Eligibility of itc

Yes,

He is eligible for ITC.

But according to Sec 17(5), ITC is not eligible for Building related products.

Yor are right, ITC would not be available

That's ok,

One more thing, Is ITC available for Fire Fighting Equipments, installed for the factory safety, and in which accounting head it will be treated.

In my view, section 17(5) is not applicable here, since there is no supply of works contract service for construction. The supply merely pertains to sheets and is  not coupled with construction. Therefore, the tax suffered on sheets is available for credit. The sheets are inputs intended for use in furtherance of business.

    Further, the ITC also avalable in respect of tax paid on Fire Fighing Equments installled in factory, since these are used in furtherance of business.