Method of test for laboratory determination of air permeability of joints in buildings

IS 11818 - Scope Summary

IS 11818 covers the testing of joint installations in construction components, focusing on dimensional deviations and their effects.

Key Points from Clause 8.1:

• Tests are conducted on joints under four conditions:
  1. Nominal joint width with adjacent surfaces correctly aligned.
  2. Minimum specified joint width with correct alignment.
  3. Maximum specified joint width with correct alignment.
  4. Joint width varying from minimum to maximum with adjacent components misaligned perpendicularly within limits.

Implications:

• Ensures joint performance under realistic installation tolerances.
• Helps verify joint durability, flexibility, and sealing under dimensional variations.

Typical Parameters (from general practice):

flowchart LR
    A[Joint Installation] --> B{Joint Width}
    B --> C[Minimum Specified Width]
    B --> D[Nominal Width]
    B --> E[Maximum Specified Width]
    B --> F[Variable Width with Misalignment]
    C & D & E & F --> G[Performance Testing]

This scope ensures joints meet functional requirements despite installation variations.

IS 11818: Field of Application - Summary

IS 11818 primarily deals with testing methods for air permeability of windows and doors. It references related International Standards (ISO 6613, ISO 6589) for detailed procedures.

Key Points on Field of Application:

• Applicable to windows and door height windows.
• Focuses on air permeability tests under controlled differential pressure.
• Covers devices for rapid controlled changes in differential pressure.
• Relevant for evaluating intersections of joints in fenestration.

Important References:

Typical Test Setup (Conceptual):

flowchart LR
    A[Pressure Source] --> B[Device for rapid controlled pressure change]
    B --> C[Window/Door specimen]
    C --> D[Measurement of air flow rate]
    D --> E[Calculate air permeability]

Formula for Air Permeability (General form):

[ q = \frac{Q}{A} ]

• q = Air permeability (m³/s·m²)
• Q = Air flow rate through specimen (m³/s)
• A = Area of the specimen (m²)

This standard guides the testing procedure rather than specifying design criteria. For detailed test methods, refer to the mentioned ISO standards.

IS 11818: Definitions - Key Points

IS 11818 (1986) aligns with ISO 6589 (1983) and refers to terms related to air permeability testing of windows and doors.

Key Definitions (from IS 11818 and ISO 6589):

• Air Permeability: Rate of air flow through a unit area of the specimen under a specified pressure difference.
• Differential Pressure Device (Clause 5.3): Equipment enabling rapid, controlled changes in pressure difference within defined limits for testing.
• Intersection of Joints: Points where two or more joints meet, critical for leakage evaluation.

Related Standards:

• ISO 6613: Details air permeability test methods for windows and doors.
• IS 11818 references ISO 6589 for terminology and test procedures.

Typical Formula for Air Permeability:

[ q = \frac{Q}{A} ] Where:

• ( q ) = Air permeability (m³/h·m²)
• ( Q ) = Air flow rate through specimen (m³/h)
• ( A ) = Area of specimen (m²)

Summary Table: Air Permeability Test Parameters

flowchart LR
    A[Start: Setup Differential Pressure Device] --> B[Apply Pressure Difference]
    B --> C[Measure Air Flow Rate Q]
    C --> D[Calculate Air Permeability q = Q / A]
    D --> E[Evaluate Leakage at Joints and Intersections]
    E --> F[End: Report Results]

This concise overview covers the definitions and key parameters related to air permeability testing as per IS 11818. For detailed procedures, refer to the full standard and ISO 6613.

IS 11818: Test Apparatus for Air Permeability of Joints

Key Clauses & Specifications

• Clause 5.3: Device must enable rapid controlled changes of differential pressure within defined limits (max differential pressure typically <600 Pa or >600 Pa).
• Clause 5.4: Apparatus must measure air flow into/out of the test chamber accurately.

Test Procedure Highlights (Clause 8.4 & 9)

• Test joints under positive and negative differential pressures by reversing joint orientation.
• Record air permeability (m³/h) to nearest 0.1 m³/h.
• Report the higher flow reading from increasing and decreasing pressure phases.
• Express results:
  • Per metre length of joint.
  • Per junction location.
  • Per unit surface area if joint distribution is known.

Reporting Requirements

Include in the test report:

• Diagram of test apparatus.
• Installation details of test joint.
• Ambient temperature during test.
• Extraneous leakage measurement and correction.
• Joint construction details with sectional diagrams.
• Test results plotted vs differential pressure.
• Testing organization and date.
• Simulated ageing cycles, if any.
• Explicit validity conditions of results.

Differential Pressure Application Sequence

• Apply pressure in steps up to Pmax (≤600 Pa or >600 Pa), then reverse.

