CREOSOTE TESTED IN A SOIL SOFT ROT TESTCREOSOTE

COST ACTION E22: ENVIRONMENTAL OPTIMISATION OF WOOD PROTECTION

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 by VAN ACKER, Joris ; GHEKIERE, Kristof and STEVENS, Marc Ghent University (RUG), Belgium

Tuusula, Finland, COST Action E22 Workshop, 2-4 June 2002 ‘Current advances in timber protection’

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Objective Creosote formulations are under ‘reconsideration’ and should be tested according to the effectiveness assessment as described in EN 599 The use of both evaporative ageing (EN 73) and leaching (EN 84) alone as pre-conditioning for testing creosote to be used under hazard classes 4 and 5 prevents a valid test to be carried out A range of pre-conditioning systems have been evaluated on their impact on mass loss to identify potential solutions Different types of creosote have been tested according to ENV 807 taking into account the results from this introductory research on adequate ageing systems

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Materials and methods for evaluating ageing systems Creosote types used: - WEI Type B for most pre-conditioning work - WEI Type C for a limited number of ageing systems.

- 5 % creosote solutions aiming at retention levels of 25 kg/m続 in Scots pine sapwood and 15 kg/m続 in beech

Ageing systems: - Evaporation procedures: EN 73; 12 weeks exposure in fume cupboard; vacuum oven - Leaching procedures: EN 84; leaching with agitation (ENV 1250-2); wetting as in ENV 807 - Specimens for Basidiomycetes efficacy testing according EN 113: 1.5 x 2.5 x 5.0 cm

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 80

70

Retention in kg/m³

60

50

40

30

20

10

0 EN 73

12 wks

Vacuum

EN 84

EN 1250

Wetting

EN 73 + EN 84

12 wks + Vacuum + 12 wks + Vac. + 12 wks + 12 wks + 12 wks + EN 84 EN 84 EN 1250 EN 1250 wetting EN 73 vacuum

Pre-condtioning of Scots pine sapwood treated with creosote type B Conditioned

After ageing 1

Before ageing 2

After ageing 2

at 50 °C

at 102°C

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 140

120

Toluene

Xylene

Retention in kg/m³

100

80

60

40

20

0 Pine Type B

Pine Type C

Beech Type B

Beech Type C

Pine none

Beech none

Pine Type B

Pine Type C

Beech Type B

Beech Type C

Pine none

Beech none

-20

Wood species - creosote type Conditioned

After 12 wks

Before ageing 2

After EN 84

at 50 °C

at 102°C

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Results - Discussion on ageing systems - Mass reduction is lower for leaching procedures than for evaporation - 12 weeks in a ventilated room (fume cupboard) prior to a subsequent evaporation (EN 73 or vacuum oven) does not evacuate more - Wood blocks treated with creosote WEI type C show higher residual amounts than type B - Xylene as solvent evaporates less than toluene and should not be recommended for creosote testing - Taking into account mass losses of purely solvent treated blocks 50 to 60 % of the initial creosote retention for respectively type B and type C remain after 12 weeks ventilated room + EN 84 leaching

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Conclusions on ageing systems - Release of volatile components from creosote treated test specimens is reached using a 12 weeks storage in a ventilated cupboard in addition to the ‘conditioning and fixation’ requirements as described in EN 113 - Both EN 73 evaporation and the alternative vacuum oven ageing result in similar gravimetric losses which are higher than a 12 weeks ventilated storage - In order to assess the impact of leaching (EN 84) adequately, it is recommended to precede the leaching by a 12 weeks storage in a ventilated cupboard RECOMMENDED AGEING METHODS For EN 113: 12 weeks air ventilation prior to EN 73 or EN 84 For ENV 807: EN 73 or 12 weeks air ventilation prior to EN 84

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Materials and methods for testing according to ENV 807 1(2) Creosote types used: - WEI Type B - WEI Type C - reference creosote type IV (replacing original WEI Type A).

