Reference number  
DRS 290: 2016 
© RBS yyyy 
© RSB 2016  
 RWANDA 
STANDARD  DRS 
290 
 
First edition  
2016 -mm-dd 
 
Solid biomass cookstoves  — 
Specifications  
 DRS 290: 2016 
©RSB 2016 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 ascer tain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
 
 
© RSB 2016 
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 photoco pying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to  
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
Tel. +250 252 586103/ 582945  
E-mail: info@rsb.gov.rw   
Website: www.rsb.gov.rw   FDRS 268-1: 2015  
iii                 ©RSB 2016 All rights reserved  
 
 Contents  Page  
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requirements  ................................ ................................ ................................ ................................ .........  3 
5 Emissions, perfor mance and safety requirements  ................................ ................................ ............  3 
6 Fuel ................................ ................................ ................................ ................................ .........................  4 
7 Marking  ................................ ................................ ................................ ................................ ...................  4 
Annex  A (In formative)  General description of ceramic liner cookstove  ................................ .....................  5 
Annex  B (Informative)  Thermal shock/stress resistance  ................................ ................................ ..............  8 
Annex  C (informative)  Water Boiling Test Data Form  ................................ ................................ ...................  9 
Annex  D (informative)  Determination of thermal conductivity of ceramic liner  ................................ ....... 12 
Annex E (informative)  Operating user guide  ................................ ................................ ................................  14 
Annex  F (informative)  Household solid biomass ceramic metal cladded cookstoves dimensions  ....... 15 
 
 
 
 
 
 
 DRS 290: 2016 
©RSB 2016 All rights reserved                  iv 
 
 Foreword  
Rwanda  Standards are prepared by Technical Committees and approved by Rwanda 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 st andards.  
The main task of technical committees is to prepare national standards. Final Draft Rwanda Standards 
adopted by Technical committees are ratified by members of RSB Board of Directors for publication and 
gazettment as Rwanda Standards.  
This standar d replaces  RS 165 -1 Biomass stoves - Specifications - Part 1: Household charcoal cook stoves  
 
DRS 290  was prepared by Technical Committee RSB/TC 23, Mechanical engineering and metallurgy . 
 
In the preparation of this standard, reference was made to the follo wing standards:  
 
1) KS 1814 -1:2005;  Biomass stoves — Performance requirements and test methods — Part 1: Household 
biomass stoves  
2) US 761:2007; Energy efficiency stoves  — Household biomass stoves — Performance requirements and 
test methods  
3) Rwanda Impr oved Canamake (RIC) Stove Standard Document  
 
The assistance delivered from the above source is hereby acknowledged with thanks.  
 
 
Committee membership  
 
The following organizations were represented on the Technical Committee on Mechanical engineering and 
metallurgy (RSB/TC 023) in the preparation of this standard.  
 
ABEM Engineering and Manufacturing  
Chillington Rwanda  
ENEDOM  
Del Agua  
Integrated Polytechnic Regional Cent re - Kigali  (IPRC)  
Tumba College of Technology (TCT)  
IB & C  
Master Steel  
Nikil and Consult ant 
Rwanda Agriculture Board (RAB)  
Rwanda Environment Management Authority (REMA)  
Rwanda Utilities Regulatory Authority  
REG/EDCL  
SAFINTRA  Rwanda Ltd  
COPEDU  
SNV Rwanda  
Rwanda Natural Resources Authority (RNRA)  
Practical action Rwanda  
IPRC Tumba College of T echnology  FDRS 268-1: 2015  
v                 ©RSB 2016 All rights reserved  
 
 Inyenyeri Ltd  
UR-CAVM  
REG  
Ruliba Clays Ltd  
UR-CST 
TKEA  
Rwanda  Standards Board  (RSB) – Secretariat  
 
 
 
 
 
