 KENYA STANDARD       DKS 2985 :2023  
ICS 67.060  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Silos for storage of unbagged cereals and 
pulses - Requirements  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    © KEBS 2023  First  Edition 2023  
 
  DKS 2 985:2023  
ii  KEBS 2 023— All rights reserved   
TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Ministry of  Public Health and Sanitation  
Government Chemist's Department  
Kenya Institute of Food Science and Technology  
Agriculture and Food Authority  
Warehousing Receipt Council  
Capwell Industries  
Kenya Association of Manufacturers  
Kenya Livestock and Agricultural Research Organization  
Kenya Institute if Research and Development  
National Cereals and Produce Board  
Unga Ltd.  
East African Grain Council  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in in dustry, Kenya Standards shall be regularly reviewed.  Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 2023  
 
Copyright. Users are reminded t hat by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001  of the Laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bure au of 
Standards may be reproduc ed, stored in a retrieval system in any form or transmitted by any means without prior permission in writing 
from the Managing Director . 
 KENYA STANDARD                                          DKS 2985:2023  
 
                                                                                                                              ICS 67.060  
KEBS 2023 — All rights reserved    iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Silos for storage of unbagged cereals and 
pulses - Requirements  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF ST ANDARDS (KEBS)  
 
Head Office: P.O. Box 54974, Nairobi -00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org, Web:http://www.kebs.org  
 
Coast Region     Lake Region    Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 29 49, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 DKS 2 985:2023  
iv  KEBS 2 023— All rights reserved   
 
Foreword  
 
This Kenya Standard was prepared and re vised by the Cereals and Pulses Technical Committee under the 
guidance of the Standards Projects Committee, and it is in accordance with the procedures of the Kenya 
Bureau of Standards.  
 
Silos are intended for the storage and physical protection of grains from the weather, prevention of the entry 
of pests and security. They also include materials and equipment required for inspection, drying, screening, 
sorting, grading, packaging and handling of grain  and storage pest control.  
 
The structure should be prop erly built to provide good storage conditions, easy access and safe working 
conditions, and should not provide harbourage for pests.  
 
In general, the condition of grain changes slowly while in storage; the extent of any change depends on 
ambient conditions  at harvest. Changes in moisture content and temperature are limited to the periphery of a   
bulk, unless the storage period is prolonged or the grain is ventilated.  
 
Heavy infestations of insects, however, may cause a rise  in temperature  and  in the grain mass, possibly due 
to the development of fungi. Ideally, the silos should permit some control of temperature and humidity, to 
keep the grain cool, dry and at a uniform temperature as much as possible.  
 
The objective of this sta ndard is to provide guidance to industry regarding appropriate storage of cereals and 
pulses in order to reduce on the level of post -harvest losses incurred in these commodities.  
 
This standard as well will be invaluable in promoting the Structured Tradin g Systems (STS) in the region to 
promote both regional and International trade in cereals and pulses.  
 
During the preparation of this standard, reference was made to the following documents  
 
ISO 6322 -1:1981, Storage of cereals and pulse — General consider ation in keeping cereals.  
 
ISO 6322 -2:2000, Storage of cereals and pulse — Practical recommendations.  
  
KS 2657:2022 Warehouse and warehousing of bagged cereals and pulses - Requirements  
 
Acknowledgement is hereby made for the assistance derived from these sources.  
 
  
KENYA STANDARD      DKS 2985:2023  
 
 
KEBS 2016 — All rights reserved    1  
 
 Silos for storage of unbagged cereals and pulses - Requirements  
 
1 Scope  
 
This draft Kenya Standard covers  the location, structural, facility, safety and management requirements for   
silos for  storing bulk unbagged cereals and pulses.  
 
This standard applies to public silos, private co mmercial silos, bonded storage and cooperative silos .  
 
2 Normative references  
 
The following referenced documents are indispensable for the application of this document. For dated 
reference s, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
 
ISO 6322 -3, Storage of cereals and pulses — Control of attack by vertebrate and invertebrate animals  
 
 
3 Terms and  definitions  
 
For the purpose of this standard, the following terms and definitions shall apply.  
 
