Reference number  
DRS 393 -2: 2018  
© RSB 2018  
 
 
 RWANDA 
STANDARD  DRS  
393-2 
 
First edition  
2018 -mm-dd 
 
Spatial application mosquito repellents — 
Specification — 
Part 2 
Spray (aerosol dispensers)  
  DRS 393 -2: 2018  
©RSB 2018 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2018  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 393 -2: 2018  
iii                ©RSB 2018 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ....................  v 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Term s and definitions  ................................ ................................ ................................ ..................  1 
4 Requirements  ................................ ................................ ................................ ................................  3 
4.1 General  ................................ ................................ ................................ ................................ ..........  3 
4.2 Active ingredient and synergist  ................................ ................................ ................................ .. 4 
4.2.1  Natural repellents  ................................ ................................ ................................ .........................  4 
4.2.2  Synthetic repellents  ................................ ................................ ................................ .....................  4 
4.2.3  Synergist content  ................................ ................................ ................................ .........................  5 
4.3 Specific requirements  ................................ ................................ ................................ ..................  5 
4.4 Stability  ................................ ................................ ................................ ................................ ..........  6 
4.5 Biological efficacy  ................................ ................................ ................................ ........................  6 
5 Sampling  ................................ ................................ ................................ ................................ ....... 6 
5.1 General  ................................ ................................ ................................ ................................ ..........  6 
5.2 Sampling, testing and acceptance  ................................ ................................ .............................  6 
6 Packaging and Labelling  ................................ ................................ ................................ .............  7 
6.1 Packaging  ................................ ................................ ................................ ................................ ...... 7 
6.2 Labelling  ................................ ................................ ................................ ................................ ........  7 
Annex  A (normative)  Solvents not permitted for use in aerosols  ................................ .......................  9 
Annex  B (normative)  Determination of pressure in finished aerosol packs  ................................ .... 11 
B.1 Introduction  ................................ ................................ ................................ ................................ . 11 
B.2 Objectiv e ................................ ................................ ................................ ................................ ..... 11 
B.3 Scope  ................................ ................................ ................................ ................................ ...........  11 
B.4 Apparatus  ................................ ................................ ................................ ................................ .... 11 
B.5 Working operation  ................................ ................................ ................................ ......................  11 
B.6 Accuracy of measurement  ................................ ................................ ................................ ........  12 
B.7 Test report  ................................ ................................ ................................ ................................ ... 12 
Annex  C (normative)  Evaluation of discharge rate of filled aerosol dispensers  .............................  13 
C.1 Scope  ................................ ................................ ................................ ................................ ...........  13 
C.2 Principle  ................................ ................................ ................................ ................................ ...... 13 
C.3 Apparatus  ................................ ................................ ................................ ................................ .... 13 
C.4 Procedure  ................................ ................................ ................................ ................................ .... 13 
C.5 Calculation  ................................ ................................ ................................ ................................ .. 14 
C.6 Reporting  ................................ ................................ ................................ ................................ ..... 14 
Annex  D (normative)  Testing of valves of filled aerosol dispensers for clogging  ..........................  15 
D.1 Apparatus  ................................ ................................ ................................ ................................ .... 15 
D.2 Procedure  ................................ ................................ ................................ ................................ .... 15 
Annex  E (norma tive)  Determination of DEET content  ................................ ................................ ........  16 
E.1 General  ................................ ................................ ................................ ................................ ........  16 
E.2 Apparatus  ................................ ................................ ................................ ................................ .... 16 
E.3 Preparation of calibration curve  ................................ ................................ ...............................  16 
E.4 Procedure  ................................ ................................ ................................ ................................ .... 16 DRS 393 -2: 2018  
©RSB 2018 - All rights reserved                  iv 
 E.5 Calculation  ................................ ................................ ................................ ................................ .. 17 
Annex  F (normative)  Determination of permethrin  ................................ ................................ ............  18 
F.1 Reagents  ................................ ................................ ................................ ................................ ..... 18 
F.2 Apparatus  ................................ ................................ ................................ ................................ ... 18 
F.3 Operating conditions  ................................ ................................ ................................ .................  18 
F.4 Procedure  ................................ ................................ ................................ ................................ ... 18 
F.5 Calculation  ................................ ................................ ................................ ................................ .. 19 
Annex  G (normative)  Flame propagation  ................................ ................................ ............................  20 
G.1 Principle  ................................ ................................ ................................ ................................ ...... 20 
G.2 Apparatus  ................................ ................................ ................................ ................................ ... 20 
G.3 Procedure  ................................ ................................ ................................ ................................ ... 20 
Annex  H (normative)  Determination of pH value  ................................ ................................ ................  21 
H.1 General  ................................ ................................ ................................ ................................ ........  21 
H.2 pH of aqueous dispersions (Method A)  ................................ ................................ ...................  22 
H.3 pH of aqueous dispersion (Mathod B*)  ................................ ................................ ...................  22 
 DRS 393 -2: 2018  
v                ©RSB 2018 - All rights reserved  
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS 393 -2 was prepared by Technical Committee RSB/TC 015, Pharmaceutical Products . 
DRS 393  consists of the following parts, under the general title Spatial application mosquito repellents — 
Specification : 
 Part 1: Coils  
 Part 2: Spray  (aerosol dispensers)  
Part 3: Candles  
Part 4: Papers  
Part 5: Liquid vaporizers  
Part 6: Vaporizing m ats 
 Part 7: Tablets  
 Part 8: Liquid detergents  
Committee membership  
The following organizations were represented on the Technical Committee on Pharmaceutical Products 
(RSB/TC 015) in the preparation of this standard.  
National Industrial Research and Development Agency (NIRDA)  
National Pharmacy Council (NPC)  
University of Rwanda/College of Sciences and Technology (UR/CST)  
Pharmacie NOVA  
Rwanda Development Board (RDB)  
AGROPY LTD  DRS 393 -2: 2018  
©RSB 2018 - All rights reserved                  vi 
 IKIREZI NATURAL PRODUCTS  
HORIZON/SOPYRWA  
Rwanda Social Security Board (RSSB)  
Pharmavie  
University of Rwanda/College of Medicine and Health Sciences (UR/CMHS)  
Rwanda Biomedical Center/ Malaria and Other Parasitic Diseases Division  (RBC/MOPDD)  
Society for Family Health  (SFH) – Rwanda  
Rwanda Biomedical Center/Medical Procurement and Production Division (RBC/MPPD)  
INES - RUHENGERI  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 393 -2: 2018  
vii                ©RSB 2018 - All rights reserved  
 Introduction  
Insecticides are used either for killing or controlling harmful insects. The insecticides which are applied for 
repelling insects are termed as “Repellents". Mosquito is one of the most harmful insects for mankind. To destroy 
them, many preparations are available on the market in various recipes like pest killer spray, soap, oil, powder, 
repellent etc. Out of these, mosquito repellent is the most popular as it has germicidal and disinfectant properties 
and is able to repel mosquitoes and is convenient to use.  
 
