FINAL DRAFT UGANDA 
STANDARD  FDUS 857-1
First Edition
2009-mm-dd
 
Reference numbe  
r
FDUS 857-1: 2009
 © UNBS 2009 
  
Custom built solar systems - Part 1: General requirements  
 FDUS 857-1: 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 41 4505995  
Fax: 256 41 4286 123 
E-mail: unbs@infocom.co.ug
Web: www.unbs.go.ug   FDUS 857-1: 2009 
© UNBS 2009 – All rights reserved  iii
 Contents Page 
Foreword………………………………………………………………………………………………..…………iv 
1   Scope ....................................................................................................................................................1  
2  Normative references ...........................................................................................................................1  
3  Terms and definitions ..........................................................................................................................2  
4    Symbols and abbreviations ................................................................................................................3  
5    System classification ..........................................................................................................................3  
5.1   Small custom built systems ................................................................................................................3  
5.2  Large custom built systems ................................................................................................................3  
6    Preconditioning ...................................................................................................................................4  
6.1   General .................................................................................................................................................4  
6.2   Materials ...............................................................................................................................................5  
6.3   Component s and pipework ...............................................................................................................5  
6.4   Safety  equipment and indicators ......................................................................................................8  
6.5  Installation .............................................................................................................................................9  
6.6  Initial operation and commissioning ..................................................................................................9  
6.7  Documentation ............................................................................................................................... ....10  
6.8   System performance ..........................................................................................................................11  
 FDUS 857-1: 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 Energy Management 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 FDUS 857-1: 2009 
© UNBS 2009 – All rights reserved  v
  
 FINAL DRAFT UGANDA STANDARD FDUS 857-1: 2009
 
© UNBS 2009– All rights reserved 1
 Custom built solar systems – Part 1: General requirements 
1   Scope 
This standard specifies requirements on durability, reli ability and safety of small and large custom built solar 
heating systems with liquid heat transfer medium for residential buildings and similar applications. The 
standard contains also requirements on the des ign process of large cu stom built systems. 
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 amendments) applies. 
ISO 9488, Solar energy - Vocabulary 
US 854-1: 2009, Uganda Standard — Thermal solar systems and components — Solar collectors — General 
requirements   
ISO 21003-1, Multilayer piping systems for hot and cold water installations inside buildings — Part 1: General 
ISO 21003-3, Multilayer piping systems for hot and cold water installations inside buildings — Part 3: Fittings 
ISO 21003-5, Multilayer piping systems for hot and cold water in stallations inside buildings — Part 5: Fitness 
for purpose of the system 
EN 806-1, Specifications for installations inside buildings  conveying water for human consumption — Part 1: 
General 
ISO 9774, Thermal insulation for building applications — Guidelines for selecting properties 
ISO 6612, Windows and door height windows — Wind resistance tests 
ISO 15783, Seal-less rotodynamic pumps — Class II — Specification 
ISO 9906, Rotodynamic pumps — Hydraulic performance acceptance tests — Grades 1 and 2 
EN 1717, Protection against pollution of potable water in drinking water installations and general requirements 
of devices to prevent pollution by backflow 
ISO 1129, Steel tubes for boilers, superheaters and heat  exchangers — Dimensions, tolerances and 
conventional masses per unit length 
ISO 16528, Boilers and pressure vessels 
IEC 60335-1, Safety of household and similar electrical appliances — Part 1: General requirements 
IEC 60335-2-21, Safety of household and similar electrical app liances — Part 2: Particular requirements for 
storage water heaters FDUS : 2009 
2 © UNBS 2009 – All rights reserved
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IEC 61024-1, Protection of structures against lightning — Part 1: General principles 
ISO 9459-1, Solar heating — Domestic water heating systems — Part 1: Performance rating procedure using 
indoor test methods 
ISO/TR 10217, Solar energy — Water heating systems — Guide to material selection with regard to internal 
corrosion  
US 854 -1, Thermal solar systems and components — Solar collectors — Part 1: General Requirements 
US 854 -2, Thermal solar systems and components — Solar collectors — Part 2: Test methods 
US 855 -1, Thermal solar systems and components — Factory made systems — Part 1: General 
requirements 
DUS 857-2,  Custom built systems — Part 2: Test methods 
DUS 857-3,  Custom built systems — Part 3:  Performance characterization of stores for solar heating systems 
3  Terms and definitions  
For the purposes of this standards, the terms and def initions given in US 854-1, US 855-1 and ISO 9488 apply 
together with the following. 
