Specification for heat-sensitive fire detectors for use in an automatic fire alarm system

IS 2175 - Scope and Key Specifications

IS 2175 covers methods and requirements for testing vibration and response characteristics of materials or components (typically rubber or elastomeric products).

Key Points on Scope:

• Defines testing methods for vibration (Clause 5.3, Appendix B) and time of response/directional dependence (Clause 5.11, Appendix A).
• Specifies rounding off rules for test results as per IS 2-1960 (Clause 0.9).
• Applies to materials/components where vibration damping and response behavior are critical.

Important References:

Rounding Off Rule (IS 2-1960):

• Final test values are rounded to the same number of significant digits as the specified standard value.

Summary Diagram of Test Methods in IS 2175

graph TD
  A[IS 2175 Scope] --> B[Vibration Test (5.3)]
  A --> C[Response Time & Directional Dependence (5.11)]
  B --> D[Appendix B]
  C --> E[Appendix A]
  B --> F[Tables 1 & 2]
  C --> F
  A --> G[Rounding Off (0.9) per IS 2-1960]

For detailed formulas and tables, refer to Appendices A & B in IS 2175.

IS 2175: Key Definitions & Specifications

• Clause 2.0 (Definitions):
  Provides fundamental terms related to the standard, essential for uniform understanding. These typically define terms like vibration, response time, directional dependence, etc., specific to vibration testing of isolators.

• Clause 0.9 (Rounding Off):
  Final test or analysis values must be rounded per IS 2-1960 rules, keeping the same significant figures as specified in IS 2175.

• Appendix A & B (Test Methods):

  • Appendix A: Method for time of response and directional dependence testing (Clauses 5.2, 5.6, 5.7, 5.10, 5.11).
  • Appendix B: Vibration test procedures (Clause 5.3).
    These include detailed procedures and tables (Tables 1 & 2) for test parameters and acceptance criteria.

Example: Rounding Off (IS 2-1960)

For detailed formulas and tables, refer to Tables 1 & 2 in Appendices A & B of IS 2175, which specify vibration amplitudes, frequencies, and response times for testing isolators.

IS 2175: Types and Grades of Detectors – Key Points

Types and Grades (Clause 3.1.1 & 5.1, 5.2)

• Detectors are classified into three grades based on response time:
  • Grade 1 – Fastest response
  • Grade 2 – Medium response
  • Grade 3 – Slowest response
• Response time and directional dependence are tested as per Appendix A.

Resettable Detectors (Clause 2.9)

• Resettable detectors can return to normal state after alarm without replacing components.

Testing Requirements (Clause 5.1)

• Sample size: Minimum 200 detectors per design for testing.
• Tests cover response time, directional dependence, and other parameters.
• Tests are type tests valid for production batches up to 10,000 detectors.

Response Time Requirements (from Table 3, Clause 5.2)

(Note: Exact values to be confirmed from Table 3 in the standard)

Summary Diagram: Detector Classification and Testing Flow

flowchart TD
    A[Detectors] --> B{Grades based on Response Time}
    B -->|Grade 1| C[Fast Response]
    B -->|Grade 2| D[Medium Response]
    B -->|Grade 3| E[Slow Response]
    A --> F[Resettable Detectors]
    A --> G[Testing per IS 2175]
    G --> H[Sample: ≥ 200 units]
    G --> I[Tests: Response Time, Directional Dependence]
    G --> J[Valid for production ≤ 10,000 units]

Note: Refer to Tables 1, 2, and 3 and Appendix A of IS 2175 for detailed test methods and exact numerical limits.

IS 2175 - General Requirements Summary

Key Testing Clauses & Appendices:

• Clause 5.3 & Appendix B: Vibration Test (Tables 1 & 2)
• Clause 5.4 & Appendix C: Corrosion Test (Tables 1 & 2)
• Clause 5.11 & Appendix A: Time of Response & Directional Dependence Test (Clauses 5.2, 5.6, 5.7, 5.10, 5.11)

Performance Test & Criteria (Table 2 Highlights for Non-Resettable Detectors):

Notes:

• Time of Response tests require two orientations: most favorable & least favorable.

IS 2175: Performance Tests & Criteria for Conformity

Key Testing Procedures & Criteria (Non-resettable & Resettable Detectors)

Important Specifications

• Plastic Components: Must not soften, deform or melt below 95°C (Clause 4.2).
• Time of Response Tests: Two tests at each rate of temperature rise, one with the most favorable and one with the least favorable detector orientation.
• Directional Dependence: Tested in 8 orientations to ensure consistent detector performance regardless of installation angle.

Summary Diagram: Testing Flow for Non-Resettable Detectors

flowchart TD
    A[Start Testing] -->

IS 2175: Information to be Supplied with Detectors (Clause 6.1)

Detectors must be supplied with comprehensive data to ensure correct application:

• General & Technical Features: Type, sensing principle, temperature rating, response characteristics.
• Monitoring Position: Correct installation location for optimal performance.
• Reference to Owner’s Manual: For detailed operation and maintenance.
• Test Feature Operation: Instructions if a test facility is provided.
• Maintenance Instructions: Cleaning, calibration, and servicing guidelines.
• Electrical Interface Details: Required current, voltage values, tolerances, or compatibility restrictions with control and indicating equipment.

