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ACEEE Hot Water Forum 2011
Steven L. Barfuss
Utah State University
Accuracy of In-Service Water Meters at Low
and High flow Rates – Project No. 4028
Sponsored by The Water Research Foundation
Formally known as the AWWA Research Foundation
Four Year Project
Started:
Completion Date:
Final Report Submitted:
October 2006
October 2010
March 2011
RESEARCH COMPONENTS
• Cold Water
• New meter accuracies
• Meter accuracy as a function of throughput
• Pulled meter accuracies
• Low and high flow rate accuracies
• Effect of particulates on accuracy
Accuracy tests performed at the new
condition, 25%, 50%, 75% and 100% of the
meter’s expected life.
PROJECT ENCOMPASSED……..
• Meters from 15 US manufacturers
• 5/8 x 3/4- through 2-inch sizes
• Wide range of flow rates
• Involvement of twelve utilities
• Meters were purchased through local
distributors and not directly from the
manufacturer
• Extreme quality control on measurement
equipment and procedures (NIST traceability)
• Data management
METER TYPES
ND:
DP:
MJ:
SJ:
FO:
TU:
PR:
Nutating Disc (Positive Displacement)
Displacement Piston (Positive Displacement)
Multi-Jet
Single-Jet
Fluidic Oscillator
Turbine
Propeller
AWWA Flow Accuracy Standards
5/8 x 3/4 –inch Maximum Flow Rate
Type Flow (gpm) Upper (%) Lower (%)
DP
15
101.5
98.5
ND
15
101.5
98.5
FO
15
101.5
98.5
SJ
15
101.5
98.5
MJ
15
101.5
98.5
5/8 x 3/4 inch meters
AWWA Flow Accuracy Standards
5/8 x 3/4 –inch Intermediate Flow Rate
Type Flow (gpm) Upper (%) Lower (%)
DP
2
101.5
98.5
ND
2
101.5
98.5
FO
2
101.5
98.5
SJ
1
101.5
98.5
MJ
1
101.5
98.5
5/8 x 3/4 inch meters
AWWA Flow Accuracy Standards
5/8 x 3/4 ‐inch Minimum Flow Rate
Type Flow (gpm) Upper (%) Lower (%)
DP
1/4
101
95
ND
1/4
101
95
FO
1/4
101
95
SJ
1/4
101.5
95
MJ
1/4
103
97
5/8 x 3/4 inch meters
This research included flow rates above and
below the AWWA flow standards, a topic that
had not been studied in depth in the past.
•1/64 gpm
•1/32 gpm
•1/16 gpm
•1/8 gpm
•1/4 gpm
•1/2 gpm
•1 gpm
•2 gpm
•15 gpm
•20 gpm
AWWA low flow for all meters
AWWA inter. flow for SJ and MJ
AWWA inter. flow for DP, ND, FO
AWWA high flow for all meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
New Meter Tests:
• A larger-than-expected percentage of new
meters failed one or more of the three AWWA
flow accuracy standards.
• These same meters are reported and
advertised to meet the AWWA accuracy
standards.
• One manufacturer was able to meet the AWWA
standard at all three flow rates (for new meters in all
sizes and types offered) more than 95% of the time.
• None of the other 14 manufacturers were able to
exceed a success percentage greater than 85%.
• In contrast, a second manufacturer’s new meters only
met the AWWA standard at all three flow rates 17% of
the time.
• Seven manufacturers only passed all three AWWA
standard flow rates 50% of the time or less.
Number/percent passing AWWA standard
Meter type
Low
Intermediate
Maximum
DP (48)
37 77% 43
90%
48
100%
MJ (42)
32 76% 37
88%
38
90%
ND (30)
30 100% 27
90%
30
100%
SJ (24)
18 75% 18
75%
18
75%
FO (6)
6 100% 6
100%
6
100%
Overall (150) 123 82% 131 87% 140
93%
5/8 x 3/4 inch meters
Specific Minimum Flow Pass Rates for Single-Jet Meter Manufacturers
Single-Jet Manufacturer
Met Minimum AWWA Flow
Total Meters Tested
A
6
6
B
2
6
C
6
6
D
4
6
5/8 x 3/4 inch meters
A study performed in 1999 indicated that homes
on average have a leak of 21.9 gpd, while 5.5
% of the homes included in the study leaked
more than 100 gpd (AWWARF, 1999)
All Homes
152 drips/min
5.5%
of all
homes
Continuous Toilet
Leak
Endurance Tests:
• The Multi-Jet, Single-Jet and Piston meters indicated
the highest amount of accuracy degradation after a full
life cycle of throughput.
•The Nutating Disc and Fluidic Oscillator meters
maintained the highest registries at the lowest flow rates
both in the new condition and after a full life cycle of
throughput.
