EMERGENCY DISCHARGE CONTROL EQUIPMENT (§ 173.315)
‘The new requirements for emergency discharge control equipment on cargo
tanks used to transport liquefied compressed gases are keyed to the degree of
risk associated with the transportation of specific liquefied compressed gases.
The regulation specifies two types of emergency discharge control equipment —

. Passive Shut-down Equipment -Passive shut-down equipment must
shut off the flow of product without human intervention within 20
seconds of an unintentional release caused by complete separation of a
delivery hose.

. Off-truck Remote Control Shut-down Equipment -Off-truckremote
control shut-down equipment must close the internal self-closing stop
valve and shut off the engine and auxiliary power upon activation by
the person attending the unloading operation.

Each MC 330, MC 331, and nonspecification cargo tank transporting liquefied
compressed gases must have emergency discharge control equipment as
specified in the following chart:

aa: ‘CargoTank Delivery New Required Bmergency

Capacity Service Discharge Cottl Equipment

Compressed gases (Division All all None

2.2 materials) with no

Subsidiary hazard, excluding

anbydeous ammonia

Poison gases Division2.3. Al All Passive shut-down equipment

materials)

Compressed gases (Division All Otherthan Passive shut-down equipment

2.2 materials) witha metered

subsidiary hazard, ammable delivery

‘gases (Division 2.1 materials), service

and anhydrous aramonia

Compressed gases (Division 3,500 Metered -—_Off-truck remote shut-down

22materials) witha water delivery equipment

Subsidiary hazard, lammable —gallonsor service

gases Division 2.1 materials), less

and anhydrous ammonia

Compressed gases (Division Metered Off-ruek remote shut-down

2.2miaterals) witha delivery equipmentand, for obstructed view

Subsiiary hazard larumable service deliveries where permited by the

gases Division 2.1 materials), regulations an ofFruck remote

and anhydrous ammonia ‘with a query feature or passive

shutdown capability

COMPLIANCE DATES FOR NEW EMERGENCY DISCHARGE

CONTROL EQUIPMENT

‘The new regulations allow a two-year period for development and testing of
emergency discharge control technology

. MC 331 cargo tank motor vehicles manufactured after July 1, 2001,
must be equipped with emergency discharge control equipment as
specified in the chart.

: MC 330, MC 331, and nonspecification cargo tank motor vehicles
that are already in service must be retrofitted with required emergency
discharge control equipment at their first scheduled pressure test after
July 1, 2001. All required retrofits must be complete by July 1, 2006.

. MC 330 and MC 331 cargo tank motor vehicles in metered delivery
service with water capacities greater than 3,500 gallons and used to
transport flammable gases (Division 2.1 materials), compressed gases
(Division 2.2 materials) with a subsidiary hazard, or anhydrous
ammonia must be retrofitted with required emergency discharge
control equipment at their first scheduled pressure test after
July 1, 2001, or by July 1, 2003, whichever comes first.

CERTIFICATION OF NEW EMERGENCY DISCHARGE CONTROL
EQUIPMENT (§ 173.315)

‘The new regulations include specific requirements for certifying the design and
installation of emergency discharge control equipment.

. Passive Shut-down Equipment - The design for each passive shut-down
system must be certified by a Design Certifying Engineer
(DCE), The certification must consider any manufacturing
specifications for components used in the system, explain how the
system operates, and outline the parameters (such as temperature,
pressure, types of product) within which the system is designed to
operate. Installation must be performed under the supervision of a
Registered Inspector who must certify that the equipment is installed
and tested according to the DCE’s certification.

. Off-truck Remote Control Shut-down Equipment -Off-truck
remote control shut-down equipment must be installed under the
supervision of a Registered Inspector, who must certify that the
equipment is installed according to the original component
manufacturer's specifications.


. After unloading, you must visually examine for defects that portion
of the hose assembly that was deployed for the delivery.

ATTENDANCE REQUIREMENTS (§ 177.834 and § 177.840)

. If you are unloading liquefied compressed gas, other than liquefied
petroleum gas (LPG) or anhydrous ammonia, from a cargo tank, you
must remain within 25 feet of the cargo tank, and you must have an
unobstructed view of the cargo tank and delivery hose to the maximum
extent practicable during the unloading operation.

. If you are unloading LPG or anhydrous ammonia from a cargo tank in
metered delivery service, and the cargo tank has a capacity of 3,500
water gallons of less, you must remain within 150 feet of the cargo
tank and within 25 feet of the delivery hose during the unloading
operation. You must also observe both the cargo tank and the
receiving container at least once every five minutes.

. If you are unloading LPG or anhydrous ammonia from a cargo tank in
metered delivery service, and the cargo tank has a capacity greater
than 3,500 water gallons, you must remain within 150 feet of the
cargo tank and within 25 feet of the delivery hose during the
unloading operation. You must also have an unobstructed view of the
cargo tank and delivery hose to the maximum extent practicable. If
your view of the cargo tank and delivery hose is obstructed, the cargo
tank must be equipped with an emergency discharge control system
that operates without human intervention or an off-truck remote
control system with a query feature that will automatically shut down
unloading unless prompted every five minutes.

. If you are unloading LPG or anhydrous ammonia from a cargo tank in
other than metered delivery service, you must remain within 25 feet of
the cargo tank, and you must have an unobstructed view of the cargo
tank and delivery hose to the maximum extent practicable during the
unloading operation

NEW DISCHARGE SYSTEM INSPECTION, MAINTENANCE AND

TESTING REQUIREMENTS (§ 180.407 and § 180.416)

If you operate a cargo tank in liquefied compressed gas service, you must
perform the following new discharge system inspections and tests each month
the cargo tank is in service:

. You must visually inspect each delivery hose and delivery hose
assembly.