Testing & Sampling (Clauses 5.1, 5.2.1, 5.8):

• Sample Size: For production batches ≥ 200 detectors, a random sample per Tables 1 & 2 is tested.
• Tests: Type tests per test schedule must be passed (covering up to 10,000 units).
• Supply Voltage Variation Test: Response time variation ≤ 15% or 10 s; no false alarms (Appendix E).

Key Tables (Summary)

Response Time Variation Formula (Clause 5.8)

[ \Delta t = \max \left( 0.15 \times t_0, 10 \text{ s} \right) ]

Where:

• ( t_0 ) = Response time before/after voltage variation test
• ( \Delta t ) = Maximum allowable difference in response time

flowchart TD
    A[Detector Supplied] --> B[General & Technical Info]
    A --> C[Monitoring Position]
    A --> D[Owner's Manual Reference]
    A --> E[Test Feature Operation]
    A --> F[Maintenance Instructions]
    A --> G[Electrical Interface Details]

This ensures detectors are correctly applied, tested, and maintained as per IS 2175.

IS 2175: Marking of Detectors (Clause 7.1 & 7.2)

Each detector must be legibly and indelibly marked with:

• Manufacturer's name or trade-mark
• Type and description of detector and its number
• Year of manufacture
• Grading of detector indicated by color or other means:
  • Grade 1: Green
  • Grade 2: Yellow
  • Grade 3: Red
• Indication if provided with fusible link

Optionally, detectors may carry the Standard Mark certifying compliance with BIS quality and inspection norms.

Additional Notes:

• Marking ensures traceability and compliance.
• Rounding off test results should follow IS 2-1960, retaining the same significant figures as specified.
• Corrosion test details are in Appendix C, Clause 5.4 (refer to Tables 1 and 2 in IS 2175).

Summary Table for Grading Colors:

flowchart LR
    A[Detector] --> B{Marking}
    B --> C[Manufacturer's Name]
    B --> D[Type & Description]
    B --> E[Year of Manufacture]
    B --> F[Grading]
    F --> G[Green (Grade 1)]
    F --> H[Yellow (Grade 2)]
    F --> I[Red (Grade 3)]
    B --> J[Fusible Link Indication]
    B --> K[Standard Mark (Optional)]

This ensures clear identification and quality assurance per IS 2175.

IS 2175: Method of Test for Time of Response and Directional Dependence

Key Specifications (Clause 5.11, Appendix A)

• Test Environment:

  • Wind tunnel per IS 9972-1981 Fig. 6
  • Air velocity: 0.8 ± 0.1 m/s
  • Temperature: 28°C

• Tested Detectors:

  • Detector numbers as per Tables 1 & 2
  • Tested in 8 orientations for directional dependence

Response Time Requirements (Clause 5.2, Table 3)

• Response time tested at multiple rates of rise of temperature: 5, 10, 20, 30 °C/min
• Two tests per rate: one with most favourable and one with least favourable orientation

Testing Scheme Summary (Table 2)

Method Outline (Appendix A)

1. Place detector in wind tunnel with air velocity and temperature controlled.
2. Expose detector to controlled temperature rise at specified rates.
3. Record time from start of temperature rise to detector activation.
4. Repeat for all orientations to check directional dependence.

flowchart LR
    A[Start Test] --> B[Set Wind Tunnel Conditions]
    B --> C[Select Detector & Orientation]
    C --> D[Apply Temperature Rise Rate]
    D --> E[Measure Response Time]
    E --> F{All Orientations Tested?}
    F -- No --> C
    F -- Yes --> G[Compare with Limits]
    G --> H{Pass?}
    H -- Yes --> I[Conformity Confirmed]
    H -- No --> J[Fail -

IS 2175 Vibration Test Summary (Clause 5.3 & Appendix B)

• Test Setup:

  • Detector mounted in correct operating position with indicating equipment.
  • Response time noted before vibration.

• Vibration Parameters:

  • Vertical vibration amplitude: 0.1 mm
  • Duration: 5 minutes at each frequency
  • Frequencies tested (cycles per second, c/s):
    10, 15, 20, 25, 30, 35, 40, 45, 50

• Resonance Check:

  • If resonance occurs at any frequency, vibrate at that resonant frequency for 1 hour.
  • If no resonance, vibrate at 50 c/s for 1 hour.

