FINAL DRAFT UGANDA 
STANDARD  
  FDUS ISO TR 
10217
First Edition
2009-mm-dd
 
Reference numbe r
FDUS ISO TR 10217:1989
 © UNBS 2009
  
Solar energy — Water heating systems — Guide to material 
selection with regard to internal corrosion 
 FDUS ISO TR 10217: 1989 
 
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responsible for its correct application  
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 FDUS ISO TR 10217:1989  
© UNBS  2009 - All rights rese rved                iii National foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of U ganda. UNBS is mandated to co-ordinate the elaboration 
of standards and is  
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The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
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for approval and declaration as Uganda Standards by the National Standards Council. 
This Final Draft Uganda Standard, FDUS ISO TR 10217, Solar energy — Water heating systems — Guide to 
material selection with regard to internal corrosion,  is identical with and has been reproduced from an 
International Standard, ISO TR 10217:1989, Solar energy — Water heating systems — Guide to material selection with regard to internal corrosion, and is being proposed for adoption as a Uganda Standard.  
This standard was developed by the Energy Management Standards Technical Committee (UNBS/TC 13). 
Wherever the words, "International Standard" a ppear, they should be replaced by "Uganda Standard." 
 TECHNICAL 
REPORT ISO 
TR 10217 
First edition 
1989-09-15 
Solar energy - Water heating Systems - Guide 
to material selection with regard to internal 
corrosion 
Energie solaire - S ystkme de production d’eau chaude - Guide pour Ie choix de 
matkiaux vis-a-vis de Ia corrosion interne 
Reference number 
ISO/TR 10217 : 1989 (EI ISO/TR 10217:1989 (EI 
Foreword 
ISO (the International Organization for Standardization) is a worldwide federation of 
national Standards bodies (ISO member bodies). The work of preparing International 
Standards is normally carried out through ISO technical committees. Esch member 
body interested in a subject for which a technical committee has been established has 
the right to be represented on that committee. International organizations, govern- 
mental and non-governmental, in liaison with ISO, also take part in the work. ISO 
collaborates closely with the International Electrotechnical Commission (IEC) on all 
matters of electrotechnical standardization. 
The main task of ISO technical committees is to prepare International Standards. In 
exceptional circumstances a technical committee may propose the publication of a 
technical report of one of the following types : 
- tYPe 1, when the necessary support within the technical committee ca nnot be 
obtained for the publication of an International Standard, despite repeated efforts; 
- tYPe 2, 
exposure; when the su bject is still under technical development requiring wider 
- type 3, when a technical committee has collected data of a different kind from 
that which is normally published as an International Standard (“state of the art”, for 
example). 
Technical reports are accepted for publication directly by ISO Council. Technical 
reports of types 1 and 2 are subject to review within three years of publication, to 
decide whether they tan be transformed into International Standards. Technical 
reports of type 3 do not necessarily have to be reviewed until the data they provide are 
considered to be no longer valid or useful. 
ISO/TR 10217, which is a technical report of type 3, was prepared by Technical 
Committee ISO/TC 180, Solar energy. 
Annex A of this Technical Report is for information only. 
0 ISO 1989 
All rights reserved. No patt of this publication may be reproduced or utilized in any form or by any 
means, electronie or mechanical, including photocopying and microfilm, without Permission in 
writing from the publisher. 
International Organization for Standardization 
Case postale 56 l CH-1211 Geneve 20 l Switzerland 
Printed in Switzerland TECHNICAL REPORT ISO/TR 10217 : 1989 (E) 
Solar energy - Water heating Systems - Guide to 
material selection with regard to internal corrosion 
1 Scope 
This Technical Report provides a discussion of the Parameters 
that have a bearing on the internal corrosion of solar water 
heating Systems. 
The following topics are not dealt with in this Technical 
Report : 
- Problems of compatibility between polymeric materials 
(plastics and rubber) and fluids; 
- corrosion risks concerning the enclosure and the 
external surface of the absorber; 
- safety and health questions, especially the toxicity of 
heat-transfer fluids. 
In many fields, the corrosion Problem is hard to deal with, 
because it overlaps several matters. As far as solar Systems are 
concerned, corrosion prevention cannot be treated only in 
respect of a component, or only as a durability Problem, or only 
as a design Problem. lt cannot be solved only by specific tests, 
or only by design recommendations. 
This Technical Report addresses the question of which re- 
quirements are necessary, to predict with confidence long 
failure-free lifetimes in active solar Systems, from the Point of 
view of internal corrosion. lt gathers information provided in 
previous Papers on this subject Iespecially bibliography 
references 2, 3 and 4) while staying in agreement with them. 
