Forward energy measurement with CMS

Energy flow is measured in the forward region of CMS at pseudorapidities up to 6.6 in pp interactions at 13 TeV with forward (HF) and very forward (CASTOR) calorimeters. The results are compared to model predictions. The CMS results at different centre-of-mass energies are compared using the pseudorapidity variable shifted by the beam rapidity, thus studying applicability of the hypothesis of limiting fragmentation