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CLOSE THIS BOOKStructures Suitable for Emergency Storage in Tropical Countries (NRI)
Appendices
VIEW THE DOCUMENTAppendix 1: Letter to relief workers
VIEW THE DOCUMENTAppendix 2: Questionnaire for firms
VIEW THE DOCUMENTAppendix 3: Letter to firms
VIEW THE DOCUMENTAppendix 4: Main features of Botswana relief stores
VIEW THE DOCUMENTAppendix 5: Pyramid-shaped cap storage specification
VIEW THE DOCUMENTAppendix 6: Examples of emergency storage systems
VIEW THE DOCUMENTAppendix 7: Sub-categories of emergency stores
VIEW THE DOCUMENTAppendix 8: A note on steel frame warehouse design for emergency
VIEW THE DOCUMENTAppendix 9: Derivation of table 4 data
VIEW THE DOCUMENTAppendix 10: Derivation of annual costs
VIEW THE DOCUMENTAppendix 11: Store capacity for bagged produce

Structures Suitable for Emergency Storage in Tropical Countries (NRI)

Appendices

Appendix 1: Letter to relief workers

Dear

EMERGENCY FOOD STORAGE METHODS

suggested that I write to you because you have special experience of emergency operations. I am writing some guidelines for donors on emergency storage structures which include tarpaulins, prefabricated warehouses, etc. and I should be grateful for your help which I will, of course, acknowledge on behalf of this Institute. I am particularly keen to know about any emergency storage structure/method/operation that was unsatisfactory and for what reasons. For example, the structures may not have functioned adequately or were late arriving. By the same token I should like to hear about emergency storage structure/methods/operations that went well and, if possible, the reasons for this success. This of course will depend on the scale of the emergency and at which level of operation. Above all, I should like your comment on what you think is most important about the emergency storage structures you have encountered. I realize how busy you must be, but if you can find time to pass on your professional experience, this will be very valuable for others who find themselves confronted within an emergency storage situation.

Yours sincerely,

Appendix 2: Questionnaire for firms

1 Have your structures been sold overseas for emergencies?
2 Cost ex-works?
3 Any typical freight charges?
4 Do you send a supervisor? Cost?
5 Sizes of buildings available?
6 Delivery against firm order?
7 Estimated erection time with supervisor?
8 Number of people needed for erection?
9 Details of strips or foundations needed
10 Details of equipment needed
11 Ventilation
12 Experience overseas?

Appendix 3: Letter to firms

Dear
ODA GUIDE TO EMERGENCY STORAGE IN THE TROPICS

Thank you for providing us with information; I enclose a fact-finder sheet for your firm's emergency storage product.

I should be most grateful if you could telephone or write to me if there are any mistakes or omissions. This will ensure that your product is correctly described and meets the deadline for our 'Guide to Emergency Storage'.

We want to keep this format with a maximum of one A4 fact-finder sheet for each company to be as fair to everyone as possible.

Again, many thanks for your co-operation.

Yours sincerely

Appendix 4: Main features of Botswana relief stores

Outline specifications. Store function was:

(a) to keep relief food dry, cool, clean, pest free and secure;
(b) to keep capital and maintenance costs low;
(c) to enable rapid erection and completion of the food stores;
(d) to ensure rapid and easy movement of relief food in and out of the stores.

To achieve the objectives, the buildings and site were treated as an integral unit with major design features described in Table A below.


Table A: Main design features for relief food stores

Appendix 5: Pyramid-shaped cap storage specification

Site selection

Site with good access should be on high ground for natural drainage. Firm sub-soil with bearing pressure 100kN/m² or 16 pounds force per square inch. Avoid areas prone to cyclones, flooding or high winds.

Plinth

Construction raised to 0.3 m above ground, measuring 9.6 x 6.1 m. Build in batteries with short side facing prevailing wind to minimize wind damage to covers Dig trench around plinth perimeter; construct brick wall in this with concrete foundations to a height of 0.6 m; remove top soil and fill inner space with sand, compact to wall level and top with bricks. Site 36 hooks evenly in concrete blocks around plinth to provide purchase for lashing. The hooks are 20 mm, mild steel, 76 mm from ground. Construct a brick apron 0.6 m wide around the plinth, pointed with concrete.

