prEN 378-3

SLOVENSKI STANDARD
01-september-2025
Hladilni sistemi in toplotne črpalke - Varnostnotehnične in okoljevarstvene
zahteve - 3. del: Mesto postavitve in zaščita oseb
Refrigerating systems and heat pumps - Safety and environmental requirements - Part 3:
Installation site and personal protection
Kälteanlagen und Wärmepumpen - Sicherheitstechnische und umweltrelevante
Anforderungen - Teil 3: Aufstellungsort und Schutz von Personen
Systèmes frigorifiques et pompes à chaleur - Exigences de sécurité et d'environnement -
Partie 3 : Installation in situ et protection des personnes
Ta slovenski standard je istoveten z: prEN 378-3
ICS:
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 27.080; 27.200 Will supersede EN 378-3:2016+A1:2020
English Version
Refrigerating systems and heat pumps - Safety and
environmental requirements - Part 3: Installation site and
personal protection
Systèmes frigorifiques et pompes à chaleur - Exigences Kälteanlagen und Wärmepumpen -
de sécurité et d'environnement - Partie 3 : Installation Sicherheitstechnische und umweltrelevante
in situ et protection des personnes Anforderungen - Teil 3: Aufstellungsort und Schutz von
Personen
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 378-3:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 7
4 Location of refrigerating equipment . 8
4.1 General . 8
4.2 Refrigerating equipment located in the open air . 8
4.3 Refrigerating equipment located in a machinery room . 8
4.4 Refrigerating equipment located in the occupied space . 8
4.5 Refrigerating equipment located in an unoccupied space not designated a
machinery room . 9
4.6 Refrigerating equipment in location class IV . 9
4.7 Piping duct or shaft . 9
5 Machinery rooms . 9
5.1 Occupancy of machinery rooms and separate refrigeration machinery rooms . 9
5.2 Venting from or through the machinery room . 9
5.3 Combustion equipment and air compressors . 9
5.4 Open flame . 10
5.5 Storage . 10
5.6 Emergency stop . 10
5.7 Exterior openings of the machinery room . 10
5.8 Piping and ducting . 10
5.9 Normal lighting . 10
5.10 Emergency lighting . 10
5.11 Dimensions and accessibility . 11
5.12 Doors, walls and ducts . 11
5.12.1 Doors and openings . 11
5.12.2 Emergency . 11
5.12.3 Walls, floor and ceiling . 11
5.12.4 Service ducts . 11
5.12.5 Ventilation ducts . 11
5.13 Ventilation . 12
5.13.1 General . 12
5.13.2 Ventilation when machinery room is occupied . 12
5.13.3 Emergency mechanical ventilation . 12
5.13.4 Required airflow for emergency mechanical ventilation . 12
5.14 Machinery rooms for groups A2L, A2, A3, B2L, B2 and B3 refrigerants . 12
5.14.1 General . 12
5.14.2 Location . 12
5.14.3 Maximum surface temperature . 13
5.14.4 Additional requirements for R717 . 13
5.14.5 Maximum surface temperature . 14
6 Requirements for alternative provisions . 14
6.1 General . 14
6.2 Ventilation . 14
6.2.1 General . 14
6.2.2 Dilution transfer openings (air transfer openings for dilution) for natural convection 14
6.2.3 Mechanical extract ventilation . 14
6.3 Safety shut-off valves . 15
6.3.1 General . 15
6.3.2 Location . 16
6.3.3 Design . 16
7 Electrical installations . 16
7.1 General requirements . 16
7.2 Main power supply . 16
7.3 Electrical equipment in machinery rooms with refrigerating systems containing
flammable refrigerants . 16
8 Safety alarms . 17
8.1 General . 17
8.2 Alarm system power . 17
8.3 Alarm system warning . 17
8.4 Additional alarm system requirements for R717 systems with charges above 3 000 kg 17
9 Fixed refrigerant gas detectors . 17
9.1 General . 17
9.2 Type of detectors . 18
9.3 Performance of fixed gas detectors . 18
9.4 Location of detectors . 19
9.5 Maintenance . 19
10 Instruction manuals, notices and inspections . 19
10.1 Instruction manual . 19
10.2 Warning notice . 19
10.3 Visual inspection of the site . 20
11 Heat sources and temporary high temperatures at the site . 20
Annex A (informative) Personal protective equipment . 21
A.1 General requirements . 21
A.1.1 Type of protective equipment . 21
A.1.2 Accessibility . 21
A.1.3 Location . 21
A.1.4 Check and maintenance . 21
A.1.5 Temperature . 21
A.1.6 Respirators . 21
A.2 Normal use . 22
A.3 Emergency use . 22
A.3.1 General . 22
A.3.2 Respiratory protective devices . 22
A.3.3 First aid equipment . 22
Annex B (informative) Hazard duration calculation as basis for the specification of a
refrigerant gas detection system . 23
Annex C (informative) Protection for people who are inside cold rooms . 25
C.1 General . 25
C.2 Operation of doors and emergency exit doors . 25
C.3 Emergency switch or signal . 25
C.4 Cold rooms with a controlled atmosphere . 26
Bibliography . 27
European foreword
This document (prEN 378-3:2025) 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 EN 378-3:2016+A1:2020.
