EPA
WaterSense
Comments on WaterSense® Notice of Intent to
Develop a Draft Specification for Spray Sprinkler
Nozzles
April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Table of Contents
Jay Guthy, Toro 1
Nicolle Miller, East Bay Municipal Utility District 2
Paul Jeffrey Knopp, Behnke Landscape Architecture 3
R. Troy Peters, P.E., Ph.D., Washington State University 6
Nathan Bowen, Irrigation Association 10
Kevin Hartley, Town of Windsor, Colorado 12
Kelsey Jacquard, Hunter Industries 14
Paul Lauenstein 22
Ron Wolfarth, Rain Bird 25
Andrew Morris, Alliance for Water Efficiency 48
Ryan Moore, New York State Energy Research and Development Authority
(NYSERDA) 51
Tres Wangsgaard, Orbit Irrigation, LLC / Hydro-Rain 53
Nathan Bowen, Irrigation Association 59
Eric S. Neustrup, City of Bozeman's Water Conservation Division 62
Chris Davey, The Toro Company 68
Kris Loomis, Sonoma County Water Agency 70
EPA
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April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Jay Guthy
Affiliation: Toro
Comment Date: December 7, 2022
Email Text:
Hello,
I read the note from EPA on Spray Sprinkler Nozzle Specification performance. Kudos
to the EPA for considering such an action.
Recent specifications in many states now requiring PR in spray bodies is a step in the
right direction. But it's a small step and often, a misguided one. Reducing pressure in a
spray body with a high precipitation (precip) rate does reduce the application rate of
water. HOWEVER, the mandate says nothing of requiring an efficient spray nozzle on a
PR body, thus improving the EFFICIENCY of the overall device.
Having an inefficient (low-uniform, high precip nozzle) on a PR body has minimal
positive impact. I would much prefer a highly uniform and efficient nozzle on a non-PR
body vs. the opposite scenario just described.
The most efficient nozzle in the industry is Toro's Precision Spray Nozzle and it's not
really close. The nozzle has a lower, 1.0 inch/hr. Precip rate and high
uniformity. Uniformity in some cases over .8. All equally matched precip. You can
NEVER have high efficiency with a low uniform (55% or less) nozzle. It's the theoretical
high threshold of efficiency. The weak-link in the chain, if you will.
Toro's competitors may be unlikely to support such a Specification as none possess
such a highly uniform nozzle. Hunter's MP Rotator has a low Precip rate but their
uniformity is also low, requiring higher run times (SC) to account for the lack of
uniformity.
So be prepared for a lack of response and support of such an action on your
part. Toro's marketing department can be a resource for additional information you may
seek. Thanks for pursuing such an action. It's long-overdue.
Kindly,
Jay GuthyP
P. Jay Guthy, CLIA, CIT
Regional Sales Manager, Toro, Irritrol & Unique Lighting
860-918-4567
iav.guthv@toro.com
Irritrol unique
for proOnly ' LIGHTING SYSTEMS*
EPA
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WaterSense
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April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Nicolle Miller
Affiliation: East Bay Municipal Utility District
Comment Date: December 14, 2022
Email Text:
Good morning,
I am interested in finding out more about the development of a WaterSense
specification for spray sprinkler nozzles and would like to be added to the
stakeholder list.
Best,
Nicolle Miller
Water Conservation Representative
East Bay Municipal Utility District
P: 510.986.7615 | C: 510.213.8606 | E: nicolle.miller@ebmud.com
EAST BAY
MUNICIPAL UTILITY DISTRICT
stewardship integrity respect teamwork
EPA
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WaterSense
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April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Paul Jeffrey Knopp
Affiliation: Behnke Landscape Architecture
Comment Date: December 19, 2022
Email Text:
See attached.
EPA
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WaterSense
P. Jeff Knopp, ASLA | LEED AP
Principal
be nke
LANDSCAPE ARCHITECTURE
2658 Scranton Road, Suite 2
Cleveland, OH 44113
216.589.9100
WWW.BEHNKELA.COM
Email Attachment:
See pages 4 through 5.
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Template for Public Comment Submission on WaterSense Documents
Commenter Name: Paul Jeffrey Knopp
Commenter Affiliation: Irrigation Association Certified Irrigation Designer
Date of Comment Submission: 12/19/22
Topic: Definition of "spray sprinkler nozzle."
Comment: NOI Text says "There is no explicit definition for spray sprinkler nozzles
within ASABE/ICC 802-2020, so for the purpose of this NOI, WaterSense developed
the following definition based on related definitions included in the standard:
• Spray sprinkler nozzle: The discharge opening of a spray sprinkler used to
control the volume of discharge, distribution pattern, and droplet size. These
nozzles are attached to spray sprinkler bodies that do not contain components
to drive the rotation of the nozzle during operation and lack an internal control
valve.
Though the general product category of spray sprinkler nozzles is not defined, the
ASABE/ICC 802-2020 standard defines one specific type of spray sprinkler nozzle:
• Multi-stream, multi-trajectory (MSMT) nozzles: Nozzles designed to distribute
discharge water in a number of individual streams, of varying trajectories,
which rotate across the distribution.
MSMT sprinkler nozzles are only available as rotating models. The rotation is driven
by the nozzle, not the spray sprinkler."
Rationale: While the definition itself is fine, not sure why you confuse the issue by
introducing the MSMT nozzle as a subset of spray sprinkler nozzles. If you are going
to introduce MSMT nozzles as a subset, then you should also introduce Fixed Spray
Sprinkler nozzles as a subset, or don't introduce MSMT's at all.
Suggested Change (or Language): Add to above:
• "Fixed Spray Sprinkler Nozzle: A nozzle intended to distribute a spray of
discharge water without rotation across the distribution."
Topic: Text Under Figure 4
Comment: NOI Text says: "WaterSense is not aware of any versions of MSMT
nozzles for rotor sprinklers."
Rationale: I believe that the The Stream Rotor 300 Series from Toro has an MSMT
nozzle for rotors. Rainbird used to make one, but not sure that they do anymore.
Suggested Change (or Language): I would just take the sentence out of the text
as it does not really apply to the standard.
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Topic: Figure 4
Comment: The diagram uses the text "Standard spray sprinkler
Nozzle"
Rationale: This is confusing text.
Suggested Change (or Language): Change to "Fixed Spray Sprinkler Nozzle"
Topic: General
Comment: Figure 4 is as far as I got. This was enough for me to determine that this
NOI is poorly written.
Rationale: You really need someone (or multiple persons) who has/have been in
the industry for many years to be paid by you to review the NOI. You cannot expect
my boss (or anyone's boss) to pay me (or anyone) to review your work.
Suggested Change (or Language): This NOI needs lots of editing.
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April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: R. Troy Peters, P.E., Ph.D.
Affiliation: Washington State University
Comment Date: January 10, 2023
Email Text:
Quick introduction: I'm a professor of irrigation engineering and have been doing
irrigation research and have been an extension irrigation specialist in the dry side of
Washington state for over 20 years. I learned about this through ASABE where I have
served as the chair of the sprinkler irrigation committee for a few years and am currently
the chair of the irrigation parent committee NRES-24.
Below are some thoughts/suggestions on this draft specification.
Overall, I agree with this standard and that this specification should be
developed. MSMT nozzles should be more widely used. The increased adoption of
these is generally in the best interest of everyone, including irrigation contractors,
homeowners, and the public at large.
The scale of water savings possible in agriculture dwarfs that of landscape
irrigation. LEPA/LESA sprinklers on center pivots have proven to save 15-20% of the
water in agricultural irrigation. These should be given the WaterSense designation as
well.
Page 7: Those 4 attributes are specific to MSMT nozzles. If you want to expand this by
defining HES nozzles, then these should be left out. I think it is OK to just avoid the
whole "HES" designation and make this about MSMT nozzles in particular.
Equation 1 is for the gross application rate and does not account for wind drift and
evaporation losses. Reducing these losses is the point of this new designation for HES
spray nozzles. Net application rate (gross rate - losses before it hits the ground) is most
relevant for irrigation management. This requires the inclusion of an application
efficiency (Ea) term. i.e. Net application rate is that equation multiplied by application
efficiency (Ea) as a % divided by 100, or as a decimal.
Page 8: Lower application rates ONLY result in higher efficiency if there would be runoff
otherwise. If all else is the same, and the soil can take the water in at a higher
application rate without runoff, then the higher application rate is more efficient because
there is less time for water losses to wind drift and evaporation from the operating
sprinkler and from water evaporation from a wet plant and soil surface. For example,
what is better, a sprinkler that applies water extremely slowly, but runs all day with a
constantly wet plant and soil surface and with water flying through the air non-stop, or
one that can get all the water into the soil in a few minutes and leaves the irrigated
surface dry and keeps water out of the air for the vast majority of the time? A caveat: In
practice, this efficiency improvement due to reduced evaporation from a wet plant and
soil surface because of reduced application time of non-MSMT nozzles may be small.
Matched precipitation rates are most useful for good irrigation system design. Without it,
half-circles and corners would need smaller nozzles (1/2 and 1/4 of the flow rate of a full
circle sprinkler respectively) to match precipitation rates of full-circle sprinklers within a
EPA
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
single zone in order to ensure good application uniformity. Designers don't always do
this or can't do it practically. Thus, matched precipitation is often better. But not
always. It is possible to get similar uniformities without matched precipitation
sprinklers. For example, if all the half-circle sprinklers are in the same zone and that
zone is run at 1/2 of the runtime of the full-circle sprinklers, the uniformity would be the
same as matched precipitation. Or, if there is the same amount of overlap between
application areas from 1/2 circle sprinklers with full sprinklers the uniformity may still be
good even if they are on the same zone and have the same flow rate. These conditions
are hard to set up, and a knowledgeable and experienced designer would have to do it,
which isn't always the case. Thus, in general, better designs are achieved with matched
precipitation sprinklers. They make good design and zone setup so much simpler.
Page 9: Using application rate as a water efficiency or performance criteria doesn't make
sense. See above. Matched precipitation could be used, but not overall application
rate.
Increased wetted radius means fewer sprinklers are required and lower application
rates, both of which are good, and can increase efficiency if it would otherwise cause
runoff, but runoff is uncommon in landscape irrigation systems. When present, runoff is
usually managed by more frequent, but shorter run times. The reduced piping and
trenching required by using sprinklers with larger wetted diameters can mean that the
same results, if not better, can be accomplished with less pipe, sprinklers, and
digging. This reduced input and installation costs should increase profit opportunity for
contractors.
Page 12: Landscapes with lower DU don't use more water. They lose more
water. There are more water losses to deep percolation in order to adequately irrigate
all areas.
Higher DUs don't always result in increased water savings primarily because of human
behavior. People don't irrigate less to compensate for an improved system DU.
A threshold DU used in agriculture for chemigation is 0.8. That should be possible and
is reasonable to expect in landscape irrigation.
The water stream pattern from MSMT nozzles allows the droplets to draft behind the
droplets in front of them, allowing for greater wetted radii as well as reduced evaporation
(because of reduced air resistance and air that is already saturated with water from the
droplets in front) on the way to the soil (greater application efficiency). Larger droplets =
less total surface area exposed to evaporation on the way to the soil surface = higher
application efficiency. Larger droplets also have more momentum in comparison with
the air resistance that is trying to slow them down and thus they fly further also
contributing to a greater wetted radius. The slow rotation speed of the MSMT nozzle
streams allocates the pressure force to increased droplet velocity instead of absorbing
that force/energy to spin the sprinkler or losing that force/energy to breaking up the
water surface tension into smaller droplets. Some rotation movement is necessary for
improved uniformity. The pressure/energy from very high pressures (> 80 psi) goes to
breaking up water droplets into smaller droplets (breaking the surface tension) and thus
the benefits from large droplets (improved efficiency and larger wetted radius)
diminishes.
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Pressure regulation is not always needed or necessary and doesn't always result in
improved overall irrigation efficiency. If the area if flat and if there are little pressure
losses in the system (i.e. the nozzle pressures at the base of the sprinkler are constant
and predictable) then spending resources on pressure regulators is wasteful. If there
are significant pressure differences due to elevation differences or pressure losses in the
system, then pressure regulators can greatly improve the performance (DU) of the
system.
