EN 13799:2022
(Main)LPG equipment and accessories - Contents gauges for Liquefied Petroleum Gas (LPG) pressure vessels
LPG equipment and accessories - Contents gauges for Liquefied Petroleum Gas (LPG) pressure vessels
This document specifies minimum requirements for design and testing of contents gauges, which are directly connected to LPG transportable pressure vessels, LPG drums, LPG cylinders and static LPG pressure vessels above 0,5 l water capacity excluding those used for automotive containers.
This document includes minimum requirements for the safe interchangeability of telemetry equipment, which is either integral in or additional to the contents gauge.
This document does not apply to refineries or other process plants.
Flüssiggas-Geräte und Ausrüstungsteile - Füllstandsanzeiger für Druckbehälter für Flüssiggas (LPG)
Dieses Dokument legt Mindestanforderungen an Auslegung und Prüfung von Füllstandsanzeigern fest, die direkt mit ortsbeweglichen Druckbehältern, Druckfässern, Flaschen und ortsfesten Druckbehältern für Flüssiggas mit einem Fassungsraum über 0,5 l verbunden sind, mit Ausnahme jener zur Verwendung für Autogastanks.
Dieses Dokument enthält Mindestanforderungen an die sichere Austauschbarkeit von Telemetrieausrüstung, die entweder fester oder zusätzlicher Bestandteil des Füllstandsanzeigers ist.
Dieses Dokument gilt nicht für Raffinerien oder andere verfahrenstechnische Anlagen.
Equipements pour GPL et leurs accessoires - Jauges de niveau pour les réservoirs de gaz de pétrole liquéfié (GPL)
Le présent document spécifie les exigences minimales relatives à la conception et aux essais des jauges de niveau directement reliées à des réservoirs de GPL mobiles sous pression, à des fûts de GPL, à des bouteilles de GPL et à des réservoirs de GPL fixes sous pression, d'une capacité en eau supérieure à 0,5 l, à l'exception de celles utilisées pour les réservoirs d'automobiles.
NOTE Les jauges de niveau conformes au présent document sont conçues, le cas échéant, pour répondre aux Exigences essentielles de sécurité, 2.2.2, point 2, de la Directive 2014/68/UE [1].
Le présent document inclut des exigences minimales pour l'interchangeabilité en toute sécurité des appareils de télémesure qui sont soit intégrés à la jauge de niveau, soit complémentaires à celle-ci.
Le présent document ne s'applique pas aux raffineries ou autres usines de traitement.
Oprema in pribor za utekočinjeni naftni plin (UNP) - Kazalniki nivoja v posodah za UNP
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2022
Nadomešča:
SIST EN 13799:2012
Oprema in pribor za utekočinjeni naftni plin (UNP) - Kazalniki nivoja v posodah za
UNP
LPG equipment and accessories - Contents gauges for Liquefied Petroleum Gas (LPG)
pressure vessels
Flüssiggas-Geräte und Ausrüstungsteile - Füllstandsanzeiger für Druckbehälter für
Flüssiggas (LPG)
Équipements et accessoires GPL - Jauges de niveau pour les réservoirs de gaz de
pétrole liquéfié (GPL)
Ta slovenski standard je istoveten z: EN 13799:2022
ICS:
23.020.10 Nepremične posode in Stationary containers and
rezervoarji tanks
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 13799
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2022
EUROPÄISCHE NORM
ICS 23.020.01 Supersedes EN 13799:2012
English Version
LPG equipment and accessories - Contents gauges for
Liquefied Petroleum Gas (LPG) pressure vessels
Equipements pour GPL et leurs accessoires - Jauges de Flüssiggas-Geräte und Ausrüstungsteile -
niveau pour les réservoirs de gaz de pétrole liquéfié Füllstandsanzeiger für Druckbehälter für Flüssiggas
(GPL) (LPG)
This European Standard was approved by CEN on 8 August 2022.
