Methods for estimation of preservatives in treated timber and in treating solutions, Part 2: Determination of copper (in copper organic preservative salt) and pentachlorophenol

IS 2753 Part 2: Scope & Key Formulas for Estimation of Preservatives

Scope (Clause 1.1):

• Quantitative estimation of:
  • Copper in copper organic preservative salt solutions and treated timber.
  • Pentachlorophenol in pentachlorophenol oil solutions and treated timber.

Key Formula (Clause 5.327) for Pentachlorophenol Estimation

[ D = (A - B) \times 5.327 ]

Where:

• ( A = (\text{ml silver nitrate for sample}) - (\text{ml ammonium thiocyanate for sample}) \times (\text{ammonium thiocyanate factor}) )
• ( B = (\text{ml silver nitrate for blank}) - (\text{ml ammonium thiocyanate for blank}) \times (\text{ammonium thiocyanate factor}) )
• ( D ) = Volume of sample in cm³

Notes:

• The standard ensures quality control under BIS supervision.
• Results should be rounded as per IS 2:1960.
• Applies to timber treated with copper organic salts and pentachlorophenol oils.

Summary Table:

This standard complements IS 401:1982 (Timber Preservation Code).
For detailed procedures and factors, refer to the full IS 2753 Part 2 document.

IS 2753 Part 2: Quality of Reagents & Key Formulas

1. Quality of Reagents (Clause 2)

• Use pure chemicals and distilled water as per IS 1070:1977 for all tests.
• Ensures accuracy in chemical analysis of preservative oils and treated wood.

2. Preparation & Estimation of Copper (Clause 3.3.1)

• Evaporate filtered treating solution to destroy organics.
• Digest with 2 ml H2SO4 + 3 ml HNO3, heat till dissolved.
• Transfer, heat till SO3 fumes appear, cool, add water.
• Neutralize with ammonium hydroxide to precipitate, dissolve with sulfuric acid.
• Boil down, dilute to 125 ml.
• Add 10 ml 20% potassium iodide + 5 ml 20% sodium thiocyanate.
• Titrate with sodium thiosulphate using starch indicator.

3. Key Formula for Pentachlorophenol Content (Clause 5.327)

[ \text{Kilogram pentachlorophenol/m}^3 = \frac{(A - B) \times 5.327}{D} ]

Where:

4. Preparation of 20% Potassium Iodide Solution (Clause 3.2.6)

• Dissolve 20 g KI in water and dilute to 100 ml.

flowchart TD
    A[Filtered Treating Solution] --> B[Evaporate solvent]
    B --> C[Add H2SO4 + HNO3, heat]
    C --> D[Transfer & heat till SO3 fumes]
    D --> E[Neutralize with NH4OH

IS 2753 Part 2 specifies chemical methods for quantitative estimation of copper in copper organic preservative salts and treated timber.

Key Points & Specifications:

• Scope:

  • Estimation of copper in copper organic preservative salt solutions and in timber treated with these salts.
  • Also covers pentachlorophenol but focus here is copper.

• Reagents Quality:

  • Use pure chemicals and distilled water as per IS 1070:1977.

• General Methodology:

  • Sample preparation involves extracting copper from timber or solution.
  • Copper content is typically determined by complexometric titration (e.g., EDTA method) or colorimetric methods using suitable reagents.

Typical Formula for Copper Estimation by EDTA Titration:

[ \text{Copper content (mg/L)} = \frac{V \times N \times 63.5 \times 1000}{\text{Volume of sample (mL)}} ]

Where:

• ( V ) = volume of EDTA used (mL)
• ( N ) = normality of EDTA
• 63.5 = atomic weight of copper

Summary Table for Copper Estimation:

flowchart LR
    A[Sample Preparation] --> B[Extraction of Copper]
    B --> C[Titration with EDTA]
    C --> D[Calculate Copper Content]

For detailed stepwise procedures and reagent preparation, refer to IS 2753 Part 2 (1991).

IS 2753 Part 2: Sample Preparation & Concentration Requirements

Key Steps & Specifications

1. Sample Mass (Clause 3.1)

• Sample solution should contain ~0.02 g copper for accurate titration.

2. Treating Solution Preparation (Clause 3.3.1)

• Evaporate filtered solution to dryness.
• Destroy organics by strong heating.
• Add 2 ml H₂SO₄ + 3 ml HNO₃, heat until dissolved.
• Transfer to 300 ml flask, heat until SO₃ fumes appear.
• Cool, wash sides with 5 ml water, repeat heating.
• Add 20 ml water, boil 1 min, cool.
• Neutralize with ammonium hydroxide until precipitate forms.
• Redissolve precipitate with sulfuric acid dropwise.
• Boil down to 30 ml, cool <20°C, dilute to 125 ml.
• Add 10 ml 20% KI + 5 ml 20% sodium thiocyanate.
• Titrate with sodium thiosulphate; add starch indicator near endpoint.

