Difference Between IPC, UPC, ECLA, & F-index

IPC, UPC, ECLA, F-index/F-term are all systems of patent classification.  Patent classification is important to organize the granted patents into categories so patent portfolio managers and strategic firm managers can search them as prior art, and for strategic purposes.  Concordance tables can help to compare one system to another.  In all cases, class is determined by the patent examiner, not chosen by the company.


IPC (International Patent Classification System) – 70,000 divisions of the IPC, which is the native patent classification system of the World Intellectual Property Organization (WIPO).  IPC’s most general classification system consists of a letter (having 8 general classes in total), with A being human necessities. G & H are the most important and numerous high-tech general classifications for physics and electricity respectively.


UPC (USPC) (United States Patent Classification System) – The UPC is separate and not directly linked to the syntax of the IPC.  It is the native classification system of the USPTO, although all patents in the USPTO have both UPC and IPC on the front page of every patent.  The USPC syntax includes 450 general classes,  which are denoted using one, two or three digit numbers (sometimes containing a letter), and subclasses which are denoted with a two or three digit number.


ECLA (European Classification System) – This system was created due to the limitations of the IPC.   The ECLA created about 130,000 subdivisions over and above the 70,000 included in the IPC.


As you can see from the below table, the IPC subclasses use a double-digit system, while the ECLA uses a letter.  However, the more important difference is that the ECLA system uses a different technological perspective then the IPC.  The IPC is focused on the processes that are involved.  However, they ECLA focus on the contaminants that are being filtered out from the water.  This is a different perspective on classification.



F-index/F-term – This is a specific classification system for Japan.   The Japanese Patent Office devised it for internal use.  The F-index system uses the IPC classes, but then uses different coding for the sub-classes.  The F-index system uses a three-digit number followed by an additional letter for syntax of subclasses.  The F-index system includes subclasses, which are divided by process (501 & 502), and divided by materials used in the processing (503).  Therefore one F-index subclass includes can include more than one technological perspective.   For example, the below table shows the difference:



C02F9/00 – Multistep treatment of water, waste water or sewage


9/02 Involving a separation step

– 9/04 At least one step being a chemical treatment
– 9/06 Electrochemical treatment
– 9/08 At least one step being a physical treatment
– 9/10 Thermal treatment
9/12 Irradiation or treatment with electric or magnetic fields



C02F9/00 – Multistep treatment of water, waste water or sewage


– 501 . Biological processes

A Aerobic
B . Biological films
C . Activated sludge
D Anaerobic

– 502 . Non-biological processes

A Heating
B . Evaporation or condensation
C . Incineration

– 503 . Process objects

A Water
B . Pure water, ultra pure water
C Organic waste water



C02F9/00 – Multistep treatment of water, waste water or sewage


C02F9/00C Applied to waste water from the paper and cellulose industries

C02F9/00D Applied to waste water containing cyanides and chromates

– C02F9/00E Applied to waste water from the manufacture of polymers and organic compounds

– C02F9/00F Applied to waste water containing metals and metallic compounds


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