Typical Air Permeability Plot

graph LR
A[Start at 0 Pa] --> B[Increase differential pressure stepwise]
B --> C[Measure flow rate at each step]
C --> D[Decrease differential pressure stepwise]
D --> E[Measure flow rate again]
E --> F[Plot flow vs pressure]

Summary Table: Differential Pressure Limits

This ensures repeatable, accurate air permeability testing of joints per IS 11818.

IS 11818: Preparation of Joint for Testing – Key Points

1. Installation of Joint (Clause 6)

• Joint installed between actual components to withstand test pressures without impairing performance.
• Surrounding components must simulate real surface conditions, including irregularities.
• For positive differential pressure, joint's external surface forms part of the chamber's internal face; reversed for negative pressure (Clause 8.3).

2. Measurement of Extraneous Air Leakage (Clause 7)

• Measure and eliminate air leakage not due to the joint.
• Measure leakage with joint sealed at test differential pressures.
• Use air metering equipment; record air temperature in lab and chamber.
• Report method of leakage measurement.

3. Test Conditions (Clause 8.1)

Test for dimensional deviations:

4. Test Procedure (Clause 8.4)

• Repeat tests with negative differential pressure by reversing joint installation.

5. Expression of Results (Clause 9)

• Air permeability recorded in m³/h, to nearest 0.1.
• Record highest flow during increasing and decreasing pressure phases.
• Express results:
  • Per metre length of joint.
  • Per junction location.
  • Flow per unit surface if joint distribution known.
• Plot air permeability vs. differential pressure.
• Correct for extraneous leakage.

6. Test Report Must Include

• Diagram of test apparatus.
• Joint installation details.
• Ambient and chamber air temperature.
• Extraneous leakage method and values.
• Joint description with sectional diagrams.
• Test results.
• Testing organization and date.
• Simulated ageing cycles if any.
• Statement on validity conditions.

Summary Table of Differential Pressure Application (Figure Reference)

flowchart TD
    A[Install Joint Between Components] --> B

IS 11818 — Preparation for Test: Key Points & Specifications

1. Joint Installation (Clause 6)

• Joint must be installed between actual components to withstand test pressures without harmful deflection.
• Surrounding components should simulate real surface conditions, including irregularities affecting air permeability.
• For positive differential pressure, joint's external surface forms part of the internal face of the test chamber wall; reversed for negative pressure.

2. Extraneous Air Leakage (Clause 7)

• Measure and preferably eliminate extraneous air leakage not due to the joint.
• Leakage measured with the joint sealed at test differential pressures.
• Use the same or additional metering equipment for leakage measurement.
• Record air temperature of laboratory and chamber in the test report.
• Clearly state the method of air leakage measurement in the report.

3. Test Conditions for Dimensional Deviations (Clause 8.1)

• Test for:
  • Nominal joint width, aligned surfaces.
  • Minimum joint width, aligned surfaces.
  • Maximum joint width, aligned surfaces.
  • Variable joint width with misaligned adjacent components (perpendicular to faces).

Summary Table: Test Preparation Checklist

flowchart TD
    A[Start: Joint Installation] --> B[Simulate real surface conditions]
    B --> C{Pressure Type?}
    C -->|Positive| D[Joint surface = internal chamber face]
    C -->|Negative| E[Joint surface = external chamber face]
    D --> F[Seal joint for leakage test]
    E --> F
    F --> G[Measure extraneous leakage]
    G --> H[Record air temperature]
    H --> I[Test at nominal, min, max widths]
    I --> J[Test with misalignment]
    J --> K[Complete test & report]

This preparation ensures reliable, repeatable air permeability testing of joints per

IS 11818: Test Procedure for Air Permeability of Joints

Key Steps & Specifications:

• Test Setup:

  • Install joint between actual components to resist test pressures without deformation.
  • For positive differential pressure, joint’s external surface forms part of the chamber's internal wall; reverse for negative pressure (Clause 6, 8.4).

• Pressure Application:

  • Apply differential pressure up to max 600 Pa (or >600 Pa if required).
  • Rapid controlled pressure changes between defined limits (Clause 5.3).
  • Measure differential pressure accurately across joint surfaces (Clause 5.5).

• Extraneous Leakage:

  • Measure and correct for any leakage not due to the joint with specimen sealed (Clause 7).

• Recording Results (Clause 9):

  • Record air permeability (m³/h) to nearest 0.1 m³/h.
  • Report higher flow reading from increasing and decreasing pressure phases.
  • Express permeability:
    • Per metre length of joint
    • Per junction location
    • Per unit surface area if joint distribution known
  • Plot air permeability vs. differential pressure graph.

