prEN 378-1

SLOVENSKI STANDARD
01-september-2025
Hladilni sistemi in toplotne črpalke - Varnostnotehnične in okoljevarstvene
zahteve - 1. del: Osnovne zahteve, definicije, razvrstitev in kriteriji za izbiro
Refrigerating systems and heat pumps - Safety and environmental requirements - Part 1:
Basic requirements, definitions, classification and selection criteria
Kälteanlagen und Wärmepumpen - Sicherheitstechnische und umweltrelevante
Anforderungen - Teil 1: Grundlegende Anforderungen, Begriffe, Klassifikationen und
Auswahlkriterien
Systèmes frigorifiques et pompes à chaleur - Exigences de sécurité et d'environnement -
Partie 1 : Exigences de base, définitions, classification et critères de choix
Ta slovenski standard je istoveten z: prEN 378-1
ICS:
01.040.27 Prenos energije in toplote Energy and heat transfer
(Slovarji) engineering (Vocabularies)
27.080 Toplotne črpalke Heat pumps
27.200 Hladilna tehnologija Refrigerating technology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2025
ICS 01.040.27; 27.080; 27.200 Will supersede EN 378-1:2016+A1:2020
English Version
Refrigerating systems and heat pumps - Safety and
environmental requirements - Part 1: Basic requirements,
definitions, classification and selection criteria
Systèmes frigorifiques et pompes à chaleur - Exigences Kälteanlagen und Wärmepumpen -
de sécurité et d'environnement - Partie 1 : Exigences Sicherheitstechnische und umweltrelevante
de base, définitions, classification et critères de choix Anforderungen - Teil 1: Grundlegende Anforderungen,
Begriffe, Klassifikationen und Auswahlkriterien
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 182.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 378-1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
3.1 Refrigerating systems . 7
3.2 Occupancies, locations . 10
3.3 Pressures . 11
3.4 Components of refrigerating systems . 11
3.5 Piping and joints . 14
3.6 Safety accessories . 15
3.7 Fluids . 16
3.8 Miscellaneous . 20
4 Symbols and abbreviated terms . 20
5 Classification . 24
5.1 General . 24
5.2 Classification of system locations . 24
5.2.1 General . 24
5.2.2 Class I – Mechanical equipment located within the occupied space . 24
5.2.3 Class II – Compressors and pressure vessels outside the occupied space . 25
5.2.4 Class III – Entire refrigerating system in machinery room or open air . 25
5.2.5 Class IV – Ventilated enclosures . 25
5.3 Classification of access to occupied spaces, machinery rooms, and open air . 25
5.4 Classification of refrigerants . 27
6 Determining the room volume and floor area used in refrigerant quantity safety
limit calculation . 27
6.1 General . 27
6.2 Connected spaces calculations . 27
6.3 Space size for ducted systems . 28
7 Determining the releasable quantity of refrigerant and the refrigerant quantity
safety limit . 28
7.1 General . 28
7.2 Establishing the releasable quantity of refrigerant, m . 29
rq
7.3 Defining factors for toxicity and flammability . 29
7.4 Establishing the refrigerant quantity safety limit, m . 29
sl
7.4.1 General . 29
7.4.2 Quantity limit based on toxicity . 30
7.4.3 Quantity limit based on flammability . 31
7.5 Options for calculation of refrigerant quantity safety limits . 32
7.5.1 General . 32
7.5.2 Determination of the concentration factor F . 33
7.5.3 Determination of the representative height h* . 33
7.5.4 Determination of toxicity quantity limit m . 33
tl
7.5.5 Determination of m and A . 34
fl min
7.5.6 Surrounding concentration test . 35
7.5.7 Required air flow rates to justify the increase of concentration factors of Table 7 . 35
7.5.8 Quantity limit based on flammability for class IV ventilated enclosure . 36
7.6 Additional requirements for spaces below ground . 36
7.7 Special requirements for ice rinks . 36
Annex A (informative) Equivalent terms in English, French and German . 37
Annex B (informative) Total equivalent warming impact (TEWI) . 41
