Articles 114th and 115th of the Criminal Law of People's Republic of China (PRC) stipulate:
Article 114 Whoever sets fire, breaks water, explodes, releases toxic, radioactive or infectious disease pathogens and other substances and endangers public safety, but has not caused serious consequences, shall be sentenced to fixed-term imprisonment of not less than three years but not more than 10 years.
Article 115 Whoever sets fire, breaks water, explodes, releases toxic, radioactive, infectious disease pathogens and other substances, or causes serious injury, death or heavy losses to public or private property by other dangerous means, shall be sentenced to fixed-term imprisonment of not less than 10 years, life imprisonment or death.
Whoever negligently commits the crime mentioned in the preceding paragraph shall be sentenced to fixed-term imprisonment of not less than three years but not more than seven years; If the circumstances are minor, they shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention.
Generally speaking, the plot of surrender can be used as the basis for reducing the sentence, but you should also look at the specific plot, such as what kind of consequences he caused by setting fire, how serious it is, and so on. I think you'd better find a lawyer, or you can go to Sichuan Criminal Lawyers Network for online consultation first. They must know better than I told you.