SIST-TR CR 14244:2004
(Main)Durability of wood and wood-based products - Recommendations for measurement of emissions to the environment from treated wood in service
Durability of wood and wood-based products - Recommendations for measurement of emissions to the environment from treated wood in service
This CEN Report is intended to stimulate discussion of the test parameters and the test methodologies to achieve a consensus of opinion. This should allow test methods for emissions from preservative treated wood to be prepared and tested before they become standards. The standards will allow competent authorities and manufacturers of wood preservatives to comply with the requirements of the Biocide Products Directive(BPD.)
Durability of wood and wood-based products - Recommendations for measurement of emissions to the environment from treated wood in service
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TR CR 14244:2004
01-januar-2004
Durability of wood and wood-based products - Recommendations for
measurement of emissions to the environment from treated wood in service
Durability of wood and wood-based products - Recommendations for measurement of
emissions to the environment from treated wood in service
Ta slovenski standard je istoveten z: CR 14244:2001
ICS:
71.100.50 .HPLNDOLMH]D]DãþLWROHVD Wood-protecting chemicals
79.020 Postopki v tehnologiji lesa Wood technology processes
SIST-TR CR 14244:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST-TR CR 14244:2004
---------------------- Page: 2 ----------------------
SIST-TR CR 14244:2004
CEN REPORT
CR 14244
RAPPORT CEN
CEN BERICHT
October 2001
ICS
English version
Durability of wood and wood-based products -
Recommendations for measurement of emissions to the
environment from treated wood in service
This CEN Report was approved by CEN on 6 July 2001. It has been drawn up by the Technical Committee CEN/TC 38.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. CR 14244:2001 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
Contents
Foreword.3
Introduction .4
1 Scope .5
2 Framework of cases for determination of needs for emission test methods.5
3 Review of methods of measurement of emissions from preservative treated wood .6
4 Characteristics of realistic emission test methods.11
Bibliography .14
2
---------------------- Page: 4 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
Foreword
This document has been prepared by CEN /TC 38, "Durability of wood and wood-based products", the secretariat
of which is held by AFNOR.
The status of this document as CEN Report has been chosen because the most of its content is a review of
methods of measurement of emissions from preservative treated wood in order to stimulate the discussion of the
test parameters and the test methods for emissions to be retained.
3
---------------------- Page: 5 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
Introduction
The regulatory control of biocides and biocidal products (as defined under the UE Directive 98/8/EC, including
wood preservatives, requires increasing amounts of environmentally related information on which to base
decisions.
In the case of wood preservatives (product type 8) this includes the provision of data concerning wood preservative
treated articles.
This data is used to assess whether there is an unacceptable environmental impact likely to arise from the use of
the treated timber product.
Such a risk assessment has to consider potential releases to all environmental compartments, namely air, soil,
surface water, groundwater and sediment.
Many uses of wood preservative products are intended to extend the natural durability based expectation of service
life, sometimes in the order of several decades.
It is therefore necessary to have a means of determining not only absolute values for potential emissions to the
environment but perhaps more importantly the fluxes, or rates of emission during the course of time. They should
be representative.
That is to say they should represent the emissions from in service sized pieces of treated wood.
Flux rates and profiles can then be inserted into mathematical models usually based on defined scenarios .
Such determinations of emission rates will also be invaluable in the development of new products because they will
enable the researcher to identify early in the development of the product whether there are potential problems with
the product in its areas of intended use.
It is quite impractical to mimic all of the biotic and abiotic factors present the natural environment in the laboratory.
It has to be decided if a means can be found which will take into account as many as possible of these factors
together with the large variation in climate and socio-economic factors present in Europe. Is it possible to conceive
of a “surrogate” environment into which to determine emissions?
If it is believed that there is a potential for creating EN standards in this area it is vital that the methods can be
reproduced in any suitably equipped laboratory, whether government, institute or industry. The methods should
also not be costly, but must be cost effective.
Having produced an emission this should then be characterised. This might be through chemical analysis of the
active substances, substances of concern and relevant metabolites; or by some other tests which can indicate
ecotoxicological effects, for example so-called “soup testing”. The next steps would be to identify the environment
‘belonging’ to the treated component and to characterise the physical-chemical behaviour of the active substances,
substances of concern and relevant metabolites in order give an answer about their bioavailability in a given
environment.
