Guide for installation of impregnation plants for timber

IS 2683: Scope - Key Points & Specifications

Scope Summary:

• IS 2683 covers essential requirements for timber preservation plants and associated equipment.
• It excludes mobile plants.
• Emphasis on international coordination and local practices.

Key Specification (Clause 3.6.4):

• Provide a water tank:
  • Minimum height: 6 meters
  • Capacity: at least one week's water requirement
  • Must have necessary pipe connections.

Relevant Units & Definitions (SI Units per IS 2683)

Practical Notes:

• Water tank sizing depends on weekly water demand; calculate volume accordingly.
• Tank height ensures adequate gravity-fed pressure for the plant.
• Compliance with IS 2-1960 rounding rules for measurements and test results.

flowchart TD
    A[Water Tank] --> B{Height >= 6 m}
    A --> C{Capacity >= 1 week's requirement}
    A --> D[Pipe Connections]
    B & C & D --> E[Essential for Timber Preservation Plant]

For detailed design of water tanks or timber treatment processes, refer to IS 401-1967 and relevant pressure vessel codes.

IS 2683: Pressure Treatment Plants – Key Points

1. Types of Pressure Treatment Plants

• Oil-type preservatives (require elevated temperatures)
• Water-soluble preservatives (used at room temperature)
• Equipment adapts for Full Cell, Lowry, and Rueping processes (IS 401-1967).

2. Essential Components (Clause 3.3 & Fig.1)

• Pressure Treating Cylinder: Main vessel for timber treatment.
• Service Tank: Same size as open tank, with steam coils and lid.
• Storage Tanks: For preservative solutions; connected with steam pipes.
• Auxiliary Equipment:
  • Air compressor-cum-vacuum pump
  • Centrifugal pump
  • Pressure and temperature recorders

3. Line Diagram Elements (Fig.1)

4. Specifications Summary

• Service tank must comply with Clause 2.1.3(a) (material, size, steam coil specs).
• Steam coils ensure uniform heating.
• Stop-cocks for controlled drainage and flow management.
• Plant design must allow for different pressure processes and seasoning if required.

Simplified Process Flow (Mermaid Diagram)

flowchart LR
    StorageTank(D) -->|Steam pipes| TreatmentTankA(A)
    StorageTank(D) -->|Steam pipes| TreatmentTankB(B)
    TreatmentTankA -->|Drainage| PitTank(C)
    TreatmentTankB -->|Drainage| PitTank(C)
    CentrifugalPump(E) --> TreatmentTankA
    CentrifugalPump(E) --> TreatmentTankB
    AirCompressor --> TreatmentCylinder

**For detailed dimensions, materials, and operational parameters, refer to IS 2683 clauses 2.

IS 2683 Key Points for Pressure Cylinder Design

1. Design Pressure & Safety Factor

• Working Pressure (P): 1.4 MPa
• Factor of Safety (FOS): 1.9
• Reference Standard: IS 2825-1969 (Code for Unfired Pressure Vessels)

2. Material & Design

• Cylinder material and design must comply with IS 2825-1969.
• Steam heating coils and temperature instruments are not mandatory for Pressure Cylinder (Clause 2.2.1).

3. Size & Volume

• Length: Based on maximum timber length or multiples thereof.
• Diameter: Based on volume of timber per charge.

4. Rueping Cylinder (Auxiliary Cylinder)

• Working Pressure: 550 kPa
• FOS: 1.5
• Capacity: ≥ 75% of treating cylinder capacity
• Connections: To treating cylinder, air compressor, air vent, discharge cocks.
• Alternative: High-pressure centrifugal pump (~700 kPa) may replace Rueping cylinder.

