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,
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?
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
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
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.
Emergency storage
systems
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. |
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.
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 |
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
Stacking
condition