3.1 
Silos  
a large, round tower for  storing grains  
 
 
3.2 
competent authority  
any person or organization that has the legally delegated or invested authority, c apacity, or power to perform 
a designated function  
 
 
3.3 
 defective grains  
 grains which are mouldy, pest damaged, discolored, stained, rotten and diseased, immature and shriveled 
grains and broken grain  
 
3.4 
 foreign matter  
all organic and inorganic mate rial 
 
 
3.5 organic matter                                                                                                    DKS 2985:2023  
 
2  KEBS 2 023— All rights reserved  any animal or plant matter (seed coats, straws, weeds) other than grains, damaged grains, inorganic 
extraneous matter and harmful/toxic seeds  
 
3.6. 
 inorganic matter  
stones, glass, pieces of soil and other mineral matter  
 
 
3.7  
dusting  
 Application of dry , finely powdered pesticides which  may be mixed  with an inert carrier and applied with 
some type of blower  
 
 
4. Requirements  
 
4.1 Location  
Consideration shall be given to potential sources of contamination from the local environme nt and the 
surrounding areas  
 
4.1.1  The location of a silos shall be authorized by the competent  authority (ies).  
 
4.1.2 The topography of the location shall be in such a way that it is well drained to avoid water logging and 
natural flooding calamities  
 
4.1.3  The silo shall be located in a manner that radiant heat from the sun is minimal  
 
4.1.3  The silos shall be accessible by road and /or rail  
 
4.1.4  The silos shall have access to clean  water, communication facilities and power supply.  
 
4.1.5  The silos  shall not be near any facility where the danger of fire is constantly present  
 
4.1.6  the silo should be located away from busy public facilities such as schools and hospitals . 
 
4.1.7  There should be ample space to facilitate movement and parking of transp ort. 
 
4.2 Structural requirements  
 
4.2.1  General  
 
4.2.1.1  The construction and building materials shall conform to the National Building Regulations and 
relevant standards.  
  
4.2.1.1. 2 The materials used for construction shall be durable, nontoxic water a nd wind tight  
 
 
4.2.3  Foundation  
                                                                                                DKS 2985:2023  
 
KEBS 2023 — All rights reserved    3 The foundations shall be of adequate strength to take the weight of the building and of the grain filling, and 
should be termite proofed.  
 
4.2.4  Floor  
 
4.2.4.1 The floor shall be adequately strong and capable of withstandi ng heavy loads and vibrations.  
 
4.2.4.2 The floor shall be elevated or constructed higher than the existing ground.  
 
4.2.4.4 The floor shall be smooth, firm and easy  to clean  
 
4.2.4.6 The floor shall be free from cracks and crevices where moisture from th e ground may affect the 
stored grains or can harbor  pests.  
 
4.2.5  Walls  
 
4.2.5 .1 The internal surfaces of the walls shall be smooth, free from projections to eliminate dust -laden 
surfaces, and facilitate cleaning of the store and avoid interference with o ther operations  
 
4.2.5 .2 The junction between walls and roof shall be well sealed in order avoid birds and rodents to access 
the stored grains  
4.2.5.3  A water/damp -proof barrier shall be incorporated into the base of the walls. Water proofing 
compound may  be incorporated during the plastering and finishing of the walls.  
 
 
4.2.6  Roofs  
 
4.2.6 .1 Roof design shall be in a way that facilitates pest control and other stock management procedures.  
 4.2.6.2  The roof design shall be in such a way that it does not pr ovide hobourage for insects and pests  
 
4.2.6 .3 Internal pillars within   the silos supporting roof frames should be avoided as much as practicable as it 
affects silos operations  
 
4.2.6 .4 Roof shall be provided with the necessary lateral and vertical wind b race to resist forces due to 
strong winds and earthquakes.  
 
4.2.6.5  The roof covering materials shall be reflective and keep the silos dry.  
4.2.6.6  The inclination of the roofs shall be sufficient to drain rainwater quickly, taking into account that the 
water may be forced up by the wind.  
 
