Version 1.0  May 21, 2024

Transportable CNG Cylinder Service Manual

p/n TC_ 500_1-A

p/n TC_ 500_3-A

p/n TC_ 500_5-A

Copyright © 2024 Hexagon Agility

All rights reserved.

All specifications are subject to change without notice.

All commercial symbols, trademarks, and trade names are protected trademarks of their respective holders.

The information provided within this document is proprietary and confidential. All prior versions, including updates and revisions forwarded separately, are proprietary. The information provided by Hexagon Agility to its customers and clients is solely for the use of those customers and clients. No portion of this publication may be reproduced or distributed without express written consent of Hexagon Agility. Hexagon Agility reserves the right to utilize the intellectual property contained within this publication as content for any other publication produced by Hexagon Agility.

HEXAGON®, AGILITY® and X-STORE® are registered in U.S. Patent and Trademark Office.

Contact Information

Hexagon Agility GmbH

Otto-Hahn-Straße 5

34123 Kassel


Phone: +49 (0)561 58549-0

FAX:     +49 (0)561 5854927-29

Table of Contents

Contact Information                                                                                                

1.... About this Manual                                                                                         

1.1       Applications                                                                                        

1.2       Liability

1.3       Warranty

1.4       Pictures and Illustrations

1.5       Symbols and Definitions

1.6       Abbreviations

2.... Safety                                                                                                             

2.1       Safety Instructions and Measures

2.2       Intended Use

2.3       Foreseeable Misuse

2.4       Limitation of Use

2.5       Further Regulations

2.6       Cylinder Labels

2.7       Safety Hazards and Prevention

2.8       Owner Obligations and Personnel Qualifications

2.8.1...... Owner Obligations

2.8.2...... Personnel Qualifications

2.9       Safety Equipment

2.10     Gas Requirements

                2.10.1.... Operating Gas – Compressed Natural Gas (CNG)

                2.10.2.... Purging Gas – Nitrogen (N2)

2.11     Filling/Unloading Station Requirements

2.11.1.... Filling and Unloading Requirements

2.11.2.... Gas Connection

2.11.3.... Ventilation Requirements for Enclosed Working Spaces

2.12     Tools and Consumables for Operation and Routine Maintenance

2.13     Required Actions After a Traffic Accident or Thermal Event

2.13.1.... Traffic Accident

2.13.2.... Thermal Event

2.14     Relevant Standards

3.... Description

3.1       Cylinder Function

3.2       Cylinder and Component Composition

4.... Transport, Handling, and Storage

4.1       Cylinder Transport

4.2       Cylinder Handling

4.3       Cylinder Storage

5.... Filling, Mounting, and Installation Procedures

5.1       Initial Filling Procedure

                5.1.1...... Cold Fill Procedure

5.2       Valve Installation

                5.2.1...... Installing Valves

5.3       Cylinder Installation Instructions

5.3.1...... Neck Mounting

5.3.2...... Vertical Mounting

5.3.3...... Valve Adapter

5.3.4...... Valve Adapter Sealing Wax

6.... Operating Conditions

7.... Maintenance

7.1       Safety

7.1.1...... Personnel Qualification

7.1.2...... Periodic Inspections

7.2       Cleaning

7.3       Cylinder Inspection

7.3.1...... Cylinder Inspection Procedure

7.3.2...... Cut/Scratch Damage

7.3.3...... Superficial Cracks

7.3.4...... Abrasion Marks and Scratches

7.3.5...... Chemical Damage

7.3.6...... Impact Damage

7.3.7...... Loose Fiber Ends

7.3.8...... Leak Test

7.4       Cylinder Inspection Checklist

8.... Technical Data

8.1       Operating Parameters

8.2       Arid “Dry” Gas Requirements

8.3       Humid “Wet” Gas Requirements

9.... Decommissioning and Disposal

9.1       Venting Residual Gas from a Cylinder

9.2       Remove Cylinder Valve, Valve Adaptor, Plug

9.3       Disable Cylinder

9.4       Repurpose or Recycle Cylinder

1. About this Manual

This Operation Manual contains user information for the intended and safe use and routine maintenance of Hexagon Agility X-STORE compressed natural gas (CNG) cylinders used in XSTORE Multiple Element Gas Container (MECG) modules. This Manual and the complementary documents (“they”) are part of the XSTORE module documentation.

The following aspects regarding this Manual and the complementary documents must be followed:

1. Read the Manual carefully before use, in particular the safety instructions. 

2. They must be accessible at all times to the operating and maintenance personnel.

3. They must always be kept in the vicinity of the XSTORE module during its entire service life.

4. If the XSTORE cylinder or X-STORE module is passed on to other Owners, they must also be passed on and supplemented with Owner-specific content (e.g., checklists, protocols).

5. Update the Manual whenever a supplement from the manufacturer is provided.

The information in this Manual is binding. Every user of the XSTORE cylinder must have fully read and understood this Manual prior to use. The instructions, prohibitions and commands of this Manual must always be followed and all safety notices must be observed.

1.1 Applications

This service manual applies to the following pressure cylinder part numbers (p/ns) used for non-automotive uses such as transport and distribution per ADR/TPED:

Cylinder Type

Part Number





1.2 Liability

The user is liable for any failure to follow this Manual. Any warranty is declared null and void for any damage to the XSTORE cylinder or accessories or operational malfunctions which are a result of failure to follow this Manual or due to incorrect use by the user.

Unauthorized conversions or modifications to the XSTORE cylinder or accessory parts which occur without the prior consent of the Hexagon Agility are prohibited and thus excluded from the liability.

1.3 Warranty

The legally prescribed warranty obligation applies. Further warranty obligations apply only if contractually agreed. Damage due to wear caused by use of the XSTORE cylinder is excluded from the warranty.

