Interpretation Response #17-0037
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
August 15, 2017
Mr. Peter S. Ellenwood
Project Engineer
Paper Battery Company
165 Jordan Road
Troy, NY 12180
Reference No. 17-0037
Dear Mr. Ellenwood:
This letter is in response to your April 13, 2017, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to asymmetric capacitors. You explain that your company produces asymmetric capacitors that are classified as “UN3508, Capacitor, asymmetric, Class 9”; have energy storage capacity ratings of less than 20 watt hours (Wh) each; and have been successfully drop tested at heights of 1.2 meters or more. Specifically, you ask for the ground and air shipping requirements, such as documentation, labeling, marking, and packaging, for the capacitors described in your email.
- As prescribed in § 173.176, capacitors—including those containing an electrolyte that does not meet the definition of any hazard class or division as defined in Part 173 of the HMR—must conform to the following requirements:
- When an asymmetric capacitor's energy storage capacity is greater than 0.3 Wh, or when the energy storage capacity of each capacitor in a module is greater than 0.3 Wh, the capacitor or module must be protected against short circuit.
- Capacitors containing an electrolyte that meets the definition of one or more hazard class or division as defined in Part 173 of the HMR, must be designed to withstand a 95 kPa (0.95 bar, 14 psi) pressure differential.
- Capacitors must be designed and constructed to safely relieve pressure that may build up in use, through a vent or a weak point in the capacitor casing. Any liquid that is released upon venting must be contained by the packaging or by the equipment in which a capacitor is installed.
- Asymmetric capacitors manufactured after December 31, 2015, must be marked with the energy storage capacity in Wh.
- When an asymmetric capacitor's energy storage capacity is greater than 0.3 Wh, or when the energy storage capacity of each capacitor in a module is greater than 0.3 Wh, the capacitor or module must be protected against short circuit.
- Capacitors must be packed in strong outer packagings. For transport by air, capacitors must be securely cushioned within the outer packagings. Capacitors installed in equipment may be offered for transport unpackaged or on pallets, when the capacitors are afforded equivalent protection by the equipment in which they are contained.
- Capacitors containing an electrolyte not meeting the definition of any hazard class or division as defined in Part 173 of the HMR, including when configured in a module or when installed in equipment, are not subject to any other requirements of the HMR.
- Asymmetric capacitors containing an electrolyte that meets the definition of one or more hazard class or division as defined in Part 173 of the HMR, with an energy storage capacity of 20 Wh or less, including when configured in a module, are not subject to other provisions of the HMR when the capacitors are capable of withstanding a 1.2 meter (3.9 feet) drop test unpackaged onto a rigid, non-resilient, flat and horizontal surface without loss of contents.
- Asymmetric capacitors containing an electrolyte meeting the definition of one or more hazard class or division as defined in Part 173 of the HMR, that are not installed in equipment, and with an energy storage capacity of more than 20 Wh are subject to the requirements of the HMR.
- Capacitors installed in equipment and containing an electrolyte meeting the definition of one or more hazard class or division as defined in Part 173 of the HMR, are not subject to any other requirements of the HMR, provided the equipment is packaged in a strong outer packaging and in such a manner as to prevent accidental functioning of the capacitors during transport. Large, robust equipment containing capacitors may be offered for transport unpackaged or on pallets when the capacitors are afforded equivalent protection by the equipment in which they are contained.
It is the opinion of this Office that if the capacitors described in your email meet the requirements prescribed in § 173.176 (a) and (e), they are eligible for the exceptions from the documentation, labeling, and marking requirements of the HMR.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division
173.176, 173, 173.176 (a) and (e)
Regulation Sections
| Section | Subject |
|---|---|
| § 173.176 | Capacitors |