Cylinder Filling Plants and Bulk Transfer Facilities For Depots and Filling Plants
Cylinder Filling Plants and Bulk Transfer Facilities For Depots and Filling Plants
Cylinder Filling Plants and Bulk Transfer Facilities For Depots and Filling Plants
DEP 30.06.10.14-Gen.
February 2013
DEM1
PREFACE
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International B.V. (Shell GSI) and, in some cases, of other Shell Companies.
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TABLE OF CONTENTS
1. INTRODUCTION ........................................................................................................ 4
1.1 SCOPE........................................................................................................................ 4
1.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS ......... 4
1.3 DEFINITIONS ............................................................................................................. 4
1.4 CROSS-REFERENCES ............................................................................................. 7
1.5 SUMMARY OF MAIN CHANGES ............................................................................... 7
1.6 COMMENTS ON THIS DEP ....................................................................................... 7
1.7 DUAL UNITS ............................................................................................................... 7
1.8 BASIC PRINCIPLES ................................................................................................... 8
2. CYLINDER FILLING AND STORAGE ....................................................................... 8
2.1 GENERAL ................................................................................................................... 8
2.2 DESIGN, LAYOUT AND CYLINDER FILLING EQUIPMENT ..................................... 9
2.3 BUILDINGS ............................................................................................................... 11
2.4 CYLINDER STORAGE ............................................................................................. 12
2.5 MOVEMENT OF CYLINDERS.................................................................................. 13
2.6 SPECIAL HANDLING EQUIPMENT ......................................................................... 15
2.7 IN-LINE HANDLING AND FILLING EQUIPMENT .................................................... 16
2.8 WORKSHOP EQUIPMENT ...................................................................................... 19
2.9 ELECTRICAL EQUIPMENT ..................................................................................... 21
2.10 PIPING AND LAYOUTS ........................................................................................... 22
2.11 MISCELLANEOUS SERVICES ................................................................................ 23
3. BULK TRANSFER ................................................................................................... 24
3.1 LOADING/DISCHARGING FACILITIES ................................................................... 24
3.2 PUMPS AND COMPRESSORS ............................................................................... 25
3.3 METERS ................................................................................................................... 25
3.4 ODORISATION FACILITIES..................................................................................... 25
3.5 SAFEGUARDING SYSTEMS - EMERGENCY SHUTDOWN .................................. 25
3.6 FIRE SAFETY REQUIREMENTS ............................................................................. 25
3.7 BULK VEHICLE LOADING AND UNLOADING ........................................................ 28
3.8 BULK VEHICLE LOADING PRODUCT CONTROL - EQUIPMENT AND
PROCEDURES ......................................................................................................... 30
3.9 RAIL TANK WAGON LOADING AND UNLOADING ................................................ 32
4. ADDITIONAL REQUIREMENTS FOR BULK TRANSPORT BY MARINE
TANKERS AND OTHER WATERBORNE CRAFT.................................................. 33
4.1 GENERAL ................................................................................................................. 33
4.2 EMERGENCY SHUTDOWN SYSTEMS .................................................................. 33
4.3 LOADING ARMS/HOSES ......................................................................................... 34
4.4 EARTHING AND BONDING ..................................................................................... 35
5. REFERENCES ......................................................................................................... 36
APPENDICES
APPENDIX A HAZARDOUS ZONES AND APPROPRIATE PRECAUTIONS ..................... 38
APPENDIX B DRAWINGS AND FIGURES FOR DEPOT AND FILLING PLANT
INSTALLATIONS ............................................................................................ 51
APPENDIX C METHOD OF ESTABLISHING THE DIFFERENTIAL PRESSURE
REQUIRED FOR A BULK ROAD VEHICLE PUMP ....................................... 61
APPENDIX D TYPICAL RAIL HEAD DESIGN AND LAYOUT FOR RAIL TO ROAD
LPG TRANSFER ............................................................................................. 65
APPENDIX E TERMINAL REQUIREMENTS FOR BULK TRANSPORT BY TANKERS
AND OTHER WATERBORNE CRAFT ........................................................... 66
1. INTRODUCTION
1.1 SCOPE
This DEP specifies requirements and gives recommendations for the layout, location,
safety and operability aspects of receipt, filling and dispatch facilities in LPG depots and
filling plants. LPG includes commercial propane, commercial butane and mixtures thereof.
This DEP closely aligns with DEP 30.06.10.16-Gen. that covers LPG pressure vessel
storage at ambient temperatures in fixed cylindrical vessels and spheres and
DEP 30.06.10.13-Gen. that covers LPG bulk road, rail and pipeline transportation.
This DEP does not cover;
a) LPG pressure vessel storage at ambient temperatures in fixed cylindrical vessels
and spheres
b) LPG cylinders or cartridges
c) LPG Transportation
d) Refrigerated LPG storage
e) LPG fuelling and storage at Retail sites.
This DEP contains mandatory requirements to mitigate process safety risks in accordance
with Design Engineering Manual DEM 1 – Application of Technical Standards.
This DEP (now reintroduced) was previously withdrawn in November 1994; see (1.5).
1.3 DEFINITIONS
1.3.1 General definitions
The Contractor is the party that carries out all or part of the design, engineering,
procurement, construction, commissioning or management of a project or operation of a
facility. The Principal may undertake all or part of the duties of the Contractor.
The Manufacturer/Supplier is the party that manufactures or supplies equipment and
services to perform the duties specified by the Contractor.
The Principal is the party that initiates the project and ultimately pays for it. The Principal
may also include an agent or consultant authorised to act for, and on behalf of, the
Principal.
The word shall indicates a requirement.
Term Definitions
ALARP As Low As Reasonably Practicable. The point at which the cost (in time,
money and effort) of further Risk reduction is grossly disproportionate to
the Risk reduction achieved.
CBM Conventional Buoy Mooring
Cylinder A refillable, portable pressure vessel of up to 150 litres (40 gal) water
capacity designed and manufactured to a recognised standard.
Cylinder A shut-off device, which may be self-closing or closed manually (i.e., hand
Valve wheel type), designed to isolate the cylinder from the service application.
DBV Double (interlocked) block valves associated with ERS.
Enforcing This is the authority responsible for enforcing national and local health and
Authority safety legislation and other relevant statutory requirements. (Can either be
a national body or a local authority).
ERC Emergency Release Coupling
ERS Emergency Release System; a system for quickly and safely
disconnecting with minimal product spillage, consisting of a PERC and
two isolation valves (DBVs), one upstream and one downstream of the
coupler
ESD Emergency Shut Down
ESD-1 Emergency shutdown of the transfer operation in a quick controlled
manner by closing the shutdown valves and stopping the transfer pumps.
On board ships, this stage is commonly referred to as emergency
shutdown (ESD).
ESD-1 Emergency shutdown of the transfer operation (ESD-1) and simultaneous
uncoupling of the LAs (operation of the PERC) after closure of both the
DBVs.
Evaporation Safe ground adjacent to LPG storage vessel(s) where LPG can evaporate
Area and disperse safely.
Filling Plant A place where LPG cylinders of all types are filled with LPG, tested and)
maintained, including buildings, service areas and bulk storage tanks.
Fire A material’s ability to resist a fire for specific periods of time, if tested from
Resisting either side, whilst still retaining properties of insulation, integrity and
stability.
Fire Wall A screen, wall, or dividing partition set up in open air to protect LPG
(Radiation vessels, pipes or equipment from radiated heat and to ensure enough
Wall) dispersion distance in the event of a leak from a protected vessel.
Flameproof Type of protection in which the parts which can ignite an explosive
atmosphere are placed in an enclosure which can withstand the pressure
developed during an internal explosion of an explosive mixture and which
prevents the transmission of the explosion to the explosive atmosphere
surrounding the enclosure. (Taken from IEC 60079).
GRP Glass-fibre Reinforced Plastic
GVW Gross Vehicle Weight
Hazardous Area in which an explosive gas atmosphere is present, or may be
Term Definitions
Zone expected to be present, in quantities such as to require special
precautions for the construction, installation and use of apparatus.
HEMP Hazards and Effects Management Process
High Risk A high population density within 500 m (1640 ft) of the installation, (e.g.,
Location blocks of flats) low mobility population (e.g., hospital, home for elderly) or
public building such as library, concert hall, school).