Annex C (informative) Examples of classification in Clause 5 . 43
Annex D (normative) Special requirements for ice rinks . 44
D.1 Indoor ice rinks . 44
D.2 Outdoor ice rinks and installations for similar sporting activities . 44
Annex E (informative) Potential hazards for refrigerating systems . 45
Annex F (informative) Calculation examples related to 7.5 . 47
F.1 Example 1 for 7.5 . 47
F.2 Example 2 for 7.5 . 47
F.3 Example 4 for 7.5 . 47
Annex G (informative) Estimation of leak mass flow rates . 49
G.1 General . 49
G.2 Leakage during operation . 49
G.3 Leakage during adverse operating conditions . 51
G.4 Leakage during maintenance operations . 51
Annex H (informative) Test and calculation methods for determining releasable charge m . 52
rc
H.1 General . 52
H.2 Determination of releasable charge by a simulated leak into a space . 52
H.2.1 Test set-up . 52
H.2.2 Test method . 53
H.2.3 Calculated orifice size . 54
H.3 Determination of releasable charge by a simulated leak without venting to the
atmosphere . 54
H.3.1 Test setup . 54
H.3.2 Test method . 55
H.4 Determination of releasable charge by calculation and test . 55
H.4.1 General . 55
H.4.2 Refrigerant release between detection and closing the safety shut-off valves . 56
H.4.3 Determination of m . 56
r3
H.5 Determining the time before the leak is detected, t . 58
r1
H.5.1 General . 59
H.5.2 Determination of t by default time . 59
r1
H.5.3 Example to determine t based on effective room concentration for refrigerating
r1
systems using A1 and A2L refrigerants . 59
H.6 Test conditions for releasable charge limited systems . 59
H.7 Methods for determining the releasable charge based on latent heat or sublimation . 60
H.7.1 General . 60
H.7.2 Determination by calculation . 60
Annex I (normative) Refrigerant quantity safety limit or minimum room area
determination using surrounding concentration test . 62
I.1 General . 62
I.2 Room arrangement . 62
I.3 Simulated leak . 63
I.4 Concentration measurements . 63
I.5 Acceptance criteria . 64
Annex J (normative) Calculations for refrigerant-containing parts are within an enclosure
with openings . 65
J.1 Determining the concentration factor for enclosures with openings . 65
J.2 Determining the effective release height for enclosures mounted at a specific height . 65
Annex K (normative) Stagnation effect with of higher molar mass refrigerants . 67
Bibliography . 68
European foreword
This document (prEN 378-1:2025) has been prepared by Technical Committee CEN/TC 182
"Refrigerating systems, safety and environmental requirements", the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede [1].
— Clause 5 was restructured.
— The examples of systems were removed from Clause 5,
— Clause 6 and Clause 7 were combined to a new Clause 6.
— Annex C (Location and refrigerant charge limitations) was converted into a new Clause 7 of the
main body of the standard (Determining the releasable quantity of refrigerant and the refrigerant
quantity safety limit).
— The concept of releasable quantity of refrigerant was introduced in a new subclause 7.2.
— Options for calculation of refrigerant quantity safety limits were introduced in a new subclause 7.5.
— Additional requirements for spaces below ground are introduced in new subclause 7.6.
— Annex E was converted into a new [2].
— Annex H with examples related to Annex C were converted to and informative Annex F with
examples related to 7.5.
— Examples related to Clause 5 were given in a new Annex C.
— Annex F and Annex G were named Annex D and Annex E.
— New informative Annex G for assumed mass flow rates.
— New informative Annex H for test and calculation methods for determining releasable charge m .
rc
— New normative Annex I for refrigerant quantity safety limit or minimum room area determination
using surrounding concentration test.
— New normative Annex J for calculations for refrigerant-containing parts are within an enclosure
with openings.