4.2.6.7  Roofs shall be watertight and gulleys kept clear of debris and leaves.  
 
4.2.6.8  The roof shall be a good thermal insulator, not affected by condensation, and give protection against 
attack by pests and moulds.  
 
4.2.6.9  Roofs with cyclones and ventilation fans shall ensure that  the condensed water is drained properly  
 
4.2.6.10 The roofing materials shall  be designed to ensure proper temperature controls in the silos  
. 
4.2.6.11 Rainwater drainpipes shall not lesser t han 90 mm in diameter.                                                                                                     DKS 2985:2023  
 
4  KEBS 2 023— All rights reserved   
4.2.6.12 All drain pipes from roof gutters shall be external, well fitted,  firmly fixed and protected from 
damage and shall have mesh baffles fitted inside their open ends .  
 
 
 
4.2.7  Doors  
 
4.2.7 .1  
 A minimum of 2 doors shall be provided in a silo.  
 
4.2.7 .2 The door shall fit tightly to facilitate effective pest control.  
 
4.2.7 .3 The door shall be made of steel  or any other material with similar properties.  
 
4.2.7.4  The door shall be provided with a secure locking system.  
 
4.2.7 .5 The size of the door shall  allow for various silo operations to be carried out. 
 
4.2.8  Ventilation  
 
4.2.8 .1  Vents shall be provided on  the roof or  any other method of aeration that is suitable .  
 
4.2.8 .2 The design of the ventilation shall be such t hat it prevents birds and pests from accessing the silo.  
 
4.2.8 .3 In addition to natural ventilation exhaust, fans may be introduced for forced ventilation.  
 
 
4.2.9  Illuminations  
 
4.2.9 .1 Illuminations inside the silos should be sufficient with lights not being too  bright or too dim  
 
4.2.9 .2 Artificial lighting is preferable for the interior of the silos,  
 
4.2.10  Fence  
 
4.2.10 .1The site of the silos shall be secured against unauthorized entry of persons and animals.  
 
4.2.10 .2 Gates shall be adequ ate for their purpose and wide enough to allow easy vehicle access . 
 
 
 
4.3 Facility requirements  
 
There shall be annex rooms, separate from the silo and  shall include the facilities for reception, offices, 
laboratory, equipment and chemical store, washroom s, changing room and showers.  
 
4.3.1  Office space and related facilities  
                                                                                                DKS 2985:2023  
 
KEBS 2023 — All rights reserved    5 The office space shall be:  
 
a) easily accessible for staff and other visitors;  
 
b)  clearly signposted;  
 
c)  well aerated;  
 
d)  safe and unobstructed; and  
 
e)  clean, naturally well -lit and suitably furnished.  
 
 
4.3.2  Toilets and urinals  
 
 
4.3.2.3 Washrooms for male and female shall be separately provided in the premises of the silos.  
 
4.3.2.4  The floor of the washrooms shall be non -absorbent, washable and non -slip. 
 
4.3.2.5  The wal l shall be constructed from non -absorbent, washable materials and shall be light coloured, up 
to a minimum height of 2 m and they shall be smooth and without crevices and shall be easy to clean and 
disinfect.  
 
4.3.2.6  The washrooms shall be furnished with hand washing facilities.  
 
4.3.2.7  The number of washrooms shall be adequate for the number of employees. The number of 
washrooms may be determined using Table 1.  
 
Table 1 — Number of washrooms in Silos  
 
SL No  Number of employees  Number of washrooms  
i) 1 – 15 1 
ii) 16 – 35 2 
iii) 36 – 55 3 
iv) 56 – 80 4 
v) 81 – 110 5 
vi) 111 – 150 6 
 
NOTE Over 150 employees, one additional fixture for each additional 40 employees.  
 
