DESIGN OF CONTAINERS FOR LPG

ASME Boiler and Pressure Vessel Code, Section VIII Division 1 or 2

Design of Pressure and Temperature

The design pressure of LPG containers must not be lower than the vapor pressure of the product.
stored at the maximum design temperature of the product, the resulting pressure of the pressure
partial of non-condensable gases in the vapor space and the hydrostatic head of the full product
it must be considered.

The relief valve requires a differential between the design pressure and the maximum vapor pressure.

VACUUM DESIGN

a) Design for a partial vacuum condition.- this alternative is used when the
vacuum conditions are given by the ambient temperature conditions Pd=minPv
@Tmin ambient in this situation does not require additional protection for the vacuum.
b) Partial vacuum design with a vacuum relief valve and connection to a supply
gas.- this alternative may compromise product quality.
c) Partial vacuum design with a relief valve that allows air to enter
container. This alternative under certain conditions may present a risk due to the
presence of air in the storage of LPG this risk must be considered in the
design.

CONSTRUCTION MATERIALS

ASME Boiler and Pressure Vessel Code.

Materials with a low melting point should not be used for LPG containers such as the
aluminum and brass.

CONNECTIONS OF CONTAINERS

The number of perforations in any container must be minimized particularly

those located below the working level of the liquid (below the vapor phase)

The flange connections must have a minimum of ASME Class 150. All connections
They must have a minimum NPS of ¾.

DIKING

5.5.1 If the dike around the vessel is to be used for spill containment,
The area of the dam will be designed according to the requirements indicated in 5.5.2 to 5.5.7.

5.5.2 The leveling of the area beneath and around the containers will direct any leaks of
liquid or spills towards the edge of the area with dikes. The rating must have a minimum of
Percentage of slope.
 Within the diked area, leveling should cause the spills to accumulate away.
of the vessel and any piping located within the area with docks.

5.5.3 If an LPG sphere has dikes, each sphere must have its own dike area.
If LPG is stored in horizontal containers, a single area with dikes can serve a
tank group, as defined in 5.1.3.3, that is, the horizontal LPG tanks with
capacities of 12,000 gallons or more will not be grouped in more than six tanks each
one. When multiple groups of horizontal LPG containers need to be provided, each
the group must be separated from adjacent groups by a minimum horizontal distance of
shell to shell of 50 feet.

5.1 SITE SELECTION:

The site selection aims to minimize potential risk to adjacent property.

presented by the storage installation and the risk presented to the installation of
storage due to a fire or explosion on the adjacent property. The following will be considered
following factors

in the site selection:

a) Proximity to populated areas

b) Proximity to public roads
c) Risk of adjacent facilities
d) Storage quantities
e) Current and predicted development of adjacent properties
f) Topography of the site including elevation and slope
g) Access for emergency response
h) Availability of necessary services
i) Requirements for the receipt and delivery of the products.
j) Local regulations
k) Prevailing wind conditions

Except for the spacing, the design characteristics discussed in this standard are
intended to prevent a significant incident. The spacing is meant to minimize both the
potential for small ignition leaks as the risk of exposure presented to containers,
adjacent equipment or facilities in case ignition occurs. The spacing does not have
the intention to provide protection against a major incident.

MINIMUM REQUIRED DISTANCES

Minimum horizontal distance between the frame of a pressurized LPG tank and the line of
adjacent property are:
The minimum horizontal distance between two LPG tanks or between an LPG tank and any other.
pressurized tank with explosion risk is:

a) Between two spheres, two vertical containers, or between a sphere and a vertical container,
5ft or half the diameter of the largest container.
b) Between two horizontal containers, or between a horizontal container and a sphere or a
vertical container, 5ft or ¾ of the diameter of the longer container.

The minimum horizontal distance between a LPG tank and a non-pressurized tank is
flammable must be:

a) If the other storage is refrigerated, ¾ of the largest diameter

b) If the other container is an atmospheric tank and is designed to hold a material
with a flash point of 100°F or lower, 1 diameter of the largest tank.
If the other container is in atmospheric tanks and is designed to hold a
material with a flash point of 100°F or higher, half the diameter of the largest tank

The minimum horizontal distance between the shields should not exceed 200ft.

The minimum horizontal distance between a LPG tank and a regularly occupied building is:

a) if the building is used for the control of storage facilities, 50ft.

b) If the building is used for purposes other than storage control,
100ft
c) In compliance with API 752, it can be used instead of the requirements of paragraphs a and b.

The minimum horizontal distance between a propane tank and other equipment:

a) for process containers, 50 ft

b) for teas or other equipment exposed to flames 100 ft.

c) for other equipment exposed to fire including process furnaces and service boilers, 50 ft

d) for rotary equipment, 50ft, except for the pumps that suck from the LPG tank
(10 ft)

e) for the aerial transmission lines of energy and electrical substations, 50 ft, in addition to the
the location must be such that a break in the overhead lines does not cause the exposed ends
do not fall on any container or equipment.

f) for loading and unloading of equipment such as trucks, wagons, 50 ft.

g) for waterways, docks, 100 ft

h) for stationary internal combustion engines, 50 ft

the minimum horizontal distance between the LPG tank and the edge of a containment area
drainage for fuel tank, 10ft

NOTE: if the containment is carried out using dikes or walls, the edge of the area of
Containment of the spill for spacing is defined as the centerline of the dike or wall, if it is
by leveling slope or channels, the edge of the spill containment area is defined as
the outer edge of the wet area in the design incident for the containment installation of
spillages.

