Gaseous Fire Extinguishing Systems - IG 01 Extinguishing Systems

IS 15497: Scope - Key Formulas, Tables & Specifications

1. Safety Limits for IG 01 Agent (Table 6, Clause 5.4)

• NOAEL: No Observed Adverse Effect Level
• LOAEL: Lowest Observed Adverse Effect Level

2. Human Exposure to IG 01 (Table 7, Clause 5.5)

3. Allowable Strength of Enclosure (Table 8, Clause 6.3)

4. Free Venting Area Calculation (Clause 6.3)

[ A = 5 \times 10^{-4} \times Q \times P^{0.5} ]

• A = Free venting area (m²)
• Q = IG 01 discharge rate (m³/min)
• P = Allowable enclosure strength (kPa) (see Table 8)
• For exceptionally tight enclosures, (P) is trebled.

5. Total Flooding Quantity of IG 01 (Table 9, Clause

IS 15497: General Information Key Formulas, Tables & Specs

1. Enclosure Strength & Venting (Clause 6.3)

• Allowable Load on Enclosure (Table 8):

• Venting Area Formula: [ A = (5 \times 10^{-4}) \times Q \times P^{-0.5} ] Where:
• (A) = free venting area (m²)
• (Q) = IG 01 discharge rate (m³/min)
• (P) = allowable enclosure strength (kPa)

For exceptionally tight enclosures, multiply (P) by 3.

2. Safety Limits for IG 01 (Table 6, Clause 5.4)

3. Human Exposure Limits (Table 7, Clause 5.5)

4. IG 01 Physical Properties (Table 2, Clause 4.4)

IS 15497: Gas Characteristics and Properties for IG 01 (Argon)

1. Physical Properties (Clause 4.4, Table 2)

2. Specification for IG 01 (Clause 4.2, Table 1)

• Purity: ≥ 99.9% by volume
• Moisture: ≤ 50 x 10⁻⁶ by mass
• Suspended matter: None visible

3. Toxicological Information (Clause 4.5, Table 3)

Note: NOAEL and LOAEL correspond to oxygen levels of 12% and 10%, respectively, indicating safe exposure limits.

Summary Diagram: IG 01 Gas Properties

graph TD
A[Molecular Mass: 39.9] --> B[Boiling Point: -185.9ºC]
B --> C[Critical Temperature: -122.3ºC]
C --> D[Critical Pressure: 4.9 MPa]
D --> E[Purity: ≥ 99.9%]
E --> F[NOAEL: 43% volume]
F --> G[LOAEL: 52% volume]

This concise data aids in design, safety, and handling of IG 01 gas per IS 15497.

Safety of Personnel - IS 15497 Key Points

1. Safety Limits for IG 01 Agent (Table 6, Clause 5.4)

2. Human Exposure Limits (Table 7, Clause 5.5)

3. Minimum Safety Precautions (Table 5, Clause 5.4)

4. Enclosure Strength & Venting (Clause 6.3, Table 8)

Venting Area Formula:

[ A = 5 \times 10^{-4} \times Q \times P^{-0.5} ]

• (A) = free venting area (m

IS 15497: Enclosure Strength and Venting Facilities (Clause 6.3)

Key Formula for Free Venting Area (A):

[ \boxed{ A = (5 \times 10^{-4}) \times Q \times P^{-0.5} } ]

• A = Free venting area (m²)
• Q = IG-01 agent discharge rate (m³/min)
• P = Allowable strength of the enclosure (kPa)

Allowable Strength of Enclosure (Table 8):

For exceptionally tight enclosures, multiply P by 3.

Notes:

• Venting area ensures pressure relief during IG-01 discharge.
• Design enclosure strength depends on construction type.
• Safety limits and exposure times are critical for human safety (see Tables 5-7).
• Venting facilities must comply with these to prevent enclosure rupture.

flowchart LR
    Q[IG-01 Discharge Rate Q (m³/min)] --> A[Calculate Venting Area A]
    P[Allowable Enclosure Strength P (kPa)] --> A
    A --> VentingArea[Free Venting Area (m²)]
    VentingArea --> Safety[Ensure safe pressure relief]

This ensures safe design of enclosures for IG-01 fire suppression systems per IS 15497.

Key Formulas & Tables for Extinguishing Agent Supply (IS 15497)

1. Total Flooding Quantity (IG 01 Agent)

From Clause 7.2(b) and 2.303:

[ \boxed{ M = 2.303 \times V \times \log_{10} \frac{100}{100 - C} \times S \times V_s } ]

• M = Total agent quantity (kg)
• V = Net hazard volume (m³)
• C = Design concentration (% by volume)
• S = (K_1 + K_2 \times T) (temperature correction)
• V_s = Specific vapor volume at 21°C (m³/kg)

Constants for IG 01:

• (K_1 = 0.79968)
• (K_2 = 0.00293)
• (T) = Minimum enclosure temperature (°C)

2. Design Concentration & Exposure Limits (Table 6 & 7)

3. Discharge Duration & Atmospheric Correction (Clause 7.3.3, Table 10)

• Discharge time:

  • 95% agent mass discharged within 60 s at 27°C.
  • Minimum concentration (34%) achieved within 1 min; actual within 2 min.

