C ONCLUSIONES

5.2.1 General requirements

5.2.1.1 Above ground storage containers shall be located in the open air outside buildings.

5.2.1.2 Storage containers within a group shall be located so that their longitudinal axes are parallel to each other and preferably are directed away from any nearby storage of hazardous gases or flammable or combustible liquids. Subjected to the approval of the relevant authority, cylindrical storage containers may be placed end to end, provided that the distance between the ends is not less than 3 m or twice the diameter of the larger container, whichever is the greater.

5.2.1.3 Storage containers shall not be installed one above the other. An aboveground container shall not be directly above any underground container.

5.2.1.4 To avoid accumulation of liquid or vapour beneath or in the immediate vicinity of a container, the container shall not be situated in or vertically above a depression on the site, nor should the area under or around the container be filled with aggregate with a high percentage of voids.

No bunding around LPG containers is required but a diversion wall may be provided to control a spill.

5.2.2 Overhead transmission lines

The placing of storage containers within 1.5 m measured horizontally from the vertical plane of overhead transmission lines shall be avoided, unless a suitable overhead earthing screen is provided extending 1.5 m beyond the container plan area.

5.2.3 Gas storage other than LPG

The minimum separation between a LPG container and storage of a gas other than LPG shall be as shown in Table 5.

5.2.4 Flammable and combustible liquids storages

LPG containers shall not be located within the bunded areas of flammable and combustible liquids storages. Diversion kerbs, grading, compounds or the equivalent shall be provided to prevent the accumulation of flammable and combustible liquids under a LPG container.

Above ground storage containers shall be at least 2 m from the fill point of an underground container containing flammable or combustible liquid.

For Public Comment

Table 5. Minimum separation between an LPG container and a storage of gas other than LPG

Gas storage Minimum separation distance

(m) a) Liquid oxygen in containers or cylinders

i) up to 5 kl of LPG capacity

ii) over 5 kl up to 20 kl of LPG capacity iii) over 20 kl of LPG capacity

b) Compressed oxygen in cylinders c) Combustible gases other than LPG d) Other compressed gases in cylinders e) Gases other than LPG or oxygen, in

containers

10 15

refer to relevant authority 6

treat as being LPG 6

specific approval for each install

5.2.5 Ignition source

A storage container shall be located so that:

a) a fixed ignition source does not fall within a Zone 0, 1 or: 2 area; and

b) the horizontal distance from container valves, and filling and discharge connections to fixed ignition source is not less than 4.5 m.

5.2.6 Safety distances

5.2.6.1 General

Safety distances are intended to protect the LPG facilities from the radiation effects of fires involving other facilities as well as to minimise the risk of escaping LPG being ignited before being dispersed or diluted.

Safety distances shall be measured horizontally and radially from the container shells to the specified feature (e.g. an adjacent storage container, building, and property boundary) except that where deflection or radiation walls are used; the distance shall be measured in a horizontal line around such walls.

5.2.6.2 Use of deflection walls

Deflection walls (see 15.6.1) used to achieve safety distances shall comply with the following requirements:

a) a deflection wall shall not be lower than 2 m high and shall have a 4 h fire resistance rating (see note);

b) the deflection wall shall be located in accordance with the requirements of Annex F;

For Public Comment

c) not more than two separate deflection walls located on opposite sides of the LPG container shall be built. A continuous wall or two separate walls containing an acute angle shall not be built around LPG container; and

d) the deflection wall shall not be located on the property boundary, if the neighbouring or adjacent property may be built upon.

NOTES:

1. Deflection walls can pose a serious hindrance in fighting a fire if poorly positioned.

2. A wall constructed from brickwork, masonry or concrete, 200 mm thick or reinforced concrete 150 mm thick, is deemed to have a 4 h fire resistance rating.

5.2.6.3 Changed site conditions

Where alterations on the installation site result in a breach of the requirements for safety distances, the containers affected shall be moved so as to restore compliance or the container(s) shall be taken out of service.

5.2.6.4 Refineries and bulk plants

Location of aboveground storage containers in refineries and bulk plants shall comply with the minimum safety distances given in Figure 1.

5.2.6.5 Bulk storage at consumers' premises

This applies to commercial and industrial consumers' premises such as industrial plants and hotels where there is bulk storage of LPG. Location of aboveground storage containers in these premises shall comply with the minimum safety distances given in Figure 2.

