Laminated veneer lumber - Specification

IS 14616: Scope & Key Specifications for Laminated Veneer Lumber (LVL)

Scope Summary (Clause 9.1 & Intro)

• LVL is a reconstituted ligno-cellulosic product made by laminating veneers.
• Used as a substitute for solid wood in load-bearing members like beams, posts, stringers, and structural framework.
• Eco-friendly alternative to natural wood, overcoming defects like knots, warping, and growth stresses.
• Suitable for structural applications requiring high anisotropic strength along grain.

Key Mechanical Properties (from Table 1, Clause 8.2.3)

Testing Standards

• Strength tests as per IS 1708 (Parts 6,8,9,11,12,15).
• Sampling and conformity per IS 7638.

Summary Diagram: LVL Properties Overview

graph LR
A[LVL Properties] --> B(Modulus of Rupture: 50 N/mm²)
A --> C(Modulus of Elasticity: 7,500 N/mm²)
A --> D(Comp. Strength Parallel: 35 N/mm²)
A --> E(Comp. Strength Perp. Parallel Laminae: 35 N/mm²)
A --> F(Comp. Strength Perp. Perp. Laminae: 50 N/mm²)
A --> G(Horizontal Shear Parallel: 6 N/mm²)
A --> H(Horizontal Shear Perp: 8 N/mm

IS 14616 Key References & Specifications Summary

1. Strength Test Requirements (Clause 8.2.3 & Table 1)

2. Testing Standards (IS 1708 Parts)

• Static bending strength: IS 1708 (Part 6)
• Compressive strength parallel to grain: IS 1708 (Part 8)
• Compressive strength perpendicular to grain: IS 1708 (Part 9)
• Shear strength parallel to grain: IS 1708 (Part 11)
• Tensile strength parallel to grain: IS 1708 (Part 12)
• Nail and screw holding power: IS 1708 (Part 15)

3. Additional References (Annex A)

• IS 401: Timber preservation
• IS 707: Timber terminology
• IS 1734: Plywood density & moisture content
• IS 2380 (Part 17): Swelling in water test for wood boards

This concise data helps verify LVL properties per IS 14616 and guides test methods referencing IS 1708 series.
For detailed test procedures, refer to the respective IS parts.

flowchart LR
    A[LVL Sample] --> B{Tests per IS 1708}
    B --> C[Modulus of Rupture]

IS 14616 - Definitions & Key Specifications for LVL

Definitions

• Refer to IS 707 for timber-related terminology.
• LVL (Laminated Veneer Lumber) properties and test methods align with IS 1708 parts and other referenced IS standards (see Annex A).

Key Mechanical Properties (Table 1, Clause 8.2.3)

Testing Standards (IS 1708 Parts)

• Bending strength: Part 6
• Compressive strength parallel/perpendicular: Parts 8 & 9
• Shear strength: Part 11
• Tensile strength: Part 12
• Nail & screw holding: Part 15

Summary Diagram: LVL Property Testing Flow

flowchart LR
    A[LVL Specimens] --> B{Tests per IS 1708}
    B --> C[Modulus of Rupture (Part 6)]
    B --> D[Modulus of Elasticity]
    B --> E[Compressive Strength Parallel (Part 8)]
    B --> F[Compressive Strength Perpendicular (Part 9)]
    B --> G[Shear Strength (Part 11)]
    B --> H[Tensile Strength (Part 12)]
    B --> I[Nail & Screw Holding Power (Part 15)]
    C & D & E & F & G & H & I --> J[Check against Table 1 requirements]

IS 14616: Key Material Properties & Specifications for LVL

Additional Specifications:

• Moisture content: 5% to 15% (IS 1734 Part 1)
• Testing methods: IS 1708 Parts 6, 8, 9, 11, 12, 15
• Swelling test: IS 2380 Part 17

Testing Protocol:

• Six specimens tested for each property
• Average values must meet above requirements

This ensures LVL's structural reliability and durability per IS 14616 standards.

IS 14616: Manufacture of Laminated Veneer Lumber (LVL) — Key Specifications

Moisture Content (Clause 8.2.1)

• Average moisture content of 3 test specimens: 5% to 15% (per IS 1734 Part 1).

Strength Requirements (Clause 8.2.3, Table 1)

Dimensional Tolerances (Clause 6.2)

• Dressing & finishing margin:
  • Width & thickness: ≤ 3 mm
  • Length: ≤ 12 mm

Permissible Defects (Clause 7)

• Jointing gaps: ≤ 3 mm wide, staggered between plies
• Slope of grain (face layers): ≤ 1 in 10
• Tight knots: max 3 per m², diameter ≤ 25 mm, spaced ≥ 300 mm apart
• Warp: ≤ 1.5 mm per meter length

Manufacturing Cycle (Clause 8.2.2(b))

• 6 cycles of:
  • 8 hours boiling in water
  • 16 hours drying at 65 ± 5°C oven

flowchart TD
    A[Raw Veneers] --> B[Drying to 5-15% Moisture]

IS 14616: Key Dimensions & Tolerances for LVL

Dimensions (Clause 6.1 & 6.2)

• Margin for dressing & finishing:
  • Width & Thickness: ≤ 3 mm
  • Length: ≤ 12 mm
• Supplied LVL dimensions include margin unless finished size is ordered.

