DEAS 931: 2018
ICS 55.120
 
© EAC 2018 – All rights reserved ii
 DRAFT EAST AFRICAN STANDARD 
Packaging ancillary materials —  Code of practice — Part 1: Desi ccants 
 DEAS 931: 2018 
© EAC 2018 – All rights reserved  iii
 Copyright notice 
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Violators may be prosecuted. DEAS 931: 2018 
iv © EAC 2018 – All rights reserved
 Foreword 
Development of the East African Standards has been necessitated  by the need for harmonizing requirements 
governing quality of products and services in the East African Community. It is envisaged that through 
harmonized standardization, trade barriers that are encountered  when goods and services are exchanged 
within the Community will be removed.  
The Community has established an East African Standards Committ ee (EASC) mandated to develop and 
issue East African Standards (EAS).  The Committee is composed of representatives of the National 
Standards Bodies in Partner States, together with the represent atives from the public and private sector 
organizations in the community.  
East African Standards are developed through Technical Committe es that are representative of key 
stakeholders including government, academia, consumer groups, p rivate sector and other interested parties. 
Draft East African Standards are circulated to stakeholders thr ough the National Standards Bodies in the 
Partner States. The comments received are discussed and incorpo rated before finalization of standards, in 
accordance with the Principles and procedures for development o f East African Standards.  
East African Standards are subject to review, to keep pace with  technological advances. Users of the East 
African Standards are therefore expected to ensure that they al ways have the latest versions of the standards 
they are implementing .  
The committee responsible for this document is Technical Commit tee EASC/TC 066, Packaging . 
Attention is drawn to the possibility that some of the elements  of this document may be subject of patent 
rights. EAC shall not be held responsible for identifying any o r all such patent rights. 
During the preparation of this Standard, reference was made to the following document: 
IS 10106, Packaging code Part 3: Desiccants  
Acknowledgment is hereby made for the assistance derived from t his source. 
DEAS 931 consists of the following parts, under the general tit le Packaging ancillary materials — Code of 
practice: 
Part 1: Desiccants  
Part [n+1]: Part title  
Part [n+2]: Part title  
 DRAFT EAST AFRICAN STANDARD DEAS 931: 2018
 
© EAC 2018 – All rights reserved 1
 Packaging ancillary materials — Code of practice — Part 1: Desi ccants 
1 Scope 
This Draft East Africa Standard gives the guidelines on the sel ection and use of desiccants in packaging. 
2 Normative references 
The following documents are referred to in the text in such a w ay that some or all of their content constitutes 
requirements of this document. For dated references, only the e dition cited applies. For undated references, 
the latest edition of the referenced document (including any am endments) applies. 
ISO 15106-3, Plastics — Film and sheeting — Determination of water vapour transmission rate — Part 3: 
Electrolytic detection sensor method  
3 Terms and definitions 
For the purposes of this standard, the following definitions sh all apply. 
3.1 
barrier 
any material providing physical shield against ingress of water -vapour which causes  deterioration to the 
packaged article. This may be used in the form of a liner or as -a coating 
3.2  
desiccant  material used to  take up water-vapour from the air-space within a container or f rom air passed through it 
3.3 
dunnage 
any materials within the barrier other than the packaged item, for example, packing or blocking materials, 
instrument cases, etc. 
3.4 
hygroscopic 
capable of absorbing water-vapour from the surrounding atmosphe re. Absorption will continue until equilibrium 
is reached and this is dependent upon the conditions of tempera ture and relative humidity of the atmosphere. 
For many substances, this is a reversible process so that if th e moisture content is in excess of the equilibrium 
value water-vapour will be given off until equilibrium conditio ns are established 
3.5 
basic desiccant 
product capable of absorbing 27 % of moisture on its dry weight  at 50 % relative humidity and 25 °C 
3.6 
ancilliary materials 
materials associated with packaging operations but are not inte nded to be part of the final product. They 
includes but not limited to dessicants, staple pins, adhesives,  packaging tapes, Straps, packaging machinery. 
  
2 © EAC 2018 – All rights reserved
 4 Packaging environment 
4.1 General 
Dampness not only encourages corrosion but can also cause growt h of molds and bacteria even when water 
is not present. Various steps can be taken to reduce the advers e effect of moisture on a packed article such 
as application of temporary protective treatment against corros ion to metallic surfaces or the proofing of 
textiles. Such direct protection is not practicable for all art icles, especially for certain electrical components of 
scientific and optical instruments.  