5. Basic Thin Cylinder Thickness Formula (From IS 2825)

[ t = \frac{P \times D}{2 \times \sigma \times \eta - P} ]

Where:

• ( t ) = thickness of cylinder wall
• ( P ) = design pressure (Pa)
• ( D ) = internal diameter (m)
• ( \sigma ) = allowable stress of material (Pa)
• ( \eta ) = joint efficiency (usually 1 for seamless)

Summary Table

flowchart LR
    A[Treating Cylinder] --> B[Pressure Cylinder (1.4 MPa)]
    A --> C[Rue

IS 2683: Design & Material Requirements Summary

1. Material Specifications

• Mixing Tank: Mild steel plates per IS: 2825-1969 or IS: 803-1976.
• Open Tank (Single): Pressed steel or mild steel plates per IS: 803-1976 or IS: 804-1967.
• Heating coils: 25 mm bore steam pipes, protected from direct timber contact.

2. Design Requirements

3. Accessories

• Steam traps, inlet/outlet pipes, valves, cocks.
• Water tank ≥ 6 m height, capacity for 1 week's requirement (Clause 3.6.4).

Key Formula for Tank Volume (Open Tank)

[ V_{tank} = 2 \times V_{timber} ]

Where:

• (V_{tank}) = volume of open tank
• (V_{timber}) = volume of timber per charge

flowchart TB
    A[Timber Charge Volume] -->|x2| B[Open Tank Volume]
    B --> C[Rectangular Tank]
    C --> D[Vertical Angle Irons + Cross Bars]
    C --> E[Heating Coils (25 mm bore)]
    C --> F[Top Cover (0.8 mm GI Sheet)]

This ensures durability, ease of operation, and compliance with IS 2683.

IS 2683: Heating Units and Steam Systems – Key Points & Specifications

Heating Units (Clauses 2.1.1.4 & 2.1.2.2)

• Heating Coil & Steam Pipes:
  • Cylinder equipped with heating coil connected to steam line via external control valve.
  • Steam pipes run at cylinder bottom, protected by perforated steel plate.
  • Live steam connection with holes spaced 45 cm apart for conditioning/cleaning.
• Steam Traps: Installed at ends of steam pipe lines to remove condensate.
• Lagging: Cylinder and exposed steam pipes must be insulated to minimize heat loss.

Pressure Cylinder (Clause 2.2.1)

• Must comply with general cylinder requirements.
• Steam heating coils and temperature instruments are not mandatory.

Condenser and Boiler (Clause 2.2.6)

• Required when conditioning/sterilizing green timber.
• Must meet specifications in Clauses 2.1.5 (Condenser) and 2.1.12 (Boiler).

Typical Formula for Heat Loss Reduction by Lagging:

[ Q = \frac{2 \pi k L (T_{steam} - T_{ambient})}{\ln(r_2/r_1)} ]

• (Q): Heat loss (W)
• (k): Thermal conductivity of lagging (W/m·K)
• (L): Length of pipe (m)
• (r_1), (r_2): Inner and outer radius of lagging (m)
• (T_{steam}), (T_{ambient}): Temperatures (°C)

Summary Table: Steam Pipe Hole Spacing & Protection

flowchart LR
    Steam_Line --> Control_Valve
    Control_Valve --> Heating_Coil
    Heating_Coil --> Cylinder
    Cylinder --> Lagging
    Steam_Pipes --> Perforated_Steel_Plate
    Steam_Pipes --> Steam_Traps
    Steam_Pipes --> Lagging

**Ensure all installations comply with IS

IS 2683: Storage Tanks Key Points

1. Number & Capacity

• Minimum two tanks: one for creosote, one for fuel oil.
• Capacity: to hold 4 to 6 months stock of preservatives (decided by supplier & purchaser).

2. Material & Design

• Conform to:
  • IS 2825-1969 (Code for unfired pressure vessels), or
  • IS 803-1976 (Code of practice for vertical mild steel cylindrical welded oil storage tanks).

