Specification for Gas cartridges for use in fire extinguishers

IS 4947 Scope - Key Specifications & Tables

• Material (Clause 4.1):
  Steel for cartridge body must meet:

  Property	Max/Min Value
  Carbon	0.3% max
  Silicon	0.35% max
  Sulphur	0.05% max
  Phosphorous	0.05% max
  Manganese	0.8% max
  Tensile Strength	≥ 35 kgf/mm²
  Yield Stress	≥ 25 kgf/mm²
  Elongation	≥ 20%

• Manufacture & Shape (Clause 4.4):

  • Made from seamless/welded steel tube or deep-drawn plate.
  • Thickness at ends ≥ thickness of parallel portion.
  • Cylindrical shell deviation ≤ 2% of nominal outside diameter.
  • Outlet threaded connection must be permanently attached and protected.

• Capacity & Filling (Clause 6):

  • Max filling ratio: 0.667 (mass CO₂ / mass water at 27°C).
  • Nominal capacity and filling tolerance (in grams):

  Capacity	Quantity (g)
  20	20 ± 5
  40	40 ± 3
  60	60 +10 / -0
  90	90 +10 / -0
  120	120 +10 / -0
  180	180 +10 / -0
  200	200 +10 / -0
  250	250 +10 / -0
  300	300 +10 / -0

• Gas Quality:
  CO₂ must be moisture-free, ≥99% pure per IS 15222.

Summary Diagram of Cartridge Structure

graph LR
A[Steel Tube or Plate] --> B[Body]
B --> C[Cylindrical Shell (±2% OD

IS 4947 Key References, Material Specs & Capacity

1. References (Table 2)

2. Material Specifications (Clause 4.1)

Chemical Composition (Max %):

• Carbon (C): 0.3
• Silicon (Si): 0.35
• Sulphur (S): 0.05
• Phosphorous (P): 0.05
• Manganese (Mn): 0.8

Physical Properties:

3. Capacity & Filling Ratio (Clause 6)

• Max Filling Ratio: 0.667 (mass CO2 / mass water at 27°C)
• Nominal Capacities & Quantity Tolerance:

4. Additional Notes

• CO2 gas must be **

IS 4947: General Requirements – Key Formulas, Tables & Specs

1. Material Specifications (Clause 4.1)

• Chemical Composition Limits:

• Physical Properties:

2. Manufacturing & Dimensional Requirements (Clause 4.4)

• Body made from seamless/welded steel tube or deep drawn flat plate.
• Minimum thickness at ends ≥ thickness of cylindrical portion.
• Cylindrical shell tolerance: max 2% deviation from nominal outside diameter.
• Outlet connection: permanently attached with thread protection cap.

3. Capacity & Filling (Clause 6)

• Maximum Filling Ratio:
  [ \text{Filling Ratio} = \frac{\text{Mass of CO}_2}{\text{Mass of water to fill container at 27°C}} = 0.667 ]

• Nominal Capacities & Filling Quantities:

4. Notes

• CO₂ gas must be moisture-free, 99% pure (

IS 4947: Material Specifications for Gas Cartridge Body

1. Chemical Composition (Clause 4.1a)

2. Physical Properties (Clause 4.1b)

3. Material Form & Fabrication (Clause 4.4)

• Body made from seamless/welded steel tube or deep-drawn flat plate.
• Minimum thickness of closed end ≥ thickness of parallel portion.
• Cylindrical shell deviation ≤ 2% of nominal outside diameter.
• Outlet connection permanently attached; protective cap to prevent thread damage.

4. Capacity and Filling Ratio (Clause 6)

• Max filling ratio: 0.667 (mass CO₂ / mass water at 27°C).
• Nominal capacities and tolerances given (e.g., 20g ±5g, 40g ±3g, etc.).

Notes:

• CO₂ must be moisture-free and 99% pure (IS 15222).
• Rounding off test results per IS 2:1960.

Summary Table: Steel Properties

flowchart TD
    A[Raw Material] --> B[Seamless/Welded Steel Tube or Deep Drawn Plate]
    B --> C[Form Body with Thickness ≥ Parallel Portion]
    C --> D[Attach Outlet Connection Permanently]
    D --> E[Protective Cap to Prevent Thread Damage]
    E --> F[Fill CO2 Gas (

IS 4947: Construction Key Specifications & Formulas

1. Material Properties (Clause 4.1)

2. Construction Details (Clause 4.4)

• Body: Made from seamless/welded steel tube or deep-drawn flat plate.
• Thickness: Minimum thickness of closed ends ≥ thickness of parallel portion.
• Shape: Cylindrical portion deviation ≤ 2% of nominal outside diameter.
• Outlet: Permanently attached after thread tightening; protective cap recommended to avoid thread damage.

3. Capacity & Filling Ratio (Clause 6)

• Max Filling Ratio: 0.667 (mass CO₂ / mass water at 27°C)
• Nominal Capacity & Quantity:

• CO₂ Quality: Moisture-free, 99% pure (IS 15222 compliant).

4. Rounding Rule

• Use IS 2:1960 for rounding

IS 4947: Capacity and Contents of Gas Cartridges

Key Specifications (Clause 6)

• Maximum filling ratio: 0.667
  (Mass of CO₂ charged / Mass of water to fill container at 27°C)

• Nominal Capacities and Allowed Quantities:

• Water capacity must be sufficient to hold the maximum permissible CO₂ quantity within the filling ratio.