• Atmospheric Correction Factor adjusts agent quantity for altitude:

IS 15497: Concentration Requirements for IG 01 Fire Extinguishing Agent

Key Specifications & Formulas

1. Design Concentration (Clause 8.1 & Table 8.1)

• Minimum design concentration for Class A surface fires (including electrical/electronic hazards) varies with temperature.
• Table 8.1 provides mass of IG 01 agent (kg/m³) per volume of hazard at different temperatures and volume percentages.

2. Total Flooding Quantity (Clause 7.2)

• Required IG 01 quantity to achieve design concentration:

[ M_{th} = V_{Max} \times C_1 ]

Where:

• (M_{th}) = theoretical IG 01 volume (m³)
• (V_{Max}) = max net enclosure volume (m³)
• (C_1) = injected concentration (volume %)

3. Number of Containers (Clause 7.3.2 b)

[ N = \frac{M_{th}}{M_c} ]

• (N) = number of containers (rounded)
• (M_c) = IG 01 quantity per container (m³)

4. Actual Quantity & Concentration (Clause 7.3.2 c,d)

[ M_A = N \times M_c ]

[ C_{AI} = \frac{M_A}{V_{Max}} ]

• (M_A) = actual IG 01 stored
• (C_{AI}) = actual injected concentration (volume %)

Summary Table Extract (Example at 20°C)

Notes:

• Oxygen concentration limits per Clause 5.3 must be maintained.
• Use standard cylinders for logistics.
• Adjustments per Clause 7.1(d) may apply.

flowchart TD
    A[Calculate Theoretical IG 01 Quantity] --> B[Determine Number of Containers]
   

IS 15497 — Rate of Application for IG-01 (MA) Inert Gas Systems

Key Points from Clauses:

• Design Application Rate (7.3.2):
  Based on quantity of IG-01 required for desired concentration (Clause 8.1) and time to achieve it (Clause 7.2).
  Oxygen concentration must comply with limits in Clause 5.3.

• Discharge Time (7.3.3 & 12.1):

  • 95% of agent mass discharged within 60 seconds at 27°C.
  • Minimum theoretical concentration (34% vol) achieved within 1 min; actual concentration within 2 min.
  • Hydraulic calculations must predict pipe sizes, nozzle pressure, flow rate, and discharge time.

• Atmospheric Correction Factors (Table 10, Clause 7.3.3):

Formula for Adjusted Agent Quantity:

[ Q_{adjusted} = Q_{design} \times \text{Atmospheric Correction Factor} ]

Where:

• (Q_{design}) = Agent quantity at sea level conditions
• Correction factor accounts for altitude effects on pressure and discharge

Summary:

• Achieve minimum 34% vol concentration within 1 minute.
• Discharge 95% agent mass within 60 seconds.
• Use hydraulic

IS 15497: Key Formulas, Tables & Specs for IG 01 Storage Containers

1. Storage Containers (Clause 10)

• Seamless cylinders per IS 7285, certified by Chief Controller of Explosives.
• Must have reliable pressure indication and pressure-temperature chart attached.
• Follow stricter authority requirements if applicable.

2. Agent Quantity & Containers (Clause 7.3.2)

• Vmax: max enclosure volume (m³)
• C1: design/injected concentration (%)
• Mc: IG 01 quantity per container (m³)
• N: number of containers

3. Retention Time (Clause 9.3)

• ≥ 80% of design concentration must remain 10 minutes after discharge.

4. Safety Limits (Table 6, Clause 5.4)

5. Human Exposure (Table 7, Clause 5.5)

6. Enclosure Strength (Table 8, Clause 6.3)

| Type | Typical Structure | Allowable Load

IS 15497: Distribution System Key Points & Tables

1. Hydrostatic Test (Clause 11)

• Distribution piping must be tested at 1.5 × max developed storage pressure at 55°C.
• System purged to remove moisture and verified for free passage.

2. Enclosure Integrity

• Must comply with IS 15493 enclosure integrity test.

3. Discharge Time (Clause 7.3.3)

• 95% agent mass discharged within 60 seconds at 27°C.
• Minimum theoretical concentration (34% vol) achieved within 1 min, actual with safety factor within 2 min.
• Extended discharge allowed at reduced rate after initial discharge.

4. Retention Time (Clause 9.3)

• At least 80% of design concentration retained 10 minutes after discharge.

