Specification for Suction Hose Couplings For Fire Fighting Purposes

IS 902 Scope - Key Specifications & Tables

IS 902 specifies dimensions and tolerances for suction hose couplings used in firefighting.

Scope Highlights:

• Covers female coupling, male coupling, nut, locking ring, and washers.
• Couplings must resist corrosion: a 2.5 cm sample dipped in 20% H2SO4 or 5% NaOH for 30 mins shows no corrosion/damage.
• All dimensions in millimeters.
• Couplings conform to Figures 1 to 7 and Tables 1 to 3.

Key Tables Summary:

Example: Nominal Size 100 mm (from Tables 1 & 2)

Corrosion Test (Clause 2.5)

• Sample size: 2.5 cm cut piece
• Immersion: 20% sulphuric acid or 5% sodium hydroxide
• Duration: 30 minutes
• Result: No corrosion or damage allowed

For detailed dimensions and tolerances, refer to Figures 1-7 and Tables 1-3 in IS 902.

flowchart LR
    A[Coupling Components]
    A --> B(Female Coupling)
    A --> C(Male Coupling)
    A --> D(Nut for Female Coupling)
    A -->

IS 902: Referenced Indian Standards (Clause 2.1 & Annex A)

IS 902 relies on several Indian Standards as adjuncts, mainly covering materials and components used in fire fighting suction hose couplings:

Key Points:

• Materials for couplings: copper, copper alloys, aluminium, aluminium alloys.
• Avoid coupling aluminium alloys directly with copper alloys to prevent electrolytic corrosion.
• Aluminium alloy fittings preferably gravity die-cast.
• Wash aluminium alloy couplings with fresh water after sea/brackish water use.
• Use IS 937 for washers in couplings.
• Dimensions and tolerances follow IS 2102 and IS 4218 series.

Rounding Off:

• Follow IS 2:1960 for rounding off test results to maintain precision.

graph LR
A[IS 902 Couplings] --> B[Materials: Cu, Cu alloys, Al, Al alloys]
A --> C[Washers: IS 937]
A --> D[Threads & Dimensions: IS 4218, IS 2102]
A --> E[Sealing Rings: IS 5382]
A --> F[Hoses: IS 3549]

This ensures harmonized quality and compatibility in fire fighting suction

IS 902: Materials - Key Specifications & Tables

1. Material Requirements (Clause 3.1)

• Copper Alloys:

  • Sand castings: LTB 2 of IS 318:1981, Grade 3 of IS 304:1981
  • Die castings: Grade 3 of IS 292:1983
  • Hot forgings: Grade 1 of IS 291:1977

• Aluminium Alloys:

  • Castings conform to IS 617:1975 (IS Designation 4450 WP, 4225 WP, or 4600)
  • Only die castings allowed

2. Corrosion Resistance (Clause 2.5)

• A 2.5 cm sample dipped in 20% sulphuric acid / 5% sodium hydroxide for 30 min must show no corrosion or damage.

3. Dimensional Tolerances

• All dimensions in millimeters with specified tolerances (±0.4, ±0.8, etc.) for components like:
  • Tail Piece for Female Coupling
  • Male Coupling
  • Nut for Female Coupling
  • Locking Ring

4. Example Dimension Table (Tail Piece for Female Coupling)

Summary

• Use copper and aluminium alloys as per IS 291, 292, 304, 318, and 617 standards.
• Maintain strict dimensional tolerances for couplings and nuts.
• Ensure chemical resistance by acid/alkali

IS 902: Shape and Dimensions for Suction Hose Couplings

Key Specifications:

• Material: Aluminium alloys per IS 617 (Designations 4450 WP, 4225 WP, 4600), die cast only.
• Corrosion Test: 2.5 cm sample dipped in 20% H2SO4/5% NaOH for 30 min → no corrosion.
• Units: All dimensions in millimeters (mm).

1. Dimensions of Tail Piece for Female Coupling & Locking Ring (Table 1)

2. Dimensions of Male Coupling & Nut for Female Coupling (Table 2)

| Nominal Size | Male Coupling Dia-E (±0.4) | Dia-F (±0.8) | Dia-G (±0.8) | Dia-S1 (+0.40/-0.00) | Dia-M (±0.8) | P1 (±0.8) | Dia-R (±0.8) | Thickness (Min ±0.8) | Nut Dia-K (+0.40/-0.00) | Dia-N (±1) | P

IS 902: Construction and Workmanship - Key Points

1. Tolerances on Machined Dimensions

• As per Clause 6.1, tolerances must conform to IS 2102 (Part 1): 1980 — covers general tolerances for dimensions, form, and position.

2. Workmanship and Finish

• Corrosion resistance test: A 2.5 cm sample dipped in 20% H₂SO₄ / 5% NaOH for 30 min must show no corrosion/damage (Clause 2.5).
• Feather edges and smooth finishes are mandatory for all machined parts.

3. Dimensional Specifications

• Couplings and related components must follow dimensions and tolerances in Tables 1 & 2 (Clause 4.1):

• Refer to Figures 1-7 for shape and assembly details.

4. Referenced Standards

• IS 2102 (Part 1): General tolerances
• IS 4218 (Part 1-6): ISO metric screw threads
• IS 5382: Rubber sealing rings
• IS 291, 292, 304, 318, 581, 617: Material specifications for brass, bronze, aluminium, etc.