These aspects are being considered by other expert groups in the EU and the OECD and should not be considered
part of the remit for CEN/TC 38 to produce standards.
Any proposed standards should also take into consideration of the Technical Guidance Documents (currently being
revised) in place for the Biocidal products Directive (98/8/EC), and the New and Existing Substances Regulations
4
---------------------- Page: 6 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
1 Scope
This CEN Report is intended to stimulate discussion of the test parameters and the test methodologies to achieve a
consensus of opinion. This should allow test methods for emissions from preservative treated wood to be prepared
and tested before they become standards. The standards will allow competent authorities and manufacturers of
wood preservatives to comply with the requirements of the Biocide Products Directive(BPD.)
2 Framework of cases for determination of needs for emission test methods
The following matrix has been established taking into account different documents and works (see [2] to [7]
included).
The aim is to try to link the different end-use categories for treated timber in service, with the Biological Hazard
Classes on one hand and the exposed environmental compartment on the other hand; through this, it is possible to
list the specific cases of emissions from treated timber to the environment (see Table 1).
Table 1 — Specific cases of emissions from treated timber to the environment
Targets Biological Use categories and Exposed Emission data needed First Exposed
Hazard typical scenarios Environmental Non targets
Classes Compartment
Insects HC 1 Internal non structural Indoor Air Emission to indoor Air Human
Bedroom floor
Insects + HC 2 Internal structural Indoor Air Emission to indoor Air Human Environment
Fungi Roofing timber Indoor air organisms
(Bats)
Insects + HC 3 External above ground and Soil by run-off rain Leaching by rain water Environment
Fungi above fresh-water water Soil organisms
Leachate migration into
House cladding Fresh water by run-off Fresh water organisms
soil /surface water
Fence rails rain water
Jetty planks
Insects +HC 4 External in ground contact Soil by run-off rain Leaching by rain water + Environment
Fungi Transmission Pole water Leachate migration into Soil organisms
a Fence post Soil by direct contact soil + Direct emission into
soil
External in freshwater Fresh water by run-off Leaching by rain water + Environment
contact rain water Direct emission into water Fresh water organisms
b Jetty in a lake Fresh water by direct Ground water
Poles contact
Sheet Pilings
Insects + HC 5 External in seawater Sea water by run-off Leaching by rain water + Environment
Fungi + contact rain water Direct emission into sea
Sea Water organisms
Marine water
Sea water by direct
borers
contact
There are two ways to approach the question of the need for emission data to feed in the exposure assessment
calculations in the different scenarios.
The first approach would be to consider globally the emission from the commodity to the environment without any
differentiation of all the mechanisms. This would mean to have one test method for each of the commodities listed
in the reference scenarios ; or, if it is possible to define a worst case scenario for each use category or a model
case, then one test method would be needed for each of the use categories where the conditions are strongly
different ; only may be the cases of HC 1 and HC 2 could be combined (emissions from wood to indoor air) , as well
as HC 4 b and HC 5 where the difference is only the kind of water. This approach looks rather difficult to handle in
a systematic way of producing emission data, as the list of tests needed might change if scenarios are revised.
5
---------------------- Page: 7 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
The second approach would be to consider each possible mechanism of emission to obtain elementary emission
data, and then to combine these (sum up) to calculate the global emission of one commodity to a given
environmental compartment in a scenario.
In this second approach, the list of types of emission data needed is the following :
emission from treated wood to indoor air ;
leaching from treated wood by rain water ;
rain water leachate migration into soil/water ;
direct emission from wood into soil/ground water ;
direct emission from wood into water (fresh water or sea water).
3 Review of methods of measurement of emissions from preservative treated wood
3.1 General
Methods are required for the measurement of emissions from preservative treated wood in service. This document
reviews a number of methods which have been used to measure emissions from preservative treated wood under
laboratory conditions. These methods do not include tests using small specimens or sawdust, or for measuring
emissions from wood during drying after treatment.
The methods are for wood in service in biological HC 2 to HC 5, with exposure to the environmental compartments
of air, soil, ground water beneath soil, fresh water and sea water.