An ideal method of providing protection in such instances is by  using a completely sealed package. There 
may still be damp inside the container, and the moisture may be  given off by cushioning material used to hold 
the articles in position. Furthermore, few materials used in ma king sealed packages are completely resistant 
to penetration of water vapour and a certain amount of moisture  may reach the articles through the walls of 
the package. Desiccants are, therefore, essentially used to tak e-up moisture that may be in package from any 
of these sources. 
4.2 Humidity 
4.2.1 General 
4.2.1.1  Air naturally contains moisture in the form of vapour. The qua ntity of moisture present in a unit 
volume is known as absolute humidity. At any particular tempera ture, the air can hold only a limited amount of 
water-vapour; the higher its temperature, the more water vapour  the air can hold. Air containing as much 
water-vapour as it can hold is said to be saturated. If saturat ed air is cooled, it will give up by condensation 
just enough of its moisture as liquid water to leave it saturat ed at the lower temperature. 
4.2.1.2  The maximum quantity of moisture which can be held in vapour f orm by the atmospheric air is 
determined by the temperature. The hygrometric tables and chart s provide this data for a whole range of 
temperature. 
4.2.2 Relative humidity  
4.2.2.1 Normally air is not saturated with water-vapour unless it is in  close contact with liquid water. The 
actual amount of water vapour present in air (‘that is, the abs olute humidity) expressed as a percentage of 
amount the air contains when saturated at the same temperature is called the relative humidity or RH. For 
example, suppose a cubic metre of air contains 5 g of water vap our and that air if saturated at the same 
temperature would contain 20 g of water vapour per cubic metre,  then the air has a relative humidity of: 
%25100205
 
Saturated air has relative humidity of 100 % 
4.2.2.2  The relative humidity of atmosphere is the dominating factor i n determining whether the corrosion of 
metals, mould growth, rotting etc., will take place. It is know n, for example, that at ordinary temperatures, 
corrosion of iron is extremely slow at relative humidity below 60 % but becomes rapid at higher humidities. 
Mould growth does not in general take place or is extremely slo w unless the relative humidity is above 70 %. 
Generally, for engineering products a 50 % relative humidity le vel has been found to be the critical level and 
provides a tolerance against a sudden fall in temperature but f or other products, other critical levels may 
apply.  
© EAC 2018 – All rights reserved  3
 5 Desiccated packages 
5.1 General 
5.1.1  The deterioration of many articles can be minimized by applyin g suitable treatment to the article itself 
either during or after manufacture. Sometimes such treatment is  not practicable or desirable and it is still 
necessary to protect the contents. One method of doing this is to ensure that the relative humidity of the 
atmosphere in contact with the item never exceeds a safe limit which is generally taken in practice to be 50 %. 
5.1.2 A package that contains a sufficient quantity of suitable desic cant to ensure that the RH within it will 
not exceed this figure when stored in any part of the world for  a specified period is called desiccated package. 
An essential requirement of such a pack is that it should conta in sufficient quantity of a suitable desiccant to 
reduce the relative humidity within the pack to 50 % or less an d maintain this for the desired period. To assist 
in maintaining this reduced level of humidity, the entry of wat er-vapour is retarded.  
5.1.3 There are various ways of achieving this. Hermetically sealed m etal containers may be used, or the 
container may incorporate or be made from  a water-vapour barrier, that is a material with a high resistan ce to 
the passage of water-vapour. It is rarely possible to exclude a ir from such packages or to avoid the use of 
interior packaging materials that contain some moisture. 
5.2 Sources of moisture 
5.2.1  The air inside the barrier contains some water-vapour. 
5.2.2 The air outside the barrier is the most important source of moi sture even in a sealed container except 
a perfectly sealed metal or glass container which may be comple tely water-vapour proof. 
Air-tightness is an even less reliable criterion than waterproo fness. The implication of this is that if the relative 
humidity outside the package is higher than inside, there is a tendency for moisture to pass into the package. 
Often in many countries, the relative humidity is 80 % to 100 %  and since that of the atmosphere inside the 
package is to be kept below 50 %; the transmission of water-vap our may be considerable. 
5.2.3  Hygroscopic material inside the barrier is a considerable sour ce of moisture. For example, wood and 
paperboard are both hygroscopic and will give up moisture if te mperature rises. The packaged item itself may 
create a problem if it’s made from hygroscopic materials. 