3.1  assortment 
complete list of components (collectors, shoes, contro llers, pumps etc) which a company offers for its solar 
heating systems. For the purpose of this standard the assortment is rest ricted to components used for small 
custom built heating system s marketed by a company.   
3.2  assortment file 
technical documentation file for small custom built systems of a company which includes: 
-  the complete assortment for small custom built systems 
-  the complete description of all marketed combin ations of system configurations and components 
including the component dimensions and number of units 
-  further technical information 
3.3  collector array 
group of collectors that are closely connected in series , in parallel or in combination of both modes, with one 
hydraulic input and one hydraulic output 
3.4 expansion line 
for systems with closed expansion vessels, the co nnecting line between the collectors and the pressure 
expansion vessel 
for systems with open expansion vessels, the connecti ng line between the collector array and the open 
expansion vessel 
3.5 large custom built system 
solar heating system for the purpose of hot water prepar ation and/or space hating. It is designed for a specific 
situation by combining various components to a unique system. 
NOTE 1 In general, large custom built systems are design ed by HVAC engineers, manufacturer or other experts. 
NOTE 2 In general, the collector area is greater than 30m2 and the store volume is greater than 3m3FDUS : 2009 
© UNBS 2009 – All rights reserved  3
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3.6 safety line 
systems with closed expansion vessels: connecting line between the collector array and the safety valve 
systems with open expansion vessels: connecting line between the collector array and the open expansion 
vessel 
3.7 small custom built system 
modular solar heating system of the remote storage type for the purpose of hot  water preparation and/or 
space heating. The system has a well  identified configuration (see definit ion in 3.8). It is assembled from 
components chosen from the market and described in an assortment file prepared by a company 
NOTE 1 In general the assortment file includes the possible system configurations, the a ssortment of components and 
their possible combinations and dimensions. The ‘company’ may be the manufacturer of all or of parts of the components 
in the assortment; this company may also be only a consulting engineer who just produces the technical documentation 
and purchases the components from suppliers. 
NOTE 2 In general, the collector area is greater than 1 m2 and less than 30 m2 and the store volume is less than 3m3. 
NOTE 3 The system can be tested by experimentally testi ng the components and predicting  the system performance for 
different combinations of components by computer simulation . 
3.8 system configuration 
characteristics of a solar heating sy stem including its hydraulic scheme (hydraulic connections between the 
collector array, the store(s) and other components) and its control concept. Systems differing by any other 
parameter, by the type or dimensions of the used comp onents or the controller settings are considered to 
have the same configuration 
4    Symbols and abbreviations  
(UA) S,a,sb  stand-by heat loss rate of the store 
VS   store volume 
5    System classification  
5.1   Small custom built systems 
Small custom built systems are classified as described in clause 5 of ISO 9459 -1. According to the purpose of 
these systems the following additional classification applies (see Table 2): 
Table 2 – Classes of small custom built systems according to their purpose 
Class Purpose  
A Hot water preparation only (domestic) 
B Space heating only 
C Hot water preparation and space heating 
 
5.2  Large custom built systems  
Large custom built systems are classified in accordance with Table 3. 
 FDUS : 2009 
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Table 3 – Classification of large systems 
Class Purpose 
A A system in which the store(s) and the collector array(s) are located in one 
building for which the heat is provided. No seasonal store and no heat distribution 
network outside the building are included. 
B A system which consists of a central heating plant and one or more collector 
array(s). the heat is transported via a heat  distribution network to the heating plant 
and/or to other buildings. No seasonal store is included. 
C A large custom built system which mainly  consists of one or more large collector 
array(s) and in which the heat is transfer red to seasonal store or directly into a 
heat distribution network. 
NOTE      Large systems of type A are generally used for large multi-family houses. 
Large systems of type B are generally used for distri ct heating systems without any seasonal store. 
Large systems of type C are generally us ed for large district heating systems. 
6    Preconditioning  
Subsequent requirements refer to the test methods given in DUS 857-2. 
NOTE The numbering of the following clauses is kept in direct correspondence to the numbering of DUS 857-2 . 
6.1   General 
6.1.1 Suitability for drinking water 
See EN 806-1. 