— New normative Annex K for stagnation effect with of higher molar mass refrigerants
[3] consists of the following parts under the general title “Refrigerating systems and heat pumps —
Safety and environmental requirements”:
—    Part 1: Basic requirements, definitions, classification and selection criteria;
—    Part 2: Design, construction, testing, marking and documentation;
—    Part 3: Installation site and personal protection;
—    Part 5: Safety classification and information about refrigerants.
[4] applies for operation, maintenance, repair and recovery.
Introduction
This document relates to safety and environmental requirements in the design, manufacture,
construction, installation, operation, maintenance, repair and disposal of refrigerating systems
regarding local and global environments. It does not relate to the finàl destruction of the refrigerants.
It is intended to minimize possible hazards to persons, property and the environment from refrigerating
systems and refrigerants. These hazards are associated with the physical and chemical characteristics
of refrigerants and the pressures and temperatures occurring in refrigeration cycles.
Attention is drawn to hazards such as excessive temperature at compressor discharge, liquid slugging,
erroneous operation and reduction in mechanical strength caused by corrosion, erosion, thermal stress,
liquid hammer or vibration. Corrosion deserves special consideration as conditions peculiar to
refrigerating systems arise due to alternate frosting and defrosting or the covering of equipment by
insulation.
The extent to which hazards are covered is indicated in Annex E. In addition, machinery should comply
as appropriate with [5] for hazards which are not covered by this document.
Commonly used refrigerants except R717 are heavier than air. Care should be taken to avoid stagnant
pockets of heavy refrigerant vapours by proper location of ventilation inlet and exhaust openings.
Refrigerants and their combinations with oils, water or other substances, can affect the system
chemically and physically. They can, if they have detrimental properties, endanger persons, property
and the environment when escaping from the refrigerating system. Refrigerants are selected with due
regard to their potential influèncè on the global environment (ODP, GWP) as well as their possible effects
on the local environment. Evaluation of the environmental performance requires a life cycle approach.
With regard to global climate change the Total Equivalent Warming Impact approach is generally used
as the basis (see Annex B). Reference should be made to the [6] to address other environmental aspects.
Many factors influèncè environmental impacts such as:
—    location of the system;
—    energy èfficièncy of the system;
—    type of refrigerant;
—    service frequency;
—    refrigerant leaks;
—    sensitivity of charge on èfficièncy;
—    minimization of heat load;
—    control methods.
Additional investments may be directed towards reducing leaks, increasing energy èfficièncy or
modifying the design in order to use a different refrigerant. A life cycle approach is necessary to identify
where additional investments will have the most bènèficiàl effects.
1 Scope
This document spècifiès the requirements for the safety of persons and property, provides guidance for
the protection of the environment and establishes procedures for the operation, maintenance and repair
of refrigerating systems and the recovery of refrigerants.
The term “refrigerating system” used in this document includes heat pumps.
This part of EN 378 spècifiès the clàssificàtion and selection criteria applicable to refrigerating systems.
These clàssificàtion and selection criteria are used in Parts 2, 3 and 5.
This document applies to:
a) refrigerating systems, stationary or mobile, of all sizes except to vehicle air conditioning systems
covered by a spècific product standard e.g. [7];
b) secondary cooling or heating systems;
c) the location of the refrigerating systems;
d) replaced parts and added components after adoption of this document if they are not identical in
function and in the capacity.
Systems using refrigerants other than those listed in Part 5 of this standard are not covered by this
document.
Clause 7 spècifiès how to determine the refrigerant quantity safety limit in a given space, which, when
exceeded, requires additional protective measures to reduce the risk.
This document is not applicable to refrigerating systems which were manufactured before the date of
its publication as a European Standard except for extensions and modificàtions to the system which
were implemented after publication.
This document is applicable to new refrigerating systems, extensions or modificàtions of already
existing systems, and for existing stationary systems, being transferred to and operated on another site.
This document also applies in the case of the conversion of a system to another refrigerant type, in which
case conformity to the relevant clauses of Parts 1, 2, 3 and 5 of the standard is expected to be assessed.