Page 9:
Overall irrigation efficiency (water flowing onto an area divided by the water that is used
by the plants), which is a function of DU as well as the application efficiency (Ea) (water
that can be collected in a catch can divided by the gross depth that should be caught
from the application rate; Equation 1), is what we are after more than the wetted radius
or application rate. A test method that measures DU can also measure application rate
AND overall irrigation efficiency if the flow rates of the nozzles can be measured or
accurately estimated. The irrigation system evaluation methods (Ea and DUIq) using
catch cans are well known, taught, and practiced and the Irrigation Association teaches
these classes and has certifications for them. To get to application efficiency (Ea), the
gross application depths needs to be determined (net catch depth from the catch cans
divided by the gross catch depth from Eq. 1). This can be measured from the flow rates
of the nozzles and application area each nozzle is assigned to. This requires a bit more
data collection, but is possible and not overly time consuming. Ea is then the mean
catch can depth in the are divided by this calculated gross depth. A rough method of
estimating overall irrigation efficiency (IE) is application efficiency (Ea) multiplied by the
distribution uniformity of the low quarter (DUIq). IE = Ea * DUIq. Of course, both terms
need to be as a decimal (%/100) instead of as a %. Multiplication by DUIq assumes that
75% of the area will be over-irrigated in order to adequately irrigate the low
quarter. MSMT sprinkler heads should shine in both DUIq measurements as well as Ea.
The Irrigation Training and Research Center in California (http://www.itrc.org/) might be
a well-known, and respected third-party for testing DUIq and Ea for these different
nozzles under standardized conditions. In reality this way of defining IE still doesn't
perfectly capture the total irrigation efficiency according to many people's definitions
since a perfectly functioning system can still be mismanaged by running it longer than
necessary, however irrigation scheduling and changing human behavior around these
systems is likely outside the scope of WaterSense.
People need to learn to adjust their application times for the lower application rates of
MSMT sprinklers. They need to learn to adjust them in general! Even most installers
don't know how to set run times properly. It is better if they can adjust the time between
irrigations (irrigation frequency) rather than the run time or application depth of individual
irrigation events. The suggested irrigation frequency for each zone and how these need
to change throughout the season should be a required output of the irrigation system
design. I'm aware that overcoming these problems is the goal of Smart Controllers.
Page 22:
The percent of water used outdoors is a gigantic function of the climatic region, the
weather, and the time of year. These change drastically. I'm not sure it is relevant or
important to what you are trying to accomplish here, however. The payback time
estimate is a rough estimate based on a large number of hidden assumptions, but I think
it's OK to leave it as it is as it generally shows that people will get their money
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
back. They more they need to irrigate, or the longer the required run times in a season,
the shorter the payback time will be and thus the stronger the financial incentive for
converting.
Your assumptions that people don't fix something that they don't perceive as broken is
spot on. Whether broken heads get replaced with an appropriate or similar head is
questionable. I don't have any answers or suggestions for this however, except
improved education.
Application rate is not a good surrogate for irrigation efficiency.
Hope this is helpful and useful!
Troy
R. Troy Peters, P.E., Ph.D.
Professor and Extension Irrigation Engineer
Washington State University
Irrigated Agriculture Research and Extension Center
24106 N. Bunn Rd., Prosser, WA 99350
troy peters@wsu.edu
509-786-9247
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Commenter: Nathan Bowen
Affiliation: Irrigation Association
Comment Date: January 20, 2023
Email Text:
Attached, please find a request for an extension of the comment period for the Spray
Sprinkler Nozzle NOI.
Regards,
Nathan Bowen
Advocacy Director
Irrigation Association
8280 Willow Oaks Corporate Drive, Suite 630 | Fairfax, VA 22031
C: 202-209-9091 | F: 703.536.7019
nathanbowen@irriqation.org | www.irriqation.org
The IA is ready to work with you in 2023!
Start the year off with a bang and enhance your industry knowledge with the iA's education
resources.
Email Attachment:
See page 11.
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April 26, 2023
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8280 Willow Oaks Corporate Drive, Suite 6301 Fairfax, VA 22031
Tel: 703.536.70801 Fax: 703.536.7019
www.irrigation.org
January 20, 2023
U.S. Environmental Protection Agency
WaterSense Program
1200 Pennsylvania Avenue NW
Washington, DC 20004
Re: Comment Period Extension Request for WaterSense Notice of Intent to Develop a Draft
Specification for Spray Sprinkler Nozzles
To whom it may concern:
On behalf of the approximately 1,300 member companies of the Irrigation Association, I write to request
a 60-day extension of the comment period with respect to the WaterSense Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles.
The Irrigation Association represents experts in all aspects of irrigation, including agriculture, landscape,
turfgrass and golf. Irrigation manufacturers, distributors and contractors have proudly partnered with
WaterSense since its inception to strengthen the marketplace for efficient water-use technologies and
practices. Since it was launched in 2006, WaterSense has fostered successful collaboration between the
industry, public and private water providers, and the federal government to expand the water-efficient
product marketplace.
We appreciate the opportunity to review and comment on this Notice of Intent on behalf of the entire
irrigation industry. In order to ensure the interests of all the impacted elements of the industry are taken
into account, we respectfully request additional time to gather input and feedback on the proposal.
Additional time would allow the opportunity for more robust and comprehensive feedback to the
program.
Thank you for your consideration of this request. Please contact Nathan Bowen
(nathanbowen@irrigation.org), Irrigation Association advocacy director, for additional information.
Sincerely,
Chief Executive Officer
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April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Kevin Hartley
Affiliation: Town of Windsor, Colorado
Comment Date: January 26, 2023
Email Text:
Good morning;
I am writing to address the WaterSense Spray Nozzle NOI.
Although there are rotary nozzles that affix to spray bodies of which some should have
the WaterSense label of approval, I have to strongly advise against giving ANY spray
nozzle receiving such accommodations. Doing so would be a great disservice to
American consumers, as there are no spray nozzles that work in an efficient manner
anywhere near.70 distribution uniformity (DU). I have been an auditor for many years
and assessed over 5000 residential, commercial and industrial systems, and the ONLY
time I have measured a DU of.70 DU was when the pressure was too high, the zone
was crowded (too many heads for the area), and there was a great deal of overspray.
The best I have measured for Rain Bird MPRs on PRS 30/SAM heads was a.58 DU and
a precipitation rate of 1.58" an hour. OF all spray nozzles on the market Rain Bird
Matched Precipitation Rate (MPR) Nozzles have performed the best compared to other
models and manufacturers, which is stating much, considering the poor performance
provided by the MPRs. You can count the TORO Precision sprays in that statement as
well, which one would think performed the best of all sprays, but real-world testing has
proven quite the contrary.
Precipitation rate is the other issue with spray nozzles, they apply water far too quickly to
prevent runoff from the landscape and require such a short cycle with a cycle and soak
program to prevent runoff, the run times get too short to be effective when adjusting for
seasonality, causing the owner to adjust run times up to compensate, thus overwatering.
In my professional opinion, granting WaterSense labeling to any spray nozzle only
weakens your mission, and reliability and waters down (Pun Intended) the EPA's
reputation.
As a water conservation specialist, I use your certification as a measure for eligibility for
rebates of certain irrigation equipment, and certifying spray nozzles go against the water
efficiency technologies we are trying to promote. We would have to drop the promotion
of the WaterSense label in order to continue our mission if it comes to pass.
I hope you will take this into consideration as you move forward, and I can provide test
data if you would like.
Thank you for your time and commitment,
EPA
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WaterSense
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April 26, 2023
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WaterSense
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Tgwm cm
WINDSOR
PARKS, «eC«EATlON
& CULTURE
Kevin Hartley
Water Conservation Technician
Town of Windsor, Colorado
Parks, Recreation & Culture | Open Space &
Trails
922 15th St., Windsor, CO 80550
Office: 970-674-6687
Cell: 970-460-4339
recreationliveshere.com
13
April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Kelsey Jacquard
Affiliation: Hunter Industries
Comment Date: March 21, 2023
Email Text:
Hello,
Thank you for opening up the Spray Sprinkler Nozzle NOI to comments and
suggestions. Please see the attached response from Hunter Industries.
Please let me know if you have any questions or would like to follow up on any
comments.
Thank you.
KELSEY JACQUARD, CID, CLIA
Category Manager - Mechanical Irrigation Products
1 760-744-5240 Main
1 760-591-7099 Direct
Kelsev.Jacquard@hunterindustries.com
Hunter Built on Innovation
1940 Diamond Street
San Marcos, CA 92078
USA
www.hunterindustries.com
Email Attachment:
See pages 15 through 21.
EPA
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Template for Public Comment Submission on WaterSense Documents
Commenter Name: Kelsey Jacquard
Commenter Affiliation: Hunter Industries
Date of Comment Submission: March 21, 2023
Topic: Definition of spray sprinkler nozzle
Comment: Define MSMT nozzles separate from spray sprinkler nozzles.
Rationale: MSMT nozzles are established in the industry as a separate style nozzle
from "fan" spray nozzles. MSMT nozzles use multiple rotating streams to target water
distribution and to put water down slowly, more like a rotor.
ASABE 802-2020 defines a rotor as "a sprinkler that applies water in a pattern by
means of one or more rotating streams to a defined landscape area." The test
method for rotors is also different from sprays based on one or more rotating
streams.
ASABE 802-2020 defines a spray as "a sprinkler that continuously applies water in a
pattern to a defined landscape area."
ISO 8026 section 3.6 defines an irrigation sprayer as a "device that discharges water
in the form of fine jets or in a fan shape without rotational movement of its parts."
MSMT nozzles and spray nozzles are built very differently and priced differently to
the consumer. MSMT nozzles can be made of up to 20 components while a spray
nozzle is generally made up of 3-4 components. The cost to the manufacturer to
produce and ultimately to the consumer to install is about 5 times more expensive
than a spray nozzle.
Suggested Change (or Language):
Define spray nozzle as a "nozzle that discharges water in the form or fine jets or in a
fan shape without rotational movement of its parts."
Define MSMT nozzle as a "nozzle that discharges water in multiple rotating streams."
Topic: Proposed application rate as a water-efficiency criterion
Comment: Disagree with proposal of using application rate as a water-efficiency
criterion.
Rationale: The best application rate for the landscape depends on multiple factors.
Soil type, plant type, weather, water window restrictions, and available nozzle sizes
among other factors determine the best application rate for the landscape.
Sandy soils allow for high application rates from the nozzle while clay soils require
low precipitation rate nozzles to prevent runoff.
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April 26, 2023
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Hot, dry climates can prefer higher precipitation rates to better saturate the soil to
better fight evaporation where low precipitation rate nozzles would require
significantly longer runtimes to properly irrigate the landscape.
Local water districts in drought regions oftentimes limit the cycle time for each zone,
sometimes to 10 minutes for example, which is not enough time to properly irrigate
with low precipitation rate nozzles.
Smaller nozzle radius options are limited in their precipitation rate offering, where a
standard would limit the available irrigation options for certain spaces.
Low precipitation rates do prevent runoff, but irrigation efficiency comes from how
effective the applied water is to the landscape. It is possible to space heads apart to
achieve a low application rate.
CA researched the idea of using a precipitation rate requirement for the 2014
MWELO standard, and after research and stakeholder input, decided upon using DU
as the requirement for nozzle installation except on slopes which was limited to 1.0
in/hr.
More research is needed before establishing a precipitation/application rate as a
requirement or as a definition of high-efficiency irrigation. The study used measured
flow rate over published radius instead of actual radius for a true application rate
study. Ultimately, application rate can be altered based on head spacing, and DU
would have to also be a requirement to maintain a healthy landscape.
Suggested Change (or Language): Eliminate criterion.
Topic: Proposed matched precipitation as a water-efficiency criterion
Comment: Disagree with proposal of using matched precipitation rate as a water-
efficiency criterion.
Rationale: Most nozzles are already matched precipitation within their nozzle
families, but they are not always matched across families or manufacturers. A
WaterSense label for matched precipitation might be confusing and lead consumers
to believe that all these nozzles can be mixed in a landscape irrigation zone. More
research is needed before establishing matched precipitation rate as a requirement
or as a definition of high-efficiency irrigation.
Suggested Change (or Language): Eliminate criterion
Topic: Distance of throw
Comment: It is stated in the proposal that "HES sprinkler nozzles tend to have larger
distances of throw than standard sprinkler nozzles" which only applies to MSMT
nozzles.
Rationale: Other "high-efficiency" spray nozzles have the same radius range as
traditional sprays, and MSMT nozzles have a larger radius range due to the rotating
streams.
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Suggested Change (or Language): Either delete statement or correct it to "MSMT
nozzles tend to have larger distances of throw than standard spray nozzles".
Topic: Distance of throw
Comment: Request for feedback on whether HES sprinklers reduce the cost of
materials in practice would only apply to MSMT nozzles due to their longer radius
range and low precipitation rates.
Rationale: New irrigation systems designed with MSMT nozzles can have fewer
heads due to the longer radius range, and they can have more heads per zone due
to the lower flow rates. This only applies to MSMT nozzles for the radius range. For
maintenance, all nozzles on a zone would need to be replaced with HES or MSMT
nozzles if the criterion is precipitation rate. Runtimes would also need to reevaluating
to keep the landscape healthy.