Hexagon Agility will not assume any responsibility, and warranty and will be discharged from any claims towards third parties if personal injury and material damage can be traced back to one or more of the following causes by the Owner or a third party. These include the following:

1. inappropriate use of the XSTORE cylinder

2. failure to follow the instructions in this Manual

3. failure to adhere to the specified limits of use and operating conditions

4. inappropriate commissioning, operation, inspection, or maintenance of the X‑STORE cylinder

5. failure to adhere to the prescribed inspection and maintenance intervals

6. modifications to the XSTORE cylinder or to individual components which were not expressly authorized by Hexagon Agility

7. use of accessories or replacement parts which are not approved by Hexagon Agility

1.4 Pictures and Illustrations

The pictures and illustrations in this Operation Manual should be regarded as examples, sketches, and/or schematic diagrams and are intended solely as a visual aid for the relevant facts and circumstances.

The pictures and illustrations do not necessarily correspond to the scope of supply. Deliveries cannot be inferred from the pictures and illustrations. Depicted components, auxiliaries, tools, etc. are only provided insofar as contractually agreed upon.

Illustrations are not necessarily true to scale. Depicted dimensions, arrangements, and proportions can differ from the scope of supply.

1.5 Symbols and Definitions

The following warning symbols and definitions are used in this Operation Manual:

Table 1–1: Warning Symbols and Flags per European Machinery Directive

Flag or




Imminently hazardous situation that, if the safety measures are ignored, could result in death or serious injury.


Possibly hazardous situation that, if the safety measures are ignored, could result in death or serious injury.


Possibly hazardous situation that, if the safety measures are ignored, could result in minor injuries.


Possibly hazardous situation that, if the safety measures are ignored, could result in material damage.

1.6 Abbreviations

This Operation Manual uses the following specific abbreviations:

Table 1–2: Abbreviations Used




equipment designed to be used in explosive atmospheres

(Appareils destinés à être utilisés en atmosphères explosives)


Anerkanntes Technisches Regelwerk

recognized technical codes for transport at sea and on waterways (Germany)


compressed natural gas

dB (A)

decibel, A-weighted scale


German Institute for Standardization

(Deutsches Institut für Normung)


European Standard

(Europäische Norm)


gas system inspection



International Organization for Standardization


original equipment manufacturer


personal protective equipment


parts per million


temperature-activated pressure relief device



2. Safety

The following requirements must be fulfilled to ensure that all facilities and personnel necessary for the use of the XSTORE cylinder are properly prepared and in proper condition for the safe and efficient use of the cylinder.

2.1 Safety Instructions and Measures

Read all safety notices thoroughly prior to using the XSTORE cylinder and observe all notices when using the cylinders.

Safety notices draw attention to the dangers of possible personal injury, material damage, and environmental damage. Safety notices also contain information on the prevention and avoidance of risk.

2.2 Intended Use

X-STORE cylinders are pressure vessels typically used in a XSTORE module multiple element gas container (MEGC) which is designed for the transport, storage, and dispensing of compressed natural gas (CNG).

The XSTORE cylinder must only be used under compliance with the operating conditions and requirements specified in this Manual and (if applicable) the X-STORE Module Operation Manual.

The XSTORE cylinder is intended to be operated only by trained/certified users.

The XSTORE cylinder has been technically designed and must be deployed and used for this purpose only. Every other, additional, or exceeding use of the XSTORE cylinder or its accessories is considered as misuse.

Hexagon Agility cannot be held liable for any personal injury or material damage caused by misuse of the cylinder or its accessories.

2.3 Foreseeable Misuse

A foreseeable misuse of the XSTORE cylinder is the use for any purpose not mentioned above in 2.2 "Intended Use" and/or any noncompliance with the operating conditions specified in this Manual.

Foreseeable misuses include but are not limited to:

1. Any use other than the above mentioned.

2. Use of incorrect equipment that does not comply with the intended use.

3. Manipulation of the system by means such as bypassing safety mechanisms, etc.

4. Extensions or modifications carried out by the Owner or Operator on their own initiative, which are neither covered by the applicable approval specifications nor authorized by the manufacturer.

5. Filling the cylinder with other gases than specified.

6. Purging the cylinder with other gases than specified.

7. Connecting the cylinder to filling stations that do not meet the specified requirements.

8. Installing the cylinder in a manner which does not meet the specified requirements.

2.4 Limitation of Use

1. X-STORE modules and X-STORE cylinders must not be operated in explosion-prone atmospheres of Zones 0, 1, 2, 20, 21, 22 as defined by the Atmospheres Explosibles Directives (“ATEX”)*, or in underground mining areas as it is not designed for that purpose.

2. X-STORE modules and X-STORE cylinders must not be operated when severe weather is imminent, including but not limited to during or immediately after thunderstorms, lighting storms, or under other hazardous conditions.

*Directive 99/92/EC also known as 'ATEX 137' or the 'ATEX Workplace Directive'; Directive 2014/34/EU also known as 'ATEX 114' or 'the ATEX Equipment Directive.'

2.5 Further Regulations

The legal regulations and the in-company regulations of the Owner must be observed in addition to the information in this Manual.

The Owner is considered the person or entity that operates the X‑STORE cylinder or allows other qualified and instructed personnel to undertake operation.

All personnel authorized by the Owner to carry out work on or with the X‑STORE cylinder must provide valid written proof of training and/or certification required by legal and in-company regulations.

Regulations which must be observed include—but are not limited to—the following:

1. handling of hazardous substances

2. handling of flammable gases

3. explosive atmospheres

4. provision and wearing of personal protective equipment (PPE)

5. fire protection and firefighting

6. Regulations on special certification programs according to the nature of tasks to be performed, e.g.: In Germany, all personnel who inspect, repair, or maintain similar equipment must have a Gasanlagenprüfung (GAP) certification.

2.6 Cylinder Labels

X-STORE cylinders may be identified by labels containing specifications and approvals.

X-STORE cylinder label descriptions (ISO 11119-3 / EN 12245 / ADR)





Cylinder Thread

specifies the bottle thread (cylinder thread) used



cylinder constructor


Serial Number

unique cylinder identification number


Working Pressure

cylinder pressure operating range


Test Pressure

internal pressure applied to the cylinder during hydrostatic testing


Empty Weight

cylinder mass in kg



cylinder capacity in liters


Used Norm (Applied Standard)

official norm under which the cylinders are certified


Inspection Body

number of the admission authority


Country of Approval



Date of Initial Inspection

date on which the cylinder has been first tested


First Periodic Inspection

date for the first periodic inspection


Minimum Pressure

minimum pressure of the cylinder  NOTICE  Do not apply vacuum to the cylinder.


