specifying treated wood for industrial uses

Date:

Location:

Date:

Location:

Specifying Treated Wood For Industrial Uses.

Paul Morris, PhD

Research Leader:

Durability and Building Enclosure

Advanced Building Systems Dept.

Presentation Content Pressure treatment process Specifying wood for industrial use Overview of CSA O80 Series: Wood Preservation Understanding Use Categories 1 through 5A Products and Use Categories for specific exposures Options for preservative Appropriate and inappropriate preservative substitution Pre- and post-treatment conditioning Comments on species for strength, stability and treatability BCMoFLNRO Process Specification Third party quality assurance Handling of treated wood to maximize durability Long term performance

Pressure Treatment Process

Atmospheric -

Pressure

Roll in Poles on Cart

Atmospheric -

Pressure

Apply Vacuum to Remove Air From Wood

Atmospheric -

Pressure

Fill With Preservative Solution

Atmospheric -

Pressure

Apply Pressure

Atmospheric -

Pressure

Continue to Apply Pressure

Atmospheric -

Pressure

Stop Pressure

Atmospheric -

Pressure

Release Pressure

Atmospheric -

Pressure

Drain Solution

Atmospheric -

Pressure

Apply Vacuum to Remove Excess Solution From Wood Surface

Atmospheric -

Pressure

Release Vacuum

Atmospheric -

Pressure

Remove Poles

Atmospheric -

Pressure

Accelerated Fixation

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Specifying Wood for Industrial Use Plan well in advance.

• No stocks of industrial treated wood • Wood has to be ordered, then fitted into treatment schedule

Select treater knowledgeable on industrial treatment Use Category Wood Species Preservative Post treatment conditioning (if applicable) Labeling as CSA compliant Inspection 3rd Party quality assurance (if available)

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Overview of CSA O80 Series Originally for industrial products

• Poles, ties, bridge timbers, docks

Rise of residential treated wood market required new standards • Decks, fences, gazebos

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Overview of CSA O80 Series-08 Based on a Use Category System Matches level of treatment to decay/termite risk

• Formalizes some earlier categories. Adds others Derived from USA AWPA standards Compatible with ISO 21887

• Committee secretariat and chair were Canadian Designed to be more accessible to specifiers

• Start at Table 1 to understand use categories • Go to Table 2 to locate products and uses

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Understanding Use Categories CSA O80.1 Table 1* Use categories and associated service conditions

Use Category

Service Conditions

Use Environment

Typical Products

UC1 Interior, above ground, dry

Protected from weather

Interior framing

UC2 Interior, above ground, damp

Protected but can be exposed to moisture

Sillplates

* Available at www.durable-wood.com

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Understanding Use Categories CSA O80.1 Table 1 Use categories and associated service conditions

Use Category

Service Conditions

Use Environment

Typical Products

UC3.1 Exterior above ground, coated

Protected by coating. Free draining

Coated millwork, siding, trim

UC3.2 Exterior above ground uncoated

Exposed to all weather cycles

Footbridge boards, joists, bridge railing

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Use Category

Service Conditions

Use Environment

Typical Products

UC4.1 Exterior ground contact

Exposed to all weather cycles

Fence posts Bridge decks*

UC4.2 Exterior ground contact Critical uses

Exposed to all weather. High decay potential

Guardrail and sign posts. Piles

*Potential for transfer of dirt onto bridge deck

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Use Category

Service Conditions

Use Environment

Typical Products

UC5A Coastal waters including brackish water

Continuous salt water exposure

Piles, bulk-heads and bracing

UC5B+C Not encountered in Canadian Waters

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Ignore Residential Product Groups

Structural and ground

contact needs incising

Shallow penetration OK for above ground, low decay hazard, if cuts are field-treated.

spores

Actively growing fungus

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Determining the Use Category for Products CSA O80.1 Table 2* (alphabetical)

Product End Use Exposure UC Clause

Lumber and timber

Highway construction

Above ground 3.2 9.2.2.2

Lumber and timber

Highway bridge crossties

Above ground 4.1 9.2.2.2

Piles Highway Construction

Ground contact or fresh water

4.2 9.6

Piles Marine Brackish or salt water

5.1 9.8

* Available at www.durable-wood.com

Re-evaluation Decision RVD2011-06 June 22nd 2011 After a re evaluation* of the heavy duty wood preservatives

creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act and Regulations, is granting continued registration of these products for sale and use in Canada.