EN 378-3:2016+A1:2020:
Editorial changes to Clause 4 for better readability and more clarity;
— Changed heading of subclause 4.6 to "Refrigerating equipment in location class IV";
— Updated Clause 5 "Machinery rooms";
— Updated Clause 6 "Requirements for alternative provisions";
— UpdatedClause 9 "Fixed refrigerant gas detectors";
— Removed 10.4 "Maintenance of the site".
EN 378 consists of the following parts under the general title "Refrigerating systems and heat pumps
— Safety and environmental requirements":
— Part 1: Basic requirements, dèfinitions, clàssificàtion and selection criteria
— Part 2: Design, construction, testing, marking and documentation
— Part 3: Installation site and personal protection
— Part 5: Safety clàssificàtion and information about refrigerants
[1] applies for operation, maintenance, repair and recovery.
Introduction
The introduction of [2] is applicable.
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 3 of the [3] series is applicable to the installation site (plant space and services). It spècifiès
requirements on the site for safety, which can be needed because of, but not directly connected with,
the refrigerating system and its ancillary components.
This document applies:
a) to refrigerating systems, stationary or mobile, of all sizes except to vehicle air conditioning systems
covered by a spècific product standard e.g. [4];
b) to secondary cooling or heating systems;
c) to the location of the refrigerating systems;
d) to 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 of [5] are not covered by this document.
This document does not apply to goods in storage.
This document is not applicable to refrigerating systems which were manufactured before the date of
its publication, 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 for another refrigerant type, in
which case conformity with the relevant clauses of [3] parts 1, 2, 3 and 5 and [1] is assessed.
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 3864-1, Graphical symbols — Safety colours and safety signs — Part 1: Design principles for safety
signs and safety markings
ISO 7010:2019, Graphical symbols — Safety colours and safety signs — Registered safety signs
prEN 378-1, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 1:
Basic requirements, definitions, classification and selection criteria
prEN 378-1, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 1:
Basic requirements, definitions, classification and selection criteria
prEN 378-1, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 1:
Basic requirements, definitions, classification and selection criteria
prEN 378-2, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 2:
Design, construction, testing, marking and documentation
prEN 378-2 rev, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 2:
Design, construction, testing, marking and documentation
prEN 378-5, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 5:
Safety classification and information about refrigerants
prEN 378-5, Refrigerating systems and heat pumps - Safety and environmental requirements - Part 5:
Safety classification and information about refrigerants
EN 1507, Ventilation for buildings - Sheet metal air ducts with rectangular section - Requirements for
strength and leakage
EN ISO 13850:2015, Safety of machinery - Emergency stop function - Principles for design (ISO
13850:2015)
EN ISO 14122-2:2016, Safety of machinery - Permanent means of access to machinery - Part 2: Working
platforms and walkways (ISO 14122-2:2016)
EN 14624, Performance of portable locating leak detectors and of fixed gas detectors for all refrigerants
EN 14624:2020, Performance of portable locating leak detectors and of fixed gas detectors for all
refrigerants
EN 15154-5:2019, Emergency safety showers - Part 5: Water overhead body showers for sites other than
laboratories
EN 50104, Electrical equipment for the detection and measurement of oxygen - Performance requirements
and test methods
EN IEC 60079-10-1:2021, Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas
atmospheres
EN IEC 60079-10-1:2021, Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas
atmospheres
EN 60204-1:2018, Safety of machinery - Electrical equipment of machines - Part 1: General requirements
EN 60529:1991, Degrees of protection provided by enclosures (IP Code)
EN 1364, (all parts), Fire resistance tests for non-load bearing elements
EN 12236, Ventilation for buildings — Ductwork hangers and supports — Requirements for strength
EN 12845, Fixed firefighting systems — Automatic sprinkler systems — Design, installation and
maintenance
EN 50104:2019, Electrical equipment for the detection and measurement of oxygen - Performance
requirements and test methods
prEN 378-5:2026, Refrigerating systems and heat pumps - Safety and environmental requirements - Part
5: Safety classification and information about refrigerants
3 Terms, definitions and abbreviated terms
For the purposes of this document, the terms and dèfinitions given in prEN 378-1 apply.
