Where can you find ISO protection class codes for New Hampshire?

Call your fire department or local government. ISO (Insurance Services Office) handles inspection and rating of fire department but it is often easier to get the information from the fire department or local government. Note that your rating may be a combination of two number such as 6/9. This means that if you are within 5 files of a fire department AND 1,000 feet of a fire hydrant then the protection class is 6 but if BOTH of these don't apply then your protection class is a 9.