5.2.4 Trapped water, there is always a possibility of water being tra pped within the article, for  example, in 
pumps after testing, or water being entrained in any oil remain ing in an oil bath. Certain  non-hygroscopic 
materials used for packaging contain water as a result of their  manufacturing process. Expert guidance should 
be sought to deal with this problem.  
6 Factors determining choice of desiccant 
6.1 General management of the desiccant 
6.1.1 A desiccant maintains a safe relative humidity within the packa ge by absorbing moisture from the air 
and any moisture arising from the goods internal hygroscopic ma terials. It will further absorb any moisture 
which enters the package through the barrier but only for a cal culated period. 
The desiccant should be in a dust proof container that will pre vent its spreading throughout the pack and at 
the same time allow the desiccant to absorb the moisture from t he atmosphere within the pack. 
6.1.2 There are many dehydrating agents that can be used but certain properties such as moisture  
absorbing capacity, chemical inertness, etc. makes some materia ls more suitable than others for use as 
desiccants in packaging.  
4 © EAC 2018 – All rights reserved
 6.2 Important factors  
6.2.1 Moisture absorbing capacity of desiccant in relation to b ulk and mass   
To maintain a safe relative humidity inside a desiccated packag e, it is essential to have present sufficient 
desiccant to cater for all possible sources of moisture. In ord er to minimize the space required in the package 
for desiccant, it is desirable to use materials of high moistur e absorbing capacity. 
6.2.2 Stability and physical form of the desiccant 
6.2.2.1 The physical form of the desiccant should such that it exposes maximum surface of desiccant and 
allow diffusion of package atmosphere through its mass. The des iccant container should be designed to 
minimize hindrance to such diffusion. These conditions are best  satisfied if the desiccant is available in the 
form of coarse granules, or tablets.  
6.2.2.2 The desiccant should retain its form throughout the performance  of its function, i.e. should remain 
solid and dry to the touch and suffer little or no disintegrati on. The material should be such that the absorption 
of moisture is not by chemical changes that will cause it to co rrode or otherwise damage its container or the 
article packed. It should not produce a liquid or gas or a sign ificant rise in temperature. 
6.2.2.3 Influence of normal temperature range on the moisture absorbing  capacity of desiccant. 
Desiccants remove moisture from the atmosphere in one of the tw o ways, for example: 
a) Physically, and b) Chemically. 
6.2.2.4 Moisture taken up by chemical combination is firmly held and is  not liberated by temperature 
increase normally encountered in the environment. 
6.2.2.5  Moisture taken up physically is held less firmly and an increa se in temperature can cause the 
desiccant to give up moisture to the atmosphere. It is importan t, therefore, that those desiccants which take up 
moisture physically should not give it up again in sufficient q uantities to affect materially the relative humidity if 
the temperature rises. 
6.2.3 Means of containing the desiccant 
It is essential that the moisture in the package should be able  to reach the desiccant and that the desiccant or 
dust from it should not be allowed to spread throughout the pac kage. For this reason, importance is attached 
to the containers in which the unit quantities of desiccant are  held. The considerations discussed in clause 5 
should, therefore, be taken into account in selecting a unit co ntainer for the desiccant. The unit containers 
should be firmly anchored and properly distributed inside the p ackage.  
The desiccants may be indicative or non-indicative type of mois ture (on losing its activation) changes in 
colour. 
6.3 Commonly used desiccants for packaging 
The following are commonly used desiccants for packaging : 
a) silica gel, 
b) activated alumina, and 
c) activated clays.  
© EAC 2018 – All rights reserved  5
 7 Quantity of desiccant 
7.1 General 
7.1.1  Type of water-vapour barrier. The layer or layers of the packa ge that are intended to exclude water-
vapour constitute the water-vapour barrier. Some barriers will allow the passage of water-vapour only at an 
extremely slow rate but even at this rate, the relative humidit y may become dangerously high in the absence 
of a desiccant after a few days under humid conditions. 
7.1.2  The important factor is the Water-Vapour Transmission Rate (WV TR) of the barrier material. This rate 
is determined experimentally under standard conditions and is e xpressed in grams per m2 per 24 h. Typical 
figures for WVTR for some of the materials are given in Table 1 . 