3. Lime Nitrate Mixture Treatment (Clause 4.3.1)

• Weigh 10 g lime nitrate in crucible.
• Add 0.5-1 g pentachlorophenol evenly.
• Cover with 20 g lime nitrate, tap gently.
• Heat at 850–900°C for 20 min; extend if carbon remains.
• Cool, transfer to 400 ml beaker.
• Add 70 ml water, scrub crucible, wash with 2% HNO₃ if needed.
• Final volume ≤ 100 ml.
• Neutralize lime with concentrated HNO₃ until acidic to Congo red (blue → red).

4. Acid Specifications (Clause 4.2.4)

• Use concentrated nitric acid, volume ratio 1:42, chloride-free.

Summary Table

IS 2753 Part 2: Key Reagents and Solutions

• Potassium Iodide Solution (20%)

  • Dissolve 20 g KI in water and dilute to 100 ml.
  • Used as a stabilizer or reagent in titrations.

• Standard Silver Nitrate Solution (0.1 N)

  • Dissolve 16.989 g AgNO₃ in water and make up to 1 litre.
  • Used for titrations involving halides.

• Sodium Thiosulphate Solution

  • Dissolve 2.4821 g Na₂S₂O₃·5H₂O in water and dilute to 1 litre.
  • Commonly used as a titrant in iodometry.

• Ammonium Thiocyanate Solution

  • Preparation details typically involve dissolving a specified amount in water to a set volume (refer to clause 4.2.7 for exact quantity).

Summary Table

These solutions are essential for chemical analysis and titrations in cement testing as per IS 2753.

IS 2753 Part 2: Estimation Procedures for Treated Timber & Treating Solutions

Key Points:

• Basis of Calculation:
  Estimation is done on volume basis of timber (Clause 4.3.2.1), as moisture content varies.

• Scope (Clause 1.1):

  • Copper in copper organic preservative salt solutions and treated timber.
  • Pentachlorophenol in pentachlorophenol solutions (in oil) and treated timber.

• Formula Correction (Clause 3.3.1.1):
  Substitute 0.0635 for 0.635 in the relevant calculation formula.

General Formula for Estimation (Example for Pentachlorophenol):

[ % \text{Pentachlorophenol} = \frac{C \times V \times F}{W} ]

Where:

• ( C ) = Concentration from titration/analysis
• ( V ) = Volume of solution used
• ( F ) = Factor (corrected as per clause 3.3.1.1)
• ( W ) = Weight or volume of timber sample

Reference:

• IS 401:1982 for detailed preservative treatment methods.
• Rounding off as per IS 2:1960.

Summary Table:

flowchart LR
    A[Treated Timber Sample] --> B[Sample Preparation]
    B --> C[Chemical Analysis]
    C --> D[Calculate Concentration]
    D --> E[Apply Correction Factor (0.0635)]
    E --> F[Estimate % Preservative on Volume Basis]

For precise formulas and titration methods, refer directly to IS 2753 Part 2:1991 text.

Quantitative Estimation of Pentachlorophenol (PCP) in Solution and Treated Timber
(IS 2753 Part 2)

Key Formula for PCP Content (% by mass)

[ \text{PCP %} = \frac{(A - B) \times 0.532}{C} ]

Where:

• A = [(ml , \text{AgNO}_3 \text{ for sample}) - (ml , \text{NH}_4\text{SCN for sample}) \times \text{NH}_4\text{SCN factor}]
• B = [(ml , \text{AgNO}_3 \text{ for blank}) - (ml , \text{NH}_4\text{SCN for blank}) \times \text{NH}_4\text{SCN factor}]
• C = Mass of sample taken (g)
• 0.532 = Conversion factor based on molecular weight and titration stoichiometry

Notes:

• Silver nitrate (AgNO₃) and ammonium thiocyanate (NH₄SCN) volumes are titration readings.
• The NH₄SCN factor is a correction factor from standardization.
• Sample mass must be accurately weighed for precise results.

Summary Table

This method ensures accurate quantification of pentachlorophenol in oil solutions and timber for quality control and compliance with preservation standards.

IS 2753 Part 2: Scope & Sample Limitations - Key Formulas & Specifications

1. Scope

• Covers estimation of copper (in copper organic preservative salts) and pentachlorophenol in treated timber and treating solutions.
• Applies to preservative detection per IS 401:1982 (timber preservation code).
• Ensures compliance with BIS quality and inspection systems.

