The Concrete Network

Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids, including many types of sealers. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. In addition to sealers, VOCs are emitted by a wide array of products including paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials, and even furnishings.

Depending on the environmental regulations in effect where you work, VOC limits range from 100 to 400 grams per liter. The typical VOC content in solvent- and water-based concrete cures, cure and seals, and sealers ranges from 100 to 780 grams per liter. It is your responsibility to use a product that meets VOC guidelines. Consult your regional EPA office or local government environmental office to obtain the VOC limits in your area.

Not all solvents are considered to be a VOC. The government uses a complex formula to determine which solvents are harmful. As local, state and federal governments clamp down on VOC emissions, manufacturers are being forced to reformulate their products to bring them within VOC tolerance (or eliminate them from the market altogether). This means that the sealers and coatings you are accustomed to applying may have changed in formulation. The most common change has been a reduction in xylene (a VOC producer) and an increase in acetone (a non-VOC producer). While this switch has virtually no effect on the performance of sealers and coatings, it can have other consequences, such as making the product difficult to roll out, faster drying times, an increase in spider webbing, surface blistering, and an increase in cost. We will discuss these issues more in later installments.

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Author Chris Sullivan, technical expert and vice president of sales and marketing for ChemSystems Inc.