 
 DRS 290: 2016 
©RSB 2016 All rights reserved                  vi 
 
 INTRODUCTION  
This Rwanda standard is intended for use to set performance requirements for cookstoves used primarily for 
cooking or water heat ing. Its purpose is to  help producers and users to reduce the detrimental impact on 
environment and health of traditional cooking practices  with the view to improve livelihood of citizens.  The 
additional general description of  ceramic liner cookstove is provided in Annex A  as informative information to 
help local producers in manufacturing process . 
This standard was developed to improve the quality of cookstoves on the market  and was developed from 
best practices from existing cookstove s available on market  which comply with minimum technical conditions 
as set by ISO and regional standards . 
 DRS 290: 2016 
1                 ©RSB 2016 All rights reserved  
 
 Solid biomass cookstoves  — Specifications   
1 Scope  
This Draft Rwanda Standard specifies the requirements and test methods for solid biomass cook stoves.  The 
standard is a pplicable to  cookstoves used primarily for domestic and small -scale institutional cooking or water 
heating  excluding stoves used primarily for space heating . 
2 Normative  references  
The following referenced documents are indispensable for the application of t his document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
ISO19867 -1 (under development), Clean cookstoves and clean cooking solutions — Harmonized laboratory 
test protocols — Standard Test Sequence for emissions and performance, safety, and durability  
ISO19867 -2 (under development), Clean cookstoves and clean cooking solutions — Harmonized laboratory 
test protocols  — Contextual test sequences  for emissions and performance  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply . 
3.1   
Cookstove  
  
apparatus  which is used to cook food and/or provide warmth and/or boil water through the conversion of 
biom ass, typically through combustion  
 
3.2   
biomass   
material of biological origin excluding embedded in geological formations and/or fossilized.  
 
3.3 
cooking vessel  
 pot or container fabricated of heat -resistant material in which food or water is heated and  prepared  
 
3.4 
maximum cooking power  
highest cooking power for which a cookstove is designed, in kW  
 
3.5 
minimum cooking power  
lowest cooking power  for which a cookstove is designed, in kW  
 
3.6   
©RSB 2016 All rights reserved                  2 
 
 organic carbon  
carbonaceous material in which the carbon is c hemically bonded to hydrogen and possibly also oxygen,  
nitrogen, sulphur or other elements  
 
3.7 
particulate matter  
solids and liquids of a sufficiently small size to be suspended in air  
 
3.8 
 PM 10 
particulate matter such that the aerodynamic diameter of th e particles is less than or equal to 10  m 
 
3.9 
 PM 2.5 
fine particulate matter such that the aerodynamic diameter of the particles is less than or equal to  2.5 m 
3.10 
combustion  efficiency   
proportion of latent heat in a fuel transferred as heat  to a working fluid (water)  
3.11  
thermal effici ency  
ratio of useful energy delivered to fuel energy used  
3.12 
Water Boiling  Test  
A test in which the performance of a stove is evaluated through the heating of a known quantity of water 
across a specified range of temperature following a defined protoco l  
3.13 
black carbon (BC)  
particulate carbonaceous material, typically the product of combustion that comprises primarily carbon  
3.14 
durability  
ability of a cookstove to continue to be operated for an extended period safely and with minimal loss of 
perfo rmance under conditions typical of those found in the target community  
3.15 
safety   
ability of a cookstove  to be operated  at an acceptable level of risk of harm  
 
3.16  
field testing  
measurement of cookstove  performance conducted in the target community under typical  operating 
conditions  DRS 290: 2016 
3                 ©RSB 2016 All rights reserved  
 