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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13799:2022 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
4 Operating conditions . 9
5 Materials . 9
5.1 General . 9
5.2 Metallic materials . 9
5.3 Non-metallic components . 10
5.4 Lubricants, sealants and adhesives . 10
6 Design – General requirements . 11
6.1 General . 11
6.2 Seals . 11
6.3 Springs . 11
6.4 Threads . 11
6.5 Flanges . 12
7 Design – Specific requirements . 12
7.1 Contents gauge . 12
7.1.1 Float gauge . 12
7.1.2 Rotary gauge . 13
7.1.3 Fixed liquid level gauge . 13
7.1.4 Slip tube gauge . 13
7.2 Dials for contents gauges . 13
7.3 Telemetry . 14
7.3.1 General . 14
7.3.2 Specific requirements . 14
7.3.3 Interchangeability . 14
8 Design type testing . 16
8.1 General . 16
8.2 Over-torquing deformation test . 17
8.3 External tightness test . 18
8.4 Internal tightness test . 18
8.5 Accuracy test . 19
8.5.1 General . 19
8.5.2 Float gauges . 19
8.6 Endurance test . 19
8.7 Gauge repeatability . 20
8.8 Pressure strength test . 20
8.9 Stress cracking test . 20
8.9.1 General . 20
8.9.2 Mercurous nitrate immersion test . 21
8.9.3 Moist ammonia air stress cracking test . 21
8.10 Float pressure test . 21
8.11 Dimensional inspection . 21
8.12 Function test . 21
8.13 Vacuum test . 21
8.14 Float test. 21
8.14.1 Resistance to gas . 21
8.14.2 Resistance to condensate/liquid phase of combustible gases . 22
8.15 Dial insert pressure test . 22
9 Production testing and inspection . 23
10 Marking . 23
11 Documentation . 23
Annex A (normative) Float gauge flange and gasket nominal dimensions . 24
Annex B (normative) Special low temperature requirements . 27
Annex C (normative) Production testing and inspection . 28
C.1 General . 28
C.2 Production testing . 28
C.3 Batch testing . 28
C.4 Rejection criteria . 28
C.5 Finishing operations . 29
Annex D (informative) Vibration testing . 30
D.1 General . 30
D.2 Test samples . 30
D.3 Test method . 30
D.4 Criteria for passing the test . 30
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/68/EU aimed to be covered . 31
Bibliography . 33
European foreword
This document (EN 13799:2022) has been prepared by Technical Committee CEN/TC 286 “Liquefied
petroleum gas equipment and accessories”, the secretariat of which is held by NSAI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2023, and conflicting national standards shall be
withdrawn at the latest by April 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 13799:2012.
The main changes compared to the previous edition include:
— revision to operational conditions;
— introduction of requirements for rubber material;
— introduction of telemetry requirements;
— introduction of an accuracy test;
— introduction of gauge repeatability requirements.
This document has been submitted for reference in:
— the RID [2]; and
— the technical annexes of the ADR [3].
NOTE These regulations take precedence over any clause of this document. It is emphasized that RID/ADR are
being revised regularly at intervals of two years which might lead to temporary non-compliances with the clauses
of this document.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s) / Regulation(s).
For relationship with EU Directive(s) / Regulation(s), see informative Annex ZA, which is an integral part
of this document.
For the purposes of this document, contents gauges are considered a pressure accessory in accordance
with the Pressure Equipment Directive 2014/68/EU [1] in that they have a function additional to that of
containing pressure.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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 the United
Kingdom.
Introduction
Provisions are restricted to a general guidance. Limit values are specified in national laws. It is
recommended that companies using this document develop an environmental management policy. For
guidance see the ISO 14000 series.
Protection of the environment is a key political issue in Europe and elsewhere. For TC 286 this is covered
in CEN/TS 16765 [4] LPG equipment and accessories - Environmental considerations for CEN/TC 286
standards, and this Technical Specification should be read in conjunction with this document. This
Technical Specification provides guidance on the environmental aspects to be considered regarding
equipment and accessories produced for the LPG industry and the following is addressed:
a) design;
b) manufacture;
c) packaging;
d) use and operation; and
e) disposal.
In this document the unit bar is used, due to its universal use in the field of technical gases. It should,
however, be noted that bar is not an SI unit, and that the corresponding SI unit for pressure is Pa
5 5 2
(1 bar = 10 Pa = 10 N/m ).
NOTE Pressure values given in this document are given as gauge pressure (pressure exceeding atmospheric
pressure) unless otherwise stated.
1 Scope
This document specifies minimum requirements for design and testing of contents gauges, which are
directly connected to LPG transportable pressure vessels, LPG drums, LPG cylinders and static LPG
pressure vessels above 0,5 l water capacity excluding those used for automotive containers.
This document includes minimum requirements for the safe interchangeability of telemetry equipment,
which is either integral in or additional to the contents gauge.
This document does not apply to refineries or other process plants.
