Part of FedOSHA?s Process Safety Management (PSM) requirements is up to date Process Flow diagrams and Material Safety Data Sheets. These are a facility owner?s responsibility. With these documents in place, electrical area classification (EAC) is fairly straight forward.
Section 500.4(A) requires that the EAC be properly documented and ??shall be available to those authorized to design, install, inspect, maintain, or operate electrical equipment at the location.? (It?s a PSM requirement too)
Both Don and Bob Gorno are right on. The end product (biodiesel) may be fairly benign, but the process creating it may be quite hazardous from an NEC Chapter 5 viewpoint.
If the test lab itself is built to NFPA 45, it may need little or no classified equipment.
EAC is not a trivial exercise. It needs to be created by someone who understands the project and the processes. The owner must provide this information as a matter of law and code.