 4 Requirements  
4.1 General requirements  
4.1.1  All component parts of solid biomass cook  stoves shall be made of non corroding material or 
protected against corrosion by a suitable anticorrosion coating.  
4.1.2  The solid biom ass cook  stoves shall use improved technologies to yield low emissions and high 
level of efficiency, durability and safety.  
4.1.3  The solid biomass cook stoves shall be evaluated based on performance in the areas of fuel 
efficiency, emissions of fine parti culate matter (PM 2.5) and carbon monoxide (CO), indoor emissions 
(particulate matter 2.5 and carbon monoxide),black carbon content, durability and safety and each area shall 
be ranked separately.  
4.1.4  The cookstove shall be supplied with user guide in  one of three official languages  used in Rwanda  
5  Emissions , performance  and safety requirements  
5.1 Emissions shall be measured for the qualitative and quantitative determination of pollutant -emitting 
sources to ensure that the pollution is within acceptable  limits  as given in table 1. 
5.2 Cookstove performance  (thermal efficiency and durability)  and safety requirements  shall be within the 
limits given in table 1  
Note The standard ISO 19867 is still under development . 
Table 1 -  Cookstoves performance  
Type of  
stoves  Thermal 
efficiency 
(%) PM 2.5 
(mg/MJd)  CO 
(g/MJD)  BC 
(mg/MJD)  Safety 
(score)  Durability 
(score)  Test protocol  
Best ≥45 ≤38 ≤8 ≤6 ≥95 <10 ISO 19867 -1 
or ISO 
19867 -2 
Better  ≥35 ≤137  ≤11 ≤21 ≥88 <15 ISO 19867 -1 
or ISO 
19867 -2 
Good  ≥25 ≤513  ≤16 ≤77 ≥75 <20 ISO 19867 -1 
or ISO 
19867 -2 
Note The test protocol done depending on the purpose (for general comparison, use ISO 19867 -1 and for contextual sequence use ISO 19867 -2) 
5.3  Instruments used for measuring gaseous pollutant concentrations shall be ca librated at the beginning 
and end of each day of testing with certified calibration  gases. Calibrations shall be documented.  
5.4 All cookstoves shall be at least be classified in one of the three categories given in table 1.   
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5.5  After testing, the test r eport shall indicate the category of the tested coo kstoves as given in table 1.  
6  Fuel 
The solid biomass fuel shall comply with the relevant national, regional or international standards.  
7 Marking  
All solid biomass cook stoves shall be indelibly and legibly marked with the following information in at least one 
of the three official languages used in Rwanda  and shall be placed in a clear location on the cookstove : 
a) manufacturer’s name or trade mark and address;  
b) name of product;  
c) production date;  
d) cooking therma l efficiency  at maximum power ;  
e) maximum cooking power;  
f) standard number;  
g) weight of the cookstove and  
h) maximum weight  that the stove can withstand  
The marking shall be done either by painting or by using tags  
 
 DRS 290: 2016 
5                 ©RSB 2016 All rights reserved  
 
 Annex  A 
(Informative)  
 
General description of  ceramic liner cookstove  
A.1 General requirements  
A.1.1   The portable ceramic liner cookstoves shall consist of a fired ceramic liner cladded in a 
metal sheet surround using an acceptable insulation material, suitable pot rests, grate and stove 
stands . 
A.1.2   The fixed ceramic liner cookstoves shall consist of a fired ceramic liner properly integrated in 
the mud hearth with acceptable insulation material, suitable pot rests, grate in adequate wood inlet 
and combustion chamber.  
A.1.3   The improved cookstoves shall use improved technologies  with environmental friendly 
materials to yield low emissions and high level of efficiency, durability and safety.  
A.2 Material requirements for fixed and portable ceramic cookstoves  
A.2.1  Cladding  
The cladding materials used in the manufacture of household solid b iomass ceramic metal cladded stoves 
shall be steel  material  sheet with a minimum thickness of 0.63 mm (Gauge 22).  
A.2.2  Clay  
Suitable clay shall withstand firing temperature of up to 1 000oC. Proportions of sand to clay shall be at least 
3:7 (30% and 70%) in rat ios respectively.  
A.2.3  Clay testing  
Tests shall include coiling and sedimentation.  
A.2.4  Coiling test  
The test shall be performed to determine the clay to sand ratio. It is done by taking a piece of clay and rolling 
to make a strip between two hands and then coiling.  
A small lump is kneaded into a long strip that is drawn out into an arc or it makes a semi circle without 
breaking or cracking and therefore it is suitable.   
©RSB 2016 All rights reserved                  6 
 
