CEN/TR 14739:2004

Scheme for carrying out a risk assessment for flammable refrigerants in case of household refrigerators and freezers

The document gives a scheme for carrying out a risk assessment for flammable refrigerants in case of house-hold refrigerators and freezers with refrigerants of group A3 according to EN 378 1, taking into consideration a sealed system and a refrigerant charge of not more than 150 g. Sealed systems are refrigerating systems in which all refrigerant containing parts are made tight by welding, brazing or similar permanent connection.
NOTE   For risk assessment the method with flow diagrams is selected, because these are helpful for checking the possible ignition of the whole appliances and to estimate the probability of ignition. It takes EN ISO 12100, EN 1050, EN 1127, EN 60335 2 24/A53, E DIN 7003 into consideration.
At least the probability of deflagration is the product of multiplication of the probability of defects of different components and the probability for the presence of explosive atmosphere and the probability for the ignition sources.

Schema für die Durchführung einer Risikobewertung für brennbare Kältemittel bei Haushalt-Kühl- und Gefriergeräten

Dieses Dokument enthält ein Schema für die Durchführung einer Risikobewertung für brennbare Kältemittel bei Haushalt-Kühl- und Gefriergeräten mit Kältemitteln der Gruppe A3 nach EN 378-1 unter Berücksichtigung einer dauerhaft geschlossenen Anlage und einer Kältemittel-Füllmenge von nicht mehr als 150 g. Dauerhaft geschlossene Anlagen sind Kälteanlagen, in denen alle kältemittelführenden Teile durch Schweißen, Hartlöten oder eine gleichwertige dauerhafte Verbindung dicht zusammengebaut sind.
ANMERKUNG   Für die Risikobewertung wird das Verfahren mit Fließbildern gewählt, da diese bei der Überprüfung möglicher Zündgefahren der Geräte insgesamt und der Abschätzung der Zündwahrscheinlichkeit sehr hilfreich sind. EN ISO 12100, EN 1050, EN 1127, EN 60335-2-24/A53, E DIN 7003 werden berücksichtigt.
Schließlich ergibt sich die Wahrscheinlichkeit einer Deflagration als das Produkt aus der Multiplikation der Wahrscheinlichkeit von Fehlern verschiedener Bauteile, der Wahrscheinlichkeit des Auftretens explosionsfähiger Atmosphäre und der Wahrscheinlichkeit des Vorhandenseins bzw. Auftretens von Zündquellen.

Schéma pour la réalisation d'une estimation des risques engendrés par les fluides frigorigènes inflammables dans les réfrigérateurs et congélateurs ménagers

Le présent document propose un plan permettant de procéder à l'évaluation des risques liés aux fluides frigorigènes inflammables dans le cas de réfrigérateurs et de congélateurs ménagers contenant des fluides frigorigènes du groupe A3 conformément à l'EN 378-1, en considérant l'étanchéité du système et une charge de fluide frigorigène inférieure ou égale à 150 g. Les systèmes étanches sont des systèmes de réfrigération dans lesquels l'étanchéité des composants contenant le fluide frigorigène est assurée par soudage, brasage ou raccord permanent similaire.
NOTE   Pour évaluer les risques, la méthode des organigrammes a été choisie. En effet, ces organigrammes sont utiles pour vérifier l'inflammation possible de l'ensemble des appareils électroménagers et estimer la probabilité d'inflammation. La méthode considère les normes EN ISO 12100, EN 1050, EN 1127, EN 60335 2 24/A53 et E DIN 7003.
La probabilité de déflagration est égale au produit de la multiplication de la probabilité de défauts des différents composants, de la probabilité de présence d'une atmosphère explosive et de la probabilité de sources d'inflammation.

