The Italian Grand Prix has been declared a heat-hazard race as high temperatures continue in the country following the summer heatwave.
A heat hazard is an official designation for an event where it is forecasted that temperatures will be more than 31C at some point during the race on Sunday.
The ambient temperatures around Monza, north-east of Milan, are expected to be in the mid-30C region all weekend.
They peaked at 36C on Wednesday afternoon near Milan's Linate airport.
The ruling means drivers can use a system that flows cooled liquid, such as glycol, through a system of pipes in a fireproof top worn under their overalls.
The cooling kit is not mandatory, but any driver who chooses not to use it has to carry 5kg of ballast in their car to ensure they do not have a competitive advantage.
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Italy is the second race this year to be declared a heat hazard. The first was Austria early in the summer heatwave.
Some drivers prefer not to use the cooling kit because of discomfort, and because there have been issues with the coolant running out before a grand prix is finished.
In that case, the liquid ends up at car temperature, which is considerably higher than ambient.
Temperatures in the cockpit of an F1 car can be more than 40C, and drivers are wearing several layers of fireproof clothing in addition to a balaclava and helmet, so overheating is a serious concern.
