SIST EN 16125:2019

SLOVENSKI STANDARD
01-december-2019
Nadomešča:
SIST EN 16125:2016
Oprema in pribor za utekočinjeni naftni plin (UNP) - Cevovodi in podpore - Tekoča
in parna faza UNP
LPG Equipment and Accessories - Pipework systems and supports - LPG in liquid phase
and vapour pressure phase
Flüssiggas-Geräte und Ausrüstungsteile - Rohrleitungssysteme und -befestigungen -
Flüssigphase und ungeregelte Gasphase von Flüssiggas (LPG)
Equipements pour GPL et leurs accessoires - Systèmes de canalisations et supports -
Phase liquide et phase vapeur
Ta slovenski standard je istoveten z: EN 16125:2019
ICS:
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 16125
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2019
EUROPÄISCHE NORM
ICS 23.040.01 Supersedes EN 16125:2015
English Version
LPG Equipment and Accessories - Pipework systems and
supports - LPG in liquid phase and vapour pressure phase
Equipements pour GPL et leurs accessoires - Systèmes Flüssiggas-Geräte und Ausrüstungsteile -
de canalisations et supports - Phase liquide et phase Rohrleitungssysteme und -befestigungen -
vapeur Flüssigphase und ungeregelte Gasphase von Flüssiggas
(LPG)
This European Standard was approved by CEN on 28 July 2019.

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, Turkey 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16125:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 7
4 Design safety considerations . 10
5 Materials . 12
6 Design . 14
7 Corrosion protection and identification of above-ground pipework . 19
8 Welded pipes and fittings . 23
9 Inspection and documentation . 25
10 Testing . 26
11 Commissioning . 29
12 Maintenance . 29
Annex A (informative)  Pipe sizing – liquid phase . 30
Annex B (informative) Pipe sizing – gas phase . 36
Annex C (informative) Pipework Integrity Management Systems (PIMS) . 38
Bibliography . 40

European foreword
This document (EN 16125:2019) has been prepared by Technical Committee CEN/TC 286 “LPG
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 March 2020, and conflicting national standards shall be
withdrawn at the latest by March 2020.
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 16125:2015.
The main technical changes include:
— the removal of the environmental annex and associated clauses in favour of a reference to
CEN/TS 16765,
— the removal of Annex E (Manufacturing and type testing of composite pipes) with the intent of
developing a dedicated composite pipe manufacturing standard within CEN/TC 155. At the time of
this document going to formal vote, the proposed project within CEN/TC 155 is under consideration.
At all stages of building and operating pipework systems the use of materials and disposal of waste
material may have an effect on the environment. CEN/TS 16765 [10] sets out environmental
considerations for this document.
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, Turkey and the United
Kingdom.
Introduction
This document calls for the use of substances and procedures that may be injurious to health and/or the
environment if adequate precautions are not taken. It refers only to technical suitability and does not
absolve the user from legal obligations at any stage.
This document is intended for users who take on the responsibility for the assembly of the pipework on
site.
Protection of the environment is a key political issue in Europe and elsewhere. Protection of the
environment is taken in a very broad sense, as in the total life cycle aspects of, e.g. a product on the
environment, including expenditure of energy and during all phases from mining of raw materials,
fabrication, packaging, distribution, use, scrapping, recycling of materials, etc.
It is recommended that manufacturers develop an environmental management policy. For guidance see
the ISO 14004 [6]. It has been assumed in the drafting of this document that the execution of its provisions
is entrusted to appropriately qualified and experienced people.
All pressures are gauge unless otherwise stated.
NOTE This document uses measurement of material properties, dimensions and pressures. All such
measurements are subject to a degree of uncertainty due to tolerances in measuring equipment, etc. It could be
beneficial to refer to the leaflet “measurement uncertainty leaflet (SP INFO 2000 27 uncertainty.pdf)”[13].
1 Scope
This document specifies the requirements for the design, construction, testing, commissioning, operation
and maintenance of LPG pipework in both the liquid phase and at full vapour pressure.
This document is applicable to LPG pipework having a maximum allowable pressure of less than or equal
to 25 bar.
