FINAL DRAFT UGANDA 
STANDARD  FDUS 854-1
First Edition
2009-mm-dd
 
Reference numbe  
r
FDUS 854-1: 2009
   
  ©UNBS 2009 
  
Thermal solar systems and components - Solar collectors – 
Part 1: General requirements  
 FDUS 854-1: 2009 
ii © UNBS 2009– All rights reserved
 Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS  2009  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, in cluding photocopying and microfilm, without prior written 
permission from UNBS. 
Requests for permission to reproduce this document should be addressed to 
The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
Kampala  
Uganda 
Tel: 256 414 505995 
Fax: 256 41 286 123 
E-mail: unbs@infocm.co.ug 
Web: www.unbs.go.ug FDUS 854-1: 2009 
© UNBS 2009 – All rights reserved  iii
 Contents Page 
Foreword ............................................................................................................................................................iv  
1 Scope ......................................................................................................................................................1  
2 Normative references ............................................................................................................................1  
3 Terms and definitions ...........................................................................................................................1  
4 Symbols and units .................................................................................................................................1  
5 Durability and reliability ........................................................................................................................1  
5.1 Materials and design .............................................................................................................................1  
5.2 Required tests ........................................................................................................................................2  
5.3 Pass criteria ...........................................................................................................................................2  
5.4 Procedure ...............................................................................................................................................4  
6 Safety ......................................................................................................................................................4  
7 Collector identification..........................................................................................................................4  
7.1 Drawings and data sheet ......................................................................................................................4  
7.2 Labelling .................................................................................................................................................4  
7.3 Installer instruction manual .................................................................................................................5  
Annex A (informative)  Description of solar collectors materials and manufacture ...................................6  
A.1  General ..................................................................................................................................................6  
A.2  Absorbers ..............................................................................................................................................6  
Annex B (informative)  Environmental protection ..........................................................................................8  
Annex C (informative)  Tests to be rep eated in collector design modifications .........................................9  
Bibliography ............................................................................................................................... .......................10  
 
 FDUS 854-1: 2009 
iv © UNBS 2009– All rights reserved
 Foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 323, of the Laws of Uganda.  UNBS is mandated to co-ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
Committee membership 
The following organisations were represented on Subcommittee on Solar Energy, UNBS TC 13/SC 3, in the preparation of this standard: 
• Renewable Energy Department, Minist ry of Energy and Mineral Development 
• Makerere University 
• Incafex Solar Systems 
• Battery Masters (U) Limited 
• Equator-sun (U) Limited 
• Ultratec (U) Limited 
• Sonnerkraft Solar Systems 
• Solar Masters 
• Uganda National Plumbers Association 
• Uganda Institute of Professional Engineers 
• Uganda National Bureau of Standards 
 