Meter
type
5/8x3/4 ND
5/8x3/4 ND
5/8x3/4 ND
5/8x3/4 DP
5/8x3/4 DP
5/8x3/4 DP
5/8x3/4 MJ
5/8x3/4 MJ
5/8x3/4 MJ
5/8x3/4 SJ
5/8x3/4 SJ
5/8x3/4 SJ
5/8x3/4 FO
5/8x3/4 FO
5/8x3/4 FO
No. of
meters
30
30
30
48
48
48
42
42
42
24
24
24
6
6
6
Test
flow
0.25
2
15
0.25
2
15
0.25
1
15
0.25
1
15
0.25
2
15
Meters passing AWWA standard at throughput
0 MG
0.5 MG
1 MG
1.5 MG
30
28
30
25
27
29
30
25
30
20
18
19
37
32
31
33
43
41
44
42
48
44
46
44
22
11
15
9
37
38
33
35
38
33
32
27
18
21
22
20
18
17
14
11
18
16
14
14
6
6
6
6
6
6
6
6
6
6
6
6
2 MG
28
25
19
27
42
43
8
35
24
17
14
14
6
6
5
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
5/8 x 3/4 inch meters
Pulled Meter Tests:
• There was no significant correlation between meter
performance and throughput or meter performance and
age.
• There was however, a significant number of utilityprovided pulled meters that did not function (~7%)
Particulate Tests:
• Sand particulates had the greatest affect on the Piston meter
type (initially and after throughput).
• The Nutating Disc and Piston type meters showed accuracy
degradation affects at the minimum AWWA flow rate over a full life
cycle of throughput.
•The Piston and Single-Jet type meters showed accuracy
degradation affects at the maximum AWWA flow rate over a full life
cycle of throughput.
• Multi-jet and Fluidic Oscillator type meters were the least affected
by sand particulates.
Pre-Particulate 0-Life Meter Summary
105%
100%
Registry
95%
90%
85%
80%
0.13
11.25
1/4
12.50 15
2
Flow (gpm)
DP
SJ
ND
MJ
FO
Particulate 0-Life Meter Summary
105%
100%
Registry
95%
90%
85%
80%
0.13
11.25
1/4
12.50 15
2
Flow (gpm)
DP
SJ
ND
MJ
FO
Particulate Full-Life Meter Summary
105%
100%
Registry
95%
90%
85%
80%
0.13
11.25
1/4
12.50 15
2
Flow (gpm)
DP
SJ
ND
MJ
FO
Particulate 5/8 x 3/4-inch Multi-jet Registry Summary
110%
100%
90%
80%
Registry
70%
60%
50%
40%
30%
20%
10%
0%
0.01
0.10
Before
1/4
0 MG
1
2
1.00
Flow (gpm)
0.5 MG
1.0 MG
15
10.00
1.5 MG
2.0 MG
100.00
Benefits & Features:
Operates up to 194 degrees Fahrenheit Meets All AWWA Standards Tamper Detection and Prevention High‐Quality, Long‐Life Parts Durable Basket Strainer Protects From Damage Hot Water Meters - 5/8" to 2"
Velocity-type meter meeting or exceeding the performance
requirements of AWWA Standard C-708.
Hot Water Meters:
• Meter types are the same as cold water
• Manufacturers state that metering
components are higher quality, but internal
working parts look identical
Benefits & Features:
Operates up to 194 degrees Fahrenheit Meets All AWWA Standards Tamper Detection and Prevention High‐Quality, Long‐Life Parts Durable Basket Strainer Protects From Damage Hot Water Meters - 5/8" to 2"
Velocity-type meter meeting or exceeding the performance
requirements of AWWA Standard C-708.
AWWA Standard C-708 is a Multi-jet cold water standard
Hot Water Meters:
• No AWWA standards for hot water meters
• Consequently, no hot water facility to certify
accuracy of hot water meters
• The State of California was the first to
specify hot water standards for sub-metering
The AWWA M6 manual states:
“All new meters should be tested for accuracy
of registration at flow rates and test-flow
quantities in accordance with Table 5-3 before
they are placed in service.”
This requirement is an essential component to
ensuring that meters placed in the marketplace
are operating accurately.
Only 65% of the 450 new meters that were
purchased came with certificates like this one.
End users should ensure that each meter they
purchase includes a calibration……
• with a certification that the meter was tested
as a complete unit
• that it was calibrated at each of the required
flow rates and
• that the meter registered flows that met the
AWWA requirements.
All meters of all types and sizes lose
accuracy (at some point) at very low flow
rates.
Utilities have to balance the cost of
technologically advanced meters and the
expected revenue from less accurate,
more affordable meters.
New meters types on the market:
• Magnetic
• Ultrasonic
• New mechanical models
Accuracy certification is critical to a
system’s economic success.