This document is applicable to new LPG pipework as well as to replacements of, or extensions to, existing
LPG pipework.
This document is not applicable to:
— pipelines (as defined in 2014/68/EU, PED) and their accessories;
— pipework for the propulsion systems of road vehicles or boats; and
— pipework on ships.
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, Rubber materials for seals and diaphragms for gas appliances and gas equipment
EN 751-2, 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, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases and
hot water – Part 3: Unsintered PTFE tapes
EN 837 (all parts), Pressure gauges
EN 1045, Brazing – Fluxes for brazing – Classification and technical delivery conditions
EN 1057, Copper and copper alloys – Seamless, round copper tubes for water and gas in sanitary and
heating applications
EN 1092-1, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, PN
designated – Part 1: Steel flanges
EN 1254-1, Copper and copper alloys - Plumbing fittings – Part 1: Fittings with ends for capillary soldering
or capillary brazing to copper tubes
EN 1254-2, Copper and copper alloys – Plumbing fittings – Part 2: Fittings with compression ends for use
with copper tubes
EN 1254-5, Copper and copper alloys – Plumbing fittings – Part 5: Fittings with short ends for capillary
brazing to copper tubes
EN 1515-1, Flanges and their joints – Bolting – Part 1: Selection of bolting
EN 10216-1, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 1: Non-alloy
steel tubes with specified room temperature properties
EN 10216-2, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 2: Non-alloy
and alloy steel tubes with specified elevated temperature properties
EN 10216-3, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 3: Alloy fine
grain steel tubes
EN 10216-4, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 4: Non-alloy
and alloy steel tubes with specified low temperature properties
EN 10216-5, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 5: Stainless
steel tubes
EN 10217-1, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 1: Non-alloy
steel tubes with specified room temperature properties
EN 10217-2, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 2: Electric
welded non-alloy and alloy steel tubes with specified elevated temperature properties
EN 10217-3, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 3: Alloy fine
grain steel tubes
EN 10217-4, Welded steel tubes for pressure purposes - Technical delivery conditions – Part 4: Electric
welded non-alloy steel tubes with specified low temperature properties
EN 10217-6, Welded steel tubes for pressure purposes - Technical delivery conditions – Part 6: Submerged
arc welded non-alloy steel tubes with specified low temperature properties
EN 10217-7, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 7: Stainless
steel tubes
EN 10226-1, Pipe threads where pressure tight joints are made on the threads – Part 1: Taper external
threads and parallel internal threads – Dimensions, tolerances and designation
EN 10226-2, Pipe threads where pressure tight joints are made on the threads – Part 2: Taper external
threads and taper internal threads – Dimensions, tolerances and designation
EN 10253-2, Butt-welding pipe fittings – Part 2: Non alloy and ferritic alloy steels with specific inspection
requirements
EN 12068, Cathodic protection – External organic coatings for the corrosion protection of burried or
immersed steel pipelines used in conjunction with cathodic protection – Tapes and shrinkable materials
EN 12266-1, Industrial valves – Testing of metallic valves – Part 1: Pressure tests, test procedures and
acceptance criteria – Mandatory requirements
EN 12266-2, Industrial valves – Testing of metallic valves – Part 2: Tests, test procedures and acceptance
criteria – Supplementary requirements
EN 12799, Brazing – Non-destructive examination of brazed joints
EN 13175, LPG Equipment and accessories – Specification and testing for Liquefied Petroleum Gas (LPG)
pressure vessel valves and fittings
EN 14291, Foam producing solutions for leak detection on gas installations
EN 14324, Brazing – Guidance on the application of brazed joints
EN 15001-1, Gas Infrastructure – Gas installation pipework with an operating pressure greater than 0,5 bar
for industrial installations and greater than 5 bar for industrial and non-industrial installations – Part 1:
Detailed functional requirements for design, materials, construction, inspection and testing
