Billing Code - PHMSA - Department of Transportation

held by a capacitor, as calculated using the nominal voltage and capacitance.
Section 173.176 provides that capacitors not installed in equipment must be
transported in an uncharged state and capacitors installed in equipment must be transported
in either an uncharged state or protected against short circuit. Certain types of capacitors
such as asymmetrical capacitors are designed to maintain a terminal voltage. This special
provision also clarifies that the entry UN3499 does not apply to these capacitors. This
special provision is applied to the new HMT entry UN3499, “Capacitor, electric double
layer (with an energy storage capacity greater than 0.3 Wh).”
Veolia expressed concern that while manufacturers will have control over the
charge state of a capacitor when it is offered for transportation, when these same capacitors
are being offered for transportation for recycling or disposal, the recycling or disposal
facility may not be aware of or have control over their charge state. Veoila further asserted
that this special provision only applies to electric double layer capacitors with an energy
storage capacity of greater than 0.3 Wh, and there are other types of capacitors that have a
potential to store a significant amount of energy that may pose a risk during transportation.
The 0.3 Wh threshold for electric double layer capacitors is the threshold determined by
the UNSCOE below which a capacitor would not pose a significant risk in transportation.
PHMSA is aware that there are additional emerging capacitor technologies that are under
review by the UNSCOE for possible inclusion in the dangerous goods list.
In this final rule PHMSA is only addressing the adoption of the special provision
consistent with the amendment to the UN Model regulations. PHMSA has published an
advance notice of proposed rulemaking (ANPRM) under Docket HM-253 (77 FR 39662,
July 5, 2012) requesting public comment and input concerning the transportation of
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