LPG Storage Tank & Containers Standard Requirements

Containers shall be designed, fabricated, tested and marked (or stamped) in accordance with the Regulations of the U.S. Department of Transportation (DOT), the “Rules for the Construction of unfired Pressure Vessels”, Section VIII, Division 1, ASME Boiler and Pressure Vessel Code, or the API-ASME Code for unfired Pressure Vessels for Petroleum Liquids and Gases applicable at the date of manufacture.

Fuel or LPG Storage tanks & Containers showing serious denting, bulging, gouging or excessive corrosion shall be removed from service.

Repair or alteration of LPG or fuel containers shall comply with the Regulations, Rules or Code under which the container was fabricated. Other welding is permitted only on saddle plates, lugs or brackets attached to the container by the container manufacturer.

Heating or cooling coils shall not be installed inside storage containers.

Containers shall be painted either with yellow color using a paint made with a medium yellow chrome pigment or white color with a titanium oxide pigment.

Container Design or Service Pressure

a) The minimum design, or service, pressure of DOT specification containers shall be in accordance with the appropriate DOT regulations.

b) The minimum design pressure for ASME containers shall be in accordance with below Table.

c) Containers shall be designed to be self-supporting without the use of guy wires and shall satisfy proper design criteria taking into account wind, seismic (earth-quake) forces, and hydrostatic test loads.

d) Design pressure (see below Table) shall be interpreted as the pressure at the top head with allowance made for increased pressure on lower shell sections and bottom head due to the static pressure of the product.

e) Wind loading on containers shall be based on wind pressures on the projected area at various height zones above ground in accordance with Design Loads for Buildings and other structures, ANSI A58.1. Wind speeds shall be based on a Mean Occurrence Interval of 100 years.

Container Openings

a) Containers shall be equipped with openings suitable for the service in which the container is to be used. Such openings may be either in the container proper or in the manhole cover, or part in one and part in the other.

b) Connections for pressure relief valves shall be located and installed in such a way as to have direct communication with the vapor space, whether the container is in storage or in use. If located in a well inside the container with piping to the vapor space, the design of the well and piping shall permit sufficient pressure relief valve relieving capacity. If located in a protecting enclosure, design shall be such as to permit this enclosure to be protected against corrosion and to permit inspection.

c) Containers shall be fabricated so that they can be equipped with a fixed liquid level gauge(s) capable of indicating the maximum permitted filling level(s).

Container Markings

a) Containers shall be marked as provided in the Regulations, Rules or Code under which they are fabricated and in accordance with (b) and (c) below.

b) When LP Gas and one or more other compressed gases are to be stored or used in the same area, the containers shall be marked “Flammable” and either “LP-Gas,” “Propane” or “Butane.”

c) ASME containers shall be marked as noted here under. The markings specified shall be on a metal nameplate attached to the container, so located as to remain visible after the container is installed. The nameplate shall be attached in such a way that corrosion of the nameplate or the container will be minimized:

i) Service for which the container is designed; i.e. underground, above ground, or both.
ii) Name and address of container supplier or trade name of container.
iii) Water capacity of container in lb or U.S. Gallons.
iv) Design pressure in psig.
v) The wording “This container shall not contain a product having a vapor pressure in excess of- psig at 100 deg.F”.
vi) Tare weight of container fitted for service for containers to be filled by weight.
vii) Outside surface area in sq. ft.
viii) Year of manufacture.
ix) Shell thickness Head thickness
x) OL – OD – HD
xi) Manufacturer’s Serial Number.
xii) ASME Code Symbol.