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.
EN 549:2019, Rubber materials for seals and diaphragms for gas appliances and gas equipment
EN 751-1:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases
and hot water — Part 1: Anaerobic jointing compounds
EN 751-2:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases
and hot water — Part 2: Non-hardening jointing compounds
EN 751-3:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases
and hot water — Part 3: Unsintered PTFE tapes
EN 1092-1:2018, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 1: Steel flanges
EN 1563:2018, Founding — Spheroidal graphite cast irons
EN 1774:1997, Zinc and zinc alloys — Alloys for foundry purposes — Ingot and liquid
EN 12164:2016, Copper and copper alloys — Rod for free machining purposes
EN 12165:2016, Copper and copper alloys — Wrought and unwrought forging stock
EN 12420:2014, Copper and copper alloys — Forgings
EN 12516-1:2014+A1:2018, Industrial valves — Shell design strength — Part 1: Tabulation method for
steel valve shells
EN 12516-4:2014+A1:2018, Industrial valves — Shell design strength — Part 4: Calculation method for
valve shells manufactured in metallic materials other than steel
EN 13445-2:2021, Unfired pressure vessels — Part 2: Materials
EN 13906-1:2013, Cylindrical helical springs made from round wire and bar — Calculation and design —
Part 1: Compression springs
EN IEC 60079-0:2018, Explosive atmospheres — Part 0: Equipment — General requirements
(IEC 60079-0:2017/COR1:2020)
EN ISO 7049:2011, Cross-recessed pan head tapping screws (ISO/FDIS 7049:2011)
EN ISO 11114-1:2020, Gas cylinders — Compatibility of cylinder and valve materials with gas contents —
Part 1: Metallic materials (ISO 11114-1:2020)
EN ISO 11114-2:2021, Gas cylinders — Compatibility of cylinder and valve materials with gas contents —
Part 2: Non-metallic materials (ISO 11114-2:2021)
ISO 301:2006, Zinc alloy ingots intended for castings
ISO 1817:2015, Rubber, vulcanized or thermoplastic — Determination of the effect of liquids
ISO 2859-1:1999, Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by
acceptance quality limit (AQL) for lot-by-lot inspection
ISO 6957:1988, Copper alloys — Ammonia test for stress corrosion resistance
ANSI/ASME B1.20.1 - 2013, Pipe threads, general purpose (inch); issued by American National Standards
Institute in 2013
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
liquefied petroleum gas
LPG
low pressure gas composed of one or more light hydrocarbons which are assigned to UN 1011, UN 1075,
UN 1965, UN 1969 or UN 1978 only and which consists mainly of propane, propene, butane, butane
isomers, butene with traces of other hydrocarbon gases
3.2
contents gauge
device to indicate the liquid level or contents in a pressure vessel
3.2.1
float gauge
device to indicate the content of a vessel by means of a float on the liquid surface within the vessel
This document is impacted by EN IEC 60079-0:2018/AC:2020-02.
3.2.2
rotary gauge
device which operates through a rotating action in order to assess the liquid level in a vessel by means of
temporarily venting a limited amount of LPG, whereupon the change from liquid to vapour is detected
3.2.3
fixed liquid level gauge
control device which indicates the predetermined liquid level when there is a change in vented LPG from
vapour to liquid
EXAMPLE A dip tube in combination with a vent valve.
3.2.4
slip tube
device which operates through a linear action in order to assess the liquid level in a pressure vessel by
means of temporarily venting a limited amount of LPG, where upon the change from liquid to vapour is
detected
3.3
external leak tightness
resistance to leakage through the fitting to or from the atmosphere
3.4
internal leak tightness
resistance to leakage to atmosphere across the valve seal or any other pressure containing component
when the valve is closed
3.5
maximum allowable pressure
maximum pressure for which the equipment is designed
3.6
nominal diameter
DN
numerical designation of size, in millimetres, which is common to all components in a piping system other
than components designated 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.
3.7
pressure vessel
assembly of the pressure-retaining envelope (including the openings and their closures) and non-
pressure-retaining parts attached directly to it
3.8
type test
test or series of tests conducted to prove that the design meets the requirements of this document
4 Operating conditions
Contents gauges designed in accordance with this document shall be suitable for the following conditions:
— a minimum operating temperature of −20 °C;
— a minimum operating temperature of −40 °C for those parts of Europe where contents gauges are
subject to more severe temperature conditions. The material and design shall be shown to be
satisfactory for operations under these conditions and shall meet the requirements of Annex B;
— the maximum operating temperature is 65 °C; and
— the minimum pressure to which a gauge is normally exposed is 0 bar gauge. Vacuum conditions on
the gauge, arising from butane at low temperature or evacuation of the pressure vessel can expose
the device to a vacuum of 0,05 bar absolute.