Product family standards dealing with the safety of refrigerating systems take precedence over
horizontal and generic standards covering the same subject.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
ISO 5149-4:2022, Refrigerating systems and heat pumps — Safety and environmental requirements —
Part 4: Operation, maintenance, repair and recovery
IEC 60335-2-40:2022, Household and similar electrical appliances - Safety - Part 2-40: Particular
requirements for electrical heat pumps, air-conditioners and dehumidifiers
EN 378-3, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 3:
Installation site and personal protection
prEN 378-3 rev, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 3:
Installation site and personal protection
EN 378-4:2016, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 4:
Operation, maintenance, repair and recovery
prEN 378-5, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 5:
Safety classification and information about refrigerants
EN 14276-2:2020, Pressure equipment for refrigerating systems and heat pumps - Part 2: Piping - General
requirements
EN 14624:2020, Performance of portable locating leak detectors and of fixed gas detectors for all
refrigerants
EN ISO 14903:2017, Refrigerating systems and heat pumps - Qualification of tightness of components and
joints (ISO 14903:2017)
EN ISO 22712:2023, Refrigerating systems and heat pumps - Competence of personnel (ISO 22712:2023)
EN IEC 60079-10-1:2021, Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas
atmospheres
EN IEC 60335-2-89:2022, Household and similar electrical appliances - Safety - Part 2-89: Particular
requirements for commercial refrigerating appliances and ice-makers with an incorporated or remote
refrigerant unit or motor-compressor
prEN 378-3:2025, Refrigerating systems and heat pumps - Safety and environmental requirements - Part
3: Installation site and personal protection
prEN 378-5:2024, Refrigerating systems and heat pumps - Safety and environmental requirements - Part
5: Safety classification and information about refrigerants
prEN 378-5:2026 Refrigerating systems and heat pumps - Safety and environmental requirements -
Part 5: Safety clàssificàtion and information about refrigerants
3 Terms and definitions
For the purposes of this document, the following terms and dèfinitions apply.
NOTE See informative Annex A for equivalent terms in English, French and German.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1 Refrigerating systems
3.1.1
refrigerating system
heat pump
combination of interconnected refrigerant-containing parts constituting one closed circuit in which the
refrigerant is circulated for the purpose of extracting and delivering heat (i.e. cooling and heating)
3.1.2
self-contained system
complete factory-made refrigerating system in a suitable frame and/or enclosure, that is fabricated and
transported complete, or in two or more sections and in which no refrigerant-containing parts are
connected on site other than by isolation valves, such as companion valves
3.1.3
unit system
self-contained system that has been assembled, fillèd ready for use and tested prior to its installation
and is installed without the need for connecting any refrigerant-containing parts
Note 1 to entry: A unit system can include factory assembled companion valves.
3.1.4
limit charged system
refrigerating system in which the internal volume and refrigerant charge are such that, with the system
idle, the allowable pressure will not be exceeded when complete evaporation of the refrigerant occurs
3.1.5
sorption system
refrigerating system in which refrigeration is effected by evaporation of a refrigerant, the vapour then
being absorbed or adsorbed by an absorbent or adsorbent medium respectively, from which it is
subsequently expelled at a higher partial vapour pressure by heating and then liquèfièd by cooling
3.1.6
secondary cooling or heating system
system employing a fluid which transfers heat from the product or spaces to be cooled or heated or
from another cooling or heating system to the refrigerating system without compression and expansion
of the fluid
3.1.7
sealed system
refrigerating system in which all refrigerant containing parts are made tight by welding, brazing or a
similar permanent connection which may include capped valves and capped service ports that allow
proper repair or disposal, and which have a tested leakage rate of less than 3 grams per year under a
pressure of at least a quarter of the maximum allowable pressure
Note 1 to entry: Joints based on mechanical forces which are prevented from improper use by the need of a special
tool (e.g. by glue) are considered as a similar permanent connection.