2 Corrosion risk Statement 
If corrosion effects are considered as a reliability Problem for 
the System, because corrosion tan reduce the quality of the 
System, the following Points may be detailed. 
2.1 The degradating agent is internal corrosion. Its effects 
are different according to 
- materials; 
- couples of materials; 
- temperature; 
- fluid circulation; 
- fluid Oxygen content; 
- fluid aggressive ions content. 2.2 The materials concerned are 
- absorber materials; 
- pipes and fitting materials; 
- fluids; 
- welding materials. 
2.3 The functional characteristics of the System are 
- pressure resistance; 
- efficiency of thermal transfer between the sun and the 
storage; 
- high and low temperature resistance. 
2.4 The failure modes (i.e. the ways for the degradating 
agent to act on the materials to weaken their functional 
characteristics or those of the System) are 
- bad design choice (materials and conditions of use of 
the System); 
- degradation of materials during Service life; 
- bad maintenance. 
3 Discussion 
Internal corrosion darnage in solar Systems is generally detected 
too late: it is reported as a serious Problem, which requires 
replacement of significant Parts of the System [SI, but inspection 
studies [Q 131 give little information on this subject; a visual 
inspection, even completed by user-consultation, is not able to 
show the growing effects of internal corrosion before the first 
pitting occurs. 
Among the types of darnage reported, most are related to the 
use of aluminium absorbers without precautionsW 
Several documents treat the corrosion Problem as presented 
previously : it is a whole-System Problem, and initial design and 
material-choice recommendations are emphasized as a way to 
prevent corrosion damage[z! 111. Even in Standards, the pro- 
blem is sometimes left to expert advice[W A table of accep- 
table or unacceptable conditions tan summarize all the data 
given about installation Parameters, metaI/fluid pairs and metal 
association 11 I 41. 
1 ISO/TR 10217 : 1989 (E) 
Nevertheless, there exists the need to envisage specific tests to 42.1 Test for the fluid/metaI pair 
predict with greater confidence the Service life of the System. 
Classic laboratory corrosion tests may be used to study the 
metal and fluid compatibility[I41, and specific ones are used 
experimentally to simulate solar System characteristics [5,*1. In 
the USA, such specific laboratory tests are standardizedL61. 
Another type of test is also performed in several laboratories, 
which simulates Service conditions, generally based on test 
loops Dr*1 and even real systems[gl. To appreciate the behaviour of the fluid at high temperature, 
laboratory tests have been mentioned [5,*] : a metal/fluid pair 
tan be submitted to high temperature, up to 100 OC, in a glass 
Container at atmospheric pressure, or in an autoclave to resch 
higher temperatures. After this ageing, corrosion of the metal is 
measured by mass losses and visual inspection, and the 
fluid is analysed. Ageing processes are described in ASTM 
Standard E 745[71, and the qualification tests are traditional. 
However, most of the papers[2Jt43f 10,llJ 151 emphasize the 
usefulness of a good maintenance Programme to prevent fluid 
degradation (closed loops), and/or water (organic fluids) entry, 
effects of erosion, etc. lt is possible to perform electrochemical measurements on 
some kinds of metals, especially those which are sensitive to 
pitting corrosion, using the degradated fluid as liquid medium. 
This type of test is not specific to solar applications, and it is 
possible to use traditional procedures. Where the pipe material 
is brass, dezincification resistance may be determined using the 
4 Proposal for a procedure to prevent internal 
corrosion darnage test method given in ISO 6509[% 
4.2.2 Test for the loop 
4.1 General 
After viewing the literature, it appears clear that a procedure to 
prevent internal corrosion darnage has to include two Steps, 
namely : Another test method uses an experimental loop where metal 
samples are tubes making part of the loop, and where the fluid 
is circulating in the loop. Temperature and liquid velocity are 
Parameters of the test, and corrosion is measured by mass 
losses or possibly by an electrochemical test[*L The loop is 
a) recommendations concerning the design of the instal- described in ASTM Standard E 745[7l. 
lation; 
4.3 Recommendations concerning maintenance 
b) recommendations concerning the maintenance. 
Recommendations for maintenance have to take into account 
The first step must give indications on the acceptable con- 
ditions concerning working modes of the installation, metal and 
fluid combinations, etc. Sometimes, tests may be necessary to 
draw firm conclusions, and some recommended test methods 
have already been standardized. the field information collected, in addition to scientific 
knowledge on metal and fluid compatibility, and on heat- 
transfer fluid degradation. The following procedure sum- 
marizes the indications of several documents Pr% J15, 11,151. 
4.3.1 Starting Operation 
The second step gathers maintenance advice in Order to ensure 
continuation of the good conditions selected following the 
indications of the first Step. The System and its components must be protected against con- 
tamination and overheating during storage and assembly, and 
before being filled. 