Suggested Change (or Language): Eliminate this question as it does not affect
water efficiency or water savings. Also, clarify "simply replace standard sprinkler
nozzles with HES sprinkler nozzles on each zone and verify runtimes meet the
needs of the landscape".
Topic: Distance of throw as a criterion to align with reported value
Comment: Agree with proposal. The tolerance range will need to be wide enough to
reasonably accommodate variation in plastic components. A percent variation may
need to scale with the nozzle radius or use a +/- 2ft tolerance as an example. More
research is needed for an achievable tolerance.
Rationale: Variation in parts does lead to variation in radius which affects all brands
of nozzles.
Suggested Change (or Language):
Topic: ASAE S398.1 as an acceptable test method for radius of throw.
Comment: This test standard only applies to sprinklers with uniform radii. How
would the proposal apply to specialty nozzles with non-uniform radii or asymmetrical
spray patterns?
Rationale: ASAE S38.1 specifies that it only applies to sprinklers with uniform
radii. This covers testing of most Spray and MSMT nozzles using a single leg test,
but it does not include non-uniform radii or asymmetrical patterns.
From ASAE S398.1
1 Purpose
1.1 This Standard has the following three purposes:
1.1.1 To define a common test procedure for the collection of sprinkler test
data such as pressure, flow rate, and radius of throw, which may be used for
17
April 26, 2023
-------
EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
the purpose of publishing performance specifications for sprinklers whose
areas of coverage have uniform radii.
The ASABE 802 standard shows the following test method which is not clear on how
to determine the radius of throw for specialty nozzles.
TABLE 303.5.4.1
MAXIMUM COLLECTOR SPACING AND CATCHMENT
ARRANGEMENT FOR RlEGULAR SPRAY PATTERNS
WATER
DISTRIBUTION
METHOD
MAXIMUM CENTER-TO-
CENTER COLLECTOR
SPACING (FEET)
CATCHMENT
ARRANGEMENT
Spray pattern
1
Rectangular grid
Rotating stream(s)
2
Single leg
For SI: 1 foot = 30.5 cm.
Suggested Change (or Language): Either clarify the test procedure for specialty
nozzles with non-uniform radii or asymmetrical patterns or clarify the proposal to not
include specialty nozzles in this standard. "This standard applies to HES and MSMT
nozzles with uniform radii only."
Topic: DU as a criterion
Comment: More research is needed considering the lack of evidence of high DU
resulting in water savings. This is counterintuitive, and there may not be enough
controlled studies. CA Title 23 settled on a DU requirement of 65% or greater after
researching the idea of a precipitation rate requirement. A minimum DU threshold
would be the preferred requirement with no required publishing of data. If the nozzle
passes the minimum threshold, it complies.
Rationale: DU has been an established baseline for efficiency in the industry for a
long time, but the limited studies available do not show significant water savings
according to the proposal. It may be worthwhile to perform a more controlled study of
DU considering it has been accepted as the requirement in new irrigation systems in
CA.
Suggested Change (or Language): Perform more research on DU before
establishing the requirement for high-efficiency nozzles. If it looks promising,
establish a minimum DU requirement that must be reached to receive the
WaterSense label. Same as the pressure-regulated sprinkler bodies standard, create
a pass/fail criteria without publishing performance data.
Topic: DU collected as both ASABE and other test methods internally
Comment: We use both the ASABE 802-2020 test method and our own internal test
methods to measure DU.
18
April 26, 2023
-------
EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Rationale:
Suggested Change (or Language):
Topic: DU collection for specialty nozzles
Comment: The test method for DU is defined for traditional uniform radius nozzles.
Is there a test method to model the uniformity of specialty non-uniform radii nozzles
and asymmetrical pattern nozzles such as side strip and corner strip nozzles?
Rationale:
Suggested Change (or Language): Either clarify the test procedure for specialty
nozzles with non-uniform radii or asymmetrical patterns, or clarify the proposal to not
include specialty nozzles in this standard. "This standard applies to HES and MSMT
nozzles with uniform radii only."
Topic: Water droplet size
Comment: There are no established and accessible methods for testing water
droplet size. However, as precipitation rate drops for fan spray sprinklers, water
droplet sizes will decrease to apply water slowly, which makes them prone to wind
drift. If there is a way to measure precipitation rate without wind and with a controlled
wind speed, that may be an interesting way to test for water application. More
research is needed before establishing a water droplet size or wind drift effect as a
requirement or as a definition of high-efficiency irrigation.
Rationale: CIT has done research on water droplet sizes using laser optic
technology. However, that test method is no longer accessible.
Suggested Change (or Language): Eliminate water droplet criteria but research
potential test methods of uniformity and precipitation rate in wind as droplet size
does influence wind drift and misting.
Topic: List of MSMT sprinkler nozzles
Comment: Toro Precision Spray Nozzles are not MSMT nozzles.
Rationale: In the footnote c under Table 1, it is stated that the nozzles appear to
have a stream-like pattern due to oscillations in the pattern. The spray pattern does
not use streams, but instead pulses from left to right to apply water more slowly.
MSMT nozzles use multiple streams to direct water and apply water slowly to the
landscape.
Suggested Change (or Language): Eliminate the Toro Precision Spray Nozzle from
the list of MSMT nozzles.
19
April 26, 2023
-------
WaterSense
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Topic: Payback period for MSMT nozzles
Comment: Payback period should be a range depending on home size and how
nozzles are replaced.
Rationale: It could cost more than $100 to convert standard spray nozzles to MSMT
nozzles depending on whether homeowners do it themselves or hire a professional
contractor, which would be the recommended approach, especially since MSMT
nozzles adjust differently than spray nozzles.
Suggested Change (or Language): Verify the payback period if it is relevant to
nozzle efficiency. Could be longer if homeowners hire a professional contractor.
Topic: Product marking, documentation, and marketing
Comment: Product performance data and specifications are available on product
webpages and in product catalogs. Eliminate DU from this requirement.
Rationale: DU can be an evaluated pass/fail criterion for labeling but requiring
publication of DU would be confusing. Products have variation, and if they meet the
threshold required, that should be enough for the consumer.
Suggested Change (or Language): Eliminate published DU requirement for
product documentation.
Topic: Communicating savings
Comment: It is stated throughout the proposal that homeowners are likely not going
to change their runtimes when switching to a low precipitation rate nozzle. While
some may not, it is best practice to reevaluate the runtime to keep the landscape
healthy and maintain the same water application needed for the plant material.
Rationale: To maintain a healthy landscape, runtimes will have to be reevaluated or
the landscape will suffer.
Suggested Change (or Language): Eliminate language justifying water savings
from incorrect runtime scheduling or clarify that runtimes should be reevaluated with
low precipitation rate nozzles.
Topic: Calling the specification "high-efficiency" spray nozzles
Comment: There is a comment in the proposal that "high-efficiency" is not used in
marketing materials for existing products when it is already used in some product
names and marketing materials in the industry.
20
April 26, 2023
-------
EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Rationale: "High-efficiency" is used in product names and in marketing already in
the industry.
https://www.krain.com/nozzles
https://www.rainbird.com/products/he-van-hiqh-efficiencv-variable-arc-nozzles
https://www.rainbird.com/products/u-series-hiqh-efficiencv-dual-orifice-nozzles
Including their own created MWELO label for marketing.
Suggested Change (or Language): Eliminate comment if it is not relevant or retitle
nozzle standard with more detail, such as "high-uniformity nozzle".
21
April 26, 2023
-------
EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Commenter: Paul Lauenstein
Affiliation: General Public
Comment Date: March 21, 2023
Email Text:
Please ban lawn irrigation sprinklers. Lawn irrigation is a frivolous waste of our vital and
finite water resources.
See attached water bill insert entitled "Secrets of a Waterless Lawn."
Paul Lauenstein
4 Gavins Pond Rd.
Sharon, MA 02067
781-784-2986
Email Attachment:
See pages 23 through 24.
22
April 26, 2023
-------
Are you a heavy water user?
To find out how your water use
compares to the suggested maximum of
65 gallons per person per day, see the
handy lookup chart opposite.
if you use over 100,000 gallons per
year, you should get a free water audit
from Energy New England, courtesy of
the Sharon Water Department. They will
provide you with a customized analysis
that will highlight the most cost-effective
strategies for conserving water in your
home. To schedule a free water audit for
your home, call the Sharon Water
Department at 781/784-1525.
Please do your part to help our
community use water efficiently.
Sharon has a long and proud history of
protecting and preserving our drinking
water aquifers as well as the natural
beauty of our town. Read about the
sensible lawn care practices, and
efficient toilets and clothes washers
described in this pamphlet. Let's use our
municipal well water efficiently. It will
save money, improve our local
ecosystem, and maintain our water
independence.
Water Management Advisory Committee
Sharon Water Department
781/784 1525
Is your water use under 65 GPCD?
Gallons Per Capita Daily (GPCD)
NO. OF HOUSEHOLD OCCUPANTS
Sharonpv*
Water Conservation Program M
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1
2
3
4
5
6
7
8
4,000
22
11
7
5
4
4
3
3
6,000
33
16
11
8
7
5
5
4
8,000
44
22
15
11
9
7
6
5
10,000
55
27
18
14
11
9
8
7
12,000
66
33
22.
16
13
11
9
8
14,000
77
38
26
19
15
13
11
10
16,000
88
44
29
22
18
15
13
11
18,000
99
49
33
25
20
16
14
12
20,000
110
55
37
27
22
18
16
14
22,000
121
60
40
30
24
20
17
15
24,000
132
66
44
33
26
22
18
16
26,000
142
71
47
36
28
24
20
18
28,000
153
77
51
38
31
26
22
19
30,000
164
82
55
41
33
27
23
21
32,000
175
88
58
44
35
29
25
22
34,000
186
93
62
47
37
31
27
23
36,000
197
99
66
49
39
33
28
25
38,000
208
104
69
52
42
35
30
26
40,000
219
110
73
55
44
37
31
27
42,000
230
115
77
58
46
38
33
29
44,000
241
121
80
60
48
40
34
30
46,000
252
126
84
63
50
42
36
32
48,000
263
132
88
66
53
44
38
33
50,000
274
137
91
68
55
46
39
34
52,000
285
142
95
71
57
47
41
36
54,000
296
148
99
74
59
49
42
37
56,000
307
153
102
77
61
51
44
38
58,000
318
159
106
79
64
53
45
40
60,000
329
164
110
82
66
55
47
41
62,000
340
170
113
85
68
57
49
42
64,000
351
175
117
88
70
58
50
44
66,000
362
181
121
90
72
60
52
45
68,000
373
186
124
93
75
62
53
47
70,000
384
192
128
96
77
64
55
48
72,000
395
197
132
99
79
66
56
49
75,000
411
205
137
103
82
68
59
51
80,000
438
219
146
110
88
73
63
55
85,000
466
233
155
116
93
78
67
58
90,000
493
247
164
123
99
82
70
62
95,000
521
260
174
130
104
87
74
65
100,000
548
274
183
137
110
91
78
6S
23
April 26, 2023
-------
Reduce costly lawn irrigation
and still have a nice lawn
Summertime demand for water surges
almost 50% over indoor use in winter,
depleting our groundwater when it is needed
most to sustain ecosystems in local rivers,
lakes and streams. Lawn watering is the
main reason for this surge in water use.
Overwatering is expensive, and can even
cause harmful fungus outbreaks. One inch
of water per week is enough to keep a lawn
green. That includes natural rain, which
averages over 3" per month in summer.
If you can tolerate a period of dormancy
in late summer, you can have a healthy,
beautiful lawn without any irrigation at all.
The quality and thickness of the topsoil is
key. A layer of rich, organic loam 6" to 8"
thick retains moisture, encourages deep
roots, and harbors earthworms that aerate
and enrich the soil with their castings.
Topsoil can be supplemented by leaving
grass clippings and leaves shredded by your
mower to decompose on your lawn. This
builds a rich organic layer that holds
moisture and recycles the costly nutrients
you paid for when you fertilized your lawn. It
also makes lawn mowing easier! To build
topsoil faster, apply a thin layer of rich loam
or compost once or twice a year.
Applying weak organic fertilizer in spring and
fall aids moisture retention and adds
micronutrients. Mix it with equal parts of 10-
10-10 for root development, and lime to
counteract acid rain. Using white powdered
lime helps you see where you have already
fertilized. Apply this mix at a rate of about 20
lbs. per 1,000 sq. ft.
More tips for a healthy lawn:
• Cut it long. Set your mower to its highest
setting. Taller grass provides shade to
slow evaporation from the soil.