The maximum allowable pressure for a contents gauge shall be 30 bar.
5 Materials
5.1 General
5.1.1 All materials in contact with LPG shall be physically and chemically compatible with LPG under
all the normal operating conditions for which the contents gauge is intended to be used.
5.1.2 Materials for gauge components shall be selected to give adequate strength in service. Materials
selected shall adequately protect against other modes of failure such as atmospheric corrosion, brass
dezincification, stress corrosion or other material failure.
5.1.3 Alternative materials to those listed in 5.2 are not precluded, providing they comply with a
standard or specification that ensures control of chemical and physical properties, and quality
appropriate to the end use.
5.1.4 Dial inserts shall be sealed to prevent water ingress into the dial insert. The contents gauge shall
be designed to ensure that water ingress between the dial insert and gauge body is avoided or does not
interfere with the gauge operation if it freezes. This may include filling any void with suitable material or
the provision of a drain hole not less than 2,5 mm diameter.
5.1.5 Optional equipment directly connected to the gauge shall not affect the integrity of the gauge and
its function.
5.2 Metallic materials
5.2.1 Metallic materials for gauges shall be steel, stainless steel, copper alloys, aluminium alloys, or zinc
alloys in accordance with EN ISO 11114-1:2020.
5.2.2 Shell materials shall be selected in accordance with EN 12516-1:2014+A1:2018,
EN 12516-4:2014+A1:2018 or EN 13445-2:2021.
5.2.3 Materials for steel flanges shall be in accordance with EN 1092-1:2018. Propane steel flanges shall
have a pressure rating of PN 40.
5.2.4 Stainless steel for components shall contain not less than 16 % chromium, and not less than 6 %
nickel.
5.2.5 Springs shall be manufactured from stainless steel wire and shall contain not less than 16 %
chromium and not less than 6 % nickel.
5.2.6 Hot stamped brass shall be non-porous and suitable for machining or other processing. Leaded
brass shall be CW614N in accordance with EN 12164:2016 or CW617N in accordance with
EN 12420:2014 and EN 12165:2016. Sand-cast brass shall not be used. Cold drawn brass rods shall only
be used for machining after adequate testing for internal cracking, porosity or other inclusions and shall
be heat treated if required. Components produced from stamping brass shall not exhibit cold shuts also
known as folds, or surface defects.
5.2.7 Components manufactured from hot stamped brass or contents gauge bodies made of drawn
brass or machined from brass rod shall be capable of withstanding, without cracking, the stress cracking
test in accordance with 8.9.
5.2.8 Spheroidal graphite cast iron shall comply with EN 1563:2018 and amendments, with an
elongation at fracture of more than 18 %. Other ductile irons or cast irons shall not be used.
5.2.9 ZnAl4 and ZnAl4Cu1 shall be in accordance with ISO 301:2006 or EN 1774:1997.
5.2.10 Castings shall be free from inclusions and surface defects which could adversely affect the
strength, leak tightness or performance of the contents gauge.
5.3 Non-metallic components
5.3.1 Non-metallic materials shall be in accordance with EN ISO 11114-2:2021.
5.3.2 Except for floats, all non-metallic materials in contact with LPG shall not distort, harden or adhere
to the body or seat face to such an extent as to impair the function of the gauge.
5.3.3 Rubber materials, with the exception of floats, in contact with LPG, for temperatures of –20 °C
(−40 °C for low temperature applications) to +65 °C, shall meet the requirements of EN 549:2019 for
resistance to:
a) gas (n-pentane test);
b) lubricants;
c) ageing;
d) compression;
e) ozone (where the material is exposed to the atmosphere);
f) condensate/liquid phase of combustible gases (liquid B test).
5.3.4 The buoyancy of the float shall not be adversely affected by the LPG. Non-metallic floats shall be
tested in accordance with 8.14 for resistance to gas and for resistance to condensate/liquid phase of
combustible gases.