3. Accessories

• Level gauge
• Manhole with cover
• Ladders (inside & outside if necessary)

4. Connections

• Bottom connections for:
  • Filling
  • Connection to mixing/service tank

Additional Notes on Service Tanks (Clause 2.1.3)

• Material/design: same IS codes as above.
• Capacity: equal to treating cylinder.
• Accessories include:
  • Gauge (accuracy ±10 litres)
  • Manhole, drain valve, steam coils, thermometer (up to 120℃)
  • Antifloat device for bogie stability

Typical Formula for Tank Volume (Vertical Cylindrical Tank):

[ V = \pi \times r^2 \times h ]

Where:

• (V) = volume (m³)
• (r) = radius (m)
• (h) = height (m)

flowchart TD
    A[Storage Tanks] --> B[Material & Design]
    B --> IS2825[IS 2825-1969]
    B --> IS803[IS 803-1976]
    A --> C[Capacity]
    C --> D[4 to 6 months stock]
    A --> E[Accessories]
    E --> F[Level gauge]
    E --> G[Manhole with cover]
    E --> H[Ladders]
    A --> I[Connections]
    I --> J[Bottom filling]
    I --> K[Mixing/Service tank]

Summary: IS 2683 mandates at least two tanks, designed per IS 2825/803, sized for 4-6 months' stock, equipped with level gauges, manholes, ladders, and proper connections.

IS 2683 Key Points on Pumps and Piping

1. Centrifugal Pumps (Clause 2.1.6.1)

• Used for transferring preservatives between tanks and cylinders.
• Capacity: Must fill/empty the treating cylinder in ~10 minutes.
• Multiple pumps can be used for required capacity.

2. Hydraulic Pressure Pump (Clause 2.1.6.3)

• Must generate 1.4 MPa pressure within 15 minutes.
• Maintain pressure continuously for 4-5 hours.
• Used when cylinder is fully loaded and filled with preservative.

3. Rueping Cylinder (Clause 2.1.2)

• Design pressure: 550 kPa with safety factor 1.5.
• Capacity: ≥ 75% of treating cylinder capacity.
• Alternative: High-pressure centrifugal pump (~700 kPa) can replace Rueping cylinder.

4. Pumps and Related Equipment (Clause 2.2.5)

• Must comply with clauses 2.1.6 to 2.1.11.

Summary Table

flowchart LR
    A[Service Tank] -->|Preservative| B[Centrifugal Pump]
    B --> C[Treating Cylinder]
    C --> D[Storage Tank]
    C --> E[Measuring Tank]
    C -->|Pressure 1.4 MPa| F[Hydraulic Pressure Pump]
    F --> C
    G[Rueping Cylinder] --> C

Note: Refer IS 2825 for Rueping cylinder material and design details.

IS 2683: Key Specifications for Condenser and Vacuum Systems

Condenser (Clause 2.1.5)

• Material: Mild steel plates.
• Design Standards: IS 2825-1969 (Unfired pressure vessels) or IS 803-1976 (Vertical mild steel welded tanks).
• Capacity: Adequate for system requirements.
• Accessories:
  • Catch pot vessel for condensate discharge.
  • Conical receiver for water and preservative oil separation.
  • Positioned between vacuum pump line and goose neck.
  • Interceptor to protect vacuum pump from vapour condensation.

Vacuum System Components

• Vacuum-pressure gauge: Range up to 76 cm Hg and 2.0 MPa.
• Goose neck:
  • Height: 12 m.
  • Bore diameter: 50 to 70 mm.
  • Purpose: Prevent overflow of heating medium during vacuum boiling.

Air Compressor-cum-Vacuum Pump (Clause 2.1.6.2)

• Compressor mode: Creates 500 kPa pressure in 10 minutes.
• Vacuum mode: Creates 60 cm Hg vacuum in 10-15 minutes.

Typical Dimension Summary

Simplified Flow Diagram of Vacuum System

flowchart LR
    Cylinder -->|Goose Neck| GooseNeck
    GooseNeck -->|To Condenser| Condenser
    Condenser -->|Condensate to Catch Pot| CatchPot
    CatchPot -->|Separated Water & Oil| Receiver
    Condenser -->|To Vacuum Pump| VacuumPump

This ensures effective condensation and vacuum maintenance per IS 2683.

