Mitigation of emission of flames, molten metal, poisonous or ignitable substance

B

Bart de Visser

#1
We are developing a 1kW power supply (PSU) for medical equipment. The PSU needs to be 60601-1 2012 certified.

Subclause 13.1.2 states that emission of flames, molten metal, poisonous or ignitable substance in hazardous quantities shall not occur in single fault conditions.

To prevent this from happening, we considered the following options:

  1. We cannot use a fire enclosure. 60601-1 requires that the bottom of a fire enclosure cannot have holes. Our PSU can be used in any direction, so any side of the PSU can be the bottom. We need holes for several connectors (which don't cover the hole completely).
  2. Interpretation sheet 2 of the 60601-1 explaines that "Fire ENCLOSURES are intended to be used only where there is a significant likelihood of fire due to the presence of a source of ignition (as described in the subclause) and a significant source of fuel." We have several big 300uF 400V capacitors in our design. I think those are a great source of ignition and a great source of fuel.
  3. The PSU is placed in equipment. Using the equipment enclosure as fire enclosure is not allowed by the equipment manufacturer.
  4. We cannot test all single points of failure, because the number of SPFs is infinite.

Are we missing an option? Is our reasoning behind options 1 and 2 correct?
 
Elsmar Forum Sponsor

Peter Selvey

Staff member
Moderator
#2
The problem here is your client, not your design.

Most medical devices use the fire enclosure option as the only practical solution.

Solutions which do not make use of a fire enclosure are likely to be very simple, allowing the fault testing to be performed with confidence. Typically it would be applied only to parts of a device which contains only limited components and where a fire enclosure is impractical.

Fault testing as a means to prove no fire hazard is onerous because (a) the number of parts, (b) the number of failure modes, (c) number of operating conditions such as supply voltage and loading that can influence the result, and (d) the confidence that a test result is representative for regular production.
 
B

Bart de Visser

#3
Peter, thank you for helping out.

Are UL94 V0 connectors allowed to fill holes in the bottom of a fire enclosure?

Small round holes are allowed in the bottom, but is small spacing around a connector allowed?
 
Thread starter Similar threads Forum Replies Date
L Unacceptable risk for basic safety prior to or after mitigation? IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
G Risk Mitigation Through Outsourced Manufacturing EU Medical Device Regulations 7
Q Risk closeout , mitigation was not effective, next? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 12
F Is Testing ever a legitimate Risk Mitigation? ISO 14971 - Medical Device Risk Management 7
B FDA Software Failure Mitigation US Food and Drug Administration (FDA) 18
5 Counterfeit Parts Mitigation Plan/Procedure Details Requirement(s) Document Control Systems, Procedures, Forms and Templates 5
M Key Supplier Risk Mitigation - Supplier Changes or wants to change Sub-Tier Suppliers Supplier Quality Assurance and other Supplier Issues 5
M Trace Hazard Mitigation Requirements to Code Qualification and Validation (including 21 CFR Part 11) 4
T IEC 60601-1 Conformal Coating not an acceptable mitigation for creepage and clearance IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
Icy Mountain ESD Mitigation - Floor mats or conductive floor? Manufacturing and Related Processes 27
S IEC 60601-1-2 Radiated E-Field Emission Testing - Diagnostic ECG device IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
A EMC Emission Issues - Communication between PC and Monitor IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
C Uncertainty Estimation for Spark Optical Emission Device Measurement Uncertainty (MU) 1
R Optical Emission Spectrometer Calibration General Measurement Device and Calibration Topics 0
R EMS Programme Target is Reduction in CO2 Emission Miscellaneous Environmental Standards and EMS Related Discussions 5
T Optical Emission Spectrometer Calibration to a National or International Standard Various Other Specifications, Standards, and related Requirements 4
R Electrosurgery Emission Compatibility - Patient monitoring equipment IEC 60601 - Medical Electrical Equipment Safety Standards Series 5
W Who can do a noise emission test for us? CE Marking (Conformité Européene) / CB Scheme 3
Top Bottom