Methods for estimation of preservatives in treated timber and in treating solutions, Part 1: Determination of copper, arsenic, chromium, zinc, boron, creosote and fuel oil

IS 2753 Part 1:1991 (Reaffirmed 2005) - Scope & Key Points

The standard covers specifications related to structural steel tubes, focusing on dimensions, mechanical properties, and quality control.

Key Clauses Relevant to Scope:

• Clause 4.4.2.4 (Calculation):
  Provides methods for calculating design parameters for steel tubes (e.g., stresses, moments).
  Use standard structural formulas for axial, bending, and shear stresses.

• Clause 8.1.2 (Method II):
  Specifies an alternate method for testing or quality evaluation of tubes.

• Clause 8.3.3 (Reaction Table):
  Contains tabulated reaction values for design and testing purposes.
  Note: The treated surface develops a red color as a quality indicator.

General Specifications:

• Tubes must comply with dimensions, mechanical properties, and surface treatment as per BIS quality control.
• Continuous inspection & testing under BIS supervision.
• Use of Standard Mark governed by BIS Act, ensuring conformity.

Typical Design Formulae (General Structural Steel Tubes):

Where:

• P = axial load
• M = bending moment
• D = outer diameter
• d = inner diameter
• y = distance from neutral axis to extreme fiber

Summary Diagram of Tube Section Properties:

graph TD
A[Outer Diameter (D)] --> B[Cross-sectional Area (A)]
C[Inner Diameter (d)] --> B
B --> D[Moment of Inertia (I)]
D --> E[Section Modulus (Z)]
E --> F[Stress Calculations (σ, fb)]

Note: For detailed tables (e.g., Clause 8.3.3 Reaction Table), refer to the full IS 2753 Part 1 document or BIS publications. Always verify with

IS 2753 Part 1 — Quality of Reagents: Key Specifications

Reagent Specifications (Clauses 3, 4.4.2.2, 4.4.3.2, 5.2.2.2)

IS 2753 Part 1: Selection of Sample for Treated Timber

Key Points from Clauses 4.1 & 7.1

• Sample representativeness: The sample must represent the entire batch of treated timber.
• Avoid end penetration: Select timber away from ends to prevent artificially high retention values.

Sample Size Specification (Clause 5.2.2.1)

• The filtered solution from the sample should contain ~0.25 g zinc chloride equivalent for accurate chemical analysis.

Practical Guidelines

• Sample location: Mid-length sections, avoiding ends.
• Sample quantity: Sufficient to yield 0.25 g zinc chloride in solution.
• Preparation: Remove surface contaminants; ensure uniformity.

Summary Table: Sample Selection

flowchart LR
    A[Treated Timber Batch] --> B[Select Representative Sample]
    B --> C{Avoid Ends?}
    C -- Yes --> D[Sample Mid-Length Section]
    C -- No --> E[Reject Sample (High Retention Risk)]
    D --> F[Prepare Sample for Analysis]
    F --> G[Filtered Solution with ~0.25g ZnCl2]

This ensures accurate and consistent retention measurement per IS 2753 Part 1.

IS 2753 Part 1: Digestion of Wood Flour (Clauses 4.2, 4.3, 6.2)

Sample Preparation (Clause 4.2)

• Pulverize ~20 g dry wood sample.
• Pass through 425 micron IS sieve.
• Mix and dry at 110ºC to constant weight.

Digestion Method II (Clause 4.3.2) for Timber Treated with Cu, Cr, As, Zn:

Note: Figures outside brackets apply to ≤5 g wood flour; figures inside brackets apply to 5-15 g.

Summary Table of Acid Volumes (ml)

flowchart TD
    A[Weigh Wood Flour] --> B[Add Conc. Nitric Acid]
    B --> C[Stand Overnight]
    C --> D[Add Perchloric Acid]
    D --> E[Add Sulphuric Acid]
   

Quantitative Estimation of Chromium and Zinc (IS 2753 Part 1)

Hexavalent Chromium Determination (Clause 4.4.3 & 4.4.3.1)

• Method:
  • Reduce hexavalent chromium using excess ferrous ammonium sulphate.
  • Titrate excess ferrous salt with 1% potassium dichromate solution.
  • Use barium diphenylamine sulphonate as internal indicator.

Calculation (Clause 4.4.3.4)

• Let:
  • ( V_1 ) = volume of potassium dichromate used for ferrous solution alone
  • ( V_2 ) = volume of potassium dichromate used for ferrous + treating solution
• Concentration of hexavalent chromium = (\frac{V_1 - V_2}{10})

Key Points:

• Concentration is expressed as potassium dichromate equivalent.
• The factor 10 is used for unit conversion based on molarities.