EN ISO 3183, Petroleum and natural gas industries – Steel pipe for pipeline transportation systems
(ISO 3183)
EN ISO 3452-1, Non-destructive testing – Penetrant testing – Part 1: General principles
EN ISO 5817, Welding – Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) – Quality levels for imperfections (ISO 5817)
EN ISO 9454-2, Soft soldering fluxes – Classification and requirements – Part 2: Performance requirements
(ISO 9454-2)
EN ISO 9606-1, Qualification testing of welders – Fusion welding – Part 1: Steels (ISO 9606-1)
EN ISO 9712, Non-destructive testing – Qualification and certification of NDT personnel (ISO 9712)
EN ISO 10380, Pipework – Corrugated metal hoses and hose assemblies (ISO 10380)
EN ISO 10497, Testing of valves – Fire type-testing requirements (ISO 10497)
EN ISO 16810, Non-destructive testing – Ultrasonic testing – General principles (ISO 16810)
EN ISO 17636-1, Non-destructive testing of welds – Radiographic testing – Part 1: X- and gamma-ray
techniques with film (ISO 17636-1)
EN ISO 17637, Non-destructive testing of welds - Visual testing of fusion-welded joints (ISO 17637)
EN ISO 17638, Non-destructive testing of welds – Magnetic particle testing (ISO 17638)
EN ISO 17640, Non-destructive testing of welds - Ultrasonic testing – Techniques, testing levels, and
assessment (ISO 17640)
EN ISO 17672, Brazing – Filler metals (ISO 17672)
EN ISO 17292, Metal ball valves for petroleum, petrochemical and allied industries (ISO 17292)
ASME B31.3, Process piping
ASME B31.4, Pipeline transportation systems for liquids and slurries
ASME B16.5, Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
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:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
accessible
capable of being reached for inspection, removal or maintenance without the removal of permanent
structures
3.2
brazed joint
joint obtained by the joining of metal parts with alloys which melt at temperatures that are generally
higher than 450 °C, but less than the melting temperatures of the joined parts
3.3
commissioning
preparation for safe service
3.4
competent person
person which by combination of appropriate qualification, training, experience, and resources, is able to
make objective judgments on the subject
3.5
composite pipe
pipe manufactured from thermoplastic and/or stainless steel which is also reinforced with stainless steel
or other non-metallic materials and has an outer thermoplastic protective cover
3.6
crimped joint
joint in which gas tightness is achieved by compression with or without a seal, but cannot be readily
disassembled and reassembled
3.7
fitting
pressure containing component fitted to an LPG pressure system
3.8
dew point
temperature below which vapour at a given pressure will condense back into liquid
3.9
flexible pipe
pipe that can be bent by hand to any radius above a set minimum without any change in performance
3.10
hydrostatic relief valve
self-closing valve which automatically, without the assistance of any energy other than that of the fluid
concerned, discharges fluid at a predetermined pressure
3.11
leak test
pressure test to determine the presence of leaks at joints or within components of a piping system
[SOURCE: ISO 14692-1:2017, 3.2.68]
3.12
Liquefied Petroleum Gas
LPG
low pressure liquefied 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
3.13
maximum allowable pressure
maximum pressure for which the equipment is designed
Note 1 to entry: All pressures are gauge pressures unless otherwise stated.
3.14
mechanical jointing
joint in which gas tightness is achieved by compression with or without a seal
Note 1 to entry: This joint can be readily disassembled and reassembled.
3.15
nominal diameter
DN
numerical designation of the size of a component, which is a convenient round number, approximately
equal to the manufacturing dimensions in millimetres (mm)
EXAMPLE DN 50.
3.16
non-return valve
valve designed to close automatically to restrict reverse flow
3.17
pipework
pressure containing enclosure used for the conveyance of LPG consisting of pipe, pipe fittings, valves and
other accessories
3.18
purging
displacing LPG with a non-flammable gas, steam or water or the reverse procedure
Note 1 to entry: Water/steam is not the preferred option for purging into service due to the difficulty of removing
water.
3.19
road tanker
rigid vehicle, semi-trailer or trailer comprising of one or more fixed pressure vessels
Note 1 to entry: Referred to as fixed tanks (tank-vehicles) and demountable tanks in the ADR.
