUDIES
The commission looked at how similar results were when using different methods. They found:
- “The current ASHRAE ventilation rates are too low”
- “There is strong agreement between the ACHe approach and the volumetric flow rate per floor area approach.”
- “There is good agreement between the volumetric flow rate per person and the ACHe and volumetric flow rate per floor area approaches.”
- “Volumetric flow rate per person and CO2-based approaches were similar.”
- Approaches to reduce the spread of infection “were in between the occupancy based and ACHe approaches.”
KEY STUDIES OF BENEFITS
In this section, the report presents the other proven benefits of ventilation and filtration devices. Of course, researchers found reductions in particulates and harmful gases. Studies also showed improved health. Activities were less limited. Allergy symptoms were lower. Cognitive function and heart and lung health were improved.
ASHRAE’s standards are voluntary. The targets will be most helpful if they are turned into standards and adopted into state and local codes. To this end, ASHRAE’s board of directors has recently announced it supports the speedy development of a national IAQ pathogen mitigation standard. The standard intends to cover design and operation, alternative paths to achieving clean air, commissioning, and periodic re-commissioning.
As the COVID-19 pandemic and climate change have shown us, a goal to protect people’s health inside buildings while improving energy efficiency cannot be overstated. BuildingLens IAQ and energy management systems are already helping building managers stay ahead of the curve.
Building Lens can help meet and exceed the standard while still saving energy.