Code of practice for preservation of plywood and other panel products

IS 12120: Scope & Key Specifications Summary

The code IS 12120 covers preservative treatment of plywood and related wood products to enhance durability under various exposure conditions.

Key Points from Clause 8.2.1:

• Net retention of preservatives is evaluated by:
  • Service tank readings, or
  • Weight difference before and after treatment.
• Manufacturers must maintain an absorption log book and provide a certificate for net absorption (kg/m³).
• Table 1: Composition & concentration of different preservatives.
• Table 2: Absorption rates and treatment processes for preservatives.
• For water-soluble preservatives, concentration is checked with calibrated hydrometers.

Exposure Conditions (Clause 1.0):

General Notes:

• Preservative retention depends on type of preservative, wood species, and exposure.
• Treatment processes and absorption values are standardized in the tables for quality control.

Example: Net Retention Calculation

[ \text{Net Retention (kg/m}^3) = \frac{\text{Weight after treatment} - \text{Weight before treatment}}{\text{Volume of wood (m}^3)} ]

If you need detailed tables or specific preservative compositions, please specify!

IS 12120: Key Specifications on Preservative Treatment of Wood Panels

1. Recommended Preservative Treatment (Clause 8.2, Table 2)

• Service Conditions: Different wood products (green veneer, particle board, plywood in seawater/cooling towers).
• Preservatives & Minimum Absorption (kg/m³): Refer to Table 1 for chemical compositions and absorption values.
• Examples of Absorption Values:
  • Green veneer: 160 kg/m³ (1(a), 1(b), 1(c))
  • Particle board: 130 kg/m³ (1(a), 1(b))
  • Plywood in seawater: 80 kg/m³ (1(a), 1(b), 1(c))

2. Treatment Methods

• Full cell to refusal for refractory species.
• Diffusion or Lowry process for green timber (stack under cover for 2 weeks).
• Brush treatment: 6% solution, 2 coats (second after first dries).

3. General Remarks

• Materials are mostly sapwood or non-durable woods.
• Avoid coal tar/oily preservatives if further painting is required.

Summary Table (Simplified)

Refer IS 12120 Table 1 & 2 for detailed preservative codes and chemical compositions.

flowchart TD
    A[Wood Product Type] --> B{Service Condition}
    B -->|Green Veneer| C[Preservative 1(a),1(b),1(c)]
    B -->|Particle Board| D[Preservative 1(a),1(b)]
    B -->|Plywood in Sea Water| E[Preservative 1(a),1(b),1(c)]
    C --> F[Absorption 160 kg/m³]
    D --> G[Absorption 130 kg/m³]
    E --> H

IS 12120 - Terminology & Key Specifications Summary

• Clause 2.1: Definitions refer to IS 707-1976 (Timber Technology Glossary) and IS 401-1982 (Timber Preservation Code).

• Preservative Types (Clause 3.1):

  Type	Description	Chemicals Included
  1	Oil Type	Coal tar creosote ± petroleum oils (marine borers protection)
  2	Organic Solvent Type	Copper/zinc naphthenates, copper acetate, pentachlorophenol, DDT, dieldrin
  3	Water Soluble Non-fixed Type	Zinc chloride, boric acid, borax, sodium fluoride, sodium pentachlorophenate
  4	Water Soluble Fixed Type	Copper-chrome arsenic, chromated zinc chloride, copper-chrome-boric

• Preservative Retention (Clause 8.2.1):

  • Net retention = Weight before treatment - Weight after treatment (kg/m³)
  • Absorption log book required for certification.
  • Concentration of preservatives can be measured by calibrated hydrometers.

• Tables (referenced):

  • Table 1: Composition and concentration of preservatives for different timber types.
  • Table 2: Absorption rates and treatment processes.

Key Formula for Net Retention of Preservatives:

[ \text{Net Retention (kg/m}^3) = \frac{\text{Weight after treatment} - \text{Weight before treatment}}{\text{Volume of timber (m}^3)} ]

Practical Notes:

• Use IS 401-1982 for detailed preservative descriptions.
• For plywood and boards, refer to specific exposure conditions for treatment concentration (e.g., open, contact with water/land).
• Rounding off numerical values follows the revised rules in IS 12120.

flowchart LR
    A[Timber] --> B[Treatment with Preservative]
    B --> C{Type of Preservative}
    C -->|Type 1| D[Oil Type]
    C -->|Type 2| E[Organic Solvent Type]
    C -->|Type 3|

IS 12120 - Choice of Treatment (Clause 4.1)

Key Points:

• Choice of Treatment depends on:

  • Timber species
  • Sapwood content
  • End use of the treated product (Clause 4.1.1)

• Preparation of Material (Clause 1.2):

  • Proper seasoning and surface preparation before treatment to ensure effective preservative penetration.

