Yes, fire hazards can take place in residential and commercial buildings both. To safeguard the people and property it is better to get PFP in all high rise buildings, hospitals, shopping centres and more.
Yes, steel needs passive fire protection. Under load steel will start to buckle and move when temperatures reach 550 C and in a steel framed building this will compromise its stability and compartmentation.
Generally the Building Regulations for new build. The Fire Authority has to be consulted if refurbishment projects are to be undertaken.