Shema za izvedbo ocene tveganja za vnetljiva hladila pri gospodinjskih hladilnikih in zamrzovalnikih

General Information

• Status: Published
• Publication Date: 31-Aug-2004
• ICS: 71.100.45 - Refrigerants and antifreezes
• ICS: 97.040.30 - Domestic refrigerating appliances
• Technical Committee: CEN/TC 182 - Refrigerating systems, safety and environmental requirements
• Drafting Committee: CEN/TC 182/WG 5 - Risk assessment from the use of flammable refrigerants
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 01-Sep-2004
• Completion Date: 01-Sep-2004
• Ref Project: SIST CEN/TR 14739:2004 - Scheme for carrying out a risk assessment for flammable refrigerants in case of household refrigerators and freezers

Overview

CEN/TR 14739:2004 provides a structured scheme for carrying out risk assessments for flammable refrigerants in household refrigerators and freezers. It specifically addresses refrigerants classified as group A3 (highly flammable) under EN 378‑1, for sealed systems with a refrigerant charge of not more than 150 g. The report prescribes a flow‑diagram methodology to evaluate the likelihood of leaks, formation of explosive atmospheres and ignition leading to deflagration.

Key topics

• Scope and limits
  • Applies to household refrigerators, freezers and combinations with sealed refrigerant circuits (welded/brazed joints).
  • Charge limit: ≤ 150 g of A3 refrigerant.
• Methodology
  • Uses flow diagrams to map component failure → release → dispersion → presence of explosive atmosphere → ignition.
  • Probability of deflagration is calculated as the product of: probability of component defects × probability of explosive atmosphere × probability of ignition.
• Life‑cycle approach
  • Assessment across stages: design, construction, production, storage, transportation, operation, maintenance, service, disposal.
• Spatial analysis
  • Defines four zones (inner compartments, compressor/condensing areas, installation/ventilation spaces, surrounding room) to model leak dispersion and LFL exceedance.
• Components & defects
  • Lists typical refrigeration components (compressor, evaporator, condenser, piping, brazes, fans, heaters, solenoids, thermostats, capillary tubes) and common defect causes (material selection, brazing quality, mechanical damage, improper use).
• Ignition sources & frequency
  • Identifies household ignition sources (switches, vacuum cleaners, heaters, open flames) and incorporates duration/frequency into probability estimates.
• Quantitative examples
  • Provides example probability calculations and qualitative frequency categories (frequent, probable, occasional, remote, improbable).

Applications

• Product safety engineers performing risk assessments for domestic refrigeration designs using flammable refrigerants (e.g., isobutane/R600a).
• Manufacturers evaluating design choices (component selection, brazing, charge limits) to meet safety and regulatory expectations.
• Compliance teams preparing documentation demonstrating conformity with EN 378 and household appliance safety requirements.
• Test laboratories and certifiers using the scheme to review manufacturer risk analyses and to assess mitigation measures (ventilation, protective housings, electrical design).
• Maintenance and service organizations developing safe handling and repair procedures for appliances charged with flammable refrigerants.

Related standards

• EN 378‑1 (refrigeration safety classification and general requirements)
• EN ISO 12100, EN 1050, EN 1127 (risk assessment and explosion safety principles)
• EN 60335‑2‑24/A53 (household refrigerating appliance safety)
• E DIN 7003

Keywords: CEN TR 14739, flammable refrigerants, household refrigerators, freezers, risk assessment, A3 refrigerants, sealed systems, deflagration, lower flammability limit (LFL), EN 378.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2004
Shema za izvedbo ocene tveganja za vnetljiva hladila pri gospodinjskih hladilnikih
in zamrzovalnikih
Scheme for carrying out a risk assessment for flammable refrigerants in case of
household refrigerators and freezers
Schema für die Durchführung einer Risikobewertung für brennbare Kältemittel bei
Haushalt-Kühl- und Gefriergeräten
Schéma pour la réalisation d'une estimation des risques engendrés par les fluides
frigorigenes inflammables dans les réfrigérateurs et congélateurs ménagers
Ta slovenski standard je istoveten z: CEN/TR 14739:2004
ICS:
71.100.45 Hladiva in antifrizi Refrigerants and antifreezes
97.040.30 Hladilni aparati za dom Domestic refrigerating
appliances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 14739
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
September 2004
ICS 71.100.45; 97.040.30
English version
Scheme for carrying out a risk assessment for flammable
refrigerants in case of household refrigerators and freezers
Schéma pour la réalisation d'une estimation des risques Schema für die Durchführung einer Risikobewertung für
engendrés par les fluides frigorigènes inflammables dans brennbare Kältemittel bei Haushalt-Kühl- und
les réfrigérateurs et congélateurs ménagers Gefriergeräten
This Technical Report was approved by CEN on 25 November 2003. It has been drawn up by the Technical Committee CEN/TC 182.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 14739:2004: E
worldwide for CEN national Members.

