Section 3.36. Water Meters

# 

# A. Application

**A.1.** - This code applies to devices used for the measurement of
water; generally applicable to, but not limited to, utilities type
meters installed in residences or business establishments and meters
installed in batching systems.

(Amended 2002)

**A.2.** - This code does not apply to:

> \(a\) water meters mounted on vehicle tanks (for which see Sec. 3.31;
> Code for Vehicle-Tank Meters) or
>
> \(b\) mass flow meters (see Sec. 3.37. Code for Mass Flow Meters).

(Added 1994)

**A.3.** - See also Sec. 1.10; General Code requirements.

# S. Specifications

**S.1. Design of Indicating and Recording Elements and of Recorded
Representations.**

> **S.1.1. Primary Elements.**
>
> **S.1.1.1. General.** - A water meter shall be equipped with a primary
> indicating element and may also be equipped with a primary recording
> element. Such elements shall be visible at the point of measurement or
> be stored in non-volatile and nonresettable memory. The display may be
> remotely located provided it is readily accessible to the customer.

(Amended 2002)

> **S.1.1.2. Units.** - A water meter shall indicate and record, if the
> device is equipped to record, its deliveries in terms of liters,
> gallons or cubic feet or binary or decimal subdivisions thereof except
> batch plant meters, which shall indicate deliveries in terms of
> liters, gallons or decimal subdivisions of the liter or gallon only.
>
> **S.1.1.3. Value of Smallest Unit.** - The value of the smallest unit
> of indicated delivery and recorded delivery, if the device is equipped
> to record, shall not exceed the equivalent of:
>
> \(a\) 50 L (10 gal) on utility type meters,
>
> \(b\) 0.2 L (^1^/10 gal) on batching meters delivering less than
> 375 L/min (100 gal/min), or
>
> \(c\) 5 L (1 gal) on batching meters delivering 375 L/min
> (100 gal/min) or more.
>
> **S.1.1.4. Advancement of Indicating and Recording Elements.** -
> Primary indicating and record­ing elements shall be susceptible to
> advance­ment only by the mechanical operation of the device.
>
> **S.1.1.5. Return to Zero.** - If the meter is so designed that the
> primary indicating elements are readily return­able to a definite zero
> indication, means shall be provided to prevent the return of these
> elements beyond their correct zero position.
>
> **S.1.2. Graduations.**
>
> **S.1.2.1. Length.** - Graduations shall be so varied in length that
> they may be conveniently read.
>
> **S.1.2.2. Width.** - In any series of graduations, the width of a
> graduation shall in no case be greater than the width of the minimum
> clear interval between graduations, and the width of main graduations
> shall be not more than 50 % greater than the width of subordinate
> graduations. Graduations shall in no case be less than 0.2 mm
> (0.008 in) in width.
>
> **S.1.2.3. Clear Interval Between Graduations.** - The clear interval
> shall not be less than 1.0 mm (0.04 in). If the graduations are not
> parallel, the measurement shall be made:
>
> \(a\) along the line of relative movement between the graduations at
> the end of the indicator, or
>
> \(b\) if the indicator is continuous, at the point of widest
> separation of the graduations.
>
> **S.1.3. Indicators.**
>
> **S.1.3.1. Symmetry.** - The index of an indicator shall be
> symmetrical with respect to the graduations, at least throughout that
> portion of its length associated with the graduations.
>
> **S.1.3.2. Length.** - The index of an indicator shall reach to the
> finest graduations with which it is used, the width of the minimum
> clear interval between graduations, and the width of main graduations
> shall be not more than 50 % greater than the width of subordinate
> graduations. Graduations shall in no case be less than 0.2 mm
> (0.008 in) in width.
>
> **S.1.3.3. Width.** - The width of the index of an indicator in
> relation to the series of graduations with which it is used shall not
> be greater than:
>
> \(a\) *the width of the narrowest graduation\** , and
>
> *\[\*Nonretroactive as of January 1, 2002\]*
>
> (Amended 2001)
>
> \(b\) the width of the minimum clear interval between graduations.

