ISO 21009-2:2006

INTERNATIONAL ISO
STANDARD 21009-2
First edition
2006-10-01
Cryogenic vessels — Static vacuum
insulated vessels —
Part 2:
Operational requirements
Récipients cryogéniques — Récipients fixes isolés sous vide —
Partie 2: Exigences de fonctionnement

Reference number
ISO 21009-2:2006(E)
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ISO 21009-2:2006(E)
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ISO 21009-2:2006(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Personnel training . 2
5 General safety requirements . 3
5.1 General . 3
5.2 Safety considerations . 3
6 Installation . 3
6.1 General requirements . 3
6.2 Outdoor installation . 4
6.3 Indoor installation . 4
6.4 Safety distances . 5
7 Inspection . 6
7.1 General . 6
7.2 Inspection before putting into service . 6
7.3 Marking and labelling . 6
7.4 Handover documents . 6
7.5 Equipment . 7
7.6 Periodic inspection . 7
7.7 Inspection of pressure-relief devices . 8
8 Putting into service . 9
9 Filling . 9
10 Taking out of service . 10
11 Maintenance and repair . 10
12 Additional requirements for flammable gases . 11
12.1 General . 11
12.2 Electrical equipment . 11
12.3 Grounding (earthing) system . 11
12.4 Installation . 12
12.5 Filling . 13
12.6 Maintenance, repair and taking out of service . 13
13 Emergency equipment/procedures . 13
Annex A (informative) Safety distances . 14
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ISO 21009-2:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21009-2 was prepared by Technical Committee ISO/TC 220, Cryogenic vessels.
ISO 21009 consists of the following parts, under the general title Cryogenic vessels — Static vacuum insulated
vessels:
— Part 1: Design, fabrication, inspection and tests
— Part 2: Operational requirements
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INTERNATIONAL STANDARD ISO 21009-2:2006(E)
Cryogenic vessels — Static vacuum insulated vessels —
Part 2:
Operational requirements
1Scope
This part of ISO 21009 specifies operational requirements for static vacuum insulated vessels designed for a
0,5 bar 50 kPa
maximum allowable pressure of more than ( ). It may also be used as a guideline for vessels
designed for a maximum allowable pressure of less than 0,5 bar (50 kPa).
This part of ISO21009 applies to vessels designed for cryogenic fluids specified in EN13458-1 and
EN 13458-2.
Static cryogenic vessels are often partly equipped by the manufacturer, but may be installed or re-installed by
another party, such as the operator, user or owner. For this reason, some of the scope of this part of ISO 21009,
which includes installation, putting into service, inspection, filling, maintenance and emergency procedure,
overlaps with EN 13458-1, EN 13458-2 and EN 13458-3.
NOTE For the installation of these vessels, additional requirements can apply; these are defined in specific regulations.
2 Normative references
The following referenced documents are indispensable for the application 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 23208, Cryogenic vessels — Cleanliness for cryogenic service
EN 13458-1:2002, Cryogenic vessels — Static vacuum insulated vessels — Part 1: Fundamental requirements
EN 13458-2:2002, Cryogenic vessels— Static vacuum insulated vessels— Part2: Design, fabrication,
inspection and testing
EN 13458-3:2003, Cryogenic vessels — Static vacuum insulated vessels — Part 3: Operational requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
putting into service
operation by which a vessel is prepared to be used
NOTE It applies to either a new vessel being used for the first time or an existing vessel being returned to service.
3.2
filling
operation by which a vessel undergoes a prefill check, filling with a cryogenic fluid and an after-fill check
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ISO 21009-2:2006(E)
3.3
withdrawal
operation by which the product is taken from a vessel connected to the supply system
3.4
outdoor location
location outside of any building or structure and not enclosed by more than two walls
3.5
underground location
area or room whose ground or floor is on all sides significantly lower than the adjacent ground surfaces
NOTE Installations are to be considered on an individual basis after a suitable and sufficient risk assessment has been
carried out.
3.6
safety distance
minimum distance separating a piece of equipment from its inherent hazard that will mitigate the effect of a likely
foreseeable incident and prevent a minor incident escalating into a larger incident
NOTE The safety distance will also be determined to provide protection from foreseeable external impact (e.g. roadway,
flare) or activities outside the control of the operation (e.g. plant or customer station boundary).