The mosquito repellent is used for warding off mosquitoes which is the most harmful insect. Nowadays, 
mosquito repellents are used for controlling mosquit o and are complementing other mosquito destroyers 
gradually. With the rise in the standard of living, increasing urbanization and population, the demand of mosquito 
repellent mat is constantly increasing particularly in tropical places. It is a convenient method for protection 
against mosquito, so it has a tremendous market potential. Thus there is a very good scope for development of 
such units in the country . 
Spatial repellent are chemical products designed to be 'active' (requiring heat or electricity) o r 'passive' (requiring 
no heat or electricity) and  release volatile chemicals into the air  within the treated space. Product examples that 
are currently available  include mosquito coils, spray s, candles , papers, liquid vaporizers, vaporizing mats, 
tablet s, liquid detergents,  among others . However, many more  types of spatial repellent products are waiting to 
be developed.   
Spatial repellents elicit ‘spatial repellency’ which refers to a range of insect behavio urs induced by airborne 
chemicals that result in a reduction in human -mosquito contact.  These behavio urs include: movement away 
from a chemical stimulus, attraction -inhibition and/or, and feeding inhibition.  
 
 
 DRS 393 -2: 2018  
1                ©RSB 2018 - All rights reserved  
 Spatial application mosquito repellents — Specification — Part 2: Spray 
(Aerosol dispensers)  
1 Scope  
This Draft Rwanda S tandard prescribes the requirements sampling and test methods for spatial application 
mosquito repellents formulated and prepared as aerosol dispensers . 
2 Normative references  
The following documents are referred to in the text in such a way that some or all of  their content constitutes 
requir ements of this document.  For dated references, only the edition  cited applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
RS 91, Labeling and marking of pharmaceutical products — Specification  
AOAC 997.07, N-octyl Bicycloheptene dicarboximide (MGK 264), Pyrethrins and Piperonyl Butoxide (PB O) in 
Technical materials, concentrates and Finished Products.  
DRS 394-2, Mosquito repellents ― Performance Test Guidelines ― Part 2: Spatial  repellents  
RS 191, Refined pyrethrum concentrate ― Specification  
AOAC 973.12, d-trans -Allethrin in pesticides formulations  
CIPAC 741, Determination of transfluthrin content  
CIPAC 743 , Determination of prallethrin (etoc) content  
CIPAC 993,  Determination of Metofluthri n (S1264)  
CIPAC 742,  Determination of d -allethrin  
CIPAC 977,  Determination of Meperfluthrin  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply  
3.1 
mosquito   
©RSB 2018 - All rights reserved                  2 
 any of numerous arthropod animals of the class mosquito, having an adult stage characterized by three pairs 
of legs and a body segmented into head, thorax, and abdomen and usually having one or two pairs of wings.  
3.2 
mosquito repellent  
substance applied to skin, clothing, or other surfaces which disco urages mosquito  (and arthropods  in general) 
from landing or climbing on that surface  
3.3 
natural repellents/biopesticide s 
repellents that contain natural, plant -based  active ingredients  
3.4 
synthetic repellents  
conventional repellents containing synthetic chemical active ingredients and carrier synthetic ingredient  as 
approved by a competent authority . 
3.5 
aerosol dispenser  
device designed to produce a fine spray of liquid or solid particles that can be suspended in a gas such as the 
atmosphere. When a valve is released, the propellant forces the substance through an atomizer and out of the 
dispenser  in the form of a fine spray.  
3.6 
Transfluthrin  
(1R,3S)-3-(2,2-Dichlorovinyl) -2,2-dimethyl -1-cyclopropanecarboxylic acid  (2,3,5,6 -tetrafluorophenyl)methyl 
ester  
3.7 
Etoc  
Prallethrin. (S)-2-methyl -4-oxo-3-prop-2-ynylcyclopent -2-enyl(1R) -cis, trans -2,2-dimethyl -3-(2- 
methylprop -1-enyl) cyclopropanecarboxylate  
3.8 DRS 393 -2: 2018  
3                ©RSB 2018 - All rights reserved  
 Metofluthrin  
C18H20F4O3, 2,3 ,5,6-Tetrafluoro -4-(methoxymethyl)benzyl 2,2 -dimethyl -3-(prop -1-en-1-yl) 
cyclopropanecarboxylate  
 