LOCATION OF LPG TANKS AND EQUIPMENT

- LP gas pressurized tanks should not be located inside buildings, within areas
contingency for fuel storage, or within areas of
contingency for refrigerated tanks.
- The pumps and compressors that draw from the LPG tanks should not be located
within the contingency area of any facility, unless measures are taken
protection against potential exposure to fire e.g. (a direct coupling pump)
of the submerged motor, without a rotating element outside the containment vessel of the
pump, a submersible pump inside a LPG tank.
- Horizontal LPG tanks with capacities of 12000 gallons or more should not
to be in groups of more than six tanks each. Where there are groups of
horizontal LPG tanks the minimum horizontal distance from group to group must
to be 50 ft
- The LPG tanks must be oriented so that their longitudinal axes do not
pointing towards other facilities (containers, process equipment, rooms of
 control, loading or unloading facilities, storage facilities of
flammable or combustible liquids or installations outside the located facilities
in the vicinity of the horizontal container

FIRE PROTECTION

The design of the storage facility including the location of the plant tracks,
walkways, doors, operational equipment must be designed to allow personnel and equipment to
to reach any area affected by the fire quickly, the design must allow for at least two
access directions.

SYSTEM DESIGN

Fire water systems must be tested to verify that their performance is the
that was designed, since the capacity of the water network may gradually deteriorate as
result of the accumulation of scale in the water network, a Hazen–Williams coefficient will not be
more than 100 for uncoated steel tubes.

a fire protection water system must be provided in a loop around the portions of
storage and handling of a LPG facility.

Sufficient isolation valves must be provided in the network to prevent loss due to
to an interruption in the pipe. The shut-off valves must be arranged in such a way that
all parts of the plant can be protected with a part of the main water system against
fires when a damaged section is isolated for repair.
The water system capacity must be equal to the amount of water required for cooling the
largest tank to be protected, but the amount required to cool adjacent containers
, but the reserve capacity for up to three additional cooling streams of 250 GPM
when the capacity of the water system is determined by the requirement of the LPG tank,
it is allowed to section the system to reduce the maximum simultaneous water requirement against
fire.
the piping used for fire water supply lines and the branch lines to
the hydrants must have a size of at least 6 NPS (nominal pipe size). The lines of
derivatives for diluting, monitoring, or spraying systems are allowed to be smaller,
as long as the hydraulic calculations show that the selected size will provide the
design demand at the required pressure.

the fire water system must operate in all seasons and must be capable of
deliver 100% of the design flow for at least 4 hours, the fire protection system must be
frost protected if necessary.

the fire water network must be designed so that at least half of the water
required for the largest incident that can be delivered if a single section is lost
fire water pipe
Regardless of the method used for extinguishing the fire, the location of the
Hoses must be organized in such a way that each storage container can be reached.
at least two directions for at least three cooling streams, none of the
which uses more than 300 ft of hose.

The water system must be designed to provide water for cooling the equipment to be protected within.
activation de60segde to achieve the designed water delivery rates within 10 minutes
of the system activation.

the fire water system must be designed to facilitate testing to ensure

reliability, appropriate flow rate, and adequate coverage of the protected equipment.

FIRE WATER APPLICATION METHODS

LPG storage containers must be protected by deluge water systems.

fixed monitors, spray water systems, or some combination of these systems. the equipment
portable will be used but will not be used as a primary control method.

DILUENT WATER SYSTEM

It is a system in which all the water is applied from the top of the container and allows it to flow.
on the sides.

the system must be designed so that under non-fire conditions the water flows
uniformly over the entire surface, the adequacy of the water coverage will be determined
through performance tests.

The pipe used for the main water distribution lines must have a diameter of
at least 3 inches

The water distribution nozzles mounted on the top must have at least 1 ½
in size and must be equipped with proper deflectors to achieve good
water distribution.

The system must be operated manually from a safe location that is outside the area
contingency which is at least 50ft from the tank to protect. The location of the actuator of
the valve must be predominantly marked.

in locations with unattended or partially crowded operations, measures must be in place

It counts additional system activation methods, such as automatic operation. When you
an opera with an automatic or remote system should also provide a valve for
manual derivation in a safe and accessible place.

FIXED MONITORS

the entire surface of the containers must be reached by the current from the monitors
Each monitor must be accessible during the presence of fire or must be remotely activated.
and controlled.

The nozzles of the monitors must be adjustable for mist or direct flow as required.
to provide the most effective coverage to protect the container.

In cold climates, they must be protected against freezing.

-5.3.3 API 2510a minimum pressure of 100 psi

APPLIED WATER FLOWS FOR FIREFIGHTING

it depends on the method of application.

the surface area of the container that could be exposed to fire shall be the area of the
container above the level of the liquid contents at the lowest operational level of the container.

-For deluge or water spray systems, 0.1 GPM/ft2 of exposed surface area of the container.
there is concern or risk that a container may catch fire due to a flame or contact with
a substantial flow must provide a current of 0.25 gpm/ft2

FIRE DETECTION SYSTEMS

A security analysis must be used to determine the need for detection systems.
of fire and hydrocarbons.