6.1.2 Water contamination 
See EN 1717. 
NOTE See also the introduction about water quality . 
6.1.3 Freeze resistance 
See 4.1.3 of DUS 855-1 
6.1.4 Overheating protection 
6.1.4.1 Scald protection 
Systems, in which the temper ature of the hot water delivered to the user can exceed 60 oC, shall be fitted with 
an automatic cold water mixing device or any other de vice to limit the temperature to at maximum 60 oC shall 
be installed. 
6.1.4.2 Overheating protection for materials 
The design of the system shall ensure that the hi ghest permissible temperatures to which the system 
components may be exposed are not exceeded. 
NOTE Care should be taken in cases where under stagnation conditions steam or hot water can enter the collector 
pipes, pipework, distribution network or heat exchanger. 
6.1.5 Reverse flow prevention FDUS : 2009 
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The installation of the system as described in the hydraul ic scheme shall ensure that no unintentional reverse 
flow occurs in any hydraulic loop of the system. 
6.1.6 Pressure resistance 
The store tank and the heat exchangers in this tank shall comply with the requirements given in ISO 16528. 
the collector shall comply with the requirements given in US 854 -1. 
Any components in the systems which are not covered by ISO 16528 or US 854-1 shall withstand the lower of the following pressures: 
- 1.5 times the manufacturer’s st ated maximum working pressure, 
- The manufacturer’s stated maximum test pressure 
For the part of the system in which these component is used. 
NOTE 1 In addition collector arrays of large custom built  systems should be designed in a way, that they can also 
withstand short and high pressure peaks. 
NOTE 2 If, due to stagnation, considerable heat transfer medium quantities in the collector array evaporate, pressure 
peaks may occur due to high flow velocities of steam or liquid.  These pressure peaks may significantly exceed the release 
pressure of the safety valve. 
6.1.7 Electrical safety 
See IEC 60335-1 and IEC 60335-2-21 
6.2   Materials 
Any parts of the system to be mounted outdoors sha ll be resistant to UV radiation and other weather 
conditions over the prescribed maintenance interval. Wh en any maintenance or replacement of system parts 
is required in order to maintain the system's working or der over a period of 10 years, this shall be clearly 
stated in the documents for the user. 
All materials used in the collector loop should comply  with ISO/TR 10217 in order to avoid any internal 
corrosion. 
6.3   Component s and pipework 
6.3.1 Collector and collector array 
The collector shall meet the requirements given in US 854-1. 
For parts and joints of the collector array see 6.3.8. 
NOTE 1  Care should be taken in order to ensure l ong term durability and tightness of the collector joints.  
If the collector array includes several parallel connected rows of collectors, the maximum disparity of the mass 
flow rate per unit collector area of each row should not exceed 20 % of the nominal flow rate per unit collector 
area of the whole array. 
NOTE 2  In general, balanced flow can be reached by means of hydraulic adjustment of collectors and tubes. If  this is not 
possible, the flow can be controlled by suitable fittings. 
6.3.2 Supporting frame 
If part of the system is installed on an outdoor frame, t he resistance of the frame to wind loads in accordance 
with ISO 6612 shall be proved by calculation with refe rence to the local conditions. The manufacturer shall FDUS : 2009 
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specify the maximum values for vm (mean wind velocity) according to ISO 6612. The system may only be 
installed at locations, where the values of vm determined according to ISO 6612 are lower than the maximum 
values stated by the manufacturer. This shall be ment ioned in the documents for the installer (see also 6.7.2). 
6.3.3 Collector and other loops 
If the collector loop is provided with a circulation pump, the pressure drop in the whole loop should remain 
acceptable. The parasitic electrical power of the pump should not exceed the values given in Table 4. 
Table 4 – Maximum electrical power of the pump 
System Electrical power of the pump 
Small systems 50 W or 2% of the highest heat power which can be delivered by the 
collector array, whichever higher 
Large systems 1 % of the highest heat power wh ich can be delivered by the collector array 
 
The maximum pump power stated above excludes the powe r of pumps in drain-back systems that is only 
needed to refill the system after drain-back. 
Other possible heat transfer loops within the system should be designed by comparing the parasitic power of their pump(s) to the highes t heat power transmitted. 
6.3.4 Circulation pumps 
See ISO 9906 and ISO 15783. 