5.4 Lubricants, sealants and adhesives
Where used on threads and seals; lubricants, sealants, and adhesives shall be compatible with LPG and
not interfere with the operation of the contents gauge. Sealants shall comply with EN 751-1:1996,
EN 751-2:1996 or EN 751-3:1996.
6 Design – General requirements
6.1 General
6.1.1 Moving parts shall have sufficient clearance to ensure freedom of movement under all normal
conditions of service. Means of guidance shall be provided to ensure correct operation.
6.1.2 All components necessary for the correct function of the device shall be secured to prevent
unintentional disassembly during normal operation.
6.1.3 Contents gauges shall be designed to ensure external and internal leak tightness, and their
function shall not be affected, as a result of vibration during transportation.
6.1.4 The design shall take account of the use of dissimilar materials, e.g. electrochemical corrosion or
material expansion.
6.1.5 Electrical equipment, when an integral part of the contents gauge, is expected to be ATEX
compliant in accordance with Directive 2014/34/EU and shall be either explosion proof or intrinsically
safe, and shall meet the requirements of EN IEC 60079-0:2018 where appropriate.
6.1.6 Contents gauges shall include all of the components necessary for their normal function and
installation on the pressure vessel.
6.1.7 Possible stress corrosion shall be eliminated by either design or heat treatment.
6.1.8 The design of the contents gauge should take account of the following:
— minimizing the use of materials;
— fittings required for the pressure vessel;
— minimizing the environmental impact of in-service maintenance and end of life disposal;
— efficient transport of finished product; and
— any packaging and protection used during storage/transport of the finished product should be
selected to have the minimum environmental impact, i.e. use of recyclable or bio-degradable
materials, minimum use of energy.
6.2 Seals
Seals shall be attached or otherwise assembled such that they will not become dislocated under service
conditions. Dynamic seals shall not be secured solely by the application of adhesive.
6.3 Springs
Springs shall be designed in accordance with EN 13906-1:2013.
6.4 Threads
6.4.1 Taper threaded pressure vessel connections shall comply with ANSI/ASME B1.20.1 - 2013.
Thread sizes shall not exceed DN 50 (2 inches).
6.4.2 Where taper threads are used, the design shall ensure that over-torquing shall not impede the
correct operation of the contents gauge, see 8.2.
6.4.3 Taper threaded sections of a body designed for a pressure vessel connection shall be constructed
with wrenching flats.
6.4.4 All threads other than taper threaded pressure vessel connections shall be in accordance with a
European Standard (EN) or an International Standard (ISO), or should be in accordance with
ANSI/ASME B1.20.1 - 2013.
6.4.5 To avoid mismatching with ANSI/ASME B1.20.1 - 2013 threads, ISO 7-1:1994 [5] shall not be
used.
6.5 Flanges
Flanges shall comply with Annex A or with EN 1092-1:2018.
7 Design – Specific requirements
7.1 Contents gauge
7.1.1 Float gauge
7.1.1.1 The dial assembly, where applicable, shall be replaceable and the configuration for type 1 and
type 2 float gauges shall only permit the correct orientation of the dial assembly, see 7.3.3 for
interchangeability.
7.1.1.2 Stainless Steel socket head mounting screws shall be used with type 1 or type 2 float gauges
in accordance with Annex A, Figure A.1. Studs or stainless-steel socket head mounting screws shall be
used with type 3 or type 4 float gauges in accordance with Annex A, Figure A.2 (type 3) and Figure A.3
(type 4). The appropriate sealing gasket for the intended service condition shall be provided.
7.1.1.3 A hollow float or the material for a solid float shall comply with the following:
— retain buoyancy;
— withstand the normally expected variation in service conditions such as permanent immersion in
liquid/vapour LPG;
— withstand changes in relative density of the liquid; and
— fulfil the requirements of 8.14.
7.1.1.4 Means shall be provided for the float gauge mechanism to operate correctly and continuously
over the full operating range. The operating mechanism shall be such that it cannot be damaged during
the filling of the pressure vessel.
7.1.1.5 Float gauges shall be designed to allow the safe removal and replacement of the dial, when
the vessel is under pressure, without disconnecting the gauge from the pressure vessel.
7.1.1.6 The dial insert shall be assembled to ensure that the internal atmosphere is clean dry air that
does not allow moisture to condense at any temperature between –40°C and +65°C.
7.1.1.7 In case of magnetic transmission, the float magnet and the dial magnet shall be such as to
transmit reliably, in all normal operating conditions, the level of liquid during the expected life of the
gauge.