Table 1 — WVTR of various materials at 38 °C and 90 % RH 
S/N Material Thickness  
(µm) Typical WVTR 
(g/m2 24 h) Test method 
i. Low density polyethylene 65 10 
ISO 15106-3 150 3.4 
250 2 
ii. High density polyethylene 25 25 
iii. Cross linked orientated polyethylene 75 3.5 
150 2.6 
iv. Polypropylene 50 2.3 
v. Polyvinyl chloride (PVC) 100 31 
225 9 
vi. Polyester 60 
120 11 
4 
vii. Polyvinylidene chloride (PVDC) 25 5 
viii. Fluorocarbon co-polymer 250 0.15 
ix. Aluminium foil laminate 75 0.05 
 
7.1.3  From the transmission rate, it is possible to  calculate the quantity of desiccant necessary to keep the 
relative humidity inside a package below the critical level for  any specified period under the climatic conditions 
it is expected to encounter. The better the barrier, the less t he desiccant required; if no moisture can enter, no 
desiccant is required to deal with it though it would still be necessary to absorb moisture derived from interior 
packaging material and enclosed air. Any seals employed should at least be as adequate as the barrier 
material. 
7.1.4 In service packaging, water-vapour barriers are classified as f ollows: 
a) water-vapour resistant : offers a high resistance to the passage of water-vapour. Wate r Vapour 
Transmission Rate (WVTR) shall not exceed 8 g/m2 per 24 h when measured at a temperature of 38 
°C and a relative humidity of 90 %; 
b) water-vapour proof:  Offers a high resistance to the passage of water-vapour; the w ater-vapour 
transmission rate (WVTR) shall not exceed 1 g/m2 per 24 h when measured at a temperature of 38°C 
and a relative humidity of 90 %. 
7.1.5  Area of the barrier - The surface area should be kept as small  as possible. Formatted:  p3, Adjust space between Latin and Asian
text, Adjust space between Asian text and numbers
Formatted:  Table title, Left, Adjust space between Latin
and Asian text, Adjust space between Asian text and
numbers 
6 © EAC 2018 – All rights reserved
 7.1.6  Weight of hygroscopic material inside the barrier - Sufficient  desiccant should be used to absorb 
moisture given off by hygroscopic materials such as wood and pa perboard present inside the water-vapour 
barrier and thus reduce the relative humidity to a safe value. All hygroscopic materials tend to reach 
equilibrium with the surrounding atmosphere at a relatively slo w rate. If a desiccant is used, equilibrium is 
reached between the moisture in the package atmosphere and that  in the hygroscopic material and the 
desiccant. It is necessary, therefore, to include enough desicc ants to absorb the moisture that may be given 
off by the hygroscopic material at elevated temperatures and to  ensure that the relative humidity can in no 
circumstances be above 50  %. 
7.1.7  Required period of storage - It is the total time elapsing bet ween sealing the package by the packer 
and its first opening. 
7.1.8  Volume of air inside the barrier - The volume of air inside th e package contains water-vapour and 
allowance for this is made in the calculations given under 7.2.  
7.1.9  For extremely sensitive articles, the outer packing is prefera bly done in a partially dehumidified room 
particularly during the wet season. 
7.2 Calculation of quantit y of desiccant required 
7.2.1 Basic desiccant 
There are several different types of desiccants which may be us ed for several applications, all of which have a 
differing moisture absorption capability. As it is not practica l to redefine the formulae for each type of 
desiccant, the calculations are based on the concept of basic d esiccant. 
7.2.2 Formulae 
a) Where goods are shipped through, or stored in tropical condi tions commercial distribution and 
warehousing practice;  
W = 40 ARM  + DF 
b) Where goods are shipped and stored in temperate climates sub ject to normal commercial practice  
W = 11 ARM  + DF 
c) Where goods are packed to military specifications for extend ed storage periods of not less than two 
years  
Unheated covered storage worldwide W = 24ARM + DF  
Heated covered storage worldwide W = 6ARM + DF  
d) Where goods are packed in a container manufactured from a wa ter-vapour impervious material, such 
as, glass or metal fitted with a removable closure and when the  sealing gasket is known to be capable 
of water-vapour transmission, the formulae in (d) become; 
Non-thermally insulated W = 170 V + 90 Rs LM + DF  
Thermally insulated W = 70 V + 90 RS LM + DF  
where 
W is the  mass of basic desiccant in g; 
A is the  area of water-vapour barrier in m2; 
M is the  maximum storage time in months;  
© EAC 2018 – All rights reserved  7
 R is the  water-vapour transmission rate of the barrier measured at 90 % RH and 38 °C in g/m2 per 24 
h; 
V is the  volume of free air inside the barrier in m3; 
L is the  length of seal (gasket) in m; 
RS is the  water-vapour transmission rate of the seal in g/m length 24 h; 
D is the  mass of dunnage inside the barrier in g; and 
F is the factor dependent upon the type of dunnage used as follow s: 
1/5 for timber of moisture content greater than 14 %; 1/8 for felt, carton board and similar packaging materials; 1/10 for plywood and timber with less 14 % moisture content; an d 
0 for expanded polyethylene or expanded polystyrene. 