Dunnage

Use wooden pallet or poles; bamboo mats are placed between the bags and the dunnage to prevent spilling of grain onto the plinth which helps reduce losses.

Covers

Black, low-density polyethylene 250 microns thick, shaped to suit the stack specified below. Separate cover tops provide additional protection. These are composed of high density polyethylene (HDPE) 125 microns thick with 36 eyelets each reinforced with a 50 mm diameter disc of 250 micron thick HDPE on both sides. Nets of HDPE rope 2 mm in diameter, colour black and UV-stabilized, are provided for sites with high winds. Net mesh is 450 x 450 mm. Net size is 10.35 x 7.2 m.

Ropes and lashings
Use 6 mm HDPE ropes or similar for tying stacks. Lash four times on long side, three times on short side. To prevent damage to covers, place gunny sack pads under ropes at stress points between cover and ropes.

Insulation

To prevent moisture migration, place a layer of paddy husk bags on top of the stack. A similar layer on the bottom of the stack will give additional protection.

Stacking

Clean plinths before laying out first wooden pallets and then woven mats, ensuring nothing juts out from the plinth. Stack bags cries-cross-wise for stability and ensure mouths of bags face inward. To ensure proper drainage, shape the top of the stack into a pyramid (after the 13th bag); one pattern is as follows:

Alternate layers of 10 bags lengthwise x 11 bags breadthwise, then 7 lengthwise, 16 breadthwise, into 12 layers,

i.e.

6 x110 = 660


6 x 112 = 672


1332

From the 13th layer the following pattern is adopted:

13th layer 9 x 11

=

99

14th layer 14 x 7

=

98

15th layer 8 x 11

=

88

16th layer 11 x 7

=

77

17th layer 6 x 11

=

66

18th layer 8 x 7

=

56

19th layer 3 x 11

=

33

20th layer 3 x 7

=

21



508

Thus with a total of 1850 bags x 80 kg each plinth carries about 150 tonnes.

Management

At receipt, sample and analyse before accepting only sound stocks to the plinth. Wheat and paddy are acceptable; do not accept milled products. Stocks in sound or new B-twill gunnies only are acceptable. Non-standard, loose bags or brimful bags are not suitable. Maximum moisture content 14%. Bag mouths should have 12-14 stitches.

Aeration is provided by raising the covers with the minimum labour. Aerate at least one per week in dry season. In rainy season on a clear day raise the covers to the 7-8th layer without removing lashings so that covers can be replaced quickly if sudden rain threatens. This partial aeration is insufficient because it leaves the top of the plinth untouched. Therefore, aerate fully on a sunny day. Sample fortnightly for pest and quality control. During aeration the mats and aprons should be swept clean and any spillage collected. Pest control will be necessary for prolonged storage.

Security is difficult to enforce with CAP storage. Fencing is a minimum requirement and floodlighting is a necessary addition. Of course, 24-hour watchmen are essential.

Salvage if stock does get wet, by destacking and separating the damaged bags. Remove grain cakes and lumps and re-bag. Re-stack after sundrying.

Note: CAP storage is very vulnerable to wind damage. The covers are easily damaged and so rain can damage stock. The system should only be used for emergency storage when dynamic management is available.

Appendix 6: Examples of emergency storage systems


Emergency storage systems

Appendix 7: Sub-categories of emergency stores

Symbol Description where necessary

A1

Conventional frame warehouse with steel portal or lattice frame. Metal roof cladding; metal, r.c. or other wall cladding. Concrete floor. Drive-through design requires large doors in opposite walls and reinforced floor to withstand loaded lorries. A permanent building.

A2

As A1 but with retaining walls for bulk grain. Aeration facility may be built in. A permanent building.