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/
4 Location of refrigerating equipment
4.1 General
Refrigerating equipment may be sited
— outside the building in the open air;
— in a machinery room;
— in an area designated as an occupied space;
— in an area not designated as an occupied space or a machinery room.
Refrigerating equipment in location class IV shall be contained in a ventilated enclosure provided by
the manufacturer. Requirements for refrigerating equipment in location class IV are given in [6], 6.2.14.
A room, where at least one of the longer walls is open to the outside air by means of louvres with 75 %
free area and covering at least 80 % of the wall area (or the equivalent if more than one wall is to outside),
is considered as being in the open air.
The location of refrigerating systems with flàmmàblè refrigerants shall be assessed with regard to
flàmmàbility and clàssifièd according to the requirements of EN IEC 60079-10-1:2021 for the hazardous
zone. In these cases it is necessary to carry out a risk assessment with regard to flàmmàbility for the
installation site.
For flàmmàblè refrigerants, requirements regarding ignition sources in prEN 378-2, 6.2.13 shall apply
where appropriate. To determine whether a source of ignition is in a position where leaked refrigerant
could flow or stagnate, EN IEC 60079-10-1:2021 shall be used to estimate the size and extent of a
potentially flàmmàblè zone.
4.2 Refrigerating equipment located in the open air
Refrigerating systems sited in the open air shall be positioned to avoid leaked refrigerant flowing into
a building or accumulating below ground level or otherwise endangering people and property. The
refrigerant shall not be able to flow into any ventilation fresh air opening, doorway, trap door or similar
opening in the event of a leak. Where a shelter is provided for refrigerating equipment sited in the open
air it shall have natural or forced ventilation.
For refrigeration systems installed outside, in a location where a release of refrigerant can stagnate e.g.
below ground, then the installation shall comply with the requirements for fixèd refrigerant gas
detection and ventilation of machinery rooms (see 5.13, Clause 8 and Clause 9).
4.3 Refrigerating equipment located in a machinery room
When a machinery room is chosen for the location of the refrigerating equipment it shall meet the
requirements spècifièd in 5.1 to 5.14.
A risk assessment for the refrigerating system shall be conducted to determine whether it is necessary
to place the refrigerating system in a separate refrigeration machinery room.
NOTE National regulations can set spècific requirements for the use of separate refrigeration machinery rooms.
4.4 Refrigerating equipment located in the occupied space
The refrigerant charge shall be as spècifièd in prEN 378-1, Clause 7 for the access category and location
class of the equipment. Where the charge calculation is according to prEN 378-1, Clause 7.5, then the
alternative provisions listed in Clause 6 of this document shall apply.
When the concentration of the refrigerant can exceed the practical limit in accordance with prEN 378-5,
fixèd refrigerant gas detectors shall be installed and the installation in the occupied space shall
comply with Clause 8 and Clause 9 of this document.
4.5 Refrigerating equipment located in an unoccupied space not designated a
machinery room
Where compressors or pressure vessels are located in an unoccupied space which is sealed from any
occupied space the location may be treated as an occupied space in accordance with 4.4 or else it shall
be treated as a machinery room in accordance with Clause 5. Where equipment (not including
compressors and pressure vessels) containing non-permanent joints is located in an unoccupied space
which is sealed from any occupied space the requirements of Clause 5 shall be applied, but if mechanical
ventilation is required according to 5.13, ventilation shall be from an extractor hood positioned adjacent
to the equipment and the ventilation rate shall be more than 0,05 m /s per ventilator. If mechanical
ventilation is required, fixèd refrigerant gas detectors shall activate the ventilation at not more than
50 % of the ATEL, except for refrigerants with a characteristic odour at concentrations below
ATEL/ODL (such as R717), or not more than 25 % of the LFL, whichever is lower.