When the index of an indicator extends along the entire length of a
gradua­tion, that portion of the index of the indicator that may be
brought into coincidence with the graduation shall be of the same width
throughout the length of the index that coincides with the graduation.

> **S.1.3.4. Clearance.** - The clearance between the index of an
> indicator and the graduations shall in no case be more than 1.5 mm
> (0.06 in).
>
> **S.1.3.5. Parallax.** - Parallax effects shall be reduced to the
> practicable minimum.

**S.2. Design of Measuring Elements.**

> **S.2.1. Provision for Sealing.** - Adequate provision shall be made
> for applying security seals in such a manner that no adjustment or
> interchange may be made of:
>
> \(a\) any measurement elements, and
>
> \(b\) any adjustable element for controlling delivery rate when such
> rate tends to affect the accuracy of deliveries.
>
> The adjusting mechanism shall be readily accessible for purposes of
> affixing a security seal.
>
> **S.2.2. Batching Meters Only.**
>
> **S.2.2.1. Air Elimination.** - Batching meters shall be equipped with
> an effective air eliminator.
>
> **S.2.2.2. Directional Flow Valves.** - Valves intended to prevent
> reversal of flow shall be automatic in operation.
>
> **S.2.3. Multi-Jet Meter Identification.** - Multi-Jet water meters
> shall be clearly and permanently marked as such on the device or
> identified on the Certificate of Conformance.
>
> (Added 2003)

# N. Notes

**N.1. Test Liquid.** - A meter shall be tested with water.

**N.2. Evaporation and Volume Change.** - Care shall be exercised to
reduce to a minimum, evaporation losses and volume changes resulting
from changes to tempera­ture of the test liquid.

**N.3. Test Drafts.** - Test drafts should be equal to at least the
amount delivered by the device in 2 minutes and in no case less than the
amount delivered by the device in 1 minute at the actual maximum flow
rate developed by the installation. The test draft sizes shown in Table
N.4.1. Flow Rate and Draft Size for Water Meters Normal Tests, shall be
followed as closely as possible.

(Amended 2003)

**N.4. Testing Procedures.**

> **N.4.1. Normal Tests.** - The normal test of a meter shall be made at
> the maximum discharge rate developed by the installation. Meters with
> maximum gallon per minute ratings higher than the values specified in
> Table N.4.1. Flow Rate and Draft Size for Water Meters Normal Tests
> may be tested up to the meter rating, with meter indications no less
> than those shown.
>
> (Amended 1990, 2002, and 2003)

+----------------+-----------------+----------------+-----------------+
| **Table N.4.1. |                 |                |                 |
| Flow Rate and  |                 |                |                 |
| Draft Size for |                 |                |                 |
| Water Meters** |                 |                |                 |
|                |                 |                |                 |
| #              |                 |                |                 |
| # Normal Tests |                 |                |                 |
+----------------+-----------------+----------------+-----------------+
| **Meter Size** | **Rate of       | **Maximum      |                 |
|                | Flow**          | Rate**         |                 |
| **(inches)**   |                 |                |                 |
|                | **(gal/min)**   |                |                 |
+----------------+-----------------+----------------+-----------------+
|                |                 | **Meter        |                 |
|                |                 | I              |                 |
|                |                 | ndication/Test |                 |
|                |                 | Draft**        |                 |
+----------------+-----------------+----------------+-----------------+
|                |                 | **gal**        | **ft^3^**       |
+----------------+-----------------+----------------+-----------------+
| Less than      | 8               | 50             | 5               |
| ^5^/8          |                 |                |                 |
+----------------+-----------------+----------------+-----------------+
| ^5^/8          | 15              | 50             | 5               |
+----------------+-----------------+----------------+-----------------+
| ¾              | 25              | 50             | 5               |
+----------------+-----------------+----------------+-----------------+
| 1              | 40              | 100            | 10              |
+----------------+-----------------+----------------+-----------------+
| 1½             | 80              | 300            | 40              |
+----------------+-----------------+----------------+-----------------+
| 2              | 120             | 500            | 40              |
+----------------+-----------------+----------------+-----------------+
| 3              | 250             | 500            | 50              |
+----------------+-----------------+----------------+-----------------+
| 4              | 350             | 1000           | 100             |
+----------------+-----------------+----------------+-----------------+
| 6              | 700             | 1000           | 100             |
+----------------+-----------------+----------------+-----------------+
| (Table Added   |                 |                |                 |
| 2003)          |                 |                |                 |
+----------------+-----------------+----------------+-----------------+