3.9 
d-Alethrin  
(RS)-3-allyl-2-methyl -4-oxocyclopent -2-enyl (1R) -cis, trans -chrysanthemate  
3.10  
Meperfluthrin  
C17H16Cl2F4O3, [2,3,5,6 -tetrafluoro -4-(methoxymethyl)phenyl]methyl (1R,3S) -3-(2,2-dichloroethenyl) -2,2-
dimethylcyclopropane -1-carboxylate  
3.11 
PBO  
Piperonyl butoxide  
3.12 
MGK 264  
N-octyl Bicycloheptene Dicarboximide  
4 Requirements  
4.1 General  
4.1.1 The product shall consist of a liquid formulation  in a pressurised, non -refillable aerosol dispenser, 
containing propellant(s), synergist(s) and other formulants as required, intended for release of the active 
ingredient into the air in the form of an aerosol.  
4.1.2 The aerosols shall not contain solven ts and propellants listed in annex A.  
4.1.3 The formulation  shall be of uniform colour and shall be free from visible impurities.  
4.1.4 When applied, the product shall have the benefit of repelling mosquitoes.   
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 4.2 Active ingredient and synergist  
4.2.1  Natural repell ents 
4.2.1.1  Active ingredients used in natural repellents shall be natural plant based compounds such as essential 
oils or any other  plant extract approved as mosquito repellents.  
4.2.1.2 The manufacturer  shall provide adequate data on the repellence of such ingredients.  
4.2.1.3 The manufacturer  shall have adequate data justifying the proportion of ingredient(s) for which claims 
are made, used in the product.  
4.2.1.4 The essential oils and plant extracts used in natural repellents shall be, but not limited to:  
a) Cedarwood oil ; 
b) Tea tree oil ; 
c) Geranium oil ; 
d) Rosemary oil ; 
e) Lemongrass oil ; 
f) Citronella oil ; 
g) Soybean oil;  
h) Eucalyptus oil ; 
i) Cinnamon oil . and 
j) Neem oil  
4.1.2.5 The proportion of single or blended essential  oil in natural repellent shall be set by the manufacturer in 
accordance with specific standard s of the essential oil used  and records shall be availed.  
4.1.2.6 Pyrethrum extracts such as pyrethrin s shall be considered in natural repellents. The limits of pyrethrin s 
in natural repellents shall not be less than 0.25 % and the extract used shall meet the requirements of RS 191.     
4.2.2  Synthetic repellents  
4.2.2.1  Synthetic repellents shall contain synthetic chemical compounds which are able to discourage 
mosquitoes and send them flying or crawling away.  DRS 393 -2: 2018  
5                ©RSB 2018 - All rights reserved  
 4.2.2.2  If a synthetic chemical compound is blended with other active ingredient (s), either natural or synthetic, 
the proportion shall be set by the manufacturer based on scientific research and records sh all be availed.  
4.2.2.3  Active ingredients and their content in synthetic repellents shall meet the requirements prescribed in 
table 1.  
Table 1 — Active ingredients content for synthetic repellents  
S/N Active ingredient  Limits  (%, w/w)  Identification method  
1 Pyrethrins , % by mass, max  0.5 RS 191  
2 Picaridin , % by mass  0.2 – 5 CIPAC 740  
3 DEET , % by mass  5 – 50 Annex E 
4 Permethrin, % by mass, max  13 Annex F 
5 Transfluthrin , % by mass, max  1 CIPAC 741  
6 Etoc, % by mass  0.5 – 1.5 CIPAC 743  
7 Metofluthrin  (S1264), % by mass, 
max 1.82 CIPAC 993  
8 d-Alethrin  (Pynamin Forte), % by 
mass, max  0.5 CIPAC 742  
9 Meperfluthrin , % by mass, max  0.05 – 0.1 CIPAC 977  
10 Synergists, % by mass  As declared  AOAC 997.07  
 
