Method of fire resistance test of firestops

IS 12458: Scope - Key Formulas, Tables, and Specifications

1. Size Coverage (Clause 4.1.1)

• Size 450 x 560 mm covers all sizes up to and including 450 x 560 mm (area ≤ 0.25 m²).
• Size 800 x 1250 mm covers all sizes up to and including 800 x 1250 mm (area ≤ 1 m²).
• Components of smaller sizes must not be smaller than those specified for these sizes.

2. Hose Stream Test (Clause 5.1.2 & Table 2)

• Nozzle orifice distance: 6 m from specimen center.
• Stream directed slowly over entire exposed surface.

3. Furnace Temperature Rise (Clause 3.1.1 & Table 1)

• Minimum 5 thermocouples required for temperature measurement.

This summary covers essential scope-related sizes, test conditions, and temperature profiles per IS 12458.

IS 12458: Testing Equipment and Apparatus - Key Points

Testing Conditions (Clause 3.3)

• Ambient temperature at test start: 20°C to 40°C
• Protect equipment and sample from abnormal wind/weather.

Furnace Temperature Profile (Clause 3.1.1 - Table 1)

• Minimum 5 thermocouples required for temperature measurement.

Hose Stream Equipment (Clause 2.4)

• Must apply hose stream immediately post-fire exposure per Clause 5.1.2.

Test Report Requirements (Clause 6.1)

• Assembly description & fixing arrangement with drawings.
• Firestop rating.
• Manufacturer's name and trade name.
• Observations during and after fire test.

flowchart TD
    A[Sample Preparation] --> B[Testing Conditions]
    B --> C{Temperature Range 20-40°C}
    C --> D[Furnace Heating per Table 1]
    D --> E[Temperature Measurement (≥5 Thermocouples)]
    E --> F[Fire Exposure]
    F --> G[Hose Stream Application]
    G --> H[Test Observations & Reporting]

Summary: Maintain controlled ambient conditions, follow furnace temperature-time curve, use adequate thermocouples, apply hose stream post-fire, and document test details thoroughly.

IS 12458: Standard Heating and Pressure Conditions

1. Standard Heating Conditions (Clause 3.1.1)

• Temperature Rise Formula:

[ T - T_0 = 345 \log_{10}(8t + 1) ]

Where:

• (T) = Furnace temperature at time (t) (°C)
• (T_0) = Initial furnace temperature (°C)
• (t) = Time in minutes

This formula defines the Standard time-temperature rise curve used to simulate fire exposure.

2. Pressure Conditions (Clause 3.2)

• Pressure conditions during fire testing are maintained as per the requirements to simulate realistic fire scenarios. Specific values depend on test setup but must comply with Clause 5.1.2 regarding hose stream application.

3. Hose Stream Equipment (Clause 2.4)

• Equipment must apply a hose stream immediately after fire exposure to assess structural integrity under sudden cooling.

4. Example Table: Temperature Rise vs Time (from Table 1)

Visual Summary: Time-Temperature Curve

graph LR
A[Start: T = T₀] --> B[Increase temperature according to T - T₀ = 345 log₁₀(8t+1)]
B --> C[Apply hose stream immediately after fire exposure]

Use this curve and conditions to design and test structural elements for fire resistance as per IS 12458.

IS 12458: Test Specimens - Key Specifications & Guidelines

• Conditioning (Clause 4.2):
  Test specimens must be conditioned for 7 days before testing to ensure moisture and temperature equilibrium.

• Testing Environment (Clause 3.3):

  • Protect specimens and equipment from abnormal wind/weather.
  • Ambient temperature at test start: 20°C to 40°C.

• Pressure Measurement (Clause 3.2.2):

  • For horizontal specimens, measure pressure at 100 mm below the underside surface.
  • For vertical specimens, measure at approx. 3/4 height of the specimen.

• Temperature Measurement (Clause 3.1.4):

  • Use thermocouples with wire diameter ≤ 0.7 mm for surface temperature measurement.

Summary Table

flowchart LR
    A[Test Specimen] --> B[Conditioning: 7 days]
    B --> C[Testing Environment: 20-40°C]
    C --> D{Specimen Orientation}
    D -->|Horizontal| E[Pressure @ 100 mm below]
    D -->|Vertical| F[Pressure @ 3/4 height]
    E --> G[Temperature Measurement]
    F --> G
    G --> H[Thermocouple ≤ 0.7 mm]

This ensures reliable and standardized test results per IS 12458.

IS 12458: Procedure and Rating for Hose Stream Test

Key Specifications (Clause 5.1.2 & Table 2)

• Hose Diameter: 63 mm
• Nozzle Distance: 6 m from specimen center
• Nozzle Type: Stand pipe as per IS: 903-1984
• Application: Stream directed slowly over entire exposed surface, starting at center

Table 2: Water Pressure & Duration for Hose Stream Test

Additional Notes

• Drying Temperature: ≤ 60℃ before testing (Clause 4.2.1)
• Hose Stream Equipment: Must be ready to apply immediately post-fire exposure (Clause 2.4)
• Standard Heating & Pressure: As per Clause 3.1

flowchart LR
    A[Fire Exposure] --> B[Dry Specimen (≤60℃)]
    B --> C[Apply Hose Stream]
    C --> D{Duration & Pressure}
    D --> |>240 ≤480 min| E[310 kPa, 32 s/m²]
    D --> |>120 ≤240 min| F[210 kPa, 16 s/m²]
    D --> |>90 ≤120 min| G[210 kPa, 9.7 s/m²]
    D --> |≤90 min| H[210 kPa, 6.5 s/m²]
    E & F & G & H --> I[Complete Test]

This ensures standardized hose stream impact for evaluating fire resistance.

IS 12458: Test Report Key Requirements (Clause 6.1)

The Test Report for firestop assemblies must include:

• a) Assembly Description:

  • Fixing arrangement of firestop
  • Drawings showing exact component size and firestop location within assembly

• b) Firestop Rating:

  • Fire resistance rating of each firestop (e.g., duration in minutes/hours)

• c) Manufacturer Details:

  • Name of manufacturer
  • Trade name of the product

• d) Observations:

  • Observations during the test
  • Condition after furnace fire extinguishment

Important Related Specifications

• Ambient temperature at test start: 20 to 40°C (Clause 3.3)
• Drying temperature limit for specimens: ≤ 60°C (Clause 4.2.1)
• Minimum thermocouples: 5 for temperature measurement (Clause 3.1.1)

This ensures consistent, reliable firestop testing and documentation per IS 12458.