3.2 Air
It is possible that treated wood used in a building could affect air, indoor air, and treated wood outside buildings
could affect outdoor air. The Existing Substances Directive uses a value of 0,01 Pa as the vapour pressure
threshold. Below this vapour pressure a substance is not considered to be volatile and emissions to air are not
considered in the risk assessment. If the substance has a vapour pressure greater then 0,01 Pa, the substance is
considered sufficiently volatile to evaporate and produce a concentration in air. The effect of that concentration
should be considered in a risk assessment. The concentration is used in an equation which predicts deposition on
to surface water and the resulting concentration in the surface water (Predicted Environmental Concentration)
assessed for the risk to aquatic organisms by dividing the PEC by the PNEC (Predicted No Effect Concentration)
from an ecotoxicological test organism (e.g LD Daphnia).
50
If the PEC / PNEC ratio is greater than 1, there is a potential environmental risk and the tiered approach allows the
PEC to be measured, rather than calculated. As it is not possible to measure the concentration in surface water
which is solely emitted from treated wood, and the emissions from treated wood are likely to be affected by many
parameters, the actual emission from treated wood could be measured.
The ‘Metre cube box’ method has been used for the measurement of formaldehyde emission from wood. The
principle of the test is realistic in that treated wood could be placed in the chamber at a defined temperature and air
at a defined flow rate can be passed over it. Any volatile materials at the temperature of the test will evaporate and
pass out of the chamber. The air will then have to be tested for its environmental effects. If the active ingredient can
be analysed, then it will have to be extracted from the air and chemically analysed. The result can be converted to
2
an amount of active ingredient emitted in mg/m /day.
If the active ingredient cannot be analysed, or all of the substances emitted from the wood need to be assessed for
their environmental effect, and not just the active ingredient of the wood preservative, then the outlet air will have to
be used in a test which measures the environmental effect of air. It is probably outside the scope of CEN TC/38
Working Group 25 to suggest a suitable test. The OECD Biocides programme is considering methods of
ecotoxicological testing and are considering this issue.
6
---------------------- Page: 8 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
Note that the vapour pressure of 0,01 Pa is the vapour pressure of the components in the dry wood and not of the
components in the treating solution. It is unlikely that any of the components of current wood preservatives used
indoors have components which have a vapour pressure in dry wood of greater than 0,01 Pa, so this test is unlikely
to be required in support of a wood preservative to comply with the data requirements of the BPD.
Meyer and Boehme (1997) (see |13]) determined formaldehyde emission from solid wood using a specially
3
designed chamber of 1 m . During testing, the temperature was (23 ± 1) °C and the relative humidity was
-1
(45 ± 5) %. The air exchange rate was fixed at 1 h . The chamber was loaded with four solid wood samples
2
measuring 500 mm by 250 mm by 20 mm, giving a total surface area capable of emission of 1 m (neglecting the
edges). Thus, the ratio of air exchange rate to loading was 1. These test conditions were in accordance with
specific provisions (Chemikalien –Verbotsverordnung, 1993) (see [9]). The sampling period was 50 min and the
test ran for 15 days. Concentrations of 2g/kg to-9 g/kg formaldehyde were measured.
Van Eetvelde and Stevens (1993) (see [18]) used a 7,9 l column containing a specimen of meranti 55cm x 6cm x 1
cm, coated with preservative, and exposed for 48 h or 96 h to an air flow rate of 2 l/min. The ratio of wood volume
to air volume is 1:24 and the wood surface area to air volume is 1: 10. Air changes are 16 changes per hour. The
2
emission rate for dichlorofluanid applied in a primer-type formulation at 80 g/m after 48 h drying, emitted 2,6
2 2
/h over the first 24 h at 40 °C. This is equivalent to an emission rate of 0,06 mg/m /day.
3
Wu and Milota (1999) (see [20]) used a 1m laboratory kiln connected to two sets of condensers to cool the
exhaust air and to collect water. The quantity of wood (Douglas fir) was 20 boards, 17,.3 cm long, 42mm x 147 mm
cross section. The temperature and humidity were chosen to simulate kilning schedules at temperatures from
71,1 °C to 93,3 °C using air at ambient temperature and humidity flowing at 2l/min for 48 h. Emissions were 0,70 to
2
0,84 g/kg oven dry wood, equivalent to 0,00024 mg/m /day. The ratio of wood volume to air volume is 1:46, and
the wood surface area to air volume is 1: 63. Air changes are 0,12 changes per hour.