 A.2.5  Sedimentation test  
Take a lump of clay and stir in water in 1:1 ratio. Put it in a transparent con tainer and leave it to settle. Clay 
should settle on top and sand to the bottom. Sand goes to the bottom, then soil and water.  
A.3  Ceramic liner  
A.3.1  The ceramic liner shall be made from suitable pottery clay that has been fired as specified in 
4.2.2  
A.3.2  The ceramic liner shall be properly fired and shall not have a black core.  
A.3.3  A properly fired liner produces a sharp high pitch tone sound  when tapped with a finger or a 
stick while an under fired liner sound dull.  
A.3.4  The ceramic liners shall not crack due to heating and cooling cycles developed due to 
thermal stress. A ceramic liner made with a clay mix which is thermal shock resistance shall be able 
to withstand 5 cycles when tested in accordance with the procedure specified in Annex B.   
A.3.5  A ceramic liner shall have its t hermal conductivity value not exceeding 2, 5 WK -1m-1 at 
500°C when determined in accordance with the procedure specified in Annex D. 
A.4 Pot rests   
A.4.1   Pot rests for portable ceramic cookstoves shall be made from mild or twisted steel bars 
minimum diameter of 8 mm and shall be fixed at the top of the metal cladding during assembling.   
A.4.2   Pot  rests for fixed ceramic cookstoves shall be made from clay moulded  and attached to 
the upper part of the ceramic liner .  
A.4.3   Pot rests for complete ceramic stoves shall be of same material.  
A.5  Insulation  
The insulation between the cladding material and ceramic liner shall be made of various mixtures of material 
as described in Table 1.  
Table 1 — Material composition of insulation  
Material  Ratio (Volume)  
 
Cement :sand: rice husks  1:½:4  
 Cement :sand: lime  1:1:2  
Cement: lime: kaolin  1:1:2  DRS 290: 2016 
7                 ©RSB 2016 All rights reserved  
 
  Cement :sand :wood ash  1:½ :3  
Cement: Vermiculite  1:3 
Cement :Diatomite  1:3 
Cement: Sand:  ash 2:1:6  
Note  Any other insulation  materials may be used provided that they meet the 
requirement s of thermal conductivity tests (see Annex D)  
 
A.6 Assembling the complete stove  
A.6.1   The cookstove shall be assembled in such way that it can withstand the weight of the pot 
while cooking.  
A.6.2   All component parts of the portable cookstoves and improved cookstoves s hall be made of 
non corroding material or protected against corrosion by a suitable anticorrosion coating.  
A.6.3   The household solid biomass cookstove and its component parts shall be smooth and free 
from defects that adversely affect the appearance, performan ce and safety aspects during use such 
as cracks, sharp edges or burrs.  
A.6.4  A grate shall be designed in such way that it can hold the burning solid biomass, evacuate ash 
and facilitate circulation of sufficient air through the burning solid biomass  
A.6.5  The stove stands shall be designed in such way that it can maintain the stability of the entire 
cookstove while cooking and shall be non combustible material.  
 
 
 
 
 
 
 
 
  
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 Annex  B 
(Informative)  
 
Thermal shock/stress resistance  
B.1 To test whether ceramic liners made from particula r clay mix are thermal shock 
resistant, the liners  shall be heated to  temperature ranging 800 °C – 900 °C and then 
immersed in cold water at room temperature.  These temperatures are attained in fireboxes 
when in use.  This is repeated several times unti l the liner cracks. The heating can be done 
using a gas flame or an electric kiln.  
B.2 As the test is extremely severe, a liner which can withstand 5 cycles shall be 
considered to be made from a clay mix that is thermal shock resistant  
 
 
 
 
 
 
 
 
 
 
 
 
 
 DRS 290: 2016 
9                 ©RSB 2016 All rights reserved  
 
 Annex  C 
 
(informa tive) 
 
Water Boiling Test Data Form  
  
©RSB 2016 All rights reserved                  10 
 
 
 DRS 290: 2016 
11                 ©RSB 2016 All rights reserved  
 
 
  
©RSB 2016 All rights reserved                  12 
 
 Annex  D 
(informative)  
 