Notified Body

marking of the notified body


Life Time

NLL (Non Limited Lifetime)


Working Temperature

cylinder temperature operating range


Maximum Torque

apply no more than the stated torque

2.7 Safety Hazards and Prevention

During operation X-STORE cylinders contain flammable content under high pressure. Although the design is safe, tested, and certified, there are some potential safety risks which must be understood and prevented.

Servicing or repairing cylinders without adhering to proper training, instructions, procedures, and without using proper tools and equipment may result in severe injury or death to yourself and others and may damage the cylinder and surroundings.

Always use the proper tools and safety equipment, observe a safe working perimeter, and follow all specific and general prohibitions, instructions, and procedures correctly without skipping steps.

2.7.1    Compressed Natural Gas (CNG) Hazards and Prevention

Be aware of the possible dangers of working with CNG as a flammable gas under high pressure. CNG also presents an asphyxiation danger if permitted to accumulate.

 WARNING  Risk of serious injury or death by explosion.

CNG is a flammable gas which is lighter than air. CNG can form an explosive mixture in combination with air. Any ignition source—flame, spark, electrostatic discharge, extreme heat—can cause explosion, even if only residual CNG is present.

 WARNING  Risk of serious injury or death by fire.

CNG is a flammable gas that burns with a visible flame. Any ignition source flame, spark, electrostatic discharge, extreme heat—can cause ignition and/or explosion, even if only residual CNG is present.

 WARNING  Risk of serious injury or death by asphyxiation.

In the case of a concentration of CNG and high level exposure, inhalation can cause serious injury or death. Symptoms can include loss of mobility and loss of consciousness. The victim may not notice the suffocation.

In case of an accident in which the victim is not breathing, remove victim to fresh air—ideally using a self-contained breathing apparatus, provide artificial respiration, keep victim warm and calm, and call an emergency doctor.

 WARNING  Risk of insufficient ventilation.

► Ensure ventilation openings are always clear and not blocked.

Always observe the following measures to minimize the inherent properties of CNG:

► Do not place the X-STORE cylinder near any ignition sources (exhaust pipes, electric motor, electrical mains, etc.).

► Do not use ignition sources (fire, open flame, or any equipment that could be a possible source of ignition) in the surroundings of the X-STORE cylinder.

► Do not smoke or vape in the surroundings of the X-STORE cylinder.

► If applicable: Do not use or work on the X‑STORE cylinder without a grounding system properly connected to a safe grounding connection.

► Any work should preferably be done outdoors.

► Ensure a good ventilation rate if use in an enclosed working space is imperative (see 2.3.5 "Ventilation Requirements for Enclosed Working Spaces.")

► Venting must be performed outdoors only.

► Perform Leak Checks when directed and a quarterly comprehensive Leak Check of the entire X-STORE module.

► Always use nitrogen to clean or purge X-STORE cylinder contents; never use compressed air.

2.7.2    Pressure Vessel Hazards and Prevention

X-STORE cylinder gas pressure may exceed 250 bar (3625 psi) under certain conditions; always assume components and plumbing are under pressure before performing any task.

 WARNING  Risk of serious injury from high system pressure resulting in uncontrolled movements of loosened parts.

► Improperly loosened parts of pressurized systems can become projectiles and cause serious injury.

Observe the following measures to minimize risk when working on pressure vessels like the X-STORE cylinder:

► Never attempt to cut plumbing while system is under pressure.

► Never remove or relieve any pipe fitting, valve, or any other component while the system is under pressure.

► Always depressurize or vent cylinder prior to working on cylinder plumbing and hardware.

► Always defuel the X-STORE cylinder prior to servicing cylinder valves, T-PRDs, or associated fittings.

 CAUTION  During cylinder venting sound level can exceed 110 dB (A).

► Wear hearing protection while venting cylinder.

2.7.3    Temperature Extreme Hazards and Prevention

 CAUTION  Cylinder surface may become cold during operation.

► Wear protective gloves.

Cylinder proper operation and maximum uptime is conditional upon continuous monitoring of temperature extremes.

 NOTICE  Risk of damage due to failure to monitor gas temperature.

Gas temperature readings must always be available and observed during any operation of the X-STORE cylinder. Exceeding the limits of the allowable gas temperature range may cause serious material damage and is not allowed.

► Perform filling or defueling/unloading procedures only within prescribed temperature ranges.

2.8 Owner Obligations and Personnel Qualifications

An “Owner” is a person or entity that authorizes Personnel (as defined below) to carry out work on, transport, inspect, service, repair, or any activity related to, or surrounding the X-STORE cylinder (collectively called “Operating” or “Operation”).

“Personnel” is any person or entity that is authorized by an Owner to Operate the X-STORE cylinder including but not limited to filling station personnel, transport drivers, and end-customer (where gas will be delivered) personnel.

2.8.1    Owner Obligations

An Owner must:

1. Define, provide, and enforce all guidelines following from the Operation Manual and from the legal and in-company regulations in the form of work instructions and instructions on accident prevention, occupational safety and health, and fire prevention and firefighting;

2. Regularly check this Operation Manual for compliance with current regulations as applicable;

3. Ensure Personnel meet qualifications listed below prior to Operating a cylinder;

4. Unambiguously define the areas of responsibility for proper execution of all cylinder Operations;

5. Ensure that unauthorized persons are denied access to the cylinder;

6. Ensure that the cylinder is used only as intended and within the operational limits;

7. Provide and keep personal protective equipment (PPE) and safety equipment in good condition for Personnel use when Operating cylinders (see 2.9 "Safety Equipment"); and

8. Keep adequate records of Personnel proof of training and/or certification required by legal and in-company regulations.

2.8.2    Personnel Qualifications

Personnel must meet the following requirements prior to and during Operating of a cylinder.

All personnel must:

1. Read and understood this cylinder operation manual in its entirety;

2. Be at least 18 years of age;

3. Be in reasonably good health, and have appropriate levels of physical and mental wellness;

4. They are rested, focused, and not under the influence of drugs, alcohol, or medication, which could limit ability to react and receptiveness.