7.1.1.8 The overall accuracy of the gauge from 31 % to 69 % of the vessel volume shall be ± 5 %. The
accuracy of the gauge at ≤ 30 % and at ≥ 70 % the vessel volume shall be ± 3 % throughout all scale
readings.
7.1.2 Rotary gauge
7.1.2.1 The cross-section of the passageway through the gauge body shall at some point be limited to
1,8 mm .
7.1.2.2 The vent screw shall remain captive or be permanently attached to the body.
7.1.2.3 The direction of the venting shall be away from the operator’s expected position.
7.1.2.4 The tube shall be of sufficient rigidity not to affect the accuracy of the gauge reading and be
capable of being rotated both clockwise and anticlockwise, through 360°.
7.1.2.5 The overall accuracy of the gauge shall be within ± 2 %.
7.1.3 Fixed liquid level gauge
Fixed liquid level gauges shall meet the following requirements:
— the cross-section of the passageway through the gauge body shall at some point be limited to
1,8 mm ;
— the orifice shall be controlled by a vent screw;
— the vent screw shall remain captive, or be permanently attached to the gauge body;
— the direction of venting shall be away from the operator;
— the dip tube, where manufactured as an integral part of the gauge, shall be securely fastened;
— the length of the dip tube shall be determined in accordance with the maximum liquid filling level
depending on the grade of product and the operating conditions.
7.1.4 Slip tube gauge
7.1.4.1 The cross-section of the passageway through the gauge body shall at some point be limited to
1,8 mm .
7.1.4.2 The vent screw shall remain captive or be permanently attached to the body.
7.1.4.3 The design shall ensure that the slip tube cannot be removed from the body during normal
operation.
7.1.4.4 The slip tube shall maintain external tightness throughout its full operating range.
7.1.4.5 The overall accuracy of the gauge shall be within ± 1 % throughout all scale readings of
pressure vessel volume.
7.2 Dials for contents gauges
7.2.1 Dials for contents gauges shall be designed so that they remain transparent and the dial readings
remain legible and visible at all times throughout the service life of the gauge.
7.2.2 Dials for contents gauges shall be designed to ensure the correct fitting and orientation of the dial
to the gauge.
7.2.3 Dials shall be sealed to prevent ingress of water and internal components shall be corrosion
resistant or protected in accordance with 7.1.1.6.
7.2.4 The dial shall be designed to ensure that it reflects the position of the gauge.
7.2.5 The dial shall be manufactured from ultraviolet stabilizing material or protected so that dial
indication remains legible.
7.2.6 Where a dial is fixed using a threaded component, stainless steel shall be used.
7.2.7 Gauge marking shall read in percentage graduations. The graduations shall not be greater than
5 % and the labelling of the graduations shall not be greater than 10 % intervals. For vessels with a
diameter below 600 mm the marking may be shown as E, 1/4, 1/2, 3/4 and F with graduations every 1/8
volume.
On type 3 and type 4 gauges, gauge marking shall read in intervals of not greater than 1 % shown on the
dial.
7.2.8 For type 1 and type 2 float gauges on pressure vessels with a diameter of 600 mm and above, the
overfill gauge markings, including 85 % and above, shall be highlighted on the gauge.
7.2.9 For type 1 and type 2 float gauges on pressure vessels with a diameter of 600 mm and above, low
contents gauge readings including 20 % and below, shall also be highlighted in a distinct colour.
7.3 Telemetry
7.3.1 General
Telemetry is a technology for collecting contents gauge data/readings and transmitting the data to a
remote location by wire or wireless connection.
A telemetry system includes an electrically powered sensor, transmitter and receiver.
A telemetry system can be connected either on existing contents gauges installed on the pressure vessel,
or they can be additional to the contents gauge. When the system is additional to a contents gauge, it
requires a dial insert that can be safely interchanged with the contents gauge insert, see 7.3.3.
The telemetry system, when applied to a contents gauge, shall not interfere with its safe operation,
visibility, see 7.2.1, and functionality.
7.3.2 Specific requirements
Telemetry equipment when fitted shall not obstruct or interfere with the normal filling, operation and
maintenance of the pressure vessel.
Telemetry equipment within a hazardous area is expected to be ATEX compliant in accordance with
Directive 2014/34/EU and shall be either explosion proof or intrinsically safe and shall meet the
requirements of EN IEC 60079-0:2018 where appropriate.