 FINAL DRAFT UGANDA STANDARD FDUS 854-1: 2009
 
© UNBS rved 1
 2009 – All rights reseThermal solar systems and components – Solar collectors – 
Part 1: General requirements 
1 Scope 
This Uganda Standard specifies requirements on durability (including mechanical strength), reliability and 
safety for liquid heating solar coll ectors. It also includes provisions for evaluation of conformity to these 
requirements. 
It is not applicable to those collectors in which the thermal storage unit is an integral part of the collector to such an extent that the collection pr ocess cannot be separated from the storage process for the purpose of 
making measurements of these two processes. It is not  applicable to tracking concentrating solar collectors. 
Collectors that are custom-built (built-in, roof integrated colle ctors that do not comprise factory made modules 
and are assembled directly on the place of installation) cannot be test ed in their actual form for durability, 
reliability and thermal performance according to this st andard. Instead, a module with the same structure as 
the ready collector is tested. The module gross area in t he case of custom built colle ctors should be at least 2 
m2. The test is valid only for larger collectors, than the tested module. 
2  Normative references 
The following referenced documents are indispensable fo r the application of this Uganda Standard. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any requirements) applies. 
US 854 -2, Thermal solar systems and components – solar collectors – Part 2: Test methods 
ISO 9488, Solar energy – Vocabulary 
3  Terms and definitions 
For the purposes of this Uganda Standard, the terms and definitions given in ISO 9488 apply. 
4  Symbols and units 
For the purposes of this Uganda Standard, the sym bols and units given in ISO 9488 and DUS 854 -2 apply. 
5  Durability and reliability 
5.1  Materials and design 
Information about the materials and manufacture of solar collectors, including the materials they are 
manufactured of and their resistance to all influences which they might meet in service, retaining their 
operational ability are given in Annex A. FDUS 854-1: 2009 
2 © UNBS 2009 – All rights reserved
 5.2  Required tests 
The collector shall be subjected to the following series of tests: 
a) Internal pressure for absorber (see 5.2 of DUS 854 -2); 
b) High temperature resistance  (see 5.3 of DUS 854-2); 
c) Exposure (se 5.4 of DUS 854-2); 
d) External thermal shock. May be combined with the high temperature resistance or exposure test (see 
5.5 of DUS 854-2); 
e) Internal thermal shock. May be combined with the high temperature resistance or exposure test (see 
5.6 of DUS 854-2); 
f) Rain penetration, only for glazed collectors (see 5.7 of DUS 854-2); 
g) Mechanical load (see 5.9 of DUS 854-2); 
h) Thermal performance (see  Clause 6 of DUS 854-2); 
i) Freeze resistance, only in the ca ses specified in 5.8 of DUS 854-2; 
j) Stagnation temperature (see Annex C of DUS 854- 2). May be combined with the high temperature 
resistance or exposure test. 
k) Final inspection (see 5.11 of DUS 854-2). 
The optional test for impact resistance (see 5.10 of DUS  854-2) shall be carried out if requested. The result 
shall be recorded. 
NOTE Regarding the durability and reliability of elastic materials it is recommended to refer to ISO 9808 and ISO 9553. 
5.3     Pass criteria 
5.3.1 General 
The pass criteria for the reliability te sts are given for each test in 5.3.2 to 5.3.10. The term “no major failure”, 
denotes that none of the following occurs: 
- Absorber leakage or such deformation that permanent contact between absorber and cover is 
established; 
- Breaking or permanent deformation of cover or cover fixing; 
- Breaking or permanent deformation of collector fixing points or collector box; 
- Vacuum loss, such that vacuum or sub-atmospher ic collectors shall be classified according to the 
definition in ISO 9488 (only applicable for va cuum and sub-atmospheric collectors); 
- Accumulation of humidity in form of condensate on th e inside of the transparent cover of the collector 
exceeding 10 % of the aperture area. 
NOTE The evaluation of accumulation of humidity for applicat ion of the pass criteria should be applied only on the 
following tests: 
- external Thermal shock FDUS 854-1: 2009 
© UNBS 2009 – All rights reserved  3
 - rain penetration test 
5.3.2 Internal pressure for absorber 
The test pressure shall be as specified in 5.2 of DUS 854-2. In the case of absorbers made of organic 
materials, climate conditions according to Table 2 of DUS  854-2 shall be applied. After the internal pressure 
test, the collector shall not show any major failure as defined in 5.3.1. 
5.3.3 High temperature resistance 
When tested in accordance with 5.3 of DUS 854-2, the co llector shall not show any major failure as defined in 
5.3.1. 
5.3.4 Exposure 
When tested in accordance with 5.4 of DUS 854-2, the collector shall not show any major failure according to 
5.3.1 and none of each potential problems of their comp onents shall be graded 2 on the scale given in B.5.5 
of DUS 854-2. 
5.3.5 External thermal shock 
When tested in accordance with 5.5 of DUS 854-2, the co llector shall not show any major failure as defined in 
5.3.1 
5.3.6 Internal thermal shock 
When tested in accordance with 5.6 of DUS 854-2, the co llector shall not show any major failure as defined in 
5.3.1. 
5.3.7 Rain penetration 
NOTE This test is applicable only for glazed collectors 
