C.Grasso

CC Team

09/14/2020

--

A

C.Grasso

CCG Team

07/27/2020

DELETED: HP fuel filter (Manifilter) drain interval from
Maintenance table.
DELETED: HP fuel filter (Manifilter) drain interval from
text
CORRECTED: HP fuel filter (Manifilter) element change
interval
CHANGED: HP fuel filter to “Manifilter” throughout
CORRECTED: “shut off” to “shutoff;” “high pressure” to
“high-pressure; “low pressure” to “low-pressure”
throughout
ADDED: 2081-series FMMs and additional system p/ns
CORRECTED: Typo in HP filter maintenance schedule
CHANGED: kPa and MPa units to bar
UPDATED: CNG FS inspection interval to every year
UPDATED: Hexagon branding and contact information
UPDATED: Warning & signal word flags and definitions
UPDATED: Figures 8, 21b, 24, and 33a
ADDED: Warranty and contact information
ADDED: Trademark disclaimer
REMOVED: “Preliminary” language from Figures 2 and 3

--

-

B. Witt/C.Grasso

CCG Team

07/22/2020

Initial release

ECN

REV

AUTHOR

APPROVED

DATE

DESCRIPTION

Preface
This manual is designed as a supporting document to mechanics and operators trained in the operation
procedures and maintenance of the compressed natural gas (CNG) fuel system provided by Hexagon® Agility®.
No attempt shall be made to fill, install, or maintain this system until this manual and all referenced supporting
documentation have been read and fully understood.
Original Equipment Manufacturer (OEM) replacement parts may be obtained by contacting Gillig.
All replacement parts must adhere to the accepted standards and ratings as specified by Hexagon® Agility®. The usage of any
part that is not approved by Hexagon® Agility® is not recommended and may compromise the integrity and safety of the
system.

Do not remove components from original packaging until absolutely necessary. Any components that are to be reinstalled
must be thoroughly cleaned, inspected, and stored in a satisfactory manner until reinstallation.
Hexagon Agility endeavors to maintain a comprehensive and accurate product and service information. We reserve the right to make changes at any time
to manuals and other materials. Please contact Customer Care and Technical Services to ensure you have the latest version.

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Acronyms
AGA

American Gas Association

HP

high-pressure

ANSI

American National Standards Institute

LP

low-pressure

ASM

assembly

NFPA

National Fire Protection Association

BOM

bill of materials

NGV

natural gas vehicle

CAN

National Standards of Canada

nm /hr

CGA

Compressed Gas Association

OEM

original equipment manufacturer

CNG

compressed natural gas

PRD

pressure relief device

CSA

Canadian Standards Association

FMM

fuel management module

3

normal cubic meters per hour

psi

pounds per square inch (lb/in2)

SCFM

standard cubic feet per minute

1. Safety
In the interest of ensuring the safety of all personnel involved with CNG fuel storage systems, this section outlines
general guidelines that must be adhered to when operating and servicing equipment provided by Hexagon®
Agility®. Please observe the procedures and recommendations below.

1.1. Warning Messages and Symbols used in this document
DANGER indicates a hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING indicates a hazardous situation which, if not avoided, could result in death
or serious injury.
CAUTION indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.
NOTICE is used to address practices not related to physical injury, such as best
practices or tips to help an operation or procedure go smoothly and prevent equipment
damage.
Safety Instructions indicate specific safety-related instructions or procedures.

Critical
Characteristic

Product feature directly affects:
 Safety of vehicle users, people nearby and maintenance personnel, or
 Regulatory compliance.
Manufacturing  A product feature solely used to improve manufacturability or maintain process
control.
Characteristic
 A process parameter or step that has a significant effect on achieving a Critical
Characteristic or Significant Characteristic, or maintaining material
identification/traceability.

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1.1. Qualified Personnel

1.2. Safety Equipment

CNG systems should be maintained and inspected
exclusively by trained personnel with qualifications
in accordance with the applicable codes. As with all
pressure vessels, CNG storage and fuel delivery
systems are inherently dangerous.
Individuals involved in any aspect of CNG fuel
system maintenance,
emergency response,
servicing or testing must be properly trained.
Individuals who are not trained are not permitted to
service, maintain, test, or inspect a system.

Observe all recommendations below
operating or servicing a CNG fuel system.

when

1. CNG safety signage should be visible at all
applicable locations as stipulated by federal,
state, and municipal law.
2. Natural gas rated fire extinguishers should be
accessible and visible throughout all servicing
and fueling areas. Be sure that fire extinguishers
are charged, up to date, and rated correctly.
3. In case of emergency, self-contained breathing
apparatus should be on site in an easily
accessible area.
4. Areas designated for CNG fueling systems must
have adequate lighting that complies with NFPA
code.
5. Personal protective equipment (PPE) including
protective footwear and eyewear should be worn
by all personnel in proximity to a CNG system.
6. When locating the source of a leak only use a
certified leak detecting solution such as
Swagelok® Snoop®. Any other product or
solutions are unacceptable.
7. Only use tools that are in good working order with
proper calibration.
8. Wear appropriate attire while servicing or
maintaining any CNG system.

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1.3. General Safety Precautions
Observe all recommendations below
operating or servicing a CNG fuel system.

