Standards Development

Scope

This European Standard specifies, the requirements and test methods concerning the classification and marking of gasfired central heating boilers that are fitted with atmospheric burners, fan assisted atmospheric burners and are hereafter referred to as 'boilers'. Where the word boiler is used, this is to be read as the boiler including its connecting ducts, ducts and terminals, if any.

This document is to be used in conjunction with FprEN 155021: 2021 This European Standard covers gasfired central heating boilers type B11, B11BS, B12, B12BS, B13, B13BS:

NOTE For further background information on appliance types see EN 1749:2020

a) that have a nominal heat input (on the basis of net calorific value) not exceeding 70 kW;

b) that use one or more combustible gases of the three gas families at the pressures stated in EN 437:2018;

c) where the temperature of the heat transfer fluid does not exceed 105 °C during normal operation;

d) where the maximum operating pressure in the water circuit does not exceed 6 bar;

e) which are declared in the technical instructions to be either a 'low temperature boiler' or a 'standard boiler'. If no declaration is given the boiler is to be considered a 'standard boiler';

f) which are intended to be installed inside a building or in a partially protected place;

g) which are intended to produce also hot water either by the instantaneous or storage principle, as a single unit. h) which are designed for either sealed water systems or for open water systems. For applications within the scope of the PED further requirements may be necessary (e.g. situations where the maximum allowable temperature exceeds 110 °C, or where volume times maximum allowable pressure is over 50 bar x litres).

NOTE This standard provides requirements for boilers with known constructions. For boilers with any alternative constructions, which might not fully be covered by this standard, the risk associated with this alternative construction needs to be assessed.

An example of an assessment methodology, based upon risk assessment, is given in Clause 11.

This standard does not cover all the requirements for:

i) appliances that are intended to be connected to gas grids where the quality of the distributed gas is likely to vary to a large extent over the lifetime of the appliance (see Annex AB);

j) appliances using flue dampers;

k) appliances that have a nominal heat input (on the basis of net calorific value) exceeding 70 kW;

l) appliances of the types A, B14, B2, B3, B4, B5 and C;

m) appliances intended to be connected to a (common) flue having mechanical extraction;

n) appliances with gas/air ratio control;

o) modular boilers;

p) boilers which can give rise to condensation under certain circumstances;

q) boilers intended to be installed in a room with a foreseeable negative pressure relative to the pressure in the flue system;

r) surface temperatures of external parts particular to children and elderly people;

s) appliances that are intended to burn natural gases of the second family where hydrogen is added to the natural gass;

t) boilers intended to be installed in areas accessible to elderly people and children.

NOTE Negative pressure relative to the pressure in the flue system can for example be caused by mechanical or thermal ventilation in airtight buildings.

Purpose

This revision only covers the update from the EN 155021 and an addition of an annex Z referring to the GAR.

This revision aimed not to introduce any new technical content. As some specific requirements are not covered in the EN1550221: 2012+A1:2016, the scope of EN 1550222: 2014 has been clarified, stating that this standard does not include:

1) specific requirements on surface temperatures of external parts particular to children and elderly people where relevant to ensure that this.

2) specific requirements on appliances that are intended to burn natural gases of the second family where hydrogen is added to the natural gas.

3) specific requirements for appliances equipped with an adaptive combustion control function.

This is not a change of scope, only a clarification of the existing scope.