3.7
gas release
escape of gas due to operating conditions, or to malfunctions that cannot be reasonably excluded
NOTE 1 Gas release for operating reasons can be produced, for example, on vent lines and pressure-release lines.
NOTE 2 Gas escape due to malfunctions which cannot be excluded can occur, for example, in the case of overfilling, failure
of fittings, loose connections, faulty operation, and leakages.
3.8
vessel
static cryogenic vessel as defined in EN 13458-1
3.9
competent person
person trained and qualified for the tasks specified in this part of ISO 21009
4 Personnel training
Only persons trained for the specific task shall be allowed to install, put into service, fill, handle, operate or
maintain the vessel.
The training programme shall include
— normal operating procedures;
— product and hazard identification;
— safe operating limits;
— emergency procedures;
— physical and chemical properties of the vessel's contents and their effects on the human body;
— personnel protective equipment (e.g. safety boots, goggles, gloves).
Training shall be repeated as necessary to ensure that personnel remain competent. A training record shall be
maintained which details the information personnel have received.
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ISO 21009-2:2006(E)
5 General safety requirements
5.1 General
Identification labels and plates shall not be removed or defaced.
Appropriate warning signs regarding product and operational hazards and personnel protective equipment
requirements shall be displayed.
Parts under pressure shall be disconnected only if they have been previously depressurized.
All surfaces which may come in contact with the product shall be kept free from oil and grease. For cleanliness
requirements, see ISO 23208.
Leaking valves or connections should be depressurized before rectification. When this is not possible, leaking
valves under pressure shall be tightened using suitable tools and procedures. Direct flame or intense heat shall
never be used to raise the pressure or de-ice frozen components.
Valve outlets shall be kept clean, dry and free from contaminants.
Vessels and their accessories shall not be modified without proper authorization.
5.2 Safety considerations
In all operations and training, the following safety considerations shall be taken into account.
— Small amounts of cryogenic fluids will produce large volumes of vaporized gas. Spillage of oxygen can
result in an oxygen-enriched atmosphere, spillage of other cryogenic fluids can result in an oxygen-deficient
atmosphere. Provision is to be made for appropriate measures for this, e.g. ventilation.
— Due to the possibility of cold embrittlement, cryogenic fluids shall not come in contact with materials (metals
or plastics) which are not suitable for low temperatures.
— Because of their extremely low temperatures, cryogenic fluids will produce cold burns when coming in
contact with the skin. Cold burns can also be produced from contact with uninsulated equipment and pipe.
— Oxygen enrichment due to liquefaction of ambient air can occur on the cold surfaces of uninsulated
equipment which contain fluids with a boiling point lower than that of oxygen.
6Installation
6.1 General requirements
Vessels shall be installed and operated in such a way that employees or third parties are not endangered.
Necessary minimum safety distances shall be observed; see also Annex A.
Vessels shall be installed so that the name plate is easily readable.
The installation should allow inspection of vessels on all sides. All vessel controls shall be capable of being
operated safely.
Vessels shall be installed in such a way that their filling operation can be carried out safely and easily.
Vessels shall be erected in such a way that no inadmissible misalignment or inclination can occur due to
— the actual foundations;
— the inherent mass of the vessel including its contents;
— external forces, e.g. seismic loads, wind loads.
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ISO 21009-2:2006(E)
Gas from pressure-relief devices or vents shall be discharged to a safe place.
Appropriate warning signs regarding product hazards shall be displayed, e.g. in rooms, areas, or on vessels.
The operating instructions shall also refer to the properties of the gas.
Vessels shall be installed in locations where there is sufficient ventilation such that the formation of dangerous
explosive gas-air mixtures or an oxygen-deficient/-enriched atmosphere is avoided.
Vessels shall be installed in such a way that adequate space is provided for maintenance and cleaning, as well
as for emergency cases.
The space for maintenance and cleaning should be at least 0,5 m around the installation.
Vessels shall not be installed in corridors, passages or thoroughfares, generally accessible lobbies, stair-wells
or near steps. Vessels should not be installed close to the aforementioned areas if traffic routes, escape routes
or accessibility are limited.