4.2.2.4  Synthetic repellents and their active ingredients shall be approved and registered by competent 
authority  before being released to the market . 
4.2.3  Synergist content  
4.2.2.1  The synergist content shall be declared and, when determined, the average content measured shall 
not differ from  those declared.  
4.2.2.2  The synergist shall be PBO, sesame seed oil (sesamin, sesamolin) and/or MGK 264.  The synergist 
shall be tested in accordance with AOAC 997.07. The ratio of the active ingredient to the synergist shall be 
indicated and records availed.  
4.3 Specific requirements  
The product shall comply with the quality requirements given in table 2. 
Table 2 – Specific requirements  
S/N Parameters  Requirements  Test methods  
i.  Internal pressure , ºC 30 ± 2  Annex B 
ii.  Discharge rate , g formulation/sec  1 Annex C 
iii.  pH 5.5 – 7  Annex H 
iv.  Clogging of aerosol dispenser valves  No clogging shall 
occur  Annex D  
©RSB 2018 - All rights reserved                  6 
 4.4 Stability  
Stability at elevated temperature ; After storage at 54 ±2ºC for 14 days, the determined average active 
ingredient content must not be lower than 95% relative to the determined average content found before storage 
and the formulation shall continue to conformto  the requirements  of the produc t. 
4.5 Biological efficacy  
When tested in accordance with DRS 394 -2, the product shall repel 100  % of the mosquitoes available in space, 
within  protection time indicated by the manufacturer . 
5 Sampling  
5.1 General  
5.1.1 Samples shall be stored in such a manner that there is no deterioration of the material.  
5.1.2 The sampling instrument shall be clean and dry.  
5.1.3 Samples shall be protected against contamination.  
5.2 Sampling, testing and acceptance  
5.2.1 In any consignme nt, all the master cartons containing containers of the same type shall constitute a lot.  
5.2.2 Samples shall be drawn from each lot and individually tested to ascertain whether the material complies 
with the specified requirements.  
5.2.3 Any sample fail ing to comply with the specified requirements shall be termed as defective. The 
acceptance number shall be the maximum number of defective samples permissible for a lot to be accepted.  
5.2.4 The number of containers to be drawn from the lot and the accept ance number shall be as shown in the 
following Table.  
Table 1  — Number of containers to be drawn from the lot and the acceptance number  
Total number of 
containers in lot  Number of 
containers to 
be tested  Acceptance 
number  
300 or less  
301 to 1200  
1201 to 2000  
2001 to 7000  
7001 to 15000  
15001 to 24000  
24001 to 41000  
Over 41000  3 
6 
13 
21 
29 
48 
84 
126 0 
1 
2 
3 
4 
6 
9 
13 DRS 393 -2: 2018  
7                ©RSB 2018 - All rights reserved  
 5.2.5 Each of the containers to be tested shall be drawn from a different master carton which shall be selected 
at random. In order to ensure randomness of selection, random number tables shall be used. If such tables are 
not available, the following procedure may be adopted : starting from any master carton, count the master 
cartons as 1, 2, 3...... r in a systematic manner. Every rth carton shall be drawn, r being the integral part of N/n, 
where N is the total number of master cartons in the lot and n the number of master cartons to be selected.  
6 Packaging and Labelling  
6.1 Packaging  
6.1.1 The product shall be packaged in aerosol  container s that shall protect the contents and shall not react 
with the product  or cause any contamination during storage, handling , transportation or use.  
6.1.2 Filled aerosol containers shall be appropriately classified in terms of flame propagation characteristi cs 
of their contents when tested in accordance with annex G. 
a) Highly flammable — if the average length of the flame is greater than 0.45 m or if the flame burns 
back to the actuator, or continues to burn when the test flame is extinguished.  
b) Flammable — if the average length of the flame is between 0.20 m and 0.45 m  
c) Non-flammable — if the product does not burn in the manner described above (a) and (b)  
6.2 Labelling  
The containers shall be securely closed and in addition to the labelling requirements of RS 91 th e following 
information shall be indelibly and legibly marked on the container:  
a) name of the product;  
b) name and full address of the manufacture;  
c) batch number;  
d) date of manufacture and expiry;  
f) quantity in the container ; 
g) active ingredient content,  
h) List of other ingredients used  
i) net mass of content;  
j) directions for use , including indoor or outdoor use ; 
k) safety precaution ;  
©RSB 2018 - All rights reserved                  8 
 l) special population  whose exposure is prohibited (out of reach of children  and pregnant  women) ; and  
m) storage conditions . 
 DRS 393 -2: 2018  
9                ©RSB 2018 - All rights reserved  
 Annex  A 
(normative)  
 