• Mow it regularly. You should be removing
less than 1/3 of the grass when you mow.
• Sharpen your mower blade. A dull blade
shreds grass instead of slicing it.
• Tolerate clover in your lawn. Clover is a
legume and adds nitrogen to the soil.
• Avoid pesticides. They kill beneficial
earthworms. If grubs become a problem,
apply milky spore. Once established in the
soil, milky spore can protect against grubs
for years!
• Overseed with drought-hardy perennial
grass seed in early September to crowd
out weeds. Apply compost, dehydrated
manure or peat moss on newly seeded
areas, especially bare spots, to hold
moisture and help establish new grass.
• Compost your own "black gold" for use
on the lawn and in your garden. Add
leaves, weeds, melon rinds, carrot peels,
tea bags, apple cores, banana peels, and
other vegetable wastes. Crushed egg
shells are good too. Avoid meat and high-
fat items like peanut butter that smell and
attract pests.
• For additional information, visit:
www.nsrwa.org/greenscapes/guidebook/
Tips and rebates for saving water
indoors:
• Get a $150 rebate for a High Efficiency
Toilet (HET) that averages under 1.28
gallons per flush (gpf). A HET saves
about 8,000 gallons per year compared
to an older 3.5 gpf model. Be sure the
dual-flush or pressure assist model you
choose is MaP rated to flush at least
500 to 1,000 grams. See:
http://www. bewaterwise. com/H ET. pdf
• Front-load clothes washers use less
water than a typical top-load washer.
They also save energy, reduce drying
time, use less detergent, cause less
fabric wear, and extend the life of your
septic system. The Water Department
offers a $200 rebate for models with an
Energy Star water factor of under 6.0
and at least 3 cu. ft. capacity ($150 for
smaller models). To look up the water
factor, see http://www.energystar.gov/
index. cfm?c=clotheswash.pr_clothes_washers
Before you buy, call the Water Dept.
at 784-1525 to confirm
which toilets and clothes washers
qualify for rebates.
• Check for leaks. Put food coloring in
your toilet tank for 15 minutes. If you
see color in the bowl, it's leaking. Also, if
your water meter advances while no one
is home, there's probably a leak.
• For more information, call the water
efficiency hotline: 1-888-772-4242.
24
April 26, 2023
-------
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Ron Wolfarth
Affiliation: Rain Bird
Comment Date: March 21, 2023
Email Text:
EPA
4
WaterSense
N/A
Email Attachment:
See pages 26 through 47.
25
April 26, 2023
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Rain^Bird.
March 21, 2023
US Environmental Protection Agency - WaterSense Program
Via Email -watersense-products@erg.com
RE: WaterSense Notice of Intent to develop a Draft Specification for Spray Sprinkler Nozzles
WaterSense Team,
Rain Bird Corporation (Rain Bird) is a leading global manufacturer and provider of irrigation
products and services headquartered in Azusa, California. The privately held company has
roots going back to 1933 during California's agricultural boom. Since the beginning, Rain Bird
has produced and offered the industry's broadest range of irrigation products for farms, golf
courses, sports arenas, commercial developments, and homes in more than 130 countries
around the world.
Over the past nine decades, Rain Bird has been awarded more than 450 patents worldwide,
including the first in 1935 for the original horizontal action impact drive sprinkler (U.S. Patent
#1,997,901), which revolutionized the food production industry and ushered in a new era in
irrigation. In fact, the original impact sprinkler was designated a historic landmark in 1990 by the
American Society of Agricultural Engineers.
Thank you for the opportunity to comment on the WaterSense Notice of Intent to develop a
specification for spray sprinkler nozzles. Rain Bird looks forward to again working
collaboratively with US Environmental Protection Agency WaterSense and other stakeholders in
advancing the WaterSense program. It fits well with Rain Bird's philosophy of efficiency we call
the Intelligent Use of Water™. Spray sprinklers are a significant user of urban residential water.
Improving their efficiency is something that Rain Bird not only supports but something in which
Rain Bird has invested heavily over its history.
Ron Wolfarth
Project Manager
(520) 907-0682
rwolfarth@rainbird.com
Rain Bird Corporation - Landscape Irrigation Division
6991 E. Southpoint Road, Tucson, AZ 85756 . Phone (520) 741-6100 . Fax (520) 741-6146
Sincerely,
26
April 26, 2023
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Rain Bird Draft Response to
US Environmental Protection Agency WaterSense Notice of Intent for
Spray Sprinkler Nozzles
Commenter Name: Ron Wolfarth, Project Manager
Commenter Affiliation: Rain Bird Corporation - Tucson, Arizona
Date of Comment Submission: March 21, 2023
Rain Bird offers a summary of its conclusions and recommendations here. These are discussed in detail
in the following response in the context of the Notice of Intent.
A. Rain Bird Conclusions
1. Appendix A savings studies do not adequately isolate the contribution made by the spray sprinkler
nozzles used in rebate programs for use in justifying the development of a draft specification for
spray sprinkler nozzles.
2. "Earlier research" (prior to the publication of the WaterSense specification for spray sprinkler
bodies) is not refuted by research subsequently published. In other words, "earlier research" is still
valid and the finding that multi-stream, multi-trajectory (MSMT) nozzles save little to no water still
stands.
3. The Wascher report should not be relied upon to cost justify the prescription of MSMT spray
sprinkler nozzles.
B. Rain Bird Recommendations
1. WaterSense should define spray sprinkler nozzle efficiency as how well a spray sprinkler nozzle
beneficially delivers water to the target landscape. Elements influencing spray sprinkler nozzle
efficiency performance, in priority order, are:
a. Manufacturer recommended operating pressure.
i. WaterSense should require WaterSense labeled spray sprinkler nozzles be installed in
combination with a WaterSense labeled spray sprinkler body with pressure regulation set to
the recommended operating pressure of the spray sprinkler nozzle. This would completely
address operating pressure elements of spray sprinkler nozzle efficiency.
ii. WaterSense should abandon the notion that MSMT spray sprinkler nozzles are more
efficient because when operated well above the manufacturer recommended operating
pressure their flow increases proportionally less than fan spray sprinkler nozzles which are
also operated well above the manufacturer recommended operating pressure.
b. Water droplet size
i. WaterSense should consider water droplet size distribution of spray sprinkler nozzles as an
element of spray sprinkler nozzle efficiency. A water droplet size distribution biased toward
larger sized droplets potentially has the following potential beneficial effects.
1. Less wind drift losses.
2. Less evaporation losses.
3. Longer radius of throw,
a. Distribution Uniformity
i. WaterSense should require that spray sprinkler nozzles have distribution uniformity of 65%
or higher.
27
April 26, 2023
-------
ii. This 65% value matches the value set in California's Model Water Efficient Landscape
Ordinance.
iii. Research performed by Dr. Michael Dukes shows that investments in achieving distribution
uniformity higher than 50% contribute diminishing improvements to soil moisture
uniformity.
b. Matched precipitation rate
i. WaterSense should require labeled spray sprinkler nozzles to have matched precipitation
rate among all members of a product family that a user would normally combine on a single
zone of an irrigation system.
ii. WaterSense should use theoretical precipitation rate and allow a maximum of 20%
variability between any two members of a product family that would normally be combined
on the same zone valve to determine whether a set of nozzles is matched precipitation rate.
iii. All patterns and radius sets of a spray sprinkler nozzle product family should be required to
be matched precipitation rate for the product family to qualify for the label.
iv. Precipitation rate should vary no more than 20% between any two members of the same
product family which users would normally combine on the same zone valve.
2. WaterSense should not categorize spray sprinkler nozzles as HES and Standard in the draft
specification.
a. The assignment of certain products to the categories of HES and Standard should not be done
before the definition of spray sprinkler nozzle efficiency and a testing protocol is agreed upon
and testing of spray sprinkler nozzles is complete. Only then will it be known which products
belong to each category.
3. WaterSense should not use application rate as a criterion for the WaterSense draft specification for
spray sprinkler nozzles.
a. The application rate of spray sprinkler nozzles is not relevant to the efficiency of nozzles.
Proponents of using application rate in this context cite runoff as the problem that is addressed.
Runoff is a management issue that should be addressed by the proper management of irrigation
schedules aided by WaterSense labeled weather-based controllers.
4. WaterSense should not use the flow rate of spray sprinkler nozzles as an efficiency criterion.
5. WaterSense should abandon the notion that MSMT spray sprinkler nozzles have a pressure
regulating effect because they have lower flow rates when operated much higher than the
manufacturer recommended operating pressure.
6. WaterSense should not set a radius "exceedance" threshold.
a. "Exceedance" is not defined or included in the ASABE S398.1 standard for determining sprinkler
radius and no other known standard includes this term or concept.
b. There is no practical technology available to more tightly control the distance a nozzle throws
water beyond its S398.1 defined radius.
c. The amount of water that is sprayed beyond the S398.1 defined radius is not material in zero
wind conditions.
7. Stakeholders should endeavor to develop an American National Standards Institute (ANSI) standard
that defines spray sprinkler nozzle efficiency and a spray sprinkler nozzle testing protocol.
a. Consensus agreement on the definition of spray sprinkler nozzle efficiency and a testing
protocol that quantifies performance in those areas is needed to clearly distinguish efficient
products from inefficient products.
8. Stakeholders should endeavor to develop a coefficient which describes the relationship between
water loss due to wind drift and evaporation under different operating pressures and wind speeds
and water droplet size distribution of spray sprinkler nozzles.
28
April 26, 2023
-------
a. A coefficient of this sort would allow indoor testing of spray sprinkler nozzles to determine wind
drift and evaporation efficiency of those nozzles.
9. WaterSense should not rely on Appendix A studies to determine if the use of MSMT spray sprinkler
nozzle result in water savings.
a. While the studies do show that programs which rebate the retrofit of spray sprinkler nozzles can
result in lower water use, they do not adequately isolate the contribution that the spray
sprinkler nozzle made to the savings.
10. WaterSense should suspend its development of the draft specification for spray sprinkler nozzles
until such time as the proposed standards are published.
11. Once the proposed standard and coefficient exist and testing of spray sprinkler nozzles is complete,
WaterSense should resume development of the draft specification for spray sprinkler nozzles.
a. Test results will reveal spray sprinkler nozzle efficiency performance.
b. WaterSense should use these test results to set performance thresholds to qualify for the
WaterSense label.
Responses to Questions in and Comments on the WaterSense Notice of Intent
C. Technical Background Section (starting on page 2)
1. Topic: "WaterSense would like stakeholder input on its product category definition of "spray
sprinkler nozzle"." (From the Technical Background section on page 5)
Response: Rain Bird supports this definition.
Rationale: No further comment.
D. Scope Section (Starting on page5)
1. Topic: "WaterSense would like stakeholder feedback on the intended scope of the specification."
(From the Scope section on page 7)
Response: If product categories must be assigned in the draft specification, they should be called "Fan
Spray Sprinkler Nozzle" and "Multi-Stream, Multi-Trajectory (MSMT) Spray Sprinkler Nozzle".
Rationale: WaterSense should not categorize spray sprinkler nozzles in the draft specification. Certainly,
WaterSense should not categorize the products in a prescriptive way according to product features like
application rate or multiple streams and multiple trajectories. If consensus was reached on the
definition of spray sprinkler nozzle efficiency and a testing protocol which revealed each spray sprinkler
nozzle's performance against that standard, WaterSense could then set an efficiency performance
threshold for WaterSense label qualification. Spray sprinkler nozzles would be categorized as
WaterSense labeled (HES) and non-WaterSense labeled (Standard) spray sprinkler nozzles.
Comment: The use of the category name "Standard" in the Notice of Intent implies that those are the
inefficient spray sprinkler nozzles when compared to the MSMT, or High Efficiency Spray Sprinkler (HES)
nozzles. Rain Bird does not believe this to be a uniformly true characterization of fan spray sprinkler
nozzles. Some fan spray sprinkler nozzles are highly efficient. Including these high efficiency fan spray
sprinkler nozzles in a category called "Standard" when Standard is then used to describe everything
other than high efficiency products (implying low efficiency products) is not accurate.
If WaterSense must categorize spray sprinkler nozzles in some way and desires to use the word
"Standard" to refer to products that are not high efficiency compared to other products which are high
efficiency, then it should categorize and name the products as:
29
April 26, 2023
-------
High Efficiency Fan Spray Sprinkler Nozzles
Standard Fan Spray Sprinkler Nozzles
High Efficiency MSMT Spray Sprinkler Nozzles
Standard MSMT Spray Sprinkler Nozzles
Perhaps there are no members of the High Efficiency Fan Spray Sprinkler Nozzles and Standard MSMT
Spray Sprinkler Nozzles categories. However, that will not be known until consensus is reached on the
definition of Spray Sprinkler Nozzle Efficiency, a Testing protocol is defined, and testing is completed.