A3

A category including a variety of warehouses generally similar to A1, but unconventional in detailed design, therefore erected differently. Designs with prefabricated wall sections incorporating load-bearing members and steel claddings are quick to erect but more bulky for transport. Designs with structural members made up on site from components are slow to erect but economical to ship.

A4

A warehouse as type A1 but with design optimized for easy shipment and erection.

AS

Prefabricated steel building which folds for transport and is very rapidly erected using a crane. Size limited by the need to transport the complete folded building on one vehicle.

A6

Nissen-type steel-framed steel-clad building of semi-circular cross section. Doors normally in the ends.

A7

Traditional buildings of wood pole, earth brick and thatch, or other local materials.

B1

Industrial building system of load-bearing prefabricated flat panel sections for walls and roof.

B2

Low-technology building system employing wood and cork panels and plywood components, for small buildings only (under development).

B3

Frameless steel buildings constructed from prestressed shaped steel panels to give a mansard-shaped structure.

B4

Bulk silos of corrugated steel; must be provided with handling plant and normally also aeration facilities.

C1

Flexible-clad warehouses with a frame of steel or aluminium and clad with PVC-coated synthetic fabric. Drive-through design may be possible with some types.

C2

Flexible-clad structure, locally built with wood frame clad with plastic sheet.

C3

Traditional grain store, wooden framework with woven matting covering for roof and walls.

C4

Flexible silos for bulk or bagged grain, with plastic film, plastic coated fabric or rubber container and roof, and walls supported by welded steel mesh.

C5

Air-supported structure-flexible building supported by inflated double-wall sections. Requires a fan only for inflation. No increase in air pressure in storage space.

D1

Marquee tents, canvas with main supporting poles and subsidiary poles around vertical walls; ropes and ground anchors keep the tent erected.

D2

Cover and plinth system; outdoor stack on raised plinth with shaped plastic sheet cover. See Appendix 5.

D3

Outdoor stack covered with flat sheet tarpaulins of waterproof natural or synthetic fabric or tough plastic. Sheets preferably provided with reinforced eyelets and ropes to assist fixing.

D4

Air warehouse supported by increased air pressure inside building, provided by continuously running fan. Requires air-lock doors to enable the slightly elevated pressure to be maintained during loading.

Appendix 8: A note on steel frame warehouse design for emergency

The following factors contributed to design (Reid, 1987):

1 Having observed feeding stations, refugee camps, rehabilitation schemes and even re-housing schemes in many unfortunate parts of the world, we became convinced of a need for a cheap yet efficient standardised steel structure.

2 The following factors influenced the design:

(i) The cost of the basic element should be very low (the target price was £10/m² though this has now crept up slightly - see paragraphs 6 and 7).
(ii) All the items should be containerable, with several structures in one 20 ft container.
(iii) Each element should be manhandleable and portable, and thus should be able to get into difficult spots.
(iv) No power tools and plant or equipment should be needed.
(v) The building should be quick to erect, using unskilled labour with minimum supervision.
(vi) The building should be relocatable.
(vii) The building should be durable to full permanent standards.
(viii) The building should be able to evolve from simple overhead cover to enclose store to high standard lined and insulated buildings for use as hospitals or schools or community centres.
(ix) The building should be able to sit on flat soil, or existing concrete, tarmac or concrete pads or almost anything
(x) The finish inside and out of the rafters and cladding rails and purlins should be flush to make lining, insulating, etc. very simple.

3 The structure decided upon was a steel portal-framed building 2.5 m to eaves and 11m wide, and usually 29.5 m long in 5 bays of 5.9 m.

4 It is nominally designed for 40 kg/m² of snow or imposed load or 60 kg/ m² of wind (equal to a 50 year gust of perhaps 168 km/hour (47 m/s)).

5 The most cost-effective and economical cladding is Aluzinc coated profiled steel. It has a life expectancy of about 3 times that of galvanized steel and has better reflective/emissive properties.