- creosote solutions aiming at retention levels of 17.5 / 25 / 35 / 50 and 75 kg/m続

Ageing systems: - 12 weeks in ventilated room + EN 84 leaching - EN 73 evaporation (wind tunnel) + EN 84 leaching

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Materials and methods for testing according to ENV 807 2(2) Test specimens: - Wooden stakes measuring 100 mm x 10 mm x 5 mm - Beech and Scots pine sapwood

Soil soft rot testing systems: - According to ENV 807 for 4 periods: 8, 16, 24 and 32 weeks - CC as reference preservative - standard test soil RUG + additional testing of creosote WEI type C in John Innes II - In each test container (60 in total): 1 wood species / 1 creosote / 1 concentration

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Remaining creosote Type WEI B in Scots pine sapwood 80

20

Creosote retention (kg/m続)

15 60 50

10

40 5

30 20

0

Weight gain correction (%)

70

EN73 + EN84 12 wks + EN84 EN73 + EN84 12 wks + EN84

10 0

-5 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 0.0 0.0 3.5 3.5 5.0 5.0 7.0 7.0 10.0 10.0 15.0 15.0 Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Remaining creosote Type WEI B in beech 20

100

15

Creosote retention (kg/m続)

80 70

10

60 50 40

5

30 20

0

Weight gain correction (%)

90

EN73 + EN84 12 wks + EN84 EN73 + EN84 12 wks + EN84

10 0

-5 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 0.0 0.0 5.8 5.8 8.3 8.3 11.6 11.6 16.5 16.5 25.0 25.0 Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Remaining creosote Type WEI C in Scots pine sapwood (series 1) 80

20

Creosote retention (kg/m続)

15 60 50

10

40 5

30 20

0

Weight gain correction (%)

70

EN73 + EN84 12 wks + EN84 EN73 + EN84 12 wks + EN84

10 0

-5 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 0.0 0.0 3.5 3.5 5.0 5.0 7.0 7.0 10.0 10.0 15.0 15.0 Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Remaining creosote Type WEI C in beech (series 1) 20

100

15

Creosote retention (kg/m続)

80 70

10

60 50 40

5

30 20

0

Weight gain correction (%)

90

EN73 + EN84 12 wks + EN84 EN73 + EN84 12 wks + EN84

10 0

-5 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 16 wks 32 wks 0.0 0.0 5.8 5.8 8.3 8.3 11.6 11.6 16.5 16.5 25.0 25.0 Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

20

10

10

5

0

0

Mass loss corrected (%)

15

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

24 wks

30

8 wks 15.0

20

24 wks

40

8 wks 10.0

25

24 wks

50

8 wks 8.0

30

24 wks

60

8 wks 5.0

35

24 wks

70

8 wks 3.5

40

24 wks

80

8 wks 0.0

Creosote retention (kg/m続)

Mass loss of Scots pine sapwood treated with creosote Type IV

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

20

10

10

5

0

0

Mass loss corrected (%)

15

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

24 wks

30

8 wks 15.0

20

24 wks

40

8 wks 10.0

25

24 wks

50

8 wks 7.0

30

24 wks

60

8 wks 5.0

35

24 wks

70

8 wks 3.5

40

24 wks

80

8 wks 0.0

Creosote retention (kg/m続)

Mass loss of Scots pine sapwood treated with creosote Type WEI B

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

20

10

10

5

0

0

Mass loss corrected (%)

15

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

24 wks

30

8 wks 15.0

20

24 wks

40

8 wks 10.0

25

24 wks

50

8 wks 7.0

30

24 wks

60

8 wks 5.0

35

24 wks

70

8 wks 3.5

40

24 wks

80

8 wks 0.0

Creosote retention (kg/m続)

Mass loss of Scots pine sapwood treated with creosote Type WEI C (soil RUG)

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 Mass loss of Scots pine sapwood treated with creosote Type WEI C (John Innes II soil) 80

40

70

35

20 40 15 30

10

20

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

5

24 wks

8 wks 15.0

24 wks

8 wks 10.0

24 wks

8 wks 7.0

24 wks

8 wks 5.0

-5 24 wks

0 8 wks 3.5

0

24 wks

10

8 wks 0.0

Creosote retention (kg/m続)

25 50

Mass loss corrected (%)

30

60

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 Mass loss of beech treated with creosote Type IV 60

100

55

90

50

80

40

60

35

50

30 25

40

20

30

Mass loss corrected (%)

