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IS 2373 : 1981Water Meters (Bulk Type)

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ISO 4064-1 · OIML R 49-1 · EN 14154-1
CurrentSpecializedSpecificationBIMMEP · Sanitary Appliances and Water Fittings
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OverviewValues4InternationalTablesFAQ3Related

IS 2373:1981 is the Indian Standard (BIS) for water meters (bulk type). This standard specifies the requirements for materials, dimensions, construction, performance, and testing of bulk-type water meters (impeller type) used for measuring the bulk flow of cold potable water.

Water Meters (Bulk Type)

Overview

Status
Current
Usage level
Specialized
Domain
MEP — Sanitary Appliances and Water Fittings
Type
Specification
International equivalents
ISO 4064-1:2017 · International Organization for Standardization (ISO), InternationalOIML R 49-1:2013 · International Organization of Legal Metrology (OIML), InternationalEN 14154-1:2005+A2:2011 · European Committee for Standardization (CEN), EuropeAWWA C701-20 · American Water Works Association (AWWA), USA
Typically used with
IS 210IS 318IS 1538IS 2692
Also on InfraLens for IS 2373
4Key values2Tables3FAQs

BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.

Practical Notes
! Always install a strainer (dirt box) upstream of the bulk water meter to protect the impeller mechanism from debris.
! Maintain a straight pipe length of at least 10 times the diameter (10D) upstream and 5D downstream to ensure a uniform flow profile and accurate measurement.
! Ensure flanged connections are properly aligned and gaskets do not protrude into the pipe, as this can cause turbulence and affect meter accuracy.
Frequently referenced clauses
Cl. 4MaterialsCl. 5Manufacture and WorkmanshipCl. 7Performance RequirementsCl. 9Tests
Pulled from IS 2373:1981. Browse the full clause & table index below in Tables & Referenced Sections.
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International Equivalents

Similar International Standards
ISO 4064-1:2017International Organization for Standardization (ISO), International
HighCurrent
Water meters for cold potable water and hot water — Part 1: Metrological and technical requirements
Covers metrological and technical requirements for bulk water meters, but with modern performance classes.
OIML R 49-1:2013International Organization of Legal Metrology (OIML), International
HighCurrent
Water meters intended for the metering of cold potable water and hot water - Part 1: Metrological and technical requirements
Provides the internationally agreed-upon recommendations that form the basis for ISO 4064.
EN 14154-1:2005+A2:2011European Committee for Standardization (CEN), Europe
MediumCurrent
Water meters - Part 1: General requirements
European standard harmonized with older versions of ISO 4064, covering similar meter types.
AWWA C701-20American Water Works Association (AWWA), USA
MediumCurrent
Cold-Water Meters—Turbine Type, for Customer Service
Specifically covers turbine-type bulk meters, one of the main types included in IS 2373.
Key Differences
≠IS 2373 uses outdated metrological Classes (A and B), whereas modern standards like ISO 4064 use a flowrate ratio 'R' (Q3/Q1) which provides a much wider and more specific range of performance levels (e.g., R100 to R800+).
≠The flow rate nomenclature differs. IS 2373 uses 'minimum', 'transitional', and 'maximum' flow, while ISO 4064 uses a more defined system of Q1 (minimum), Q2 (transitional), Q3 (permanent), and Q4 (overload).
≠IS 2373:1981 is designed for purely mechanical meters. It contains no provisions for electronic registers, remote reading outputs, or communication protocols, which are extensively covered in current international standards.
≠ISO 4064 and OIML R 49 include detailed requirements for sensitivity to flow disturbances, specifying required straight pipe lengths upstream (U) and downstream (D) of the meter (e.g., U5/D3), which is not specified in IS 2373.
Key Similarities
≈All standards cover the same fundamental application: metering the volume of cold potable water in large, filled, closed conduits for billing or network management.
≈The basic accuracy requirement structure is consistent: a wider tolerance (±5%) is permitted in the lower flow region, and a tighter tolerance (±2%) is required for the main operational (upper) flow region.
≈Both IS 2373 and its international counterparts specify requirements for materials to be non-toxic and resistant to internal and external corrosion, ensuring durability and water safety.
≈Core constructional requirements such as the need for a clear, legible register, markings for direction of flow, and identification of the manufacturer and nominal size are common across all standards.
Parameter Comparison
ParameterIS ValueInternationalSource
Accuracy (Upper Flow Range)± 2% (from transitional to maximum flow)± 2% (from Q2 to Q4)ISO 4064-1:2017
Accuracy (Lower Flow Range)± 5% (from minimum to transitional flow)± 5% (from Q1 to Q2)ISO 4064-1:2017
Performance ClassificationMetrological Class A and Class BFlowrate Ratio 'R' (Q3/Q1), e.g., R100, R160, R250...OIML R 49-1:2013
Maximum Admissible Pressure1.0 MPa (10 kgf/cm²)Defined by pressure class, e.g., MAP 10 (1.0 MPa), MAP 16 (1.6 MPa)ISO 4064-1:2017
Maximum Water Temperature45 °CDefined by temperature class, e.g., T30 (30 °C), T50 (50 °C)ISO 4064-1:2017
Pressure Loss (Class B Equivalent)≤ 0.06 MPa (60 kPa) at maximum flowrateDefined by pressure loss class, e.g., Δp 63 (≤ 63 kPa at Q3)ISO 4064-1:2017
Body Hydrostatic Test Pressure1.5 MPa or 1.5 times working pressure1.6 times the Maximum Admissible Pressure (MAP)OIML R 49-1:2013
⚠ Verify details from original standards before use

Key Values4

Quick Reference Values
Nominal sizes covered50 mm to 300 mm
Hydrostatic test pressure1.6 MPa (16 kgf/cm²)
Maximum cold water temperature45°C
Maximum test duration for hydrostatic test1 minute

Tables & Referenced Sections

Key Tables
Table 1 - Nominal Sizes and Dimensions
Table 2 - Flow Rates and Accuracy Limits
Key Clauses
Clause 4 - Materials
Clause 5 - Manufacture and Workmanship
Clause 7 - Performance Requirements
Clause 9 - Tests

Related Resources on InfraLens

Cross-Referenced Codes
IS 210:2009Grey Iron Castings
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IS 318:2003Leaded Tin Bronze Ingots and Castings
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IS 1538:2018Hardened and Tempered Carbon Steel Wire for S...
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IS 2692:2018Ball Valves for Water Supply - Specification
→

Frequently Asked Questions3

What is the size range for bulk water meters covered by this IS code?+
It covers nominal sizes from 50 mm up to 300 mm.
What is the maximum water temperature for these meters?+
They are designed for cold water metering, typically suitable for water temperatures up to 45°C.
What hydrostatic pressure must the meter body withstand?+
The meter body must withstand a hydrostatic pressure of 1.6 MPa (approx. 16 bar) for 1 minute without leakage or sweating.

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