6.3.5 Expansion vessels 
For drain-back systems, a separate expansion vessel is not necessary, when the drain-back facility is 
adequately designed to fulfill its task, in terms of volume, temperature and pressure resistance. 
6.3.5.1 Open expansion vessels 
Each open system shall be provided with an expansion vessel, the volume of which shall be dimensioned such that it is capable of absorbi ng at least the entire expansion of the heat transfer medium between the 
lowest and the highest possible operating temperatur e. Each expansion vessel shall be provided with a 
connection to atmosphere, which cannot be shut off, and with a spill line. 
6.3.5.2 Closed expansion vessels 
For small systems: 
The expansion device of the collector loop shall be dime nsioned such, that even after an interruption of the 
power supply to the circulation pump in the collector loop just when solar irradiance is maximum, operation 
can be resumed automatically after power is available again. 
When the heat transfer medium can evaporate under stagnation conditions this rule implies a special 
dimensioning of the expansion volume: In addition to the dimensioning as it is usual for closed space heating 
systems (expansion of the whole heat transfer medium), th e expansion vessel shall be able to compensate for 
the volume of the heat transfer medium in the whole co llector array including all connection pipes between the 
collectors plus 10 %. 
Alternatively, when the system does  not automatically resume operation after stagnation conditions, a warning 
shall be added to the operating instructions. 
The manufacturer's instructions shall be followed. FDUS : 2009 
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No requirements for large systems. 
6.3.6 Heat exchangers 
If the system is intended to be used in areas with high water hardness and at temperatures above 60 °C, heat 
exchangers in contact with drinking water shall be desi gned such that scaling is prevented or there shall be a 
means for cleaning. 
NOTE 1  High temperature difference between the metal surf ace of the heat exchanger an d the surrounding drinking 
water mainly causes scaling. This can be avoi ded by increasing the heat exchanger area. 
Any heat exchanger(s) between the collector loop and the hot water supply system should not reduce the 
collector efficiency due to an increase of the collect or's operating temperature by more than the following 
criterion specifies: 
When the solar gain of the collector has reached its hi ghest possible value, the reduction of the collector 
efficiency induced by the heat exchanger should not exceed 10 % (absolute). If more than one heat 
exchanger is installed, this value should also not be  exceeded by the sum of reductions induced by each of 
them. The criterion also applies if a load-s ide heat exchanger is part of the system. 
NOTE 2  If only one heat exchanger is used between the colle ctor loop and the store of a sm all custom built system, the 
heat transfer rate of the heat exchanger per unit collector area should not be less than 40 W/(K m2). 
6.3.7 Store 
Stores for drinking water and parts of combined stores which are in contact with drinking water shall comply 
with the requirements in ISO 16528. 
Stores of small custom built systems shoul d be tested as described in DUS 857-3. 
The stand-by heat loss rate ( UA)S,a,sb of stores of small custom built systems should not exceed the value 
given by equation (1): 
(UA)S,a,sb = 0.16 VS  i n  W / K                ( 1 )  
where VS is the nominal volume of the store in litres. 
NOTE  Equation (1) is derived from figures specified in the Swiss regulation and the Italian code for hot water stores. 
No requirement on the heat loss rate of stores of large custom built systems 
6.3.8 Pipework 
The pipe length of the system shall be as short as possible. The pipes and fittings shall be selected from 
materials that are compatible with the components included in each loop, according to the fluid of the loop as 
specified in the ISO/TR 10217. 
The design of the system and the used materials shall be such that there is no possibility of clogging and lime 
deposit in its circuits which would drasti cally influence the system performance. 
The pipework for drinking water shall comply with the requirements specified in EN 806-1. The materials for 
pipes and fittings shall be suitable to withstand the ma ximum operating temperature (stagnation conditions) 
and pressure. The pipework shall withstand therma l expansion without any damage or detrimental 
deformation. 
Venting of the system shall be possible. No automatic vents shall be placed in parts of the collector loop 
where vapour can occur (e.g. the top of the collector array), except a manual valve is foreseen between the 
pipe and the automatic vent, this valve being closed du ring normal operation of the system, or except a FDUS : 2009 
8 © UNBS 2009 – All rights reserved
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warning is added to the operating instructions, indicati ng that the system does not automatically resume 
operation after stagnation conditions. 