2. Sample Volume Calculation (Clause 5.327)

[ D = (A - B) \times 5.327 ]

Where:

• ( A = (\text{ml silver nitrate for sample}) - (\text{ml ammonium thiocyanate for sample}) \times \text{ammonium thiocyanate factor} )
• ( B = (\text{ml silver nitrate for blank}) - (\text{ml ammonium thiocyanate for blank}) \times \text{ammonium thiocyanate factor} )
• ( D ) = Volume of sample in cm³
• The factor 5.327 converts volume basis to kg pentachlorophenol per m³ wood.

3. Sample Dimensions

• Increment boring: 2 cm long, 0.475 cm diameter
• Volume = ( \pi \times (0.475/2)^2 \times 2 = 0.3546 , cm^3 )

4. Titration Procedure Highlights (Clause 4.2.6)

• Add 15 ml of 0.1 N silver nitrate, boil to coagulate silver chloride.
• Filter, wash till no turbidity with ammonium thiocyanate.
• Final volume after washing: 200-250 ml
• Back titrate excess silver nitrate with ammonium thiocyanate indicator.

Summary Table: Sample Volume Calculation

Here are the key reagents, preparation methods, and specifications from IS 2753 Part 2:

Reagents & Preparation

• Potassium Iodide Solution (20%)
  Dissolve 20 g KI in water and dilute to 100 ml.

• Standard Silver Nitrate Solution (0.1 N)
  Dissolve 16.989 g AgNO₃ in water and dilute to 1 litre.

• Ferric Ammonium Sulphate Indicator
  Dissolve 10 g ferric ammonium sulphate in 10 ml concentrated HNO₃, dilute to 100 ml with water.

Treating Solution Preparation (Clause 3.3.1)

1. Evaporate known mass of filtered solution in porcelain dish till organic matter is destroyed.
2. Add 2 ml H₂SO₄ + 3 ml HNO₃, gently heat till dissolved.
3. Transfer to 300 ml flask, heat till SO₃ fumes appear, solution clears.
4. Wash, boil, cool, neutralize with ammonium hydroxide until precipitate forms.
5. Add H₂SO₄ dropwise till precipitate dissolves.
6. Boil down to 30 ml, cool below 20°C, dilute to 125 ml.
7. Add 10 ml 20% KI + 5 ml 20% sodium thiocyanate, mix.
8. Titrate with sodium thiosulphate; add 2 ml starch before endpoint (blue color disappears).

Summary Table

This procedure ensures precise chemical preparation for titrations and analysis per IS 2753 Part 2.

IS 2753 Part 2: Estimation Procedures for Treated Timber & Solutions

Key Points:

• Basis of Calculation: Volume basis (Clause 4.3.2.1), to avoid errors due to moisture content variability.
• Scope (Clause 1.1): Quantitative estimation of:
  • Copper in copper organic preservative salts (both solution & treated timber).
  • Pentachlorophenol in oil solutions and treated timber.
• Corrections: Use factor 0.0635 instead of 0.635 in relevant formulae (Clause 3.3.1.1).

Typical Formula for Pentachlorophenol % in Treated Timber:

[ % \text{Pentachlorophenol} = \frac{C \times V \times F}{W} \times 100 ]

Where:

• (C) = concentration of pentachlorophenol in test solution (mg/ml)
• (V) = volume of test solution (ml)
• (F) = dilution factor
• (W) = weight or volume of timber sample (adjusted for moisture)

Estimation Steps:

1. Extract preservative from treated timber sample.
2. Analyze concentration via chemical methods.
3. Calculate preservative % using above formulae on volume basis.

Reference:

• For detailed chemical procedures and tables, refer to IS 2753 Part 2:1991.
• Follow IS 2:1960 for rounding off numerical results.

flowchart LR
    A[Treated Timber Sample] --> B[Extraction of Preservative]
    B --> C[Chemical Analysis]
    C --> D[Calculate % Preservative]
    D --> E[Report Results (Volume Basis)]

This approach ensures accurate quantification of copper and pentachlorophenol in treated timber and solutions as per IS 2753 Part 2.

Key Formulas & Specifications from IS 2753 Part 2 for Calculations:

1. Pentachlorophenol Content (% by mass):
   [ \text{Pentachlorophenol %} = (A - B) \times 0.5327 \times C ] Where:

• (A = (\text{ml silver nitrate for sample}) - (\text{ml ammonium thiocyanate for sample}) \times \text{ammonium thiocyanate factor})
• (B = (\text{ml silver nitrate for blank}) - (\text{ml ammonium thiocyanate for blank}) \times \text{ammonium thiocyanate factor})
• (C = \text{mass of sample in grams})

2. Pentachlorophenol Content (kg per m³ of wood):
   [ \text{Content (kg/m}^3) = (A - B) \times 5.327 \div D ] Where:

• (A, B) as above
• (D = \text{volume of sample in cm}^3)