• Recommended Practices (Clause 4.1.3):

  • Preservative type
  • Treatment process
  • Amount of absorption (retention)
  • Penetration requirements

Important Tables (from IS 12120):

Typical Formula for Retention (kg/m³):

[ \text{Retention} = \frac{\text{Amount of preservative absorbed (kg)}}{\text{Volume of timber (m}^3)} ]

Summary:

• Select preservative & process based on species, sapwood %, and use.
• Ensure minimum retention & penetration as per Tables 1 & 2.
• Follow preparation guidelines for optimal treatment.

flowchart TD
    A[Timber Species & Sapwood] --> B{End Use}
    B --> C[Choose Preservative Type]
    B --> D[Select Treatment Process]
    C --> E[Check Retention & Penetration]
    D --> E
    E --> F[Prepare Material]
    F --> G[Treatment Execution]

For detailed values, refer to Tables 1 & 2 of IS 12120.

IS 12120: Types of Treatment – Key Points

1. Choice of Treatment (Clause 4.1)

• Selection depends on type of material, intended use, and preservative.
• Consider moisture content before treatment (Clause 4.2.4) to adjust soaking/diffusion time.

2. Preparation of Material (Clause 1.2)

• Material must be prepared (cleaned, cut) to ensure uniform preservative penetration.

3. Treatment Methods (Clause 5.2)

• Common methods include:
  • Soaking
  • Pressure treatment
  • Diffusion
• Duration depends on moisture content and preservative type.

4. Preservative Absorption & Penetration (Clause 4.1.3)

• Refer to Tables 1 & 2 for:
  • Recommended preservative types.
  • Minimum absorption (kg/m³).
  • Minimum penetration depth (mm).

(Values indicative; check IS 12120 Tables 1 & 2 for exact data)

flowchart TD
    A[Material Preparation] --> B[Moisture Content Check]
    B --> C{Select Treatment Method}
    C -->|Soaking| D[Soaking Duration]
    C -->|Pressure| E[Pressure & Time]
    C -->|Diffusion| F[Diffusion Period]
    D & E & F --> G[Preservative Absorption & Penetration]
    G --> H[Quality Check & Compliance]

Summary:
Moisture content controls treatment duration. Use Tables 1 & 2 for preservative specs. Choose treatment based on material and application.

IS 12120: Conditioning After Treatment – Key Points

1. Preparation Before Treatment (Clauses 1.2, 4.2.1, 4.2.4)

• Material must be clean, free of oil/dirt, and moisture content ≤ 16%.
• For treatments requiring cutting/boring (Clause 5.1), finish these before treatment to avoid untreated surfaces.
• Moisture content affects soaking/diffusion time (Clause 4.2.4).

2. Net Retention & Absorption (Clause 8.2.1)

• Net retention of preservatives = difference in weight before and after treatment (kg/m³).
• Maintain an absorption log book and provide a certificate of net absorption.
• Use service tank readings or weight measurements to evaluate absorption.
• For water-soluble preservatives, use calibrated hydrometers to measure concentration.

3. Reference Tables (from Clause 8.2.1)

• Table 1: Composition & concentration of preservatives.
• Table 2: Absorption rates and treatment processes.
• Includes data for green debarked logs and prophylactic brushing/spraying concentrations.

Summary Table Example (simplified):

flowchart TD
    A[Material Preparation] --> B{Moisture ≤ 16%?}
    B -- Yes --> C[Finish machining if needed]
    B -- No --> D[Dry material]
    C --> E[Preservative Treatment]
    D --> E
    E --> F[Measure Weight Before & After]
    F --> G[Calculate Net Retention]
    G --> H[Record in Absorption Log Book]

This ensures proper conditioning after treatment per IS 12120 for durable, well-preserved wood.

IS 12120: Workmanship and Finish - Key Points

Moisture Content (Clause 6.2)

• After treatment (veneers/chips), dry material to ≤ 10% moisture content for optimal gluing.

Workmanship and Finish (Clause 7)

• Finished products must be clean, free from dirt and stains, except uniform preservative color.
• Surfaces should be smooth and free of defects affecting durability or appearance.