 
 
4.3.3 Changing rooms and showers  
 
4.3.3.1  The silos shall provide suitable changing  room and showers for workers.  
 
4.3.3.2  Changing rooms shall be furnished with labelled lockers.  
 
4.3.3.3  All cleaning materials shall be provided.                                                                                                    DKS 2985:2023  
 
6  KEBS 2 023— All rights reserved   
 
4.3.4 Equipment store  
 
4.3.4.1  Equipment such as for fumigation, sampling, cleaning may be provided in the  silos. Such equipment 
shall be appropriately stored and separate from the grain storage and chemical storage areas.  
 
4.3.4.2  The floor shall be non -absorbent and washable.  
 
 
4.3.5  Chemical store  
 
 
4.3.5.1  Chemicals such as pesticide, rodenticides, fumiga nts may be stored at the silos. Such chemicals 
shall be stored in a separate room under lock and key.  
 
4.3.5.2  The chemical store shall be well ventilated and the fumes released  should not be harmful to the 
environment  
4.3.5.3  Chemicals shall be clearly l abeled for easy identification.  
 
4.3.5.4  The floor and the wall shall be easy to clean.  
 
4.3.5.5  Chemical store shall be clearly identified as such.  
 
4.3.6  Laboratory  
 
4.3.6.1  The silos shall be provided with laboratory for internal control.  
 
4.3.6. 2    The laboratory  should have an adjacent office for the lab workers  
 
4.3.6.3;  The laboratory shall have facilities to undertake basic tests such as moisture content, organoleptic    
test, physical tests, aflatoxin screening and grading.  
 
4.3.6.4  The laborator y shall have adequate sample retention shelves and sample bags  with labels  
 
4.3.6.5  The laboratory shall have sufficient area for test to be conducted and the relevant equipment. These 
equipment may include moisture meters, sieves, aflatoxin screening kits , weighing balance.  
 
4.3.6.6  The laboratory equipment shall be calibrated,  serviced and maintained at scheduled intervals as per 
the equipment,  
 
4.3.6.7  The laboratory shall be well aerated  
 
4.3.6.8  The floor and the wall shall be easy to clean.  
 
4.3.6.9  The testing area shall be sufficiently lit.  
 
 
4.4 Safety requirements  
                                                                                                DKS 2985:2023  
 
KEBS 2023 — All rights reserved    7 4.4.1   The Silos and the silos site shall have Warning signs or boards displayed in hazardous/dangerous 
places  
 
4.4.2  Firefighting equipment in working condition (fire extinguishers, fire hydrants) shall be provided and 
be installed in a conspicuous and accessible location.  
 
4.4.3  There shall be provisions for well -equipped first aid facilities.  
 
4.4.4  Safety signs, fire exits, eyewash stations, shall be indicated  
 
 4.4 .5  Smoking zone s (where  smoking is allowed) shall be clearly indicated  
 
 
 
4.5 Management requirements  
 
4.5.1  Cleaning and maintenance  
 
4.5.1.1  The buildings, equipment, utensils and all other physical facilities of the establishment, including 
drains, shall be maintaine d in good and  orderly condition.  
 
4.5.1.2  The silos shall be cleaned and treated prior to any storage operation.  
 
4.5.1.3 The silos and  environment of the silos shall be kept clean and shall be disinfected / disinfested 
regularly  to prevent rodents , insect and mites infestation.  
 
4.5.1.4 Changing facilities and washrooms shall  be kept clean.  
 
 
4.5.2 Waste disposal  
 
4.5.2.1. Waste from sorting and screening shall be disposed in such a  way that does not harbour rodents 
and other pests.  
 
4.5.2.2. Waste from th e silos shall be collected and disposed in environmentally friendly  manner.  
  
 
4.5.3  Inspection, drying, screening, sorting and grading unfit materials  
 
Such operations shall be carried out in a clean and sanitary manner. Only clean, sound product shall b e 
stored.  
 
4.5.3.1  Inspection  
 
4.5.3.1.1  The general appearance of the products shall be observed during the process of unloading; if the 
grains are moist, insect infested, insect damaged, or contain an unusual amount of dirt, debris or other 
foreign mate rial. 
 
