When LCA is included in a production simulation model, there is a bigger need for output information to perform the calculations. To be able to allocate environmental load that origins from the facilities the product that used the facility need to be traced. Environmental load that origin form the maintenance needs to be allocated based on the machines use of the maintenance. Machines that use other resources as compressed air or other supporting machines needs to be associated to trace the usage of those resources to be able to allocate the environmental load to the products that used the machine.
Andersson, J et al. (2012)  proposed to model the machines and resources in a hierarchy. The approach is based on that all product types have attributes with weight and size. The attributes is used together with the time the product has been in each resources to allocate the environmental load to all products using the resource at the same time. A product that is using a machine is also using the machines and facilities in the upper hierarchy. The approach supports increasingly detailed modeling. The modeler increase the level of detail by model each box in greater detail in a lower lever in the hierarchy. The modeler can in other nodes stay at a brief level with less dynamics.