Contents page
Foreword.3
Introduction .4
1 Scope .5
2 Mode of consideration .6
3 Appliances.7
4 Life cycles.9
5 Rooms.10
6 Components.11
7 Defects of components .11
8 Probability of component defects.12
9 Frequency of occurrence.13
10 Probability (for ignition sources and explosive atmosphere).13
10.1 Ignition sources .13
10.2 Explosive atmosphere.14
11 Deflagration/Explosion.14
12 Consequences .15
13 Flow Charts .16
13.1 General.16
13.2 Explanation of the flow charts by examples.16
14 Risk assessment.18
Foreword
This document (CEN/TR 14739:2004) has been prepared by Technical Committee CEN/TC 182 "Refrigerat-
ing systems; safety and environmental requirements", the secretariat of which is held by DIN.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Report: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lux-
embourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and
United Kingdom.
Introduction
The use of CFC and HCFC is restricted by Council Regulation 2037/2000 of the European Parliament.
Both HCs and HFCs can be used as refrigerants as well as blowing agents for insulation foams. HFC 134a is
commonly used as refrigerant but can also be used as a blowing agent for insulation foam.
The environmental advantages of HCs are obvious as the Global Warming Potential (GWP) is lower com-
pared to the GWP of HFC 134a. Therefore, a majority of household appliance manufacturers are phasing out
HFCs in favour of HCs.
Table 1 — Values for GWP — Global Warming Potentials
Emissions with impact on the global warming GWP 100 years
CFC-12 8 500
141b, HCFC   630
134a, HFC 1 300
245 fa, HFC   820
Cyclopentane, Isobutane     3
CO     1
Others (CH , N O) (24,5, 320)
4 2
With regard to the global warming impact see as well Annex B of EN 378-1:2000 (TEWI).
1 Scope
The document gives a scheme for carrying out a risk assessment for flammable refrigerants in case of house-
hold refrigerators and freezers with refrigerants of group A3 according to EN 378-1, taking into consideration a
sealed system and a refrigerant charge of not more than 150 g. Sealed systems are refrigerating systems in
which all refrigerant containing parts are made tight by welding, brazing or similar permanent connection.
NOTE For risk assessment the method with flow diagrams is selected, because these are helpful for checking the
possible ignition of the whole appliances and to estimate the probability of ignition. It takes EN ISO 12100, EN 1050,
EN 1127, EN 60335-2-24/A53, E DIN 7003 into consideration.
At least the probability of deflagration is the product of multiplication of the probability of defects of different
components and the probability for the presence of explosive atmosphere and the probability for the ignition
sources.
2 Mode of consideration
Figure 1 — Mode of consideration
Essential for the developed flow diagrams is the following mode of consideration:
First, each refrigerant containing component of a refrigerating system has to be considered for all stages of life
cycle such as design, construction, production, storage, transportation, operation, maintenance, service and
disposal. In principle it's necessary to sum up the risk assessment for each stage of life cycle. After consider-
ing the different stages of the life cycle it is necessary to consider the space in and around of the refrigerator
and freezer where a leak may occur. At least the space is separated into four different rooms (see Figure 4).
The next step of risk assessment is the estimation of possible defects of the different components. The single
probability for all possible defects have to add up to the total frequency of occurrence of the hazard. The next
step is the calculation of the probability for the presence of explosive atmosphere. And after that it's necessary
to consider the different possible ignition sources such as vacuum cleaner, fan heater, etc.
At least the probability of deflagration is the product of multiplication of the probability of defects of different
components and the probability for the presence of explosive atmosphere and the probability for the ignition
sources.
3 Appliances
Examples of the most usual refrigerating systems:
Figure 2a: System with 1 compressor and 2 compartments
Figure 2b: System with 2 compressors and 2 compartments
Figure 2c: System with 1 compressor and 1 compartment
There are refrigerators, freezers and combinations of these appliances. They can be free-standing, installa-
tions in recess areas or beneath table tops.

