Department for Transport issues electric vehicle guidance for recovery operators

Government document outlines hazards involved in roadside recovery of electric and hybrid electric vehicles

Department for Transport issues electric vehicle guidance for recovery operators

Guidance for recovery operators that work with electric and hybrid electric vehicles has this week been issued by the Department for Transport.

Battery electric vehicles (BEVs), plug-in hybrids (PHEVs), hybrid electric vehicles (HEVs) accounted for 27.5 per cent of the new car market in 2021.

The newly published government guidance outlines best practice advice for operators, including how to safely move a electrified vehicles and what to do if submerged in water.

It also advises on cases involving fire or thermal runaway hazard and chemical hazards.

The document introduction reads: “There has been a rapid increase in vehicles with an electric powertrain on the public roads, which use high voltage systems incorporating a high energy battery and this trend will continue.

“The high voltage (HV) systems used in these vehicles pose different hazards to those you may find on an internal combustion engine vehicle and these need to be considered while working with these vehicles.

“The information in this document provides a reference for professionals involved in the roadside recovery of electric vehicles, to better understand the hazards associated with these vehicles and the expectations on themselves and others.”

Moving an EV

It is not recommended to tow EVs on their wheels because this can cause electrical power to be generated, which can cause damage to the HV systems.

Manufacturers recommend EVs should only be transported on a flat-bed truck or on a trailer, with all four wheels off the ground – some may allow towing if the driven wheels are off the ground.

EVs submerged in water

If an EV is submerged in water, the DfT advises operators to refer to the vehicle’s emergency response guide and follow industry guidelines on vehicle recovery from water.

If the submerged vehicle is still attached to a charger, the charger should be made safe and the charge lead
removed before any recovery operation.

In general, the HV systems are isolated from the chassis and are designed for protection against water ingress and being in the water next to the vehicle does not pose any additional risk of electric shock.

Fire and thermal runaway

‘Thermal runaway’ occurs when the battery becomes unstable and an uncontrolled chemical reaction causes it to overheat, often leading to a battery fire.

The document warns that a fire to the main HV battery is a very severe incident and should not be tackled by the recovery operator.

A battery fire or thermal event will release toxic chemicals, posing a risk to health.

If a fire is starting from the low voltage supply (12/24 V battery) then a suitable extinguisher can be used to suppress the fire and stop it from spreading.

Current industry guidance is that a vehicle is deemed to be in a safe location if it is at least 15 metres away from anything else.

Damaged EV storage

Electric vehicles can reignite hours or even days after an incident, the DFT guidance explains.

It advises technicians to isolate the HV systems by disconnecting the low voltage system and removing the HV system manual service disconnect.

EVs with a suspected damaged HV system should be stored in an outside quarantine area where the fire risk will be monitored for up to 48 hours after an incident.

Where the HV battery temperature does not drop to ambient temperatures, it is advised to leave the vehicle in its safe.

Some vehicles have been know to ignite up to two weeks after an accident due to internal damage caused during an incident.

Vehicle movement during recovery or an internal fault such as coolant leakage, ingress of water or coolant drying out leaving behind conductive material may cause ignition.

5 Comments

  1. Sounds like more hassle than worth.

    So how you safely recover a crashed, burnt ev from a river that is still on charge?

    Reply
  2. Carefully

    Reply
  3. What about a crashed EV that is on fire with passengers inside that are trapped, would you try to get them out without know it is safe or choose to rescue the ones in the internal combustion engine vehicle. Hope this never happens though.

    Reply
  4. In the earlier days of EV’s Fire and Rescue personnel were told not to approach one involved in an accident until an “authorised person” told them it was safe to do so. This could have meant watching occupants burn to death while doing nothing to save them. I hope that training programmes have now over-ruled that advice.

    Reply
  5. Sounds like this raises more questions than it answers.For instance;
    How will the recocery operator know whether the fire started in the low voltage or High voltage system?
    It is a known fact that fires in HV sysytems cannot be extinguished at all.. By anyone…
    Lithium produces its own oxygen when it burns. Best of luck guys.

    Reply

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