by Linnean Solutions — January 2017
Healthy buildings support happy people. As sustainable building practices advance, consideration for how a building can affect human health continues to grow. An essential piece of a healthy building is the quality of its indoor air. In fact, studies have shown that poor air quality not only affects health, but can also influence productivity and cognitive function.
Volatile organic compounds (VOCs) are a common air pollutant sourced from a variety of building products that have the potential to cause both short-term and long-term adverse health effects. For facility managers, understanding VOC emissions and how to control them can lead to a healthier environment for tenants.
Getting to the source
In older buildings, infiltration is a significant contributor to indoor air movement, often unintentionally supplementing designed ventilation rates, and playing a role in flushing VOCs from indoor spaces. But as new building envelopes get tighter in a push toward energy conservation, VOCs and other airborne contaminants tend to persist. While increasing ventilation rates is an effective solution to reduce the presence of airborne VOCs, it can also be costly.
A cheaper and easier solution is to tackle VOCs at the source.
Many common building materials contribute to VOC concentrations in the air, including carpets, paints, wall panels, adhesives, and furniture. Choosing products that have been tested for VOC emissions is a simple way for facility managers to improve indoor air quality.
VOC content vs. VOC emissions
In the 1970’s, the first building material-specific VOC regulations emerged in California, restricting the amount of VOCs present in wet-applied products like paints and adhesives. These regulations limited the “VOC content” of a material and were primarily intended to reduce the formation of photochemical smog in the outdoor environment. But in practice, the VOC content of a material provides little information about how it will contribute VOCs to indoor air.
In 2004, the California Department of Public Health (CDPH) released “California Specification 01350,” outlining a standard testing method to evaluate “VOC emissions” from indoor air sources.
How to test for VOC emissions
The CDPH 01350 method provides a uniform way to compare VOC emissions from various material types, but it’s important to understand exactly what the test results mean. Here’s an example:
A manufacturer who is seeking to certify a carpet product as having low VOC emissions will first need to send a sample to a laboratory. In the lab, the sample will be placed in an environmental chamber under controlled temperature, humidity, and ventilation conditions. Over a period of several days, the air within the chamber is tested and an emissions factor, or rate of VOC emissions, is calculated.
But the manufacturer cannot do much with this calculated emissions factor. The crucial information to know is whether the emissions factor will result in a harmful level of VOCs within a building.
To make this information more useful, the lab will then input the emissions factor value into a computer model to simulate how the VOCs emitted from the carpet will affect indoor air. Typical building scenarios are outlined in the CDPH 01350 standard for both an office and classroom environment with prescribed dimensions, ventilation rates, and amount of installed carpet.
The concentration of VOCs estimated by the model is then compared with chronic reference exposure levels (CRELs) established by the California Environmental Protection Agency. Because many products are present in a room at the same time, the CDPH 01350 standard indicates that any one material should not have a modeled VOC concentration that is greater than one half of the CREL. Depending on the type of VOC, concentrations above the CREL could pose significant health risks to exposed individuals.
Finding the right products
While the CDPH 01350 standard is not a law, it has become a widely accepted guide from which many material certification systems develop their criteria. Utilizing not only low VOC content but also low VOC emissions materials can help keep harmful concentrations in the air to a minimum and help keep building occupants healthy.
Many certification programs exist, but the following systems use part or all of the CDPH 01350 standard to certify building products with low VOC emissions:
- Indoor Advantage Gold
https://www.scsglobalservices.com/indoor-air-quality-certification - GreenGuard and GreenGuard Gold
http://greenguard.org/en/index.aspx - Green Label Plus
http://www.carpet-rug.org/green-label-plus.html - FloorScore
http://rfci.com/knowledge-center/floorscore/ - Cradle 2 Cradle Material Health Certification
http://www.c2ccertified.org/material-health-certificate
Many of these certifications are recognized by green building rating systems such as LEED, WELL Building Standard, Green Globes, and others.
Conclusion
VOC emissions testing is a developing area within the world of indoor air quality, and there is still no fool-proof way to ensure harmful VOC concentrations are kept out of buildings. A few things to keep in mind:
Not all VOCs are equal
There are many different types of VOCs and only some of them are tested for in current analytical methods. VOC testing was originally concerned with compounds that could contribute to smog formation, and thus the analytical methods may overlook non-smog-related, but hazardous VOCs.
Similarly, some VOC emissions certification programs base their criteria on the estimated concentration of total volatile organic compounds (TVOC), which is the sum of all detected VOCs. But while some VOCs are hazardous, others may only produce a harmless odor. As such, the TVOC value says little about potential health effects.
Typical scenarios might not be the best fit
Predicted indoor VOC concentrations are modeled using prescribed scenarios for an office or classroom environment. But the parameters used for these scenarios might not match the conditions of a specific building. A modeled concentration from the lab can be inaccurate due to actual variations in ventilation rates and the amount of a material present in a room.
For example, ventilation rates in residential settings tend to be lower than in a classroom setting. As a result, the same amount of paint applied in a classroom may create a lower indoor concentration of VOCs than in a residential room of the same size. Note, the CDPH 01350 standard does include a residential scenario as an appendix; however, this scenario is not as widely applied as the office and classroom versions.
VOCs are only a piece of the puzzle
VOCs are relatively well-understood and easy to measure, but they only represent a portion of potential indoor air quality problems. In addition to using low VOC emissions materials, it is also important to consider the control of mold, particulate matter, and other non-volatile chemicals in our indoor air.
Strategies for facility managers
Controlling the source of VOCs in indoor spaces by managing building materials is a cost-effective solution for facility managers to maintain healthy indoor air quality. In addition to increasing ventilation rates, these source-control strategies will help facility managers meet air quality goals.
- Explore online databases to identify and select certified interior materials and furniture that will emit fewer VOCs into indoor air. Be sure to read the certification criteria to ensure products meet the right standards. Several databases exist including UL’s Source for Product Sustainability Information (https://spot.ulprospector.com/en/na/BuiltEnvironment) and Pharos’ Building Product Library (https://www.pharosproject.net/).
- Consult indoor air quality specialists to evaluate how certain building materials may be affecting occupant health. Every building is different and tailoring concentration models to specific indoor conditions can more accurately predict exposure levels.
- Install air-monitoring equipment or periodically assess indoor air quality to ensure building occupants are not being exposed to harmful levels of airborne pollutants. Identifying sources of VOCs in a building will allow for targeted and effective material replacement plans.