ISO International Organization for Standardization.
Large >15 Kg (33 lb)
Cylinder
LFL Lower Flammability Limit
Liquefied The generic description of liquefiable gases mainly comprising C3 and C4
Petroleum hydrocarbons.
Gas (LPG)
Mounded A storage vessel partly buried or above ground and covered by a mound
Vessel of earth or other inert material.
Nominally A cylinder that has had most but not necessarily all LPG liquid removed
Empty and still contains LPG vapour.
Cylinder
Non- Will not support combustion when tested in accordance with recognised
Combustible standards.
Material
OCIMF Oil Companies International Marine Forum
PERC Powered emergency release coupling
PLC Programmable Logic Controller - is a digital computer used for automation
of electromechanical processes. Unlike general-purpose computers, the
PLC is designed for multiple inputs and output arrangements, extended
temperature ranges, immunity to electrical noise, and resistance to
vibration and impact. Programs to control machine operation are typically
stored in battery-backed-up or non-volatile memory (can retain the stored
information even when not powered).
Point of The point at which liquid transfer connections and disconnections are
Liquid made.
Transfer
PPE Personal Protective Equipment
PRV Pressure Relief Valve. A device fitted to an LPG tank or cylinder which
releases pressure when a pre-set gas pressure occurs.
PTW Permit To Work
QCDC Quick Connect/DisConnect couplings
RCCB Residual Current Circuit Breaker
ROV - A shut-off valve that can be activated remotely to automatically shut when
Remotely engulfed by fire, deprived of actuating power or some other hazardous
Operated condition is detected.
Emergency
Shut Down
Valve
RTW Rail Tank Wagon
Separation The horizontal distance between a specified feature and the nearest part
Term Definitions
Distance of a storage vessel.
SIGTTO Society of International Gas Tanker and Terminal Operators Limited
Small ≤15 Kg (33 lb)
Cylinder
Underground A storage vessel buried below ground level.
Vessel
Vessel A container or tank of over 150 litres (40 gal) water capacity designed and
manufactured to a recognised pressure vessel code.
Water The water volume (in litres [gal] of water) that will completely fill a vessel.
Capacity
1.4 CROSS-REFERENCES
Where cross-references to other parts of this DEP are made, the referenced section
number is shown in brackets ( ). Other documents referenced by this DEP are listed in (5).
Feedback that has been registered in the DEP Feedback System by using one of the above
options will be reviewed by the DEP Custodian for potential improvements to the DEP.
2.1 GENERAL
a) LPG cylinder storage and filling plants vary considerably in layout and size
dependent upon the size limitations as well as the number of products being handled
and the number, size and type of cylinder filled; the method of product supply also
has a significant effect.
b) A decision should be made at the outset whether to go for minimum investment at
the start and invest further when production volume increases, or to invest in the
longer term solution from the start. This decision will be influenced by stability and
maturity of the market, cost of local labour and ability to maintain and support
advanced technology locally.
c) The smallest possible filling plant will be comprised of an LPG storage vessel and
one or more cylinder filling machines which are loaded manually with cylinders. The
next stage in size of filling plant would be to serve a number of in-line filling
machines with a chain or roller conveyor system. The largest capacity filling plants
will have carousels and chain conveyor systems. In practice at a large filling plant, a
combination of all these sizes of filling facility would be used, as there will be cylinder
types with a limited market volume that do not justify a high volume filling system.
d) The extent of automation in the design generally has a direct correlation with the
local cost of labour. All tasks associated with the handling, sorting, testing, filling and
transporting of cylinders can be automated, so that there is only the requirement for
manual intervention when a fault occurs in the system, however this is expensive.
e) As soon as it is economically viable, two or more storage vessels should be provided
for each of the products handled in order to cover emergency situations as well as
periodic inspection/testing/maintenance
f) Cylinder filling and storage may be located outdoors, on roofed plots or within
custom built filling and storage sheds.
g) Filling and storage shall be separated either by space, walls or water screens or a
combination of them.
h) When more than one product is handled, design should minimise the risk of cylinders
being filled with the wrong product.
The site shall be designed to restrict access to the general public, particularly to hazardous
zones.
Similarly, the site shall be designed to limit access to dealers, distributors, bulk Contractors
and rail operators, etc., to areas they require access only (e.g., the rail receipt area should
be fenced off to control rail operator access to the rest of the site).
2.2.2 Layout
2.2.2.1 Layout general
The layout of cylinder filling and storage facilities should be such that:
a) Good access is available for cylinder carrying vehicles.
b) Loading/unloading platforms are suitable for the number and size/type of vehicles
involved and with sufficient space for cylinders if movement is not directly from
vehicle to conveyor and vice versa.
c) There is adequate space or time for pre and post cylinder filling inspections/tests.
d) There is adequate space for the safe storage of both full and empty cylinders and
that this is segregated from filling and working areas (testing, revalving, etc.).
e) Maximum use is made of in-line facilities, i.e., location of equipment on the
conveyors, in order to minimise the movement of cylinders on and off conveyors and
minimise handling in general.
f) There is a simple/unimpeded flow of cylinders from unloading platform through
filling/working areas back to the loading area.
g) Filling facilities will be provided with a continuous supply of cylinders for filling and
that these will be quickly and effectively removed once filled.
h) Cylinder washing and painting facilities are sufficiently apart for atmospheric air
drying if driers are not provided.
i) Quick evacuation is possible in emergencies.
j) Opportunities for handling an expanded throughput are considered.
(Appendix B, Figure B.1) illustrates a basic cylinder filling plant (4 filling machines manually
loaded by an operator) handling up to about 100 domestic type cylinders per hour on a
single shift. Cylinder washing, painting and inspection and post filling checks take place at
other manual process stations.
2.2.2.3 Layout of a small sized cylinder filling plant
(Appendix B, Figure B.2) illustrates a layout for a small sized cylinder filling plant (in-line
filling system with filling machines in-line with the chain conveyor) handling up to about 200
domestic type cylinders/hr, i.e., approximately 4,000 tonnes per annum (tpa) on single shift
which includes cylinder washing, painting and inspection and post filling checks. The
conveyor is a continuous circuit designed for direct movement of cylinders from vehicles
onto it and vice versa. Expansion has been provided for by allowing space for a larger
carousel and for additional large cylinder filling scales.
2.2.2.4 Layout of a medium sized cylinder filling plant
(Appendix B, Figure B.3) illustrates a layout for a medium sized cylinder filling plant
handling up to about 600 domestic type cylinders/hr plus up to about 20/30 large
cylinders/hr, i.e., approximately 10,000 tonnes per annum (tpa) on single shift which
includes in-line cylinder washing, painting and inspection and post filling checks. The
conveyor is a continuous circuit designed for direct movement of cylinders from vehicles
onto it and vice versa. Expansion has been provided by allowing space for a larger carousel
and for additional large cylinder filling scales.
As and when the economics are favourable, more sophisticated machines could be added
to the conveyor system to handle, e.g., automatic checkweighing, leak testing and
automatic cylinder identification. Similarly, the layout would not prevent the introduction of
palletisation if this were allowed.
2.3 BUILDINGS
2.3.1 Structure
Buildings should be:
• of fire resistant material
• suit local climatic conditions
• either a roof structure alone or an open sided structure with cladding. The bottom of
the cladding finishing at least 2 m (6 ft 7in) above floor/platform level (when climatic
conditions are favourable).
Where climatic conditions require closed buildings, special attention shall be given to
ventilation, gas level in air monitoring and emergency evacuation (as well as the normal
building requirements).
2.3.2 Platforms/Floors
Floor levels – Floors within filling buildings shall be no lower than ground level. Whether
floors are raised or not, there shall be no unventilated spaces or recesses below floor level
where gas could accumulate.
Floor/ground openings – Any openings in the floor shall be ventilated adequately to avoid
the build-up of LPG vapour and there shall be no pits or ground depressions in the filling
building.
Usually platforms at truck deck height are provided to facilitate loading/unloading of road
vehicles. Whether the whole cylinder filling and storage area is at platform height or ground
level, will depend on the equipment used (particularly if there is a conveyor system).