For any equipment, if the space cannot be sealed from any occupied space then the refrigerating
equipment shall be considered as located in the occupied space and the requirements for such spaces
shall apply.
4.6 Refrigerating equipment in location class IV
The ventilated enclosure containing the refrigerating system shall have a ventilation duct as spècifièd
by the manufacturer. ( see [6], 6.2.14). The ventilated enclosure(s) shall have sufficiènt make up air to
maintain the extract ventilation àirflow. The ventilation from the enclosure shall be discharged to open
air without endangering people or property.
4.7 Piping duct or shaft
Where hand operated shut-off devices are mounted in a piping duct or shaft designed for human entry,
the duct or shaft shall have more than one escape exit. The duct shall have a height of at least 1,2 m.
5 Machinery rooms
5.1 Occupancy of machinery rooms and separate refrigeration machinery rooms
Machinery rooms should not be used as occupied spaces. The operator shall ensure that access is
permitted only by instructed personnel undertaking maintenance in the machinery room.
A separate refrigeration machinery room shall not be used as an occupied space.
5.2 Venting from or through the machinery room
Refrigerant shall be prevented from entering neighbouring rooms, staircases, courts, gangways or
building draining systems and the escaping gas shall be vented outdoors.
There shall be no àirflow to an occupied space through a machinery room unless the air is ducted and
sealed to prevent any refrigerant leakage from entering the air stream.
5.3 Combustion equipment and air compressors
Where combustion equipment or air compressors are located in a machinery room containing
refrigerating equipment, the combustion air supply for combustion equipment or the supply air for air
compressors shall be ducted from outside in such a manner as to prevent any refrigerant from entering
the air intake.
5.4 Open flame
Open (naked) flàmès shall not be permitted in machinery rooms, except for welding, brazing or similar
activity and then only provided the refrigerant concentration is monitored and adequate ventilation is
ensured. Such open flàmès shall not be left unattended.
5.5 Storage
Machinery rooms shall not be used for storage with the exception of tools, spare parts and compressor
oil for the installed equipment.
NOTE National regulations can apply for the storage of refrigerants, or flàmmàblè or toxic materials.
5.6 Emergency stop
A remote switch for stopping the refrigerating system shall be provided outside the room, near to the
machinery room door.
5.7 Exterior openings of the machinery room
Exterior openings shall not be situated within 2 m of building emergency exit staircases or other building
openings, e.g. windows, doors, ventilation inlets.
5.8 Piping and ducting
All piping and ventilation ducting that passes through walls, ceiling and floors of machinery rooms, shall
be sealed where it passes through the walls, ceiling or floors. The sealing shall have at least the same
firè resistance as the walls, ceiling or floor.
Discharge pipes from relief devices may diffuse the charge into the air by adequate means but away
from any air intake to the building or may discharge into an adequate quantity of a suitable absorbing
material.
Relief devices for refrigerants in group A1 may discharge into the machinery room provided the system
charge is less than the limits set in [2], Clause 7. Such discharges of refrigerant shall take place so that
persons and property are not endangered.
5.9 Normal lighting
Fixed lighting shall be selected and positioned in spaces containing refrigerating equipment to provide
adequate illumination for safe operation.
NOTE National regulations can apply for the illumination level and location.
Filament light bulbs shall be protected by “splash safe“ covers in accordance with EN 60529:19911
IPX 4 in machinery rooms containing R717 refrigerating systems.
5.10 Emergency lighting
A fixèd or portable emergency lighting system shall be provided, adequate to allow operation of controls
and evacuation of personnel, when normal lighting fails.
NOTE National regulations can apply for the illumination level and location.
As impacted by EN 60529:1991/A2:2013/AC:2019-02:2019
5.11 Dimensions and accessibility
The dimensions of the machinery room shall allow easy installation and sufficiènt room for service,
maintenance, operation, repair and disassembly of the refrigerating equipment, including sufficiènt
space for persons carrying emergency equipment and wearing personal protective equipment.
If necessary, catwalks and fixèd ladders shall be provided in order to avoid standing or walking on
piping, fittings, their supports and supporting structures and on components during the operation,
maintenance, inspection and repair of the refrigerating system.
