Abstract The EDGE2D-EIRENE code is applied for simulation of divertor detachment during density ramp experiments in high triangularity, L-mode plasmas in both the carbon and Be/W environments in JET. Emphasis is placed on matching experimental data (upstream and in the divertor) as far as possible. The code runs without drifts and includes either C or Be as impurity, but not W, assuming that the divertor plasma is always cold enough for the W target source to be negligible and that the W targets have to some extent been coated with Be via main chamber migration. The simulations reproduce the observed particle flux detachment as density is raised in both C and Be/W, but not the experimental in/out asymmetry. The main difference between detachment in carbon and Be/W environments is a higher upstream density required in the Be/W case to obtain similar divertor conditions to those when carbon dominates.