Modular plants offer the opportunity to save time and reduce development costs for market introduction of new products and processes. When designing process plants, sizing of equipment, process lines and the overall plant is determined by the process. Taking into account scale-up factors which vary per process and type of industry most plants will have their own scale to be built at. Based on this vast variety in size and type of projects, it may be concluded that a standard module size that matches the process requirements in most cases is hard to determine. In this article an overview will be presented of different modular plant cases and the basis for standardizing these modular plants.