Solvents not permitted for use in aerosols  
1) benzene  
2) 2-butoxyethanol (ethylene glycol monobutyl ether)  
3) 2-butoxyethylacetate (ethylene glycol monobutyl ether acetate)  
4) carbon tetrachloride  
5) chlorobenzene  
6) chloroform  
7) 1,2-dichloroethane (ethylene dichloride)  
8) 2-ethoxyethanol (ethylene glycol monoethyl ether)  
9) 2-ethoxyethylacetate (ethylene glycol monoethyl ether acetate)  
10) n-hexane  
11) 2-hexanone (methyl n -butyl ketone)  
12) 2-methoxyethanol (ethylene glycol monometh yl ether)  
13) 2-methoxyethylacetate (ethylene glycol monomethyl ether acetate)  
14) tetrachloroethylene  
15) trichloroethylene  
16) Propellants  
17) NOTE  The Montreal Protocol and EU 1 Directive on the withdrawal of chlorofluorocarbons (CFCs) 
from aerosols were noted. Hydrocarbon propellants are recommended for insecticide aerosols, 
provided international safety standards are met by the aerosol producer. Industry should be encouraged 
to develop alternative and safer propellants and delivery systems.  
  
©RSB 2018 - All rights reserved                  10 
  DRS 393 -2: 2018  
11                ©RSB 2018 - All rights reserved  
 Annex  B 
(normative)  
 
Dete rmination of pressure in finished aerosol packs  
B.1 Introduction  
The determination of the pressure existing in the finished aerosol packs is necessary to verify that the true 
pressure is compatible with the pressure limitations of the pack, and in accordance w ith the regulations in force.  
True pressure is the relative pressure given by an accurate manometer, at a given temperature.  
B.2 Objective  
The determination of the true pressure in the finished aerosol pack:  
a) in such a way that the measurement affects as little  as possible the value of the real pressure;  
b) in such a way that the manometer will not be polluted by the product under pressure present in the 
pack.  
B.3 Scope  
The method is recommended for determination of the true pressure of all filled aerosol packs.  
B.4 Appa ratus  
The following are required:  
a) a source of reference gas (nitrogen for instance) from which the pressure can be regulated by means 
of a control valve;  
b) a manometer of high accuracy, if possible cushioned by an oil -bath and adapted to fit the aerosol 
container on which the measurement will be effected (Figure 1).  
The apparatus must be assembled in such a way that, in the state of rest, the manometer is connected to the 
reference gas (the pressure of this gas being slightly higher than the actual pressure in the pack) and, for taking 
the measurement, the manometer is connected to the interior of the pack to show the actual pressure.  
B.5 Working operation  
a) Make sure that the aerosol dispenser is thoroughly equilibrated to 30 ± 2ºC.   
©RSB 2018 - All rights reserved                  12 
 b) The measuring apparatus must be fitted with an appropriate adaptor for the valve employed  
c) The pressure of the reference gas must be regulated to a value slightly higher than the anticipated 
pressure of the dispenser.  
d) Apply the measuring apparatus to the valve and press lightly in order to open the valve and the slide of 
the apparatus.  
e) Read the true pressure on the manometer, when the needle has stabilized.  
B.6 Accuracy of measurement  
The measurement of the true pressure will be the more accurate:  
a) with large r aerosol dispenser sizes;  
b) with only a small difference in pressure between the reference gas and the true pressure of the 
dispenser (if required, measurements can be made on additional dispensers after adjusting the 
reference gas pressure to a value very  close to the true pressure);  
c) if the dead volume of the manometer is small (less than 2 ml).  
B.7 Test report  
The test report must indicate, in addition to the results and test conditions, any relevant working details not 
specified in the method, especially i f they are suspected of having influenced the results.  
Note 1  It is necessary to recalibrate the manometer frequently, for example with the aid of a manometric balance.  
Note 2  A non -return valve can be inserted in the apparatus to avoid the aerosol product  penetrating the manometer if 
the pressure of the reference gas is inadvertently much lower than the true pressure in the dispenser.  
 DRS 393 -2: 2018  
13                ©RSB 2018 - All rights reserved  
 Annex  C 
(normative)  
 
Evaluation of discharge rate of filled aerosol dispensers  
C.1 Scope  
The method is applicable to the majority of aerosols marketed at present. It may be used, with discretion, for 
dispenser fitted with vapour -phase taps where there will be a continually changing composition as the contents 
are discharged. It is not suitable for use in the inverted position for dispen sers with vapour phase taps, as there 
will be a erratic discharge dependent upon the liquid content of the dip tube. Where dispensers are intended to 
be used in an inverted position, it is vital that the test shall be done in that way. It is important that  discharge 
tests follow the instructions for use given on the dispenser. The method is not intended for use with metering 
valves.  
C.2 Principle  
The discharge rate of an aerosol dispenser is determined by measuring the quantity of material expelled through 
the valve in the given time. The exact duration of discharge, normally 10 sec, and the temperature of the 
dispenser must be carefully controlled for good reproducibility. Normally the test is repeated three times to give 
three determinations but, in the case o f products filled with vapour phase tap valves, it is preferable to reduce 
the discharge interval to 5 sec and the number of determinations to two. This is to minimise the variation in 
composition that will occur as the contents are sprayed off. There will  be some loss of accuracy using the shorter 
duration of discharge.  
Alternatively, the discharge rate may be determined at different stages in the emptying of the dispenser (e.g. 
90%, 70%, 50%, 30% and 10% fill) which then allows the values to be plotted gr aphically. Where the 
composition changes with the emptying of the packs, this offers a particularly convenient way of showing the 
effect of this change. In the case of storage test samples, a single test is normally performed at each examination 
to conserv e the contents.  
C.3 Apparatus  
A water bath at 25°C ± 0.5°C, a stop watch accurate to 0.2 sec, a balance weighing to 0.1 g and a pressure 
gauge accurate to 2 psig (0.1 kg.cm -2) are required.  
C.4 Procedure  
a) The valve of the aerosol dispenser shall be handled according to label instructions and the 
valve shall be operated for five sec to remove material in the dip tube which may not be 
homogenous with the bulk of the filling.  
 
