Full steam ahead
with a clean boiler


Prevent future problems with Clean Steel’s comprehensive Boiler Assessment.

We will use the findings to create a written report including images.

Effective fouling and corrosion management ensure that boilers run properly and efficiently. Clean Steel’s Boiler Assessment helps you to define the rate of fouling on heat exchange surfaces and identify the problem areas. Accumulations of relatively small amounts of fouling can reduce boiler efficiency significantly and increase the need for sweeping and fuel consumption.

Clean Steel’s Boiler Assessment is realised on the basis of a visual inspection carried out by Clean Steel’s project manager during a maintenance shutdown. The inspector’s findings are then analysed with the material in Clean Steel’s database (corresponding boiler type, size and fuelling) and compiled into a written report with images.

The report includes:

  • verbal description of the current condition of the boiler and its different parts with regard to fouling,
  • fouling rate on a CS fouling scale,
  • cleaning recommendation for the boiler,
  • expected benefits of the proposed cleaning recommendation with regard to, for example, reduced fuel costs and improved steam production.


A scale describing the boiler’s fouling rate which helps the customer to gain a comprehensive view of the boiler’s current condition and cleaning needs.


All heat exchange surfaces are 100% clean.
  • Inspection-ready. Corresponds to the cleanness of a new boiler.
  • The boiler runs properly, and the energy production level is excellent.
  • Cleaning recommendation: maintaining this level by cleaning the boiler during annual shutdown.

Incipient fouling

Relatively small amounts of localised fouling.
  • The boiler runs properly only with high-quality fuel.
  • Boiler efficiency is still good.
  • Cleaning recommendation: cleaning the superheater area to maximise boiler efficiency and ensure proper operation.


Fouling found on several parts of the boiler.
  • Adequate amount of fouling, often a “mossy” and/or a sintered, hard fouling layer of 2-4 mm on the heat exchange surface.
  • The boiler may still run properly, but steam production has decreased due to fouling. Fuel consumption often increased.
  • Corrosion often hidden under the fouling.
  • Cleaning recommendation: cleaning the superheater area and backflow, at the least. If time allows, cleaning the entire boiler is recommended.

Very fouled

The entire boiler is fouled.
  • Boiler often has specific problem areas (e.g. superheater or economiser) which are heavily fouled and in danger of becoming clogged.
  • The top layer of fouling is often soft and easily removable. A hard, sintered fouling layer is often found under the soft, crumbling layer of fouling.
  • Reduced steam/energy production due to fouling.
  • Increased fuel consumption.
  • Problems of corrosion and erosion are common.
  • Cleaning recommendation: cleaning the entire boiler.

Extremely fouled

The entire boiler is heavily fouled.
  • The boiler has blockages which have reduced boiler efficiency significantly.
  • Increasing risk of emergency shutdown.
  • Steam/energy production has decreased significantly, fuel consumption often high.
  • Cleaning recommendation: thorough cleaning of the entire boiler.

Would you like to know more?

We would gladly help you to improve your boiler’s efficiency. Contact us!



If you value efficient and smooth operations.

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Clean Steel

Friitalantie 11, FI-28400 Ulvila FINLAND

+358 10  526 2053

Invoicing address: 
Clean Steel Pori Oy
PL 1527

E-invoice address (OVT code): TE003724140278
Forwarder code: 003701011385