Telemetry equipment shall not reduce the accuracy of the visual readings of the original dial insert/gauge
combination.
7.3.3 Interchangeability
Safe interchangeability shall meet the following requirements and as illustrated in Figure 1:
a) The dial insert bolt circle diameter shall be between 47,6 mm and 48 mm for type 1 and 58,7 mm for
type 2, including 2 threaded screws at 3,5 mm × 9,5 mm, see EN ISO 7049:2011;
b) The two threaded screws may also be trilobated screws of 3,5 mm × 10 mm, see UNI 8112 or
DIN 7500C;
c) The connecting points of a dial insert shall be distinguishable and shall accommodate orientation of
the dial insert, e.g. one lug can be rectangular in shape, while the other can be triangular in shape;
d) The dial insert diameter shall not exceed 40,6 mm for type 1 gauges and shall not exceed 51 mm for
type 2 gauges;
e) The contents gauge shall be provided with means to ensure water collection between the dial insert
and gauge does not accumulate and cause interference. This may include filling any void with suitable
material or the provision of a drain hole not less than 2,5 mm diameter;
f) The strength of the magnetic field of the dial insert in position “B” shall be a minimum of 110 G
(Gauss) and shall be sufficient to ensure engagement with its counterpart in the contents gauge. The
strength of the magnetic field of the dial insert shall not cause lift of the magnet in the contents gauge
resulting in abrasion or increased friction;
g) The strength of the magnetic field at the upper surface of the flange or head of the level gauge
(position “C”) shall be a minimum of 220 G (Gauss);
h) The depth distance (A) between the bottom of the dial insert and the upper face for the contents
gauge shall be not more than 2 mm;
i) A telemetry dial insert shall be a snug fit to any contents gauge to which it is fitted.
Key
1 Dial insert
2 Contents gauge
A Distance between bottom of the dial insert and upper face of contents gauge
B Magnet
C Magnet
Figure 1 — Interchangeability of a contents gauge
8 Design type testing
8.1 General
8.1.1 Samples, representative of the design, size and type shall be subjected to the type tests described
in Table 1. Samples of parts constructed of non-metallic materials shall be subjected to physical and
chemical tests, see 5.3.
8.1.2 Unless otherwise specified, tests shall be carried out at 20 °C ± 5 °C and ambient pressure.
8.1.3 All samples shall initially be subject to visual and dimensional inspection.
8.1.4 All pneumatic tightness and hydrostatic pressure strength tests shall be maintained for at least
2 min, unless specified otherwise in this document.
8.1.5 Test equipment connections shall be subject to dimensional inspection to ensure compatibility
with the test sample.
8.1.6 A sample design shall meet the requirements of this document only if it meets all the testing
requirements.
8.1.7 The following documents shall be available:
a) description of the sample and method of operation;
b) information on its field of application;
c) drawings consisting of the general plan, components and parts list;
d) testing procedure.
Table 1 — Design testing
Test Clause Fixed Rotary Float Slip tube
liquid gauge gauge
level
gauge
Over-torquing 8.2 X X O X
deformation
External tightness 8.3 X X X X
Internal tightness 8.4 X X N/A X
Accuracy 8.5 N/A X X X
Endurance 8.6 X X X X
Repeatability 8.7 N/A X X X
Pressure strength 8.8 X X X X
Stress cracking 8.9 X X X X
Float pressure 8.10 N/A N/A X N/A
Dimensional inspection 8.11 X X X X
Function 8.12 X X X X
Vacuum 8.13 X X X X
Float 8.14 N/A N/A X N/A
Dial insert Pressure Test 8.15 N/A N/A X N/A
X As specified in clause
N/A Not Appropriate
O If appropriate
8.2 Over-torquing deformation test
8.2.1 A sample, where connection to the pressure vessel is by means of a taper thread, shall be
subjected to an over-torquing deformation test to ensure the correct operation and tightness in that
condition. The test procedure is described below.
8.2.2 The body is fitted on a test rig representative of its intended use.
8.2.3 All stem thread types shall withstand a torque of 1,5 times the manufacturers recommended
fitting torque or the torque as shown in Table 2, whichever is the greater. Taper threaded joints shall be
assembled without sealant.
8.2.4 The sample shall then be checked for freedom of movement and correct operation prior to being
removed from the test rig. It shall then be tested for external tightness in accordance with 8.3 and internal
tightness in accordance with 8.4.
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