Applicability of service tax

1, 2, 3 etc are builders who construct Flats & sale it to various customer & Charge Service Tax from the customers.

Mr.  A, is a person who do the work for 1, 2, 3, etc of making Steel structures which is used for making pillar & Beam. The Turnover of Mr. 1 is above 40 lacks for F.Y. 2012-13.

My question is Whether Mr. 1 is liable to pay Service Tax. And or get registered under Service Tax.