Key
a Fridge
b Freezing compartment
Figure 2a — System with one compressor and solenoid
Key
a Fridge
b Freezing compartment
Figure 2b — System with two compressors

Key
a Fridge/Freezing compartment
Figure 2c — System with one compressor
4 Life cycles
Important for customer and maintenance personal is transportation and storage with unpacked appliances,
operation, maintenance, service and disposal (Figure 3). Responsible for design, construction, production,
and to a certain degree for the transport and storage of packed appliances, is the manufacturer. The ad hoc
group considered transportation and operation as the most important steps of life cycle. The typical life cycle

time of a refrigerator or a freezer is 12 years .
Life cycles
- design
- construction
- production
- storage
- transportation
- operation
- maintenance
- service
- disposal
Figure 3 — Life cycles
Referring to operation it is necessary to consider the behaviour of refrigerators and freezers during "standstill"
and "operation".
The influence factors for the appliance at standstill are the ambient temperature, charge of refrigerant, oil
charge in the compressor and the inside volume of the refrigerating system. Only a quantity of refrigerant is
vaporous in the system. The remaining quantity is dissolved in the oil of the compressor.
But if the appliance is in operation it's necessary to distinguish the following situations:
• compressor is running
• compressor is switched off
In general the behaviour of a leakage depends on it's location, if lying on the high or on the low pressure side.

12 years is the pragmatical value of the manufacturers.
5 Rooms
After considering the different stages of life cycles, the next step for risk assessment is to consider the differ-
ent rooms. Because in case of a leak the space in and around the refrigerator is to be separated into four
rooms, which are represented graphically in Figure 4. Room I consists of all inner rooms of the appliance, e.g.
the fresh food storage compartment and the freezer compartment. Room II is defined as the room outside of
the housing of the appliance between the back wall and the condenser of the compressor room. Room III is
the room into which the appliance is built and the room for ventilation openings. And Room IV is the room in
the surroundings of the appliance without rooms II and III.
In case of transport room IV includes room II and room III because an ignition source is only possible in the
surroundings of the appliance (see as well Figure 4).

Figure 4 — Different rooms
6 Components
The refrigerating circuit of a refrigerator or freezer consists basically of the following components, which are
assessed by hazard under different aspects:
 one or more compressors;
 one or more evaporators;
 one or more condensors;
 dryer, filter;
 connecting pipes;
 brazed or welded connections or equal connections;
 fan;
 defrost heater;
 solenoid;
 accumulator;
 thermostat or electronic devices;
 capillary tube.
The components shall be assessed under different aspects depending on the type and material, as well as
surface protection. Thus they represent a different risk potential. Incorrect material selection or non allowable
wall thickness, unsafe installation of piping or poor connections increase the risk; more details will be found
under Clause 7.
7 Defects of components
After considering the life cycle stages and the rooms, it is necessary to consider the possible defects of a
component.
There are defects which are influenced by the manufacturer and defects influenced by the customer or service
staff. Defects of the manufacturer are for example:
 incorrect installation of pipes, susceptible to vibrations;
 non-secured parts;
 incorrect material selection, e.g. non corrosion resistant material or surface;
 bad brazed connection;
 too thin wall thicknesses;
 selection and art of component.

Defects influenced by the customer are e.g.:
 improper use - storage of explosive liquids in the appliance;
 improper defrosting;
 non-observance of the instruction manual
 incorrect installation;
 damage of evaporator/condensor by sharp objects;
 incorrect transport;
 improper disposal;
 mechanical damages.
The manufacturer shall give information about hazards due to possible incorrect use in the enclosed technical
documentation for the appliance.
8 Probability of component defects
More than 35 million refrigerators and freezers with refrigerant R 600a have been produced in Europe since
1993. Not only this time, but also the time before when the refrigerators
...