Note 2 to entry: Hermetically sealed systems in [8] are equivalent to sealed systems in EN378–2.
3.1.8
technically tight system
refrigerating system or part of system which meets the spècifièd level of tightness
Note 1 to entry: The spècifièd level of tightness is the level of tightness tested in accordance with the requirements
for tightness testing in Clause 6 of [9].
3.1.9
durably technically tight system
refrigerating system or part of system that is shown to be technically tight and that remains technically
tight due to its design, or the technical tightness of which is ensured by means of maintenance and
supervision
Note 1 to entry: A refrigerating system or part of system is shown to be technically tight by testing according to
Clause 6 of [9].
Note 2 to entry: No release is to be expected from equipment that is durably technically tight.
Note 3 to entry: Equipment that is durably technically tight does not cause any hazardous areas in its surroundings
while it is closed.
Note 4 to entry: Durably technically tight equipment includes for example semihermetic compressors,
semihermetic pumps, welded or brazed connections and detachable connections which are rarely detached in
operation, such as weld-lip seal flàngès or tongue and groove flàngès.
3.1.10
part of the refrigerating system
several components assembled together and exposed to the same pressure in operation or pressure
source, respectively, as determined by the manufacturer
Note 1 to entry: The dèfinitions and describe the most common configuràtions.
3.1.11
high pressure side
part of a refrigerating system operating at approximately the condenser or gas cooler pressure
3.1.12
low pressure side
part of a refrigerating system operating at approximately the evaporator pressure
3.1.13
mobile system
refrigerating system which is usually in transit during operation
Note 1 to entry: Mobile systems include refrigerated cargo systems in ships, refrigerating systems in fishing boats,
air conditioning on board, and transport of refrigerated cargo by road, train and containers.
3.1.14
cascade system
two or more independent refrigeration circuits where the condenser of one circuit rejects heat directly
to the evaporator of another
3.1.15
transcritical system
refrigerating system where the compressor discharges refrigerant at a pressure above the critical point
3.1.16
assembly
several components assembled to constitute an integrated and functional whole
Note 1 to entry: Assemblies are often connected together on-site to make a complete refrigerating system.
3.1.17
component
individual functional item of a refrigerating system
3.1.18
fixed refrigerating system
refrigerating system that is intended to be used while fastened to a support or while secured in a spècific
location
3.1.19
operating state
function that the refrigerating system is in at a spècific time during normal operation
EXAMPLE        standby, cooling mode, heating mode and defrosting
3.1.20
pressure equipment
components of the refrigerating system, clàssifièd as pressure vessels according to dèfinition , piping
including its accessories (e.g. valves) according to dèfinition 3.5, and safety accessories according to
dèfinition 3.6
3.1.21
releasable charge limited system
refrigerating system in which the releasable charge is limited by design measures
3.1.22
safety shut-off valve
valve for the purpose of limiting the amount of releasable charge
3.1.23
potential leak point
any point in the refrigerating system that is judged to be a weak point
Note 1 to entry: Potential leak points can include parts under stress or vibration.
3.1.24
intrinsic design method
design principle where the safety of persons or property with respect to leakage of refrigerant is ensured
by measures inherent in the design and manufacture of the equipment that comprises the
refrigerating system
Note 1 to entry: Limiting the charge of the system to a quantity that cannot give rise to an unsafe condition, including
integral àirflow in the unit to ensure that leaked refrigerant cannot stagnate and incorporating refrigerant gas
detection in the controls of the indoor unit are examples of intrinsic design method.
3.1.25
extrinsic design method
design principle where limiting the charge of refrigerant in a system or part of a system is not the primary
method of ensuring the safety of persons or property with respect to leakage of refrigerant from the
system
Note 1 to entry: Systems constructed on site using components from several equipment manufacturers and co-
ordinated by a system designer will require an extrinsic design method.
