Transmission towers are mainly made of plates and angles. Many projects are made of standard towers which characteristics are already defined in catalogs. Otherwise, adaptations are made on already existing models. Projects for steel transmission towers can be produced with parts already in stock, there is no need to order specifically for the current project. The bill of materials of a job can be up to 6 levels (Contract, Project, Tower, Phase, Assemblies, Secondary marker). Punching is allowed to replace drilling. Welding is a rather rare operation since there are very few assemblies in this type of structures. Treatments are often galvanizing and more rarely painting. It is complex to organize the batches to be sent to the galvanizing subcontractors because the number of parts is very large and many look alike. Although manufacturing is fairly simple due to the large number of standard parts and not very complex (no assemblies for example), the logistical constraints are important for the same reason because it is necessary to sort a large number of similar parts and not make mistakes in order to deliver them on time. The standards are not very restrictive for this type of construction.