5. Be cautious of dangers and follow safety notices;

6. Follow applicable work instructions, instructions on accident prevention, occupational safety and health, and fire prevention and firefighting;

7. They always pay attention to cleanliness and order in the workplace.

8. They wear all necessary personal protective equipment (PPE) to ensure work safety (see 2.9 "Safety Equipment.")

9. They are instructed in and are able to perform first aid, and

10. Provide to Owner written proof of training and/or certification required by legal and in-company regulations.

Further, unless prescribed otherwise, Personnel must also meet the minimum qualifications listed in Table 2–1 to carry out respective tasks:

Table 2–1: Personnel Qualifications



assembly / installation

trained and instructed by Hexagon Agility


trained and instructed by Owner

routine inspection and maintenance; cleaning

trained and instructed by Owner

periodic inspection

trained and instructed by Hexagon Agility

advanced maintenance, service, repair(1)

trained and instructed by Hexagon Agility


trained and instructed by Owner

disassembly / disposal

trained and instructed by Owner

2.9 Safety Equipment

Unless prescribed otherwise, the following personal protective equipment (PPE) is mandatory.

Table 2–2: Personal Protective Equipment (PPE) per Person







safety gloves (thermal protective gloves)




safety shoes




safety visor or safety goggles




hearing protection

venting operation



reflective vest or jacket


 WARNING  Personal protective equipment (PPE) must meet legal requirements and in-company regulations.

►  Always check the PPE condition before use.

In addition to personal protective equipment (PPE), at least the following safety equipment must be available at every work space.

Table 2–3: Minimum Safety Equipment Required per Working Space






fire extinguisher



first aid kit



flammable gases concentration measuring device

WARNING  Safety equipment must meet the requirements of legal and in-company regulations.

►  Always check the condition of the safety equipment before use.

2.10 Gas Requirements

The X‑STORE CNG cylinder was designed and certified to carry compressed natural gas and biogas also known as renewable natural gas (RNG) only.

►  Do not use X‑STORE CNG cylinders to transport or store any other gas.

►  Only nitrogen (N2) gas is permitted for purging.

►  Filling the cylinder with a gas other than for which it was certified will void the warranty and liability.

2.10.1 Operating Gas – Compressed Natural Gas (CNG)

To ensure the full functionality of the X-STORE cylinder and its components, only use CNG meeting the requirements stated.

Compressed Natural Gas (CNG) Requirements

Fuel quality is crucial to maintaining fuel system performance and life expectancy. Fuel quality is also critical for ensuring performance, life expectancy, and emission standards for vehicles and engines using the fuel from the cylinder. Compressed natural gas (CNG) fuel used in X-STORE cylinders must meet or exceed the minimum requirements of SAE International J1616 “Recommended Practice for Compressed Natural Gas Vehicle Fuel” and some fuel users may require gas of even higher purity.

In addition, CNG fuel dispensing equipment requires regular maintenance to prevent fuel system contamination from excess oil blowby, moisture, and other impurities.

 NOTICE  Failure to meet fuel requirements may result in poor cylinder performance and damage not covered under warranty.

 WARNING  Never use compressed air to clean cylinder exterior or interior or to purge cylinder contents.

 NOTICE  Oil, dust, debris (from compressors, valves, joints, and other components), and similar are considered contaminants, and can lead to damage to the fuel systems, MEGGs, and other applications.

Regularly check that all fueling components are in proper working condition.

The filling / unloading station operator is responsible for ensuring that the above-mentioned requirements are fulfilled.

2.10.2 Purging Gas – Nitrogen (N2)

Table 2‑4: Nitrogen (N2) Requirements




≥ 99.8 Vol.%

Maximum concentration of individual contaminants

Water (H2O)

≤ 40 ppmv/v

Oxygen (O2)

≤ 100 ppmv/v

2.11 Filling/Unloading Station Requirements

The following requirements are not intended to be a CNG filling/unloading station design guideline or a design, concept, or planning reference. All applicable legal provisions, standards, codes, and engineering best practices must be observed and will prevail over the following requirements.

2.11.1 Filling and Unloading Requirements

Ensure that the following filling and unloading settings/conditions are met at all times during the respective procedures:

1. Filling station compression system must not exceed the maximum developed pressure specified in 8.1 "Operating Parameters."

 WARNING  Risk of severe injury or death due to excessive pressure.

Pressure peaks must not be permitted.

2. When defueling/unloading, always maintain minimum cylinder residual pressure as specified in 8.1. "Operating Parameters."

 NOTICE   Negative pressure or vacuum is not permitted; risk of cylinder damage.

3. Temperature of gas delivered at the gas connector coupling never exceeds the operational limits specified in 8.1. "Operating Parameters."

4. If filling from a static system with fixed volume (e.g., a buffer) or unloading to such a system, the total volume—the sum of the static system volume and the cylinder volume—must be calculated.

 Final pressure depends on the total volume.

Both volumes will reach the same pressure (equalize) at the end of the process.

2.11.2 Gas Connection

Ensure that the gas connection meets the following requirements at all times:

1. Filling/unloading point connection is compatible with XSTORE cylinder connections.

2. Filling/unloading hose is not excessively stretched (creating tension on the connectors) nor too loose (causing the hose to scrub the pavement).

3. Filling/unloading hose is equipped with a built-in venting system.

4. Filling/unloading hose is equipped with a safety breakaway device according to ISO 19880‑1 requirements.

5. Filling/unloading station is equipped with a gas filtering system to avoid oil, debris, and moisture contamination from the compressor and other equipment.

6. Filling point is equipped with a pressure gauge indicating the pressure delivered to the filling hose, and, ideally, a delivered volume meter.

7. Filling point is equipped with a back flow prevention device.

8. Filling/unloading hose must be secured by means of a tether to prevent the hose from recoiling in case it is not properly connected to the gas connector.

2.11.3 Ventilation Requirements for Enclosed Working Spaces

Ideally, cylinder filling, unloading, and service is to be performed outdoors. However, if any of these procedures must be performed in an enclosed working space (Figure 2–5), ensure that the following ventilation requirements are fulfilled at all times during the procedure:

1. Vent cylinder(s) before moving into an approved enclosed working space.

 WARNING  Venting procedure must be performed outdoors only. CNG may accumulate when vented indoors and potentially ignite.