b) The aerosol dispenser shall be immersed in a water bath maintained at 25°C ± 0.5°C fo r half 
an hour, or for sufficiently long for the contents to attain the temperature of the water bath.  
 
c) The aerosol dispenser shall be removed from the water bath, wiped completely dry, the valve 
operated for one second to remove any water in the valve, th e internal pressures of the 
dispenser shall be measured and the dispenser shall be weighed to within 0.1g.   
©RSB 2018 - All rights reserved                  14 
  
d) The aerosol dispenser shall then be shaken for 3 sec by hand or other suitable means and the 
valve shall be operated fully open for 10 sec, timed b y the stop watch. During the discharge, 
the dispenser shall be positioned as indicated in the instructions for use.  
 
e) The aerosol dispenser shall be wiped clean of any liquid and re -weighed to within 0.1 g.  
Procedures (b) to (d) shall be repeated twice or more and the internal pressure of the dispensers shall be 
measured again.  
C.5 Calculation  
The difference in weights derived from procedure (e) and procedure (c) shall be divided by 10 (sec). Results 
should not differ by more than 0.1 g from the mean of the thr ee results. If a greater difference is found at least 
two more readings should be taken.  
C.6 Reporting  
Report valve discharge rates as g.sec-1at the measured mean pressure of the dispenser. The method, e.g. 3 x 
10 sec, 2 x 5 sec or 1 x 5 sec (90%....50%....10% ) spraying, etc., shall be quoted.  
Notes   
1. Where discharge rates are to be determined at various stages of pack emptying it is advisable to allow 
the pack to reach equilibrium at 25°C in the water bath, shake and spray for 5 sec, re -shake vigorously 
and re -spray for another 5 sec and replace in water bath. This procedure may then be repeated until 
the correct pack content is reached. This rather tedious procedure avoids errors arising from the fall in 
temperature of the contents of the pack during prolonged spraying.  
2. Results may show variations from sample to sample that are greater than might be expected from 
normal manufacturing tolerances. This may be due variations in the valve orifice diameter.  
3. The discharge rate of freshly prepared aerosol dispensers will not normally be the same as for samples 
allowed to ―mature‖ , due to the effect of solvents on the gasket.  DRS 393 -2: 2018  
15                ©RSB 2018 - All rights reserved  
 Annex  D 
(normative)  
 
Testing of valves of filled aerosol dispensers for clogging  
D.1 Apparatus  
a) Fume hood  
b) Protective clothing and mask.  
D.2 Procedure  
Shake the aerosol dispensers thoroughly and, keeping them in an upright position, disperse the contents of 
each into the fume hood. Actuate the valve in a series of cycles (30 sec on, 30 sec off) until the dispenser is 
emptied. Examine the valves for clogging.   
©RSB 2018 - All rights reserved                  16 
 Annex  E 
(normative)  
 
Determination of DEET content  
E.1 General  
The sample is dissolved in carbon disulfide and the difference in absorbance at 14.18 µm and at 14.48 µm is 
determined. The quantity of meta -isomer is obtained from this value by means of a calibration curve p repared 
by the use of a reference standard.  
E.2 Apparatus  
F.2.1 Double -beam infrared spectrophotometer. Perkin -Elmer model 21 or equivalent.  
F.2.2 Two equivalent infrared absorption cells, with sodium chloride windows and a path length of 
approximately 0.4 mm.  
E.3 Preparation of calibration curve  
F.3.1 Weigh (to the nearest 0.1 mg) into four volumetric flasks sufficient amounts of the reference DEET 
standard of known  purity to give concentrations of approximately 20, 40, 60 and 80 g/L when dissolved in carbon 
disulfide. 
F.3.2 Fill the reference cell with carbon disulfide and the sample cell with each of the standard solutions in 
turn, and record the spectra. The spectrum may be scanned rapidly, except for the region 12 – 15 µm, where a 
normal speed should be used. C arry out a blank measurement with carbon disulfide to correct for any inequality 
in the paired cells and to determine whether a cell correction is required.  
F.3.3 Measure the absorbance at 14.18 µm and at 14.48 µm and calculate the difference between these  
value s, ΔA, for each of the solutions. Plot the values of ΔA against the concentration (g/l) of the meta -isomer.  
 