• Test Report Must Include:

  • Diagram of apparatus and joint installation
  • Ambient temperature during test
  • Extraneous leakage values at each pressure
  • Joint construction details with sectional diagrams
  • Test results and conditions
  • Testing organization and date
  • Simulated ageing cycles (if any)

Typical Formula for Air Permeability:

[ Q = \frac{V}{t} ]

• (Q) = air flow rate (m³/h)
• (V) = volume of air passed
• (t) = time of measurement (h)

Pressure Sequence (Conceptual):

graph LR
A[Start at 0 Pa] --> B[Increase pressure to Pmax]
B --> C[Decrease pressure back to 0 Pa]
C --> D[Reverse joint orientation for negative pressure]
D --> E[Repeat pressure cycle]

This procedure ensures reliable, repeatable measurement of joint air permeability under realistic conditions per IS 11818.

IS 11818 Key Points on Differential Pressure Application

Definitions (Clause 4.1)

• Differential Pressure (ΔP):
  [ \Delta P = P_{\text{external}} - P_{\text{internal}} \quad (\text{Pa}) ]
• Positive when external > internal pressure; negative otherwise.

Test Procedure (Clauses 8.2 & 8.3)

Calculation of (P_{max}) (Clause 8.3)

• (P_{max}) is based on wind velocity at the joint location.
• Use wind pressure formula (not in IS 11818 but standard practice):

[ P = 0.6 \times V^2 \quad \text{(Pa, where } V \text{ is wind velocity in m/s)} ]

Device Requirement (Clause 5.3)

• Use a device capable of rapid controlled changes in differential pressure within defined limits.

Summary Diagram of Pressure Application Sequence

sequenceDiagram
    participant TestChamber
    participant Joint

    Note over TestChamber,Joint: Step 1: 3 pulses to 1.1×Pmax (≥500 Pa)
    TestChamber->>Joint: Apply pulse 1 (0 to 1.1×Pmax)
    Note right of Joint: Hold ≥3 s
    TestChamber->>Joint: Apply pulse 2 (0 to 1.1×Pmax)
   

IS 11818: Expression of Results (Clause 9) Summary

• Air permeability at each differential pressure is recorded to the nearest 0.1 m³/h.
• For each pressure, record the higher flow reading from increasing and decreasing phases.
• Results expressed as:
  • (a) Air permeability per metre length of each joint type.
  • (b) Air permeability for each junction location.
• If joint distribution is known, flow can be given per unit surface area of the element.
• Plot air permeability vs differential pressure graph; include in report.
• Correct for extraneous air leakage if needed (Clause 7).

Test Report Must Include:

• Diagram of test apparatus.
• Installation details of test joint.
• Ambient and chamber temperatures.
• Method and value of extraneous air leakage at each pressure.
• Detailed joint description with sectional diagrams.
• Test results as per Clause 9.
• Testing organization and test date.
• Description of any simulated ageing cycles.
• Explicit statement that results are valid only for test conditions.

Differential Pressure Application (Figure Reference)

• Pmax < 600 Pa and Pmax > 600 Pa sequences applied.

flowchart TD
    A[Test Setup] --> B[Apply Differential Pressure]
    B --> C[Measure Air Flow (m³/h)]
    C --> D[Record Higher Flow Reading]
    D --> E[Calculate Air Permeability]
    E --> F[Plot Permeability vs Pressure]
    F --> G[Prepare Test Report]

This ensures consistent, comparable air permeability data for joints under specified test conditions.

IS 11818: Test Report Requirements for Air Permeability of Joints

Key Test Report Contents (Clause 9 & 8.4)

• Air permeability recorded at each differential pressure (to nearest 0.1 m³/h).
• Record higher flow reading at each pressure (increasing & decreasing phases).
• Express air permeability:
  • Per metre length of each joint type.
  • For each junction location.
  • Optionally, flow per unit surface area if joint distribution known.
• Plot air permeability vs. differential pressure graph.
• Correct for extraneous chamber leakage (Clause 7).

Mandatory Report Details:

• Diagram/reference of test apparatus.
• Installation details of the test joint.
• Ambient air temperatures (lab & chamber).
• Method & value of extraneous air leakage at each pressure.
• Full joint description with sectional diagrams & jointing product specs.
• Test results per Clause 9.
• Testing organization & test date.
• Description of simulated ageing cycles (if any).
• Explicit statement on test condition validity.

Differential Pressure Application (Figure Summary)

• For Pmax < 600 Pa and Pmax > 600 Pa, pressure is applied in increasing and decreasing sequences.
• Repeat test with reversed joint orientation for negative differential pressure (Clause 8.4).

Additional Notes:

• Differential pressure measurement device must allow rapid controlled changes (Clause 5.3).
• Joint installed to withstand pressures without impairing performance (Clause 6).
• Extraneous leakage measured with sealed joint at test pressures (Clause 7).

Summary Table: Test Report Checklist

flowchart TD
    A[Test Setup] --> B[Measure Extraneous