2. The enclosed work space is provided with a good ventilation rate.

 NOTICE  Natural ventilation is recommended.

 WARNING  Full ATEX conformity required for equipment for air displacement in working spaces with mechanical ventilation.

3. Roof constructions have no gas traps and ventilation roof windows, exhausts, or similar are installed and properly functioning.

4. All electrical wiring and devices used in and around the working space are non-sparking.

5. No open flames are produced within the working space.

6. No tools, appliances, or heat sources with hot surfaces are used in the working space.

Figure 2–2: Ventilation of Enclosed Working Spaces


gas traps


ventilation roof windows


2.12 Tools and Consumables for Operation and Routine Maintenance

The following tools and consumables must be available for cylinder operation and routine maintenance.

Table 3–5: Tools and Consumables for Operation and Routine Maintenance


leak detection fluid (in a spray bottle)

gas detector (equipped with the appropriate probe)

infrared thermometer

small telescopic mirror

ATEX approved lamp / flashlight

depth gauge

2.13 Required Actions After a Traffic Accident or Thermal Event

2.13.1 Traffic Accident

If an X-STORE cylinder has been involved in a traffic accident (damage to the vehicle frame), the cylinder must be tested by Hexagon Agility or an authorized partner to determine whether it may be returned to use.

Please provide Hexagon Agility with all available accident documentation including photos.

 WARNING   Immediately remove cylinder from operation until proper testing can be conducted.

2.13.2 Thermal Event

If a cylinder has been involved in a thermal event such as fire, it must be condemned and disposed of as described in Chapter 9.

2.14 Relevant Standards

Observe the following standards* for operation of CNG cylinders and systems:

  • ISO 11439
  • ISO 11119-3
  • EN 12245
  • 2010/35/EC and ADR

*Hexagon Agility cannot anticipate every use case for X-STORE CNG cylinders; Owner/User is responsible for complying with all applicable standards for the application of their choice.

3. Description

3.1 Cylinder Function

The X-STORE cylinder is designed to store compressed natural gas (CNG).

3.2 Cylinder and Component Composition

X-STORE cylinders are Type 4 cylinders constructed from a plastic liner and metallic bosses overwrapped in with composite laminate.

Figure 3–1: Cylinder Cutaway Showing Components


composite laminate






valve adapter

4. Transport, Handling, and Storage

4.1 Cylinder Transport

 NOTICE  Transporting and handling cylinders without pressure is not allowed.

X-STORE cylinders are shipped with a maximum of 2 bar / 30 psi at a temperature of 20° C (68° F). Pressure is only allowed to go below this minimum level for service proposes for a maximum of 48 hours without valve/adapter.

If cylinder pressure is discharged for any reason, the cylinder with mounted valve/adapter should never be stored without pressure for longer than 3 months. To avoid damage to the liner during these 3 months, store the cylinder open to atmosphere with the valve OPEN.

If the cylinder is to be stored for a longer period (more than 3 months), the cylinder must be pressurized up to 2.5 bar / 36 psi. Filling a cylinder that was open to atmosphere must be carried out according to the Section 5:1 “Initial Filling Procedure.

4.2 Cylinder Handling

 NOTICE   Possibility of damaging the cylinder in a manner that is not readily visible.

Never lift cylinders at the valves.

Ensure that no impact load may occur; e.g., do not let the cylinders roll off the transport pallet.

Do not stack items on the cylinders.

 CAUTION   Possible injury from loose fiber ends; wear protective gloves.

4.3 Cylinder Storage

When storing cylinders, observe the following requirements:

1. Only store the cylinder in the original packaging.

2. Protect cylinders against ultraviolet (UV) radiation.

3. Secure cylinders against rolling or sliding.

4. Store cylinders in a horizontal position.

5. If valves or adapters are screwed into the cylinder, close any openings with plastic plugs.

6. The surface of the cylinder must be protected against abrasion during transport and storage.

7. Store cylinders in a well-ventilated location. If cylinders are stored using CNG or RNG to maintain pressure, apply a label indicating: “CNG (compressed natural gas) UN 1971 pressure 250 bar / 3600 psi”.

Figure 4–1: Caps (1) or plugs should remain on the valve (2) during cylinder storage.

5. Filling, Mounting, and Installation Procedures

5.1 Initial Filling Procedure

When initially filling a cylinder from ambient pressure, a special “Cold Fill Procedure” (Section 5.1.1) must be followed in order to prevent damage to the cylinder. The same procedure must be used any time the pressure / temperature combination falls within the red area of Table 5–1 below, or the cylinder is depressurized for maintenance such as replacing a valve.

Table 51:    CNG Percentage Fill Chart*

The following steps must be followed closely:

1. Prior to initial filling, the cylinder must have a constant and stable temperature of 15 °C (59 °F) or higher.

2. Filling must take place slowly, smoothly, and carefully. The rate of filling from the start of the procedure to 20 bar (290 psi) must never exceed 0.5 bar (7 psi) per minute and should take approximately 40 minutes.

3. Perform a Leak Check before continuing with the fill procedure.

4. As soon as the pressure has increased above 20 bar (290 psi) the fill rate can be increased.

5. Monitor cylinder surface temperature using an infrared thermometer as the temperature inside the cylinder increases during filling.

 NOTICE  Do not allow the surface temperature of the cylinder to exceed +65 °C (149 °F).

After the initial filling procedure attention must be paid to the pressure. Allowing the pressure / temperature combination to fall in red area of the above graph is prohibited and the Initial Filling Procedure must be performed again.

Handling and transportation of the cylinder is prohibited when the pressure / temperature combination is in the red area of the graph above. In addition, please follow all local regulations concerning maximum pressure permitted for transportation.


5.1.1 Cold Fill Procedure

Special fuel fill procedure required for filling cylinders and MEGCs at low cylinder pressures from 0.07 to 10.2 bar (1 to 149 psi) AND at temperatures below −12 °C (10 °F).

