EMC MDQS Page 7
GUIDE TO INSPECTIONS OF ELECTROMAGNETIC
COMPATIBILITY ASPECTS OF MEDICAL DEVICE
appropriate) of inspection or test equipment (e.g., for correct operation and electromagnetic emissions) are essential. Equipment used to detect electromagnetic emissions should operate within the limits specified for accuracy and precision and should be appropriate for the frequencies, field strengths, angle of incidence, and distance from the EMD source. The manufacturer should justify the inspection, calibration, and maintenance schedule for each piece of test equipment based on historical use, experience, vendor specifications, or a combination thereof.
21 CFR 820.72(b) Calibration
For some equipment, conformity or calibration to standards may be demonstrated by a classification marking on the piece of equipment or accompanying documents from a testing laboratory (e.g., Underwriters Laboratories, Inc.). This, however, does not obviate the need for routine calibration checks, maintenance, and recalibration.
21 CFR 820.70(c) Environmental Control
Since electronic components can be susceptible to damage from high levels of EMD,production and process controls should address EMI concerns. FDA investigators are generally aware of the need for ESD controls for printed circuit boards such as use of grounding devices (e.g., worker wrist straps) and use of appropriate plastic storage containers. In addition, the firm may need controls on such things as use of cellular phones and two-way radios in the manufacturing areas or very close (10-20 cm) to components and subassemblies, machinery qualifications for radiated emissions and/or ESD generation, the installation and distance from susceptible components of new machinery that may be a source of EMD, re-arrangement of existing machinery, and the susceptibility of the manufacturing and test equipment to power surges and outages.
21 CFR 820.140 and 820.150 Handling and Storage
Many electronic components (e.g. circuit boards) and subassemblies are very susceptible to EMD, particularly ESD. Verify the firm has documented and implemented procedures for minimizing damage similar to those needed for process controls, if appropriate to the device.
21 CFR 820.181 Device Master Record (DMR)
Investigators should verify that any instructions or procedures for production, installation, maintenance, and servicing related to ESD or other sources of EMD are included, or referred to, in the DMR. If the PMA or 510(k) includes EMC claims or test results, the DMR should include EMC design specifications and drawings, EMC test results, and possibly labeling and packaging specifications.
Electrical devices are subjected to many influences in the use environment, both expected and unexpected. Since radiated or conducted EMD is unseen and can be transient, EMI events are difficult to detect or duplicate. Sometimes the operation of a device recovers after an EMI event, sometimes the device must be reset by an operator, and sometimes the device is permanently damaged. Intermittent hardware malfunctions and software "bugs" can mimic EMI events and some intense EMD events can cause component failures.
21 CFR 820.198(a) Establish and Maintain Complaint Handling Procedures
The firm should process acquired information in a uniform and timely manner so that details are still fresh in the user's memory and all peripheral information can be synthesized to evaluate for:
- additional events which may have contributed to the EMI (e.g., construction