4.5.3.1.2  If the observations from sensory analysis do not allow taking the decision, a sample from the 
suspected lots shall be taken and accurate tests conducted before any acceptance of the lot.                                                                                                    DKS 2985:2023  
 
8  KEBS 2 023— All rights reserved   
Routine inspection shall be done depending on stora ge duration and at specified intervals.  
 
4.5.3.2  Drying  
 
4.5.3.2.1 If grains brought to the silos do not comply with maximum moisture content stated in relevant East 
African Standards, the grains shall be dried and moisture content reduced to the specifie d level.  
 
4.5.3.2.2  If heated air is used for moisture reduction, temperature and drying time shall be synchronized so 
that they do not result in adverse effect on the nutritional composition and quality of the grain in its intended 
use. 
 
4.5.3.2.3  If dryi ng is done under the sun, drying should be held on a clean environment on clean    drying 
sheets, preferably blue. The grain should be spread in a thin layer and raked at intervals, to remove the 
moisture.  
 
4.5.3.2.4  Whatever the drying system, care shall b e taken to avoid attack by pests.  
 
 
4.5.3.3  Screening, sorting and grading  
 
Ungraded grains shall be screened and sorted before being graded according to relevant East African 
Standards as soon as they reach the silos.  
 
4.5.3.3.1  Grains shall be screene d and/or aspirated to remove all   defective grains and foreign matter  
 
4.5.3.3.2  Screening shall be done in such a way that the  operation does not pollute the environment  
 
4.5.3.3.3  Sorting shall be done before any grain treatment to ensure the removal of all defective grains.   
 
4.5.3.3.4  Defective grains, shall be bagged separately and tagged as unsuitable for human consumption . 
 
4.5.3.3.5  Containers of defective grains shall be removed as soon as practicable from the silo area.  
 
 4.5.3.3.6  materials  which carry the danger of contamination by mycotoxins shall be diverted to non -food 
uses.  
 
4.5.4  Loading and unloading  
 
4.5.4.1 Loading and unloading may be done mechanically or manually.  
 
4.5. 4.2  Side ascending ladders for  manual loading should be provided for efficiency and safety  
 
4.5.4.3 Loading and unloading shall not take place in open area when it is raining. A canopy should be 
constructed to allow continuous loading and unloading even when it rains.  
 
 
 
4.5.7  Pests prevention and control  
                                                                                                DKS 2985:2023  
 
KEBS 2023 — All rights reserved    9 4.5.7.1 Pests can be prevented and controlled by  
 
a)  keeping grains in a modified atmosphere  
 
b)  spraying the floors and walls with pesticides;  
 
c)  dusting of grains by pesticides; and  
 
d)  fumigation.  
 
e)           Maintain the walls  and the floors fr ee from cracks and crevices  
f)         The silos shall be kept clean and tidy both inside and outside for easy management and to        keep 
away pests  
g)          rodent traps  
 
4.5.7.2 Where control is by fumigation, the following provisions shall appl y: 
 
a)  fumigants shall only be used by properly trained and authorized persons, who know the dangers and 
the necessary safeguards.  
 
b)  fumigated silos shall be kept closed and post warning signs displayed until the gas concentration is 
at the safe le vel for human beings  
 
c)  the silos shall be properly closed during  fumigation and where direct fumigation is done there shall 
be no silo imperfections, e.g. cracks in the floor, unfilled floor joints, roof leaks etc., which might 
jeopardize the success o f the fumigation.  
 
d)  at the end of the fumigation, silos shall be aerated carefully according to the standard procedure to 
minimize dangers.  
 
4.5.7.3 The control of attacks by vertebrate and invertebrate animals shall be done in accordance with ISO 
6322 -3. 
 
 
4.5.8 Structural management and maintenance  
 
4.5.8.1. Floor cracks and crevices should be repaired as soon as possible to  prevent pests and moisture in 
the silos  
 
4.5.8 .2 Storage conditions  
 
4.5.8.2.1Temperature  
The storage temperature shall be maint ained depending on the type of cereal, use and period of storage. 
Refer  to standards for individual cereals.  
 
