New explicit approximations to the implicitly given Colebrook equation for flow friction factor are given. They are with improved accuracy compared with the one recently published [Shaikh et al.: mt. J. Heat Mass Tran. 88 (2015) 538-5431. The new approximations are highly accurate only in rough pipes under fully developed turbulent cases of flow. (C) 2015 The Author. Published by Elsevier Ltd.