3
The European Wood Preservative Manufacturers Group (EWPMG )has proposed a test using a 1 m box . The
-1
method uses (23 ± 1) °C and a relative humidity of (45 ± 5) %. The air exchange rate is 1 h . The chamber is
2
loaded with wood having a surface area of 1 m so the ratio of air exchange rate to loading is 1. The rate of
2
emission in mg/m /day should be determined over 0 day to 10 days, and 10 days to 100 days.
In the Organisation for Economic Co-operation and Development (OECD) emission scenario the ratio of wood
2 3 3
surface area (205 m ) to receiving compartment volume in the roof (227 m ) is 1:1,1. If the 1 m box is acceptable,
the test parameters to be decided are wood dimension and surface area, air temperature and humidity, air changes
per hour, duration of test and sampling times.
A research report in the context has been published in "UBA-Texte (51-99)" as "BAM-Forschungsbericht :
Entwicklung eines standardisierbaren Prüfverfahrens zur Bestimmung des Eintrages von
Holzschutzmittel-Wirkstoffen aus behandeltem Holz, Altholz und daraus hergestellten Holzwerkstoffen in die Luft".
The report includes the results of emission measurements with regard to Lindan, Furmecyclox, Dichlofluanid,
Permethrin, Tebuconazol, Propiconazol taking into account also different types of emission test chambers. Extracts
of this report are also published in [23], [24] and [25].
3.3 Above Ground
The environmental risk of preservative treated wood in service out of ground contact is considered to be soil or
surface water. For example the components of a fence or deck which are above soil but not in contact with the soil,
and the components of a jetty or fisher cabin which are above water, but not in contact with it.
Stilwell and Gorny (1997) (see[16]) measured the amount of Cu ,Cr and As beneath seven treated decks in service
and compared the concentrations with soils samples not beneath the deck. The decks ranged in age from
4 months to 15 years. The average contents (mg/kg) in soil beneath decks were Cu 75 mg/kg , Cr 43 mg/kg, As
76 mg/kg, and the control soils were Cu 17 mg/kg, Cr 20 mg/kg and As 4 mg/kg. The Cu, Cr and As emissions can
be calculated from the data in the paper (Table 2). The emission is higher in the first four months, and decreases
with time so that the Cu, Cr and As levels beneath the 15 years deck are close to background levels. The level of
2
emission is less than 4 mg/m /day.
7
---------------------- Page: 9 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
Table 2 — Cu, Cr and As emissions calculated from Stilwell and Gorny (1997), (see [16])
Years in Minimum : Minimum in soil beneath deck Maximum : Maximum in soil beneath
service minus minimum in control soil deck minus maximum in control soil
2 2
(mg/m /day) (mg/m /day)
Cu Cr As Cu Cr As
0,3 2,,05 0,68 0,18 9,82 1,60 3,54
2 0,38 0,10 0,12 1,64 1,85 2,94
5 0,27 0,03 0,43 1,58 0,52 1,24
7 0,23 0,09 0,41 1,08 0,90 3,18
7 0,16 0,09 0,54 2,55 1,17 2,07
8 0,39 0,10 0,40 3,28 1,12 2,95
15 0,03 0,02 0,02 0,15 0,06 0,35
Cooper and Ung (1997) (see [10]) measured Cu ,Cr and As in the water collected from fence and deck units. The
6” x 1” fence boards and 2” x 6” decking were treated with 2% CCA-C, fixed at 21 °C or at 60 °C with high humidity.
The boards were leached for 12 cycles of accelerated spray exposure with recirculating water. The concentration of
Cu, Cr and As was measured in the water. The boards were then made up into fence or deck units and exposed
outdoors and above ground to natural weathering. Water running off the units was collected and analysed after
4 months exposure and 2 years exposure. See Table 3. The highest concentration was 2,40 mg/kg Cu from 21 °C
fixed fence boards. After 4 months the highest concentration was 4,91 mg/kg Cu , and after 2 years, the highest
concentration was 3,74 mg/kg Cu from the same fence boards. After 2 years, copper was 0,38 mg/kg to
3,74 mg/kg, Cr 0,2 mg/kg to 1,89 mg/kg and As 0,17 mg/kg to 3,06 mg/kg.
