1. Standard
2. Temperature Level
3. Pressure Level
4. Condensate resistance
5. Corrosion resistance
6. Flue liner material specification
7. Soot fire resistance (O: no; G:yes)

CE MARK LABEL

Temperature Level

Max working temperature. The temperature used in the test and the resulting temperature levels achieved are as below：

As guidance, the temperature ratings applicable are:

•T200: all gas and oil applications (including condensing)

•T450: solid fuels and multifuels

•T600: power generators and CHP’s

Pressure Level

Admitted overpressure inside the flue, with its corresponding leakage rate

As guidance, the pressure ratings applicable are:

N1: natural draught installations

P1: forced draught boiler installations

H1: power generators , CHP’s and micro CHP’s

Condensate resistance

Suitability of the flue for wet or dry conditions.

D: the flue is suitable only for dry conditions. It does not resist condensate.

W: the flue is suitable whether for dry and wet conditions. It resists condensate water inside.

Corrosion resistance

Level of corrosion resistance due to the products of combustion of the different kinds of combustibles and different working conditions (dry or wet)

V1: Tested and approved as resistant to attack from products of combustion from gas.

V2: Tested and approved as resistant to attack from products of combustion from light oil (sulphur content <0,2%) and natural wood in dry conditions, and from gas in wet conditions (condensing appliances)

V3: Tested and approved as resistant to attack from products of combustion from heavy oil (sulphur content >0,2%), solid fuels and peat in dry conditions

Vm: Not tested. The manufacturer certifies only the material used in the inner wall by the quality certificate of the steel. For flues with this class there are specific regulations in each country indicating what material is suitable for each installation. As general guidance the stainless steel AISI 304 is equivalent to class V1, and the stainless steel AISI 316L is equivalent to classes V2 and V3

Flue liner material specification

The material of the inner liner must be specified and its minimum thickness as well:

After that the minimum thickness of this inner liner is specified as follows:
040:  0.4 mm
050:  0.5 mm
060:  0.6 mm

Soot fire resistance (O: no; G: yes)

Soot fire resistance and minimum distance to combustible material

It is expressed as G if the flue System has been tested, and as O if not. This classification is followed by the minimum distance (in mm) to combustible material.

The test is a thermal shock of 1.000ºC during 30 minutes during which the System must endure and the temperature of combustible materials placed at the declared distance must not exceed 100ºC at an ambient temperature of 20ºC.

The systems with O classification have not passed this test, so they cannot be used for any installation where the products of combustion contain soots (solid fuels, multifuels...). For low temperature applications, for instance room sealed boilers, where joints are used.