Specification for Portable Fire Extinguisher, Water Type (Gas Cartridge)

IS 940 - Scope Key Points (Clause 11.2 & Annexes)

The scope covers fire extinguishing agents focusing on environmental impact and reliability.

Key Specifications:

• Global Warming Potential (GWP) - 100 years (Annex D):

• Ozone Depleting Potential (ODP) (Annex B):

• Atmospheric Lifetime (Years) (Annex C):

Important Notes:

• Fire extinguishers must have high reliability throughout service (Annex E).
• Environmental impact (GWP, ODP, lifetime) guides agent selection.
• Sampling and conformity criteria ensure quality control.

flowchart LR
  A[Fire Extinguishing Agents] --> B[Environmental Impact]
  B --> C[GWP]
  B --> D[ODP]
  B --> E[Atmospheric Lifetime]
  A --> F[Reliability & Quality Control]

This scope ensures compliance with environmental protocols and performance standards.

Referenced Indian Standards in IS 940 (Portable Fire Extinguishers, Water Type - Gas Cartridge)

IS 940 refers to various Indian Standards (IS) for materials, components, and testing related to fire extinguishers. Key referenced standards include:

Important Formula (Clause 7.2 & 7.13) for Shell Thickness:

[ t = \frac{P \times D}{2 \times \sigma} ]

• (t) = thickness of shell (minimum 1.4 mm as per Clause 7.13)
• (P) = design pressure (in MPa)
• (D) = diameter of the shell (in mm)
• (\sigma) = allowable stress (in MPa)
• Note: In the formula, factor 300 is used instead of 360 (as per amendment).

BIS Certification Marking (Clause 12.2.1):

• Use of ISI mark is governed by BIS Act 1986.
• Manufacturer must obtain license from BIS.

Sampling and Conformity (Annex E):

• Details on sampling and criteria for conformity testing are provided in Annex E of IS 940.

Summary:

• IS 940 references

IS 940: General Requirements - Key Formulas & Specifications

1. Shell Thickness (Clause 7.13)

• Minimum shell thickness: 1.4 mm
• Calculated as per Clause 7.2 with substitution:
  [ \text{Use } 300 \text{ (instead of 360) in formula} ]

2. Sampling & Conformity (Clause 11.2.3, Annex E)

• High reliability required for fire extinguishers.
• Sampling criteria ensure performance consistency.
• Refer to Table 13 (Clause 11.2.3) for sampling plans.

3. Global Warming Potential (Annex D)

4. Amendments

• IS 6911 replaces IS 552 in Table 1 (Page 2).
• Use 300 instead of 360 in thickness formula (Page 1).

flowchart TD
    A[Design & Manufacture] --> B[Shell Thickness Calculation]
    B --> C{Thickness ≥ 1.4 mm?}
    C -- Yes --> D[Proceed]
    C -- No --> E[Increase Thickness]
    D --> F[Sampling & Testing]
    F --> G{Pass Criteria?}
    G -- Yes --> H[Certification]
    G -- No --> I[Rework/Reject]

This ensures fire extinguisher reliability and environmental compliance.

IS 940: Key Materials Specifications & Formulas

1. Material Specifications for Fire Extinguisher Components (Table 1, Clause 5)

2. Minimum Wall Thickness of Extinguisher Body (Clause 7.2)

• For Carbon Steel Bodies: [ t = \frac{P \times D}{2 \times \sigma} + 0.3 ]
• For Austenitic Stainless Steel Bodies: [ t = \frac{P \times D}{2 \times \sigma} + 0.3 ]

Where:

• ( t ) = Minimum thickness (mm)
• ( D ) = External diameter (mm)
• ( P ) = Design pressure (MPa)
• ( \sigma ) = Allowable stress (MPa)

Note: Clause 7.2 states the formula with a constant 600, which likely relates to allowable stress or design pressure in specific units.

3. Welding Requirements

• Body material must be weldable.
• Filler materials must be compatible with body steel to ensure sound welds.

Summary Diagram: Material Selection Flow

graph TD
A[Fire Ext

IS 940: Design and Construction Key Points

1. Material Specifications (Table 1, Clause 5)

2. Construction Requirements

• Syphon tube & strainer: Must be fitted inside the body; for squeeze grip type, fitted in the cap (Clause 7.4).
• Spring: Use spring steel wire as per IS 4454 (Part 1).
• Cap washer (O-ring): Rubber, acid and alkali resistant, hardness as per IS 5382 Type 3.