5. Atmospheric Correction Factors (Table 10)

(Use correction factor to adjust agent quantity for altitude)

6. Safety Limits for IG 01 (Table 6)

7. Human Exposure Limits (Table 7)

• Concentrations >62%: No exposure permitted.
• 43–52%: Exposure ≤3 min in normally occupied spaces.

8. Allowable Load on Enclosure (Table 8)

Hydraulics of the System (IS 15497 Key Points)

1. Hydraulic Calculations (Clause 12.1):

• Use approved methods to predict:
  • Pipe sizes
  • Nozzle pressure
  • Agent flow rate
  • Discharge per nozzle
  • Discharge time

2. Pipe Sizing (Clause 11.3):

• Avoid too small bore (excess pressure loss) or too large bore (low velocity, pressure drop).
• Use computer flow calculation programs for accuracy.

3. Discharge Time & Agent Flow (Clause 7.3.3):

• Minimum theoretical injected concentration: 34% by volume within 1 min.
• Actual concentration (with safety factor) within 2 min.
• 95% of agent discharged within 60 s.
• Extended discharge possible at reduced rate after initial discharge.

4. Atmospheric Correction Factors (Table 10, Clause 7.3.3):

Use correction factor to adjust agent discharge time and concentration for altitude.

Summary Formula for Discharge Time Adjustment:

[ \text{Adjusted Discharge Time} = \frac{\text{Standard Discharge Time}}{\text{Atmospheric Correction Factor}} ]

Important Notes:

• Ensure minimum inerting concentration before flammable vapors reach flammable range (for explosion prevention).
• Consult authorities if container location causes extended transit time.

flowchart TD
    A[Start: System Design] --> B[Calculate Required Agent Concentration]
    B --> C[Apply Atmospheric Correction Factor]
    C --> D[Determine Pipe Size & Nozzle Pressure]
    D --> E[Calculate Agent Flow Rate & Discharge Time]
    E --> F{Discharge

IS 15497: Commissioning & Acceptance Testing Key Points

1. Commissioning Certification (Clause 13.2)

• Installation agency issues a test certificate after commissioning completion.

2. Accuracy Limits (Clause 12.2)

3. Acceptance Criteria (Clause 13.1)

• Commission per IS 15493 Clause 9.
• Full-scale discharge test generally not recommended.
• If required, follow Clause 14.
• Otherwise, follow partial discharge test with monitoring.

4. Reporting Requirements (Clause 14.3)

• Identification: installer, designer, enclosure, temp.
• Gas concentrations (O2, CO2) before discharge.
• Date/time, discharge time.
• Concentration at 2 & 10 min post-discharge.
• System deficiencies.
• Reference to IS 15493 test method.

Summary Table: Key Acceptance Test Parameters

flowchart TD
    A[Commissioning Completion] --> B[Installation Agency Issues Test Certificate]
    B --> C{Acceptance Criteria}
    C -->|Full-scale test required| D[Conduct Full-Scale Test (Clause 14)]
    C -->|Not required| E[Partial Test & Monitoring]
    D --> F[Report Test Results]
    E --> F
    F --> G[System Acceptance]

Note: Refer IS 15493 for detailed commissioning procedures and test methods.

IS 15497: IG 01 Full Scale Discharge Test Procedure (Clause 14 & related)

Key Specifications & Acceptance Criteria

• Full-scale discharge test is not normally recommended; only if authorities insist.
• The system must achieve:
  • Minimum theoretical injected concentration: 34% by volume within 1 min.
  • Actual injected concentration: (minimum + safety factor) within 2 min.
  • 95% of agent mass discharged: within 60 seconds at 27°C.
• Discharge time must ensure flame extinguishment or explosion prevention.

Important Tables

Key Formula for Discharge Time Adjustment:

[ t_{corrected} = t_{base} \times \text{Atmospheric Correction Factor} ]

Where:

• (t_{base}) = discharge time at sea level,
• Correction factor from Table 10 depending on altitude.

IS 15497: Recommissioning Key Points

1. Recommissioning (Clause 14.2)

• Restore all systems to fully operational status after maintenance or modifications.
• Ensure functionality and safety compliance as per original commissioning.

2. Commissioning Certification (Clause 13.2)

• Installation agency must issue a test certificate after commissioning.
• Certificate confirms system meets design and safety parameters.

3. Safety Limits for IG-01 Agent (Table 6, Clause 5.4)

4. Human Exposure Limits (Table 7, Clause 5.5)

5. Allowable Enclosure Strength (Table 8, Clause 6.3)

6. Extinguishing Agent Supply Accuracy (Clause 12.2)

• Agent weight discharge: -5% to +10% accuracy.
• Discharge time: ±5 seconds accuracy.
• Nozzle pressures: Must remain within specified minimum and maximum for uniform agent distribution.

flowchart TD
    A[System Maintenance] --> B[Recommissioning]
    B --> C[Restore Full Operation]
    C --> D[Functional Tests]
    D