A visual check shall not show water trace. Moreover, at least one of the following shall be fulfilled: 
a)  by weighing the collector the determi ned water quantity shall be less than 30 g/m2 or 
b) by measuring the humidity inside the collector, any visible droplets inside the collector or humidity that 
exceeds 20 g/kg at any time during the test or humidity that doubles from the value measured after 
stabilization shall yields to “major failure” or 
c) measured condensation level shall be less than 10 % of the transparent cover and the quantity of the 
water that comes out of the collector  when tipping it shall be less than 30 g/m2. 
5.3.8 Mechanical load test 
When tested in accordance with 5.9 of DUS 854-2 the cover, the collector box and the fixings between 
collector box and mounting system shall not show any ma jor failure as defined in 5.3.1 and 5.9.1.3 of DUS 
854-2. The permissible and the maximum positive and n egative pressure shall be recorded in the installer 
manual . 
5.3.9 Thermal performance 
When tested in accordance with Clause 6 of DUS 854-2, the collector shall not show any major failure as 
defined in 5.3.1. Thermal performance shall be reported. 
5.3.10 Freeze resistance test FDUS 854-1: 2009 
4 © UNBS 2009 – All rights reserved
 This test shall be carried out only in the cases specified in 5.8.1 of DUS 854-2. The pass criterion is no major 
failure as defined in 5.3.1 after three freeze-thaw cycles. 
5.4  Procedure 
The required number of collectors shall be available for testing. The collector s shall be tested in accordance 
with 5.2. The collectors conform to this standard, only if a ll pass criteria are fulfilled. Freeze resistance shall be 
tested, for collectors which the manufacturer claims  can withstand freezing and freeze/thaw cycling and which 
are not intended to be filled with antifreeze fluids.  
6  Safety 
The maximum fluid temperature to be considered in the design of a solar collector or solar plant is the 
collector stagnation temperature. Materials to be used  in the manufacture of collectors or installations 
incorporating the collector (expansion tanks, safety valves, etc.) shall be chosen taking into account this 
temperature. 
The stagnation temperature shall be calculated in accordance with Equation C.1 of DUS 854-2 under the following climate parameters: 
-  Hemispherical irradiance on collector plane 1000 W/m2; 
-  Surrounding air temperature 30 °C. 
Stagnation temperature (see Annex C of DUS 854-2) may be combined with the high temperature resistance 
or exposure test. 
The collector shall provide for safe installation and  mounting. Sharp edges, loose connections and other 
potentially dangerous features shall be avoided. If the weight of the empty collector exceeds 60 kg, an 
anchorage for a lifting device shall be included, except  for the collectors that are assembled on the roof. 
Collectors filled with a heat transfer fluid irritant to human skin or eyes, or toxic, shall carry a warning label. 
7    Collector identification 
7.1  Drawings and data sheet 
The collector submitted for test shall be accompanied by a set of drawings describing the collector's 
dimensions and structure along with a list of materials used in the collector and important physical and optical 
properties as well as by the solar collector descripti on in D.2 or E.2 of DUS 854-2. Drawings shall have a 
number, date of issue and possible revi sion date. These documents shall be filled by the test institute for at 
least the period of time that the collect or type is traded by the manufacturer. 
NOTE  The manufacturer is usually obliged to keep these drawings for at least th e period of time that the warranty of 
the collector type is valid. 
7.2  Labelling 
Collectors shall carry a visible and durable label with the following data: 
- Name of manufacturer; 
- Type; 
- Serial number; 
- Year of production; 
- Gross area of collector; FDUS 854-1: 2009 
© UNBS 2009 – All rights reserved  5
 - Dimensions of collector; 
- Maximum operation pressure; 
- Stagnation temperature at 1000 W/m2 and 30 oC; 
- Volume of heat transfer fluid; 
- Weight of empty collector…………………………………… Made in: …………………………….. 
 7.3  Installer instruction manual 
Solar collectors shall be accompanied by an installer inst ruction manual, if traded as stand-alone components.  
When they are part of a complete sy stem, the system installation manual can cover the complete system. In 
that case no separate manual for the collector shall be required. The instruction manual shall at least contain 
the following information: 
-  dimensions and weight of the collector, instruct ions about the transport and handling of the collector; 
-  description of the mounting procedure; 
-  recommendations about lightning protection; 
-  instructions about the coupling of the collectors to one another and the connection of the collector field to 
the heat transfer circuit, including dimensions of pipe connections for collector arrays up to 20 m2; 
- recommendations about the heat transfer media which may be used (also with respect to corrosion) and 
precautions to be taken during filling, operation and service; 
-  maximum operation pressure, the pressure drop and the maximum and minimum tilt angle; 
-  permissible wind and snow load; 
-  maintenance requirements. 
If the collector is traded as a component and sold directly  to customers, all relevant documentation concerning 
personal safety, maintenance and handling of the produc t shall be made available to the customer in the 
national language of the country where it is sold. 
 
