(1) Whosoever through an offence of arson under section 306 or section 306a causes serious injury to another person or injury to a large number of people shall be liable to imprisonment of not less than two years.

(2) The penalty shall be imprisonment of not less than five years if the offender in cases under section 306a

1.  through the offence places another person in danger of death;

2.  acts with the intent of facilitating or covering up another offence; or

3.  prevents the fire from being extinguished or makes extinguishing the fire more difficult.