Workmanship Tolerances (Clause 7)

Strength & Physical Requirements (Clause 8.2.3 & Table 1)

Summary Diagram: Tolerances & Dimensions

graph TD
  A[LVL Dimensions] --> B[Width & Thickness Margin ≤ 3mm]
  A --> C[Length Margin ≤ 12mm]
  D[Workmanship Defects] --> E[Jointing gaps ≤ 3mm]
  D --> F[Slope of grain ≤ 1:10]
  D --> G[Tight knots ≤ 3 per m², ≤25mm dia]
  D --> H[Warp ≤ 1.

IS 14616: Workmanship and Finish for LVL

Key Specifications (Clause 7 & 6.2)

• Margin for dressing/finishing:
  • Width & thickness: ≤ 3 mm
  • Length: ≤ 12 mm
• Permissible defects:

Strength Requirements (Clause 8.2.3, Table 1)

Summary Diagram of Permissible Defects

graph LR
A[LVL Panel] --> B[Jointing gaps ≤ 3mm, staggered]
A --> C[Slope of grain ≤ 1:10 in face layers]
A --> D[Tight knots ≤ 3 per m², ≤ 25mm dia, spaced ≥ 300mm]
A --> E[Warp ≤ 1.5 mm/m length]

Note: Dimensions supplied include finishing margin unless specified as finished components. Testing per

IS 14616: Sampling and Testing Key Points

1. Sampling (Clause 8.1)

Samples are drawn randomly from batches as per:

Refer IS 7638:1999 for detailed sampling methods.

2. Testing (Clause 8.2.3 & Table 1)

3. Testing Conditions

• Strength tests on six specimens each.
• Conditioning includes 6 cycles of 8h boiling + 16h drying at 65 ± 5°C.

Summary Diagram of Testing Flow

flowchart TD
    A[Sample Selection as per Batch Size] --> B[Conditioning: 6 Cycles Boiling & Drying]
    B --> C[Strength Tests on 6 Specimens]
    C --> D[Evaluate Properties vs Table 1 Requirements]
    D --> E{Pass or Fail}

This ensures quality and conformity of Laminated Veneer

IS 14616: General Requirements for Laminated Veneer Lumber (LVL)

Key Specifications (Clause 9.1, 8.2.3, 8.2.4)

Testing Standards

• Tests per IS 1708 (Parts 6, 8, 9, 11, 12, 15)
• Swelling per IS 2380 (Part 17)

Summary Diagram of Mechanical Properties

graph LR
A[LVL Properties] --> B[Modulus of Rupture: 50 N/mm²]
A --> C[Modulus of Elasticity: 7,500 N/mm²]
A --> D[Compressive Strength]
D --> D1[Parallel to Grain: 35 N/mm²]
D --> D2[Perpendicular to Laminae: 50 N/mm²]
A --> E[Horizontal Shear]
E --> E1[Parallel: 6 N/mm²]
E --> E2[Perpendicular: 8 N/mm²]
A --> F[Tensile Strength: 55 N/mm²]
A --> G[Screw Holding Power]
G --> G1[Edge: 2,

IS 14616: Marking and Certification Key Points

Marking (Clause 9.1)

Each LVL piece must be legibly and indelibly marked near one corner with:

• Manufacturer's name or trade-mark
• Thickness
• Year of manufacture
• Eco-Mark labelling criteria (if applicable)

BIS Certification Marking (Clause 9.2)

• LVL may carry the BIS Standard Mark as per the Bureau of Indian Standards Act, 1986.
• Use of Standard Mark is subject to BIS licensing conditions.
• LVL should be delivered in good condition and properly packed.

Referenced IS Standards (Annex A)

These govern test methods and properties relevant to LVL:

Summary Table for Marking Requirements

This ensures traceability, quality assurance, and compliance with BIS regulations for laminated veneer lumber.

IS 14616: Additional Requirements for Eco-Mark (Summary)

Environmental Compliance (Clause 9.1.2):

• Manufacturer must obtain environmental consent clearance from the State Pollution Control Board.
• Compliance with:
  • Water (Prevention and Control of Pollution) Act, 1974 & 1977
  • Air (Prevention and Control of Pollution) Act, 1981
  • Environment (Protection) Act, 1986 (authorization if required)
• Must align with Forest Department rules.

