Laying of Plastic Translucent Sheets Made from Thermosetting Polyester Resin (Glass Fibre Reinforced) Alone or in Conjunction with Asbestos Cement Sheets/Steel Sheets/Aluminium Sheets - Code of Practice

IS 15224: Scope - Key Points & Specifications

• Purpose: Efficient planning and execution of roofing work.

• Essential Inputs (Clause 4.1):

  • Roof Area: Total area to be covered.
  • Daylight Factor: Required natural light penetration.
  • Sub-Structure Details: Designed considering wind loads.
  • Roof Pitch: Slope angle of the roof.
  • Openings & Accessories: Location, size, and details.

• Rounding Off (per IS 2:1960):

  • Final test or calculation values must be rounded to match the precision of specified values.

• Referenced Standards:

  • Annex A lists related Indian Standards essential for compliance.
  • Always verify the latest editions for current applicability.

No direct formulas or tables in the scope clause. Use these inputs for design calculations per related IS codes (e.g., IS 875 for wind loads).

flowchart TD
    A[Start: Project Planning] --> B{Gather Data}
    B -->|Roof Area| C[Calculate Material Quantity]
    B -->|Daylight Factor| D[Design Openings]
    B -->|Sub-Structure Details| E[Wind Load Analysis]
    B -->|Roof Pitch| F[Structural Design]
    B -->|Openings & Accessories| G[Detailing & Installation]
    C & D & E & F & G --> H[Execution of Roofing Work]

IS 15224 Key References & Tables for Plastic Translucent Sheets Roofing

1. Support Centres for Plastic Translucent Sheets (Clause 6.1.3.1 & 6.1.3.2)

• Deflection Limits:

  • Wind gusts: max deflection = span/15, max 100 mm
  • Superimposed loads: max deflection = span/30, max 50 mm

• Fixing considerations:

  • Prevent sheet pull-over at fasteners.
  • Avoid ovalling/tearing of fixing holes.
  • Prevent lap openings and sealant damage.

2. Table 1: Max Recommended Purlin/Rail Centres for Full Roof Covering

3. Table 2: Max Recommended Purlin/Rail Centres for Partial Layouts (Chequerboard or Eaves to Ridge)

IS 15224 Key Definitions & Tables

1. Definitions

• Daylight Factor (Clause 3.17):
  Percentage ratio of indoor illuminance to simultaneous outdoor illuminance, used for daylight design.

2. Purlin/Rail Spacing for Plastic Translucent Sheets (Clause 6.1.3.2)

3. Purlin/Rail Spacing for Partial Chequerboard or Eaves to Ridge Layouts

4. Rounding Off (General)

• Follow IS 2:1960 for rounding numerical values.
• Retain significant digits as per the

IS 15224 – General Requirements: Key Formulas, Tables & Specifications

1. Purlin/Rail Spacing for Plastic Translucent Sheets (Clause 6.1.3.2)

2. Purlin/Rail Spacing for Partial Layouts (Table 2, Clause 6.1.3.2)

3. **Fixing Accessories: Number & Length of Bolts (Clause 7.2.9 & 7.2.10, Table 3

IS 15224: Key Formulas, Tables, and Specifications for Materials

1. Plastic Translucent Sheets (Thermosetting Polyester Resin, Glass Fibre Reinforced)

Support Centres (Clause 6.1.3.1 & Tables 1 & 2)

• Deflection Limits:
  • Wind gusts: ≤ span/15 & ≤ 100 mm
  • Superimposed loads: ≤ span/30 & ≤ 50 mm
• Maximum Recommended Purlin/Rail Centres (mm):

2. Fixing Accessories (Clause 7.2.9 & Table 3)

IS 15224: Roof Design & Support Key Points

1. Planning Inputs (Clause 4.1)

• Roof area to cover
• Required daylight factor
• Sub-structure details (wind load design)
• Roof pitch
• Location/size of openings & accessories

2. Roof Pitch (Clause 6.1.2)

• Pitch affects drainage, wind resistance, and structural behavior.
• Typical values depend on roofing type; ensure compatibility with sheet profiles.

3. Purlin/Rail Spacing (Clause 6.1.3.2)

• Table 1: Max spacing for fully laid plastic translucent sheets (glass fibre reinforced)

• Table 2: Max spacing for partial chequerboard or eaves-to-ridge layouts

IS 15224: Laying and Fixing of Plastic Translucent Sheets (Thermosetting Polyester Resin, Glass Fibre Reinforced)

Key Specifications & Procedures

• Mitred Corners (Clause 6.1.6.1):
  Where four corners of sheets overlap, two sheets must be mitred to ensure a perfect fit (see Fig. 4 in the code).