Exposure Categories (Clause 1.0)

Preparation for Treatment (Clause 4.2.1)

• Material must be clean, oil/dirt-free, moisture content ≤ 16% before treatment.
• Prefer finishing (cutting, boring) before treatment to avoid untreated areas.

Summary Table: Moisture Content for Treatment & Gluing

This ensures durability, adhesion quality, and surface finish consistent with IS 12120 standards.

flowchart TD
    A[Raw Material] --> B[Clean & Dry (≤16% Moisture)]
    B --> C[Treatment (Preservatives)]
    C --> D[Drying (≤10% Moisture)]
    D --> E[Cutting/Boring (Preferably Before Treatment)]
    E --> F[Finished Product: Clean,

IS 12120 Sampling and Testing - Key Points

Sampling (Clause 8.1)

• Samples must be taken from batches as per:
  • IS 303:1975 (Sampling of timber)
  • IS 1659:1979 (Sampling of plywood)
  • IS 2380 (Parts 1 to 21):1974 (Sampling of various materials)

Testing (Clause 8.2)

• Net absorption of preservatives is determined by chemical analysis per:
  • IS 2753 (Part 1):1964
  • IS 2753 (Part 2):1968

Preservative Absorption (Tables 1 & 2)

• Tables detail types of preservatives and minimum recommended absorption levels (kg/m³ or % by weight).

Summary Table (Example)

Additional Notes:

• Finished products must be clean and free from dirt/stains (Clause 7.1).
• Sampling/testing labs and regional offices are listed for reference and quality assurance.

flowchart TD
    A[Batch of Material] --> B[Sampling as per IS 303, IS 1659, IS 2380]
    B --> C[Chemical Analysis per IS 2753 Parts 1 & 2]
    C --> D[Determine Net Preservative Absorption]
    D --> E[Compare with Recommended Values (Tables 1 & 2)]
    E --> F{Accept/Reject Batch}

For detailed absorption values and test procedures, refer to IS 12120 Tables 1 & 2 and IS 2753 Parts 1 & 2.

IS 12120: Preservatives and Their Compositions (Clause 8.2, Table 1 & 2)

Key Preservatives and Their Compositions (Table 1)

Net Absorption & Treatment (Clause 8.2.1 & Table 2)

• Net retention is measured by weight difference or service tank readings.
• Manufacturers maintain an absorption log and certify net absorption in kg/m³.
• Hydrometers calibrated for concentration measurement are used for water-soluble preservatives.
• Chemical analysis per IS 2753 (Part 1 & 2) is mandatory.

Summary:

• Choose preservative based on wood type & treatment method (green debarked logs or prophylactic brushing).
• Use Table 1 for composition & concentration.
• Use Table 2 for absorption rates and treatment processes.
• Maintain records for absorption and certify per IS standards.

flowchart TD
    A[Wood Material] --> B{Choose Preservative Type}
    B --> C[Coal Tar Based]
    B --> D[Oil Soluble Chemicals]
    B --> E[Water Soluble Dispersible]
    B --> F[Water Soluble Fixed

IS 12120: Penetration and Retention of Preservatives

Key Points & Formulas

• Net retention (R) of preservative is calculated by:

  [ R = \frac{\text{Weight after treatment} - \text{Weight before treatment}}{\text{Volume of timber}} \quad (kg/m^3) ]

• Retention can also be checked via service tank readings or absorption logs maintained by the manufacturer.

• Penetration is assessed by extracting samples at least 15 cm from edges or from borings/cross-sections (Clause 8.2.2).

• Chemical analysis for net absorption uses methods from IS 2753 (Part 1 & 2).

Tables Summary (Refer IS 12120 Tables 1 & 2)

Note: Concentrations vary for green debarked logs and prophylactic treatments.

Preservative Concentration Measurement

• Use calibrated hydrometers for solution concentration.

• Maintain absorption log books for quality control.

Diagram: Penetration Assessment Sampling

flowchart LR
    A[Treated Timber] --> B{Sample Location}
    B --> C[≥ 15 cm from edges]
    B --> D[Borings]
    B --> E[Cross-cut surfaces]
    C --> F[Chemical Analysis]
    D --> F
    E --> F

References:

• IS 12120 Clauses 4.1.3, 8.2, 8.2.1, 8.2.2
• IS 2753 (Parts 1 & 2) for chemical analysis
• IS 401-1982 Appendix D for penetration methods

IS 12120: Handling and Storage - Key Specifications

1. Service Conditions & Treatment (Clause 8.2, Table 2)

2. Preservative Treatment Guidelines (Clause 4.1.3, 8.2.1)

• Preservative types & compositions: See Table 1 (includes copper, arsenic, chromium compounds, creosote, etc.)
• Treatment methods: Diffusion, Lowry process, full cell to