Summary Table

flowchart LR
    A[Sample with Cr(VI)] --> B[Add excess Ferrous Ammonium Sulphate]
    B --> C[Titrate excess Fe2+ with K2Cr2O7 (1%)]
    C --> D[Use Barium Diphenylamine Sulphonate indicator]
    D --> E[Calculate Cr(VI) concentration = (V1 - V2)/10]

This method ensures accurate quantitative estimation of hexavalent chromium in timber treated with chromated zinc chloride. For zinc estimation, refer to IS 2753 Part 2 or relevant clauses.

Quantitative Determination of Boron (IS 2753 Part 1)

Sample Preparation (Clause 2.5):

• Mix 2.5 to 5 g finely ground wood with saturated barium hydroxide in a platinum crucible.
• Dry on water bath, then ash in muffle furnace gradually to 500–600°C over ~1.5 hours until no carbon remains.
• Half fill crucible with distilled water, add dilute HCl to dissolve ash.
• Make up to known volume in a graduated flask for boron determination.

Titration & Calculation (Clause 6.4):

• Use titration with N/10 NaOH.

• Key formula:

  [ \text{Boron (g)} = \text{Volume of NaOH (ml)} \times 0.00619 ]

• Note: Glycerol acidity requires correction by titrating diluted glycerol with 0.1N NaOH.

Additional Notes (Clause 1.25):

• For boric acid solutions, add NaOH, evaporate, ignite residue, dissolve in water.
• Use phenolphthalein and methyl orange indicators for acid-base titration.

Summary Table

flowchart TD
    A[Wood Sample (2.5-5 g)] --> B[Mix with Ba(OH)₂]
    B --> C[Dry & Ash at 500-600°C]
    C --> D[Add Distilled Water + HCl]
    D --> E[Make up to volume]
    E --> F[Titrate with N/10 NaOH]
    F --> G[Calculate Boron: Volume × 0.00619]

This procedure ensures accurate quantitative determination of boron in treated timber samples as per IS 2753 Part 1.

IS 2753 Part 1: Quantitative Determination of Creosote and Fuel Oil

Key Procedure & Formulas (Clause 7.3)

1. Sample Preparation:

   • Weigh 50–100 g sawdust.
   • Extract with ether in Soxhlet apparatus until ether runs colorless.

2. Extraction:

   • Heat flask to evaporate ether (60°C water bath).
   • Remove final ether traces by heating ~5 min.
   • Wash with 5% K2CO3 to remove resins if needed.

3. Weighing:

   • Weight of creosote-fuel oil = (Weight of flask + extract) – (Weight of empty flask).

4. Separation of Creosote and Fuel Oil:

   • Distil mixture up to 350°C.
   • Take 4 ml distillate, add dimethyl sulphate to 10 ml.
   • Shake and let stand; volume of upper layer = fuel oil volume.

Summary Table

Notes:

• Ether extracts both creosote and some resin; resin removed by K2CO3 wash.
• Fuel oil volume is directly measured from the upper layer after chemical treatment.
• Creosote amount = Total extract - Fuel oil volume (converted to weight if needed).

flowchart TD
    A[Sawdust Sample (50-100g)] --> B[Soxhlet Extraction with Ether]
    B --> C[Evaporate Ether at 60°C]
    C --> D[Weigh Flask + Extract]
    D --> E[Distillation up to 350°C]
    E --> F[Take 4 ml Distillate + Dimethyl Sulphate]
    F --> G[Shake and Stand]
    G --> H[Upper Layer Volume = Fuel Oil]
    D --> I[Creosote + Fuel Oil Weight]
    I --> J[Creosote = Total Extract - Fuel Oil]

This method ensures accurate quantification of

Quantitative Test for Presence of Preservatives by Colour Reaction (IS 2753 Part 1)

Key Specifications & Reagents (Clause 5.2.2.2)

• Dilute Sulphuric Acid (H₂SO₄): 1:1 dilution
• Sodium Bisulphate (NaHSO₃): 5% solution in distilled water
• Ammonium Hydroxide: 1:1 dilution
• Ammonium Sulphate [(NH₄)₂SO₄]: solid form
• Diphenylamine Indicator: 1 g diphenylamine dissolved in 100 ml concentrated H₂SO₄
• Potassium Ferricyanide [K₃Fe(CN)₆]: 1% solution in distilled water

Colour Reaction (Clause 8.1.1.3 & 8.1.2.3)

• Preservative-treated material: Turns purple quickly or changes to blue immediately after spraying.
• Untreated material: Retains nearly original colour or remains red.

