Chapel Hill, NC – Ben Kumpf (’18) and I are at the University of North Carolina at Chapel Hill to use their lab facilities for isotope analysis. We’re working with small amounts of sample and the instrument has a high degree of analytical precision and sensitivity, so all of our sample preparation occurs in the class-1000 clean lab. A clean lab is a room that is specifically designed to limit the amount of airborne contaminants. Special air filters and air distribution systems keep the environment clean so that we can minimize contamination while we separate and purify the isotopes.
Clean labs are classified based on the amounts of specifically sized particles allowed in a cubic meter (~35 cubic feet) of air. If we sample a cubic meter of air in the class-1000 lab and measure the amount of particles that are 5 microns in diameter, we would count no more than 293! For comparison, human hair has a diameter of about 50 to 100 microns, so we’re talking about really tiny bits of airborne dust. Class-1000 refers to Federal Standard 209E, where class-1 is the cleanest space and class-100,000 is the dirtiest (but still pretty darn clean). Federal Standard 209E has been replaced by International Organization for Standardization ISO 14644-1 standards. The new standards include one dirtier and two cleaner classifications and are numbered ISO-1 to ISO-9. Class-1000 is equivalent to ISO-6. UNC Chapel Hill also has a class-100 (ISO-5) clean lab where they process zircons for U-Pb dating.
Before we enter the clean lab, we gear up in the gowning room. The garments are designed to protect the wearer and minimize contamination from the wearer’s body. We wear standard lab safety attire, like glasses, gloves, and a lab coat. We also remove our shoes and exchange them for designated (comfy) slip-on shoes that only go in the clean lab.