Twenty-five separate incidents of explosion and fire involving electronic cigarettes (e-cigs or e-cigarettes) were reported in the United States media between 2009 and 2014. The task of coding the source of the explosion and fire can be difficult. This NFIRSGram will assist fire departments in coding these incidents in the National Fire Incident Reporting system (NFIRS) correctly.
The e-cigarette, also called a personal vaporizer or electronic nicotine delivery system, is a battery-powered device that simulates tobacco smoking by producing a heated vapor, which resembles smoke. There are millions of users and tens of millions of devices in use today, and the number is growing constantly. In general, the devices use a heating element known as an atomizer or cartomizer to vaporize a liquid solution. “Automatic” e-cigarettes activate the heater when a user inhales from the e-cigarette, while manual devices have an external switch that the user depresses to energize the heating element to create heated vapor.
Even with so many devices in use, fire-related incidents are very infrequent. These incidents are typically described in the media as small explosions. The event occurs suddenly and is accompanied by a loud noise, a flash of light, smoke, and flames; the battery and other parts are quite often launched across the room. The ejected battery often lands on or next to combustible materials, such as carpets, drapes or bedding, causing them to catch fire.
Descriptions and photographs of e-cigarette failures are consistent with known failures of lithium-ion polymer batteries, and reports of lithium-ion battery failures in mobile phones, laptops and other electronic devices are readily found. The causes of catastrophic failure of a lithium-ion battery can include puncture, overcharge, overheating, short circuit, internal cell failure and manufacturing deficiencies.
When the temperature of the battery rises, the electrolyte in the lithium-ion battery can ignite, resulting in overpressure, rupture of the cell, and ejection of the battery core from the case. (The electrolyte used in lithium-ion batteries is a flammable liquid.)
The majority of incidents reported by the media occurred while the battery was charging. A variety of charging sources were reported – laptop USB ports, auto USB adapters, desktop computer USB ports, and wall adapter USB ports.
The use of ordinary USB port charging connections may be one source of the problem. Few, if any, consumers understand that not all USB ports are “created equal.” The voltage and current provided by USB ports can vary. Without consulting the technical specifications for the computer or USB power adapter, it is difficult or impossible to determine the power supplied by any particular USB port and even more difficult to determine whether it is safe to use with a particular e-cigarette.
Plugging an e-cigarette into a “standard” USB port for recharge may subject the battery to higher current than is safe, leading to thermal runaway that results in an explosion and/or fire.
These facts illustrate the importance of using the proper charging devices with all rechargeable batteries.
|Heat Source||12 – Radiated or conducted heat from operating equipment.|
|Item First Ignited||This should be the item contacted by the device or battery, such as a curtain or chair cushion, as determined by the fire department.|
|Factors Contributing to Ignition||Select the correct failure code below.|
|Fails during charging||50 – Operational deficiency, other.|
|Fails any other time||40 – Design, manufacturing, installation deficiency, other.|
|Equipment Involved in Ignition||229 – Battery. This code is for all battery types, including lithium-ion batteries.|
|Equipment Power Source||The power source for e-cigarettes is lithium-ion batteries, so the best code to use for this is 12 – Batteries and low voltage (less than 50 volts).|
|Equipment Portability||1 – Portable.|