Summary Diagram: Workmanship Flow

flowchart TD
    A[Raw Material] --> B[Machining with IS 2102 Tolerances]
    B --> C[Surface Finish & Feather Edges]
    C --> D[Corrosion Test (

IS 902: Key Tolerances and Specifications Summary

1. Tolerances on Machined Dimensions

• As per Clause 6.1, unless otherwise specified, tolerances conform to IS 2102 (Part 1): 1980.

2. Thread Tolerances (Clause 4.1 & 5.2, Table 3)

3. Coupling Dimensions & Tolerances

• Tail Piece for Female Coupling (Table 1):

• Male Coupling & Nut for Female Coupling (Table 2):

IS 902: Workmanship and Finish - Key Specifications

1. Tolerances on Machined Dimensions

• As per Clause 6.1, tolerances shall conform to IS 2102 (Part 1): 1980 unless otherwise specified.

2. Corrosion Resistance

• Per Clause 2.5: A 2.5 cm sample dipped in 20% sulphuric acid / 5% sodium hydroxide for 30 minutes shall show no corrosion or damage.

3. Dimensional Tables (All dimensions in mm)

Table 1: Tail Piece for Female Coupling & Locking Ring (Clause 4.1)

Table 2: Male Coupling & Nut for Female Coupling (Clause 4.1)

| Nominal Size | Male Coupling Dia-E (±0.4) | Dia-F (±0.8) | Dia-G (±0.8) | Dia-S1 (+0.40/-0.00) | Nut Dia-K (+0.40/-0.00) | Thickness Min (±0.8) | Nut Dia

IS 902: Performance Requirements for Suction Hose Couplings

Key Performance Requirements (Clause 8 & related)

• Corrosion Resistance:
  A 2.5 cm cut piece dipped in 20% sulphuric acid / 5% sodium hydroxide solution for 30 minutes shall show no corrosion or damage.

• Dimensional Accuracy:
  Couplings must conform to dimensions and tolerances specified in Tables 1 & 2 and Figures 1 to 7.

  • Tolerances range from ±0.4 mm to ±1 mm depending on dimension.
  • Critical diameters like Dia-E, Dia-F, Dia-G, Dia-K, Dia-L, Dia-O, Dia-S for female coupling and Dia-E, Dia-F, Dia-G, Dia-S1, Dia-M, P1, Dia-R for male coupling and nut are specified.

• Surface Finish:
  All parts must be free from burrs and sharp edges.
  The waterway inside the coupling must have a smooth finish to ensure flow efficiency and prevent damage.

Summary Table Extract (Nominal Size 75 mm example):

Notes:

• Refer to Figures 1-7 for geometric shapes and assembly details.
• Ensure compliance with Annex A for related Indian Standards.

flowchart LR
    A[Material Sample] -->|Dip in acid/alkali| B{No corrosion?}
    B -->|Yes| C[Pass corrosion test]
    B -->|No| D[Fail corrosion test]
    C --> E[Check dimensions per Tables 1 & 2]
    E

IS 902: Marking - Key Specifications & References

Clause 2.1 - Marking

• Marking details are standardized; refer to Table 9 in Clause 2.1 for marking requirements.
• Marking must comply with referenced Indian Standards listed in Annex A, including:
  • IS 291, 292, 304, 318 (Brass and bronze ingots/castings)
  • IS 617 (Aluminium and aluminium alloy castings)
  • IS 2102 (Part 1): 1980 for general tolerances on machined dimensions
  • IS 4218 (ISO metric screw threads) for thread dimensions

Tolerances & Dimensions:

• Machined dimensions tolerances follow IS 2102 (Part 1): 1980.
• Dimensional tolerances for couplings and washers are detailed in Tables 1 & 2 (Clause 2.5), e.g., nominal coupling sizes 75, 100, 140 mm with specified diameters and thicknesses with ± tolerances.

Important Notes:

• Marking must be durable and legible.
• Materials like aluminium alloys must conform to IS 617 standards.
• Corrosion resistance test: 2.5 cm sample dipped in 20% H2SO4 / 5% NaOH for 30 min should show no damage.

Summary Table Example: Coupling Dimensions (from Table 1 & 2)

Reference for Machined Dimension Tolerances (IS 2102 Part 1:1980)

IS 902: List of Referenced Indian Standards (Clause 2.1, Annex A)

This clause lists essential Indian Standards referenced for materials and components used in fire fighting suction hose couplings:

Key Notes:

• Materials permitted: Copper, copper alloys, aluminium, aluminium alloys.
• Avoid coupling aluminium alloys directly with copper alloys to prevent electrolytic corrosion.
• Aluminium alloy fittings should preferably be gravity die-cast.
• Washers must conform to IS 937:1981.
• Tolerances and screw thread profiles follow IS 4218 and IS 2102.
• For dimensional rounding, use IS 2:1960 rules.

Summary Diagram of Material Compatibility

graph LR
A[Aluminium Alloys] -- Avoid direct contact --> B[Copper Alloys]
A -- Use fresh water wash --> Sea/Brackish Water
B -- Compatible with --> Copper Alloys

This prevents electrolytic action in couplings used in fire fighting hoses.