Job focus : rouging in the pharmaceutical industry

STERIGENE offers different technical services so as to cater to as many clients’ needs as possible, in particular preventative and curative derouging services, cleaning process equipment parts within the pure fluid network.


What is rouging in the pharmaceutical industry?

Rouging is the red-orange discolouration that appears on the internal surfaces of process equipment from ultraclean networks, such as autoclaves, production and water for injection (WFI) distribution networks or clean steam networks.

It indicates a disturbance in the naturally present passivated layer on stainless steel metallic surfaces by the formation of iron oxides and other metallic oxides. This phenomenon leads to oxidisation in stainless steel, and this, in time, can lead to a dissemination of iron oxide in the network and therefore contaminating the pure fluids.

Rouging in the pharmaceutical industry can be divided into three classes :

  • Class I : mobile rouging, originating externally. It is wipeable, doesn’t stick to surfaces and doesn’t affect the passivated layer. Its colour varies from orange to orangey-red. The most present kind is iron oxide.
  • Class II : non wipeable rouging that sticks to surfaces. Here, the passivated layer is destabilised. The colours found are orange, red, violet and blue. The chemical form that is most present is hematite.
  •  Class III : non-wipeable rouging that has vitrified onto the surface. Its presence is linked to high temperatures and the existence of halogens. The colouration is violet and black. The form that is most present is magnetite, as well as metallic chlorides.

Regardless of the classification, rouging contaminates production batches and this leads to a loss of productivity and efficiency. There are currently no legal requirements for how to treat rouging, which is not considered a contaminant. However, so as to maintain professionalism and credibility, it is essential that companies within the pharmaceutical sector take into account and tackle this phenomenon.


Pharmaceutical Industries : what are the solutions for this phenomenon?

To combat this phenomenon, it is necessary to perform a derouging procedure. This procedure entails performing a cleaning cycle known as CIP (Clean-In-Place, not requiring dismantling) on the process equipment.

There are two types of derouging:

  • Chemical pickling
  • Electropolishing, for more extreme cases of rouging

However derouging, as a curative method, requires a relatively long procedure time, and so it has to be organised in advance. Prevention continues to be the best method, with organised and repeated treatments scheduled throughout the life of the equipment.

As experts in the engineering of clean and sterile procedures, STERIGENE provides skilled and qualified technicians to carry out STERIGENE technical services, such as curative and preventative derouging. The will carry out diagnostics and auditing on site, according to your requirements, so as to offer you the best advice and bespoke STERIGENE services.

Our Technical Services Expert, Frédéric Masse, will be present at the A3P Association Rouging / Derouging (Curative – Preventative) in Lyon on the 18th of September. This event will be full of teaching and experience feedback. Please come along and meet him to find out more about STERIGENE Technical Services, or book a meeting via the website


For all STERIGENE derouging Technical Services, please contact Frédéric MASSE by telephone at +33 1 34 44 23 30 or by email