6 The basic structure consists of 6 frames, 10 purling, the roof sheeting and ridge capping and all fixings and necessary bracings. It is easy to pack 4 such structures into a 20 ft container and sometimes possible to carefully fit in 5 buildings. The price for 4 roofed buildings ex-works loaded into a container is £15,320. Each shelter weighs about 4.2 t.

7 The same building but clad on the walls and incorporating sliding doors 2 x 2 m in the ends costs a bit more. Three can be fitted into a 20 ft container for a price of £18,940. Each enclosed store weighs about 6.5 t.

8 Every normal option of sheeting could be more available. For example in arid and sunny regions (such as the Sahel) the roof sheeting should be white polyester enamel-coated steel, at a modest extra price. Near humid sea shores, white-coated aluminium or white PVF2-coated steel may be a better choice. If buildings are to be air-lifted, or transported by helicopter then mill finish aluminium may prove the overall cost-effective solution. Drawbacks of different sheeting options include increased prices, minimum quantities (usually equivalent to about 6 units) and sometimes delayed deliveries.

9 Every option of window and ventilation and door is available. The drawbacks are increased costs and delays. Small quantities of exotic items cost more out of all proportion. A common requirement which is simple, is to have a band of translucent sheeting 0.3 m deep under both eaves. This only costs £120 extra per unit and gives a good internal light.

10 The lining of the walls can be done simply with a wide variety of materials, from local blankets to anodised aluminium panels. The list is too long to elaborate but a cost effective option is white enamelled galvanized steel liner plus 50 mm of fibreglass which costs £1,950 for each simple shelter or £2,750 for each enclosed shelter, giving a really nice clean looking interior and reasonable insulation.

11 The building can be staked to the ground with steel pins; bolted onto existing slabs; bolted onto purpose-made slabs or footings or staked first and slabbed later (which does make relocatability more difficult). A typical simple shelter should be erected in a few days although the record with an experienced crew of three men is 2« days.

12 Tools are only two spanners, one drill, one speed brace and one pop rivetter. Such a tool kit costs £27 and should serve to erect many shelters, but three spare drill hits (value £3) are needed for each new shelter.

Appendix 9: Derivation of table 4 data

Sources of data

Manufacturer's ex-works or f.o.b. prices for structures - see Part II. No provision is made for discounts.

Prices for containers, sea/air freight, rail and road charges in Sudan from Dacair Transport Ltd.

Erection costs include all expenses for supervisor (Part II), but no allowance for local labour because this regarded as a site cost.

Costs for foundations and floors are from Spon's, 1987.

Notes:

Building height are to eaves except where stated.

Dunnage is assumed to be locally procured (Morton, 1987) and a cost is estimated here; this is not included in the capital cost used in Appendix 10 because, with a 4-year life, this becomes an operating cost. Similarly, no charge is made for maintenance. The omission of these costs may or may not affect all stores equally, but is covered by the 15% contingency charge.

Sea freight rates are quoted in US$ and an exchange rate of $1 = £0.71643 has been used.

The cost of handling freight containers in port Sudan is unobtainable; the estimate used, $400, is above typical United Kingdom rates.

The most important assumption (Walker, 1986) is to have a stacking height of 2.0 m only; this is also discussed in the text. However, higher stacking and one single stack in each store have been included, to represent the pressure on storage that occurs on most sites from time to time.

A4 Steel portal-frame warehouse

2.5 m high x 11 m wide x 29.5 m long



Capacity: 2 stacks 2 x 3.5 x 27.5 m = 385 m³ = 257 t maize



1 stack 2.5 x 9 x 27.5 m = 619 m³ = 413 t maize



1 Capital costs

£


3 warehouses complete, packed in 1 container, f.o.b.

