§571.301. Standard No. 301; Fuel system integrity. — Inbound Citations

(6) Motor carriers engaged in the private transportation of passengers may continue to operate a commercial motor vehicle which was not subject to this section or 49 CFR 571.301 at the time of its manufacture, provided the fuel tank of such vehicle is maintained to the original manufacturer's standards.

(2) Buses with 7 or fewer designated seating positions rearward of the driver's seating position that are forward-facing or can convert to forward-facing without the use of tools.

S4. Definitions.

Occupant compartment means a space within the vehicle interior intended for driver and passenger use, excluding any space occupied by fixed appliances such as bars, kitchenettes, or toilets.

Over-the-road bus means a bus characterized by an elevated passenger deck located over a baggage compartment.

Prison bus means a bus manufactured for the purpose of transporting persons subject to involuntary restraint or confinement and has design features consistent with that purpose.

School bus is defined in § 571.3.

School bus derivative bus means a bus that meets Federal motor vehicle safety standards for school buses regarding emergency exits (§ 571.217), rollover protection (§ 571.220), bus body joint strength (§ 571.221), and fuel system integrity (§ 571.301).

Stop-request system means a vehicle-integrated system for passenger to use to signal to a vehicle operator that they are requesting a stop.

Survival space means all points within a three-dimensional space in the occupant compartment as defined within the following volume:

(c) A schoolbus with a GVWR greater than 10,000 pounds, whose fuel system is filled as specified in S7.1.1 and S7.1.2, is loaded to its unloaded vehicle weight, plus 54.4 kg. (120 lb.) of unsecured weight at each designated seating position.

S7.1.7 The ambient temperature is not to vary more than 5.6 °C (10 °F) during the course of the test.

S7.1.8 The pressure drop measurement specified in S5.2 is to be made using a location on the high pressure side of the fuel system in accordance with the vehicle manufacturer's recommendation.

S7.2 Lateral moving barrier crash test conditions. The lateral moving barrier crash test conditions are those specified in S8.2 of Standard No. 208, 49 CFR 571.208.

S7.3 Rear moving barrier test conditions. The rear moving barrier test conditions are those specified in S8.2 of Standard No. 208, 49 CFR 571.208, except for the positioning of the barrier and the vehicle. The barrier and test vehicle are positioned so that at impact—

(b) Electric energy storage/conversion devices located outside the occupant compartment shall not enter the occupant compartment.

S5.3 Electrical safety. After each test specified in S6 of this standard, each high voltage source in a vehicle must meet one of the following requirements: electrical isolation requirements of subparagraph (a), the voltage level requirements of subparagraph (b), or the physical barrier protection requirements of subparagraph (c).

(b) Mandatory applicability begins September 1, 2027, for vehicles with a gross vehicle weight rating of 4,536 kilograms (kg) or less and September 1, 2028, for vehicles with a gross vehicle weight rating over 4,536 kg. Small-volume manufacturers, final-stage manufacturers, and alterers are provided an additional year to comply with the requirements beyond the dates identified in this paragraph (b).

S4. Definitions.

Active driving possible mode means the vehicle mode when application of pressure to the accelerator pedal (or activation of an equivalent control) or release of the brake system causes the electric power train to move the vehicle.

Automatic disconnect means a device that when triggered, conductively separates a high voltage source from the electric power train or the rest of the electric power train.

Breakout harness means connector wires that are connected for testing purposes to the REESS on the traction side of the automatic disconnect.

Capacitor means a device used to store electrical energy, consisting of one or more pairs of conductors separated by an insulator: x-capacitors are connected between electrical mains or neutral and y-capacitors are connected between a main to ground.

Charge connector is a conductive device that, by insertion into a vehicle charge inlet, establishes an electrical connection of the vehicle to an external electric power supply for the purpose of transferring energy.

Chassis dynamometer means a mechanical device that uses one or more fixed roller assemblies to simulate different road conditions within a controlled environment and is used for a wide variety of vehicle testing.