3.20
sleeve
protective pipe through which a gas pipe passes
3.21
strength test
specific procedure intended to verify that the pipework meets the requirements for mechanical strength
3.22
threaded joint
joint in which tightness is achieved by metal to metal contact within threads with the assistance of a
sealant
3.23
void
enclosed, generally inaccessible and unventilated, space other than a service shaft
3.24
welded joint
joining of two compatible components by melting their edges and melting a suitable material into a space
between the components, or by raising the temperature of their edges to the fusion temperature and
applying pressure to join the two together
Note 1 to entry: Whilst this is most commonly applied to steel, it is also applicable to other materials such as
copper.
Note 2 to entry: Due to the application of heat, welded joints can be subject to complex stress pattern and
therefore the joints should only be made by suitably qualified personnel.
3.25
working pressure
pressure under normal operating conditions
4 Design safety considerations
4.1 General
4.1.1 The design of an LPG installation shall be done by a competent person.
4.1.2 The pipework designer shall provide information on the design and location of the pipework to
the persons responsible for the construction, installation, testing, commissioning and operation of the
pipework.
4.1.3 The pipework shall be designed, installed and constructed to allow testing and purging to be
safely carried out.
4.1.4 Pipework joints shall be kept to a minimum.
4.2 Operating conditions
Pipework used in accordance with this document shall be suitable for the following conditions:
— a minimum operating temperature of − 20 °C. In service, temperatures below this can be
encountered during short periods, for example, when filling. In some parts of Europe and certain
applications where a lower temperature than − 20 °C can be encountered, the minimum design
temperature shall be – 40 °C;
— the maximum working temperature shall be 65 °C for above ground pipework and 40 °C for
underground pipework;
— the maximum allowable pressure for pipework shall be less than or equal to 25 bar;
— pipes shall be suitable for transport and storage at − 40 °C and 65 °C.
NOTE Vacuum conditions on the pipework arising from butane at low temperature or evacuation of the
pipework can expose the pipework to a vacuum of 50 mbar absolute. The minimum pressure to which pipework is
normally exposed is 0 bar.
4.3 Protection against hazards
4.3.1 Protection against mechanical damage
Pipework shall be protected against mechanical damage. For protection of underground pipework,
see 6.6.1.5.
4.3.2 Resistance to corrosive substances and atmospheres
All pipework and fittings, including supports, shall be protected from corrosion according to the
environment and operating conditions they will be subjected to during their service life.
NOTE Stainless steel pipework and fittings can be subject to chloride induced stress cracking, e.g. coastal areas
or other areas where salt laden atmospheres can occur.
4.3.3 Protection against condensation
For vapour pressure pipework, precautions shall be taken to avoid problems occurring in the pipe and
downstream equipment due to LPG vapour condensing. Figure 1 indicates the pressure temperature
relationship for various mixtures of propane and butane.
NOTE 1 Where the stored LPG liquid temperature is higher than the temperature of the downstream pipework,
the LPG can condense to a liquid. This is known as the dew point.
NOTE 2 In Figure 1, where the LPG is exposed to a pressure above the curve, the LPG vapour will condense.
In order to prevent condensation of LPG between the pressure vessel and the first stage pressure
regulator, the pipework shall drain back to the pressure vessel. Alternatively, trace heating of the
pipework shall be considered. If this is not possible, a suitably located vapour-liquid separator (knockout
pot) may be installed in the line to allow condensation to collect and subsequently boil off without causing
problems.
Literature Reference: Buecker,D. and Wagner, W. “Reference equations of state for thermodynamic properties of
fluid phase n-Butane and Isobutane” J. Phys. Chem. Ref. Data, 35(2):929-1019, 2006
Key
X Temperature in °C
Y Pressure in bar
100 % Propane
80 % Propane 20 % Butane
50 % Propane 50 % Butane
20 % Propane 80 % Butane
100 % Butane
Figure 1 — Dew point graph
5 Materials
5.1 General
5.1.1 All materials in contact with LPG shall be physically and chemically compatible with LPG under
all operating conditions for which the pipework is designed.
5.1.2 Materials for pipework shall be selected to give adequate strength in service. Consideration shall
also be given to other modes of failure such as atmospheric corrosion, brass dezincification, stress
corrosion, impact or material failure.
