## Health & Safety

Mathematically, what is a VOC?

The amount of VOCs in products are determined by calculating the amount of solvent present in a gallon or liter of ink, excluding water and EPA-exempt solvents, and expressed in either pounds per gallon, or grams per liter.

Knowing the weight per gallon (WPG) and the weight solids of a solvent-based ink, the VOCs can be calculated according to the following equation:

VOC = WPG x (100% minus % solids in product)

For example, a solvent based ink weighing 10.0 pounds per gallon and having a weight solids of 70% would have the following VOC amount:

VOC = 10.0 WPG x (100% - 70%)

VOC = 10.0 WPG x (30%)

VOC = 3.0 WPG (3.0 pounds of VOCs exist in each gallon of ink)

To convert pounds per gallon to grams per liter (g/L) use the following conversion factor:

Lb/Gal to g/L....multiply by 119.84

g/L to Lb/Gal....divide by 119.84

In the example above, to convert 3.0 Lb/Gal of VOCs to g/L, perform the following:

3.0 X 119.84 = 359.5 g/L (359.5 grams of VOCs exist in each liter of ink)