4.2 Recommendations concerning design 
When the installation design has been determined, including 
loop type (closed or open), absorber material, pipe material, 
fluid type and composition, fluid velocity, etc., tables 1 and 2 
are used to check whether the System Parameters give accept- 
able or unacceptable conditions for the prevention of internal If the heat-transfer fluid is aqueous, flush the unit out with 
water; if the heat-transfer fluid is organic, flush the unit out 
using the correct organic fluid. Immediately after this flushing 
Operation, a pressure test is carried out. The flushing out and 
pressure test are immediately followed by filling with heat- 
transfer fluid. 
corrosion darnage. 
These two tables gather information previously produced in 
bibliography references 1 and 4. lt is recommended that ready-diluted antifreeze fluids be used, 
under the manufacturer’s recommendations. 
4.3.2 Operation and shutdown of the solar System 
The tables given are probably sufficient to check the good 
design of the System, but they do not provide information on 
the reliability of the materials over their Service life (absorber 
materials, pipe materials and fluids). 
lt is therefore proposed to use some existing tests to appreciate 
the effect of time on the materials in use. These tests, which 
have been developed in various laboratories Fr*, 91, may also be 
used in the cases of design choices for which tables recom- 
mend a detailed study. The circulatory System must always remain filled ready for 
Operation, even during the Winter months. Components in the 
heat-transfer fluid tan concentrate in Systems which are partly 
or completely empty as a result of vaporization of the remaining 
heat-transfer fluid. In this case, protection against corrosion 
provided by inhibitors tan fail, so that pitting is possible. 
Should a shutdown or emptying of the System become 
necessary, for instance because of repair work, it is advisable to 
cover the collector surfaces to avoid over-heating. Repairs have 
2 ISO/TR 10217 : 1989 (EI 
to be carried out in such a way that boiling of the heat-transfer 
fluid is effectively prevented, and the System should be refilled 
as soon as possible. 
Should losses in the amount of fluid occur because of leakage, 
then these have to be compensated for by addition of the same 
heat-transfer fluid as that used initially. 
Losses caused by evaporation of water tan be compensated for 
by addition of ordinary water, as long as the supplier of the fluid 
does not stipulate any other requirements. 
4.3.3 Annual inspection 
An annual inspection of the installation has to be made by a 
qualified person. During these inspections, the following oper- 
ations should be performed : a) check the fluid level; 
b) check the air vents; 
c) take a Sample of the heat-transfer fluid in Order to check 
- the pH value; 
- the freezing Point; 
- the alkaline reserve; 
- the metallic traces in Suspension. 
For aluminium absorbers, it is recommended that the fluid be 
replaced after 2 years. 
Table 1 - MateriaVfluid combinations for closed Systems 
Absorber 
material 
Aluminium Aqueous fluid (with or without addition of glycol) 
Organic Pipes and fittings materials 
Untreated With Velocity 
PH Temp. fluid Galv. 
inhibitors m/s OC Copper Steel steel Polymer 
no Cu+ + 
no Fe+ + < 1,22 > 5 
< 9 no H,O l ” l 2),7) 
no Cl- 
Galvanized > 8 6) 
steel < 12 < 55 no H,O l 2),7) 
Steel < 1,83 > 8 
< 12 no H,O l 2),7) 
Stainless 0 3’ l 3’ 
steel Cl- <50ppm Cl- <50ppm l 2),7) 
Copper no NH,+ < 1,22 l 2),7) 
Polymer l 4’ l 5) l 2),7) 
Legend 1) Avoid direct contact in fittings. Use the appropriate inhibitor. 
Acceptable condition (if any limitations 2) For collector output fittings, take into account the Stagnation temperature of the 
indicated are respected) collector. 
Special study or test necessary 3) The stainless steel grade must resist all types of corrosion. Special attention has to 
Unacceptable condition be paid to welded zones. 
4) Maximum Service temperature of the polymer must exceed the Stagnation 
temperature of the collector. 
1 5) Check the Chemical compatibility between absorber and fluid. 
/ 6) Th’ IS condition effectively excludes galvanized steel. 
7) Polymer used must avoid Oxygen diffusion. 
NOTE - “No xxx” means that the amount of “xxx” shall not be detectable by usual 
laboratory analytical equipment. 