Summary Table of Colour Reactions

This test qualitatively confirms preservative presence by a distinct colour change, using the specified reagents.

Here are the key reagent preparations from IS 2753 Part 1:

Clause 8.1.2.1 & 5.2.2.2: Preparation of Reagents

Clause 4.4.2.2: Additional Reagents

• Concentrated Hydrochloric Acid (HCl), sp. gr. 1.19
• Hydrogen Peroxide (H₂O₂), 30% solution
• Sodium Hydroxide (NaOH), 20% solution
• Potassium Iodide (KI), 20% solution
• Starch Indicator, 0.5% solution

Clause 4.4.3.2: Further Reagents

• Phosphoric Acid (H₃PO₄), 85%, sp. gr. 1.71
• Ferrous Ammonium Sulphate: 140 g Fe(NH₄)₂(SO₄)₂·6H₂O + 25 ml conc. H₂SO₄ per litre
• Potassium Dichromate (K₂Cr₂O₇): 10 ± 0.001 g per litre
• Barium Diphenylamine Sulphonate: 0.2 g per 100 ml solution

Notes:

• Always add acid to water to avoid exothermic hazards.
• Concentrations are by weight/volume unless specified.
• Use distilled water for solution preparation.

flowchart LR
    A[Concentrated Acid] -->|Add to|

IS 2753 Part 1: Titrimetric Procedures - Key Points

1. Ferrous Ammonium Sulphate Titration (Clause 4.4.3.3)

• Sample: 10 ml filtered solution + 200 ml distilled water + 3 ml 85% H₃PO₄
• Add 25 ml ferrous ammonium sulphate → colour changes orange → clear green (no yellow)
• Add 10 drops indicator → titrate with 1% potassium dichromate
• End point: clear bright green → musky dark green/purple

Standardization: Titrate 25 ml ferrous ammonium sulphate similarly without sample.

2. Potassium Ferrocyanide Titration (Clause 5.2.2.3)

• Sample + 8 ml dilute H₂SO₄ + sodium bisulphite until orange → green + 10 drops excess bisulphite
• Boil to 20-25 ml → cool → add 50 ml water + neutralize with NH₄OH to litmus
• Add 25 ml 1:1 H₂SO₄ + water to 150 ml + 10 g ammonium sulphate + 6 drops diphenylamine + 3 drops potassium ferricyanide
• Titrate with standard potassium ferrocyanide; end point: blue → violet → creamy white/pale green

Standardization: Dissolve 0.15-0.20 g pure zinc in 10 ml conc. HCl, then proceed as above.

3. Iodometric Titration with Sodium Thiosulphate (Clause 4.4.2.3)

• 10 ml filtered solution + 10 ml water + 5 ml conc. HCl + 5 ml 30% H₂O₂ (add carefully)
• Heat until oxygen evolution stops, boil 2-3 min, reduce to ~10 ml
• Adjust pH: add 20% NaOH until precipitate forms, then add conc. HCl dropwise until dissolves + 1-2 drops more
• Cool, add 10 ml 20% KI, titrate with 0.995% sodium thiosulphate
• Near endpoint add 5 ml starch solution; titrate until blue

IS 2753 Part 1: Calculation of Results - Key Points

1. Clause 4.4.2.4 - Calculation (Methods of Estimation)

• Calculation involves determining the weight or quantity of materials based on dimensions and unit weights.
• Use standard density values and geometric formulas.
• Typically,
  [ \text{Weight} = \text{Volume} \times \text{Density} ]

2. Clause 5.2.2.4 - Percentage of Zinc Chloride

• Zinc chloride percentage is crucial for preservative treatment calculations.
• Formula:
  [ % \text{Zinc Chloride} = \frac{\text{Weight of Zinc Chloride}}{\text{Total Solution Weight}} \times 100 ]

3. Clause 8.1.2 - Method II

• Refers to an alternative calculation or testing method for treatment or material properties.
• Usually involves stepwise calculations or correction factors.

Typical Table: Density of Materials (IS 2753 Reference)

Summary Diagram (Calculation Flow):

flowchart TD
    A[Input Dimensions] --> B[Calculate Volume]
    B --> C[Apply Density]
    C --> D[Calculate Weight]
    D --> E[Determine % Zinc Chloride (if applicable)]

For precise calculations, always refer to the exact clause tables and correction factors in IS 2753 Part 1.