Electrolytic corrosion of dissimilar metals at joints shall be prevented by the selection of compatible
materials.
Materials and components shall comply with one or more of the standards listed in Table 3, Table 4,
Table 5 and Table 6.
Materials and components can be reused where they comply with the following requirements:
— are suitable for the proposed service in light of the history of the material or component, and;
— are inspected since the previous use to reveal any defect that could impair safety, strength or
pressure tightness.
Flexible hoses shall be in accordance with EN ISO 10380 (for corrugated metal hoses) and EN 1762 (for
rubber hoses).
5.2 Accessories
5.2.1 General
Accessories shall be capable of withstanding the service conditions for which the system is designed.
5.2.2 Gaskets and ring joints
Gasket and ring joint materials shall be compatible with LPG over the range of operating conditions;
see EN 549.
5.2.3 Valves and fittings
5.2.3.1 Ball valves, globe valves, and non-return valves shall be pressure tested to the relevant
requirements of EN 12266-1 and EN 12266-2 or EN 13175, where appropriate.
5.2.2.2 All isolation valves (except those for instrumentation) shall have the means for indicating the
settings of the valve e.g. closed, open.
5.2.3.3 Shut-off valves greater than DN 25, excluding pressure vessel valves, in liquid service pipework
should preferably be ball valves in accordance with EN ISO 17292 and fire safe in accordance with
EN ISO 10497.
5.2.3.4 Except where proprietary components are being installed, all liquid connections larger than
DN 50 and vapour connections larger than shall DN 80 shall be flanged. For road tankers, connections up
to DN 80 may be threaded.
5.2.3.5 Compression fittings shall suit the material, size of the pipe and the maximum working
pressure of the system.
5.2.3.6 Bolts, screws, studs and nuts for flanges shall be correctly sized and compatible with the
material and class of the flange design, e.g. see EN 1092-1.
5.3 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 valves and fittings. Sealants shall comply with EN 751-1, EN 751-2
or EN 751-3.
6 Design
6.1 General
6.1.1 For guidance on pipe sizing for liquid pipework see Annex A.
6.1.2 For guidance on pipe sizing for vapour pipework see Annex B.
6.1.3 Where stored and handled as individual grades or products (e.g. propane, butane), storage and
handling systems shall be totally segregated or physically separated using valve interlocks, etc. Where
product mixes are handled, components shall be designed for the most onerous case e.g. propane design
pressure and minimum design temperature, relief system capacity, ability to withstand vacuum
conditions, etc.
6.2 LPG pipework installation technical documentation
The designer shall ensure that technical documentation contains the following information (with parts
lists where appropriate):
a) the location and design of supports;
b) the location and design of wall and floor transits, points where pipework crosses or runs parallel
with other systems, etc.;
c) the location of pumps, compressors, meters and other equipment, stating the make, type and
connection sizes;
d) types of joints, gaskets, bolts, etc.;
e) the pipe diameters, maximum allowable pressure, design pressure, materials and types of coatings;
f) the location and sizes of valved points for testing and purging;
g) maximum flow; and
h) cathodic protection system, where fitted.
6.3 Measuring instruments
LPG installations shall incorporate such measuring instruments and test points as are necessary for their
safe operation.
6.4 Over Pressure protection
6.4.1 For sections of pipework where liquid can be trapped in between isolation valves, suitable
pressure relief protection shall be provided (e.g. by a hydrostatic relief valve discharging to a safe
location).
6.4.2 Where hydrostatic relief valves are used, they shall be set to discharge above the maximum
working pressure of the system but not greater than the maximum allowable pressure of the pipework.
6.4.3 The positioning and/or discharge point of hydrostatic relief valves shall be located so as not to
impinge on personnel, pressure vessels or equipment in the event of a release.
6.4.4 To reduce the risk of blockage, hydrostatic relief valve inlet connections shall not be installed in
the bottom quarter of horizontal pipe.
6.4.5 Hydrostatic relief valves shall have caps fitted to prevent the entry of debris and water without
affecting the operation of the valve.
