GROWTH – DEDICATED CALL – 10/00
TOPIC IV.5
Noise characterisation of domestic boilers
1. CONFORMITY WITH THE WORK PROGRAMME
This topic falls under the Competitive and Sustainable Growth Programme, generic
activity Measurement and testing. Specifically, it is related to Objective GROW-20006.2.1 Methodologies to support standardisation and Community policies for which
expressions of interest have been called.
Construction products directive (ref. 89/106/CEE – 21 December 88) includes noise
performance. The aim of the study Noise characterisation of domestic boilers is to
define a European method to fulfil this requirement for domestic fuel oil or gas boilers.
These boilers are sold as an assembly defined by the manufacturer between a burner and
a boiler body. Their heat input is lower than 70 kW1.
This work will allow to compare noise performance of different types of boilers and to
make easy, for customers, the choice of a silent boiler.
2. KEYWORDS
Measurements, Standard, Boiler, Heating system, Acoustic, Noise
3. SUMMARY OF OBJECTIVES AND JUSTIFICATION
Noise performance of an appliance like a boiler is its sound power level. Different
European generic measurement standard define how to determine sound power level
(for instance, EN 23 741 ‘Determination of sound power levels of noise sources Precision methods for broad-band sources in reverberation rooms’ – February 1992) but
no one is dedicated to characterise domestic fuel or gas boilers. However, to provide test
results (which would be carried out in different laboratories) allowing comparison
between different kinds of boilers and giving an answer to specific regulation, a
European method dedicated to noise test of boilers is necessary. It would define the
working conditions of the boiler and its installation during test measurement.
4. BACKGROUND
Noise performance is becoming an important information when a domestic appliance is
chosen. Today, European directives exist and require to publish sound power level for
some domestic appliances (for example dishwashers, lawn mowers, …).
1
The limitation of the heat input at 70 kW already exists for several European Standards for thermal tests
of boilers. See for instance EN297 “Gas-fired central heating boilers – Type B11 and B11BS boilers fitted
with atmospheric burners of nominal heat input not exceeding 70 kW” (October 1994).
DC 10/00/Topic IV.5/ Pg 2
For heating appliances, the evolution of the customer demand is similar. Moreover, it is
coupled with few national regulations about noise, which fix the maximum level of
noise generated by a domestic boiler. For instance, a French acoustic regulation, which
concerns acoustics in housings, is applied since January 1st 1996. It limits to 50 dB(A),
inside the kitchen, the sound pressure level generated by a domestic boiler. In the same
way, in Germany, the noise inside a bedroom, which is due to the boiler, is limited to
30 dB(A) (Appendix 2 of DIN 4109 ‘Acoustic insulation of building – Requirements
and controls’ – November 1989).
For domestic boilers2 which are sold as units (atmospheric gas boiler or assembly
comprising a boiler body and an air draught fuel oil or gas burner designed on the
production site of the manufacturer and marketed as a complete boiler), it is necessary
that manufacturers provide data that are easy to use by installers and consumers. It is
therefore necessary to measure with a harmonised procedure the sound power level of
domestic boilers. A market of approximately 4 500 000 boilers in 1998 and more than
150 manufacturers in Europe are concerned.
The existence of National regulations with specific requirements, which are not
expressed exactly on the same way and the lack of European standards can lead to
National standards which do not provide similar results and to trade barriers between
European Union member states.
That would be a paradoxical situation when the ‘Gas Appliances’ directive
(90/396/CEE – 26 July 1990) and the ‘Efficiency’ directive (92/42/CEE – 21 May
1992) which require CE marking of boilers made easier their circulation. The
measurements of thermal performance of boilers are covered by specific standards (for
instance, EN 297 ‘Central heating boiler using gaseous fioul’ –October 1994) and
several inter-comparisons have been organised in order to improve the quality of
measurement (for instance, contract n° MAT1-CT92.0009 ‘Full and part load efficiency
measurements for boilers’ funded by the European Commission under Measurement ant
Testing programme – DG XII).
In France, two specific standards have been already created to measure the sound power
level of domestic appliances:
- NF D 30 010 (April 92) for gas boiler with a heat input lower than 70 kW,
- XP D 35 010 (December 1999) for fuel oil boiler with a heat output lower than
70 kW.
Results obtained in accordance with these standards can be certified by AFNOR
(RP 247 rules applied since 1/01/2000).
In the same way, a German project (‘Measurement rules for the determination of sound
pressure level of air draught burners and associated calculation of sound power level
according to the indications of VDI2715’ April 1999) has been launched and at this
moment it is still under discussion before final publication.
We can note that similar works already exist for other building equipment. See for
instance: ISO 13261 "Sound power rating of air-conditioning and air-source heat pump
2
Boiler bodies and burners are usually sold independently for commercial heating systems and assembly
of boiler body and burner is made by the installer.
In that case, the situation is different because the boiler is installed in a dedicated room and specific
thermal and acoustic studies are carried out before the achievement of the building. This project does not
concern commercial boilers although. Measurement methods for the noise characterisation of these
boiler-burner assemblies will have to be worked out later on.
DC 10/00/Topic IV.5/ Pg 3
equipment" (April 1998) or XP ENV 12102 “ Air conditioners, heat pumps and
dehumidifiers with electrically driven compressors – Measurement of airborne noise –
Determination of the sound power level” (February 1997).
5. ECONOMIC AND SOCIAL BENEFITS
The development of National standards or methods about noise characterisation of
domestic boilers would create trade barriers between European Union member states.
Measurements according to several national standards would increase the cost of export
inside Europe for the European manufacturers and therefore the price of the boiler for
European customers. Moreover, the existence of measurement results, which are not
perfectly comparable, does not allow a fairly competition between European
manufacturers that ensure an increase of the quality of the products and of consumers
information.
The use of a European method for the noise characterisation of domestic boilers will
avoid the difficulties mentioned above and will have a positive impact for industry and
consumers.
6. SCIENTIFIC AND TECHNOLOGICAL OBJECTIVES
The aim of this work is to define a European measurement method that will be available
for noise characterisation of domestic boilers.
To achieve this goal, the following stages have to be taken into account:
 Analysis and synthesis of the National needs in relation with their specific existing
or in progress regulations. Particularly, this work has to conclude on the relevant
needed accuracy for the measurements of domestic boiler noise and on the operating
modes of boilers (heating and/or sanitary hot water production).
This first aspect is very important because, according to the required accuracy, the
European generic measurement standards (which define the general process to
determine sound power level) to use is different. On one hand, a very accurate
method would lead to an important testing cost and on the other one; a less accurate
method would lead to similar results for all boilers. A compromise between these
two aspects will have to be done.