18,940


Container, 20 ft. non-returnable

750


Sea freight, United Kingdom to Port Sudan $1750

1,268


Rail freight, Port Sudan to Khartoum $1000 +

$400

1,014

Erection supervisor:



30 days @ £100/day + expenses

7,200


Concrete foundations and 150 mm (6") floor



3 x 324.5 m² @ £20/m²

19,470


Dunnage, local



3 x 324.5 m² @ £2/m² nominal

1,947


Total

50,598


Contingencies 15% 7,588



Grand total

£58,177


Capital cost for each warehouse

19,392


Capital cost per tonne stored @ 257 t capacity

75.5


Capital cost per tonne stored @ 413 t capacity

47.0


Capital cost for Table 4 and Appendix 10 excludes dunnage, i.e. £1 9,392 - 1/3 (1 947 x 1.1 5) = £1 8,646.

2 Procurement period

Days

Delivery from receipt of firm order to f.o.b.

28

Waiting for ship, maximum

14

Voyage to Port Sudan

21

Clearance from Port Sudan in emergency sitution

28

Transport (road or rail) to Khartoum, say

14

Transport, Khartoum to site, 6.5 t load (1 warehouse), say

10

Total

115

B3 Steel frameless prefabricated store

3.1 m high x 9.3 m wide x 23.4 m long

Capacity:

1 stack 2 x 6.3 x 21.4 m = 270 m³ = 180 t maize


1 stack 2.5 x 7.3 x 22.4 m = 409 m³ = 273 t maize

1 Capital costs


£


4 modular stores complete, packed in one container, f.o.b.

24,272


Container, 20 ft. non-returnable

50


Sea freight, United Kingdom to Port Sudan $1750

1,268


Rail freight, Port Sudan to Khartoum $1000 +

$400

1,014

Erection supervisor:



2 weeks @ £600/wk + expenses

3,800


Concrete foundations and 100 mm (4'') floor



4 x 217.6 m² @ £10/m²

8,705


Dunnage, local



4 x 217.6 m² @ £2/m² nominal

1,741


Total

£41,550


Contingencies 15%

6,232


Grand total

£47,782


Capital cost for each warehouse

11,946


Capital cost per tonne stored @ 180 t capacity

66.4


Capital cost per tonne stored @ 273 t capacity

43.8


Capital cost for Table 4 and Appendix 13 excludes dunnage, i.e. £11,946 = 1/4 (1741 x 1.15) = £11,445.

2 Procurement period


Days

Delivery from receipt of firm order to f.o.b.

14

Waiting for ship, maximum

14

Voyage to Port Sudan

21

Clearance from Port Sudan in emergency situation

28

Transport (road or rail) to Khartoum, say

14

Transport, Khartoum to site, 4.46 t load (1 warehouse), say

10

Total

101

C1 Steel frame plastic-clad store

3.3 m high x 12 m wide x 24 m long

Capacity:

2 stacks 2 x 4 x 22 m = 352 m³ = 235 t maize


1 stack 2.5 x 10 x 23 m = 575 m³ = 383 t maize

1 Capital costs

£

4 steel/plastic stores complete, packed in one container

36,320

Container, 20 ft. non-returnable

750

Sea freight, United Kingdom to Port Sudan $1750

1,268

Rail freight, Port Sudan to Khartoum $1000 +$400

1,014

Erection supervisor:


4 days @ £120/day + expenses

2,080

Floor cover sheet: 4 x 288 m² @ £2/m²

2,304

Dunnage, local: 4 x 288 m² @ £2/m²

2,304

Total

£46,040

Contingencies 15%

6,906

Grand total

£ 52,946

Capital cost for each store

13,236

Capital cost per tonne stored @ 235 t capacity

56.3

Capital cost per tonne stored @ 383 t capacity

34.6

Capital cost for Table 4 and Appendix 10 excludes dunnage, i.e. £13,236- 1/4 (2304 x 1.15) = £12,573.

Alternatively:

1 steel/plastic store, complete, packed for export

9,080

Air freight, United Kingdom to Khartoum,


4440 kg @ £1.50/kg

6,660

Erection supervisor, 3 days @ £120/day+ expenses

1,860

Floor cover sheet: 288 m² @ £2/m²

576

Dunnage, local: 288 m, @ £2/m²

576

Total

£18,752

Contingencies 15%

2,813

Grand total

£21,565

Capital cost per tonne stored @ 235 t capacity

91.8

Capital cost per tonne stored @ 383 t capacity

56.3

2 Procurement period


Sea (days)

Air (days)

Delivery from receipt of firm order to f.o.b.