Platforms and floors should be constructed of, or surfaced with, materials suitable to
withstand the impact of LPG cylinders, e.g., concrete (special finishes with non-sparking
characteristics are not considered essential).
Pits and channels in flooring should be avoided as far as possible. Where necessary for
conveyors, etc., they shall be sloped and provided with low level passageways to the free
air for ventilation and removal of water.
Floors and channels should be sloped to facilitate water draining both for washing down
and testing of water spray systems.
2.3.3 Ventilation
Adequate ventilation at floor and eaves level is essential. If natural ventilation is insufficient,
forced draught ventilation should be applied. The capacity should be based on the
requirement that under normal operating conditions, the air will never contain more than
25 % LFL.
In large throughput plants in which filling capacity may be concentrated in small areas, e.g.,
carousels, extractor systems in such areas should be considered even when open-sided
structures are used.
Filling buildings shall have the following ventilation:
• In buildings with one open side - Low level vents in the opposite wall of at least
1.5 % of its surface area.
• In buildings with weather protection or other shutter systems – Filling shall
only be carried out when shutters are open, and filling operations shall shut down
automatically, with electric interlocks, if the shutters are closed.
• In buildings with no open sides – Floor level vents shall be provided (1.5 % of
wall area) combined with a ducted extractor fan system. The ducted fan system
shall draw evenly from the filling points with sufficient capacity to disperse LPG
vapour quickly enough to a safe height in the outside atmosphere and prevent it
ever rising above 25 % of the Lower Flammability Limit (LFL) under any conditions
in the ducting. The fan motor shall be suitable for Zone 1 operation and electrically
interlocked with the LPG supply to prevent unventilated filling.
• In buildings with two or more permanently open sides – No additional
ventilation is needed.
2.3.4 Fire resistance
All parts of a filling building structure shall be constructed of non-combustible material. Side
walls shall be fire resistant (Tested in accordance with ISO 834-1:1999) to a standard of at
least 2 hours.
2.3.5 Separation
Recommended separation distances are as shown in (Appendix B, Figure B.5).
2.3.6 Vehicle loading/unloading areas
All ground areas around a filling hall for loading/unloading should be constructed of
concrete as best practice, but if bitumen is used, it shall be to a highway grade
specification.
For safety reasons, the number of filled cylinders held in storage should be kept within the
site storage design limits, often legally regulated by the site operating license.
Large cylinders should be stacked vertically in rows of four with gangways between stacks.
Small cylinders should be in rows of up to 4 with a gangway between each stack of 4 rows
and between any stack and the wall or fence of the area. Cylinders should not be stacked
higher than is convenient for manhandling (three or four high).
Cylinders can be stored on pallets to suit the pallet design. Loaded pallets should be
stacked in single or double rows with gangways between double rows, and between stacks
and walls or fences of the storage area. Pallets should be stacked no higher than is suitable
for the mechanical handling equipment in use, type of pallet and the stability of the stack.
Gangways between cylinder stacks shall be wide enough for manhandling cylinders and for
easy manoeuvring of mechanical handling equipment and pallets.
If trailers or semi-trailers are used for cylinder transport, these can be used as storage
units.
Overhead mono-rail conveyors have been used in the past particularly with capped
cylinders but with the switch to shrouded cylinders, the advantages of the powered
chain conveyor, and their high maintenance cost has resulted in their almost total
replacement.
b) Gravity Roller Conveyors
These conveyors are provided with seamless steel rollers, having ball bearings and
with a roller pitch to suit the diameter of the cylinders. Conveyor slope varies with
the conditions, but as a general rule for straight sections, a slope of 3 % - 4 % for
empty and 2 % - 3 % for full cylinders can be assumed which should be increased
by up to approximately 50 % for bends.
Adjustable supports are recommended to allow for adjustment of the slope of the
various sections in a gravity roller conveyor installation.
If different types of cylinders have to be handled on the same conveyor, it is
recommended to choose slopes matching the cylinders with the major offtake.
Small sections of horizontal roller conveyors are normally used in mechanised
plants at the filling points.
c) Portable Conveyors
Portable roller conveyors can be used and are particularly useful for
loading/unloading trucks/rail cars.
d) Powered Roller Conveyors
These conveyors are of similar design to the gravity roller conveyors but are
equipped with a driving mechanism which may consist of a rotating flat roller belt
mounted under the rollers, or a chain transmission between the individual rollers.
Powered roller conveyors are normally used in combination with gravity roller
conveyors in order to avoid steep slopes which can cause cylinder instability
problems.
e) Powered Chain Conveyors
Powered chain conveyors consist of chains running in U sections located between
outer guides. The chains may slide on the steel U section in which case they are
noisy. Lubrication is necessary (soap solution) or the chain may slide on a plastic
friction plate which rests on the bottom of the U section.
1, 2 or 3 adjacent chains are used depending on the range of cylinder foot ring
diameters which have to be accommodated.
Driving units fitted with tensioning units draw the chain by sections. The number of
driving units is determined by the layout required and the load to be carried.
Chain conveyors are frequently assembled in channels in the floor thus minimising
the effort of loading and unloading them. They are also used on the floor and in
structures at convenient height above the floor.
Powered chain conveyors are advantageous because they cope with changes in
elevation and because cylinders on them may be stopped/held at any point in the
circuit without stopping the conveyor itself and thus, without stopping the
movement of other cylinders in other parts of the circuit.
The use of a powered chain conveyor facilitates the direct movement of cylinders
from transport vehicle to filling and handling facilities and vice versa. Also powered
chain conveyors facilitate the use of in-line equipment such as washer/brushing
units, painting booths and testing machines, thus minimising cylinder handling on
and off the conveyors and assisting in a smooth flow through the plant.
f) Telescopic Conveyors
These powered conveyors are used to facilitate the movement of cylinders on and
off trucks and when used, are usually in conjunction with powered conveyor
circuits.
2.5.5 Conveyor safety
Powered conveyor start buttons should be located to ensure safe operation. Stop buttons in
a clearly marked and easily accessible location should be duplicated to facilitate emergency
stoppage.
Additionally, powered conveyors should be protected with automatic self-stoppage devices
to limit excessive damage in cases of overloading, breakdown, etc.
All drive units, motors and gears shall be protected by covers to prevent contact with
operators. Removal of the covers shall shutdown the power to the motors.
Such washing machines can only handle the routine cleaning of normal cylinders. Small
numbers may require additional manual treatment off the conveyor.
Washing machines are normally placed in-line (over the conveyor) close to the unloading
platform and before the point where cylinders are checked and segregated.
Depending on climatic conditions and also the position of the washing machine with respect
to the repainting machine, drying may be required. Hot air is normally used.
2.7.3 Painting
Painting is normally done by semi- or fully-automated equipment. Semi-automated painting
units are typically a ventilated cabin incorporating a rotating table. Cylinders are fed to this
cabin by means of conveyors and using a manually-operated spray gun, the operator
applies paint to the rotating cylinders.
Fully-automated painting units are continuously fed via conveyors and cylinders painted
automatically on a rotating table by means of spray guns. The cabin is either forced
ventilated and/or provided with a water curtain to remove the excess paint. Thick layers of
paint overspray shall not be allowed to accumulate as there have been instances of self
ignition.
2.7.4 Marking
Branding and marking can be applied manually with the aid of silk screens but such an
approach is only practicable for small throughputs.
Automatically/mechanically operated machines are also available but they are sensitive to
varying cylinder dimensions, and they may have to be duplicated when there is significant
variation in cylinder types and sizes.
2.7.5 Capping/De-capping
In some markets cylinders do not have a shroud and the valve is protected by a screw-on
metal cap.
Apart from pneumatic operated hand tools, for removal of valve protecting caps, automatic
de-capping/re-capping machines are available. These machines basically consist of a
clamp to immobilise the cylinders temporarily, and a revolving head which is lowered to
unscrew or fit the cap.
2.7.6 Removal of valve sealing plugs
Before filling can start, the valve security plugs have to be removed. This operation is
normally carried out in small plants with a pneumatically-operated hand tool. For
sophisticated plants, automatic machines are available.
2.7.7 Evacuating, purging and draining
Evacuating/purging may need to be carried out before filling new/reconditioned cylinders or
cylinders returned to the plant with their valves open. Evacuation is normally carried out
with a vacuum pump, refer to (2.8.5). For purging equipment, refer to (2.8.6).