> **N.4.1.1. Repeatability Tests.** - Tests for repeatability should
> include a minimum of three consecutive test drafts of approximately
> the same size and be conducted under controlled conditions where
> variations in factors, such as temperature, pressure, and flow rate
> are reduced to the extent that they will not affect the results
> obtained.
>
> (Added 2002)
>
> **N.4.2. Special Tests.** - Special tests to develop the operating
> characteristics of meters may be made according to the rates and
> quantities shown in Table N.4.2. Flow Rate and Draft Size for Water
> Meters Special Tests.
>
> (Amended 2003)

+---------+---------+----------+--------+---------+---------+---------+
| **Table |         |          |        |         |         |         |
| N.4.2.  |         |          |        |         |         |         |
| Flow    |         |          |        |         |         |         |
| Rate    |         |          |        |         |         |         |
| and     |         |          |        |         |         |         |
| Draft   |         |          |        |         |         |         |
| Size    |         |          |        |         |         |         |
| for     |         |          |        |         |         |         |
| Water   |         |          |        |         |         |         |
| M       |         |          |        |         |         |         |
| eters** |         |          |        |         |         |         |
|         |         |          |        |         |         |         |
| **      |         |          |        |         |         |         |
| Special |         |          |        |         |         |         |
| Tests** |         |          |        |         |         |         |
+---------+---------+----------+--------+---------+---------+---------+
| **Meter | **Inter |          |        | **      |         |         |
| Size**  | mediate |          |        | Minimum |         |         |
|         | Rate**  |          |        | Rate**  |         |         |
| **(in   |         |          |        |         |         |         |
| ches)** |         |          |        |         |         |         |
+---------+---------+----------+--------+---------+---------+---------+
|         | **Rate  | **Meter  |        | **Rate  | **Meter |         |
|         | of      | Indicat  |        | of      | I       |         |
|         | Flow**  | ion/Test |        | Flow**  | ndicati |         |
|         |         | Draft**  |        |         | on/Test |         |
|         | **(gal  |          |        | **(gal  | Draft** |         |
|         | /min)** |          |        | /min)** |         |         |
+---------+---------+----------+--------+---------+---------+---------+
|         |         | **gal**  | **f    |         | **gal** | **      |
|         |         |          | t^3^** |         |         | ft^3^** |
+---------+---------+----------+--------+---------+---------+---------+
| Less    | 2       | 10       | 1      | ¼       | 5       | 1       |
| than or |         |          |        |         |         |         |
| equal   |         |          |        |         |         |         |
| to      |         |          |        |         |         |         |
| ^5^/8   |         |          |        |         |         |         |
+---------+---------+----------+--------+---------+---------+---------+
| ¾       | 3       | 10       | 1      | ½       | 5       | 1       |
+---------+---------+----------+--------+---------+---------+---------+
| 1       | 4       | 10       | 1      | ¾       | 5       | 1       |
+---------+---------+----------+--------+---------+---------+---------+
| 1½      | 8       | 50       | 5      | 1½      | 10      | 1       |
+---------+---------+----------+--------+---------+---------+---------+
| 2       | 15      | 50       | 5      | 2       | 10      | 1       |
+---------+---------+----------+--------+---------+---------+---------+
| 3       | 20      | 50       | 5      | 4       | 10      | 1       |
+---------+---------+----------+--------+---------+---------+---------+
| 4       | 40      | 100      | 10     | 7       | 50      | 5       |
+---------+---------+----------+--------+---------+---------+---------+
| 6       | 60      | 100      | 10     | 12      | 50      | 5       |
+---------+---------+----------+--------+---------+---------+---------+
| (Table  |         |          |        |         |         |         |
| Added   |         |          |        |         |         |         |
| 2003)   |         |          |        |         |         |         |
+---------+---------+----------+--------+---------+---------+---------+

> **N.4.3. Batching Meter Tests.** - Tests on batching meters should be
> conducted at the maximum and intermediate rates only.