6.4.6 When hydrostatic relief valves are installed in enclosed spaces, especially where personnel are
present, suitably sized discharge pipework, which will not restrict the capacity of the hydrostatic relief
valve, shall be fitted and piped to the outside, discharging at high level or, where practical, piped back to
the storage pressure vessel. A sign shall be fitted adjacent to the discharge pipework outlet. Where the
discharge is not to atmosphere, the effect of the backpressure on the outlet setting of the hydrostatic relief
valve shall be considered.
Hydrostatic relief valve piping connections shall not impose strain on the relief valve.
Where self-closing isolating devices are used for hydrostatic relief valve connections to pipework, they
shall only close when the hydrostatic relief valve is removed from the device.
6.5 Above-ground pipework
6.5.1 General
The following provisions for spacing are recommended.
6.5.2 Clearance above ground
6.5.2.1 Pipework shall not be laid directly on the ground.
6.5.2.2 Pipework shall have at least a 50 mm clearance from the finished ground level.
6.5.2.3 Pipework shall be suitably located so as not to cause a trip hazard.
6.5.2.4 Pipework shall be suitably protected from vehicular and other mechanical damage.
6.5.2.5 Pipework shall be designed to allow for easy access for inspection and maintenance.
6.5.3 Pipework separation distances from above-ground electrical services
The separation distance shall be at least 250 mm between any pipework and any above-ground:
— metal electrical conduit;
— electrical wire or cable; or
— electrical earthing electrode.
NOTE This requirement does not apply to equipotential bonding of the pipework or heat tracing of the
pipework.
6.5.4 Ventilation of concealed piping
6.5.4.1 Pipes through ducts or sleeves
Ducts or sleeves shall be ventilated at either one or both ends. Where ventilation is at one end only, it
shall be the lowest end of a non-horizontal duct or sleeve.
Ventilation openings shall terminate in a safe location.
All openings shall be the full cross-sectional area of the duct or sleeve less the cross sectional area of the
pipe.
No other pipes or cables shall run through ducts or sleeves containing LPG pipes.
6.5.4.2 Pipes through walls
All pipes that pass through walls shall be ducted or sleeved, with the duct or sleeve in compliance with
6.5.4.1.
6.5.4.3 Pipes through voids
Pipes shall not be installed directly in an unventilated void unless one of the following options is used:
— the pipes shall be sleeved continuously through the unventilated void, with the sleeve ventilated at
one or both ends into a safe place; or
— the unventilated void shall be filled with a crushed inert infill to reduce to a minimum the volume of
any gas which may accumulate. The infill material should be of a dry, chemically neutral and fire
resistant nature, e.g. crushed slate chippings or dry washed sand.
6.5.5 Pipe supports
6.5.5.1 Pipe supports shall be capable of supporting the pipework and its contents.
6.5.5.2 Pipe supports shall not interfere with the integrity of the supporting structure.
6.5.5.3 The spacing of pipe supports shall be suitable for the material type, diameter, weight and
thickness. Table 1 provides indicative spacing for pipework. Pipe support spacing's for flexible pipes shall
be obtained from the manufacturer.
6.5.5.4 Pipe supports shall be capable of maintaining the pipework in the intended position and
controlling movement of the piping system.
6.5.5.5 Pipe support material shall be compatible with the pipework material or insulated from the
pipework to prevent electrolytic corrosion.
6.5.5.6 Vibration, surge pressures and valve operating torque shall be considered in the design of
pipework and supports incorporating mechanical equipment such as pumps and valves.
Table 1 — Spacing of pipe supports for rigid pipework
Nominal diameter (DN) Support spacing
(mm) (m)
Steel pipe Copper pipe Stainless steel
8 2 1 1
10 2 1,5 1,5
15 2 1,5 1,5
18 - 1,5 1,5
20 2,5 1,5 1,5
25 2,5 2 2
32 3 2,5 2,5
40 3 2,5 2,5
50 3 3 3
65 3 3 3
80 4 4 4
100 5 4 4
125 7 4 4
150 8 4 4
200 9 4 4
6.6 Underground pipes
6.6.1 General
6.6.1.1 Whenever there are no specific provisions in national regulations, the following provisions
for spacing are recommended.
