Use of piggable pipework systems can lead to dramatic savings in investment costs and to high efficiency of the installed pipework. Emptying and washing operations are no longer necessary. Moreover, losses of valuable raw materials and finished products are avoided, the contamination waste water needing treatment, and hence the environmental burden. is reduced. A small number of pipes suffices for transport of many different substances with a high degree of separation. Pipework systems with pigging equipment in regular operation remain free from deposits. Complete automation eliminates the possibility of operating errors. However, it should not be forgotten that such a system also generates operating and maintenance costs which vary according to product. A decision to introduce a pigging System must ultimately depend upon the economics and availability of the plant.