What are the four classes of fire according to nfpa?

According to the NFPA, the five classifications of fire are:

"Class A: result from ordinary combustible materials, including wood, cloth, paper, and many plastics.

Class B: burn in flammable liquids, combustible liquids, petroleum greases, oils, alcohols, and flammable gases.

Class C: involve energized electrical equipment.

Class D: fires in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium.

Class K: fires in cooking appliances that involve combustible cooking media, such as vegetable or animal oils and fats"

what is the tax base for the sales tax?

it should be (usually ) 6%