1.4. CNG Vehicle Safety Precautions
when

1. Follow all maintenance procedures in the order in
which they are written, do not skip steps unless
with explicit permission.
2. Never use an open flame as a source of
illumination in proximity to a CNG system. Natural
gas is both volatile and explosive.
3. Any process or procedure that generates sparks,
flames, or heated particles should not be applied
in areas designated for CNG.
4. If a CNG system does require a process or
procedure that generates sparks, flames, or
significant heat, conduct the procedure in an
isolated area and make sure that the CNG system
has been completely purged with an inert gas.
5. CNG fuel delivery systems are to be serviced in
designated areas that comply will all federal,
state, and municipal laws and regulations.
6. CNG servicing and fueling areas must be well
ventilated as stipulated by federal, state, and
municipal law.
7. Perform all maintenance and service procedures
in a dust free environment.
8. Never attempt to depressurize or vent a system
by loosening a fitting.

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Strict compliance with proper safety and handling
practices is essential when operating this CNG fuel
system.

The following safety precautions are vehicle specific
and should always be observed when operating
CNG fuel systems and equipment:
1. A portable fire extinguisher must be installed on
the vehicle in an easily accessible location.
2. Do not start engine if a CNG leak is detected!
3. Verify all systems are grounded before
transferring CNG fuel from one vehicle to another.
Transferring CNG may cause a buildup of static
electricity which could discharge and ignite the
fuel.
4. Never attempt to open system components that
are under pressure.
5. System pressure must not exceed 3600 psi (250
bar) @ 70°F (21°C) for other vehicles.
6. Do not smoke or produce an open flame within 30
feet (9 m) of a CNG vehicle or a CNG
dispensing/filling station.
7. Always ground vehicle prior to defueling.
8. If a CNG vehicle will be out of service for an
extended time, turn the quarter turn manual
shutoff valve to the “OFF/CLOSED” position and
run the engine until it stalls. This consumes
residual fuel in the closed off lines.

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1.5. Codes and Compliances

1.6.1. General Information

For complete and detailed information concerning
CNG codes and regulations please refer to the
following:

The CNG fuel storage cylinders are housed in steel
frames bolted to the roof. These structures are
designed to protect the cylinders in the event of a
collision. Each individual cylinder has a valve at one
end which allows fuel in that cylinder to be isolated
from the rest of the fuel system. During regular
operation, all cylinder valves are open. Additionally,
the fuel management module (FMM) is equipped
with a 1/4-turn manual shutoff valve which isolates
the fuel storage system from the engine for
emergency situations.

USA: NFPA 52, FMVSS 304
Canada: CAN/CGA B109
North America: ANSI/AGA NGV 3.1 / CGA 12.3 and
NGV 12.3-M95

1.6. First Responder Guide
For
comprehensive
emergency
response
procedures, refer to Agility publication ENP-084,
“First Responder Guide: CNG and LNG Vehicle Fuel
Systems.”

A vehicle equipped with natural gas must display a
blue reflective decal on the rear of the vehicle
identifying the fuel as compressed natural gas
(CNG) or liquid natural gas (LNG). Figure 1

1.6.2. Vehicle Fire Procedures
In the event of a CNG fire it is imperative that the
vehicle operator acts quickly and efficiently by
observing to the following steps:
1. Turn off engine and set parking brake.
2. Get passengers out of vehicle as quickly as
possible.
3. Evacuate the area.
4. Call 9-1-1.
5. Notify attending emergency personnel the vehicle
is a CNG vehicle.
6. If possible and only with the proper training:
Extinguish fire using an appropriately rated fire
extinguisher.

Figure 1. CNG blue diamond decal.

Natural gas possesses unique hazards that are not
present in gasoline or diesel fuel. The primary
concern is that CNG is in a gaseous state at room
temperature and stored at 3600 psi (250 bar).
Hexagon® Agility® minimizes these potential hazards
through state of the art design and testing practices.

A CNG fire is like a gasoline fire. However, if the fire
is not extinguished quickly, CNG cylinder pressure
relief devices (PRDs) may activate to relieve excess
pressure from the cylinders.

PRDs activate at 230°F (110°C) and will cause CNG
to exit rapidly from the storage tanks. Escaping
CNG may ignite and add to the fire.

1.6.3. Return to Service Inspection
If the vehicle has been subjected to a fire or collision,
the fuel storage system must be inspected by a
qualified inspector before it can be returned to
service.

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1.6.4. Emergency Manual Shutdown Procedures

Figure 2. Emergency manual shutdown procedure.

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1.6.5. Emergency Response

Figure 3. Emergency response procedure - precautions.

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2. System Schematics and General Assemblies
This section illustrates general schematics and high-level assembly drawings. All figures and illustrations are
intended for reference only.

Figure 4. Electrical schematic.
Table 2.Connector pin outs

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Table 3. Electrical BOM

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Figure 5. CNG fuel system schematic – electric solenoid cylinder valves.

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Figure 6. CNG fuel system schematic – manual cylinder valves.

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37

39

38

40

31

7
5

22

25
1

4

28

3

6

30

2

27

32

26

29

11

33

11

12

17
34
20
35

35
9
18

36

21
1

15

10
13
1

40

38

19

16
14

Figure 7. Fuel Management Module (FMM) components, exploded. (Refer to Table 4).

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Table 4. Fuel Management Module (FMM) components (refer to Figure 6.)

Item
1
2
3
4
5