70

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

15 20

10

24 wks

8 wks 25.0

24 wks

8 wks 15.0

24 wks

8 wks 10.0

24 wks

8 wks 8.0

0 24 wks

0 8 wks 5.0

5

24 wks

10

8 wks 0.0

Creosote retention (kg/m続)

45

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 Mass loss of beech treated with creosote Type WEI B 60

100

55

90

50

80

40

60

35

50

30 25

40

20

30

Mass loss corrected (%)

70

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

15 20

10

24 wks

8 wks 25.0

24 wks

8 wks 16.5

24 wks

8 wks 11.6

24 wks

8 wks 8.3

0 24 wks

0 8 wks 5.8

5

24 wks

10

8 wks 0.0

Creosote retention (kg/m続)

45

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 Mass loss of beech treated with creosote Type WEI C (soil RUG) 60

100

55

90

50

80

40

60

35

50

30 25

40

20

30

Mass loss corrected (%)

70

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

15 20

10

24 wks

8 wks 25.0

24 wks

8 wks 16.5

24 wks

8 wks 11.6

24 wks

8 wks 8.3

0 24 wks

0 8 wks 5.8

5

24 wks

10

8 wks 0.0

Creosote retention (kg/m続)

45

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807 Mass loss of beech treated with creosote Type WEI C (John Innes II soil) 60

100

55

90

50

80

40

60

35

50

30 25

40

20

30

Mass loss corrected (%)

70

EN73 + EN84 12wks + EN84 EN73 + EN84 12wks + EN84

15 20

10

24 wks

8 wks 25.0

24 wks

8 wks 16.5

24 wks

8 wks 11.6

24 wks

8 wks 8.3

0 24 wks

0 8 wks 5.8

5

24 wks

10

8 wks 0.0

Creosote retention (kg/m続)

45

Treating concentration and period

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Results - Discussion on soil soft rot testing 1(2) - Creosote treatments at retentions of 75 kg/m続 change the weight 5% for creosote type B and 10 % for creosote type C after ageing - The retained or residual amount of creosote is very similar for both ageing methods.

- Only at high retention levels with creosote type C there is some distinction between both ageing systems. Variability is also higher and a longer period in the test chamber (32 weeks versus 16 weeks) still induces some extra loss of volatiles.

- Mass loss of creosote treated pine at 75 kg/m続 is approximately 5% after 24 weeks of testing.

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Results - Discussion on soil soft rot testing 2(2) - Creosote treated beech specimens show the same pattern over time in mass loss as control specimens at levels up to 25 kg/m続.

- All creosote treated beech specimens show mass loss of 10 % and higher even at 8 weeks testing.

- Testing of beech treated with creosote type C in John Innes II soil showed lower mass loss figures but still over 5 % at the highest retention for test periods over 16 weeks.

- Since mass losses were below 10 % even after testing control Scots pine sapwood in the John Innes II soil no valid results can be obtained for that particular test.

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Conclusions on soil soft rot testing 1(2) - Evaluation of creosote in relation to the system described in EN 599 is impossible since mass losses recorded are above critical values.

- There is no indication that at high retention level the toxic limit for creosote is approached especially when focussing on beech - It can be assumed that creosote is detoxified allowing soft rot decay to progress and decay the small section mini stakes within the set test period.

- The fact that test soils in ENV 807 contain natural variability in microorganisms allow both detoxifying and decaying organisms to be active.

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Conclusions on soil soft rot testing 2(2) - This result is however not in contradiction with the excellent performance of creosote in practical application.

- Mechanisms of detoxification followed by decay progress slowly inwards from the outer zone of treated material. The large dimensions of treated material and the mobility of creosote both towards the detoxified zones and into some surrounding soil allows a time span to failure leading to over 50 year performance.

- The fact that creosote is detoxified by soil inhabiting microorganisms might lead to the provocative conclusion that creosote could well be one of the most modern wood preservatives....

GHENT UNIVERSITY

CREOSOTE TESTED IN A SOIL SOFT ROT TEST ACCORDING TO ENV 807

Acknowledgement This research was carried out as part of an European research project FAIR-CT98-3933: 'Integrating the processes involved in the production of creosoted utility poles’ (WOODPOLE).

Financial support was given by the European Commission as part of the Agriculture and Fisheries Programme.

GHENT UNIVERSITY