There shall be clear headroom of at least 2,1 m below equipment situated over gangways and permanent
workplaces. The requirements for work staging shall be according to EN ISO 14122-2:2016.
5.12 Doors, walls and ducts
5.12.1 Doors and openings
Machinery rooms shall have doors opening outward and sufficiènt in number to ensure persons can
escape in an emergency.
The doors shall be tight fitting and self-closing. They shall be so designed that they can be opened from
inside (anti-panic system). The doors shall have at least a 30-minutes firè resistance construction, using
materials and construction tested in accordance with EN 1364. There shall be no openings that permit
unintended passage of escaping refrigerant, vapours, odours and all other gases to other parts of the
building.
NOTE Requirements regarding firè resistive construction of doors and openings can be provided in local
regulations.
5.12.2 Emergency
Provision shall be made to facilitate immediate exit from the machinery room in the event of an
emergency.
At least one emergency exit shall open directly to the open air, or it shall lead to an emergency exit
passageway.
5.12.3 Walls, floor and ceiling
Walls, floor and ceiling between the machinery room and the rest of the building shall have at least a
1 h firè resistive construction and be tightly sealed.
NOTE Requirements regarding firè resistive construction of walls, floor and ceiling can be provided in local
regulations.
5.12.4 Service ducts
A service duct is any sealed conduit, culvert, trench, duct or passageway containing pipes or cables,
whether they are part of the refrigeration system installation or not. Service ducts shall be sealed to
minimize escaped refrigerant leakage into the service duct, and shall have at least the same firè
resistance as walls and doors.
Service ducts, including walkways and crawl spaces, containing piping for refrigerants shall be vented
to a safe place to prevent a dangerous accumulation of refrigerant in the event of a leak.
5.12.5 Ventilation ducts
Sheet metal for normal and emergency ventilation ducts shall be in accordance with EN 1507 and
supported as required by EN 12236. After erection all duct seams and joints shall be sealed to minimize
gas leakage from the duct. The ventilation duct shall have at least the same firè resistance as the doors
and walls of the machinery room.
5.13 Ventilation
5.13.1 General
The ventilation of machinery rooms shall be sufficiènt for background ventilation (if required),
temperature control under normal operating conditions, occupancy and emergencies.
If emergency mechanical ventilation is installed, air from machinery rooms shall be vented outdoors in
the event of a release of refrigerant due to leaks or rupture of components. This ventilation system shall
be independent of any other ventilation system on the site. The fan shall be placed so that during
operation the air ducts installed in the machine room operate under negative pressure.
Provision shall be made for a sufficiènt supply of outside replacement air and a good distribution of that
air over the machinery room avoiding dead zones.
Openings for exhaust from the machinery room to the outside shall be positioned to avoid re-circulation
into the room.
5.13.2 Ventilation when machinery room is occupied
Ventilation shall be a minimum of 4 air changes per hour when the machinery room is occupied. In the
event that the necessary ventilation rate cannot be achieved an audible and/or visual alarm shall be
initiated and, where relevant, electrical supplies shall be terminated.
5.13.3 Emergency mechanical ventilation
Where the refrigerant charge exceeds the practical limit multiplied by the volume of in the machinery
room, the emergency mechanical ventilation system shall be activated by a fixèd refrigerant gas
detector(s), located in the machinery room. The fixèd refrigerant gas detector(s) shall be as spècifièd
in Clause 9.
There shall be at least two independent emergency controls, one or more located outside the machinery
room and one or more inside the machinery room.
5.13.4 Required airflow for emergency mechanical ventilation
The emergency mechanical ventilation for the machinery room shall achieve an air change rate of at
least 15 air changes per hour in the part of the room in which the refrigeration system is installed. The
emergency mechanical ventilation system shall be installed to ensure that effective air change in the
location of the equipment is achieved, for example by positioning the extract duct close to the equipment
and on the opposite side to the source of supply air.
5.14 Machinery rooms for groups A2L, A2, A3, B2L, B2 and B3 refrigerants
5.14.1 General
Machinery rooms with group A2L, A2, B2L, B2, A3, B3 refrigerants shall be assessed with regard to
flàmmàbility and clàssifièd according to the requirements of EN IEC 60079-10-1:2021 for the
hazardous zone.
NOTE The assessment according to [7] considering the LFL and type of release can conclude that the hazardous
area is of negligible extent. Refrigerant leak mass flow rates can be based on Annex H of [2].