E. Water Efficiency and Performance Section (starting on page 7)
1. Topic: "As described in Section VII Estimated Water Savings, WaterSense has estimated that some
types of spray sprinkler nozzles use approximately 10 percent less water than standard spray
sprinkler nozzles. WaterSense has found that spray sprinkler nozzles marketed as "high-efficiency"
are MSMT nozzles that emit multiple streams of water at multiple trajectories. Based on
WaterSense's research, water utilities with rebate programs for spray sprinkler nozzles often require
MSMT nozzles. Furthermore, although the authors used a variety of terms for the product, MSMT
nozzles were considered a more water-efficient option in the water savings studies documented in
Appendix A." (From the first paragraph of the Water Efficiency and Performance section on page 7)
Comment:
a. The conclusion that "some types" of spray sprinkler nozzles (presumably MSMT) use
approximately 10 percent less water than "Standard" spray sprinkler nozzles (presumably
everything else) is based on the savings studies in Appendix A which was not yet published in
2017 when the WaterSense Spray Sprinkler Body Specification was published. WaterSense
excluded Spray Sprinkler Nozzles from its 2017 Spray Sprinkler Body Specification because it
concluded that there was no research which supported any spray sprinkler nozzle as more
efficient than other spray sprinkler nozzles. In fact, that research showed MSMT spray sprinkler
nozzles were not more efficient than other spray sprinkler nozzles. MSMT spray sprinkler
nozzles showed little or no savings.
It appears that since Appendix A savings studies primarily studied MSMT spray sprinkler nozzles
and savings were claimed, WaterSense has chosen to exclude all other spray sprinkler nozzles on
the market, even those that are marketed as high efficiency spray sprinkler nozzles. Rain Bird
believes this to be a wrong conclusion for several reasons.
ii. It is not clear that Appendix A savings studies considered other high efficiency fan spray
sprinkler nozzles. Two examples are the Rain Bird HE-VAN (High Efficiency Variable Arc
Nozzle) and the Rain Bird U-Series (Undercut) spray sprinkler nozzles. Both products are
more efficient than others on the market. Rain Bird competitors also offer spray sprinkler
nozzles marketed as being high efficiency.
iii. It is not practical to give a detailed analysis of each of the Appendix A savings studies in
these comments. However, Rain Bird finds, in general, that the WaterSense conclusion
that MSMT spray sprinkler nozzles use 10% less water is not warranted.
1. At least some of the savings studies were initiated after the conservation programs
were complete. Therefore, there was no opportunity for those conducting the studies
to control or know many relevant variables.
2. Valid assessments in those cases were reached that the implementation of the
conservation program resulted in less water being used by the conservation program
participants, because water use records exist before and after the retrofits were
conducted. Rain Bird accepts the conclusion that less water was used after the retrofit
compared to the period before the retrofit.
3. However, many elements may have contributed to those savings. Because those other
elements were not able to be controlled by those conducting the study, the degree to
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which MSMT spray sprinkler nozzles contributed to water use reduction cannot be
determined. It may have been a positive or negative contribution or no contribution at
all as was determined in some of the earlier research.
4. As an example, Rain Bird believes that proper irrigation scheduling plays a very
important role in efficient irrigation. If users were told that the nozzles they were
given are more efficient because they have lower application rates, some, maybe most,
users would be triggered to adjust their irrigation schedule. Perhaps they were
encouraged to adjust their irrigation schedules by program sponsors. It is very possible
that the schedule on the controller prior to the retrofit was very inefficient. The
correction of the irrigation schedule could account for all the savings caused by the
replacement program even if the nozzles had not been retrofitted,
iv. Many of the Appendix A studies raise questions that cause Rain Bird to be cautious in
drawing conclusions regarding reduced water use directly attributable to MSMT spray
sprinkler nozzles.
a. Many stakeholders assume all fan spray sprinkler nozzles are inefficient because most
have higher application rates compared to MSMT spray sprinkler nozzles. Runoff is
widely and appropriately viewed as waste and something to be avoided. Rain Bird
agrees. Runoff is caused by poor management of the irrigation system. It is not an
inherent characteristic of spray sprinkler nozzles. Application/precipitation rate should
not be a criterion for defining spray sprinkler nozzle efficiency or for WaterSense
labeling.
v. Consider hypothetically if a spray sprinkler nozzle A were to be developed with an
application rate typical of fan spray sprinkler nozzles and was shown to apply 90% of total
irrigation water to the target landscape area in a normal wind condition. Consider also
spray sprinkler nozzle B that had application rates typical of MSMT spray sprinkler nozzles
and were shown to apply only 80% of total irrigation water to the target landscape area in
the same wind condition. Spray sprinkler nozzle A and B have similar distribution
uniformity. (The lower amount of water reaching the target area of spray sprinkler nozzle
B could be due to losses from wind drift and evaporation.)
1. Spray sprinkler nozzle A should not be excluded from receiving a WaterSense label
due to its higher application rate when a much higher portion of water delivered
through the irrigation system is made beneficially available to the crop. Spray
sprinkler nozzle A is more efficient.
2. The only reason spray sprinkler nozzle A might not deliver more beneficial water to
the crop than spray sprinkler nozzle B in this hypothetical case would be due to
misuse causing runoff. Mismanagement of the irrigation schedule is the true cause
of the waste in this hypothetical case, not the spray sprinkler nozzle.
3. Application/precipitation rate should not be a criterion for a WaterSense label.
vi. A common user response to observing runoff or its effects is to adjust the irrigation
schedule. (Many users either do not observe the runoff or ignore this waste signal.)
vii. If spray sprinkler nozzle application rates were somehow able to be matched to the
infiltration rate of the soil, all runoff would be eliminated and no waste signal would be
visible to the user, the community or a policing authority. However, if the scheduling of
the irrigation system is still set to over-irrigate, the excess irrigation would percolate
beyond the root zone and be wasted. It would also be invisible. Those users may conclude
that since there is no runoff, there is no waste and this is the cost of maintaining an
attractive landscape. They would have no reason to be embarrassed by their irrigation
habits.
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2. Topic: "It is possible that manufacturers could develop other types of high-efficiency spray sprinkler
nozzles in the future. To be inclusive of future developments in the market, WaterSense uses the
phrase high-efficiency spray (HES) sprinkler nozzle' (which includes MSMT nozzles) in this NOI to
differentiate the products that WaterSense is considering labeling." (From the second paragraph of
the Water Efficiency and Performance section on page 7)
Comment:
a. Rain Bird does not support this.
b. The quoted phrase in parenthesis, "(which includes MSMT nozzles)/' currently seems to exclude
everything else currently on the market and only leaves open the possibility of "other types of
high-efficiency spray sprinkler nozzles in the future". The exclusion of other existing products
from Rain Bird and its competitors that are marketed as high efficiency from the HES category is
inappropriate without data that supports that decision.
c. Rain Bird believes that WaterSense should pause its development of a draft specification for
spray sprinkler nozzles until an ANSI standard definition of Spray Sprinkler Nozzle Efficiency and
a standard Testing Protocol is developed and published. WaterSense should resume
development of the draft specification when efficiency testing of spray sprinkler nozzles
according to the new standard is complete.
F. Application Rate Section (starting on page 8)
1. Topic: "Pressure regulation can also directly and independently affect application rate. Pressure
regulating spray sprinkler bodies create a constant flow rate to the sprinkler nozzle regardless of
supply pressure. Without pressure regulation, spray sprinkler bodies may apply water at higher rates
than the sprinkler nozzle's specified application rate". (From the end of the last paragraph on page 8)
Comment:
a. RE: "Pressure regulating sprinkler bodies create a constant flow rate to the sprinkler nozzle
regardless of supply pressure."
This is not an accurate statement. Pressure regulators provide a relatively constant downstream
pressure when upstream pressure and flow rate fluctuates within a range. Spray sprinkler
nozzles of different nominal flow rates can be installed on the same pressure regulated spray
sprinkler body and the pressure supplied to the nozzle remains about the same while the
nozzles will flow at different rates.
b. Given the recognized importance of spray sprinkler body pressure regulation (indicated by the
WaterSense Spray Sprinkler Body label specification), the spray sprinkler nozzle label
specification should require the combination of WaterSense label sprinkler spray bodies and
spray sprinkler nozzles. The WaterSense Irrigation Controller specification requires the
combination of multiple products in order qualify for the label. This will ensure proper
operating pressure and will improve irrigation efficiency.
2. Topic: "...preliminary research results suggest that HES sprinkler spray nozzles provide a similar
effect as pressure regulation, though likely not to the same extent as pressure-regulating sprinkler
bodies." (From paragraph 1 on page 9)
Comment:
a. Pressure regulators provide a relatively constant downstream pressure when upstream pressure
and flow rate fluctuates within a range. Suggesting that MSMT nozzles have a similar effect as
pressure regulation is misleading to the uninformed reader by suggesting that this is a positive
characteristic of MSMT nozzles.
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b. It is accurate to say that as pressure increases above the recommended operating pressure of
MSMT nozzles, flow rate rises less than fan spray nozzles rise under those conditions.
However, it is very instructive to also say that water droplet size is reduced as pressure rises.
The higher the water pressure applied to the nozzle orifice, the greater proportion of small
water droplets that are generated. A nozzle with a small orifice will generate more smaller
water droplets compared a larger nozzle operated at the same high pressure. (This is how
misting systems used for cooling in outdoor, desert environments work. Nozzles with very small
orifices at very high pressure atomize the water which very quickly evaporates absorbing the
heat energy which cools the air.)
c. As operating pressures rise, water droplets become smaller and more subject to wind drift and
evaporation causing irrigation water losses. This informs the reader regarding the potentially
negative aspects of operating spray sprinkler nozzles with smaller orifices at high operating
pressures. The degree to which this is true for MSMT or fan spray sprinkler nozzles can only be
determined by testing.
3. Topic: "WaterSense is not aware of a Test Method for evaluating matched precipitation rate or
pressure regulation provided by spray sprinkler nozzles". (From paragraph 2 under 'Testing Methods
and Associated Data' on page 9)
Comment:
a. Theoretical application rate evaluation does not require testing. WaterSense should use
theoretical application rate to evaluate matched precipitation rate.
b. Theoretical precipitation rate can be calculated for each nozzle of different arcs and radii based
on published data from the manufacturer. When nozzles are combined on a zone of an
irrigation system with spacing and arrangement that results in the same precipitation rate, it is
considered "matched". If a test plot of unmatched precipitation rate nozzles were operated and
catch cans collected the water, it would theoretically have poorer uniformity than a test plot of
matched precipitation rate nozzles. What is not known is how much of the water that leaves
the spray sprinkler nozzle hits the ground instead of evaporating or blowing away.
c. Net application rate is determined using a grid of catch cans. It uses the average amount of
water captured in catch cans in a formula to determine the depth of water that reaches the
surface of the ground over a given period. It accounts for some losses, primarily wind drift and
evaporation especially if it is conducted outdoors. Using net application rate would require a
large amount of testing. This testing provides little value to the evaluation of matched
precipitation rate. It may have value in the overall efficiency evaluation of a nozzle because it
takes wind drift and evaporation into account if the testing is conducted outdoors under wind
controlled and/or measured conditions.
d. There is currently no test method for evaluating pressure regulation of spray sprinkler nozzles
because no spray sprinkler nozzles currently have pressure regulation features. Perhaps this
feature will be offered in the marketplace in the future. Pressure regulation of spray sprinklers
is currently only available in the spray sprinkler body.
e. A benefit of pressure regulation devices integral to the spray sprinkler bodies is that
downstream operating pressure is the same regardless of the flow of the spray sprinkler nozzle.
Spray sprinkler nozzles of differing flow rates can be installed on the same sprinkler spray body
and operating water pressure at the spray sprinkler nozzle remains about the same.
f. Water droplet size distribution of a nozzle is determined by several factors. Some of these
factors are:
i. Nozzle orifice size,
ii. Nozzle shape,
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iii. Pressure at the nozzle,
iv. Turbulence in the flow path of water to the nozzle, and
v. Coefficient of friction in the water path to the nozzle.