2.7.8 Filling equipment
a) Filling Machines
Electronic load cell machines that provide remote or automatic tare input, automatic
after-fill checking and self-learning from off-target filling are readily available.
Mechanical filling machines exist in a number of developing countries and
automatically shut-off when the gross filling weight is reached.
Modern filling machines automatically connect and disconnect from the cylinder.
Some machines are manually connected and automatically disconnect. (See
(Appendix B, Figure B.4) for modern filling machines on a carousel).
The accuracy of the filling machines should be in accordance with the tolerances
permitted by the local Weights and Measures Authorities. Filling tolerances should
be within ± 50 g (1.764 oz) for the 26.2 litre (6.9 gal) type cylinders and ± 100 g.
(3.528 oz) for the 108 litre (28.5 gal) type.
(Appendix B, Figure B.6.1) and (Appendix B, Figure B.6.2) indicate capacities/filling
times of stationary and carousel mounted filling machines. These Figures are based
on machines commonly used in the LPG Industry. When procuring new machines,
advice should be sought from Suppliers as the latest machines and carousels have
higher throughputs.
Filling scales may be equipped with single filling hoses/valves or with two filling
hoses/valves, the latter to cope either with pre-filling or with cylinders equipped with
different valves.
b) Filling Valves/Heads
Filling valves/heads are available in many variations to match the different cylinder
valves in use. They may be manual or of the mechanical/pneumatically operated
type. Automatic/mechanical/pneumatic filling valves should be of the fail safe type,
so that in the event of failure of the actuating medium, (e.g., loss of air pressure), the
filling valve remains connected and prevents escape of product from the cylinders
and the filling system.
c) Filling Hoses
Refer to ISO 2928.
d) Carousels
The use of a carousel enables large filling capacities to be handled by a minimum
number of operators.
As shown in (Appendix B, Figure B.4), carousels consist of a circular steel frame,
with filling scales positioned around its periphery, having supporting wheels, a driving
unit and a central control column for the supply of LPG and air.
The speed of rotation is variable as is the number of scales to be mounted on the
platform. Provided the latter is sized correctly at the outset, a wide variation of filling
capacities (increasing throughputs) can be coped with.
Carousels are normally fitted with automatic units for moving cylinders from the
supplying conveyor onto the filling scale as it reaches the appropriate position and
for moving the filled cylinder back onto the conveyor system.
The plant design shall be such that units associated with the filling equipment such
as leak detection machines, are capable of operating at the same rate as the filling
equipment. In some instances, this may require duplication/replication of the
associated numbers of a particular type of equipment.
2.7.9 Automatic inlet and outlet devices
a) Inlet Devices
The inlet device is mounted at the end of the conveyor at the entrance to the filling
carousel. This device is provided with stoppers and arms which push a cylinder onto
the platform of a filling scale as it reaches the correct position. If the platform is
occupied, the cylinder is held on the conveyor.
b) Outlet Devices
The outlet device pushes cylinders from the carousel to the conveyor as the filling
scale reaches the appropriate position. Unless the cylinder is correctly filled and
disconnected, the ejection system is designed not to operate.
An introduction/ejection unit can be seen in (Appendix B, Figure B.4).
2.7.10 Check on filling accuracy
Equipment shall be provided to check filling accuracies by re-weighing. In addition and for
quality control purposes, a check weighing scale shall be provided to perform a periodic
random check on filled cylinder stock. Approved weights, equal to the maximum mass to be
weighed, shall be provided to check the accuracy of this check weigh scale before use. See
(2.7.1.3).
2.7.11 Leak testing after filling
a) General
Dependent on the type of cylinder-valve employed and the operating procedures
followed, leak testing of the following may be appropriate:
(i) Valve/cylinder joint
(ii) Valve seat
(iii) Spindle seals
(iv) Seals, e.g., 0-rings in valves outlets (which match with regulator connectors)
(v) Cylinder shell
For which the following methods can be used.
b) Water Test Bath
Immersion of cylinders in water allows all items mentioned above to be checked
except item (iv). Item (ii) can be tested if the valve is closed and unplugged or item
(iii) can be tested if the valve is open and plugged. This test is generally practical
only for small cylinders, such as the 26.2 litre (6.9 gal) or the 30 kg (67 lb) water
capacity type. Equipment is available for automatic and batch handling,
c) Soap Solution Test
With this manual test, using a brush and soap solution, items (i), (ii) and (iii) in (a)
above can be checked.
This method is only suitable for small throughputs.
d) Bubble - Cap Test
A bubble test cap consists of a hood, provided with a sealing sleeve, which is placed
over the cylinder valve/bung. Leakage from the valve or its joint with the cylinder
(items (i) and (ii) in (a) above) displaces the air in the hood, which then bubbles
through the water in a transparent cylinder connected to the hood indicating the
leakage. This method is only suitable for small throughputs.
e) Automatic Leak Testing Instruments
In automated filling plants, automatic instruments are normally used for leak
detection and are commonly of the hood type. Detection of leakage may be by
sensitive pressure measurement, by electrical conductance/capacitance
measurement or by flammable gas detection. Items (i) to (iv) in (a) above, can be
tested in-line by a series of machines.
2.7.12 Refitting of security nuts/plugs
This operation requires equipment similar to that described in (2.7.6).
2.7.13 Capping
This operation is carried out with the same type of equipment as described in (2.7.5) in
reversed direction.
NOTE: Cylinder reconditioning which requires hot work is not covered here, as this requires special facilities
and is normally contracted out.
2.8.2 Cleaning
Depending on the number of cylinders involved, manual or mechanical equipment can be
used for cleaning.
2.8.3 Draining
Cylinders are drained of liquid product by inverting them on a rack. They are preferably
drained through a closed system into appropriate vessels. If a cylinder is drained to
atmosphere (only done in exceptional cases), it shall be ensured that the area is safe
(adequately ventilated, supervised and that no sources of ignition are present). Complete
draining of heavy-ends, water or other deposits may require valves to be removed.
If cylinder valves are fitted with excess flow valves, then a control valve or orifice shall be
included in the system to restrict the flow to a level below that at which the excess flow
valve is designed to close.
2.8.4 De- and re-valving
This operation can be carried out manually with the aid of a clamp which holds the cylinder,
(see (Appendix B, Figure B.7)) and a manual or pneumatic hand tool. Pneumatic/hydraulic
cylinder clamps, are also available as are more mechanised valve off-and-on screwing
machines. When re-valving, the correct tightening torque should be applied to the valve.
2.8.5 Evacuation
Vacuum pumps are frequently used for the removal of air and air/vapour mixtures from
cylinders. Any vacuum pump capable of drawing a vacuum of 700 mm (27.58 in) of
mercury may be used for evacuating cylinders. The suction capacity of the pump in terms
of free air intake per hour should be about 15 to 20 times the total volumetric capacity of the
cylinders to be handled per hour. An intermediate receiver should be provided on the
suction of the pump as close to the evacuation point as possible. It shall be provided with a
vacuum gauge and a drain which discharges outside the building to a safe location. The
discharge from the pump should be fitted with a liquid trap and a vertical riser of at least
3 m (10 ft).
If cylinder valves are fitted with excess flow valves, then a control valve or orifice shall be
included in the system. This is to restrict the flow to a level below that at which the excess
flow valve is designed to close.
2.8.6 Purging equipment
The simplest purging equipment consists of a small diameter pipe, complete with shut off
valve and connection to a butane supply, which is inserted through the bung hole. Liquid
LPG (approximately 1 % of cylinders volume) is introduced to the bottom of the cylinder and
allowed to vaporise slowly and drive the air out. On completion, the exercise is often
repeated. The dip tube is then withdrawn and the cylinder valve is fitted.
Where cylinders are purged with valves still fitted, the use of a fixed purging system is
recommended, utilising a 3-way valve to introduce LPG to the cylinder. This vents it to a
venting system and closes the system down.
If purging/venting is not carried out in a closed system then a safe location and supervision
is essential.