Determination of thermal conductivity of ceramic liner  
For determination of thermal conductivity of ceramic liner, a specimen measuring 80 mm x 30 mm x 10 mm 
shall be cut from the ceramic liner whos e thermal conductivity is to be determined.  
The reference material measuring 80 mm x 30 mm x 10 mm shall be of hard fibre glass board, whose thermal 
conductivity is known.   
D.1 Procedure  
D.1.1   The Transient hot wire method of comparison shall be employed.  
D.1.2   The hot  wire is sandwiched between a plate -type experimental specimen and a reference 
specimen whose value of thermal conductivity is known.  
D.1.3   The specimen to be tested is cut into a plate type experimental specimen just the same 
shape and size as the reference sp ecimen of fibreglass board.  
D.1.4   Both the specimen and reference material are pressed by loading to come into close contact 
with each other.  
D.1.5   At the centre of the hot wire, a thermocouple is installed by means of spot welding.  
D.1.6   Care should be taken so that the  thermocouple wires have no gap between them because a 
gap at the junction will lead to the voltage due to the current of the hot wire to be added (or 
subtracted) to the electro  
D.1.7   The thermocouple wires are fitted directly to thermocouple thermometer, which  reads in ºC.  
The specimens are placed inside a furnace so that the temperature at which the thermal 
conductivities are measured may be varied.  
Table D .1 Calculations -Report of results -Thermal conductivity test -Data form  
Oven 
temperature  Thermal conductiv ity  WK-1m-1   
1 2 3 4 5 Mean Value  
200       
400       
600       
800       DRS 290: 2016 
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 1000         
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 Annex  E 
(informative)  
 
Operating user guide  
Every biomass stove supplied shall contain operating user guide as illustrated in table E1 below for its safe 
and efficient use. 
Table E 1− Operating user guide for solid biomass cook stoves  
Dos  Don’ts  
Load the stove with solid biomass that has 
already been broken down to convenient size  Do not break large pieces of solid biomass 
inside the stove  
Make sure the air gate is o pen while lighting  Do not light the stove with paraffin or any 
petroleum oils, as this will damage the liner  
Light using waste paper or twigs on one side of 
the solid biomass  Do not pour water in the stove to extinguish fire  
Close the air gate for simmer ing of foods once 
they come to boil, this will help to save the fuel 
you are using  Don’t shake the stove to add solid biomass  
when necessary  
Remove ash by hand through the air gate  Don’t remove ash by shaking the stove  
Pass a piece of stick through the hot solid 
biomass to push ash into the ash box and add 
solid biomass  Don’t pass a piece of plastic stick  through the 
hot solid biomass to push ash into the ash box 
or  add solid biomass  
Use a piece of stick to push the remaining solid 
biomass out of the s tove then pour water  Don’t invert the stove to remove the remaining 
solid biomass  
NOTE Cleaning the stove surface after use will make the stove to be more appealing for further 
use, but make sure that the stove should be getting cool if you are using you use wet fabrics to 
clean and don’t leave the stove in the rain.  DRS 290: 2016 
15                 ©RSB 2016 All rights reserved  
 
 Annex  F 
(informative)  
 
Household solid biomass ceramic metal cladded cookstoves dimensions  
Table F.1 —Household solid biomass ceramic metal cladded cookstoves dimensions in millimeters  
Stove parts  Size 
Designation  Small  Medium  Large  
 
Bottom and top diameter of 
cladding  A 250-260 280-290 300 
Overall height  h 200 220 ±10  230 
Top inside diameter of liner  C 205 230 240 
Base inside diameter of liner  D 150 165 175 
Fire box depth  E 70 75 90 
Ash box depth  F 60 90 90 
Grate diameter  D 150 165 175 
Grate thickness  tc 20 20 20 
Grate hole diameter  J 20 20 20 
Inlet air door  K 80 x 120  100 x 130  100 x 130  
Thickness of ceramic liner  L 20 20 20 
Thickness for insulation  M 15 15 15  
©RSB 2016 All rights reserved                  16 
 
 Figure E .1 - Top view of stove  
 
Figure E .1 - Top view of stove  
 
 
 
 
DRS 290: 2016 
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 Figure E 2 Cross sectional view of the solid biomass stove (view x -x) 
 
DRS 290: 2016  
ICS 65.060.01  
 
 
©RSB 2015  All right s reserved