IS 12120 - Safety & Environmental Considerations for Wood Preservatives

Key Preservative Types (Clause 8.2, Table 1)

Recommended Minimum Absorptions (kg/m³) for Various Conditions (Clause 8.2, Table 2)

General Safety & Environmental Notes

• Use non-oily preservatives if painting is planned to ensure adhesion.
• For green timber, use diffusion or Lowry process;

IS 12120 - Documentation and Certification for Preservative Treatment

Key Points from Clause 8.2.1 and Related Tables:

• Net retention of preservatives is evaluated from:

  • Service tank readings
  • Weight difference before and after treatment

• Manufacturer's Responsibility:

  • Maintain an absorption log book
  • Furnish a certificate stating net absorption in kg/m³

• Preservative Composition & Concentration:

  • Refer Table 1 for preservative types and concentrations for different wood conditions (green debarked logs, brushing, spraying).
  • Refer Table 2 for absorption rates and treatment processes.

• Concentration Measurement:

  • Use calibrated hydrometers for water-soluble preservatives.

Typical Documentation Includes:

Example Formula for Net Absorption (kg/m³):

[ \text{Net Absorption} = \frac{\text{Weight after treatment} - \text{Weight before treatment}}{\text{Volume of wood (m}^3\text{)}} ]

Summary:

• Maintain detailed logs and certificates as per IS 12120.
• Use prescribed tables for preservative compositions and concentrations.
• Verify preservative concentration using calibrated hydrometers.
• Follow IS test methods for quality assurance.

flowchart TD
    A[Wood Before Treatment] --> B[Preservative Treatment]
    B --> C[Wood After Treatment]
    C --> D[Calculate Net Absorption]
    D --> E[Record in Log Book]
    E --> F[Issue Certificate]
    F --> G[Quality Assurance Testing]

For detailed tables (composition, absorption), refer to IS 12120 Table 1 & 2.

IS 12120: Amendments and Updates Summary

IS 12120 (1987) covers preservation of plywood and panel products. Key amendments include:

• Amendment No. 1 (March 2001): Updates to preservation methods and materials to improve durability.
• Amendment No. 2 (August 2002): Changes in Table 1 (Page 6, SI No. 2) specifying preservation chemical concentrations or application procedures.

Important Notes:

• No explicit formulas are provided in amendments.
• Table 1 (as amended) lists recommended preservatives and their concentrations for different panel types.
• Preservation methods focus on chemical treatment, storage conditions, and application techniques.

Typical Preservation Specifications (from IS 12120):

Summary Diagram: Preservation Process

flowchart LR
    A[Raw Panel Products] --> B[Chemical Treatment]
    B --> C[Drying]
    C --> D[Storage in Dry Place]
    D --> E[Usage or Further Processing]

Always refer to the latest amendment for exact chemical types and concentrations.

IS 12120: Key Appendices - Preservative Treatment of Plywood & Wood Panels

1. Preservative Chemicals & Minimum Absorptions (Table 1)

• Specifies composition & concentration of preservatives.
• Minimum absorption in kg/m³ depends on wood type & service condition.
• Examples:
  • Green veneer: ~160 kg/m³ absorption.
  • Chips for particle board: ~160 kg/m³.
  • Plywood in contact with seawater: 130 kg/m³.
• Use hydrometers for solution concentration measurement.

2. Recommended Treatment Processes & Absorption (Table 2)

• Defines treatment methods based on service exposure:
  • Open exposure with wetting/drying.
  • Contact with land or water (fresh/marine).
  • Indoor humid conditions.
• Treatment types: full cell, diffusion, Lowry process, brush (6% solution, 2 coats).
• Absorption varies by preservative & exposure; e.g., brush treatment requires 6% solution with two coats.

3. Preservative Retention Evaluation (Clause 8.2.1)

• Net retention = (weight before - weight after treatment) / volume.
• Maintain absorption log book & certificate.
• Use service tank readings or weight difference.

4. General Remarks

• Non-durable or sapwood requires full treatment.
• Avoid coal tar/oily preservatives if painting is planned.
• Treatment tailored per wood durability & exposure.

Summary Table (Simplified):

flowchart TD
    A[Wood Panel] --> B{Service Condition}
    B -->|Open wet/dry| C[Full Cell Treatment]
    B -->|Contact with land/water| D[Diffusion or Lowry Process