3. Sampling and Conformity

• High reliability is essential; sampling and conformity criteria detailed in Annex E.
• Design and manufacture must ensure performance throughout service life.

Summary Diagram: Fire Extinguisher Key Components & Materials

graph TD
    A[Body] -->|Mild Steel / Stainless Steel| B[IS 513 / IS 5522]
    C[Syphon Tube] -->|Brass / Stainless / Plastic| D[IS 407 / IS 6913 / IS 4985]
    E[Neck Ring] -->|Lead Tin Bronze / Steel / Stainless| F[IS 318 / IS 6913]
    G[Cap] -->|Aluminium / Brass / Tin Bronze| H[IS 11804 / IS 6912 / IS 318]
    I[Hose] -->|Rubber/Plastic| J[Min. bursting pressure 4 MN/m²]
    K[Gas Cartridge]

Welding Requirements as per IS 940 (Amend No.1 to 2003)

Welding Types & Relevant Standards (Clause 7.1.1)

• Oxy-acetylene welding: IS 1323
• Resistance welding:
  • Spot & Stitch welding (for fittings): IS 819
  • Seam welding: IS 1261
• Metal arc welding: IS 9595
• Electric arc welding: IS 2825

Material & Filler Compatibility (Clause 7.2)

• Body materials must be weldable.
• Filler materials must be compatible with body steel for sound welds.

Minimum Wall Thickness Calculation (Clause 7.2 & 7.13)

• For carbon steel bodies:

  [ t = \frac{p \times D}{300} + 0.3 \quad \text{(in mm)} ]

• For austenitic stainless steel bodies:

  [ t = \frac{p \times D}{600} + 0.3 \quad \text{(in mm)} ]

• Minimum shell thickness: Not less than 1.4 mm (Clause 7.13)

Where:

• ( t ) = minimum thickness, mm
• ( p ) = design pressure, MPa
• ( D ) = external diameter of the body, mm

Summary Table of Welding Standards

This ensures structural integrity and reliability of extinguisher bodies under pressure.

IS 940: Expansion Space & Pressure Calculations

Expansion Space (Clause 7.7, 1.5)

• Air space volume above the liquid level must be sufficient to ensure:
• When discharge nozzle is closed and extinguisher operated at 27 ± 5 ℃, internal pressure ≤ 1.5 MN/m² (15 bar).

Key Points:

• Expansion space prevents excessive pressure build-up due to liquid expansion.
• Volume of air space depends on liquid volume, temperature range, and gas laws.

Pressure Calculation (Ideal Gas Approximation):

[ P_2 = P_1 \times \frac{V_1}{V_2} \times \frac{T_2}{T_1} ]

Where:

• (P_1), (T_1), (V_1): Initial pressure, temperature, and volume of air space
• (P_2), (T_2), (V_2): Pressure, temperature, and volume after expansion
• Ensure (P_2 \leq 1.5 \text{ MN/m}^2)

Practical Specification:

• Provide an air space volume such that the gas expansion at max temperature does not exceed pressure limit.
• Usually, air space is about 10-15% of the total extinguisher volume.

Summary Table for Expansion Space:

flowchart LR
    A[Liquid Volume] --> B[Expansion due to Temp Rise]
    B --> C[Air Space Volume]
    C --> D[Pressure Increase]
    D --> E{Pressure ≤ 1.5 MN/m²?}
    E -- Yes --> F[Safe Design]
    E -- No --> G[Increase Air Space Volume]

Note: Always confirm with detailed manufacturer data and perform sample testing per Clause 1.2.6 and 10.3 for conformity.

IS 940: Surface Treatment and Plastic Lining Key Points

1. Surface Treatment Specifications (Clause 8.1)

• External & Internal Surfaces: Epoxy powder coated.
• Minimum Thickness: 0.050 mm (50 microns).
• Measurement: As per IS 3203.
• Alternative Internal Coating: Plastic/rubber lining with minimum thickness 0.5 mm.

2. Plastic Lining Tests (Clause 8.2)

• Adhesion Test (Type Test):

  • Pressure: 15 kgf/cm².
  • Duration: 120 ± 4 hours.
  • Temperature: 27 ± 5°C.
  • Acceptance: No cracking, separation, lifting, or bubbles.