A combination of these, and other, factors determine the water droplet size distribution of a
nozzle. There exists a wide range of variability in water droplet size distribution results. This
wide range of results significantly impact how much irrigation water is made beneficially
available to the crop.
g. Smaller water droplets weigh less than the larger water droplets. At some point of higher
operating pressure, more of the water droplets become small and light and they do not travel as
far (in addition to being blown away in a breeze and/or evaporating before reaching the
ground). This causes poor irrigation coverage, poor performance of the crop, and is the
definition of inefficient irrigation. Spray sprinkler nozzles should never be operated beyond the
manufacturer's recommended operating pressure. WaterSense should require the use of
WaterSense labeled spray sprinkler bodiesjn combination with qualifying spray sprinkler nozzles
to qualify for the WaterSense label.
h. WaterSense should not consider one type of spray sprinkler nozzle more efficient than another
because when one is operated beyond the manufacturer's recommended operating range, it
results in less flow than another type of spray sprinkler nozzle also operating beyond the
recommended operating range.
4. Topic: "As discussed in Section V Existing Performance Data, Dr. Michael Dukes of the University of
Florida conducted research to evaluate whether spray sprinkler nozzles could be differentiated based
onflow rate. Dr. Dukes developed a test method that aligns with ASABE/ICC 802-2020. His results
indicate that flow rate is substantially lower in HES sprinkler nozzles compared to their standard
counterparts. Based on these findings, ASABE/ICC 802-2020 could be used to differentiate spray
sprinkler nozzles. The application rate can be calculated from flow rate by measuring irrigated area
and using Equation 3-1 in ASABE/ICC802-2020, which aligns with Equation 1 above." (From
paragraph 3 under 'Testing Methods and Associated Data' on page 9)
Comment:
a. A review of published manufacturer literature reveals the same finding that MSMT spray
sprinkler nozzles have lower flow rates than most fan spray sprinkler nozzles.
b. Nozzle flow rate is not an element of irrigation efficiency and should not be used as such.
Topic: "flow rate is substantially lower in HES sprinkler nozzles compared to their standard
counterparts..." (From paragraph 3 under 'Testing Methods and Associated Data' on page 9)
Comment:
a. Nozzle flow rate is not an element of irrigation efficiency and should not be used as such.
b. The use of the category name "Standard" in the Notice of Intent implies that those are the
inefficient spray sprinkler nozzles when compared to the MSMT, or High Efficiency Spray
Sprinkler (HES) nozzles. Rain Bird does not believe this to be a uniformly true characterization of
fan spray sprinkler nozzles. Some fan spray sprinkler nozzles are high efficiency. Including these
high efficiency fan spray sprinkler nozzles in a category called "Standard" when Standard is then
used to describe everything other than high efficiency products (implying low efficiency
products) is not accurate.
c. If WaterSense desires to use the word Standard to refer to products that are not high efficiency
compared to other products which are high efficiency, then it should categorize the products as:
High Efficiency Fan Spray Sprinkler Nozzles
Standard Fan Spray Sprinkler Nozzles
High Efficiency MSMT Spray Sprinkler Nozzles
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Standard MSMT Spray Sprinkler Nozzles
Perhaps there are no members of the High Efficiency Fan Spray Sprinkler Nozzles and Standard
MSMT Spray Sprinkler Nozzles categories. However, that will not be known by WaterSense until
consensus is reached on the definition of Spray Sprinkler Nozzle Efficiency and a Testing
protocol is defined and testing is completed.
5. Topic: "WaterSense is considering using application rate as a water efficiency criterion to identify
HES sprinkler nozzles. For a spray sprinkler nozzle to earn the WaterSense label, WaterSense would
propose two thresholds for application rates: one at the manufacturer's recommended operating
pressure and one at high pressure. WaterSense would set the thresholds based on Dr. Dukes' data
and reference the test method in ASABE/ICC 802-2020.
For the purposes of this NOI, WaterSense is proposing that each radius in a model's product family
be tested (for example, 12- and 15-feet radii versions of a model) at the full circle pattern only. If the
nozzle has an adjustable radius, WaterSense is considering requiring it to be tested at the maximum
radius.
For the purposes of this NOI, WaterSense is proposing that each radius in a model's product family
be tested (for example, 12- and 15-feet radii versions of a model) at the full circle pattern only. If the
nozzle has an adjustable radius, WaterSense is considering requiring it to be tested at the maximum
radius.
WaterSense is seeking stakeholder feedback on its proposal to use application rate (at
recommended operating pressure and high pressure) as a water efficiency criterion for spray
sprinkler nozzles. WaterSense is also interested in whether any manufacturers currently use the
ASABE/ICC 802-2020 test method for application rate and, if so, would be willing to share masked
data with WaterSense.
Additionally, WaterSense requests stakeholder opinions on using the following parameters to
evaluate spray sprinkler nozzles:
Test each radius in a model's product family at the full circle pattern only; and
Test models with an adjustable radius at the maximum radius." (From the Application Rate as
Water Efficiency or Performance Criteria section starting on in the middle of page 9 and ending
on page 10)
Response: RE: "WaterSense is considering using application rate as a water efficiency criterion to
identify HES sprinkler nozzles."
Application/precipitation rate should not be a criterion for a WaterSense label.
Rationale: Lowering application/precipitation rates of sprinklers is an attempt to reduce runoff. Runoff
is a failure of irrigation scheduling and is neither an inherent characteristic of spray sprinkler nozzles nor
an element of irrigation efficiency.
Response: RE: "(at recommended operating pressure and high pressure)".
Rain Bird is concerned that the publication (by Rain Bird or by its release to WaterSense) of product
performance data outside of the recommended operating pressure will confuse and mislead customers.
Rain Bird is very hesitant to participate in the sharing of data which constitutes misuse of the product.
Rationale: Users should never operate spray sprinkler nozzles at pressures beyond the manufacturer's
recommended operating pressure. WaterSense would confuse some users if it were to say that one
spray sprinkler nozzle is better than another because it uses less water than another when it also is
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operated at 'high' pressure. Some users may conclude that WaterSense believes that it is acceptable to
operate the HES at those high pressures, but not the 'Standard' spray sprinkler nozzles.
Rationale: Rain Bird's decades-long, customary practice when presenting Rain Bird landscape irrigation
product performance data in printed form has been to only provide to customers that data collected
under conditions at which Rain Bird recommends the use of the product. Customers have become
accustomed to that practice. When they see printed Rain Bird landscape irrigation performance data,
they know that Rain Bird recommends the product's use under those conditions. There is no other
indication in Rain Bird landscape irrigation product literature of recommended use conditions.
Response: RE: "application rate as a water efficiency criterion."
Application/precipitation rate is not an element of spray sprinkler nozzle efficiency and should not be a
criterion for a WaterSense label.
Rationale: Rain Bird does not support application rate as a water efficiency criterion for the several
reasons.
a. A lower application/precipitation rate can reduce and/or delay the start of runoff. However,
runoff can only occur when the irrigation schedule is mismanaged. It has been said, "If a
perfectly designed, installed and maintained irrigation system is mismanaged, then water will
simply be wasted more efficiently than ever before". Irrigation schedule management is the
cause of the runoff problem. That problem is best addressed by WaterSense labeled irrigation
controllers and user education.
b. Runoff is a waste signal and may trigger some users to address that waste by addressing the
poor irrigation schedule management.
c. If an irrigation schedule set to over-irrigate is not addressed and runoff is otherwise eliminated,
water will percolate past the reach of the crop's roots (commonly called 'deep percolation') and
be wasted the same as if it were to runoff.
Comment: There exists a point of view that lower application/precipitation rates can lead to lower
irrigation efficiency, especially in a residential application.
a. Lower application/precipitation rates will extend the time needed to irrigate properly. This
could possibly expose the sprinklers to less favorable wind conditions and increase the time
water is suspended in the air subjecting it to more wind drift and evaporation and increase
those losses.
b. Lower application/precipitation rate zones require less flow to cover the same area of
landscape. The size in area (square feet) of many residential landscape hydrozones are driven
by the different plant water needs. These water needs differ due to plant type, sun/shade
exposure, drainage patterns, and soil type variations. Residential contractors are subject to cost
competition. Respecting these hydrozone requirements requires more zones so they can be
scheduled differently in run time and irrigation interval. More hydrozones require more zone
valves. Cost driven contractors are tempted to ignore these hydrozone requirements in favor of
a lower installation cost so that they will have a lower sale price to the homeowner compared to
their efficiency-driven contractor competitor.
c. This cost difference driver is demonstrated in the John Wascher (Hunter Industries) report cited
in Appendix A of the Notice of Intent. For Wascher to show a lower installation cost in his
MSMT spray sprinkler nozzle design compared to the fan spray sprinkler nozzle design, Wascher
had to assume:
i. The landscape was 100% turf.
ii. Sun/shade patterns ("micro-climate differences"?) were not relevant.
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iii. The site was entirely flat.
iv. Some of the landscape did not have to be irrigated.
v. Overspray onto neighboring property was acceptable.
vi. The poor uniformity of a single row of sprinklers was acceptable.
vii. A single row of sprinklers on the same zone as sprinklers spaced head-to-head
resulting in very different application rates was acceptable.
These are neither the conditions of the "typical" residential landscape, nor are these tradeoffs
that enhance irrigation efficiency. These are bad design choices driven by a desire for a lower
installation cost.
d. The lower the precipitation rate of the spray sprinkler in a residential setting, the higher the
temptation to compromise good, efficient irrigation design principles due to the potential cost
savings of those tradeoffs.
e. One reason the higher flow rate of fan spray sprinkler nozzles result in more zone valves is
because they more quickly exceed the capacity of the residential water supply source. This
tends to negate the temptation to make poor irrigation system design tradeoffs that entice the
cost driven contractor. It also makes a more even cost playing field for the efficiency driven
contractor who installs more zone valves.
f. Application/precipitation rate is not an element of spray sprinkler nozzle efficiency and should
not be a criterion for a WaterSense label.
Response: RE: Use of ASABE/ICC 802-2020 for the calculation of Application Rate and the sharing of
masked data.
Rain Bird uses equation 3-1 in ASABE/ICC 802-2020 to calculate Application/Precipitation Rate and
publishes those results in its literature.
Rationale: No further comment.
Response: RE: Testing of spray sprinkler nozzles of differing radii at full circle only.
Rain Bird supports the testing of spray sprinkler nozzles of differing radii at full circle only if testing must
be done.
Comment: Application/precipitation rate is not an element of spray sprinkler nozzle efficiency and
should not be a criterion for a WaterSense label.
Response: RE: Test models with an adjustable radius at the maximum radius.
Rain Bird supports the testing of models with an adjustable radius at the maximum radius .
Rationale: No further comment.
Response: If WaterSense tests spray sprinkler nozzles which have an adjustable arc, they should be
tested at full radius and full arc.
Rationale: No further comment.
6. Topic: "Although spray sprinkler nozzles are not necessarily pressure-regulating by design, Dr. Dukes'
results provide some evidence that MSMT nozzles may provide a similar effect as pressure
regulation. (See Section V Existing Performance Data for more details.) As a result, WaterSense
would not need to include a separate test method for pressure regulation but would incorporate it
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into the evaluation of application rate." (From the Application Rate as Water Efficiency or
Performance Criteria section second full paragraph of page 10)
Comment:
While Dr. Duke's results are interesting, WaterSense should not use this information to prescriptively
require MSMT spray sprinkler nozzles to qualify for a WaterSense label.
a. WaterSense should require the use of WaterSense labeled spray sprinkler bodies_regulated at
the manufacturer's recommended operating pressure in combination with qualifying spray
sprinkler nozzles to qualify for the WaterSense label. No study or testing would then be
required.
b. WaterSense labeled Irrigation Controllers require several products which are sold separately to
be combined to qualify for the WaterSense label.
7. Topic: "To evaluate matched precipitation, WaterSense is proposing that licensed certifying bodies
evaluate application rates across an entire family of models. WaterSense is not aware of an industry
standard variance in application rates that constitutes matched precipitation for spray sprinkler
nozzles. WaterSense would need to identify an acceptable variance for the purposes of the
specification.
WaterSense seeks input on whether it should require spray sprinkler nozzles to have matched
precipitation to be eligible for the WaterSense label. What would be an acceptable variance in
application rates to ensure matched precipitation? If WaterSense requires matched precipitation,
how should EPA verify the data?" (From the Application Rate as Water Efficiency or Performance
Criteria section third full paragraph of page 10)
Response: RE: MPR requirement for eligibility for WaterSense label.
Yes, theoretical MPR should be required for a WaterSense label.
Rationale: Theoretical matched precipitation rate (MPR) is a critical aspect of spray sprinkler nozzles in
providing uniform application of water in a properly designed, installed, maintained and managed
irrigation system. The MPR requirement should include not only MPR between all arcs (quarter, half,
full circle, as examples) of a nozzle family, but also between the different radii offered within that nozzle
family. WaterSense should not allow an exception to models of the same nozzle family. If one radius
model of the family does not conform to the MPR criteria, the entire family should not be eligible for
labeling. Rain Bird believes that allowing such exceptions would be too confusing and misleading to the
consumer. It may result in models of the family with mis-matched precipitation rates combined on the
same zone. That would result in poor uniformity across that zone of the irrigation system and waste
water.