Analysis of the technical characteristics of domestic boilers that are sold all over the
European Community. This draft will have to involve every kind of boilers: fuel oil
or gas ones, room sealed ones, atmospheric ones, equipped with an air draught
burners ones, etc …

Definition of a test method.
This work will be based on existing national standards (for example, French
standards NF D30 010 and XP D 35 010,) or national project (German VDI 2715
one for instance).

Experimental studies of the influence of working conditions and installation:
- Characteristics of the fuel: for instance, LPG or natural gas;
- Inlet/outlet water temperature;
- Type of flue gas exhaust: for instance, for room sealed boilers concentric
horizontal (C1) or vertical ( C3) pipes;
- Setting of the pump (if the boiler is equipped with): speed, pressure drop and
flow rate;
DC 10/00/Topic IV.5/ Pg 4

Setting of the fan (if the boiler is equipped with): speed, pressure drop and flow
rate;
Water static pressure;
Hydraulic connection between the tested boiler and the test rig.
Analysis of the results and definition of the final draft.
This work will be concluded by an inter-comparison between partners equipped
with relevant acoustic facilities. It will be organised in accordance with ISO 5725-2
standard ‘Accuracy (trueness and precision) of measurement methods and results –
Part 2: Basic method for the determination of repeatability and reproducibility of a
standard measurement method’ (1994).
7. TIME SCALE
Although no time scale requirements apply to this project, it is expected a 3 years
duration for achieving the described objectives.
8. IMPORTANT ADDITIONAL INFORMATION
The project should include partners with a strong expertise in boilers testing and in
acoustics.
The proposal must demonstrate that an effective collaboration with the European
association of boiler manufacturers will be ensured during the duration of the project.