Report on fires in gas-powered buses in Horgvegen, Ranheim, Trondheim on 17 December 2016, and at Flatåstoppen Trondheim on 23 november 2016
Vei rapport 2017/04 eng
English translation now available. On the morning of December 17, 2016, it began to burn in a gas-powered local bus that ran on a route with three passengers aboard the Horgenvegen road in Trondheim. SHT initiated an investigation. It became known that a similar fire had occurred with another bus of the same type at Flatåstoppen in Trondheim on November 23, 2016. No people were injured. SHT has examined both fires and has found similarities. The Accident Investigation Board Norway`s investigation has shown that LED light technology can present a firerisk that can be challenging to handle and have major consequences. As a result of the survey, the AIBN believes that the regulations for the design of electrical installations in vehicles do not adequately protect fire safety.
The bus driver was informed about the fire by a passing vehicle, at a time when the bus had stopped at a bus stop. The bus driver evacuated the passengers, secured the bus and attempted to extinguish the fire, but this had no effect. The fire departement was called upon and eventually quenched the fire before it spread to the rest of the bus.
The gas-powered bus was the second bus of the same type that caught fire in a short period of time in the Trondheim area. The AIBN mainly investigated the fire on December 17, but found similarities with the fire on November 23, 2016.
Both fires have probably started in the LED lights that illuminated the rear license plate on the buses.
AIBN investigated and tested several new and used license plate lights, as well as conducted short-circuit tests of licence plate lights of the same type.
AIBN's investigation of the used LED-lights revealed cracks that were not compatible with normal influence of forces from attachment or normal use. The sign lights have most likely had cracks that created intrusion of moisture in the lights. Moisture with subsequent irradiation in circuit board components in LED light is therefore a likely source of ignition in both fires.
The investigation revealed weaknesses in the production of LED-lights, the electrical system and fuses in the busses, and the regulations for the design of electrical installations in busses.
Sikkerhetstilråding
Sikkerhetstilråding VEI nr. 2017/10T
To bussbranner i Trondheim i 2016 startet i skiltlysene av typen LED som belyste det bakre kjennemerket på bussene. Skiltlysene har etter all sannsynlighet hatt sprekker, som stammet fra en feil i produksjonen, og som muliggjorde fuktinntrenging i lysene. Ledningsnettet til skiltlysene var sikret med en 15 A sikring, som er for høyt for å hindre en brannfarlig kortslutning, og langt over hva lysprodusent anbefaler.
Statens havarikommisjon for transport tilrår at Solaris Norge gjennomgår og forbedrer dimensjonering av det elektriske anlegget på eksisterende og tilsvarende busser, slik at sikringskurser blir en effektiv barriere mot brann ved komponentfeil.
Sikkerhetstilråding VEI nr. 2017/11T
Undersøkelsen av to bussbranner i Trondheim i 2016 viste at bussenes originale glødepærer i skiltlysene var erstattet med nye LED-lys, som har andre egenskaper og annen konstruksjon. Ledningsnettet til skiltlysene var sikret med en 15 A sikring, langt over den strømstyrken et LED-lys trenger og hva lysprodusent anbefaler. Kjøretøyforskriften, og ECE 107 beskriver at det elektriske anlegget skal dimensjoneres etter kapasitet i sikringer og ledningsnett, men også at flere kurser kan være sikret av en enkelt sikring eller bryter. Regelverket spesifiserer imidlertid ikke hvilken kapasitet en krets med en enkelt sikring og flere forbrukere kan ha.
Statens havarikommisjon for transport tilrår Statens vegvesen å følge opp kravene i gjeldende regelverk om dimensjonering av sikringer og strømkurser slik at dette blir en effektiv barriere mot brann ved feil i alle typer (LED) elektriske komponenter.
Fakta
| Sted | Horgvegen, Ranheim, Trondheim and Flatåstoppen, Trondheim |
| Hendelsesdato | 17.12.2016 |
| Ulykkestype | Brann i kjøretøy |
| Veitype | Kommunal vei |
| Fylke | Sør-Trøndelag |
| Politidistrikt | Sør-Trøndelag |
| Kjøretøy/trafikant | Buss |
| Type transport | Persontransport |
| Veiregion | Region midt |
| Ulykkeskategori | Ulykke med buss |