2.8.7 Hydraulic testing equipment
Test headers can be used for the hydraulic test. Where the frequency and extent of
hydraulic testing does not justify maintaining a permanent test header, a simple manual test
pump may be connected to the cylinder by means of a suitable hose/adaptor, screwed into
the cylinder valve bung boss.
A non-return valve, with manual release, and a pressure gauge calibrated to about 50 %
above maximum test pressure should be fitted in the connecting system.
The test header incorporates: a water system for filling and draining the cylinders, a
separate hydraulic pump connection for the pressurisation and test, and additionally, a
compressed air system for speeding the drainage on completion of the test.
Such a system can be manually or mechanically operated.
hydraulically operated valve is suitable for this purpose provided the pneumatic/hydraulic
actuation lines are taken through the filling/working area and fitted with fusible elements set
to fuse at approximately 75 °C (167 °F).
Hydrostatic pressure relief valves should be provided on all lengths of pipeline in which
liquid LPG may be trapped between closed valves.
2.10.5 Flow diagram
A typical flow diagram for a filling/storage plant is shown in (Appendix B, Figure B.8).
3. BULK TRANSFER
3.1.3 Hoses
Hoses provide a low maintenance cost effective means of transfer. They should be used
with protective features such as dry-break couplings and local emergency shutdown valves
(ESDs). All hoses and hose assemblies used in LPG service/operations shall be
manufactured, tested, approved and maintained in accordance with EN 1762, EN 13766,
ISO 2928 or equivalent national standards.
The materials used in the construction of hoses and hose assemblies shall be resistant to
the action of LPG both as a liquid and a vapour. If woven wire braid is used to restrain the
hose against elongation and dampen vibrations, and heavy steel wire reinforcements are
used in the hose construction, they shall be of stainless steel. The manufacturing
specification shall clearly state the maximum working pressure. Hoses shall be
manufactured in one length without intermediate joints or couplers. All hoses shall be
electrically continuous.
3.1.4 Loading arms
The term “loading arm” refers to all metal self-supported loading and unloading arms with
articulated swivel joints and also, if required by the operation, quick connect/disconnect
couplings (QCDCs), power system (for large marine arms), control system, operational
controls, range control system, purge system, emergency release system (ERS) and jacks
(supports).
All loading arms and loading arm assemblies used in LPG service/operations shall be
approved, manufactured, tested and maintained in accordance with DEP 31.06.15.10-Gen.
3.3 METERS
DEP 30.06.10.11-Gen. shall apply.
3.6.1.3 Hydrants
These may form part of a fire protection system, provided:
a) They comply with local or regional standards.
b) Each hose line outlet has its own fire hose, couplings and combination spray and jet
nozzle. (An alternative is to install fixed monitors).
c) Enough standpipes, keys and cover lift-up levers are provided for each underground
hydrant.
d) Hydrants are spaced evenly, covering all areas with no other protection.
e) Hydrants are always easily accessible.
3.6.1.4 Manual/automatic fixed drenching systems
Requirements which shall be followed when specifying these are:
a) The firewater distribution should be a “ring main” system if justified by the risk
assessment. A “ring main” reaches all storage facilities, filling plant,
loading/unloading facilities, warehouse, workshop, offices, utilities, etc.
To achieve maintenance of the firewater distribution system without stopping the
LPG activity, there are alternative design considerations, if a “ring main” system is
not used. One example is an external seal box to maintain the availability of the fire
system in the event of a leak in the firewater system. Another is the isolation of the
main firewater pipe and using mobile fire devices during repair time. Reducing the
likelihood of water leaks can be achieved by corrosion prevention coatings. The
pipework can be flanged, threaded, clamped or gruvlocked.
b) DEP 80.47.10.31-Gen. shall be consulted when designing firewater distribution
systems.
c) The firewater distribution system components shall be installed underground in plant
areas where explosions cannot be excluded and in installations where the ambient
temperature can drop below 0 °C (32 °F) for prolonged periods. When installed
underground, placement shall be in accordance with DEP 31.38.01.11-Gen. and
materials of construction shall be glass-fibre reinforced plastic (GRP) in accordance
with DEP 31.40.10.19-Gen.
d) Loads on underground pipes (crossing roads and railways) shall be equalised by
pipe sleeves or culverts.
e) Above-ground pipes shall not be laid in pipe tracks at risk from potential spill fires.
They shall be installed with self-draining or frost protection devices and protected
from potential physical damage. Galvanised pipings shall be used throughout.
f) Manual valves shall be installed in safe zones to facilitate control of water distribution
in an emergency.
g) The system shall be tested at least monthly.
h) The quality of the water used in such systems shall be such that it will not cause
excessive corrosion.
3.6.1.5 Discharge rates
The objective is to sustain a film of water over the entire surface area, including the
supports and ends of the storage tanks. Since some water will immediately drain or splash
2
off, the drenching apparatus needs to be set to deliver at a rate of 9.8 litres/minute/m of
surface covered.
The drenching rate for application on cylinder filling points shall be a minimum of
2
7.5 litres/minute/m over the required floor area.
3.6.1.6 Fire brigade connection points
The fire protection system shall include points in safe zones for connecting fire brigade
appliances to the fixed drenching system supply.
3.6.2 Fire extinguishers
Requirements - Sufficient portable, dry powder fire extinguishers shall be provided for first-
aid protection at strategic parts of the site. Advice on size, siting, inspecting, testing and
maintenance shall be obtained from local or regional standards.
3.6.3 Detectors
3.6.3.1 Requirements
The requirement for gas or fire detection systems will depend on local legislation, site staff
levels, site location and the period of time when the site is unattended.
3.6.3.2 Type and selection
The type of detector selected shall be one which detects an emergency, activates the site
alarm and commences flow of water drench systems simultaneously. Detection systems
are highly complex, and specialist advice shall be obtained.
3.6.4 Alarms
3.6.4.1 Purpose
An alarm system shall be installed to alert all personnel on site that a problem exists, so
that everyone can undertake the actions assigned to them in the site emergency response
plan.
3.6.4.2 Audibility
Alarms shall be unmistakable and clearly audible over the area concerned and, as required,
remote control and security rooms. Site staff shall be trained to recognise and react swiftly
to the sound of the alarm.
3.6.4.3 Manual activation
Alarms can be activated in a number of ways, e.g., manually, hydraulically, pneumatically,
and electrically. Where alarm systems are manual, buttons shall be positioned around the
site at critical locations, e.g., within the filling buildings, at tanker loading/unloading points.
Their locations shall be prominently marked, readily accessible and well known to site staff.
Buttons shall be situated on the escape route from probable incident scenarios.
3.6.4.4 Automatic activation
Alarms shall be activated by fire and/or gas detectors located strategically on site.
Automatic alarms shall also have manual activation points, at least one of which shall be
located outside the storage and filling areas. Automatic alarms shall be interlocked with
shutdown devices on site so that drenching systems and LPG supply lines and pumps are
shut down as soon as the alarm goes off. At sites where interlocked systems do not exist, a
risk assessment shall be carried out to evaluate whether the existing system is acceptable
or whether improvements are required.
pressure, as specified by the Manufacturer. The cold feed to emergency showers and eye
wash units shall not be subject to unacceptable heat gains.
3.7.5 Unloading
3.7.5.1 Unloading at depots
The depot’s pump or compressor usually unloads bulk bridging vehicles. A benefit of using
a compressor is that it enables the vessel to be depressurised after the liquid contents have
been discharged, thereby increasing the quantity of product delivered.
In a number of cases, the vehicle unloading to a depot may use its own vehicle pump.
(Appendix C) gives an example of a method to establish differential pressure requirements
for a bulk vehicle pump.
3.7.6 Emergency shut-down switches
Emergency Shut Down (ESD) switches SHALL [PS] be provided close to the filling point on
escape routes, and at other locations in the vicinity which are safely accessible in an
emergency and in the control room or areas which function as a control centre.
ESD switches SHALL [PS]:
• override all other controls
• immediately stop product flow by:
o stopping the loading pumps
o closing ESD valves
o closing flow control valves (if fitted)
• actuate an alarm in the control room/area
The alarm may also be used to activate the fire pumps and open the water spray system to
the loading area. If automated flow control is installed, the in-line valve should be of a type
which closes automatically when the power is cut off, i.e., fail-safe.