F.3.4 If a cell correction is required, the value of ΔA is determined from the formula:  
 
  ΔA = [A 14.18 – A14.48]ref. - [A14.48]blank 
 
  Where ref. = determination with reference standard  
    blank = determination on CS 2 blank  
 
E.4 Procedure  
Weigh (to the nearest 0.1 mg) about 0.5 g of the sample, transfer quantitatively to a 10 mL volumetric flask, 
and make up to the mark with carbon disulfide. Measure the infrared absorption at 14.18 μm and 14.48 μm 
using the same conditions as described in section A.3. Determine the con centration of meta -isomer by 
comparing this value with the calibration curve. A standard sample should be run each day to check the 
calibration of the instrument.  DRS 393 -2: 2018  
17                ©RSB 2018 - All rights reserved  
 E.5 Calculation  
DEET content (g/kg) =𝐶1 𝑥 𝑃 
𝐶2 
Where,  
 C1 = concentration (g/L) of standard D EET found from calibration curve  
 C2 = concentration (g/L) of sample taken  
 P = purity (g/kg) of the reference standard.   
©RSB 2018 - All rights reserved                  18 
 Annex  F 
(normative)  
 
Determination of permethrin  
Permethrin as one of t he active ingredient s in this product may be determined using HPLC by injecting a solution 
of analyte into a chromatograph, followed by separation and comparison of peak areas of the analyte in the 
sample with that of an external standard.  
F.1 Reagents  
Cis – Permethrin, 99%  
Trans - Permethrin, 99%  
Methanol HPLC grade  
Water, HPLC grade  
F.2 Apparatus  
An HPLC equipped with an autosampler, a variable wavelenght detector (or equivalent) and a column 
(phenomena x, 250 x 4.6mm Luna Phenyl 5μ Reverse phase (or equivalent)  
F.3 Operating conditions  
Flow rate  1.0mL/min  
Solvent composition  60% : 40% (Methanol: Water)  
Elution  Isocratic  
Column temperature  40oC  
Wavelength  240nm  
Injection volume  25 μL  
Stop time  50 minutes  
Post time  2 minutes  
 
F.4 Procedure  
G.4.1Preparation of standard solution  
Weigh about 0.001g (to the nearest 0.0001g) Permethrin standard in beaker, use methanoldissolved and 
transfer them into a separate volumetric flasks (50 ml), dilute to the mark and mix well.  DRS 393 -2: 2018  
19                ©RSB 2018 - All rights reserved  
 G.4.2 Preparation of Solution  
Weigh about 0.02 g (to the nearest 0.0001g) Permethrin test sample into beaker,  use methanol dissolved and 
transfer them into a separate volumetric flasks (50 ml), dilute to the mark and mix well.  
G.4.3 Determination  
After the chromatograph is stable, make a minimum of three injections of the standard as well as for the sample 
and av erage the area counts. The relative standard deviation between injections should be within 2%.  
F.5 Calculation  
The % of either cis or trans isomers is calculated as follows;  
%𝑐𝑖𝑠𝑜𝑟𝑡𝑟𝑎𝑛𝑠𝑝𝑒𝑟𝑚𝑒𝑡 ℎ𝑟𝑖𝑛 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒𝑠𝑎𝑚𝑝𝑙𝑒𝑎𝑟𝑒𝑎 ×𝑤𝑒𝑖𝑔 ℎ𝑡𝑜𝑓𝑠𝑡𝑑 ×𝑝𝑢𝑟𝑖𝑡𝑦 (𝑖𝑛%)
Average  std area  × weight  of sample 
Report the concentration of permethrin as the total of Cis and Trans .  
©RSB 2018 - All rights reserved                  20 
 Annex  G 
(normative)  
 
Flame propagation  
G.1 Principle  
The filled aerosol container is sprayed as a test flame under controlled cond itions and length of the burning spry 
cone is measured.  
G.2 Apparatus  
H.2.1  In its simplest form, the apparatus consists of a base marked at 0.15 m intervals, an adjustable stand 
to carry the aerosol container which may be raised or lowered to accommodate differences in container height, 
a means of measuring the burning spray cone (usually a one metre fuel placed horizontally at the same level 
as the top third of the flame, the hottest part) a means of igniting the spray cone in the form of a test flame 0.0 5 
m ± 0.005 m in height (usually a candle flame is used).  
H.2.2 Water bath maintained at 20 °C .This equipment shall be used to bring the aerosol container and its 
contents to equilibrium at 20 °C (Heat the cans to 20 °C in the water bath) . 
G.3 Procedure  
H.3.1  Place the aerosol container on the stand. Depress the actuator and adjust the height of the stand so 
that the spray cone will pass through the upper third test flame (hottest part).  
H.3.2 Bring the aerosol container and its content to the equilibrium tem perature of 20 °C. Place the 
container on the stand so that the point where the spray emerges is 0.15 m from the test flame. Then light the 
test flame and depress the actuator for 15 seconds to 20 seconds. Record the total length of the burning spray 
cone and specify whether or not it burns back to the actuator.  
 
