Barreto-Naehrig (BN) curve is a well studied pairing friendly curve of embedding degree 12, that uses arithmetic in F-p12. Therefore the arithmetic of F-p12 extension field is well studied. In this paper, we have proposed an efficient approach of arithmetic operation over the extension field of degree 18 by towering. F-p18 extension field arithmetic is considered to be the basis of implementing the next generation pairing based security protocols. We have proposed to use F-p element to construct irreducible binomial for building tower of extension field up to F-p6, where conventional approach uses the root of previous irreducible polynomial to create next irreducible polynomials. Therefore using F-p elements in irreducible binomial construction, reduces the number of multiplications in F-p to calculate inversion and multiplication over F-p18, which effects acceleration in total arithmetic operation over F-p18.