3.7.7 Emergency shutdown valves
For information on ESD valves, refer to DEP 30.06.10.16-Gen., Section 3.6.
3.7.8 High and low pressure alarms
For information on High and Low Pressure alarms, refer to DEP 30.06.10.16-Gen,
Section 3.7.
3.7.9 Electrostatic precautions
For information on Electrostatic Precautions refer to DEP 30.06.10.16-Gen, Section 3.8.
3.7.10 Lightning protection
For information on Lightning Protection refer to DEP 30.06.10.16-Gen, Section 3.9.
3.8.2 Earthing/Bonding
The product flow control valve (solenoid type or electro-pneumatic) SHALL [PS] be
interlocked into the earth circuit such that flow is only permitted while continuity is
maintained between the loading/unloading facility and the vehicle. See also (2.10.3).
3.8.3 Filling
A solenoid-operated lock may be fitted to hold the loading arm/hose in the stowed position
until the correct sequence of preliminary operations has been completed prior to start of
loading.
A proximity switch should be fitted to indicate when the loading arm/hose has been
removed or disconnected and is correctly stowed after loading is complete.
3.8.4 Barrier arm
Before starting to load, the barrier arm shall be lowered to prevent the vehicle from being
driven off. A traffic light or flashing light should also be used. Once this condition has been
satisfied the loading operation can start.
As soon as the loading operation is finished, indicator lights at the loading bay should be
used to signal that all past loading procedures have been correctly executed (e.g., loading
arm properly stowed, hose disconnected, bonding link disconnected, etc.) and that the
barrier arm may be raised.
3.8.5 Weighbridge applications
A weighbridge should be provided at the loading point to directly control the amount of
product to be loaded. The process design should typically cover the following:
a. The driver or gantry operator earths the vehicle, connects the filling arm (and vapour
return) and then slowly opens the manual product valve.
b. Tare weight is taken and displayed in the control room. If a vehicle loads regularly at
the plant, the data system should include all relevant information on the vehicle, e.g.,
the water capacity of the vessel, tare weight, pressure rating. The load quantity is
then calculated based on the procedure in place for the safe filling of LPG vehicles. In
plants where reliable temperature and density information are available and are
routinely monitored, the maximum safe filling quantity SHALL [PS] be based on the
vehicle's vessel not being more than 97 % full when the loaded product is at the
Assessed Temperature for Safe Filling. The quantity ordered and maximum GVW is
also considered when calculating the load quantity.
c. Loading is initiated by the control room operator.
d. The computer controls the loading based on the predetermined weight, logs the
transaction and, as a safeguard, highlights any discrepancy beyond a specified
tolerance between the net weight calculated and the load as measured by the
weighbridge. This system prevents overfilling of the vehicle.
3.8.6 Product temperature
The temperature of the product being loaded can be measured accurately (to within 0.1 °C
or (0.1 °F)) by means of a platinum resistance probe inserted in the product supply line
close to the loading bays or at the meters upstream of each loading arm. The loading
control system monitors the probes (and all the other instrumentation devices) at regular
intervals and can therefore relate the temperature to the volume flowing through the meter
on a continuous basis. The loading control system calculates the average temperature,
thence, the volume at a standard temperature, and the safe filling volume. A risk analysis
shall be performed to identify the need of barriers to reduce as low as reasonably
practicable identified (ALARP) risks.
3.8.7 Meter applications
Coriolis mass meters with a Programmable Logic Controller (PLC) should be used. This
type of meter can measure mass flow, temperature and density directly and provide the
mass of LPG transferred plus a calculated volume at standard temperature. With the latter
system, the entire loading operation can be monitored via the gantry control system, i.e.,
pre-setting of a safe filling mass and closure of the flow control valve in the event of
abnormally low flow rates.
Consideration should be given to ‘ramping up’ the flow of product at the start of filling and
‘ramping down’ the flow of product at the end of filling.
Having recognised the driver and vehicle at the loading bay and the quantity of product to
load, and having checked that the safety interlocks have been satisfied, the control system
should release the correct meter to supply only the appropriate product. The flow of product
may then be started (solenoid valve open and pump started).
The meter pulse unit should transmit signals to the control system which records the
volume metered and detects completion of the safe filling volume for loading, at which point
the system shuts down.
For vehicles not fitted with an overfill prevention system, after completion of loading, it
SHALL [PS] be ensured that the vehicle is not overfilled by checking on a weighbridge.
3.8.8 Leaving the loading point
The control system SHALL [PS] ensure that correct disengagement of all equipment and
proper placement of loading arms or hoses into a stowed position is completed before the
vehicle can drive away.
3.9 RAIL TANK WAGON LOADING AND UNLOADING
3.9.1 General
Rail Tank Wagons (RTWs) may be loaded/unloaded by using the methods referred to in
(3.7).
A typical arrangement using a compressor is shown in (Appendix B, Figure B.10).
As the loading/unloading systems do not differ in principle from those for bulk road vehicles,
refer to (3.7.5), (3.7.6) and (3.7.7).
For protection in the event of a RTW moving away while loading arms or hoses remain
connected, (3.7.3.2) shall be applied with regard to breakaway couplings and excess flow
DEP 30.06.10.13-Gen., Section 4.2 on the automatic closure of hydraulic safety valves
shall be applied.
ESD valves SHALL [PS] be installed at the RTW siding end of the permanent piping to
contain spillage in the event of loading arm/hose failures.
Safety systems shall be set up to prevent access by other rail vehicles to the sidings while
RTWs are still connected to the loading or unloading facilities, e.g., by using barriers or
gates and a system similar to a permit to work to control communications between rail
operators and the operations of the loading or unloading facilities. This includes readiness
to enter the loading area and readiness to remove wagons.
For details on sidings, pulling equipment, capstans, mules and locomotives, etc., expert rail
industry advice shall be sought.
3.9.2 Rail heads
Sites (at which LPG transfers are made directly between RTWs and bulk road vehicles) are
referred to as rail heads. (Appendix D) shows a typical rail head design and layout.
Where transfer of LPG takes place between rail tank wagons and road tankers with no fixed
LPG storage on the site, all of (3.6) on firefighting shall apply and the other requirements of
this Section on transfer operations. Where separation distances cannot be met, a firewall
shall be used to provide the separation distance around the wall. Where the installation is
operated by a road tanker driver only, remote monitoring shall be provided. For very remote
locations where there are normally no people on the premises, no major roads or
passenger rail routes within 100 m (109 yd) of the installation (and all other requirements
above are met), a risk assessment may be performed to see if the local emergency service
4.1 GENERAL
The following documents shall apply:
• “Liquefied gas handling principles (on ships and in terminals)”, by SIGTTO;
• “Safety guide for terminals handling ships carrying liquefied gas in bulk“, by OCIMF;
• Shell Marine Manual.
The design of the cargo carrying space and product transfer facilities in LPG tankers is
based on handling either pressurised, semi-refrigerated/semi-pressurised or fully
refrigerated product.
Tanks used in transporting ambient temperature product are conventional pressure
vessels. Tankers designed to handle pressurised product are comparatively expensive to
3 3
build and are generally less than 5,000 m (176,573 ft ) cargo capacity. They are commonly
employed in coastal and short sea marketing distribution operations.
Tanks for holding fully refrigerated product are of much lighter construction, designed for
pressures slightly above atmospheric and insulated to minimise heat inflow to the product.
Tankers in this category are designed to carry cargoes between refrigerated and large
3
pressurised storage terminals. Their cargo capacity ranges from around 20,000 m
3 3 3
(706,293 ft ) to 150,000 m (5,297,200 ft ).
Semi-refrigerated/semi-pressurised tankers fill the capacity gap and meet operational
needs between the small pressurised tankers and large fully refrigerated carriers. Their
cargo tanks are designed to handle fully and partially refrigerated product at
correspondingly reduced pressures.
To avoid damage to the loading arms or to the ship (e.g., due to ship drift under adverse
weather or current conditions) a rapid disconnection of the loading arms from the ship
(Appendix E, Figure E.1) (ESD-2) SHALL [PS] be installed as well.
DEP 30.06.10.20-Gen. shall apply with respect to design and installation requirements of
both ESD-1 and ESD-2 systems at LPG export and import terminals.