6.6.1.2 Pipes shall be located at least 1 m away from the outside of any building except at the point
of entry or where there are alternative national requirements.
6.6.1.3 Pipe routes shall be chosen to minimize the length of pipe required.
6.6.1.4 Buried metallic pipes shall have active or passive means of protection (e.g. cathodic
protection, protective coating or wrapping, etc.) or shall be inside a buried outer pipe or conduit which
terminates above ground level or in a suitable inspection pit. Provision shall be made to facilitate periodic
leak testing.
6.6.1.5 Underground pipes shall have a depth of cover of at least 600 mm or be protected in such a
way as to protect the pipe from physical damage.
6.6.1.6 To avoid undue stress, buried pipework shall be bedded on a firm compacted surface along
its entire length.
NOTE To accomplish this, it is possible to trim the trench base to ‘let in’ the fittings, collars or flanges to ensure
the whole length of pipe is evenly supported.
6.6.1.7 The bedding material should not be of the type that can be washed away by the action of
water unless the trench is lined with a suitable membrane which will allow any water to drain but not
allow the passage of the backfill material.
6.6.1.8 Bedding material and backfill shall be of a type which will not have an adverse effect on the
pipe or pipe coating. The bedding material, within 75 mm of the pipe, shall be free of stones or other
materials, which could damage the pipe or pipe coating or as required by the pipe manufacturer.
6.6.1.9 Identification warning tape shall be placed at least 150 mm above the top of the pipe.
6.6.1.10 Bedding material, backfill material and installation procedures for pipework using composite
pipes, shall comply with the pipe manufacturer's instructions.
6.6.2 Underground pipe separation distances
6.6.2.1 The separation distances horizontal and/or vertical in Table 2 shall be applied for
underground LPG pipes and underground services.
6.6.2.2 Any underground pipes crossing any other service shall cross at an angle of not less than 45°.
Table 2 — Separation distances for underground pipes
Service type Separation distance –
(mm)
a
non-ducted electrical supply cable less than 1 000 V AC 300
electrical earthing electrode 500
communications cable 300
pipework carrying oxygen 500
pipework carrying toxic or corrosive substances 1 500
pipework carrying steam or hot water above ambient 300
temperature
any other service pipework 300
a
For electrical supply cables greater than 1 000 V AC specialist advice should be sought.
6.7 Pipework loading
6.7.1 All pipework shall have sufficient flexibility to prevent:
— excessive stress in the piping material and attached equipment caused by thermal expansion and
contraction;
— excessive bending or loading at joints; and
— movements at points of connection to equipment, at anchorage points or guide points.
NOTE This can be achieved by the use of bends, loops, etc. formed in the piping system.
6.7.2 Where flexible connections are used to allow for unavoidable pipework movement, vibration or
misalignment, their lengths should be as short as reasonably practicable and, where applicable, maintain
electrical continuity. Their orientation and length should ensure the movement does not put them into
tension or impose torsional stresses
6.8 Equipotential bonding
6.8.1 External pipework carrying liquid or vapour should have electrical continuity with the storage
vessel(s), except where cathodic protection (CP) is fitted as a precaution against static electricity. The use
of bonding straps is not normally required for flanged pipework.
6.8.2 Where underground or mounded pressure vessels are equipped with a cathodic protection
system, the cathodic protection system shall be electrically isolated from the pipework.
6.8.3 The design of equipotential bonding of pipework and other equipment shall be carried out by
competent persons.
7 Corrosion protection and identification of above-ground pipework
7.1 Corrosion protection
7.1.1 Pipework shall be protected so as to prevent external corrosion, arising from atmospheric
exposure, by the application of a protective coating system.
7.1.2 The protection system applied shall take into account:
— the local operating environment;
— the periods between periodic inspections/maintenance; and
— any external fire protection coatings or other coating.
7.1.3 Protection shall be applied in accordance with the coating manufacturer's instructions.
7.1.4 Details of the actual system used, the expected life and coating maintenance recommendations
shall be included in the operating instructions.