  • Applies also when plastic sheets overlap with asbestos cement, steel, or aluminium sheets in chequerboard or eaves-to-ridge layouts.

• Purlin/Rail Spacing (Clause 6.1.3.2):
  Maximum recommended purlin spacing depends on sheet type and profile:

• Partial Laying with Other Sheets (Table 2):
  Slightly larger purlin spacing allowed when laid partially in chequerboard or eaves-to-ridge layouts.

• Pre-laying Checks (Clause 7.3.1):
  Verify purlin spacing and sheet length to ensure proper laps and overhang at eaves.

Summary Diagram: Sheet Overlap & Mitring

flowchart LR
    A[Four Sheet Corners Overlap] --> B{Mitre Two Sheets?}
    B -- Yes --> C[Perfect Fit Achieved]
    B -- No --> D[Poor Fit, Possible Leakage

IS 15224: Fixing of Accessories - Key Specifications & Tables

1. Accessories Specification

• Fixing accessories (hooked, cranked, U, J, square bend hook bolts, L-bolts, roof washers) shall conform to IS 730.

2. Bolts & Washers for Stitching Side Laps (Clause 7.2.10, Table 3)

*Includes galvanized iron bolts, bituminous felt washers, and galvanized iron washers.

3. Additional Notes

• For plastic translucent sheets combined with asbestos/steel/aluminium sheets, follow the respective code’s fixing requirements.
• Bolt length = Depth of purlin + allowance (65 or 90 mm depending on sheet type).

Summary Diagram of Bolt Fixing

flowchart LR
    A[Sheet Side Lap] --> B[Galvanized Iron Bolt]
    B --> C[Bituminous Felt Washer]
    B --> D[Galvanized Iron Washer]
    C & D --> E[Purlin]
    E --> F[Structural Support]

This ensures secure fixing with proper sealing and load transfer.

Use IS 730 for accessory details and IS 15224 Table 3 for bolt/washers count and length.

Gutters and Rainwater Pipes (IS 15224 Highlights)

• Clause 9.1: Fix gutters and rainwater pipes as per relevant IS codes (e.g., IS 875, IS 2064).
• Gutters are defined as roof water channels (Clause 3.8).

Key Specifications (from IS 15224 & related IS codes)

Formula for Rainwater Pipe Size (Approximate)

[ Q = A \times I ]

• (Q) = runoff volume (liters/sec)
• (A) = roof area (m²)
• (I) = rainfall intensity (mm/hr)

Select pipe diameter to carry (Q) with velocity 0.6-3 m/s.

Diagram: Gutter and Rainwater Pipe System

flowchart TD
    Roof --> Gutter
    Gutter --> Downpipe
    Downpipe --> Drainage
    Gutter -. slope .-> Downpipe

Notes:

• Refer IS 2064 for GI gutters and pipes.
• Use Table 6.1.3.2 from IS 15224 for purlin spacing when fixing translucent sheets near gutters.
• Ensure proper sealing at joints to avoid leakage.

For detailed design, consult IS 2064 and IS 875 (Part 3).

IS 15224: Storage at Site - Key Points

Clause 10.1 - Storage of Plastic Translucent Sheets (Thermosetting Polyester Resin, Glass Fibre Reinforced)

• Store sheets on flat, clean battens.
• Battens spacing: ≤ 1500 mm centers.
• Stack height: ≤ 1000 mm.
• Ground must be firm and level.

Tables for Purlin/Rail Spacing (Clause 6.1.3.2)

Notes:

• For chequerboard or eaves-to-ridge layouts, max purlin centres increase (see Table 2 in clause 6.1.3.2).
• Ensure firm, level storage to avoid deformation.
• Follow relevant IS codes for fixing gutters and rainwater pipes (Clause 9.1).

flowchart TD
    A[Storage at Site] --> B[Flat Clean Battens]
    B --> C[Battens ≤ 1500 mm centers]
    A --> D[Stack Height ≤ 1000 mm]
    A --> E[Firm Level Ground]
    F[Purlin Spacing] --> G[Refer Tables 6.1.3.2]
    G --> H[Depends on Sheet Type & Profile]

IS 15224 Safety Precautions Summary

Key Safety Points

• Protection from Wind & Damage: Plastic translucent sheets (thermosetting polyester resin, glass fiber reinforced) must be secured against wind uplift and mechanical damage (Clause 10.2).
• Storage: Always cover sheets with waterproof covers when stored outdoors to prevent moisture entrapment and discoloration due to solar heating.
• General Safety: Follow safety provisions from respective codes for asbestos cement, steel, and aluminum sheets (Clause 11.3).