Table 3 — Concentration of Cu, Cr As in spray water and run-off water from CCA treated fence
and deck components and units
Fixation at 21 °C Fixation at 60 °C .High humidity
Cu Cr As Cu Cr As
mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg
Fence
Spray water Concentration 2,40 0,90 1,95 1,38 0,23 1,05
Average Concentration 0 month 4,91 1,16 2,79 5 1,11 2,58
to 4 months
Average Concentration 3,74 1,89 3,06 3,51 1,89 2,80
4 months to 2 years
Deck
Spray water Concentration 1,61 1,37 1,90 1,22 0,64 1,35
Average Concentration 0 month 1,92 ,63 1,68 1,63 0,63 1,51
to 4 months
Average Concentration 0,81 0,47 1,66 0,38 0,2 0,17
4 months to 2 years
The EWPMG have proposed a test using a 5 cm x 5 cm test specimen, 15 cm long. One face is sprayed with water
(75 ml per day, 5 days per week) to simulate rainfall equivalent to 1400 mm rain per year. The run-off water is
collected and analysed, or could be used in ecotoxicological testing.
The effect of light on wood exposed out of ground contact can be important in determining emission rate, and
should be simulated in a laboratory test. These tests did not use artificial light.
8
---------------------- Page: 10 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
The author has used preservative treated panels, 400 mm x 97 mm wide, 20 mm thick, exposed to natural
weathering outdoors. They are exposed vertically, with only the front face open to exposure. A collector beneath
2
the panel collects run-off water. This experimental set up allows the rate of emission in mg/m /day to be
determined over 0 day to 10 days and at intervals. The test ran for 66 weeks. The emission rate appeared to
decline with longer exposure times but there were peaks of emission in periods of high rainfall, several months
after exposure.
The weatherometer is a standardised test for wood exposed out of ground contact and could be adapted to enable
to collection of emissions from treated wood. The important requirement is for a natural and realistic exposure
regime, not an accelerated test which is likely to be more severe than experienced by wood in service.
The test parameters which would need to be decide are the dimensions of the test specimen, how realistic rainfall
would be applied to it, defining what is realistic rainfall in terms of droplet size, frequency and duration. Also the
need for drying periods and the duration of wetting and drying periods, and how light can be simulated realistically.
2
The rate of emission in mg/m /day should be determined over 0 day to 10 days, and 10 days to 100 days.
Note the variability of the results in the published papers. The test protocol should allow a means of calibrating the
test method and allowing for variability in test results. Alternatively, a range would have to be used in subsequent
th
risk assessments. The use of ranges of values (mean, median, 90 percentile etc) as emission values, rather than
2
one value in mg/m /day still needs to be addressed, although not as part of these methods.
3.4 Soil Columns
Once an emission has been clected from wood above ground, its effect on soil can be determined. Although this is
a major requirement of the BPD, it may be outside of the scope of these methods to standardise the testing of
emissions in soil. Perhaps reference could be made to existing standards (e.g. OECD 106 for measuring soil
absorption, or ecotoxicological test using earthworms). However, the effect of wood preservatives in soil have been
investigated, usually using soil columns or lysimeters.
Peek, Klipp and Brandt (1993) (see [14]) used soil which had passed through a 2mm sieve, in a soil column 25 mm
diameter, 250 mm deep, wetted daily with 50 ml of demineralised water.
Holland and Orsler describe two techniques for determining the absorption of wood preservatives in soil. The
method described in OECD guidelines uses 3 g of soil and 15 ml of preservative agitated gently and sampled after
1 h, 2 h, 3 h, 24 h and 96 h. The 1 ml liquid samples were analysed to determine the amount in solution and by
difference, the amount absorbed by the soil. The Thin-Layer Chromatography (TLC) plate technique uses glass
slides coated with a slurry of soil and water and allowed to dry. One end is dipped in the preservative solution and
the plate removed after the liquid front had moved 165 mm. The soil on the slide at different positions could be
sampled and analysed.
Melcher and Peek (1998) ( see [12]) have reviewed a number of soil column (lysimeter) tests with wood
preservatives. They conclude that the column should have a minimum diameter of 5 cm to avoid wall effects and
the soil depth should not exceed 30 cm to ensure ‘justifiable’ test durations and a minimal use of material. The
conclude that percolation with leachates containing preservatives supplies values which are sufficiently exact.