IS 2683: Bogies and Rail-Track Arrangements Key Points

Bogies (Clause 2.1.7)

• Number: Minimum 2 sets; one for loading, one for treatment; plus 1-2 spare bogies.
• Wheels: Each bogie has 4 wheels.
• Bearings: Preferably low friction (ball/roller) bearings with waterproof grease (water-borne plants) or special grease (creosote plants).
• Structure: Steel stanchions to hold timber; coupling arrangements mandatory.
• Length: Determined by timber size to fill the treatment cylinder.

Rail-Track (Clause 2.1.1.3)

• Gauge: Narrow or metre gauge depending on cylinder size.
• Length: Runs entire cylinder length inside.
• Guard Rails: Required to prevent bogie derailment.

Track Scale (Clause 2.1.9)

• Capacity: Accurate to 1 kg.
• Rails: Same gauge as trolley track.
• Length: Long enough for 1-2 coupled trolleys.
• Placement: Preferably one at each cylinder end.

Summary Table

flowchart LR
    A[Loading Bogie] --> B[Treatment Cylinder]
    B --> C[Unloading Bogie]
    B -. Guard Rails .-> B
    B --> D[Track Scale (both ends)]
    A -. Coupling .-> C

This arrangement ensures smooth timber handling during preservative treatment as per IS 2683.

IS 2683 - Winch and Loading Equipment: Key Points

• Winch (Clause 2.1.8):

  • Used for loading/unloading timber charges in cylinders.
  • Must have suitable capacity accessories based on load.
  • Can be electrically or manually operated.

• Related Equipment (Clause 2.2.5):

  • Pumps, bogies, winch, track scale, water tanks, and motors must comply with Clauses 2.1.6 to 2.1.11.

• Track Scale (Clause 2.1.9):

  • Platform weighing machine with accuracy up to 1 kg.
  • Rails must match trolley gauge.
  • Length to accommodate 1-2 coupled trolleys.
  • Preferably two machines, one at each cylinder end.

• Portable Cranes (Clause 3.6.2):

  • Required for large tanks treating big timber like poles/sleepers.

Typical Winch Capacity Calculation (General Engineering Practice):

[ \text{Winch Capacity (kN)} = \frac{\text{Load Weight (kN)} \times \text{Safety Factor}}{\text{Efficiency}} ]

• Safety Factor: 1.5 to 2.0
• Efficiency: 0.8 to 0.9 (depending on winch type)

Summary Table:

flowchart LR
    A[Timber Loading] --> B[Winch or Manual Arrangement]
    B --> C{Capacity Check}
    C -->|Adequate| D[Load Timber into Cylinder]
    C -->|Inadequate| E[Upgrade Winch or Use Crane]
    D --> F[Track Scale Weighing]
    F --> G[Confirm Load Accuracy]

This ensures safe, efficient timber handling per IS 2683 requirements.

IS 2683: Plants for Water Soluble Preservatives - Key Points

Types of Plants (Clause 2.2)

• Pressure Plants: Used for water soluble preservatives at room temperature.

  • Subdivided based on pressure processes:
    • Full Cell Process
    • Lowry Process
    • Rueping Process (See IS 401-1967+)
  • Equipment modifications depend on the chosen process.
  • Auxiliary equipment should allow switching between these processes.
  • Additional equipment may be needed for timber conditioning (e.g., steaming, Boulton process).

• Open Tank Plants (Clause 3)

  • Simpler, non-pressure treatment.
  • Suitable for water soluble preservatives without pressure application.

Important Specifications

• Plants must handle room temperature water soluble preservatives.
• Must allow pressure treatments for Full Cell, Lowry, or Rueping processes.
• Provision for timber seasoning/conditioning equipment if required.