Key Table: Vibration Frequencies and Duration

Procedure Flowchart

flowchart TD
    A[Mount detector in operating position] --> B[Note response time]
    B --> C[Apply vertical vibration at 10 c/s for 5 min]
    C --> D{Test all frequencies 10 to 50 c/s?}
    D -->|No| E[Increment frequency]
    E --> C
    D -->|Yes| F[Check for resonance]
    F -->|Yes| G[Vibrate at resonant frequency for 1 hour]
    F -->|No| H[Vibrate at 50 c/s for 1 hour]
    G --> I[Test complete]
    H --> I

This ensures the detector's mechanical integrity and reliable operation under vibration per IS

IS 2175 Corrosion Test Summary (Clause 5.4 & Appendix C)

Corrosion Atmosphere Setup (Clause 1.2)

• Temperature: 45 ± 3°C (maintained by heater + thermostat)
• Test solution:
  • 20 g sodium thiosulphate (Na2S2O3·5H2O) in 500 ml water
  • Add 10 ml acid twice daily (acid: 156 ml normal H2SO4 per litre solution)
• Apparatus: 5L glass beaker with cover, thermostat 140 mm above bottom, copper cooling tubing (outlet ≤ 30°C)
• Duration:
  • 8 days per cycle
  • For >8 days, refresh solution and repeat

Compliance Criteria (Clause 5.4)

• Response time of each detector must remain within limits specified in Table 1 or 2 after corrosion exposure.

Salt Droplet Test (Clause 1.3, Table C-1)

• Setup: Detector suspended 5–7.5 cm above water surface in a covered box
• Spray composition (g/l):
  | Sodium chloride | 23 |
  | Sodium sulphate | 8.9 |
  | Magnesium chloride | 9.8 |
  | Calcium chloride | 1.2 |
• Duration: 16 days, daily spray, temp 27 ± 2°C
• Post-test: Dry detector → measure response time with corroded lead

Key Points

• Maintain precise temperature and chemical concentrations.
• Response time after test must meet original specifications.
• Use Table 1 or 2 for detector-specific response time limits.

flowchart TD
    A[Prepare Corrosion Solution] --> B[Add Detector to Beaker]
    B --> C[Maintain 45±3°C with Heater & Thermostat]
    C --> D[Add Acid Twice Daily]
    D --> E{Test Duration}
    E -->|≤8 days| F[Measure Response Time]
    E -->|>8 days| G[Refresh Solution & Repeat]
    F --> H[Check Response Time Limits]

For detailed limits, refer to Tables 1 and 2 of IS 2175.

IS 2175 Shock Test Summary (Clause 5.5 & Appendix D)

Shock Test Procedure (Appendix D)

• Test Setup:
  • Timber block: 10 cm x 5 cm
  • Metal block mass: 3.5 kg
  • Drop height: 30 cm above timber surface (midpoint)
• Detector connected in normal operating circuit.
• Detector must NOT alarm due to shock.

Compliance Criteria (Clause 5.5)

• No alarm during shock.
• Post-test response time change ≤ 15% or 10 s, whichever is greater.

Vibration & Temperature Rise Reference (Tables 1 & 2)

• Number and rate of temperature rise for detectors during vibration/shock tests (refer to IS 2175 Tables 1 & 2 for specifics).

Salt Droplet Test (Clause 1.3)

• Detector suspended 5–7.5 cm above seawater.
• Spray daily with seawater (composition below) for 16 days.
• Temperature maintained at 27 ± 2°C.
• Post-test response time measured.

Mermaid Diagram: Shock Test Setup

graph TD
    A[Metal Block (3.5 kg)] -->|Drop 30 cm| B[Timber (10x5 cm)]
    B --> C[Detector mounted on timber]
    C --> D[Connected to normal circuit]
    D --> E[Check for alarm & response time]

Key Notes:

• Shock test ensures detector robustness against mechanical impact.
• Response time stability is critical for detector reliability.
• Salt droplet test simulates corrosive marine environment effects.

IS 2175: Supply Voltage Variation Test (Clause 5.8 & Appendix E)

• Purpose: Verify detector response stability under supply voltage fluctuations.
• Test Setup: Measure detector response time before and after voltage variation as per Appendix E.
• Acceptance Criteria:
  • The difference in response time must not exceed 15% or 10 seconds, whichever is greater.
  • No false alarms should occur during the test.
• Reference Tables:
  • Use Table 1 or Table 2 (depending on detector type) for temperature rise rate and numbering details.

Key Formula for Response Time Variation Limit

[ \Delta t \leq \max \left( 0.15 \times t_0, \ 10 \text{ seconds} \right) ]

Where:

• ( t_0 ) = response time before the test
• ( \Delta t ) = absolute difference between response times before and after voltage variation

Summary Table

flowchart TD
    A[Start Test] --> B[Measure Response Time Before]
    B --> C[Apply Supply Voltage Variation]
    C --> D[Measure Response Time After]
    D --> E{Check Response Time Variation}
    E -- ≤ 15% or 10s --> F[Pass Test]
    E -- > 15% or 10s --> G[Fail Test]
    F --> H[No False Alarm?]
    H -- Yes --> I[Test Complies]
    H -- No --> G

This ensures reliable detector performance despite voltage fluctuations per IS 2175.