How to Read a Chemical Resistance Chart
Finding the right pump for a chemical application can be more than a bit tricky, and that's going to be particularly true if you don't know all of the properties of whichever chemical you'll be working with. Nevertheless, dealing with chemicals properly is tremendously important because of how much damage they can cause to the environment when they're handled improperly. You simply can't afford to use the wrong chemical pump, so you'll need to take care to match the right pump to chemical application. How? You'll need to use a chemical resistance guide. The chemical resistance chart is designed to help you select a pump constructed of materials most resistant to the chemicals you'll be pumping. Remember, using the wrong pump can result in damage to the pump, your facility and the environment.
Before you attempt to read a chemical resistance guide, you'll need to know various properties of the liquid you plan to pump. You'll need to know the specific name of the liquid, the concentration you'll be pumping, and the temperature you'll be pumping it at; but the liquid's PH probably won't be helpful.
Reading a Chemical Resistance Guide
First, pull up the chemical resistance chart you need, in this case, the March Pump Chemical Resistance Chart. As you can see in the paragraph up top, the chemicals thereon have been evaluated at 68F. The first column is the chemical name and the second column is the chemical formula. The third is the maximum concentration the materials have been evaluated at and the fourth is the specific gravity at 100% concentration. The remaining columns are grades for different materials with the chemicals in question. "A" means excellent, "B" questionable, and "C" not recommended.
Next, find the chemical you'll be pumping on the chart. The chemicals are listed in alphabetical order so that shouldn't be too difficult. You'll want to be sure the chemical concentrations in your application will be less than the maximum list concentration. You'll want to take not of any material that does not receive an "A" grade.
Then, find a pump on our website that meets your flow and head requirements. On every pump page you'll see a box titled "Wet End" that includes a list of that pump's components and construction materials. Make sure all of the materials in the wet end are compatible with the chemicals you'll be pumping. If they aren't, check the text below the pump to see if there are alternative materials available. If there seems to be nothing, you may have to go to a different pump, or you can call the factory and we may have something not listed. Rather than consulting the chemical resistance chart first, you can also start by selecting a pump based on your flow and head needs, find out which materials make up its "Wet End" and then checking to see if they are resistant.
If the temperature is greater than ambient or near freezing, or if the concentration is above the maximum concentration listed, please contact the factory for assistance. March has a ton of information on hundreds of chemicals concerning how they react to materials at different concentrations and temperatures. It's impractical to put that all on a sheet or website, so just give us call.