Specific Requirements (Clause 9.2):

• Laminated Veneer Lumber (LVL) must meet Eco-Mark specific criteria outlined in relevant standard clauses.
• Manufacturer must submit documentary evidence (certificate/declaration) to BIS when applying.

Testing Requirements (Clause 8.2.3):

• Test 6 specimens each for:
  • Modulus of Rupture (MOR)
  • Modulus of Elasticity (MOE)
  • Compressive strength (parallel & perpendicular to grain)
  • Horizontal shear strength (parallel & perpendicular)
  • Tensile strength parallel to grain
  • Nail and screw holding power
• Tests per IS 1659, IS 1708 (various parts), IS 1734 (Part 9)
• Average values must conform to Table 1 (mechanical property limits).

Key Notes for Eco-Mark Certification:

• Eco-Mark is an optional label combined with ISI Mark.
• Based on MoEF Gazette Notification No. 170, May 18, 1996.
• Requires environment-friendly manufacturing and product characteristics.

Typical Mechanical Property Test Setup (Fig. 1):

graph TD
A[Compressive Strength Tests] --> B[Parallel to Grain]
A --> C[Perpendicular to Grain & Parallel to Laminate]
A --> D[Perpendicular to Grain & Perpendicular to Laminate]

For detailed mechanical values, refer to Table 1 of IS 14616:1999 and related test methods in IS 1659 and IS 1708.

IS 14616: List of Referenced Indian Standards for Laminated Veneer Lumber (LVL)

Key Notes:

• Clause 8.1: Sampling and conformity criteria as per IS 7638.
• Clause 9.2.1: Use of BIS Standard Mark regulated by BIS Act 1986.
• LVL is engineered from plantation wood to overcome natural timber defects.
• Testing covers static bending, tensile, compressive, shear strengths parallel/perpendicular to grain, moisture, density, and swelling.

Typical strength testing methods referenced (IS 1708 series):

flowchart LR
    A[LVL Material] --> B[Testing as per IS 1708 Parts]
    B --> C{Strength Tests}
    C --> D[Static Bending]
    C --> E[Compressive Parallel]
    C

IS 14616: Test Methods for Micro-organism Resistance & Mechanical Properties of LVL

Micro-organism Resistance Test (Annex B, Clause 8.2.2)

• Specimen Preparation (Clause 2.2):
  Sawdust is inoculated with spores of wood-destroying fungi and loosely compacted. Test specimens are pressed so their top surfaces align with the sawdust surface.

• Incubation (Clause 2.3):
  The dish is covered with glass and sealed with modeling clay to maintain saturated water vapor atmosphere, promoting fungal attack.

Mechanical Properties & Strength Requirements (Clause 8.2.3 & Table 1)

Notes:

• Strength tests must follow IS 1708 parts for respective properties.
• Average values from six specimens must meet or exceed above requirements.
• Micro-organism resistance test ensures glue line durability against fungal attack.

flowchart TD
    A[Prepare Sawdust with Fungal Spores] --> B[Press Specimens into Sawdust]
    B -->

IS 14616: Committee Composition - Key Points

Committee Composition is detailed in Annex C of IS 14616, specifying members from diverse organizations related to wood products, plywood, forestry, packaging, government departments, and research institutes.

Highlights:

• Chairman: Shri V. Sivananda, Indian Plywood Industries Research and Training Institute, Bangalore
• Members: Representatives from:
  • Indian Plywood Industries Research and Training Institute
  • Public Works Departments (various states)
  • Forest Departments
  • Plywood Manufacturers' Associations
  • Directorate General of Technical Development
  • Indian Institute of Packaging
  • Directorate General of Supplies & Disposals
  • Federation of Indian Plywood and Panel Industry
  • Central Public Works Department
  • National Test House
  • Ministry of Defence (R&D)
  • Indian Institute of Architects
  • Ministry of Railways (RDSO)
  • Various plywood and timber manufacturing companies
  • Research Institutes like Forest Research Institute (FRI), Institute of Wood Science and Technology, Central Building Research Institute (CSIR)

Purpose:

• To guide the formulation of standards for Laminated Veneer Lumber (LVL) and other reconstituted ligno-cellulosic wood products.
• To ensure representation from technical, manufacturing, research, and regulatory bodies for balanced standard development.

No standard formulas or tables are specified under Committee Composition.

If you need formulas or tables related to LVL design or testing, please specify, and I can provide relevant IS code references or engineering formulas.

graph TD
A[Committee Chair] --> B[Technical Institutes]
A --> C[Government Departments]
A --> D[Manufacturers & Associations]
A --> E[Research Organizations]
B --> F[IPIRTI Bangalore]
C --> G[Public Works Dept]
C --> H[Ministry of Defence]
D --> I[Plywood Manufacturers]
E --> J[FRI Dehra Dun]
E --> K[IWST Bangalore]

This diagram shows the broad representation in the committee for comprehensive standard development.