• CO₂ purity: Minimum 99%, moisture-free, conforming to IS 15222.

Material Requirements (Clause 4.1)

• Steel Chemical Composition (Max %):

• Mechanical Properties:

Important Notes

• Protective caps must be screwed on outlet threads to prevent damage (Clause 4.4).
• Cylindrical shell thickness and shape tolerances are strictly controlled.
• Outlet connection is permanently attached post-thread tightening.

flowchart LR
    A[Water Capacity] --> B[Max Filling Ratio 0.667]
    B --> C[Mass of CO₂ charged]
    C --> D[Nominal Capacity Table]
    D --> E[Material & Mechanical Specs]

IS 4947: Performance Requirements Summary

1. Material Properties (Clause 4.1)

• Chemical Composition Limits:

• Mechanical Properties:

2. Filling Ratio & Capacity (Clause 6)

• Maximum Filling Ratio: 0.667 (mass CO₂ / mass water at 27°C)
• Nominal Capacities & Fill Quantities:

3. Dimensional & Manufacturing Requirements (Clause 4.4)

• Shell deviation from cylindrical form ≤ 2% of nominal outside diameter.
• Protective cap must be screwed on outlet to prevent thread damage.
• Outlet connection permanently attached after thread tightening.

Notes:

• CO₂ must be moisture-free and ≥ 99% pure per IS 15222.
• Thickness at closed end ≥ thickness of parallel portion.
• Welded parts designed for higher strength (see Clause 7.2).

flowchart LR
    A[Steel Body] --> B[Chemical Composition Limits]
    A --> C[Mechanical Properties]
    A --> D[Dimensional Tolerances]
    E[Gas Cartridge] --> F[Filling Ratio 

IS 4947 - Finish and Surface Treatment: Key Points

The standard revision introduced epoxy powder coating replacing lead-tin coating for surface protection.

Material Finish & Surface Treatment Specifications:

• Surface Treatment: Epoxy powder coating is the preferred finish for corrosion resistance.
• No detailed thickness or application method specified in IS 4947; refer to relevant paint/coating standards for epoxy powder coating application.

Steel Material Properties (Clause 4.1):

Notes:

• Epoxy powder coating provides durable corrosion resistance, better than traditional lead-tin coatings.
• For coating thickness and surface preparation, refer to IS 101 or IS 1477 for painting and powder coating standards.
• Rounding of test results must follow IS 2:1960 rules.

flowchart LR
    A[Steel Body] --> B[Surface Preparation]
    B --> C[Epoxy Powder Coating]
    C --> D[Corrosion Resistant Finish]

For detailed coating thickness and application, consult specialized coating standards or manufacturer datasheets.

IS 4947: Marking Specifications for Gas Cartridges

Marking Requirements (Clause 9.1)

Each cartridge must be clearly and permanently marked near its neck by embossing or punching with:

• Manufacturer's name or trademark
• Type of construction, sealing device, and capacity
• Gross mass of the charged cartridge
• Mass of the empty cartridge
• Year of manufacture

Standard Mark (Clause 9.2)

• The cartridge may bear the BIS Standard Mark under the Bureau of Indian Standards Act, 1986.
• Licensing conditions for using the Standard Mark are governed by BIS rules.

Capacity and Filling (Clause 6)

• Maximum filling ratio: 0.667 (mass of CO₂ to water mass at 27°C)
• CO₂ gas must be moisture-free, 99% pure, conforming to IS 15222.

Summary Diagram of Marking Location

graph LR
A[Neck of Cartridge] --> B[Embossed/Punched Markings]
B --> C[Manufacturer Name/Trademark]
B --> D[Type, Sealing Device, Capacity]
B --> E[Gross Mass]
B --> F[Empty Mass]
B --> G[Year of Manufacture]

Note: Marking must be durable, legible, and positioned to avoid damage during handling.

IS 4947: Sampling and Criteria for Conformity

Sampling Procedure (Clause 10.3 & Table 1)

• Sample size depends on lot size, selected randomly.
• For lots up to 300 items:

• For lots > 300, follow IS 2500 (Part 1) for sampling.

Criteria for Conformity (Clause 10.4)

• Samples are visually examined for:
  • Requirements in Clauses 3, 5, 6, 9 (e.g., hydraulic pressure, leakage, finish).
• The lot is accepted only if all samples pass these requirements.

Additional Notes

• Use of Standard Mark governed by BIS Act, 1986 (Clause 9.2.1).
• Sampling inspection plans refer to Attribute Sampling Plans indexed by AQL (Acceptable Quality Level) per IS 2500.

Summary Diagram of Sampling Process

flowchart TD
    A[Start: Lot Received] --> B{Lot Size ≤ 300?}
    B -- Yes --> C[Select sample size per Table 1]
    B -- No --> D[Follow IS 2500 (Part 1) sampling plan]
    C --> E[Randomly select samples]
    D --> E
    E --> F[Visual & Hydraulic Tests on samples]
    F --> G{All samples pass?}
    G -- Yes --> H[Lot Accepted]
    G -- No --> I[Lot Rejected]

This ensures quality control and conformity to IS 4947 standards.