Practical aspectsof atmospheric corrosion

Trends, experiences from Europe,

experiences from Asia/Africa

Policy aspects, costs

History of evidence of effectsof air pollutants on materials

• In London an edict was issued in 1306 banning the use of 'sea-coal' as this is particularly high in chlorine

• Since the industrial revolution soiling and degradation of buildings in urban areas has been noticeable and often attributed to the effects of air pollution

• Systematic laboratory exposures in by Vernon in the 1930’s revealed the importance of SO2

• Field exposures in Germany by Schikorr in the 1940’s revealed the practical importance of SO2

• Field exposures in Nigeria by Ambler and Bain in the 1960’s revealed the practical importance of chlorides

• Field exposures within the Convention on Long-Range Transboundary Air Pollution (CLRTAP) lead to dose-response functions in the 1990’s

Zinc, Stockholm (Vanadis)

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1940 1950 1960 1970 1980 1990 2000

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-2

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SO

2 / µ

g m

-3

Zinc

SO2

Steel, Kopisty (Czeck Republic)

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1960 1970 1980 1990 2000

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SO

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Steel

SO2

Corrosion trend

0%

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1987 1989 1991 1993 1995 1997 1999 2001 2003

Corr

osio

n r

ela

tive 1

98

7

Steel

Zinc

Limestone

Gas concentration trend

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Gas c

once

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.

O3

NO2

SO2

ICP Materials - Test sites

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9-11

17-20

621 2425

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3028

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1413

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39 (29) test sites in 12 (15) European countries and in the United States and Canada

List of test sitesNo Name Country Type

1 Prague-Letnany Czech Republic Urban2 Kasperske Hory Czech Republic Rural3 Kopisty Czech Republic Industrial4 Espoo Finland Urban5 Ähtäri Finland Rural6 Helsinki-Vallila Finland Industrial7 Waldhof-Langenbrügge Germany Rural8 Aschaffenburg Germany Urban9 Langenfeld-Reusrath Germany Rural

10 Bottrop Germany Industrial11 Essen-Leithe Germany Rural12 Garmisch-Partenkirchen Germany Rural13 Rome Italy Urban14 Casaccia Italy Rural15 Milan Italy Urban16 Venice Italy Urban17 Vlaardingen Netherlands Industrial18 Eibergen Netherlands Rural19 Vredepeel Netherlands Rural20 Wijnandsrade Netherlands Rural

No Name Country Type

21 Oslo Norway Urban22 Borregard Norway Industrial23 Birkenes Norway Rural24 Stockholm South Sweden Urban25 Stockholm Centre Sweden Urban26 Aspvreten Sweden Rural27 Lincoln Cathedral United Kingdom Urban28 Wells Cathedral United Kingdom Urban29 Clatteringshaws Loch United Kingdom Rural30 Stoke Orchard United Kingdom Rural Industry31 Madrid Spain Urban32 Bilbao Spain Industrial33 Toledo Spain Rural34 Moscow Russian Federation Urban35 Lahemaa Estonia Rural36 Lisbon Portugal Urban37 Dorset Canada Rural38 Research Triangle Park USA Rural39 Steubenville USA Industrial

Bronze corrosion, SO2 and NO2 concentrations 1987-1995

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m-3

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NO

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m-3

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Mas

s lo

ss

/ g

m-2

Site number

Important pollution parameters

asheltered onlybunsheltered only

Material SO2 NO2 O3 H+ Cl- Carbon steel x xWeathering steel xZinc x xAluminium x xCopper x x xCast bronze x x xNickela x (x)Tina x (x)Alkyd/galvanisedb xSilicon alkyd/steelb xSandstone x xLimestone x xGlass x x x

Model for multi-pollutant impact and assessment of threshold levels for cultural heritage