1. Consult Table 5–2 “Filling Reference Chart” to verify the proper Filling Procedure to use:

Table 52:    Filling Reference Chart

Filling Reference Chart

IF . . .

THEN . . .

Manifold Pressure Gauge Reading



Filling Procedure to be followed

0 bar / psi or lower

−40 °C to 82°C

(−40 °F to 180 °F)

Condition cylinder @ 15 °C / 60 °F for 8 hours.

 NOTICE  Initial gas fill flow rate must be ~0.5 bar (~7.2 psi) per minute or less until 

15 bar (217 psi) is reached.

0.07 to 10.2 bar

(1 to 149 psi)

Below −12 °C

(10 °F)

Condition cylinder @ 15 °C / 60 °F for 8 hours

before filling

 NOTICE  DO NOT directly fill a low-pressure cylinder at cold temperature from a high-pressure cylinder, cascade, or station. This can cause liquid natural gas to form which may damage the cylinder liner.

2. Refer to Table 5–1 “CNG Percentage Fill Chart” to determine the maximum gas pressure possible for the cylinder or MEGC given the ambient temperature.

3. ONLY fill cylinder directly with a compressor to 31 bar ± 3 bar (450 psi ± 50 psi).

 NOTICE  Never fill cold cylinders using a cascade system or line pressure.

4. Wait at least 1 hour.

5. Proceed with filling or defueling/unloading procedure as appropriate.

5.2 Valve Installation

5.2.1 Installing Valves

Use only Hexagon Agility approved valves and pressure relief devices (PRDs) with X-STORE cylinders. Please contact Hexagon Agility FleetCare to obtain Hexagon Agility Genuine Parts.

 NOTICE   The X-STORE cylinder, when delivered with a valve, has been designed, constructed, and certified to be used with a specific valve. Replace valves only with Hexagon Agility Genuine Parts.

Cylinders require careful handling to avoid damage.

 WARNING  STOP valve installation immediately if any impact, drop damage, or other visible defects are detected. Any damage must be evaluated per Section 7.3), recorded, and reported to Hexagon Agility as soon as possible.

1. Remove dirt from valve, adapter, and mounting surfaces with a clean cloth.

2. Use the appropriate valve removal/installation tool to remove the valve; ensure no old PTFE tape gets into the cylinder.

3. Clean and valve fitting threads and the cylinder fixed end mount bearing surfaces and inspect for damage; replace any damaged parts.

Figure 5–3: Cylinder valve with PTFE tape (1) applied to cylinder port threads (2).

4. Wrap valve threads with PTFE tape.

5. Install valve using appropriate OEM installation/removal tool until it is fully seated into the valve adapter.

Figure 5–4: Cylinder valve (1) and valve adapter (2) with valve OEM installation/removal tool (3).

6. Use the appropriate OEM installation/removal tool to torque the valve to 180 Nm (133 ft-lbs).

 NOTICE  Torque valve adapter to 400 Nm (295 ft-lbs). Applying a torque greater than 400 Nm (295 ft-lbs) to the cylinder is not permitted.

7. Mark the transition from valve to the cylinder with a drop of sealing wax/paint.

8. Record valve replacement including the OEM serial number in appropriate documents (vehicle log book / maintenance book; see national regulations or vehicle documents).

9. Test the cylinder / adapter / valve assembly and/or system for leaks.

5.3 Cylinder Installation Instructions

5.3.1 Neck Mounting

X-STORE cylinders are designed for neck mounting with a fixed bearing side on the valve end with valve and a floating or sliding bearing side opposite.

5.3.2 Vertical Mounting

X-STORE cylinders have been specifically designed to be installed and used in a vertical position.

5.3.3 Valve Adapter

X-STORE cylinders are equipped with an adapter for neck mounting. The adapter is integral to the cylinder seal and should never be removed. Removal of the adapter can lead to irreparable leakage.

Figure 5–5: Cylinder boss (1) and valve adapter (2): incorrectly removed (left); correctly installed (right)

5.3.4 Valve Adapter Sealing Wax

The valve adapter is sealed with sealing wax to indicate whether the valve adapter was disturbed during valve replacement. If the wax seal is damaged, Hexagon Agility must be consulted before using the cylinder.

Figure 5–6: Damaged wax seal (1) (left); intact wax seal (2) (right).

6. Operating Conditions

X-STORE cylinders are designed for an operating pressure of 250 bar (3600 psi) at a stabilized gas temperature of 15 °C (59 °F).

 NOTICE  Gas temperature during filling is permitted to reach a maximum of 82 °C (180 °F) for a short period. Cylinder surface must never exceed 65 °C (149 °F).

This corresponds under normal operating conditions to a maximum of 325 bar (4700 psi). The maximum filling pressure should never exceed more than 325 bar (4700 psi) at any temperature.

If the pressure is discharged for any reason and the cylinder has been opened to atmospheric pressure, follow Section 5.1.1 “Cold Fill Procedure.”

The maximum useful life is unlimited in accordance with EN 12245 / ISO 11119-3. For each standard, the lifetime is shown on each cylinder label, as well as in the cylinder documents.

Periodic inspection according to Section 7.3 must be performed.

After the expiration of the useful life, the cylinder must be destroyed and disposed of as described in Chapter 9.

7. Maintenance

7.1 Safety

7.1.1 Personnel Qualification

All work performed on CNG cylinders and components—including maintenance and inspection—must be performed by trained, authorized, and/or certified persons as required by national or local regulations.

It is essential that personnel are in possession of this service manual to ensure all important information is understood.

7.1.2 Periodic Inspections

At regular intervals, the cylinders must be tested according to ISO 11623 (EN 12245 / ATR D 1/21 / ISO 11119-3) and ISO 19078 (ISO 11439).

The periodic inspections must be carried out according to the time period stated on the cylinder label.

Independent of the periodic inspections, it is still important to check cylinders for obvious damage regularly.

 NOTICE  Small superficial cracks (refer to Section 7.3.3) on the cylinder outer circumference may be a normal part of the manufacturing process.

7.2 Cleaning

Cylinder cleaning frequency is dependent on operating conditions.

Examples of negative cylinder impairments include the following:

1. A coat of dust or mud will reduce cylinder heat transfer capacity.

2. In salty environments (coastal regions, roads treated with salt, etc.) salt accumulation will induce corrosion in metal parts.