 FDUS 854-1: 2009 
6 © UNBS 2009 – All rights reserved
 Annex A 
(informative)  
 
Description of solar collector s materials and manufacture 
A.1  General 
The operational ability and long lifetime of solar co llectors depend on the correct choice of appropriate 
materials. Testing of the materials, including accelerat ed life testing, is very important for the development of 
new collectors and the prediction of service life. Respective literature is referred to in the Bibliography. 
Solar collectors may be affected by airborne fire or radiant heat. The use of non-combustible materials should 
be preferred. Collectors should comply with  the regulations to fire-classification. 
The collector box should be water-tight to prevent penet ration of rain water. The collector box should be 
constructed in such a way that condensed water does not accumulate in the collector, as this might impair its 
functional capability and durability. For that purpose t he collector should be properly designed to enable 
ventilation of air through the collector box. 
The construction of the collector should ensure that no undue stress is built up in the cover, even at the 
maximum stagnation temperature of the collector. The materials of collector components should be selected 
and constructed so that they can withstand the ma ximum temperature which may occur at stagnation 
conditions and the thermal shocks they may be expose d to during the summer period. The materials of the 
collector should preferably be resistant  to exposure to UV-radiation and in cases where materials selected are 
not so, they should be protected against incident and reflected UV-radiation. 
Bushings and ducts, leading through the box, should be constructed so that no leakage can occur caused by thermal expansion. The collector box bushings should withstand any damage,  if they have to be soldered for 
assembly. The design of collector should be such t hat heat bridges between the collector box and the 
absorber are avoided. 
The components and the materials of the collector shoul d be able to withstand the mechanical loads resulting 
from the heating up and cooling down of the collector. They should also be resistant to environmental stress from outdoor climate caused by factors such as ra in, snow, hail, wind, high humidity and air pollutants. 
A.2  Absorbers 
Absorbers should be made from suitable materials to cope with mechanical, thermal and chemical 
requirements of the application. The effect of the manufa cturing processes like cutting, brazing, soldering etc., 
on the properties of the absorber, should be considered. 
The absorber ducts which guide the flow of the heat transfer fluid, including the connection lines, should be designed and constructed in such a way that venting c an be effected in the installed condition, thus ensuring 
the functional capability of the collector. 
Absorbers should be dimensioned on the basis of a calculation pressure corresponding to the permissible working overpressure specified by the manufacturer taki ng into consideration a safety factor of 1.5. The 
properties of the heat transfer medium should be considered as well. 
The effect of the maximum temperature (stagnation temper ature) of the absorber should be considered in the 
selection of material. 
In the case of materials with strengt h characteristics, which vary apprecia bly with the temperature and/or UV-
exposure, the evaluation criteria should be determined individually in each case. 
 FDUS 854-1: 2009 
© UNBS 2009 – All rights reserved  7
 The wetted side of the absorber should withstand corros ion under normal operating conditions and taking into 
account the admixture of possible additives to the heat transfer fluid. The walls of swimming pool collectors 
which are wetted by the swimming pool water should be re sistant to the additives used for the treatment of the 
swimming pool water. 
Absorber coatings should retain their optical properties under high temperature, high humidity and 
condensation, and sulfur dioxide at high humidity. 
A.3  Transparent covers 
Solar collectors are generally covere d with glass or transparent plastic glazing. The durability of glass and 
tempered glass under the service conditions found in solar collectors is  good, but the resistance of plastics 
and glass treated with a special coat ing to the combined effects of UV radiation and temperature may be poor. 
There may be significant degradation with time, and in  the case of a reduced transmission in the solar 
wavelengths, this will lead to degradation in collector performance. A reduction in the tensile strength or 
impact strength of a cover material may lead to a failure of the collector cover. 
The transparency of the covers should not deteriorate ap preciably during the service life of the collector, the 
covers should be resistant to ultraviolet (UV) radiation, air pollution, high humidity and condensate as well as 
high temperatures depending on the collector design. 
A.4  Insulation materials 
Insulation materials should withstand the local temperature arising during stagnati on temperature conditions of 
the collector. At this temperature no melting, shrinkage or outgasing of the insulation with consequent condensation inside the collector cover,  or absorber performance  reduction or corrosio n of metallic surfaces 
should occur to the extent of seriou sly reducing the collector performance. 
Water or humidity absorption by the insulation mate rial may shortly or permanently reduce the insulation 
performance of the material. 
Thermal expansion of the material used in the collec tor due to the wide range of temperatures should be 
taken into consideration because of different ther mal expansion coefficients. Furthermore transparent 
insulation materials or Teflon layers used should not det eriorate appreciably, both mechanically and optically, 
during the service life of the collector due to ultrav iolet (UV) radiation, high temperature and humidity. 
A.5  Reflectors 
Reflectors, diffuse or specular, are re flecting surfaces used to increase t he radiation, incident on the absorber. 
The reflecting surface should be resistant to environment al influences such as air pollution and to corrosion 
through humidity or rain. Outside the collector box reflectors should also resist mechanical loads through wind, snow and hail, whereas inside reflectors should withstand high temperatures. 
A.6  Diffusion barriers 
Diffusion barriers are materials used between absorbers and insulation material to prevent diffusion into or out of the insulation material. They should be able to wi thstand the absorber high temperatures and the incident 
UV radiation without shrinking and the high humidit y or condensate accumulated remaining tight. 
 FDUS 854-1: 2009 
8 © UNBS 2009 – All rights reserved
 Annex B  
(informative) 
 
