FCC Part 18 Testing Overview
FCC Part 18 is for Industrial, Scientific and Medical Equipment. It is one of the traditional parts of the Radio Frequency (RF) usages dating back several decades. After it was determined that RF energy can heat up materials, it was put to use in various processes that required contact-free heating: diathermy (thermal therapeutic applications), heat welding, material treating, melting and cooking.
Typical ISM applications are the production of physical, biological, or chemical effects such as heating, ionization of gases, mechanical vibrations, hair removal and acceleration of charged particles.
ISM also refers to ultrasonic equipment which can be used to weld and fuse materials. Typical applications include mating of plastic materials.
Magnetic Resonance Imaging (MRI) used widely in the health field is also an application of ISM use. The MRI equipment creates strong magnetic fields that align the spin of atoms in the human body. When the field is taken away, a resonance signal is produced which can be measured and resolved as an image.
ISM Frequencies have been defined by international treaty and set aside for such uses as described above.
Part 18 also applies to the use of microwave ovens. The frequency band of 2.4 GHz was selected years ago as the universal microwave cooking frequency. Because it was set aside as a non-communications band, this frequency was allocated as a band to be used for WiFi and other communications uses as unlicensed transmitter applications (See Part 15C of CFR 47).
Most of the equipment in Part 18 is industrial in nature, with the exception of consumer ISM equipment that includes residential microwave ovens and some cosmetic devices. Consumer ISM equipment typically requires Certification or approval under the Declaration of Conformity process (DOC). Consumer ultrasonic equipment generating less than 500 watts and operating below 90 kHz, and non-consumer ISM equipment shall be subject to verification, in accordance with the relevant sections of part 2 of the FCC Rules.
Scope of Services
Washington Labs provides radiated and conducted measurements to verify conformance with the Part 18 for Industrial Scientific Equipment. We can perform in-lab or on-site measurements. For in-lab measurements, we use an open area test site (OATS) or similar. In this application, the unit is placed on a non-conductive turntable (or, for floor-standing equipment, directly on the turntable) and the radiated measurements are performed over the proper frequency band.
Conducted emissions are also performed on the AC mains inputs. The conducted emissions must comply with the limits specified.
Standards and References
ANSI C63.4: American National Standard for Methods of Measurement of Radio Noise Emissions from Low Voltage Electrical and Electronic Equipment in the Range of 9kHz to 40 GHz. Procedures for verifying performance of compliance of lower power devices, primarily unintentional devices. Radiated and conducted methods, as well as layouts and reporting.