# T. Tolerances

**T.1. Tolerance Values.** - Maintenance and acceptance tolerances shall
be as shown in Table T.1. Accuracy Classes and Tolerances for Water
Meters.

(Amended 2003)

+-------+----------+----------+---------+----------+-----------------+
| ####  |          |          |         |          |                 |
| ##### |          |          |         |          |                 |
|  Tabl |          |          |         |          |                 |
| e T.1 |          |          |         |          |                 |
| . Acc |          |          |         |          |                 |
| uracy |          |          |         |          |                 |
|  Clas |          |          |         |          |                 |
| ses a |          |          |         |          |                 |
| nd To |          |          |         |          |                 |
| leran |          |          |         |          |                 |
| ces f |          |          |         |          |                 |
| or Wa |          |          |         |          |                 |
| ter M |          |          |         |          |                 |
| eters |          |          |         |          |                 |
+-------+----------+----------+---------+----------+-----------------+
| **Acc | **Appli  |          | **Acc   | **Mai    | **Tolerance for |
| uracy | cation** |          | eptance | ntenance | Special Tests   |
| Cl    |          |          | Tole    | Tol      | Conducted at    |
| ass** |          |          | rance** | erance** | the Minimum     |
|       |          |          |         |          | Flow Rate**     |
+-------+----------+----------+---------+----------+-----------------+
| 1.5   | Water,   | #######  | 1.5 %   | 1.5 %    | 1.5 %           |
|       | Other    | Overregi |         |          |                 |
|       | Than     | stration |         |          |                 |
|       | M        |          |         |          |                 |
|       | ulti-Jet |          |         |          |                 |
|       | Water    |          |         |          |                 |
|       | Meters   |          |         |          |                 |
+-------+----------+----------+---------+----------+-----------------+
|       |          | U        | 1.5 %   | 1.5 %    | 5.0 %           |
|       |          | nderregi |         |          |                 |
|       |          | stration |         |          |                 |
+-------+----------+----------+---------+----------+-----------------+
| 1.5   | Water,   | Overregi | 1.5 %   | 1.5 %    | 3.0 %           |
|       | M        | stration |         |          |                 |
|       | ulti-Jet |          |         |          |                 |
|       | Water    |          |         |          |                 |
|       | Meters   |          |         |          |                 |
+-------+----------+----------+---------+----------+-----------------+
|       |          | U        | 1.5 %   | 1.5 %    | 3.0 %           |
|       |          | nderregi |         |          |                 |
|       |          | stration |         |          |                 |
+-------+----------+----------+---------+----------+-----------------+
| (     |          |          |         |          |                 |
| Table |          |          |         |          |                 |
| Added |          |          |         |          |                 |
| 2003) |          |          |         |          |                 |
+-------+----------+----------+---------+----------+-----------------+

**T.1.1. Repeatability.** - When multiple tests are conducted at
approximately the same flow rate, the range of the test results shall
not exceed 0.6 % for tests performed at the normal and intermediate flow
rates, and 1.3 % for tests performed at the minimum flow rate, and each
test shall be within the applicable tolerance.

(Added 2002)

# UR. User Requirements

**UR.1. Batching Meters Only.**

> **UR.1.1. Strainer.** - A filter or strainer shall be provided if it
> is deter­mined that the water contains excessive amounts of foreign
> material.
>
> **UR.1.2. Siphon Breaker.** - An automatic siphon breaker or other
> effective means shall be installed in the discharge piping at the
> highest point of outlet, in no case below the top of the meter, to
> prevent siphoning of the meter and permit rapid drainage of the pipe
> or hose.
>
> **UR.1.3. Provision for Testing.** - Acceptable provisions for testing
> shall be incorporated into all meter systems. Such provisions shall
> include a two-way valve, or manifold valving, and a pipe or hose
> installed in the discharge line accessible to the proper positioning
> of the test measure.

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