Aug.4 (GMM) The ambient temperature at the Hungaroring is most likely to blame for the small fires during pitstops on Sunday.

Small fires blighted the pitstops of Honda's Rubens Barrichello and Williams' Kazuki Nakajima, while Sebastien Bourdais had fiery moments during two of his stops on Sunday and even had to stop again so Toro Rosso mechanics could clean fire extinguisher foam from his visor.

It is believed that so-called 'back-pressure' caused by the high temperatures in Hungary contributed to the problem in more than one case on Sunday.

But Honda sources are reporting that they believe Barrichello's small fire was caused simply because the nozzle was not applied completely squarely.

The heat may have affected the Intertechnique fuel rigs, but the drivers seemed unfazed at the end of the 70-lap race.

"I don't feel (the heat) limited or slowed me down at all," said race winner Heikki Kovalainen.

"It was ok," his Finnish countryman Kimi Raikkonen concurred. "It's harder for the cars, for everybody, but it was no problem."