ESD-1 (First Stage Emergency Shutdown System):
Terminals SHALL [PS] be equipped with an ESD-1 system to stop the transfer operation in
a quick, safe and controlled manner.
The ESD-1 system shall consist of:
a) ESD valves
b) Push buttons located at various strategic locations on the jetty and on the shore,
which are unlikely to be affected by an incident at the berth.
c) A pendant box placed on board the ship prior to loading/discharging for ships, which
are not equipped with a compatible ESD system.
d) A ship/shore link to convey the shutdown signal for ships equipped with a compatible
ESD system.
e) The ESD-1 logic control system.
ESD-2 (Second Stage Emergency Shutdown System):
Terminals SHALL [PS] be equipped with an ESD-2 system, also called the emergency
release system (ERS), to uncouple the loading arms, where fitted, quickly with minimum
spillage.
The ESD-2 system, shall consist of:
• The Emergency Release Coupling (ERC).
• Two isolation valves (the ERS valves), one upstream and one downstream of the
ERC.
• The ESD-2 logic control system.
In the case where hoses are specified, dry break couplings shall be included
4.2.3 Pressure surge
DEP 30.06.10.20-Gen. and SIGTTO “Guidelines for the alleviation of excessive surge
pressures on emergency shutdown” shall apply.
Loading arms are normally provided with an over-travel detection system. This should be a
two-stage system, particularly for the larger arms (150 mm (6 in) diameter and larger), as
follows:
a) An alarm is actuated when the arm approaches predetermined limits based upon
acceptable movements of the ship at the berth. The alarm sensor may also initiate
an ESD-1.
b) If the arm continues its movement in excess of the acceptable limits, a second alarm
will be activated and, if an ERS is provided, an ESD-2 will be initiated.
If no alarms are fitted, precautionary measures should be agreed between the ship and the
terminal to give early warning before a critical situation is reached. For guidance, refer to
the OCIMF “Design and construction specification for marine loading arms”.
5. REFERENCES
In this DEP, reference is made to the following publications:
NOTES: 1. Unless specifically designated by date, the latest edition of each publication shall be used,
together with any amendments/supplements/revisions thereto.
2. The DEPs and most referenced external standards are available to Shell staff on the SWW (Shell
Wide Web) at http://sww.shell.com/standards/.
SHELL STANDARDS
DEP feedback form DEP 00.00.05.80-Gen.
Equipment in LPG installations DEP 30.06.10.11-Gen.
Pressurised bulk storage installations for LPG DEP 30.06.10.12-Gen.
LPG bulk transfer and transportation DEP 30.06.10.13-Gen.
Pressurised bulk storage installations for LPG depots and filling
DEP 30.06.10.16-Gen.
plants
ESD systems for loading and discharging liquefied gas carriers DEP 30.06.10.20-Gen.
Metallic materials - Prevention of brittle fracture in new assets DEP 30.10.02.31-Gen.
Marine loading arms (amendments/supplements to OCIMF design DEP 31.06.15.10-Gen.
and construction specifications for marine loading arms)
Piping - General requirements DEP 31.38.01.11-Gen.
Glass-fibre reinforced plastic pipeline and piping systems DEP 31.40.10.19-Gen.
Instruments for measurement and control DEP 32.31.00.32-Gen.
Electrical engineering design DEP 33.64.10.10-Gen.
Electrical engineering design for North American application DEP 33.64.20.10-Gen.
Layout of onshore facilities DEP 80.00.10.11-Gen.
Assessment of the fire safety of onshore installations DEP 80.47.10.30-Gen.
Active fire protection systems and equipment for onshore facilities DEP 80.47.10.31-Gen.
Design Engineering Manual DEM 1 – Application of Technical DEM 1
Standards. http://sww.manuals.shell.com/HSSE/
Shell Marine Manual
AMERICAN STANDARDS
Protection against ignitions arising out of static, lightning, and stray API RP 2003
currents
BRITISH STANDARDS
IP Model Code of Safe Practice, Part 9: Liquefied petroleum gas. IP 9
Vol.1. Large bulk pressure storage & refrigerated LPG
Issued by: The Institute of Petroleum (now The Energy Institute)
EUROPEAN STANDARDS
Explosive atmospheres – Part 14: Electrical installations design, IEC 60079-14
selection and erection
Explosive atmospheres – Explosion prevention and protection – EN 1127-1
Part 1: Basic concepts and methodology
Rubber hoses and hose assemblies for liquefied petroleum gas, LPG EN 1762
(liquid or gaseous phase), and natural gas up to 25 bar (2,5 MPa) -
Specification
Thermoplastic multi-layer (non-vulcanized) hoses and hose EN 13766
assemblies for the transfer of liquid petroleum gas and liquefied
natural gas - Specification
INTERNATIONAL STANDARDS
International Safety Guide for Oil Tankers and Terminals (ISGOTT), ISGOTT 5
5th Edition
Rubber hoses and hose assemblies for liquefied petroleum gases ISO 2928
(LPG) in the liquid or gaseous phase and natural gas up to 25 bar
(2.5 MPa) - Specification
Fire-resistance tests –Elements of building construction, Part 1: ISO 834-1:1999
General requirements
A.4 DEFINITIONS
Whilst the concepts of zones and hazardous areas have been with us for many years, a
risk-based approach to hazardous areas has introduced a number of new definitions and
concepts. The zoning for dusts has been included because there are circumstances, for
example, paint overspray, which can and have produced hazards.
The temporary hazardous area has been introduced as a matter of logic and necessity.
Sources of ignition are not permitted in a hazardous area and that includes bulk and
packed vehicles which have multiple sources of ignition.
A.4.1 Normal Operation
For the purpose of this standard normal operation occurs when the installation is used
within its design parameters (as defined within EC Directive Annex 1, Note 2). Failures
(such as the breakdown of pump seals, flange gaskets or spillage caused by accidents) are
not normal operations.
Explosion protection
measures necessary
Further explosion
protection measures
*In Zones 20, 21 and 22, the possibility of deposited dust ignition shall also be taken into
account.
The Table applies to all types of ignition source.
mobile equipment that can be brought into the area. Records of this training and refresher
training shall be kept.
A.7.2.3 Maintenance
All maintenance work performed in a hazardous area shall be done under the control of a
work permit. In particular, the competence of personnel working on hazardous area
electrical equipment should be rigorously assessed. Where hazardous area electrical
equipment is to be isolated at a switch-panel in an unzoned area, multiple locking of switch-
panel isolators should be strongly considered. Each Permit To Work (PTW) signatory
should hold a key.
A.7.2.4 Inspection and checking
At a site where hazardous explosive atmospheres may occur, its overall explosion safety
shall be verified. Before it is used for the first time, and after any damage or alterations with
safety implications, its safety shall be verified.
The effectiveness of the explosion protection measures taken in a plant shall be checked at
regular intervals. The frequency of such checks depends on the type of measure. All
checks may be carried out by competent persons only. Examples of equipment to be
routinely checked for performance would be ventilation systems and gas detectors.
A.7.2.5 Marking of hazardous areas
Hazardous areas shall be marked with signs such as ‘no smoking’ or ‘naked lights’,
‘authorised staff only’, in addition to the necessary international signs for a hazardous zone.
Signs shall comply with any statutory requirements
The points of entry to hazardous areas shall be marked with the following warning sign:
Figure A.2 Warning sign for areas where explosive atmospheres may occur
This sign is required, e.g., for rooms or areas in which a hazardous explosive atmosphere
may arise (such as cylinder filling buildings or fenced enclosures where flammable liquids
are stored). If the hazardous area is not the whole space concerned, but only part of it, that
part may be marked by yellow/black diagonal stripes on the floor.
Other details may be added to the warning sign, indicating, e.g., the nature and when the
explosive atmosphere may exist. It may be desirable to place other warning signs for
example forbidding smoking, etc.
e) that the workplace and work equipment, including warning devices, are designed,
operated and maintained with due regard for safety;
f) that arrangements have been made for the safe use of work equipment.
The explosion protection document shall be drawn up prior to the commencement of work
and be revised when the workplace, work equipment or organisation of the work undergoes
significant changes, extensions or conversions.
The operating unit may combine existing risk assessments, documents or other equivalent
reports and incorporate them into the explosion protection document.
