i have been asked to fit fire Extinguishers in a home but its a foster home.

with British standards legislation saying 

For any story in a building with a floor area equal to or less than 400 m² there should be

a minimum of 2 x class 'A' extinguishers with a minimum combined fire rating of 26A

this i know for businesses and property but is a foster home, so dose the 2 x 13A rule apply to a home, 

It's a private dwelling so BS5306-8 does not apply.

It's not law either and is purely guidance as it is unduly OTT in small premises.