Reference: IS 401-1967+

• Details on pressure processes (Full Cell, Lowry, Rueping).
• Conditioning methods like steaming or Boulton process.

Typical Process Flow (Simplified)

flowchart LR
    A[Timber Loading] --> B[Conditioning (Optional)]
    B --> C[Preservative Solution Preparation]
    C --> D[Pressure Treatment Chamber]
    D --> E[Retention & Drying]
    E --> F[Unloading & Storage]

This summarizes the core layout for water soluble preservative plants using pressure treatment.

For detailed dimensions, pressures, and retention times, refer to IS 401-1967 and relevant process-specific tables therein.

IS 2683 - Open Tank Treatment Plants: Key Specifications & Formulas

1. Open Tank Design (Clause 3.1)

• Material: Pressed steel or mild steel plates.
• Design Standard: As per IS 803-1976 or IS 804-1967.
• Shape: Rectangular; length based on maximum timber length.
• Volume: Tank volume ≈ 2 × volume of timber per charge.
• Reinforcement: Vertical angle irons welded inside long sides; cross bars to prevent timber floating.

2. Heating & Accessories

• Heating Coils: Steam pipes ≥ 25 mm bore, placed 5 cm above tank bottom.
• Heating Time: Raise preservative + timber temp to 95°C in ~1 hour.
• Top Cover: 0.8 mm thick galvanized iron sheet, sectional for easy removal.
• Accessories: Steam trap, inlet/outlet piping, valves, stop-cocks.

3. Service Tank (Clause 3.3)

• Same size as open tank.
• Equipped with steam coils and lid.
• Complies with Clause 2.1.3(a) requirements.

4. Volume Calculation Formula

[ V_{tank} = 2 \times V_{timber} ]

Where:

• (V_{tank}) = volume of preservative tank (m³)
• (V_{timber}) = volume of timber charge (m³)

5. Typical Line Diagram Components (Fig. 1 & 2)

• A & B: Treatment tanks with steam coils
• C: Drainage pit below ground
• D: Storage tank
• E: Centrifugal pump
• Multiple stop-cocks (X, Y, Z, M, N, P, Q) for flow control and drainage

flowchart LR
    D(Storage Tank) -->|Preservative| A(Treatment Tank A)
    D -->|Preservative| B(Treatment Tank B)
    A & B -->|Drainage| C(Drainage Pit)
    E(Centrifugal Pump) --> A & B
    subgraph Stop-cocks
        X & Y & Z & M & N & P & Q
    end

Summary: Design open tanks as per IS

Key Specifications & Formulas for Tank Design (IS 2683)

1. Service Tank

• Material & Design: As per IS 2825-1969 (Unfired Pressure Vessels) or IS 803-1976 (Vertical Mild Steel Cylindrical Welded Oil Storage Tanks).
• Capacity: Equal to treating cylinder capacity.
• Accessories:
  • Gauge (±10 L accuracy) or separate gauging tank.
  • Manhole with cover.
  • Drain valve.
  • Steam coils with control valves & steam trap.
  • Thermometer (up to 120°C).
  • Antifloat device for bogie stability.

2. Mixing Tank

• Material & Design: Mild steel plates per IS 2825 or IS 803.
• Capacity: ≥ ¼ of service tank capacity.
• Shape: Preferably cylindrical.

3. Storage Tank

• Number: Minimum two (for creosote & fuel oil).
• Material & Design: IS 2825 or IS 803.
• Capacity: 4-6 months stock capacity (as agreed).
• Accessories: Level gauge, manhole, ladders.
• Connections: Bottom connections to mixing/service tanks and filling.

4. Open Tank (Single)

• Material & Design: Pressed or mild steel plates per IS 803 or IS 804.
• Shape: Rectangular; volume ≈ 2× timber volume per charge.
• Accessories: Steam trap, piping, valves.
• Top Cover: 0.8 mm GI sheet in 3-4 removable sections.
• Heating Coils: 25 mm steam pipes, 5 cm above bottom, raise temp to 95°C in 1 hour.