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Options for Preservative

* Under intensive scrutiny since 1992

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Options for preservative Interior framing SBX (borate) Residential lumber ACQ, CA or MCA Industrial lumber ACQ or CA Shingles CCA* Plywood CCA* Wood foundations CCA* Utility poles CCA* Bridge timbers Penta*, CCA*, Creosote* Railroad ties Creosote, Penta* Piling Creosote* * Per PMRA June 22nd 2011 re-evaluation decision

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Options for preservative New treatment option may become available soon Dual treatment

• Borate pressure/diffusion treatment followed by creosote Designed to prevent decay during seasoning of ties Also prevents decay that enters via checks in service Protects ties against termite attack Extends life of ties by a factor of two Could be ideal for Douglas-fir bridge timbers

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Options for Preservative: Pro’s and Con’s Product Pro’s Con’s Comments ACQ/CA in water

Clean surface +ve perception

More corrosive, Less fixed, wet

CCA in water

Clean surface Good fixation

Does not penetrate D-fir well, wet

Ministries’ process spec.

ACZA in water

Penetrates D-fir More corrosive Streaky blue, wet

Not available in BC yet

Penta in P9 oil

Penetrates D-fir Moves into checks

Oily surface Sensitizer

Creosote Penetrates D-fir moves into checks

Oily surface, Irritant

Cunap in P9 oil

Penetrates D-fir moves into checks

Oily surface Not available in Canada

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Treatment Substitution: Industrial Product Substitute OK Not OK ACQ/CA CA/ACQ always

CCA ACQ or CA lumber utility poles, marine piles

CCA ACZA always

CCA Creosote outdoors public contact, indoors

CCA Penta on land public contact, marine, indoors

Penta Creosote always

Creosote Penta on land marine

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Options for Preservative What are ACQ/CA?

• Copper ethanolamine – used as an algaecide in swimming pools • Q is quat – a disinfectant • A is azole – a fungicide

What is Creosote? • What’s left when all the valuable stuff has been taken out of oil

What is Pentachlorophenol? • Synthetic chlorinated phenol • Dissolved in oil similar to diesel

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Options for Preservative What is CCA?

• Chromium • Copper – from recycled copper wire • Arsenic – from mining waste

CCA withdrawn from residential market as a result of concerns about playground equipment

We need to put risks in perspective 13 years ago I did three risky things in one day

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I handled CCA treated wood at our field site Pressure Treated Wood

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I had a coffee in Walkerton, Ontario Pressure Treated Wood

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A cab driver had a seizure, lost control, the cab mounted the curb and missed me by millimetres. I was nearly killed.

I walked down a sidewalk in Montreal Pressure Treated Wood

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Pressure Treated Wood I looked up the Statistics for the year 2000 Cars killed ~400 pedestrians Tap water killed 7 people in Walkerton

CCA-treated wood killed nobody (again)

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Pre- and post-treatment conditioning Drying

• Ideally air drying to 25% MC • Kiln drying can be too aggressive

Incising • Perforation improves penetration

Pre-cut/pre-frame • As much as possible • Reduce breaches to treated shell l

Fixation • Required for CCA treated wood

Re-drying • May be specified for some uses

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Comments on Wood Species Stability (warp, checking etc.)