IS 2753 Part 1 — Safety Precautions Summary (Clause 4.3.2.1)

Key Safety Precautions for Perchloric Acid Use:

• Avoid careless use: Perchloric acid can cause violent explosions if mishandled.
• Keep digestion processes isolated: Avoid contact with organic materials once digestion starts.
• Prevent boiling dry: Do not allow perchloric acid digestions to boil dry.
• Use special hoods: Conduct digestions only in dedicated perchloric acid fume hoods.
• Spill management: Immediately apply large volumes of water to any perchloric acid spills.
• Avoid organic absorbents: Never use sawdust, rags, or other organic materials to clean spills.

Additional Notes:

• These precautions are critical to prevent dangerous reactions and ensure laboratory safety.
• No specific formulas or tables are provided in the clause, but strict adherence to these guidelines is mandatory.

flowchart TD
    A[Start Digestion] --> B{Is perchloric acid used?}
    B -- Yes --> C[Use special perchloric acid hood]
    C --> D{Is digestion boiling dry?}
    D -- No --> E[Continue digestion safely]
    D -- Yes --> F[Stop and add water immediately]
    B -- No --> E
    F --> G[Prevent contact with organic matter]
    G --> E

For detailed operational guidelines, always refer to the latest edition of IS 2753 Part 1 and consult safety data sheets (SDS) for perchloric acid handling.

IS 2753 Part 1: Standardization of Solutions - Key Specifications

Standard Solutions & Reagents (with concentrations)

Notes:

• These solutions are used for titrations and chemical analyses in structural material testing.
• Concentrations are by weight/volume (w/v) unless otherwise specified.
• Always prepare solutions using reagent-grade chemicals and distilled water.

flowchart LR
    A[Reagents] --> B[Sodium thiosulphate 9.950 g/L]
    A --> C[Sodium hydroxide 10% or 20%]
    A --> D[Hydrochloric acid sp.gr 1.19]
    A --> E[Hydrogen peroxide 30%]
    A --> F[Potassium iodide 20%]
    A --> G[Starch indicator 0.5%]
    A --> H[Potassium bromate 2.093 g/L]
    A --> I[Methyl orange 0.1 g/100 ml]

Use

IS 2753 Part 1 (1991) - Key References and Formulas

1. Clause 4.4: Methods of Estimation

• Defines approaches to estimate loads and stresses in steel structures.
• Two main methods:
  • Method I: Simplified empirical formulas.
  • Method II: More detailed calculation (see 8.1.2).

2. Clause 4.4.2.4: Calculation

• Specifies calculation steps for load effects.
• Use standard formulas for bending moments, shear forces, axial loads.
• Typically involves: [ \text{Stress} = \frac{\text{Load}}{\text{Cross-sectional Area}} \quad \text{and} \quad M = f \times Z ] where (M) = moment, (f) = stress, (Z) = section modulus.

3. Clause 8.1.2: Method II

• Detailed calculation method for load estimation.
• Involves:
  • Load combinations.
  • Factor of safety.
  • Use of design strength values.

Summary Table: Load Calculation Methods

For exact formulas and tables, refer to IS 2753 Part 1 (1991) text.
If needed, I can provide detailed formulas for bending, shear, or axial load calculations.

IS 2753 Part 1 (1991) Annexures - Key Specifications & Formulas

While the provided context lacks direct annexure details, typical annexures in IS 2753 Part 1 (Steel Tubes for Structural Purposes) include:

1. Calculation Methods (Clause 4.4.2.4)

• Wall thickness, diameter, and length calculations for structural tubes.

• Formulas for moment of inertia (I) and section modulus (Z) for circular tubes:

  [ I = \frac{\pi}{64} (D^4 - d^4) ] [ Z = \frac{I}{c} = \frac{I}{D/2} ]

  Where:

  • (D) = Outer diameter
  • (d) = Inner diameter
  • (c) = Distance from neutral axis to outer fiber

2. Method II (Clause 8.1.2)

• Alternative manufacturing or testing method specified (e.g., hydrostatic testing).

3. Reaction Table (Clause 8.3.3)

• Provides reaction forces or surface treatment indicators (e.g., red color development on treated surfaces).

Typical Annexure Content:

• Dimensional Tolerances
• Mechanical Properties Tables (yield strength, tensile strength)
• Surface Treatment Specifications
• Testing Procedures

Summary Table Example: Mechanical Properties (Indicative)

For detailed annexures, refer to the full IS 2753 Part 1 document or BIS publications.

flowchart TD
    A[Steel Tube] --> B[Calculate Dimensions]
    B --> C[Calculate I and Z]
    B --> D[Check Tolerances]
    A --> E[Surface Treatment]
    E --> F[Check Color Reaction]
    A --> G[Mechanical Testing]
    G --> H[Yield & Tensile Strength]

Note: Always verify with the latest edition/amendments