Connector means a device providing mechanical connection and disconnection of high voltage electrical conductors to a suitable mating component, including its housing.

n C Rate means the constant current of the REESS, which takes 1/n hours to charge or discharge the REESS between 0 and 100 percent state of charge.

Direct contact is the contact of any person or persons with high voltage live parts.

Electric energy storage device means a high voltage source that stores energy for vehicle propulsion. This includes, but is not limited to, a high voltage battery or battery pack, rechargeable energy storage device, and capacitor module.

Electric energy storage/conversion device means a high voltage source that stores or converts energy for vehicle propulsion. This includes, but is not limited to, a high voltage battery or battery pack, fuel cell stack, rechargeable energy storage device, and capacitor module.

Electric energy storage/conversion system means an assembly of electrical components that stores or converts electrical energy for vehicle propulsion. This includes, but is not limited to, high voltage batteries or battery packs, fuel cell stacks, rechargeable energy storage systems, capacitor modules, inverters, interconnects, and venting systems.

Electric power train means an assembly of electrically connected components which includes, but is not limited to, electric energy storage/conversion systems and propulsion systems.

Electrical chassis means conductive parts of the vehicle whose electrical potential is taken as reference and which are:

(1) Conductively linked together, and

(2) Electrical isolation of a high voltage source in the vehicle means the electrical resistance between the high voltage source and any of the vehicle's electrical chassis divided by the working voltage of the high voltage source.

Electrical protection barrier is the part providing protection against direct contact with high voltage live parts from any direction of access.

Electrolyte leakage means the escape of liquid electrolyte from the REESS.

Exposed conductive part is a conductive part that can be touched under the provisions of the IPXXB protection degree and that is not normally energized, but that can become electrically energized under isolation fault conditions. This includes parts under a cover if the cover can be removed without using tools.

External charging mode means the vehicle mode when the REESS is charging with external electric power supply connected through the charge connector to the vehicle charge inlet.

External electric power supply is a power supply external to the vehicle that provides electric power to charge the electric energy storage device in the vehicle through the charge connector.

Fuel cell system is a system containing the fuel cell stack(s), air processing system, fuel flow control system, exhaust system, thermal management system, and water management system.

High voltage live part means a live part of a high voltage source.

High voltage source means any electric component which is contained in the electric power train or conductively connected to the electric power train and has a working voltage greater than 30 VAC or 60 VDC.

Indirect contact is the contact of any person or persons with exposed conductive parts.

Live part is a conductive part of the vehicle that is electrically energized under normal vehicle operation.

Luggage compartment is the space in the vehicle for luggage accommodation, separated from the passenger compartment by the front or rear bulkhead and bounded by a roof, hood or trunk lid, floor, and side walls, as well as by electrical protection barriers provided for protecting the occupants from direct contact with high voltage live parts.

Normal vehicle operation includes operating modes and conditions that can reasonably be encountered during typical operation of the vehicle, such as driving, parking, and standing in traffic, as well as charging using chargers that are compatible with the specific charging ports installed on the vehicle. It does not include conditions where the vehicle is damaged, either by a crash or road debris, subjected to fire or water submersion, or in a state where service and/or maintenance is needed or being performed.

Parking mode is the vehicle mode in which the vehicle power is turned off, the vehicle propulsion system and ancillary equipment such as the radio are not operational, and the vehicle is stationary.

Passenger compartment is the space for occupant accommodation that is bounded by the roof, floor, side walls, doors, outside glazing, front bulkhead and rear bulkhead or rear gate, as well as electrical protection barriers provided for protecting the occupants from direct contact with high voltage live parts.

Propulsion system means an assembly of electric or electro-mechanical components or circuits that propel the vehicle using the energy that is supplied by a high voltage source. This includes, but is not limited to, electric motors, inverters/converters, and electronic controllers.

Protection degree IPXXB is protection from contact with high voltage live parts. It is tested by probing electrical protection barriers with the jointed test finger probe, IPXXB, in figure 7b to this standard.

Protection degree IPXXD is protection from contact with high voltage live parts. It is tested by probing electrical protection barriers with the test wire probe, IPXXD, in figure 7a to this standard.