The EWPMG have proposed a soil column method using an 11 cm column, 30 cm deep. The preservative treated
5 cm x 5 cm test specimen, 15 cm long is suspended above the soil column. One face of the specimen is sprayed
with water (75 ml per day, 5 days per week) to simulate rainfall equivalent to 1400 mm rain per year. The run-off
water is allowed to drip onto the soil. Any water which passes through the soil is collected and analysed, or could
be used in ecotoxicological testing. The collected water is considered to be ground water.
The test parameters to be decided are the percolation frequency and duration, the amount of liquid added at each
time, the ratio of wood to soil volume, soil water content, the choice of soil and the need for a number of different
soil types.
9
---------------------- Page: 11 ----------------------
SIST-TR CR 14244:2004
CR 14244:2001 (E)
3.5 Soil
The environmental risk of preservative treated wood in service in ground contact is considered to be soil and
ground water, e.g. the part of a fence post or transmission pole which are is contact with the soil.
Sinclair, Smith, Bruce and Staines (1993) (see [15]) used a 2 m length of pole (which had been remedially treated
with a chromium containing preservative) in a grass covered soil bed 55 cm x 108 cm, 55 cm deep, containing
buried perforated pipes for leachate collection. Rainfall was from a spray head atomiser 165 cm above the soil, and
15 cm above the pole. There were nine applications of rain, totalling 370,5 l over 40 days. This amount of water is
equivalent to 62 mm of rainfall over the soil bed surface. They reported that the total chromium content of the
leachate was approximately 50 mg. Assuming a pole diameter of 30 cm, this is equivalent to an emission to
2
groundwater of 0,61 mg/m /day. This value is for an unfixed, surface applied preservative exposed to unrealistically
high rainfall.
The EWPMG have proposed a method and initial experiments using the protocol have been carried out. Results
have been obtained and submitted to scrutiny in the Pilot Scheme of the BPD. The principle is to have a
commercial dimension, commercially treated piece of wood, buried to half its length in moist soil. Water is sprayed
on the surfaces above soil with the quantity, frequency and intensity of rain. Water which passes through the soil
can be collected and analysed, or it can be subjected to direct ecotoxicological test. The test can be run for
months, but the 0 day to 10 day period, 10 day to 30 day period and the 30 day to 100 day and after 100 day
periods are required to determine the shape of the emission curve and to allow PEC values to be calculated for
2
comparison with acute and chronic PNEC values. The emission rate in mg/m /day can be calculated. The soil can
be analysed at the end of the experiment to estimate absorption, and it could be used in a standardised soil
ecotoxicological test (e.g. OECD earthworm test).
NOTE That the above ground portion of the post is not sprayed with water, so the only route into the soil is from the portion
of the post below ground.
The test parameters to be decided are similar to the above ground test : the dimensions of the test specimen, the
ratio of wood to soil volume, soil water content, the choice of soil and the need for a number of different soil types,
how realistic rainfall would be applied to the system, defining what is realistic rainfall in terms of droplet size,
frequency and duration. Also to be decided are need for drying periods and the duration of wetting and drying
periods, and how light can be simulated realistically.
3.6 Fresh water
The environmental risk of preservative treated wood in service in water is considered to be fresh water, e.g. the
part of a pile supporting a jetty which is contact with the water, or the leaching of preservatives from a building (e.g.
boathouse of jetty) without direct contract with the water.
Warner and Solomon (1990) ( see [19]) used CCA pressure treated jack pine boards, 1,5 m long, 13 cm wide and
25 mm thick. Six boards were selected from newly treated wood, cut in half and one exposed to natural weathering
2
for one year. From each board, six 5 cm sections were cut. These were submerged in a tank (with a lid) containing
5 l of leaching solution, and air was bubbled through the leaching solution (water, water buffered to pHs from 3,5 to
8,5, citric acid/sodium hydroxide, borax/ hydrochloric acid buffer or sulfuric acid). The ratio of wood volume to
leaching solution volume is 1:13,3, and the ratio of wood surface area to leaching solution volume is 1:8,3. At
intervals up to 40 days, 15 ml samples were analysed. The highest emission was measured for copper from
2
natural
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.