4.5.8.2.2  Humidity  
 A hygrometer shall be  maintained  in the silo to measure the humidity levels depending on  the type of 
cereal and pulse unde r storage . 
 
4.5.8.2.3 Moisture content                                                                                                    DKS 2985:2023  
 
10  KEBS 2 023— All rights reserved  This shall be a continuous management process in the laboratory as referred to in section 4.3.6.3  
 
 
4.6 Record keeping  
 
Silos shall keep records of:  
 
a)  origin, history of and volume of each lot of cereals and/or  pulses kept;  
 
b)  laboratory tests carried out;  
 
c)  names of chemicals used for pests control;  
 
d)  fumigation detailing the fumigant used, the date and method of fumigation, person or company 
carrying out the fumigation;  
 
e)  names of employees and trai ning undertaken;  
 
f)  authorization by Environmental agency;  
 
g)  Inspection, servicing, maintena nce and  calibration of all equipment;  
 
h)  cleaning; and  
 
i)  pest control detailing the pesticide used, the date and method of spray/dusting, person or compa ny 
carrying out the pest control.  
 
j)  Dispatch records  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                DKS 2985:2023  
 
KEBS 2023 — All rights reserved    11 ANNEX 1  
(Informative Annex)  
CATEGORIES OF SILOS  
1. Private Silos : 
These are owned and managed by the channel suppliers (manufacturers/traders) and resellers and are used 
exclusively for  their own distribution activities.  
Examples:  
(a) Silos constructed by farmers/producers near their fields/places of work.  
(b) Silos owned and managed by wholesalers and retailers close to their selling centers.  
(c) Silos constructed by manufacturers near their production units.  
(d) Silos taken on rent by retail stores.  
(e) Retailers may have several regional silos  to cater the needs of their stores.  
(f) Silos owned/leased by a wholesaler where it stores and distributes. Maintaining private silos involves f ixed 
as well as variable costs. Examples of fixed costs are basically the investments made in terms of insurance, 
capital, interests and taxes. The variable costs on the other hand, include maintenance costs and operating 
costs.  
Note: when these private si los are used for commercial purposes, this standard shall apply  
2. Public Silos:  
These silos are owned by government and semi government bodies and are made available to private firms 
to store goods on payment of rent. The public silos are usually set up t o help small traders who are not in 
position to have their own silos due to financial constraints.  
Therefore, in order to promote trade and industry, central or state governments come forward to cater such 
storage needs of traders/retailers. Anyone can ava il these facilities to solve its short -term distribution needs. 
Retailers sometimes due to increased sales even find their private silos insufficient if their facilities have 
reached capacity or if they are making a special, huge purchase of products for s ome reasons.  
3. Bonded Storage:  
These silos are owned, managed and controlled by government as well as  private agencies. Bonded silos  
are storage facility used to store imported goods for which import duty is still  to be paid. The bonded silos  run 
by priva te agencies have to obtain license from the government.  
In actual, this enables the government bodies to hold control on private firms to pay their taxes on time. 
Without paying duties, importers cannot take over or open the goods. Globally, it has been se en that these 
silos are found near the ports and are usually owned by dock authorities. Bonded silos are subject to two 
types of taxes: (a) Excise duty and (b) Custom duty.  
4. Co -operative Silos : 
These silos are owned, managed and controlled by co -operativ e societies. These societies provide storage 
facilities on the most economical rates to their members only. The basic purpose to run such silos  is not to 
earn profit but to help their members.  
 
 
 
                                                                                                   DKS 2985:2023  
 
12  KEBS 2 023— All rights reserved   
Annex II  
(Informative annex ) 
competent Authorities for approving building of silos  
 
1. Building permit  
It is issued by the City planning department of the county. Can also be issued by National Construction 
Authority  
 
2. Environmental permit  
 Given by National Environmental Management Authority  
 
3. Occupancy Certificate  
Given by the municipal Authority upon completion of inspection of the building  
 
 
 
 