I will illustrate an example in which techniques employed in QCD global analyses for the determination of parton distribution functions of the proton (PDFs) are used to constrain properties of particles predicted by extensions of the Standard Model. If such particles can, in principle, produce signatures at hadron colliders, some of their properties can be constrained independently of other information on such states. In particular, I will focus on color-octet fermions (gluinos from supersymmetry). I will show how light color-octet fermions are disfavored in the framework of CT10NLO PDF global analysis. These techniques are very general and are utilized as a powerful tool to constrain several aspects of Physics Beyond the Standard Model at new generation hadron colliders.