Architects are sometimes asked to consider how future occupants will interact with and use products and materials in a building. Will the product make life easier and more convenient? Conversely, are there any concerns associated with the products and materials being used?
While architects are not expected to be experts on chemical materials, they are increasingly asked to make materials selection decisions. Thus it can be helpful for architects and others involved in the building process to have a basic understanding of issues related to potential effects from occupant exposure to chemicals in products.
Some building products may contain chemicals that architects or building occupants might have questions about. For example, a building product may contain a chemical ingredient identified by a news report, blog post or advocacy organization as harmful to human health. So does that mean the building product or material shouldn’t be used?
In fact, the mere presence of a chemical ingredient in a product does not mean that chemical is a risk, or will cause harm to people using the product. The level of risk is determined not only on the presence of the chemical itself, but also on how a person is exposed to the chemical, at what concentration and for how long, as well as the physical properties of the chemical itself.
For example, polyurethanes in spray polyurethane foam are formed by reacting a polyol (an alcohol with more than two reactive hydroxyl groups per molecule) with a type of chemical called diisocyanates. Most polyurethane products are fully “cured” before they are sold, meaning these products are fully reacted and therefore considered to be inert and non-toxic, according to the U.S. Environmental Protection Agency.
- Hazard refers to the inherent properties of a substance that make it capable of causing harm to a person or the environment.
- Exposure describes both the amount of, and the frequency with which, a substance comes into contact with a person, group of people or the environment.
- Risk is the possibility of a harm arising from a particular exposure to a substance, under specific conditions.
One way to look at levels of exposure is evaluating whether a substance is “in,” “on” or “near” a person. For example, spray foam insulation is located in the building envelope, NEAR the occupant but behind a sealed wall, so there is no direct contact with occupants post-installation. Carpeting can emit volatile organic compounds (VOCs) during the installation process, so the chemical can be ON the occupant who walks on the carpet or IN the occupant when inhaled. Builders should take care to follow appropriate guidelines during and post-installation to minimize exposure to these substances. When guidelines are followed correctly, VOC levels can be reduced to trace amounts post-installation.
The form that a chemical product takes when used also can determine potential risk or harm to human health. For instance, titanium dioxide, used in paints and coating to provide opacity and durability, is an inhalation hazard when in powder form. But in paint products the titanium dioxide is in liquid form, and thus poses little to no hazard.