• Douglas fir is stable but not very treatable with CCA* • Lodgepole pine is stable but not very treatable • White spruce is less stable and not very treatable

Treatability • Hemlock is treatable but not very stable • Pacific silver fir is very treatable but not as strong

Strength • Douglas fir is very strong but not very treatable with CCA*

*Not an issue with ACZA or creosote

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BC MoFLNRO Process Spec. for Douglas-fir/CCA

• References CSA O80 processing requirements • Use of coastal D-fir only. Interior D-fir is very difficult to treat • Dry to wood moisture content ideal for CCA treatment • Heat treatment to kill any existing fungus infection • Incising density and depth • Pre-cutting and pre-framing • Solution strength and temperature • Minimum vacuum and pressure periods • Fixation • Requires best management practices for aquatic environments • QA Inspection

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BC MoFLNRO Process Spec. for Douglas-fir/CCA

Overall Results to date: 80% ≥ 10mm and 60% ≥ 13mm CSA O80 requires 80% ≥ 13mm

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BC MoFLNRO Process Spec. for Douglas-fir/CCA One order stood out and was excluded from analysis. Order #4 100% <10mm. Later confirmed to be interior Douglas-fir

Note very different scale for penetration

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Best Management Practices for the Use of Treated Wood In Aquatic and Wetland Environments (BMPs) Prepared by Western Wood Preservers Institute (USA)

and Wood Preservation Canada Specific recommendations for each preservative Processes to minimize mobility of preservative

• e.g. CCA fixation Processes to maximize cleanliness of wood surface

• e.g. expansion bath and end of creosote treatment Installation and maintenance guidelines BMP quality assurance inspection procedures

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Quality Assurance All treating plants are certified by the Canadian Wood Preservation

Certification Agency for compliance with Environment Canada’s Technical Recommendations Documents for Design and Operation of A Treating Plant. Environmental and worker health requirements only.

None of the treated wood in lumber yards is certified to CSA standards • Except permanent wood foundation (PWF) lumber and plywood

QA is available from various inspection agencies • No 3rd party oversight

Inspection is only truly valid at treating plant since percent compliance is done by charge (one cylinder full) of treated wood.

For CSA – measure preservative penetration and retention (loading) and/or review plant records

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Quality Assurance Twenty core samples removed per charge

• Cores may be split in half: ½ for penetration and ½ for retention • Penetration: spray with reagent for Cu and Measure • Retention for CCA/ACZA: grind and analyse by X-ray • Retention for creosote: normally done by gauge uptake

For BC FLNRO Process Spec. – Review plant records only Treater may be on a regular inspection program with random visits or Inspector may just be called in to inspect one particular order Potential for third party oversight by Canadian Wood Preservers

Bureau (Available in Ontario. Requested by BC FLNRO)

Sample Inspection Report

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Quality Assurance

Material as specified

Penetration and retention as per

CSA O80


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Quality Assurance

Compliance with MOFLNRO Process Specification


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Quality Assurance

Quality Assurance

Don’t accept “treatment to refusal” Treating plant treatment certificates

are worth the value of the paper Use third party quality assurance

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Care and Handling to Ensure Durability Where possible fabricate prior to treatment Ideally allow to air dry before installation Place uncut ends in ground contact

Field treat all cut ends Cap tops of posts to shed water Apply water repellant if checking is a concern

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Long Term Performance How long does it last? Documented life in FPInnovations field tests

when treated to CSA O80 Standards • CCA treated jack pine roundwood posts >>60 years • CCA treated unincised hem-fir decking >>30 years • CCA treated incised SPF lumber in soil >>25 years • Creosote treated jack pine posts >> 70 years

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Long Term Performance

0

12

3

45

6

7

89

10

0 1 2 3 4 5

Years of Exposure

AWPA

Rat

ing

untreated white spruce untreated western red cedarACQ-D 6.4 kg/m3

Linear (untreated white spruce) Linear (untreated western red cedar)Linear (ACQ-D 6.4 kg/m3)ACQ treated Spruce vs Western red cedar as 2x4

Presentation Review Pressure treatment process Specifying wood for industrial use Overview of CSA O80 Series: Wood Preservation Understanding Use Categories 1 through 5A Products and Use Categories for specific exposures Options for preservative Appropriate and inappropriate preservative substitution Pre- and post-treatment conditioning Comments on species for strength, stability and treatability BCMoFLNRO Process Specification Third party quality assurance Handling of treated wood to maximize durability Long term performance

Any Questions?

www.durable-wood.com