3. Dust, sand, or other accretions on cylinder connections may potentially introduce contaminants into the cylinder and associated components.

7.2.1. Cleaning Procedure

 CAUTION  Wear protective gloves.

1. Clean cylinders with fresh, cold water ONLY; NEVER use hot water or cleaners.

2. In most cases, a gentle rinse with fresh water will be enough if done frequently.

3. For hardened dust or mud, use a damp cloth or shop to remove most of it and rinse with fresh water.

  WARNING   NEVER use hot water or a steam cleaner to clean a cylinder as a T-PRD may activate.

 NOTICE  NEVER use a pressure washer to clean a cylinder; damage and/or water intrusion may occur.

4. Dispose of used water, contaminated cloths, etc. according to local regulations.

7.3 Cylinder Inspection

While the vast majority of the cylinder manufacturing process is highly automated, some steps require manual labor resulting in small optical differences between cylinders.

The following photographs and descriptions illustrate various ways a cylinder could possibly be damaged. The guidelines are based on information provided in ISO 19078:2013(E).

7.3.1 Cylinder Inspection Procedure

1. Record and compare cylinder data with the data from logbooks (if applicable).

2. Clean cylinder according to Section 7.2.

3. Inspect cylinder surface for the following conditions:

  • Cut/scratch damage (7.3.2)
  • Superficial crack (7.3.3)
  • Abrasion marks and scratches (7.3.4)
  • Chemical damage (7.3.5)
  • Impact damage (7.3.6)
  • Loose fiber ends (7.3.7)

4. Inspect all connections and plumbing between the cylinder and valve and search for leaks (7.3.6).

7.3.2 Cut/Scratch Damage

Use a depth gauge and the following table to assess cut/scratch damage level and determine required action:

Table 7–1: Cylinder Damage Levels


Damage Category [per ISO 19078:2013(E)]

Level 1

Level 2A

Level 2B

Level 3


scratch Depth

Less than 0.25 mm (0.01-in)

Greater than 0.25 mm (0.01-in) but not exceeding 0.9 mm (0.035-in)

Greater than 0.9 mm (0.035-in) but not exceeding 1.25 mm (0.05-in)

Greater than 1.25 mm (0.05-in)

Required Action

Continue use

Contact Hexagon Agility FleetCare

Contact Hexagon Agility FleetCare

Condemn cylinder

Figure 7–1: Levels of cut/scratch damage. For cuts classified as Level 2A and 2B, please contact Hexagon Agility FleetCare.

7.3.3 Superficial Cracks

During the cylinder manufacturing process, small cracks may develop in the composite shell which do not affect cylinder function.

Figure 7–2: Cylinder composite surface exhibiting superficial cracks (arrows).

 WARNING  If cracks are in the fiber, the cylinder must be immediately removed from use and disposed of as described in Chapter 9. 

 NOTICE  Please contact Hexagon Agility FleetCare if uncertain about apparent crack damage.


7.3.4 Abrasion Marks and Cracks

Abrasion marks and scratches may occur from loose cylinder mounting straps or supports.

 NOTICE  It is crucial to determine the cause of abrasion and scratches before reinstalling the cylinder in order to avoid further damage.

Figure 7–3: Cylinder composite surface exhibiting abrasion marks and scratches.

Abrasion and scratches are permitted if the damage is limited to the resin layer, but not the first fiber layer. Refer also to damage level guidelines in Table 7.1.

 WARNING  If this type of damage affects a fiber, the cylinder must immediately be removed from use and disposed of as described in Chapter 9.

 NOTICE  Please contact Hexagon Agility FleetCare if uncertain about apparent abrasion or scratch damage.

7.3.5 Chemical Damage

Although cylinder resin coating is quite robust, chemicals such as acids may damage it. While slight discoloring that has not softened the coating is permitted, it is extremely important to locate the source of chemical exposure and eliminate it.

Figure 7–4: Cylinder composite surface exhibiting chemical damage (circled).

 WARNING  If chemical exposure has softened the cylinder coating, the cylinder must immediately be removed from use and disposed of as described in Chapter 9.

 NOTICE  Please contact Hexagon Agility FleetCare if uncertain about apparent chemical damage.

7.3.6 Impact Damage

Impacts to the cylinder may be difficult to identify and evaluate damage severity. If the affected spot shows only small signs of scratches, the cylinder may remain in use.

Figure 7–5: Impact damage (circled) on a cylinder dome (left); and cylinder body (right).

 WARNING  If the affected spot exhibits damage to the fiber or delamination, the cylinder must be removed from use and disposed of as described in Chapter 9.

 NOTICE  Please contact Hexagon Agility FleetCare if uncertain about apparent impact damage.

7.3.7 Loose Fiber Ends

Loose fiber and delamination of fiber ends are not acceptable.

 WARNING  To help evaluate the level of damage, please send a photo to Hexagon Agility FleetCare.

Damage to cylinders can lead to unravelling when broken fiber progressively delaminates from the composite surface. Figure 7–6

If there is evidence of lifted fiber without unraveling, it may be repaired.

 WARNING  If fiber has begun to unravel, cylinder must be decommissioned and disposed of.

Figure 7–6: Fiber unraveling with a section of the composite lifted.

7.3.8 Leak Test

Hexagon recommends using a leak detection spray. Testing by leak-measuring-devices (sniffer devices) may cause misleading results due to natural permeation of the gas through the cylinder composite.

Evaluate the leak test under the regulations of ISO 11119-3 and ISO 11623: the gas system shall show no leaks, i.e. stay bubble-free for 2 minutes.

 NOTICE  Small bubbles which disappear after a few seconds may appear when using leak detection spray indicate a phenomenon called “cylinder gas permeation.”

Cylinder gas permeation is distinguishable from a leak in which a bubble or foam formation and growth is visible and long in duration. Leak Test Procedure

Always test cylinder for leakage complete with valve and adapter(s).

1. Fill cylinder to labelled working pressure.

2. Allow cylinder to rest for at least 2 hours to gain stable pressure and stable temperature conditions.

3. Spray fitting connections with liquid leak detection fluid.

 NOTICE  If the cylinder is heated due to filling, the leak detecting fluid may evaporate which could cause incorrect test results.