8 Conditions in use for desiccants 
In order that the desiccant shall be fully effective in use, it  is imperative that: 
a) the desiccant is in a fully activated condition; 
b) it can be reached by the air within the water-vapour barrier  but is prevented from spreading; 
c) over the items in the package; d) it is in perfect condition as regards its moisture-absorbing  capacity when it is placed within; 
e) the barrier; and f) as much as possible of the dunnage material is placed outsid e the barrier. 
NOTE Annex A describes method of test for desired conditions of  the packaging.   
8 © EAC 2018 – All rights reserved
 Annex A 
(informative) 
 
Methods of meeting desired conditions 
A.1 The desiccant should be in unit containers such as bags or sac hets which should be fastened securely 
within the water-vapour barrier so that they will not wander or  chafe. 
A.2. Bags of desiccant are available in various sizes providing qua ntities of any particular desiccant 
equivalent in moisture-absorbing capacity to weight units of ba sic desiccant. Commercial desiccants can be 
obtained in unit containers equivalent to 25 g, 50 g, 100 g, 25 0 g, 500 g, 1 kg, 2.5 kg and 5 kg of basic 
desiccant. 
A.3 In order to achieve the requirement mentioned in 8.1 b), the u nits should be packed, transported and 
stored in sealed metal containers. The latter should be kept cl osed until the packer is ready to transfer and 
seal the required amount of desiccant into a space within the w ater-vapour barrier, the metal container being 
closed immediately after transfer. It is not usually a good pol icy to obtain a bulk container of such a size that it 
has to be continually opened and shut in order to withdraw smal l numbers of units. It is preferable to have a 
larger number of small bulk containers. Indicator papers enclos ed in the container should be checked as a 
guide whether the desiccant is still in good condition. 
A.4 The quantity of desiccant required for a particular package ca n be pre-determined by calculation. The 
distribution of the desiccant requires careful thought so that,  wherever possible, the size of the barrier is not 
increased to accommodate the desiccant. Where dimensions are cr itical, the use of an alternative or thicker 
barrier material should be considered. It is often possible to utilize the empty spaces within the barrier by 
breaking down the total quantity of desiccant required into con venient units.  
A.5 Desiccant should not be removed from its unit container in ord er to add small quantities to a package. 
Unit containers only should be used. It is sometimes advisable to make separate compartments for the 
necessary unit containers, both for convenience in packing and unpacking, and ease of securing, but if this 
method is adopted then adequate provision must be made to ensur e a free circulation of air within the barrier. 
Material is used for these compartments, due allowance must-be made if hygroscopic. 
In the packaging of certain items, such as precision instrument s, it is essential to prevent desiccant dust from 
escaping from its container. Special containers are available f or this purpose. To safeguard against accidental 
sifting of desiccant from the unit containers, it is advisable that the packaged item be suitably protected so that 
the dust cannot filter into small orifices, oil holes, etc. 
A.6 Desiccant which for accidental or other reasons have been expo sed to the atmosphere should never be 
introduced or re-introduced into the barrier. Where goods are s ent for export shipment, there is a danger of 
the water-vapour-proof barrier being damaged by customs examina tion and steps should be taken to avoid 
this, otherwise it may be necessary to re-desiccate and reseal the package. When calculating the amount of 
desiccant required, it is desirable to allow for unforeseen del ays in transit. The expiry date should always be 
stamped on the package. 
  
© EAC 2018 – All rights reserved  9
 Bibliography 
KS 2718, Packaging code — Ancillary materials — Desiccants  
 DEAS 931: 2018 
 
© EAC 2018  – All rights reserved