Refer to Clause 7 for requirements regarding electrical installation.
5.14.2 Location
5.14.2.1 General
Local and national regulations can apply for the location of the machinery room.
5.14.2.2 Emergency exhaust ventilation
The emergency exhaust ventilation fan shall be either:
a) in the air flow with the motor outside the àirflow, or
b) rated for hazardous areas as required in EN IEC 60079-10-1:2021.
The fan shall be located to avoid pressurization of the exhaust ductwork in the machinery room.
The fan shall not cause sparks to occur if it contacts the duct material.
The outlet from the exhaust ventilation shall not be restricted but have means of keeping rubbish, leaves
and birds from entering. The bottom of any rising ductwork open to the outside shall have a drain with
a trap for rainwater and with access for inspection.
For doors communicating to other areas inside the building and where the fixèd refrigerant gas detector
is not able to detect refrigerants when these doors are opened, emergency ventilation shall be initiated
when a door is opened for more than 60 s.
5.14.3 Maximum surface temperature
Hot surfaces shall not exceed a temperature of 100 K less than the auto-ignition temperature of the
refrigerant.
5.14.4 Additional requirements for R717
5.14.4.1 Drainage
To prevent R717 spill reaching surface waters, a catchment system shall be designed and installed. The
machinery room floor shall be designed in order to prevent liquid R717 from spilling out from the room.
The drain from the catchment system shall be normally closed.
5.14.4.2 Fire sprinkler systems
If firè suppression systems of the water sprinkler type are installed in machinery rooms with R-717
refrigerating systems then the following conditions shall be fulfillèd:
— the sprinkler heads are individually actuated at 141 °C or higher (high temperature according to
EN 12845);
— there is no manual override of the activation of the sprinkler system;
— the sprinkler installation conforms to the requirements of to EN 12845.
NOTE 1 The addition of water to a pool of ammonia liquid can cause the rapid evolution of large amounts of
ammonia gas in the atmosphere resulting in increased risk of injury to persons in the vicinity.
NOTE 2 A pre-action system where an actuated water valve in the sprinkler supply is controlled by a firè
detection system can be used to reduce the probability of accidental discharge of any of the sprinkler heads.
NOTE 3 The provision for a remote sump in the drainage system from the machinery room will reduce the risk
of environmental pollution from the run-off water.
5.14.4.3 Doors and openings
Machinery rooms where the refrigerant charge is above the practical limit for the volume of the room
shall have a door that either opens directly to the outside air or through a dedicated anteroom equipped
with self-closing, tight-fitting doors to an emergency exit passageway.
5.14.5 Maximum surface temperature
Hot surfaces shall not exceed a temperature of 80 % of the auto-ignition temperature (in °C) or 100 K
less than the auto-ignition temperature of the refrigerant, whichever is higher.
6 Requirements for alternative provisions
6.1 General
These additional requirements only apply to intrinsic design systems described in prEN 378-1, 7.5.
If the extrinsic design method is used these measures can be applied.
6.2 Ventilation
6.2.1 General
[2], 7.4., may require employing ventilation as a safety measure.
Ventilation shall be made to a place where sufficiènt air is available to dilute the leaked refrigerant such
as outdoors or a large occupied space. The indoor place used to provide ventilation air shall have
sufficiènt volume, including the volume of the room in which the indoor unit is installed to ensure that
the quantity limit is not exceeded.
6.2.2 Dilution transfer openings (air transfer openings for dilution) for natural convection
Dilution transfer openings shall be provided in both high and low level locations. This area may be
divided into two or more openings in each high and low location. These shall be located near the floor
and near the ceiling respectively. If the ceiling is suspended and the wall is not provided between the
next rooms above the ceiling then the upper opening is not necessary.
The lower edge of the lower opening shall be a height of 0,2 m or less from the floor. The upper edge of
the upper opening shall be equal to or higher than the upper edge of the door opening.
6.2.3 Mechanical extract ventilation
6.2.3.1 Required airflow
The minimum ventilation àirflow required to dilute and extract released refrigerant depends upon the
room volume, releasable refrigerant quantity, the refrigerant type and certain equipment installation
characteristics.
NOTE 1 The rate of increase in minimum àirflow diminishes with greater releasable refrigerant quantity since
for the assumed leak mass flow rate the greater quantity only results in a prolon
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