Response: RE: Acceptable variance in MPR for WaterSense label eligibility.
Rain Bird recommends no greater than 20% variability in theoretical MPR between arcs of nozzles and
radius sets of nozzles to be eligible for a WaterSense label.
Rationale: Rain Bird strives for perfection in this area, but there are limits to what can be accomplished
in the design and manufacturing processes. A requirement of variability less than 20% may not be able
to be achieved.
Response: RE: EPA verification of data.
WaterSense could consult published data which the manufacturer would self-certify.
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Rationale: Spot checks of published manufacturer self-certified data is adequate to confirm
conformance.
G. Distance of Throw Section (starting on page 10)
1. Topic: "WaterSense is interested in feedback from irrigation contractors about whether they are
likely to incorporate HES sprinkler nozzles in bids for new irrigation systems, any factors that
might influence their decision (i.e., new installation vs. retrofit), and whether HES sprinklers
reduce the cost of materials in practice." (From the Distance of Throw section on pages 10 and 11)
Response: Contractors currently incorporate MSMT nozzles in new and retrofit applications. MSMT
nozzles may reduce the cost of materials (and labor) in practice in some situations.
Rationale: An element missing from the NOI discussion of sprinkler spray nozzle radius of throw is that
of performance and adherence to efficient irrigation design practices.
There are irrigation design cost tradeoffs that harm irrigation efficiency and there is insufficient
information given in the Waschler report (John Waschler, Hunter Industries). Some missing data and
questionable efficient design tradeoffs are:
a. The study assumes 100% turf (which reduces the need for hydrozoning for different plant water
requirements and allows fewer valves, larger radius sprinklers to be used and reduces the need
for small radius spray sprinkler nozzles which reduced the cost of the MSMT design. The report
then claims it is a typical landscape which is, at best, a questionable claim),
b. Microzones and climate are not considered (which reduces the need for more valves due to
exposure (sun/shade) differences and the subsequent radius reduction necessary),
c. No irrigation legend (to determine the radius of the nozzle which then allows determination of
the existence of over/underspray),
d. Questionable layout of zone valves in the fan spray sprinkler nozzle design (For example, in the
fan spray sprinkler design, the zone on the left side of the house is supplied by a zone valve on
the right side of the house. The zone valve could be located directly adjacent to the zone it
serves. About 100 feet of lateral line is wasted.)
e. Overspray onto adjacent property is tolerated on the MSMT design which reduces expense and
may violate building codes in some jurisdictions.
f. Single row irrigation is tolerated which reduces expense for the MSMT design more than for the
fan spray design and significantly degrades distribution uniformity.
g. A single row of sprinklers on the same zone as sprinklers spaced head-to-head resulting in
precipitation rates which are not matched is acceptable.
h. Grading plan to determine slope vs flat areas and drainage patterns and the potential need for
more hydrozones.
i. Some of the landscape area is not irrigated. The tree near the front door does not seem to be
irrigated which would add another zone valve to the MSMT design and likely not add a zone
valve on the fan spray design.
The conclusion that MSMT nozzles lower installation cost on this site is not warranted unless efficient
irrigation design principles are ignored.
Rain Bird believes that there is potential for MSMT nozzles to reduce installation cost and to not
compromise design integrity in certain circumstances. This will often not be the case. A more
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comprehensive study of a diversity of landscapes is needed to cost justify the WaterSense prescription
of MSMT spray sprinkler nozzles.
There are many applications where there would be no cost savings with MSMT nozzles. Given the
higher unit cost of MSMT nozzles compared to fan spray sprinkler nozzles, MSMT nozzles may increase
the installation cost on sites that would require the same number of fan spray sprinklers as MSMT spray
sprinkler nozzles due to the design elements discussed above.
Some states have enacted legislation requiring that only spray sprinkler bodies that are WaterSense
labeled be sold and/or installed in that state. Rain Bird expects a similar legislative response to
WaterSense labeled spray sprinkler nozzles. This would require MSMT spray sprinkler nozzles in all
circumstances where a spray sprinkler nozzle is the best choice and would severely limit irrigation
designers.
Landscapes which have small-sized irrigation hydrozones due to lot size and/or diverse hydrozone
requirements are highly likely to require the same number of spray sprinkler bodies regardless of which
style (fan or MSMT) nozzle is chosen. In those cases, the use of MSMT nozzles could increase the
installation expense.
2. Topic: "WaterSense seeks stakeholder feedback on whether ASAE/ASABE S398.1 is an appropriate
test method for distance of throw.
Do stakeholders believe it is reasonable for WaterSense to require the tested distance of throw to
align with the value reported by the manufacturer? WaterSense is also interested in stakeholder
input on the appropriate percent exceedance (e.g., percentage greater than the rated distance of
throw) to prevent water waste due to overspray." (From the Distance of Throw as Water Efficiency
or Performance Criteria section on page 12)
Response: RE: Appropriateness of ASAE/ASABE S398.1.
Yes, ASAE/ASABE S398.1 is appropriate to use to determine distance of throw.
Rationale: S398.1 is one of few existing standards in the irrigation industry which has been accepted
and adhered to by the major manufacturers for many years (30+).
Response: RE: WaterSense testing of distance of throw to align with value reported by the
manufacturer.
Yes.
Rationale: It is reasonable for WaterSense to require this. There are details that must be addressed
like acceptable variation, minimum/maximum/average radius of throw, and adjustment of radius of
variable arc nozzles during the test because the mechanics of changing arc impacts radius performance
(which is commonly understood by the user). There are also practical limits present when small plastic
injection-molded nozzles are used. Variation in the manufacturing process is unavoidable and presents
real barriers to performance improvement beyond a certain point.
Response: RE: Appropriate percent exceedance/overspray.
ASAE S398.1 is used to measure radius. ASAE S398.1 does not define "exceedance" of radius. Until this
is defined and tests performed against that criterion, Rain Bird does not support this as a criterion for
the WaterSense draft specification.
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Rationale: Rain Bird does not believe this requirement is useful.
a. Rain Bird knows of no useful technology to control or reduce the degree of "exceedance" of
radius.
b. The amount of water that falls beyond the ASABE S398.1 radius is not material. The minimum
amount of water captured in a catch can during an ASABE S398.1 radius test 0.01 inches. One
foot is added to the distance of the farthest catch can with that minimum amount of water to
determine radius. That means that less than 0.01 inches of water falls to the ground at the
stated radius defined by ASABE S398.1.
c. Much of the "exceedance" or overspray observed in the landscape is caused by windblown
spray. Wind blowing in the same direction as the direction of spray will carry the water farther
than if there is no wind. Some amount of overspray is unavoidable.
d. Requiring a maximum amount of spray radius beyond the ASABE S398.1 defined radius requires
a non-existent level of control of how water behaves once it leaves the nozzle.
H. Distribution Uniformity Section (starting on page 12)
I. Topic: "Early studies on water savings associated with MSMT sprinkler nozzles focused on DU as the
likely mechanism for anticipated water savings. Researchers and utilities suggested that MSMT
sprinkler nozzles might use less water and result in healthier landscapes because they distribute
water more evenly. Since DU quantifies this metric, stakeholders suggested that DU might be an
appropriate way to measure water efficiency, and some researchers attempted to quantify the range
of DU that would result in water savings. Many of these studies included irrigation audits conducted
in a controlled environment, such as afield or concrete surface.27,28,29'30'3132 While many of these
studies reported higher D Us for MSMT sprinkler nozzles, the researchers did not observe the
expected water savings." (underline added) (From the Distribution Uniformity as Water Efficiency or
Performance Criteria section on pages 13 & 14)
Comment: Given this statement, WaterSense should not conclude that MSMT spray sprinkler nozzles
are high efficiency.
a. The "early" research that showed no savings with MSMT spray sprinkler nozzles has not been
refuted.
b. WaterSense says the reason that MSMT spray sprinkler nozzles are more efficient is the savings
studies cited in Appendix A. Those studies were conducted in a way that cannot isolate the
MSMT spray sprinkler nozzles as a source of the water savings.
c. The Sovocool (2014) study (one of the 'early studies" that showed no savings) that compared
water use of fan spray sprinkler nozzles to MSMT spray sprinkler nozzles was a study which
tightly controlled conditions and did a superior job of isolating water use to the nozzle type. It
showed no savings after a short initial period of some savings. This study is very relevant when
considering if MSMT spray sprinkler nozzles are directly responsible for lower irrigation water
use.
d. Appendix A savings studies show that if homeowners are motivated to pay attention to their
irrigation system, they take actions that result in lower water use compared to those who take
no action and continue the same practices as in the past. They also show that rebating spray
sprinkler nozzles that are promoted as 'high efficiency' spray sprinkler nozzles adequately
motivates some homeowners to make changes that result in about 10% (according to
WaterSense) water savings. They do not isolate which user actions caused the water savings or
to what degree each element of change caused the water use reduction.
2. Topic: "WaterSense invites manufacturers to submit laboratory data on DUfor HES and standard
spray sprinkler nozzles. WaterSense also invites manufacturers to indicate whether they collect DU
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data in accordance with ASABE/ICC 802-2020 or through another method." (From the Distribution
Uniformity as Water Efficiency or Performance Criteria section on page 14)
Response: RE: Submission of laboratory data.
Rain Bird is open to discussing this possibility.
Rationale: Rain Bird would entertain a specific request for information.
Response: RE: Collection method of DU data.
Rain Bird performs catch can testing of nozzles using ASAE/ASABE S398.1 which is required by
ASABE/ICC 802-2020. The result of this testing is used to determine sprinkler radius and is used to
generate a distribution rate curve. Rain Bird uses those data to determine Distribution Uniformity.
Rationale: No further comment.
3. Topic: "WaterSense would like stakeholder input on whether DU should be used in a specification
to establish a minimum level of performance or used to differentiate HES and standard spray
sprinkler nozzles." (From the Distribution Uniformity as Water Efficiency or Performance Criteria
section on page 15)
Response: Distribution Uniformity should be used in the WaterSense label specification for spray
sprinkler nozzles. It should be set as a threshold level of 65% or higher.
Rationale: California's Model Water Efficiency Ordinance (MWELO) requires DU of 65%. Dukes (2006)
research suggests that once 50% DU is reached, improvement in DU beyond this level provides
diminishing returns. Dr. Dukes has stated in conversation with Rain Bird that this study has some noise
in the data, so Rain Bird supports using 65% DU to define HES nozzles to conform with MWELO. Rain
Bird does not support a requirement higher than 65%.
4. Topic: "WaterSense invites stakeholders to submit data pertaining to the relationship between DU
and water savings and/or performance (e.g., landscape health)." (From the Distribution
Uniformity as Water Efficiency or Performance Criteria section on page 15)
Response: Rain Bird has nothing to contribute on this subject.
Rationale: No further comments.
I. Water Droplet Size and Spray Pattern Section (starting on page 15)
1. Topic: "As noted in Table 2, standard sprinkler nozzles produce fine droplets (resembling mist) that
can be blown by the wind and diverted from their intended destination. MSMT sprinkler nozzles have
a spray pattern that creates larger droplets and reduces misting.33 The spray pattern allows MSMT
sprinkler nozzles to distribute water more evenly across the landscape despite their lower flow rate.
The larger droplet size could also prevent water from being applied to undesirable areas, such as
hardscapes, potentially decreasing the total water applied for irrigation." (Page 15)
Comment: Given the substantial consequences of water droplet size in this context, Rain Bird would like
to see the data which supports the claim that MSMT spray sprinkler nozzles have larger droplets and
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reduce mist. Table 2 also claims that MSMT spray sprinkler nozzles also have larger water droplets at
"high" pressure.
2. Topic: "In contrast, MSMT sprinkler nozzles produce larger droplets that may be more resistant to
wind, meaning that more of the water emitted is likely to travel to and be used by the plants for
which it was intended, reducing the likelihood of brown spots." (From Droplet size or spray pattern
as Water Efficiency or Performance Criteria - Bottom of page 15)
Comment: Given the substantial consequences of water droplet size in this context, Rain Bird would like
to see the data which supports the claim that MSMT spray sprinkler nozzles have larger droplets and
have more wind resistance than other nozzles.
3. Topic: "WaterSense invites stakeholders to share data on droplet size and water efficiency,
especially collected in accordance with ISO Standard 15886-2:2021. WaterSense welcomes
feedback on whether stakeholders think droplet size should be included as a criterion in a
WaterSense specification." (From Droplet size or spray pattern as Water Efficiency or Performance
Criteria - top of page 16)
Response: Rain Bird believes that water droplet size distribution should be included as an element of
the definition and testing protocol of spray sprinkler nozzle efficiency.