A.8.1 Implementation
Typical headings for an explosion protection document are shown in Table A.3.
Table A.3 Typical headings for an explosion protection document
AREA
ACTIVITY LOCATION Notes
CLASSIFICATION
1. Discharge of LPG
AREA
ACTIVITY LOCATION Notes
CLASSIFICATION
2. Loading of LPG
Depot
Temporary Zone 1: 0.5 m (1 ft 8 in)
Disconnection of loading hose or Terminal radius around coupling-to-coupling
hard arm following loading of an 1,8
Cylinder Filling Plant break point or bleed point for
LPG rail tanker.
release of inter-coupling product.
AREA
ACTIVITY LOCATION Notes
CLASSIFICATION
Customer storage of LPG cylinders
Commercial premises Non hazardous area 7
in open air
LPG cylinders in use in open air Commercial premises Non hazardous area 7
NOTES:
1. See Ref 1, Chapter 9.7.8.2.of ADR 2007. This reference requires a 0.5 m (1 ft 8 in) radius Zone 1 around venting
devices.
2. A release of LPG takes place when a pressurized hose is disconnected. Normal practice would be to release this
pressure via a bleed screw of no more than 1.5 mm (0.0591 in) diameter until atmospheric pressure is reached.
The pressure of release declines rapidly from operating pressure to atmospheric. The worst poss ble case would
be for the pressure to remain constant throughout the release, creating a jet of LPG. This jet has a dispersion
distance of 2.5 m (1 ft 8 in) when calculated according to Ref 6, “Calculations in Support of IP15: Area
Classification Code for Petroleum Installations” published by The Institute of Petroleum (now The Energy
Institute), London.
3. Pumps with mechanical seals that are wetted by the product pumped will have a minute leakage rate which is
ventilated very rapidly to below the lower flammable limit by the minimum air movement conditions experienced.
To be conservative in the estimation of hazardous area 0.5 m (1 ft 8 in) zone is allowed around the pump seal.
Pumps of a completely sealed design, normally using a magnetic coupling between motor and pump, will not
create a hazardous area.
4. When LPG cylinders are being filled, the release rate to atmosphere depends on the type of cylinder valve and
the type of filling head used to fill it. The volume released each time a fill head disconnects is quantifiable and the
frequency of disconnection is also defined. Calculating the dispersion to lower flammability limit of typical
releases produces distances from 0.5 m (1 ft 8 in) to 1.5 m (5 ft). As rectification of leaking cylinders and other
work involving cylinders may take place in a filling centre, the whole building is classified as Zone 2 because
occasional unplanned releases may take place at random locations.
5. When filling cylinders in open air, the liquid released when a filling head disconnects is the same as for indoor
operations and results in the same Zone 1 around the filling machines. The minor releases of vapour occurring
during other cylinder rectification operations do not give rise to a zone as they do not normally occur and are
rapidly diluted to the lower flammability limit by natural ventilation.
6. Prior to transporting empty LPG cylinders to a filling plant for filling, the driver checks them for leakage, as it is not
permissible to transport leaking cylinders. The empty cylinders will be stored at the filling plant prior to filling.
During the filling process and after filling, the cylinders are inspected and will not leave the filling centre if they are
leaking. In addition to having a closed valve, the cylinders are capped as a secondary seal. There is, therefore,
no situation in normal operations where a cylinder will release LPG to atmosphere.
7. Due to the wide variety of possible types of intermediate cylinder storage premises, it is not possible to say
categorically that they are all unzoned, as the length of storage, the state of the cylinders and the state of the
building cannot be predicted. A well-ventilated building within a well-run operation, with a good standard of
cylinder, and segregation of any dubious cylinders, would not normally have a flammable atmosphere present
and would not generate a hazardous zone.
8. Temporary hazardous areas, as defined in the following point 9, shall be marked and shall not have any
permanent equipment installed in the area that would create a source of ignition, i.e. for the installation of
equipment it is to be treated as a permanent zone. When the operation which creates the temporary zone is not
taking place, normal industrial equipment may enter the area. Procedures and controls shall be in place to ensure
that the temporary hazardous area is enforced during the operation requiring it. This includes marking and
signage for the area.
9. Temporary hazardous area - A hazardous area existing only while equipment is temporarily present and operated
to give the poss bility of the presence of an explosive atmosphere. As a consequence, temporary activity will lead
to a temporary hazardous area. For example, there would be a temporary hazardous area at an LPG road tanker
loading bay while the tanker ullage gauge is in use or the hose is being disconnected.
Descriptions
B – Driving unit for chain conveyor F – Roller conveyor for rejected cylinders
Figure B.5 Safety distances for cylinder filling and cylinder storage
A = 15 m (50 ft)
B = 10 m (33 ft)
C = 5 m (16.5 ft)
X + Y = 15 m (50 ft)
Figure B.9 Schematic for bulk road vehicle loading controls procedures
Figure B.10 Typical arrangement for loading/unloading an LPG rail tank wagon using
a compressor
* = Do not use
Nominal diameter
(mm)
15 20 25 32 40 50
Delivery rate Pressure drop
(litres/minute) (bar)
38 0.11 0 0 0 0 0
76 0.44 0.14 0.08 0 0 0
114 1.00 0.31 0.19 0.07 0 0
151 1.77 0.54 0.30 0.13 0 0
189 2.76 0.83 0.46 0.20 0.07 0
227 3.97 1.10 0.66 0.28 0.10 0
265 * 1.45 0.90 0.36 0.14 0.07
303 * 1.93 1.14 0.46 0.17 0.09
341 * 2.41 1.45 0.57 0.22 0.10
379 * 3.24 1.72 0.70 0.28 0.14
Nominal diameter
(mm)
15 20 25 32 40 50
Delivery rate Pressure drop
(litres/minute) (bar)
38 2.07 0.28 0.06 0.02 0.01 0
76 * 1.00 0.23 0.07 0.03 0.01
114 * 2.14 0.51 0.17 0.06 0.02
151 * 3.72 0.87 0.29 0.11 0.03
189 * * 1.31 0.44 0.17 0.04
227 * * 1.82 0.62 0.24 0.06
265 * * 2.44 0.82 0.32 0.08
303 * * 3.19 1.07 0.41 0.10
341 * * 3.90 1.31 0.51 0.12
379 * * 4.81 1.61 0.61 0.15
Nominal diameter
(mm)
20 32
Delivery Rate Pressure drop
(litres/minute) (bar)
38 0.17 0.02
76 0.70 0.08
114 1.55 0.17
151 2.76 0.30
189 4.31 0.48
227 * 0.69
265 * 0.94
303 * 1.23
341 * 1.53
379 * 1.92
Example:
Delivery rate: 227 litres/minute (60 gallons/minute)
Product: Commercial Propane
Ambient/product temperature: 21 °C (70 °F)
Receiving vessel: Filling into vapour space
No vapour return line used
Bulk road vehicle does a complete drop in one operation
Pressure drop through 50 mm (1.96 in) diameter meter 0.18 bar (0.018 MPa)
Pressure drop through 50 mm (1.96 in) diameter globe valve Negligible
Pressure drop through 32 mm (1.26 in) diameter globe valve 0.28 bar (0.028 MPa)
Pressure drop through 32 mm (1.26 in) diameter filler valve 0.69 bar (0.069 MPa)
Pressure drop through 15 m (0.59 in) of 32 mm diameter hose 0.62 bar (0.062 MPa)
Back-pressure build-up in tank being filled 1.17 bar (0.117 MPa)
Drop in pressure tank being discharged 2.75 bar (0.275 MPa)
TOTAL 5.69 bar (0.569 MPa)
The total differential pressure head varies considerably with product temperature because
of the significant effect of the pressure build-up in the vessel being filled and the pressure
drop in the vehicle's vessel, both of which are affected by the temperature of the product
(see Table C.1 and Table C.2).
For example, if the temperature was 38 °C (100 °F) instead of 21 °C (70 °F) the differential
pressure would rise to 9.21 (0.921 MPa) bar.
APPENDIX D TYPICAL RAIL HEAD DESIGN AND LAYOUT FOR RAIL TO ROAD LPG
TRANSFER
Figure D.1 LPG rail/road transfer facility - View from rail wagon side of fire wall