Important Design Considerations

• Volume of Open Tank:

  [ V_{\text{tank}} = 2 \times V_{\text{timber charge}} ]

• Steam Coil Heating:

  • Use sufficient coils to uniformly heat preservative + timber to 95°C in ~1 hour.
  • Coils should be protected to prevent timber damage.

Summary Table: Tank Capacities & Accessories

| Tank Type | Material Standard | Capacity | Shape | Key Accessories | |---------------|-------------------|-------------------------|

IS 2683: Twin-Tank Systems for Wood Preservative Treatment

Key Specifications & Setup (Clauses 3.2, 3.2.1)

• Two identical open tanks placed side-by-side.
• Connected by a wide pipe with stop cock at 2/3 height for hot preservative transfer.
• Each tank has steam coils at bottom for heating.
• Extra-wide drainage pipe with stop cock at 2/3 height for quick drainage to underground pit.
• Service tank same size as open tanks, with steam coils and lid (Clause 3.3).
• Continuous operation: Hot preservative displaced from one tank to the other, cold preservative fills the first tank simultaneously, enabling efficient heating/cooling cycles.

Treatment Procedure (Clause 3.2.1)

1. Load timber in Tank A, fill with hot preservative, heat via steam coils.
2. Open stop cock at 2/3 height to transfer hot preservative to Tank B.
3. Cold preservative from storage tank fills Tank A simultaneously.
4. Drain preservative from Tank A to drainage pit while cooling timber.
5. Repeat cycle alternating tanks.

Design Notes

• Mixing tank capacity ≥ 1/4 service tank capacity (Clause 2.2.4).
• Tanks made of mild steel plates per IS 2825 / IS 803.
• Cylindrical preferred for mixing tanks.

Diagram: Twin-Tank System Flow

flowchart LR
    A[Treatment Tank A] -- Hot Preservative --> B[Treatment Tank B]
    B -- Hot Preservative --> A
    Storage[Storage Tank] -- Cold Preservative --> A
    Storage -- Cold Preservative --> B
    A -- Drainage --> Pit[Drainage Pit]
    B -- Drainage --> Pit
    A -- Steam Coils Heating --> A
    B -- Steam Coils Heating --> B

Summary of Stop Cock Locations:

This twin-tank system optimizes heating, cooling, and preservative

IS 2683 - Other Accessories & Instrumentation Key Points

Clause 3.6: Other Accessories

• Water Tank: Minimum height 6 m, capacity for at least one week's water requirement.
• Must have necessary pipe connections.

Clause 1.4: Instrumentation Specifications

• Safety valve adjustable to 1.4 MPa pressure.
• Stop-cock and piping connections for hydraulic pump.
• Air compressor-cum-vacuum pump included.
• Thermometer capable of reading up to 150°C.

Clause 2.2.5: Equipment Compliance

• Pumps, bogies, winch, track scale, water storage tank, and motors must comply with Clauses 2.1.6 to 2.1.11.

Summary Table: Key Accessories

Notes:

• Water tank sizing depends on daily consumption × 7 days.
• Safety valve pressure ensures system protection.
• Equipment must follow relevant IS codes for pressure vessels and tanks (e.g., IS for mild steel tanks).

flowchart LR
    WaterTank[Water Tank ≥ 6 m height]
    SafetyValve[Safety Valve @ 1.4 MPa]
    StopCock[Stop-cock & Piping]
    AirPump[Air Compressor-cum-Vacuum Pump]
    Thermometer[Thermometer up to 150°C]

    WaterTank -->|Pipe Connections| StopCock
    StopCock --> SafetyValve
    SafetyValve --> AirPump
    AirPump --> Thermometer

This ensures safe, reliable operation of hydraulic and water systems per IS 2683.