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14.3.1. Electrical and Electronic Flight Hardware Design Standards. Airborne electrical and electronic equipment shall be designed to meet the intent of NFPA 70, Article 501, Class I Locations, to the maximum extent possible.
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14.3.2. Flight Hardware Electromechanical Initiating Devices and Systems
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Electromechanical initiating devices and systems, including non-explosive initiators (NEIs), are used for such purposes as structure deployment or actuation release mechanisms.
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14.3.2.1. Electromechanical initiating devices and systems shall be evaluated to determine the severity of the hazard (Category A or B).
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14.3.2.2. Design, test, and data requirements shall be determined by the PSWG and Range Safety on a case-by-case basis.
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14.3.2.3. At a minimum, the system safety failure tolerances described in Chapter 3 of this volume and the initiating ordnance design requirements shall be addressed.
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14.3.3. Flight Hardware Batteries
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14.3.3.1. Flight battery cases shall be designed to an ultimate safety factor of 3 to l with respect to worst case pressure buildup for normal operations. For flight hardware batteries with LBB failure modes, 12.4.1.1 (factor of safety of 1.5) applies.
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14.3.3.1.1. This pressure buildup shall take into account hydraulic and temperature extremes.
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14.3.3.1.2. Batteries that have chemically limited pressure increases and whose battery/cell case can be designed to withstand worst case pressure buildup in abnormal conditions can reduce the safety factor to 2:1 (ultimate) and 1.5:1 (yield). Lower factors of safety determined by Range Safety approved analysis can be used on a case-by-case basis.
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Batteries that have nickel hydrogen chemistries are examples of batteries that have chemically limited pressure increases. Examples of abnormal conditions are direct short and extreme temperatures. Range Safety approved analyses include fracture mechanics that can be used on a case-by-case basis.
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14.3.3.2. Sealed batteries shall have pressure relief capability unless the battery case is designed to a safety factor of at least 3 to 1 based on worst case internal pressure.
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14.3.3.2.1. Pressure relief devices shall be set to operate at a maximum of 1.5 times the operating pressure and sized so that the resulting maximum stress of the case does not exceed the yield strength of the case material.
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14.3.3.2.2. Nickel-hydrogen batteries and/or cells that are proven by test to withstand worst case pressure buildup in abnormal conditions (such as direct short and thermal extremes that can be experienced when installed with no reliance on external controls such as heaters and air conditioning) are not required to have pressure relief capability.
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14.3.4. Test Requirements for Lithium Batteries. The following tests shall be performed before the use or storage of lithium batteries at a NASA facility or the payload processing facility and launch site area. These tests are likely to cause violent reactions, so all possible safety precautions shall be observed.
Note: Li-Ion battery safety see section 14.1.9.3.
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Batteries that have a UL listing and are intended for public use are exempt from these requirements.
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14.3.4.1. Lithium Battery Constant Current Discharge and Reversal Test
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14.3.4.1.1. The constant current discharge and reversal test shall determine if the pressure relief mechanism functions properly or case integrity is sustained under circumstances simulating a high rate of discharge.
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14.3.4.1.2. The test shall be performed according to the following criteria:
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14.3.4.1.2.1. The test shall consist of a constant current discharge using a DC power supply.
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14.3.4.1.2.2. The fusing of the battery shall be bypassed (shorted).
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14.3.4.1.2.3. The discharge shall be performed at a level equal to the battery fuse current rating and the voltage of the battery.
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14.3.4.1.2.4. After the battery voltage reaches 0 volts, the discharge shall be continued into voltage reversal at the same current for a time equivalent to l.5 times the stated ampere-hour capacity of the battery pack.
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14.3.4.1.2.5. Voltage, pressure, and temperature shall be continuously monitored and recorded.
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14.3.4.2. Lithium Battery Short Circuit Test
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14.3.4.2.1. The short circuit test shall determine if the pressure relief mechanism functions properly under conditions simulating a battery short circuit failure mode; or if a pressure relief mechanism is not provided, case integrity shall be determined under conditions simulating a battery short circuit failure mode.
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14.3.4.2.2. The test shall be performed according to the following criteria:
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14.3.4.2.2.1. After all internal electrical safety devices have been bypassed, the battery shall be shorted through a load of 0.0l ohms or less, leaving the load attached for not less than 24 hours.
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14.3.4.2.2.2. Voltage, current, pressure, and temperature shall be continuously monitored and recorded.
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14.3.4.3. Lithium Battery Drop Test. A drop test shall be performed according to the following criteria:
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Other tests may be required by the PSWG and Range Safety depending upon design, storage, operating environments, and other criteria. If required, additional tests shall be identified by the PSWG and Range Safety. Manufacturing lot acceptance tests may be required of safety devices in the battery design to ensure safety critical functions have not been altered.
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14.3.4.3.1. The battery in the activated state shall be dropped from a 3-foot height to a concrete pad on the edge of the battery, on the corner of the battery, and on the terminals of the battery.
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14.3.4.3.2. The battery shall not vent or start a hazardous event when dropped.
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14.3.4.3.3. A physical analysis shall be performed after the drop test to determine what handling procedures are required to safely dispose of the batteries if dropped at the payload processing facility and launch site area.
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14.3.5. Electrical and Electronic Equipment Data Requirements. EGSE data shall be submitted in accordance with the requirements of Attachment 1, A1.2.5.10 of this volume.
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