Access by unauthorized persons should be prevented.
The area/foundation under vessels, as well as below detachable connections and fittings to the liquid phase of
the vessel of oxidizing gases, shall be of non-combustible materials and free of oil, grease and other flammable
contaminants.
Consideration shall also be given to the need for similar precautions for liquid-hydrogen or liquid-helium
installations where significant air liquefaction may occur around uninsulated equipment.
NOTE To prevent a risk of brittle fracture, consideration should be given to the design temperature of the installation
downstream of the installed or fitted vapourizing system and low temperature cut-off systems, if necessary.
6.2 Outdoor installation
Vessels should be installed outdoors.
The drainage of surface water from the place of installation shall be ensured.
On sloping sites, an installation (e.g. a wall) may be necessary to prevent gas from penetrating over the place of
installation down into lower rooms, ducts, shafts or air intakes.
Vessels and their components shall be protected against mechanical damage, e.g. by vehicle buffer bars,
enclosures, safety distances. The protection of vessel supports against leaking cryogenic fluid should be
considered.
6.3 Indoor installation
If reasonable attempts to install the vessel outdoors fail, an indoor installation is permitted. Indoor installation
shall comply with the following safety precautions.
The entrance of rooms in which vessels are installed shall be labelled. Reference shall be made to the relevant
hazards of the gas.
Rooms shall
— have self-closing doors, where these do not lead directly outside;
— consist of materials which are fire resistant or non-combustible, with the exception of windows and other
closures of apertures in external walls;
— be separated from other rooms and have a fire resistance up to 30 min;
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ISO 21009-2:2006(E)
— be separated from rooms normally occupied by the public in a gas-tight manner and without any apertures;
— have adequate ventilation — gas release from the trycock valve shall be taken into account when assessing
the ventilation requirements.
Precautions/procedures shall be implemented to ensure that personnel entering or within the rooms are not
exposed to hazardous atmospheres.
Rooms containing vessels shall not be used in any other way which may be a danger to the vessels due to
mechanical effects, fire or explosion.
All fill connections, hose drains, pressure gauges, liquid level gauges, and vents necessary to fill the vessel
safely shall be fixed piping to a safe outdoor location. All pressure-relief devices shall be fixed piping to a safe
outdoor location. All piping shall be compatible for the appropriate liquid and gaseous service and designed with
no restrictions that affect the safe operation of the vessel.
All pressure-relief devices shall be designed for indoor service.
In rooms, there shall be no
— air intake openings for the ventilation of other rooms;
— open ducts;
— duct inlets unprotected against the ingress of gas;
— open shafts;
— openings to lower rooms.
6.4 Safety distances
The minimum safety distances are not intended to provide protection against catastrophic events or major
releases, which should be addressed by other means to reduce their frequency and/or consequences to an
acceptable level.
Included in safety distances are
— distance between the vessel and neighbouring installations, buildings or public roads, in order to protect the
vessel from any damage, such as heating as a result of fire or mechanical damage;
— distance between the vessel and an object outside the installation which has to be protected from the
effects of a gas release arising from normal operation.
These distances are measured from those points on a vessel from which, in the normal course of operation, a
release of product can occur, e.g. vent point, fill connection, flanges and other mechanical joints.
The safety distance is the distance, outside of which,
— in the case of flammable gases, danger through formation of an explosive atmosphere is eliminated, i.e. the
lower explosive limit (LEL) is not exceeded;
— in the case of inert and oxidizing gases, danger from oxygen deficiency or enrichment is eliminated.
The minimum safety distances defined in Annex A are based on experience and calculation of minor releases.
The safety distances may be reduced if a suitable and sufficient risk assessment is completed and documented
by the owner/operator.
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ISO 21009-2:2006(E)
7 Inspection
7.1 General
The tests and inspections shall be carried out by a competent person.
7.2 Inspection before putting into service
The inspection consists in
— checking the markings;
— checking the completeness of the handover documents;
— checking the equipment;
— checking the installation.
7.3 Marking and labelling
7.3.1 General
Marks may either be stamped on the vessel or on a durable information plate permanently attached to the
vessel. Labels attached to the vessel shall be indicated
...