Overview
- The FIA formally triggered the heat‑hazard rule on Thursday for the Italian Grand Prix after official forecasts showed heat‑index readings above the 31°C threshold and peak temperatures in the mid‑30s.
- Teams are required to fit core cooling hardware — a pump, supply lines and a heat reservoir — that routes chilled fluid to a fire‑resistant vest even if a driver chooses not to wear the vest.
- Drivers may elect not to wear the vest but those who decline will carry 0.5 kg of ballast in the cockpit to offset the missing personal equipment.
- The rule raises minimum car weights to account for the system, reported as about +2 kg for qualifying and +5 kg for the race, and teams will face packaging and reliability demands when fitting the components.
- The measure dates to changes made after the heat crises in Qatar 2023, was used earlier this season in Austria, and has prompted driver complaints about comfort, restricted movement and variable in‑race cooling that teams say they are still working to fix.