Interaction of atmospheric pollutants,meteorological conditions and deposition mechanisms in

the process of atmospheric corrosion

Filled fields ( ): MULTI-ASSESSUnfilled fields: ICP Materials

13

5

7 41

8

13

15 16

14

2123

44

2624

46

27

3133

36

34

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43

5049

10

0.0

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1.0

1.5

2.0

2.5

HNO3

HNO3 concentration

Important parameters in the multi-pollutant situation

Material T Rh SO2 NO2 O3 HNO3 PM10 Rain pH

carbon steel X X X X X X

zinc X X X X X X

copper X X X X X X

bronze X X X X X X

limestone X X X X X X

glass X X X X

Comparison of corrosivity of HNO3 and SO2+O3 in laboratory exposure

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Zn Cu Csteel

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ensi

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m-2

d-1

(10

0 p

pb

)-1

HNO3 SO2+O3

Mapping

T Rh Rain SO2 pH

Corrosion = f(T, Rh, Rain, SO2, pH)

Base maps

Corrosion map

Map of corrosion rate of bronze in Germany

Poland

Germany

Czech Republic

Source:Federal Environmental Agency, Berlin, Germany

Acceptable and tolerable levels, target levels and limit values

• The acceptable level is the maximum level at which an acceptable response occurs. The acceptable response should be based on technical and economic considerations.

• The tolerable level is the maximum level at which a tolerable response occurs. The tolerable response should be based on experiences from restoration / maintenance work for cultural heritage objects.

• A target level is a specified level in a given context which should not be exceeded.

• A limit value is a target level that is legally binding.

Tolerable corrosion and pollution

Tolerable pollution levels in the multi-pollutant situation

Definition of a tolerable corrosion rate, Kt, depending on use and material, implicitly defines a tolerable multi-pollution situation, which can be reached by reducing one or several of the multi-pollutants:

Kt= fdry(T, RH, [SO2]t, [HNO3]t, ...)

+ fwet(Rain[H+]t)

Recent information on effects-based approaches for the Protocol reviews

Table 4.0 Effects, important parameters and proposed target levels for materials Effect

Material

SO2 HNO3 PM Tolerable effect

Target SO2 levela

Target PM10 level

Zinc X X 1.1 µm year-1 Corrosion Carbon steel X X 20 µm year-1 10 µg m-3 Limestone X X X 8 µm year-1 Painted steel X 35% loss of Soiling White plastic X reflectance 15 µg m-3 Limestone X in 10-15 years athis level will protect about 80% of the areas. For a complete protection, levels of N-pollutants, especially HNO3 also need to be considered.

Source: MULT-ASSESS Publishable final report, www.corr-institute.se/MULTI-ASSESS

Air Quality Directive 99/30/EC

SO2 NO2 PM10

Urban zones – health effects

Hourly limit value 350 200

Daily limit value 150 50

Annual limit value 40 40

Rural areas - ecosystems

Annual limit value 20 30

Limit values of pollutants, µg m-3

Assessing corrosion costs

Division into pollutionstrata

Materials inventoryand inspection ofphysical damage

Damage functions

Estimated change inservice life

Maintenance/Replacement cost

Estimated economicdamage

Corrosion costs

Specification of a level of corrosion attack where replacement or maintenance is necessary makes it possible to calculate the lifetime, t:

K = fdry(T, RH, [SO2], t) + fwet(Rain[H+], t)

Stock at risk + lifetime Corrosion costs

Sandstone

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Time [years]

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essi

on

[ m

]

1000 m, 78 years

5000 m, 456 years

Critical thickness for technical objects ornaments and inscriptionsRcrit = 5 mm = 5000 m Rcrit = 1 mm = 1000 m

Estimation of stock at risk

• Inspection (Individual building)

• Building Registers (District/City)

• Identikits (National)

• Allocation to census data (Regional)

Stock at risk of galvanised steel in

Germany in m2/km2

Yearly corrosion cost of galvanised steel in

Germany due to pollution (DM/km2)

Reduction of costs due to decreased corrosion damage after execution of the 2nd sulphur protocol (US$·106)

Rural areas Urban areas Total

Eastern Europe 3 700 2 100 5 800

Western Europe 3 000 700 3 700

Total 6 700 2 800 9 500

Quantification of costs and benefits for cultural heritage

Rock Carving in Tanum, Sweden

• Difficult to express in monetary terms the loss of objects of cultural heritage

• Indirect method for calculation of costs- willingness to pay (contingent valuation method)

• Direct benefits (reduced maintenance etc)

• Indirect benefits (incomes from tourism, increased employment etc)

Evidences of high corrosion rates

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Results from Europe not transferable

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ICP Materials (Europe)

RAPIDC/Corrosion (Asia and Africa)