6.3.9 Thermal insulation 
The thermal insulation of all connecting pipes and other  components of the system should comply with the 
requirements given in ISO 9774. 
The collector loop should be insulated without any gap s between the components. Thermal bridges, e.g. 
incorrectly installed mounting clamps should be avoided.  
The thermal insulation of the pipework shall be fr om materials which are resistant to the maximum 
temperature of the circuit and deformation and which remain operative. If the insulation is installed outside, it 
shall be protected from solar radiation, weather conditions and animal impact. 
Insulated pipes for underground installation shall comply with ISO 21003. 
6.3.10 Control system 
6.3.10.1 Controller 
The controller of a small custom built system should be tested as described in 7.3 of DUS 857-2. 
No requirement for large custom built systems. 
6.3.10.2 Temperature sensors  
The collector temperature sensor s hall withstand stagnation conditions as  specified in US 854 -2 without 
altering by more than 1 K. 
The store temperature sensor shall withstan d 100 °C without altering by more than 1 K. 
The location and installation of all temperature sensors shall ensure a good thermal contact with the part of 
which the temperature shall be measured. The temperature sensors shall be insulated against ambient. 
6.4   Safety  equipment and indicators 
6.4.1 Safety valves 
Each section of the collector array which can be shut o ff shall be fitted with at least one suitable safety valve 
of suitable dimension. The safety valve shall resist  the temperature conditions which it is exposed to, 
especially the highest temperature t hat can occur. The safety valve sha ll resist the heat transfer medium. The 
safety valve shall be dimensioned such that it can release the highest flow of hot  water or steam that can 
occur. The dimension of the safety valv e(s) shall be proved by suitable means. 
6.4.2 Safety lines and expansion lines 
The safety line shall not be capable of being shut off. 
The safety line and expansion line shall be dimensioned such, that for the highest flow of hot water or steam that can occur, at no place in the collector loop the maximum allowed pressure is exceeded due to the 
pressure drop in these lines. The dimensions of the safety line and expansion line shall be proved by suitable 
means. 
The expansion line and the safety line shall be connected and laid in such a way that any accumulation of dirt, 
scale or similar impurities are avoided. 
6.4.3 Blow-off lines FDUS : 2009 
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The blow-off lines shall be laid in such a way that th ey cannot freeze up and that no water can accumulate 
within these lines. The orifices of the blow-off lines s hall be arranged in such a way that any steam or heat 
transfer medium issuing from the safety valves does not  cause any risk for people, materials or environment. 
6.4.4 Store shut-off valve 
Stores of large custom built system s with a volume of more than 20 m3 shall be fitted with shut-off valves or 
other suitable devices to stop unintentional outflow of  the store content in cases of system hazards. 
6.4.5  Indicators 
6.4.5.1 Indicators for collector loop flow 
The system should be fitted with any indicator for the collector loop flow. This can be either a flow rate 
indicator or two thermometers which indicate the actual  flow and return temperatures of the collector loop. 
6.4.5.2 Pressure gauge 
For the indication of the actual overpressure, collector loops which are filled under overpressure shall be fitted 
with a pressure gauge at a clearly visible spot of the installed system. The range of the working overpressure 
shall be marked. 
6.4.5.3 Heat meter 
No requirements for small custom built systems. 
The collector loop of large custom built systems should be equipped with a heat meter. 
6.5  Installation 
If collectors are installed on the roofs of buildings, the tightness of the roof cover shall not be impaired. 
The components which are exposed to the effects of w eather shall be weathering resistant. They shall be 
designed, constructed and fastened in such a way t hat they are resistant to the following hazards: 
6.5.1 Lightning 
The system shall meet the requi rements given in IEC 61024-1. 
NOTE In annex F of US 855-2 a revised version in respect of solar heating systems of t he requirements in IEC 61024-1 
is given. 
6.5.2 Wind loads 
If parts of the system are installed outdoors, they shall be resistant to wind loads according to ISO 6612. The 
manufacturer shall state the maximum values for vm (mean wind velocity) according to ISO 6612. The system 
may only be installed at locations, where the values of vm determined according to ISO 6612 are lower than 
the maximum values stated by the manufacturer. This shall be mentioned in the documents for the installer 
(see also 6.7.2). 
6.6  Initial operation and commissioning 
No requirements for small custom built systems. 