3.1.26
ducted system
refrigerating systems where air is directly ducted to the spaces and refrigerant-containing parts are
within the ducted àirflow
3.1.27
indirect circuit
closed circuit containing heat exchangers that are in direct contact with the substance to be treated
3.2 Occupancies, locations
3.2.1
machinery room
enclosed room or space, with mechanical ventilation, sealed from public areas and not accessible to the
public, which is intended to contain components of the refrigerating system
Note 1 to entry: The room may only be entered by authorised persons.
Note 2 to entry: A machinery room can contain other equipment provided design and its installation requirements
are compatible with the requirements for the safety of the refrigerating system.
3.2.2
separate refrigeration machinery room
machinery room intended to contain only components of the refrigerating system, accessible only to
competent personnel for the purposes of inspection, maintenance and repair
Note 1 to entry: Where the standard refers to the term machinery room, separate refrigeration machinery rooms
are included.
3.2.3
occupied space
space in a building which is bounded by walls, floors and ceilings and which is occupied by persons for
a significànt period
Note 1 to entry: Where the spaces around the apparent occupied space are, by construction or design, not air tight
with respect to the occupied space, these may be considered as part of the occupied space. above; e.g. false ceilings
voids, crawl ways, ducts, movable partitions and doors with transfer grilles or undercut doors.
3.2.4
hallway
corridor for the passage of people
3.2.5
exit
opening in the outer wall, with or without a door or gate
3.2.6
exit passageway
passageway immediately in the vicinity of the exit through which people leave the building
3.2.7
cold room
room maintained by a refrigerating system at a temperature lower than ambient temperature
3.2.8
open air
unenclosed space, possibly but not necessarily roofed
3.2.9
crawl space
space that is in general accessed for maintenance only and where it is not possible to walk or access
by walking
Note 1 to entry: Usually, the height of crawl spaces is less than 1 m.
3.2.10
ventilated enclosure
enclosure containing the refrigerating system that does not enable air to flow from the enclosure to the
surrounding space and has a ventilation system that produces àirflow from the enclosures to the open
air through a ventilation duct
3.3 Pressures
3.3.1
maximum allowable pressure
PS
maximum pressure for which the system or component is designed for, as spècifièd by the manufacturer
Note 1 to entry: PS is the limit which should not be exceeded whether the system is working or not.
Note 2 to entry: The Pressure Equipment Directive 2014/68/EU [10] designates the maximum allowable pressure
as the symbol “PS”.
3.4 Components of refrigerating systems
3.4.1
refrigerating installation
assembly of components of a refrigerating system and all the apparatus necessary for its operation
3.4.2
refrigerating equipment
components forming a part of the refrigerating system
EXAMPLE        compressor, condenser, generator, absorber, adsorber, receiver, evaporator, surge drum
3.4.3
compressor
device for mechanically increasing the pressure of a refrigerant vapour
3.4.4
motor-compressor
fixèd combination of electrical motor and compressor in one unit
3.4.4.1
hermetic motor-compressor
combination of a compressor and electrical motor, both of which are enclosed in the same housing, with
no external shaft or shaft seals
3.4.4.2
semi-hermetic motor-compressor
accessible hermetic motor-compressor
combination consisting of a compressor and electrical motor, both of which are enclosed in the same
housing, having removable covers for access, but having no external shaft or shaft seals
3.4.5
open compressor
compressor having a drive shaft penetrating the refrigerant-tight housing
3.4.6
positive displacement compressor
compressor in which compression is obtained by changing the internal volume of the compression
chamber
3.4.7
non-positive displacement compressor
compressor in which compression is obtained without changing the internal volume of the
compression chamber
3.4.8
pressure vessel
any refrigerant-containing component of a refrigerating system other than:
— coils (including their headers) consisting of pipes with air as secondary fluid;
— piping and its valves, joints and fittings;
— control devices;
— pressure switches, gauges, liquid indicators;
— pressure relief valves, fusible plugs, bursting discs;
— equipment comprising casings or machinery where the dimensioning, choice of material and
manufacturing rules are based primarily on requirements for sufficiènt strength, rigidity and
stability to meet the static and dynamic operational effects or other operational characteristics and
for which pressure is not a significànt design factor. Such equipment may include pumps and
compressors.