4. Wait 3 minutes minimum.

5. Inspect for bubbles indicative of a gas leak at fitting and other component junctions.

6. Defuel the cylinder.

7. Replace any leaking components according to Chapter 5.

8. Repeat leak test beginning with Step 1 until the cylinder assembly passes.

7.4 Cylinder Inspection Checklist

The following checklist can be copied and be used for periodic cylinder inspection.

Cylinder Serial Number                       _______________________________

Year and month of initial approval     _______________________________

Date of previous inspection                _______________________________

Inspection company                             _______________________________

Name of authorized personnel            _______________________________

Examination and Test Criteria

  • Any test criterion checked "not allowed" results in a failure of the inspection.
  • After repairs to a failed cylinder, the complete checklist must be performed again.
  • Periodic inspection is considered passed when all criteria are checked “allowed”.

1.  Cracks reaching the first fiber layer?

o No ------- allowed            o Yes ----- not allowed

2.  Abrasion marks and scratches reaching the first fiber layer?

o No ------- allowed              o Yes ----- not allowed

3.  Damage-free or points of impact minimal?

o Yes ------- allowed             o No ----- not allowed

4.  Are loose fibers present?

o No ------- allowed              o Yes ----- not allowed

5.  Valve, T-PRD, and/or valve adapters damaged?

o No ------- allowed              o Yes ----- not allowed

6.  The complete cylinder and attached components are gas-tight and held pressure for at least 10 minutes?

o Yes ------- allowed             o No ----- not allowed

Cylinder is defect free and has passed a leak test.

o Yes, cylinder is approved for use.

o No, cylinder must be marked “CONDEMNED” and disposed of.*


_______________________________________                                   ________________

Signature of Authorized Inspection Personnel                                    Date



*Please notify Hexagon Agility FleetCare if a cylinder fails an inspection; supply cylinder serial number and reason for failure using the contact information provided.

8. Technical Data

8.1 Operating Parameters

Reference parameter


Gas temperature range

-40 °C to +65 °C (-40 °F to +149 °F).

Installation requirements

  • Not near explosive material
  • No ultraviolet (UV) radiation

Working pressure

250 bar (3600 psi) @ 15 °C (59 °F)

Maximum pressure

260 bar (3800 psi)

Maximum lifetime (ISO 11439)

20 years

Maximum lifetime (ISO 11119-3 / EN 12245 / ATR D 1/21 EN 17339 / ADR)

NLL (Non Limited Lifetime) or limited on label

8.2 Arid “Dry” Gas Requirements

Reference parameter


Water vapor content

< 32 mg/m3 (49 ppm)

Minimum pressure dew point at 200 bar (2900 psi)

-9 °C (16 °F)

Hydrosulphide and other soluble sulphides

< 23 mg/m3 (35 ppm)


< 1 Vol.%

8.3 Humid “Wet” Gas Requirements

Reference parameter


Water vapor content

> 32 mg/m3 (49 ppm)

Pressure dew point at 200 bar (2900 psi)

> -9 °C (16 °F)

Hydrosulphide and other soluble sulphides

< 23 mg/m3 (35 ppm)


< 1 Vol.%

Carbon dioxide

< 4 Vol.%


< 0,1 Vol.%

9. Decommissioning and Disposal

Cylinders which exhibit Level 3 damage, cannot be positively identified, or which have exceeded their lifespan, i.e. reached the “do not use after date” on the label, must be marked “CONDEMNED” (Figure 91) and scheduled for decommissioning and disposal.

 WARNING  Condemned cylinder must be rendered incapable of holding pressure; see Section 9.3.

Figure 9–1: Cylinder marked "CONDEMNED."

9.1 Venting Residual Gas from a Cylinder

 NOTICE  Hexagon Agility recommends consuming as much gas from cylinders before defueling.

 CAUTION  During cylinder venting sound level can exceed 110 dB (A).

Wear hearing protection while venting cylinder.

1. Attach a ground cable to cylinder(s) / fuel system and a known good ground.

2. CLOSE cylinder manual valve.

3. If applicable: depressurize cylinder plumbing per system OEM instructions.

4. CLOSE manual valve.

5. Slowly OPEN manual valve.

6. Wait until no more gas flows out of the cylinder.

7. Verify that all pressure has been released before attempting to remove cylinder valve; refer to DSM.0174 Secondary Cylinder Defueling Confirmation Procedure.

8. Remove ground cable from cylinder(s) / fuel system.

9. Hold manual valve OPEN for a minimum of 24 hours.

 NOTICE  Some residual gas may still be present in the cylinder. The risk of fire may be mitigated by purging the cylinder with nitrogen or water.

9.2 Remove Cylinder Valve, Valve Adaptor, Plug

1. CLOSE manual valve.

2. Slowly OPEN manual valve.

3. Wait until no more gas flows out of the cylinder.

4. Purge cylinder according to Section 9.2.

5. Empty cylinder can now be brought inside. High torque is required to remove cylinder fittings; ensuring that the cylinder surface is protected, use ratcheting straps to secure the cylinder to a sturdy work surface.

6. Remove valve using the appropriate OEM valve installation/removal tool.

7. Before reinstallation, inspect component including threads and always use new O-rings where


For further instructions regarding valve removal and service, refer to valve OEM instructions available from Hexagon Agility FleetCare.

9.3 Disable Cylinder

Using a non-electric drill, drill two or more overlapping holes 1/2-in / 12.7 mm diameter or greater completely through the cylinder wall and internal liner; refer to DSM.0087 CNG Cylinder Decommissioning and Disposal Procedure. Figure 9–2

Figure 9–2: Cylinder disabled for disposal with multiple overlapping holes (circled).

 NOTICE  Drilling of overlapping holes is best achieved utilizing different size drill bits. Drill smaller hole first.

9.4 Repurpose or Recycle Cylinder

Cylinder materials are chemically inert with minimal environmental impact apart from contributing to landfill volume.

Hexagon Agility urges repurposing or recycling for each cylinder material; observe all applicable national and local regulations.

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