Support and Deflection Limits (Clause 6.1.3.1)

• Deflection Limits:
  • Wind gusts: max deflection = Span/15, not exceeding 100 mm
  • Superimposed loads: max deflection = Span/30, not exceeding 50 mm
• Fastener Performance: Sheets must not pull over fasteners under high wind gusts.

Recommended Maximum Support Centres (from Table 1, IS 15224 referencing IS 12866)

Deflection Formula

[ \delta_{max} \leq \frac{L}{n} ] Where:

• (\delta_{max}) = maximum deflection
• (L) = span length
• (n = 15) (wind load), or (30) (superimposed load)

flowchart TD
    A[Plastic Translucent Sheets] --> B[Protection from Wind & Damage]
    A --> C[Covered Storage]
    A --> D[Follow Safety Codes for Fixing]
    B --> E[Limit Deflection]
    E --> F[Span/15 for Wind]
    E --> G[Span/30 for Loads]
    F --> H[Max 100 mm]
    G --> I[Max 50 mm]

Note: Always refer to IS 2:1960 for rounding off test values.

IS 15224 - Cleaning and Maintenance Key Points

Cleaning (Clause 12.1)

• For plastic translucent sheets (thermosetting polyester resin, glass fibre reinforced):
  • Clean periodically with warm water + mild detergent.
  • Remove persistent stains by gentle brushing with a bristle brush.
  • Remove tar/grease with white spirit or acetone solvent.

Maintenance (Clause 12.2)

• To maintain appearance, clean & dry sheets may be coated with clear, water-white air-drying lacquer.

When used with asbestos cement/steel/aluminium sheets (Clause 12.5)

• Follow cleaning & maintenance procedures as per respective IS codes for those materials.

Summary Table: Cleaning Agents & Methods

Referenced IS Codes for Related Materials

• IS 459: Asbestos cement sheets
• IS 277: Galvanized steel sheets
• IS 1254: Corrugated aluminium sheets

flowchart LR
    A[Plastic Translucent Sheets] --> B{Cleaning Required?}
    B -- Yes --> C[Warm water + Mild detergent]
    C --> D{Stains Persist?}
    D -- Yes --> E[Brush gently]
    E --> F{Tar/Grease?}
    F -- Yes --> G[White spirit / Acetone]
    F -- No --> H[Dry sheets]
    D -- No --> H
    H --> I[Apply clear lacquer (optional)]

Note: Always follow safety precautions as per relevant IS codes for asbestos cement/steel/aluminium sheets when used in combination.

IS 15224: List of Referred Indian Standards (Key Specifications)

The standard refers to various Indian Standards (IS) for materials used in roofing and cladding, ensuring compatibility and quality.

Important Notes:

• These IS codes govern material quality, dimensions, and installation practices.
• For cleaning and maintenance (Clause 12.5), follow respective codes for asbestos cement, steel, and aluminium sheets when used with plastic translucent sheets.
• Always check for the latest edition of these IS codes for updated provisions.

Quick Reference Table for Roofing Sheets

flowchart TD
    A[IS 15224] --> B[Material Specifications]
    B --> C[Galvanized Steel - IS 277]
    B --> D[Asbestos Cement - IS 459]
    B --> E[Aluminium Sheet - IS 1254]
    B --> F[Plastic Translucent Sheets - IS 12866]
    B --> G[Fasteners - IS 730, IS 1120]

Summary: Use these referenced IS codes as the basis for material selection, quality control, and installation

Committee Composition (IS 15224 - Annex B)

The Committee responsible for formulation of IS 15224 is the Flooring, Wall Finishing and Roofing Sectional Committee, CED 5. Key details:

• Chairman: Shri P. B. Vijay (Personal Capacity)
• Members represent diverse organizations such as:
  • All India Brick & Tile Manufacturers Federation
  • Central Building Research Institute, Roorkee
  • Builder's Association of India
  • Ministry of Railways (RDSO), Lucknow
  • Indian Institute of Technology, Kharagpur
  • Various industry leaders and government departments

The committee includes experts from industry, research institutes, government bodies, and technical organizations ensuring a comprehensive standard.

Key Tables for Purlin/Rail Spacing (Clause 6.1.3.2)

Notes:

• For plastic translucent sheets laid with asbestos/steel/aluminium sheets in chequerboard or eaves-to-ridge layouts, follow the **