. ‘You must visually inspect each cargo tank’s piping system,
including fusible elements, bolts, connections, valves, and seals.
: ‘You must test all emergency discharge control devices designed to

close the internal self-closing stop valve to assure that all linkages to
the valve operate as intended.
. ‘You must check the internal self-closing stop valve for leakage.

Beginning July 1, 2000, if you operate a cargo tank in liquefied compressed gas
service, you must perform the following inspection each year the cargo tank
is in service:

. A Registered Inspector must visually inspect the delivery hose,
delivery hose assembly, and piping system while the system is under
leakage test pressure.

REJECTION CRITERIA (§ 180.416)

You must not unload liquefied compressed gas from a cargo tank if the delivery
hose or delivery hose assembly has any of these defects:

. damage to the hose cover that exposes the reinforcement;

: wire braid reinforcement that has been kinked or flattened so as to
permanently deform the wire braid;

. soft spots when the hose is not under pressure or bulging when the
hose is under pressure;

. loose outer covering;

. damaged, slipping, or excessively worn hose couplings; or

. loose or missing bolts or fastenings on bolted hose coupling
assemblies.

‘You must not unload liquefied compressed gas from a cargo tank if the piping
system has any of these defects:

: any extemal leak that is identifiable without the use of instruments;

: bolts that are loose, missing, or severely corroded;

: manual stop valves which will not actuate;

. rubber hose flexible connectors with any condition outlined above for
hose assemblies;

. stainless steel flexible connectors with damaged reinforcement braid;

. internal self-closing stop valves that fail to close or that permit leakage
through the valve detectable without the use of instruments; or

. severely corroded components of the piping system


ADDITIONAL EMERGENCY DISCHARGE CONTROL EQUIPMENT
(8 177.840)

. MC 331 cargo tanks manufactured after July 1, 1999, and used
to transport liquefied compressed gases must be equipped with a
thermal means of closure for each internal self-closing stop valve that
will activate at a temperature of 250°F. All MC 330, MC 331,and
nonspecification cargo tanks already in service must be retrofitted at
the date of their first scheduled leakage test after July 1, 1999.

ITTEN OPERATING PROCEDURES (§ 177.840)

If you operate a cargo tank motor vehicle transporting a liquefied compressed
‘22S, you must carry on your vehicle a written procedure for delivery operations.
The operating procedure must include all information relevant to the vehicle’s
emergency discharge control equipment, including the type installed on the
vehicle, For passive systems, the operating procedure must set forth the
parameters within which the passive system is designed to function. For
example, if your vehicle's emergency discharge control system is certified to
operate at or above a specific pressure or temperature, you must include this
information in the written operating procedures.


For information about other

Hazmat Publications

Write.

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Research and Special Programs Administration
400 Seventh Street, SW, DHM-50
Washington, DC 20590-0001

Fox: (202)366-7342
E-Mail: training@rspa.dot.gov
Phone: (202)366-2301

(Or visit our web site:
http://hazmat.dot.gov

Hazardous Materials

INFO-LINE

(800) HMR49-22
(800) 467-4922

COMPLIANCE ASSISTANCE GUIDE

Revised Requirements

For Unloading

Liquefied Compressed

Gases From =
Cargo Tank
Motor Vehicles

Effective July 1, 1999

@

U.S. Department of Transportation
Research and Special Programs
Administration



NOTE: This compliance assistance guide is for information only and
should not be used as a substitute for the applicable regulations.
‘The Hazardous Materials Regulations (HMR),49 CFR Parts

171-180, are available from the Government Printing Office or may

be accessed through our website at http://hazmat.dot gov.

Need help?

Call our Hazardous Materials Information Center at 800-467-4922 between the
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Monday through Friday except Federal holidays.


EFFECTIVE JULY 1, 1999

.CKGROUND

New regulations, effective July 1, 1999, imposed new requirements on
‘operators of cargo tanks used to transport liquefied compressed gases and new
procedures for unloading liquefied compressed gases from cargo tanks. The
new regulations help prevent unintentional releases during unloading of
liquefied compressed gases, assure prompt detection of unintentional releases,
and reduce the consequences of unintentional releases. Specific provisions
include:

. new inspection, maintenance, and testing requirements for cargo
tank discharge systems;

. revised unloading requirements for liquefied compressed gases,
including revised attendance requirements; and

: new requirements for emergency discharge control equipment, such as

passive systems that will shut down unloading without human
intervention and remote control devices that enable an attendant to
stop the unloading process at a distance from the vehicle.

METERED DELIVERY SERVICE (§ 171.8)

The regulations define a new term — “metered delivery service” ~ to take
account of the differences in the design and configuration of cargo tank motor
vehicles used to deliver different types of liquefied compressed gases.
“Metered delivery service” means an unloading operation conducted at a
metered flow rate of 100 gallons per minute or less through an attached
delivery hose with a nominal inside diameter of 1.25 inches or less. ‘The
regulations for unloading liquefied compressed gases in metered delivery
service differ in some respects from those for unloading liquefied compressed
gases in other than metered delivery service.

NEW UNLOADING PROCEDURES (§ 177.840)

If you are unloading liquefied compressed gas from a cargo tank, you must
comply with the following procedures:

. Prior to unloading, you must check the cargo tank discharge system,
including the delivery hose assembly and piping, to assure that it is of
sound quality, without obvious defects, and that connections are
secure. This check must be done after the pressure in the discharge
system has reached equilibrium with the pressure in the cargo tank.

1