Environmental protection 
B.1  Heat transfer fluid 
The heat transfer fluid used should not be toxic, seriously irritant to the human skin or eyes, or water polluting 
and it should be fully biodegradable. 
B.2  Insulation materials 
For the collector insulation no materials should be us ed, which have been manufactured using or containing 
CFCs. Furthermore, the insulation materials should not contain components, which outgas at the stagnation temperature, specified in Clause 6, which are toxic and seriously irritant to the human skin or eyes. 
B.3  Recycling of the collector materials 
Solar collectors are mainly used to save energy and re duce pollution. Therefore the design of the collectors 
should take into consideration the possibility to recyc le the materials used. Materials which are not to be 
recycled should be avoided or used to the lowest possible extent. 
 
 
 
 FDUS 854-1: 2009 
© UNBS 2009 – All rights reserved  9
 Annex C  
(informative) 
 
Tests to be repeated in co llector design modifications 
If the collector design is changed, Table C.1 may be used as guideline to assess whether one or more test 
should be repeated. 
Table C.1 – Test that should be repeated for the respective modification in the collector design 
 Absorbers Covers  Insulation 
materials Boxes  Reflectors  Diffusion 
barriers 
Thermal performamce + + + + + + 
Internal pressure + - - - _ - 
High temp, resistance + + + + + + 
Exposure  + + + + + + 
External thermal shock - + _ + + _ 
Internal thermal shock + - -  - - _ 
Train penetration - + -   + - _ 
Mechanical tests - + -   + _ - 
Final inspection + + + + + + 
+ Test should be repeated 
- Test need not be repeated 
 
 FDUS 854-1: 2009 
10 © UNBS 2009 – All rights reserved
 Bibliography 
[1] ISO 9806-1, Test methods for solar collectors - Part 1: Thermal performance of glazed liquid heating 
collectors including pressure drop . 
[2]  ISO 9806-2, Test methods for solar collectors - Part 2: Qualification test procedures 
[3]   ISO 9806-3, Test methods for solar collectors - Part 3: Thermal performance of unglazed liquid heating     
collectors (sensible heat transfer only) including pressure drop 
[4]  ISO 9808, Solar water heaters - Elastomeric materials for absorber s, connecting pipes and fittings -  
Method of assessment 
[5]  ISO/TR 10217, Solar energy - Water heating systems - Guide to material selection with regard to internal 
corrosion 
 FDUS 854-1: 2009 
© UNBS 2009– All rights reserved 
 Certification marking 
Products that conform to Uganda standards may be  marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is gove rned by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licens ed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in co njunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and  testing in accordance with the 
certification mark scheme of the Uganda National  Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of  licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 FDUS 854-1: 2009 
 
ICS 27.160. 
Price based on es 
© UNBS rved 
  nn pag
2009 – All rights rese