H.3.3 Extinguish the test flame and record whether the spray cone continues to burn while the actuator is 
depressed.  
 
H.3.4 Repeat each test twice and record the flame length as the average of the three tests.  DRS 393 -2: 2018  
21                ©RSB 2018 - All rights reserved  
 Annex  H 
(normative)  
 
Determination of pH value  
H.1 General  
I.1.1 Reagents  
I.1.1.1  Potassium hydrogen phthalate (COOH -C6H4-COOK) 0.05 mol/l (0.05M)  
Dissolve 10.21 g in freshly boiled distilled water, and make up to 1000 ml. Do not keep the solution for longer 
than one month.  
 
I.1.1.2  Disodium tetraborate (Na 2B4O7.10H 2O 0.05) mol/l (0.05)  
 
Dissolve 19.07 g in freshly boiled and cooled distilled water and make up to 1000 ml. Do not keep the solution 
for longer than one month.  
 
I.1.1.3  Water  
 
Freshly bo iled and cooled distilled water of pH 5.5 to 7.0  
 
I.1.2  Apparatus  
 
I.1.2.1  pH meter  
 
I.1.2.2  Glass electrode and reference electrode  
 
I.1.3 Procedure  
 
Operate the pH meter and electrode system inaccordance with the manufacturer’s instructions . Standardize  
the meter and electrodes with the 0.05 mol/l phthalate (pH 4.00) when an acid solution is being measured or 
0.05 mol/l borate when an alkaline solution is being measured (see table F.1). The reading should not differ by 
more than 0.02 pH units from the or iginal value at which the apparatus was standardized. If the difference is 
greater than 0.05, then repeat the measurements.  
 
Check the pH/mV relationship of the glass electrode daily as follows:  
 
Standardize with the 0.05 mol/l (0.05M) phthalate and measur e the pH of the 0.05 mol/l borate. If the reading 
is higher by 0.02 or more, or lower by 0.05 or more, than the appropriate value in Table F.1, correct the pH 
values of all solutions measured that day, assuming the potential of the glass electrode to be in  a linear 
relationship with the pH of the solution being measured.  
 
Table F.1 – pH values of 0.05 mol/l (0.05M) diosodium tetraborate  
Temperature 
(ºC) 10 15 20 25 30 
pH 9.32 9.28 9.22 9.18 9.14 
Unless otherwise specified, all solutions must be brought to  laboratory temperature before measurement.   
©RSB 2018 - All rights reserved                  22 
 The temperature coefficient of the 0.05 mol/l phthalate can be neglected but that of the 0.05 mol/l borate must 
be taken into account (see table F.1).  
When measuring pH values above 10, use a glass electrode desi gned for use at the alkaline end of the pH 
scale and apply any necessary correction.  
H.2 pH of aqueous dispersions (Method A)  
I.2.1  Reagent  
As for I.1.1  
I.2.2  Apparatus  
As for I.1.2  
Stoppered measuring cylinder 100 ml.  
I.2.3  Procedure  
Weigh 1 g of sample, t ransfer to the measuring cylinder containing water (about 50 ml), make up to 100 ml with 
water, and shake vigorously for 1 min. Allow any suspension to settle for 1 min and then measure the pH of the 
supernatant liquid.  
H.3 pH of aqueous dispersion (Mathod B*)  
I.3.1  Reagents  
As for F.1.1  
I.3.2  Apparatus  
As for I.1.2 together with:  
I.3.2.1  Mixing jar  
A screw cap, glass jar, 295 to 300 ml capacity, substantially cylindrical, approximately 9 cm deep, and without 
abrupt shoulders.  
I.3.2.2  Tumbling machine  
Any mec hanical device for rotating the mixing jar around its centre, end over ent, at 60 rpm.  
I.3.3  Procedure  DRS 393 -2: 2018  
23                ©RSB 2018 - All rights reserved  
 Deposite 8 g (wg) of sample on to distilled water (50 ml) in the mixing jar and allow to stand for 3 min for the 
powder to sink and/or soak undisturbed.  Close the jar and tumble it on the machine at 60 rpm for 5 min. dilute 
with distilled water 9185 ml). tumble as before for 1 min. when the final tumbling is complete, allow the 
suspension to stand for 1 h, then measure the pH of the supernatant liquid by the method given in F.1.   
©RSB 2018 - All rights reserved                  24 
 Bibliography  
[1] ES 757 , Rules Pesticides — Determination of pH value  
[2] Manual on development and use of FAO and WHO specifications for pesticides, November 2010, 2nd 
Edition.  
[3] Official Methods of Analysis of AOAC Internationa l, 19th Edition, 2012, volume I  
 
 DRS 393 -2: 2018  
ICS 65.100  
 
 
©RSB 2018 - All right s reserved