The following requirements shall also apply:

a) The number of storage containers in any one group shall not exceed six. Any container in one group shall be at least 7.5 m from the nearest storage container in another group unless a deflection wall is erected between the groups. When deflection walls are used to separate groups of containers, the direct distance from each container in one group to the nearest container in another group shall be at least 4 m. This requirement does not apply to installations of cylinder systems.

b) Containers up to 0.5 kl water capacity may be permitted with zero distance to buildings, property boundaries, etc. provided the space in the opposite direction is clear for a minimum distance of 3 m. Not more than four containers shall be permitted to be installed in a group with zero distances. Such groups of containers shall be separated from other groups of containers by a minimum distance of 8 m given in Figure 3.

Maximum of two groups of containers are allowed for such purposes.

c) Vaporisers, other than direct-fired type, shall be installed at a minimum distance of 1.5 m from the nearest storage container. Direct-fired vaporisers shall be installed at the minimum safety distances given in Figure 2. Further requirements for vaporisers are given in 4.3.

For Public Comment

Min. safety distance (m)

Water capacity of individual

container (kl)

A B C D E F R S T U

< 135 135 to 265

> 265

(D1 + D2)/4 (D1 + D2)/4 (D1 + D₂)/4

30 45 60

3 3 3

6 6 6

5 5 5

10 10 10

see Figure 7

NOTE. The location of the deflection wall shall comply with the requirements shown in Annex F.

Figure 1. Location of aboveground containers in refineries and bulk plants

For Public Comment

Min. safety distance (m)

Water capacity of individual container

(kl) A B C D G H

Up to 0.5 Over 0.5 to 2.5 Over 2.5 to 10 Over 10 to 135

None 1 1 (D1 + D2)/4

None^a 4.5 7.5 15

3 3 3 3

6 6 6 6

10 10 10 10

see 4.3.3.3 d)

NOTES:

1. The location of the deflection wall shall comply with the requirements shown in Annex F.

2. For location of indirect-fired vaporiser, see 5.2.6.5 c) and 4.3.1.3 e), f).

a Subject to the requirements in 5.2.6.5 b).

Figure 2. Location of aboveground containers for bulk storage at consumers’

For Public Comment

Figure 3. Installation of containers up to 0.5 kl

5.2.6.6 Automotive LPG dispensing stations

This applies to location of aboveground storage containers in sites where LPG is dispensed into permanently mounted fuel containers of vehicles.

Location of aboveground storage containers in these premises shall comply with the minimum safety distances given in Figure 4.

For reasons of space and cost economy a so-called 'compact unit' (a unit where the storage container, compressor, pump and dispenser column are mounted on a steel frame) is permitted provided that the storage container does not exceed 8 kl water capacity. Such compact units do not have to meet the minimum safety distance between storage container and dispenser but have to comply with the other safety distances. The compact unit can be prefabricated and transported complete to the site. Further requirements for automotive LPG dispensing stations are given in Section 13.

The maximum number of storage containers in any one group and the safety distance between groups of containers shall comply with 5.2.6.5 a).

For Public Comment

Minimum safety distance

NOTE. The location of the deflection wall shall comply with the requirements shown in Annex F.

Figure 4. Location of aboveground containers in automotive LPG dispensing stations

For Public Comment

5.2.7 Vertical LPG storage containers in industrial consumers' premises

5.2.7.1 Vertical LPG storage containers more than 0.5 kl are allowed to be installed in industrial consumers' premises only. The capacity of each container shall not exceed 20 kl and must be so located to comply with the minimum safety distances given in Figure 2. The vertical LPG storage containers must be designed in accordance with the applicable provisions for horizontal ASME storage containers and shall be fabricated with lifting lugs or some other suitable means to facilitate erection in the field. Vertical containers designed for permanent installations in stationary service aboveground shall be installed on reinforced concrete or steel structural supports on reinforced concrete foundations which are designed to meet the following loading provisions:

a) 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 (earthquake) forces, and hydrostatic test loads.

b) Design pressure (see Table 1) 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.

c) Wind loading on containers shall be based on wind pressures on the projected area at various height zones aboveground in accordance with MS 1553. Wind speeds shall be based on a Mean Occurrence Interval of 50 years.

d) Seismic loading on containers shall be based on a seismic analysis of the proposed installation which meets the approval of the authority having jurisdiction.

5.2.7.2 Steel supports shall be protected against fire exposure with a material that has a fire resistance rating of at least 2 h.

5.2.7.3 Vertical ASME containers used in liquid service shall not be manifolded to horizontal ASME containers. Vertical ASME containers of different dimensions shall not be manifolded together.