7.2 Colour coding
7.2.1 LPG pipework shall be clearly identified or colour coded.
7.2.2 Flow direction shall be marked where necessary.
7.3 Reflectivity
Where thermal gain from direct sunlight may cause an issue with liquid, pipework shall have a highly
reflective colour.
Table 3 — Criteria for steel pipe (operating limit ≤ 25 bar)
Acceptable pipe Acceptable fittings Acceptable welded
joints
Pipe Limiting Fitting Limiting conditions Method Limiting
conditions conditions
EN 10216-1, External Screwed Shall not to be used Fillet weld Where
EN 10216-2, corrosion flange, carbon for joining pipe in welding is
EN 10216-3 and protection steel in lengths unless other accordanc being
EN 10216-4 and required. accordance joining methods are e with carried out,
EN 10217-1, Not with impracticable. EN 15001- the welder
EN 10217-2, permitted EN 1092-1. Flanges forming a 1. shall be
EN 10217-3, for Taper joint shall be of the approved in
EN 10217-4 and undergroun external and same size and face accordance
EN 10217-6 as d service taper internal type. with
appropriate. unless threads in External corrosion EN ISO 960
EN ISO 3183 wrapped accordance protection required. 6-1.
ASME B31.3 with a with Only above ground. External
ASME B31.4 protective EN 10226-1 Not suitable for use corrosion
covering, or EN 10226- with schedule 40 protection
painted or 2. pipe. required.
sheathed or, Steel butt- External corrosion Butt weld
where welded pipe protection required. in
buried, can
fittings shall accordanc
be fitted
be in e with
with
accordance EN 15001-
cathodic
with 1.
protection
EN 10253-2.
in
Socket- External corrosion Fillet weld
accordance
welded protection required. in
with
fittings such accordanc
EN 12007-1
as tee, bend, e with
and reducer and EN 15001-
EN 12007-3.
cap shall be 1.
Not
welded in
permitted
accordance
for
with
undergroun
EN 10253-2.
d service
Welded flange Shall not to be used Slip-on
beneath a
carbon steel for joining pipe type
building.
or steel alloy lengths unless other flanges and
shall be in joining methods are other type
accordance impracticable. flanges
with Flanges forming a shall be
EN 1092-1 joint shall be of the fillet
and EN 1515- same size and face welded in
1. type. accordanc
External corrosion e with
protection required. EN 15001-
1.
Table 4 — Criteria for stainless steel pipe (operating limit ≤ 25 bar)
Acceptable pipe Acceptable fittings Acceptable welded joints
Pipe Limiting Fitting Limiting Method Limiting
conditions conditions conditions
Stainless Shall not be Suitable  Butt weld in Where
Steel permitted welded accordance welding is
Welded pipe for fittings with being carried
in undergrou should be EN 15001-1. out, the
accordance nd service used in welder shall
with beneath a accordance be approved
EN 10216-5. building. with in accordance
Seamless Not EN 10253-2. with
pipe in permitted EN ISO 9606-
Welded Shall not be
accordance for 1.
flange in used for
with undergrou
accordance joining pipe
EN 10217-7. nd service
with lengths
unless
EN 1092-1. unless other
provided
joining
with methods are
protective impracticable.
covering in Flanges
accordance forming a
with
joint shall be
EN 12068.
of the same
size and face
type
Composite Shall not be Components  Mechanical Joints shall be
stainless permitted that jointing using accessible for
steel flexible for use as a terminate components inspection
(Grade final with a NPT specified or and
EN 1.4404) connection thread, provided by maintenance.
pipe with or to an welding end the pipe Jointing shall
without appliance. and flanges in manufacturer be carried out
permeation accordance . by persons
barrier filler with certified by
coating and EN 1092-1 or the
with ASME B16.5. manufacturer
external PE- Component .
LD jacket. specified or
provided by
the pipe
manufacturer
.
Table 5 — Criteria for copper tube (operating limit ≤ 25 bar)
Acceptable pipe Acceptable fittings Acceptable welded joints
Pipe Limiting Fitting Limiting Method Limiting
conditions conditions conditions
Copper tube DN 6 Shall not be Copper alloy Not Compression Not permitted
−32 (outside permitted compression permitted in underground
diameter) in for fittings in ground
...