• Continuity Test:

  • Fill extinguisher to 10 mm below lining top with 1% sodium chloride solution + hydrocarbon surfactant.
  • Surface tension < 40 mN/m.
  • Apply insulation resistance test: 500 ± 50 MΩ between metal body and electrode in solution.
  • Purpose: Check lining continuity (no leaks).

Summary Table

flowchart TD
    A[Steel Body] --> B[External Epoxy Powder Coating (≥0.05mm)]
    A --> C[Internal Plastic/Rubber Lining (≥0.5mm)]
    C --> D[Adhesion Test: 15 kgf/cm², 120h, 27°C]
    C --> E[Continuity Test: NaCl Solution + Insulation Resistance]

This ensures corrosion protection and integrity of fire extinguisher bodies as per IS

IS 940 - Marking and Labeling Key Points

Clause 12.1: Mandatory Markings on Extinguishers

Each fire extinguisher must be clearly and permanently marked with:

• Manufacturer's name or trade-mark
• Method of operation (prominent letters)
• The words "Water type (Gas cartridge)" (prominent letters)
• Size of gas cartridge used
• Liquid level to which the extinguisher is charged
• The phrase "Tested to a hydraulic pressure 3 MN/m² (30 kgf/cm²)"
• Year of manufacture

Clause 12.2: BIS Certification Mark

• The extinguisher may carry the Standard Mark as per BIS Act 1986.
• License for use of Standard Mark is governed by BIS rules.

Annex E: Sampling & Criteria for Conformity

• High reliability is mandated through strict design and manufacturing control.
• Sampling procedures and conformity criteria ensure performance consistency.

Summary Table: Marking Requirements

This ensures traceability, safety, and compliance with IS 940 standards.

IS 940: Testing and Performance Requirements - Key Points

1. Performance Test (Clause 1.2.6 & 10.3):

   • One sample from each lot must be tested for performance and expansion space.
   • The sample must pass all tests for the lot to conform.

2. Sampling and Criteria for Conformity (Clause 11.2.3 & Annex E):

   • Sampling plans ensure high reliability due to the critical nature of fire extinguishers.
   • Annex E details sampling procedures and acceptance criteria.

3. Global Warming Potential (GWP) of Substances (Annex D):

   Substance	GWP (100-year CO2 eq.)
   Halon 1301	5600
   FM 200	3300
   FE 13 n	12100
   FE 36	8000
   NAFS III	1450
   CF 31	<5

   • Substances with lower GWP are preferred environmentally.

4. Standards Referenced (Annex A):

   • Includes IS for materials, corrosion protection, gas cartridges, and more, ensuring quality and safety.

Summary Table: Sampling & Performance Testing

Mermaid Diagram: Sampling & Testing Flow

flowchart TD
    A[Start: Lot Production] --> B[Select 1 Sample]
    B --> C{Performance Test}
    C -- Pass --> D{Expansion Space Test}
    C -- Fail --> E[Reject Lot]
    D -- Pass --> F[Lot Conforms]
    D -- Fail --> E

Note: For detailed sampling tables and test procedures, refer to Annex E and Clause 10.3 of IS 940.

IS 940: Environmental and Safety Requirements Summary

Key Specifications:

1. Ozone Depleting Substances (ODS) - Annex B (Clause 11.2.1)

• Note: ODP values are relative to CFC-11 = 1.0.

2. Global Warming Potential (GWP) - Annex D (Clause 11.2.3)

3. Atmospheric Lifetime (Years) - Annex C (Clause 11.2.2)

Important Notes:

• Fire extinguishing agents must balance environmental impact (low ODP & GWP) and performance reliability.
• Use inert gases (Argon, Argonite, Inergen) for minimal environmental harm.
• High GWP agents like FE 13 n and Halon 1301 are discouraged due to global warming and ozone

IS 940: Certification and Marking Key Points

Clause 12.2 BIS Certification Marking:

• Fire extinguishers may bear the BIS Standard Mark.
• Use of the Standard Mark is regulated under the Bureau of Indian Standards Act, 1986.
• Manufacturers must obtain a license from BIS to use the Standard Mark.
• Details and conditions for licensing are available from BIS.