3 lSO/TR 10217 : 1989 (E) 
Table 2 - MateriaVfluid combinations for open Systems 
Absorber 
material 
Aluminium 
Galvanized 
steel Drinkable 
water Aqueous fluid (with or without addition of glycol) Pipes and fittings materials 
With 
Untreated Velocity 
PH Temp. Organic 
fluid Galv. 
inhibitors m/s OC Copper Steel steel Polymer 
\ / 
< 1,22 > 5 
< 9 no H,O l ” l 2’ 
\ I 
> 8 6) 
< 12 < 55 no H,O l 2’ 
Steel > 8 
< ‘f83 < 12 no H,O l 2’ 
Stainless l 3),7) l 3’ l 3’ 
steel Cl- GOppm Cl- < 150 ppm Cl- <50 ppm l 2’ 
\ , 
Cl- < 100 ppm Cl- < 100 ppm 
Copper so4- - < 150 ppm S04- - < 150 ppm <1,22 > 5 l 2) 
no NH,+ no NH4+ 
Polymer l 4’ l 5’ l 2’ 
Legend 1) Avoid direct contact in fittings. Use the appropriate inhibitor. 
Acceptable condition (if any limitations 2) 
indicated are respected) For collector output fittings, take into account the Stagnation temperature of the 
collector. 
Special study or test necessary 3) The stainless steel grade must resist all types of corrosion. Special attention has to 
Unacceptable condition be paid to welded zones. 
4) Maximum Service temperature of the polymer must exceed the Stagnation 
temperature of the collector. 
5) Check the Chemical compatibility between absorber and fluid. 
6) This condition effectively excludes galvanized steel. 
7) Check safety and health regulations. 
NOTE - “No xxx” means that the amount of “xxx” shall not be detectable by usual 
laboratory analytical equipment. 
4 ISO/TR 10217 : 1989 (E) 
El1 
Pl 
[31 
[41 
[51 
NI 
[71 
[8 Annex A 
(informative) 
Bibliography 
National Bureau of Standards (NBS). Performance cri- 
teria for solar hea ting and cooling s ys tems in commercial 
bui/dings. Prepared for US D.O.E. April 1984. 
Arbeitsgemeinschaft Korrosion e.v. (AKG). Regeln zum 
Korrosionsschutz von Solaranlagen zur Wassererwär- 
mung. Werkstoffe und Korrosion 36, 131-133. 1985. 
AVERY, J.G. and KRALL, J.J. Corrosion prevention and 
fluid main tenance in active solar s ystems : the sta te of 
art. Los Alamos Scientific Laboratory, LA-UR-81 3339. 
1981. 
AFEDES. Recommandations pour Ia realisation d’une 
ins tafa tion solaire dans l’habita t. A p r i I 1978. 
YDING, F. Danish experience and testing of internal cor- 
rosion in the absorber loop of a solar System. Corrosion 
Center ATV, Denmark. (Circulated in CEC/CSTG. June 
1985). 
ASTM E 712-80. Practice for laboratory screening of 
metallic con tainmen t ma terials for use with liquids in 
solar heating and cooling Systems. April 1980. 
ASTM E 745-80. Simulated Service testing for corrosion 
of metallic containment ma terials for use with hea t- 
transfer fluids in solar heating and cooling s ystems. 
August 1980. 
AN DR E, J . N . et al. Corrosion dans /es ins tala tions u tili- 
sant des capteurs solaires. Cahiers du CSTB no 1912. 
January 1984. BI 
HOI 
111 
[12 1 
1131 
n41 
[15 
116 1 BAUCH, R., BROVELLI, M. and WEISBERGER, P. Weather- 
ing of solar thermal colectors. J.R.C. ISPRA Report. 
1982. 
UN 1. lmpian ti solari - Colettori solari a liquid0 criteri di 
omologazione. UNI/DEL 148. August 1984. 
WOZNIAK, S.J. Solar heating Systems for the UK. 
Design, installa tion and economical aspec ts. BRE 
Report. 1979. 
CEC/CTG. CEC solar colector durability study and 
refiabifity inspection study. Circulated in CEC/CTG. 
1983. 
CHEVALIER, J.L. et al. Enquete sur Ie comportement en 
ceuvre des capteurs solaires installes en France. ISES - 
Montreal. June 1985. 
Association francaise de normalisation (AFNOR). 
Recommanda tions concernan t /es essais de labora toire : 
Resistance des metaux a Ia corrosion. Project de fasci- 
cule de documentation NF A 05300. December 1984. 
UEAtc. Directives communes UEAtc pour l’agrement 
des cap teurs solaires a circula tion de liquide. Ja nua ry 
1986. 
ISO 6509 : 1981, Corrosion of metals andalloys - Deter- 
mina tion of dezincifica tion resis tance of brass. 
5 ISO/TR 10217 : 1989 (El 
UDC 697.7 : 697.4 : 620.193 
Descriptors : solar energy, solar heating, solar water heaters, specifications, corrosion. 
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