3. Copper Content (kg per m³ of wood):
   [ \text{Copper (kg/m}^3) = \frac{M \times V \times 0.635}{M_1 \times 100} ] Where:

• (V = \text{volume in ml of sodium thiosulphate consumed})
• (M = \text{mass of sample in grams})
• (M_1 = \text{mass of 1 m}^3 \text{ of wood in kg})

Notes:

• Calculations are volume-based due to moisture content variability.
• Use accurate titration readings for silver nitrate, ammonium thiocyanate, and sodium thiosulphate.
• Ensure sample mass and volume are precisely measured.

flowchart TD
    A[Sample Preparation] --> B[Titration with Silver Nitrate]
    B --> C[Subtract Blank Titration]
    C --> D[Calculate (A-B)]
    D --> E{Choose Calculation}
    E -->|Pentachlorophenol \%| F[Multiply by 0.5327 and Sample

IS 2753 Part 2: Reporting of Results - Key Formulas and Specifications

Key Formula (Clause 5.327) for Pentachlorophenol Content:

[ \text{Pentachlorophenol (kg/m}^3) = \frac{(A - B) \times 5.327}{D} ]

Where:

• (A = (\text{ml silver nitrate for sample}) - (\text{ml ammonium thiocyanate for sample}) \times \text{ammonium thiocyanate factor})
• (B = (\text{ml silver nitrate for blank}) - (\text{ml ammonium thiocyanate for blank}) \times \text{ammonium thiocyanate factor})
• (D = \text{Volume of sample in cm}^3)

Reporting Guidelines:

• Final values must be rounded as per IS 2:1960 "Rules for rounding off numerical values".
• Results should clearly state units (kg/m³ for pentachlorophenol).
• Report both raw titration values and calculated preservative content.
• Include details of sample volume and titration reagents used.

Additional Notes:

• BIS Standard Mark ensures compliance with IS 2753 under BIS supervision.
• Use the formula for copper and pentachlorophenol estimation in treating solutions and treated timber as per clauses 3.3.1 and 5.327.
• Follow sample preparation and titration steps carefully for accurate results.

flowchart TD
    A[Sample Preparation] --> B[Titration with Silver Nitrate]
    B --> C[Calculate A and B values]
    C --> D[Apply formula: (A-B)*5.327/D]
    D --> E[Report pentachlorophenol content (kg/m³)]
    E --> F[Rounding off as per IS 2:1960]

This concise approach ensures clarity and accuracy in reporting preservative content per IS 2753 Part 2.

Safety and Handling Precautions (IS 2753 Part 2 Highlights)

Key Chemicals & Handling:

• Nitric Acid (Concentrated) [Clause 3.2.4] and Sulphuric Acid (Concentrated) [Clause 3.2.5] require careful handling under a fume hood due to their corrosive and toxic fumes.
• Use personal protective equipment (PPE): gloves, goggles, lab coat, and work in a well-ventilated area.
• Avoid direct inhalation and skin contact.

Chemical Treatment Procedure [Clause 3.3.1]:

• Evaporate and destroy organic matter under a hood.
• Use a porcelain dish and electric hot plate with burner heating.
• Follow sequential acid digestion with sulfuric and nitric acids.
• Neutralize cautiously with ammonium hydroxide to avoid violent reactions.
• Final titration with sodium thiosulphate using starch as an indicator.

Important Formula for Pentachlorophenol Content (Clause 5.327)

[ D = (A - B) \times 5.327 ]

Where:

Summary Table: Handling Precautions

IS 2753 Part 2: References and Related Standards Summary

• Key Related Standard:

  • IS 401:1982 – Code of Practice for Preservation of Timber (3rd Revision)
    Covers preservative types, treatment methods; IS 2753 Part 2 details detection/estimation of copper (in copper organic salts) and pentachlorophenol in treated timber and solutions.

• Important Formula (Clause 5.327):
  Calculation of pentachlorophenol (kg/m³ wood volume):
  [ D = (A - B) \times 5.327 ] Where:
  [ A = (ml , \text{AgNO}_3 \text{ for sample}) - (ml , \text{NH}_4\text{SCN for sample}) \times \text{NH}_4\text{SCN factor} ] [ B = (ml , \text{AgNO}_3 \text{ for blank}) - (ml , \text{NH}_4\text{SCN for blank}) \times \text{NH}_4\text{SCN factor} ] [ D = \text{Volume of sample (cm}^3) ]

• Standards Governance:

  • BIS Act 1986 governs the use of Standard Mark, ensuring quality through inspection and testing.
  • Products with Standard Mark comply with BIS supervised quality control.

• Amendments & Revisions:

  • Indian Standards are periodically reviewed and amended.
  • Users should confirm possession of latest edition/amendments.

• Rounding Off:

  • Follow IS 2:1960 for rounding numerical results.

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