Rechargeable Electrical Energy Storage System (REESS) means the rechargeable electric energy storage system that provides electric energy for electrical propulsion.

Rupture means an opening through the casing of the REESS that would permit the IPXXB test probe to penetrate and contact live parts.

Service disconnect is the device for deactivation of an electrical circuit when conducting checks and services of the vehicle electrical propulsion system.

State of charge (SOC) means the available electrical charge in a REESS expressed as a percentage of the normal operating capacity specified by the vehicle manufacturer.

Thermal event means the condition when the temperature within the REESS is significantly higher than the maximum operating temperature.

Thermal runaway means an uncontrolled increase of cell temperature caused by exothermic reactions inside the cell.

Thermal propagation means the sequential occurrence of thermal runaway within a REESS triggered by thermal runaway of a cell in the REESS.

VAC means volts of alternating current (AC) expressed using the root mean square value.

VDC means volts of direct current (DC).

Vehicle charge inlet is the device on the electric vehicle into which the charge connector is inserted for the purpose of transferring energy and exchanging information from an external electric power supply.

Venting means the release of excessive internal pressure from cell or battery in a manner intended by design to preclude rupture or explosion.

Working voltage means the highest root mean square voltage of the voltage source, which may occur across its terminals or between its terminals and any conductive parts in open circuit conditions or under normal operating conditions.

S5. General requirements.

S5.1 Vehicles of GVWR of 4,536 kilograms (kg) or less (light vehicles). Each vehicle with a GVWR of 4,536 kg or less shall meet the requirements set forth in S6 (normal vehicle operation safety), S8 (post-crash safety), S11 (vehicle controls managing REESS safe operations), S13 (warning in the case of thermal event in REESS), and S14 (water exposure safety) of this standard.

S5.2 Vehicles with a GVWR greater than 4,536 kg other than school buses (heavy vehicles other than school buses). Each heavy vehicle with a GVWR greater than 4,536 kg, other than school buses, shall meet the requirements set forth in S6 (normal vehicle operation safety), S11 (vehicle controls managing REESS safe operations), S13 (warning in the case of thermal event in REESS), and S14 (water exposure safety) of this standard.

S5.3 School buses with a GVWR greater than 4,536 kg. Each school bus with a GVWR greater than 4,536 kg shall meet the requirements set forth in S6 (normal vehicle operation safety), S8 (post-crash safety), S11 (vehicle controls managing REESS safe operations), S13 (warning in the case of thermal event in REESS), and S14 (water exposure safety) of this standard.

S6. Normal vehicle operation safety. Each vehicle to which this standard applies must meet the requirements in S6.1 to S6.6 of this standard, when tested according to the relevant provisions in S7 of this standard.

S6.1 Protection against direct contact.

S6.1.1 Marking. The symbol shown in figure 6 to this standard shall be present on or near electric energy storage devices. The symbol in figure 6 shall also be visible on electrical protection barriers which, when removed, expose live parts of high voltage sources. The symbol shall be yellow and the bordering and the arrow shall be black.

S6.1.1.1 The marking is not required for electrical protection barriers that cannot be physically accessed, opened, or removed without the use of tools. Markings are not required for electrical connectors or the vehicle charge inlet.

S6.1.2 High voltage cables. Cables for high voltage sources which are not located within electrical protection barriers shall be identified by having an outer covering with the color orange.

S6.1.3 Service disconnect. For a service disconnect which can be opened, disassembled, or removed without tools, protection degree IPXXB shall be provided when tested under procedures specified in S7.3.1 of this standard using the IPXXB test probe shown in figures 7a and 7b to this standard.

S6.1.4 Protection degree of high voltage live parts. (a) Protection degree IPXXD shall be provided for high voltage live parts inside the passenger or luggage compartment when tested according to the procedures specified in S7.3.1 of this standard using the IPXXD test probe shown in figure 7a to this standard.

(c) The fueling receptacle shall ensure positive locking of the fueling nozzle.

(13) ASTM D484-71, “Standard Specification for Hydrocarbon Drycleaning Solvents,” effective September 15, 1971, into § 571.301.