Before initial operation of a large custom built system it shall be ensured that: 
-  the installed system complies with the requirements of this standard. FDUS : 2009 
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-  corresponding fittings are adjusted and the adjustments are recorded. 
-  the supervisor of the system, if there is one, is instructed. 
Large systems should be tested as specified in Annex C of DUS 857-2 and monitored as specified in Annex D 
of DUS 857-2. 
NOTE  The procedures described in Annexes C and D of DUS 857-2 are optional. 
6.7  Documentation 
The documentation of the system as described below shall be complete and understandable. 
For small systems a technical documentation descri bing the assortment proposed by the company having 
established the file according to 6.7.1 should be available. Documentation according to 6.7.2 shall be provided 
with each system. 
For large systems the full documentation of the system according to 6.7.3 shall be provided. 
6.7.1  Assortment file for small systems 
The documentation describing an assortment of small systems should include the following information: 
a) All proposed system conf igurations including related hydraulic and control schemes and specifications to 
enable the user to understand the operating mode of the system. 
b) A list of all components to be included into the abov e system configurations, with full reference to 
dimension and type. The identification of t he listed components shall be easy and unambiguous. 
c)  A reference to all required component test reports according to 6.8. 
d)  A list of proposed combinations of dimens ion options within each system configuration. 
e)  Diagrams or tables stating the system perform ance under reference conditions for each proposed 
combination of dimension options within each system  configuration. The reference conditions should be 
completely specified including the assumptions ma de on heat load(s) and weather data; the heat load(s) 
assumed should cover the range between 0.5 and 1.5 times the design load specified by the manufacturer. 
6.7.2  Documentation for small systems 
All components of each small custom built system s hall be provided with a set of understandable assembly 
and operating instructions as well as service reco mmendations. This documentation shall include all 
instructions necessary for assembly, installation, opera tion and maintenance. These instructions shall include 
all information as listed in 4.6 of US 855-1. 
The documents shall be kept at a visible place (prefer ably nearby the store), protected from heat, water and 
dust. 
6.7.3  Documentation for large systems 
Each large custom built system shall be provided with a set of assembly and operating instructions as well as 
service recommendations. This documentation shall in clude all instructions necessary for assembly, 
installation, operation and maintenance and all record s of initial operation and commissioning according to 
6.6. 
The documents shall be kept at a visible place (prefer ably nearby the store), protected from heat, water and 
dust. FDUS : 2009 
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6.7.3.1  Documents in respect of dimensioning 
The documentation should include:  
a)  All load assumptions made (offering a set of values in a range spanning ± 30 % around the selected 
average load); 
b)  A full reference to the weather data used; 
c)  A full record of the dimensioning method used fo r collector area, store dev ice(s) and heat exchanger 
including all assumptions (e. g. the desired solar fraction) and the full reference to any simulation 
programme used; 
d)  A full record of the procedures used for hydraulic  dimensioning of the collector loop and its components; 
e)  A full record of the procedures used for the predi ction of the system therma l performance including the 
full reference to any simulation programme used. 
6.7.3.2  Documents for assembly and installation 
The documents shall comply with a), e) to h), j) and k) of 4.6.1 in US 855-1. 
The description of assembly and inst allation of the system shall enable a pr oper installation in accordance 
with the system drawings. 
6.7.3.3  Documents for operation 
The documentation shall comply with in paragraphs a), f) and g) of 4.6.2 of US 855-1. 
The documents shall also include: 
a)  Hydraulic and electric al schemes of the system; 
b)  Description of the safety system with referenc e to location and adjustment of the safety components; 
NOTE  Guidance should be given for a check of the system before taking it into operation again after one or more 
safety valves released . 
c)  Intended action in the case of system failure or  hazard which is specified in the safety concept; 
d)  Description of the control conc ept and the control system including t he location of the control components 
(e.g. sensors). The control components should be included in the hydraulic scheme of the system; 
e)  Maintenance instruction including start-up and shut-down of the system; 
f)  Check on function and performance. 
6.8   System performance 
Small systems should be performance tested as described in DUS 857-2. The test resu lts should be listed in a 
test report in accordance with Clause 8 of DUS 857-2. 
No requirements for large custom built systems. FDUS : 2009 
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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 857-1: 2009 
 
ICS 27.160 
Price based on nn pages 
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