Sampling and Conformity (Clause 13, Annex E):

• Fire extinguishers require high reliability, ensured by strict design and manufacturing control.
• Sampling plans and conformity criteria are specified in Annex E.
• In absence of manufacturer’s certificate, type tests are conducted on individual components.

Referenced IS Standards (Annex A):

• Includes standards for materials, corrosion protection, gas cartridges, and components related to fire extinguishers.
• Examples:
  • IS 5: Colours for paints/enamels
  • IS 4947: Gas cartridges for extinguishers
  • IS 2190: Installation and maintenance of extinguishers

Summary Table: BIS Certification Marking

Additional Notes:

• BIS certification ensures product quality and compliance.
• Marking facilitates consumer confidence and regulatory acceptance.
• Sampling ensures batch conformity to standards.

flowchart TD
    A[Manufacturer] --> B{Apply for BIS License}
    B -->|Approved| C[Use BIS Standard Mark]
    B -->|Rejected| D[No Marking Allowed]
    C --> E[Manufacture with Quality Control]
    E --> F[Sampling & Testing (Annex E)]
    F --> G{Conforms?}
    G -->|Yes| H[Product Released]
    G -->|No| I[Rejection/Rectification]

For detailed licensing conditions, contact BIS regional offices or visit the BIS website.

IS 940: Sampling and Criteria for Conformity

Sampling Plan (Clause E-1.2.2 & E-1.2.3)

• Samples are taken randomly from the lot.
• Visual examination per Clauses 3 to 9 (except 7.7).
• Hydraulic pressure test and corrosion test per Clauses 10.1 and 10.4.

Criteria for Conformity (Annex E)

• Fire extinguishers must demonstrate high reliability.
• Failure risk is minimized by strict design and manufacturing controls.
• Testing ensures compliance with performance and safety requirements.

Notes

• Refer to Annex E for detailed conformity criteria.
• Sampling ensures quality control and reliability of fire extinguishers.

flowchart TD
    A[Lot of Fire Extinguishers] --> B[Random Sampling]
    B --> C{Sample Size}
    C -->|Up to 25| D[3 Samples]
    C -->|26 to 50| E[5 Samples]
    C -->|51 to 100| F[8 Samples]
    C -->|101 to 200| G[8% Samples]
    D & E & F & G --> H[Visual + Hydraulic + Corrosion Tests]
    H --> I{Pass Criteria Met?}
    I -->|Yes| J[Lot Accepted]
    I -->|No| K[Lot Rejected]

This sampling plan ensures statistically valid quality control aligned with IS 940 standards.

IS 940: List of Referenced Indian Standards (Annex A)

This standard references multiple IS codes critical for materials, components, and testing of portable water-type fire extinguishers (gas cartridge). Key referenced standards include:

Important Formula (Clause 7.13) for Shell Thickness

• Minimum shell thickness, t ≥ 1.4 mm.

• Thickness calculation per Clause 7.2 with updated factor:

  [ t = \frac{P \times d}{2 \times \sigma \times 300} ]

  where:

  • (P) = design pressure
  • (d) = diameter of the shell
  • (\sigma) = allowable stress of material
  • 300 = revised factor replacing 360

Notes:

• Refer to IS 2190 for maintenance and installation.
• BIS certification and marking governed by BIS Act 1986.
• Sampling and conformity details in Annex E.
• Use latest editions of referenced standards for compliance.

flowchart LR
    A[IS 940] --> B[Materials Standards]
    A --> C[Testing & Maintenance]
    B --> IS5[IS 5:1994 Paints]
    B --> IS318[IS 318:1981 Bronze]
    B --> IS407[IS 407:1981 Brass Tubes]
    C --> IS2190[IS 2190: Fire Extinguish

IS 940: Key Data on Ozone Depleting Substances (ODS) and Related Environmental Metrics

1. List of Ozone Depleting Substances (ODS) - Annex B (Clause 11.2.1)

• Note: ODP values are relative to CFC-11 (assigned 1.0).

2. Atmospheric Lifetime of Gas-Based Agents - Annex C (Clause 11.2.2)

3. Global Warming Potential (GWP) - Annex D (Clause 11.2.3)

4. Code Compliance

• Fire extinguishers must not contain any ODS as per Clause 11.2.1.
• Selection of agents should