7

7

Waiting for ship, maximum

14

-

Voyage to Port Sudan

21

-

Air transport, United Kingdom to



Khartoum

-

7

Clearance, Khartoum airport

-

3

Clearance from Port Sudan

28

-

Transport, Port Sudan to Khartoum, say

14

-

Transport, Khartoum to site, 4.4 t load, say

10

10

Total:

94

27

D1 Marquee tent

1.8 m high x 6 m wide x 19 m long


Capacity:

2 stacks 2 x 4 x 7.5 m = 120 m³ = 80 t maize


1 stack 2.5 x 5 x 18 m = 225 m³ = 150 t maize

1 Capital costs


£

£


New

Secondhand

1 tent complete with poles, pegs, etc.

2,800

1,050

Air freight, consolidated, 450 kg @ £1.50

675

675

Erection, local supervision, nominal

50

50

Floor cover sheet, 114 m² @ £2/m²

288

288

Dunnage, local: 114 m @ £2/m²

288

288

Total

3,981

2,231

Contingencies 15%

597

335

Capital cost per tent

4,578

2,566

Capital cost per tonne @ 80 t capacity

57.2

32.1

Capital cost per tonne @ 150 t capacity

30.5

17.1

Capital cost for Table 4 and Appendix 10 exclude dunnage,

i.e. New £4578 - (228 x 1.15) = £4,316
Secondhand £2,566 - (288 x 1.15) = £2,304.

2 Procurement Period Days

Delivery from receipt of firm order to f.o.b.

7

Air transport, United Kingdom to Khartoum

7

Clearance, Khartoum airport

3

Transport, Khartoum to site, 0.5 t, say

20

D3 Tarpaulin cover

Set of 3 tarpaulins 6 m x 10 m finished dimensions

Stack: preferred 4 x 8 m base, 2 m peak height = 48 m² = 32 t maize
alternative 5 x 9 m base, 2.5 m peak height = 76.5 m³ = 51 t maize

1 Capital costs


£

3 tarpaulins complete with eyelets and ropes


180 m² @ £0.79/m²

142

Net, polypropylene, 8 x 13 m

19

Air freight, 42 kg @ £1.50/kg (consolidated rate)

63

Erection, local supervision, nominal

25

Dunnage, local: 4 x 8 m stack, 32 m² @ £2/m²

64

Total

313

Contingencies 15%

47

Capital cost per stack

360

Capital cost per tonne @ 32 t per stack

11.2

Capital cost per tonne @ 51 t per stack

7.6_

Capital cost for Table 4 and Appendix 10 excludes dunnage, i.e. £360-(64 x 1.15) = £286.

2 Procurement Period

Days

Delivery from receipt of firm order to f.o.b.

5

Air transport, United Kingdom to Khartoum

5

Clearance, Khartoum airport

3

Transport, Khartoum to site, 42 kg

1


14

Appendix 10: Derivation of annual costs

A Dunnage and maintenance are regarded as local operating costs and are excluded.
B No residual values are allowed, although these can be calculated from Table 4 for relocatable stores from annual costs and use of tables.

C A useful life of 25 years for portal frame warehouses (normal practice)


13 years for frameless modular structure (Timpson,1987)


6 years for plastic-clad warehouse (Timpson, 1987)


4 years for canvas army tents (estimated)


2 years for length of 'average' emergency (FAO, 1986)


0.5 years for life of reinforced polythene tarpaulin (Reece, 1 987)

D A rate of interest of 10%

E An annual throughput of six weeks or nine times a year with 2 m stacking and store capacities given in Table 3.


Annual costs

Appendix 11: Store capacity for bagged produce


Stacking condition

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