Note 1 to entry: The semi-hermetic and open type compressors used in refrigerating systems can be subject to
the exclusion Article 1.2.j of Directive 2014/68/EU [10] by referring to the working party group guidelines WPG
1/11, 1/12 and 2/34. The compressor manufacturer needs to decide on the basis of a case by case assessment, if
the exclusion Article 1.2.j of Directive 2014/68/EU [10] is applicable.
Note 2 to entry: This dèfinition is aligned to Directive 2014/68 EU [10].
3.4.9
condenser
heat exchanger in which refrigerant vapour is liquèfièd by removal of heat
3.4.10
gas cooler
heat exchanger in a transcritical system in which supercritical refrigerant is cooled by removal of heat
3.4.11
receiver
vessel permanently connected to a system by inlet and outlet pipes for accumulation of liquid refrigerant
3.4.12
accumulator
vessel capable of holding liquid refrigerant and permanently connected between the exit of the
evaporator and suction of the compressor
3.4.13
evaporator
heat exchanger in which liquid refrigerant is vaporised by absorbing heat from the substance to be
cooled
3.4.14
coil or grid
component of the refrigerating system constructed from pipes or tubes suitably connected and serving
as a heat exchanger (e.g. evaporator or condenser)
3.4.15
compressor unit
combination of one or more compressors and associated components
3.4.16
condensing unit
combination of one or more compressors, condensers, receivers (when required) and the associated
components
3.4.17
surge drum
vessel containing refrigerant at low pressure and temperature and connected by liquid feed and vapour
return pipes to one or more evaporators
3.4.18
internal net volume
volume calculated from the internal dimensions of a vessel, and excluding the volume of the permanent
internal parts
3.4.19
type approved component
component for which examination is performed on one or more samples of this component in
accordance with a recognized standard for type approval
3.5 Piping and joints
3.5.1
piping
piping such as pipes or tubes (including hoses, bellows, fittings, or flèxiblè pipes) for interconnecting
the various components of a refrigerating system
Note 1 to entry: This dèfinition of piping is piping covered in the scope of EN 14276-2:2020.
3.5.2
joint
connection made between two parts
3.5.3
welded joint
joint obtained by the joining of metal parts in the plastic or molten state
3.5.4
brazed joint
joint obtained by the joining of metal parts with alloys which melt at temperatures higher than 450 °C
but less than the melting temperatures of the joined parts
3.5.5
flanged joint
joint made by bolting together a pair of flàngèd ends
3.5.6
flared joint
metal-to-metal compression joint in which a conical spread is made on the end of the tube
3.5.7
compression joint
joints which achieve tightness by deforming a compressing ring
3.5.8
taper pipe thread joint
pipe joint with tapered threads that achieves tightness with filling material or deformation of thread
mount
3.5.9
header
pipe or tube component of a refrigerating system to which several other pipes or tubes are connected
3.5.10
shut-off device
device to shut off the flow of the fluid, e.g. refrigerant, brine
3.5.11
companion valves
pairs of mating stop valves, isolating sections of systems and arranged so that these sections may be
joined before opening these valves or separated after closing them
3.5.12
isolating valves
valves which prevent flow in either direction when closed
3.5.13
locked valve
valve sealed or in other ways constrained, so that it can only be operated by a competent person
3.5.14
nominal size
DN
numerical designation of size which is common to all components in a piping system other than
components indicated by outside diameters or by thread size
Note 1 to entry: It is a convenient round number for reference purposes and is only loosely related to manufacturing
dimensions. The nominal size is designated by DN followed by a number.
3.6 Safety accessories
3.6.1
pressure relief device
PRD
device designed to relieve excessive pressure automatically
3.6.2
pressure relief valve
PRV
pressure a
...