Specification for Washers For Water Fittings For Fire Fighting Purposes

IS 937 Scope & Key Specifications Summary

• Scope: Covers dimensions, marking, and quality of washers used in fire-fighting hose couplings.

• Rounding Off: Final test/analysis values rounded per IS 2:1960, matching significant digits of specified values.

Washer Types & Dimensions (Clause 4.1)

Material & Workmanship (Clause 2.1)

• Rubber washers: Must conform to hardness per Type 3 of IS 5382:1985.
• Chemical resistance: No corrosion/damage after 30 min immersion in 20% H2SO4 or 5% NaOH.

Notes

• Nominal washer size corresponds to the nominal size of the fitting.
• Dimensions tolerances ensure interchangeability and proper sealing.

flowchart TD
    A[Nom

IS 937: Types of Washers — Key Specifications

Types of Washers (Clause 3.1)

• Type A Washer: See Fig. 1, Table 1
• Type B Washer: See Fig. 2, Table 2

Type A Washers (Clause 4.1 & Table 1)

• Tolerances:
  • Dia A: +0 / -1 mm
  • Dia B: +1 / -0 mm
  • Thickness C: ±0.5 mm

Type B Washers (Clause 4.1 & Table 2)

IS 937: Dimensions and Sizes of Washers for Water Fittings for Fire Fighting

Type A Washers (Table 1 & Fig. 1)

• Nominal size corresponds to fitting size.

Type B Washers (Table 2 & Fig. 2)

IS 937 - Key Specifications for Materials (Rubber Washers):

Rubber Requirements (Clause 2.1)

• Hardness: As per Type 3 of IS 5382:1985.
• Chemical Resistance: Must resist corrosion/damage after 30 min immersion in:
  • 20% Sulphuric acid, and
  • 5% Sodium hydroxide solution.
• Mechanical Properties: Hardness, tensile strength, elongation at break before and after ageing conforming to Type II B of IS 5382-1969.

Dimensional Tolerances for Washers (Clause 4.1)

Example Dimensions (Type B Washers)

Rounding Off (Clause 0.3)

• Final test values must be rounded as per IS 2-1960, keeping the same significant digits as specified.

Summary:
Rubber washers must meet IS 5382 hardness and chemical resistance criteria. Dimensional tolerances are tight, ensuring proper fit in pipe fittings. Use the above tables for selecting washer sizes based on nominal pipe size and application.

flowchart LR
    A[Rubber Washer] --> B[Meets IS 5382 Hardness & Strength]
    A --> C[Chemical Resistance Test]
    A --> D[Dimensional Tolerances per IS 937]
    D --> E[Dia A: +0/-1 mm]

IS 937: Workmanship and Finish for Washers

Key Specifications (Clause 5.1)

• Washers must be free from surface imperfections:
  • No blisters, porosity, grittiness, or foreign matter.
• Surface finish should be smooth.

Dimensions & Tolerances for Washers

Type A Washers (Table 1 & Fig. 1)

Type B Washers (Table 2 & Fig. 2)

Material Hardness (Clause 2.1)

• Rubber washers must conform to Type 3 of IS 5382:1985.
• Must be acid and alkali resistant:
  • No corrosion/damage

IS 937: Marking of Washers - Key Points

Clause 6.1 - Marking Requirements

Each washer shall be clearly and permanently marked with:

• Manufacturer's name or trade-mark
• Type of washer
• Year of manufacture

Clause 6.1.1 - ISI Certification Mark

• Washers may bear the ISI mark, indicating compliance with ISI quality control.
• Use of ISI mark is governed by the Indian Standards Institution (Certification Marks) Act.

Dimensions & Tolerances for Washers (Clause 4.1)

Nominal size corresponds to fitting size.

Rounding Off (Clause 0.3)

• Test results must be rounded off per IS: 2-1960, matching the significant figures of the specified value.

flowchart LR
    A[Washer] --> B{Marking}
    B --> C[Manufacturer's Name/Trade-mark]
    B --> D[Type of Washer]
    B --> E[Year of Manufacture]
    A --> F{Optional}
    F --> G[ISI Certification Mark

Inspection and Quality Control as per IS 937

Key Points:

• Rounding off results: Final test or analysis values must be rounded according to IS:2-1960, retaining the same number of significant figures as specified in IS 937 (Clause 0.3).

• ISI Certification Mark (Clause 6.1.1):

  • Washers may bear the ISI mark, indicating compliance with IS 937 under a strict inspection, testing, and quality control system supervised by ISI.
  • ISI-marked products undergo continuous conformity checks, assuring quality and reliability.

Quality Control System Highlights

• Inspection: Regular sampling and testing of washers for dimensional accuracy, material quality, and performance.
• Testing: Mechanical and hydraulic tests as per IS 937 requirements.
• Marking: Clear marking with ISI certification ensures traceability and quality assurance.

Summary Table: Rounding Off Rules (IS:2-1960)

Diagram: Quality Control Flow for ISI Marked Washers

flowchart TD
    A[Raw Material Inspection] --> B[Manufacturing Process Control]
    B --> C[Dimensional & Performance Testing]
    C --> D{Conforms to IS 937?}
    D -- Yes --> E[ISI Certification Marking]
    D -- No --> F[Rejection / Rework]
    E --> G[Continuous ISI Surveillance]

Note: For detailed testing procedures and dimensional tables, refer to IS 937 full text and related testing standards.

IS 937 (1981) does not explicitly provide detailed clauses on Packaging and Storage within the given context. However, general good practices based on standard engineering protocols and IS code principles are as follows:

Packaging and Storage Guidelines (General Engineering Practice)

• Packaging:

  • Use corrosion-resistant materials or coatings for packaging.
  • Ensure rubber washers conform to IS 5382:1985 Type 3 (hardness & acid/alkali resistance).
  • Protect components from moisture, dust, and mechanical damage.

• Storage:

  • Store in dry, well-ventilated areas.
  • Avoid direct contact with ground; use pallets or racks.
  • Maintain temperature and humidity to prevent corrosion and degradation.
  • For rubber components, avoid exposure to sunlight and ozone.

Key Specification from IS 937 (Clause 2.1):

• Rubber washers must resist corrosion after 30 minutes immersion in:
  • 20% Sulphuric acid
  • 5% Sodium hydroxide

Example: Rubber Washer Acid/Alkali Resistance Test

If you need detailed packaging dimensions or storage duration limits, please specify the product type or component.

IS 937: Specification for Washers for Water Fittings for Fire Fighting Purposes

Key Tables & Dimensions for Washers (Clause 4.1)

Type B Washers (Table 2):

Important Specifications

• Nominal washer size corresponds to the nominal size of the fitting.
• Dimensional tolerances are critical for proper fitting and sealing.
• Rounding off test or calculation results should follow IS:2-1960.

SI Units Reference (for engineering calculations)

Summary Diagram of Washer Dimensions

graph LR
A[Dia A] --> Washer[Washer]
B[Dia B] --> Washer
C[Thickness C] --> Washer

For detailed dimensional tables, tolerances, and usage remarks, refer to