Rationale: An ANSI standard should be developed that defines spray sprinkler nozzle efficiency and
specifies a testing protocol for measuring water droplet size. Research should be conducted to develop
a water droplet size distribution coefficient to wind drift and evaporation losses in the field. Spray
sprinkler nozzles could then be tested indoors to determine their water droplet size distribution
performance and the losses due to wind drift and evaporation could be estimated using the coefficient.
WaterSense (and others) could use results of this testing to set label performance specifications.
J. Possible Additional Criteria From Existing Standards Section (starting on page is)
1. Topic: "WaterSense welcomes stakeholder feedback on whether to require these sections of
ASABE/ICC 802-2020 in a potential specification." (From Possible Additional Criteria From Existing
Standards section on page 19)
Response: Rain Bird supports requirements of these sections of ASABE/ICC 802-2020.
Rationale: No further comment.
K. Existing Performance Data Section (starting on page 19)
1. Topic: "WaterSense invites stakeholders to share any additional performance data on HES
sprinkler nozzles." (From the Existing Performance Data section on page 20)
Response: Rain Bird has no data to share.
Rationale: No further comment.
L. Product Marking, Documentation, and Marketing Section (starting on page 20)
1. Topic: "WaterSense invites stakeholder feedback on these proposed product marking and
documentation requirements." (From the Product Marking, Documentation, and Marketing section
on page 21)
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Response: Rain Bird supports these requirements and recommends that WaterSense require spray
sprinkler nozzles be installed on WaterSense labeled spray sprinkler bodies with the appropriate
pressure regulator setting and with markings on the packaging indicating that the combination of
products is required to satisfy the label requirements.
Rationale: No further comment.
M. Estimated Water Savings Section (starting on page 21)
1. Topic: "WaterSense is interested in feedback from stakeholders on whether the estimated
percentage of outdoor water used for spray irrigation is accurate, or whether spray irrigation
typically accounts for more than 50 percent of outdoor water use in residential properties." (From
the Estimated Water Savings section on page 22.)
Response: Rain Bird has no definitive data on this subject.
Rationale: The context of this question is not clear. Is WaterSense asking if spray irrigation from
products that would be included in this draft specification represent 50% of all outdoor water use, all
residential outdoor water use, all residential water use of irrigated homes, all residential water use of
homes irrigated with underground irrigation systems or something else?
Regardless, it is Rain Bird's opinion based on the sales of spray sprinklers compared to all other forms of
irrigation that the WaterSense estimate that 50% of outdoor water use is attributable to spray irrigation
is very high when each device type's area of coverage is applied and totaled. This remains the case even
when the context of the question is water use of residential underground irrigation systems, not all
residential outdoor water use.
In addition, it should also be considered that fewer than 50% of homes in the US have underground
irrigation systems. Many homes are irrigated with sprinklers attached to garden hoses which are
dragged from place to place. Sprinklers on garden hoses are more likely to be something other than
sprays. Many homes have no irrigation and are not irrigated by any means.
2. Topic: "WaterSense is interested in stakeholder feedback on spray sprinkler nozzle replacement
behaviors. For example, do stakeholders typically replace nozzles after a designated period of
time, or do they wait until they need to fix malfunctioning spray sprinkler nozzles in the event of a
problem? Specifically, are there data indicating how long spray sprinkler nozzles are installed in
the field before being replaced, and/or how long spray sprinkler nozzles typically last in residential
settings?" (From the Estimated Water Savings section on page 22.)
Response: Rain Bird has only anecdotal evidence of how long Rain Bird products last in service or when
users choose to replace nozzles. Rain Bird residential products are designed and tested to last about 7
years in the most extreme conditions expected.
Rationale: Product warranties are not a good indicator of product life. Warranties are marketing
programs. For example, some products offer lifetime warranties. Those products are not expected to
last 75+ years. Long duration warranties are many times meant to increase consumer confidence in the
product's reliability. Rain Bird warranties are not equal to Rain Bird's opinion of expected life.
3. Topic: "WaterSense is interested in feedback from water utilities on promoting WaterSense
labeled HES sprinkler nozzles. In particular, WaterSense is curious whether water utilities have
concerns about whether consumers with HES sprinkler nozzles could meet their irrigation needs
with watering windows in place." (From the Communicating Savings Section on page 23.)
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Response: Lower application/precipitation rates increase the exposure time of water suspended in the
air and subject to wind drift and evaporation losses. The ideal irrigation conditions water window is
much smaller than most water windows imposed by water utilities.
Rationale: An irrigation zone with a lower application rate will take more time to apply the necessary
amount of irrigation water compared to an irrigation zone with a higher application rate.
a. The time water is exposed to wind drift and evaporation is increased by a zone with a lower
application rate. In other words, the same volume of water is suspended in the air twice as long
in an irrigation zone with an application rate that is half that of another irrigation zone. Until
more is known about the losses associated with wind drift and evaporation, the significance of
this effect cannot be known. Rain Bird believes it is very significant.
b. Many areas of the country experience the least amount of wind in the early morning hours.
Ideally, all irrigation would occur during this short time. Some low precipitation rate systems
would more likely be operated for some portion of its total run time during less ideal wind
conditions resulting in more losses.
G. Communicating Savings Section (starting on page 22)
1. Topic: "WaterSense is interested in stakeholder feedback on suspected reasoning behind potential
water savings, including any information on whether stakeholders change irrigation schedules
after a retrofit. WaterSense invites stakeholder opinions on irrigation runtimes, including
preferences for duration of irrigation." (From Communicating Savings section on page 23)
Response: The most likely source of potential water savings is appropriate management/operation of
the irrigation system.
Rationale: A professional golfer was once quoted as having said that if you give him only a croquet
mallet, he will beat any amateur using the best set of golf clubs ever made.
A similar statement could be made for irrigation. A knowledgeable irrigation manager will use less
water and have better landscape performance on a mediocre irrigation system than the average user
making irrigation scheduling decisions on a perfectly designed, installed, and maintained system. This is
why the WaterSense decision to label weather-based irrigation controllers early in the program life was
wise. Weather-based irrigation controllers reduce the need for a knowledgeable end-user through
automation.
Response: RE: Preferences for duration of irrigation.
Rain Bird has only anecdotal information on user preferences of duration of irrigation.
Rationale: In Rain Bird's anecdotal experience, irrigation controller settings are highly variable.
Response: Rain Bird looks to the WaterSense program for product efficiency design criteria.
Rationale: It may be attractive to some to impose product restrictions (application rate) which cause the
user to unknowingly use the product in a way that uses less water or cause conditions that many users
or the community would find undesirable. However, this prescriptive approach (limiting application
rate) does not promote efficient irrigation design or management practices. Manufacturers may be
compelled by this proposed WaterSense prescriptive approach to ignore other elements of waste (wind
drift and evaporation, deep percolation) to meet the WaterSense label specification. This prescriptive
approach may stifle water efficiency innovation by de-emphasizing investment in the development of
important criteria that would result in more efficient irrigation. Innovation and solutions that result in
less water use would tend to have lower priority in product design investment decisions.
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WaterSense should set a spray sprinkler nozzle efficiency performance threshold for the labeling of
spray sprinkler nozzles rather than prescribe a product feature or application rate which is not an
element of spray sprinkler nozzle efficiency.
The definition of spray sprinkler nozzle efficiency is not currently agreed upon in the landscape irrigation
industry or among other stakeholders nor is there an agreed upon testing protocol for spray sprinkler
nozzle efficiency. These should be in place before WaterSense finalizes this label specification.
Response: Other irrigation efficiency information should not be ignored.
Rationale: Information regarding the water droplet size performance of spray sprinkler nozzles has not
been developed.
a. The correlation between water droplet size distribution of a nozzle and the resulting water loss
due to wind drift and evaporation has not been developed.
b. If the application/precipitation rate of sprinklers were to be reduced to not exceed the
infiltration rate of soils, runoff as a waste signal to the user, community and policing authorities
would be eliminated. The irrigation systems scheduled to apply too much water would still
result in waste. The waste would simply be undetectable due to deep percolation. Perhaps this
deep percolation waste would be less than is the current amount of runoff waste. This is not
known. However, deep percolation waste is much more difficult for the user, community, and
policing authority to detect.
It is also possible that waste would increase because those users who now respond to the runoff
waste signal and adjust their irrigation schedule would no longer have a trigger.
2. Topic: "Unfortunately, none of the savings studies discussed in Appendix A examined irrigation
schedules before and after retrofits, so WaterSense cannot determine if water savings are due to
lower flow rate alone, or if factors such as irrigation scheduling or other system adjustments
impacted the results." (From the end of paragraph 3 on page 23)
Rationale: Rain Bird agrees that it is unfortunate that these studies did not tightly control several factors
like irrigation schedules.
a. If the savings ARE due to the other factors cited in the quote, those savings may not be
persistent. If the landscape begins to suffer due to the water losses cited above, users are likely
to increase irrigation schedules. Users will tend to only change irrigation when the landscape
suffers. This would result in users adding time to the irrigation schedule and tending not to
reduce it when irrigation demand drops.
b. If the savings shown in Appendix A research are a result of the other factors, MSMT spray
sprinkler nozzles should not be singled out as efficient while other efficient nozzles are excluded.
c. Perhaps if those other 'high efficiency' nozzles were the subject of rebates, they also would
cause the same behaviors that resulted in lower water use.
d. Perhaps these "other factors" explain the results of the Sovocool (2014) study in which fan spray
sprinkler nozzles were retrofitted with MSMT spray sprinkler nozzles under highly controlled
conditions. The initial results showed the savings that were expected. However, a short time
later, water use in the irrigation system increased back to the pre-study levels.
i. Rain Bird had a conversation with Kent Sovocool shortly after this follow-up study was
final.
ii. It was confirmed that Mr. Sovocool had high faith that no errors were made in
conditions and controls of the study. He was bewildered that initial savings were not
persistent and water use reverted to pre-study levels.
iii. It was suggested that other losses like wind drift and evaporation (which were not
considered in the irrigation schedule development) resulted in inadequate landscape
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irrigation. Perhaps users noticed the landscape suffering. Perhaps they increased the
irrigation schedules until the landscape performance improved,
iv. Mr. Sovocool acknowledged that this could explain the results. We did NOT conclude
that this IS what happened. We agreed that we DO NOT KNOW,
e. The source of savings reported in Appendix A research is not known and WaterSense should not
base its WaterSense label specification on this research until more is known if the source of the
savings is the MSMT spray sprinkler nozzle. WaterSense should not require low precipitation
rate of nozzles to qualify for a WaterSense label before more is known about spray sprinkler
nozzle efficiency and the drivers of water savings in some field applications. There is significant
risk that WaterSense may be harming the overall efficiency of the product category if it
continues its current path.
3. Topic: "WaterSense is interested in feedback from water utilities on promoting WaterSense
labeled HES sprinkler nozzles. In particular, WaterSense is curious whether water utilities have
concerns about whether consumers with HES sprinkler nozzles could meet their irrigation needs
with watering windows in place." (From the Communicating Savings Section on page 23.)
Response: Lower application/precipitation rates increase the exposure time of water suspended in the
air and subject to wind drift and evaporation losses.
Rationale: An irrigation zone with a lower application rate will take more time to apply the necessary
amount of irrigation water compared to an irrigation zone with a higher application rate.
a. The time water is exposed to wind drift and evaporation is increased by a zone with a lower
application rate. In other words, the same volume of water is suspended in the air twice as long
in an irrigation zone with an application rate that is half that of another irrigation zone. Until
more is known about the losses associated with wind drift and evaporation, the significance of
this effect cannot be known. Rain Bird believes it is very significant.
b. Many areas of the country experience the least amount of wind in the early morning hours.
Ideally, all irrigation would occur during this short time. Some low precipitation rate systems
would more likely be operated for some portion of its total run time during less ideal wind
conditions resulting in more losses.
Rain Bird appreciates the opportunity to comment on the WaterSense Notice of Intent and looks
forward to working collaboratively with US Environmental Protection Agency WaterSense Program and
all other like-minded stakeholders in the development of the WaterSense Draft Specification for Spray
Sprinkler Nozzles.
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Andrew Morris
Affiliation: Alliance for Water Efficiency
Comment Date: March 22, 2023
Email Text:
Dear WaterSense Staff,
Please find AWE's comments attached.
Thank you,
Andrew D. Morris| Senior Manager of Policy and Programs
Alliance for Water Efficiency
e: andrew@a4we.org
p: 770-906-1888
w: www.allianceforwaterefficiency.org
Join us for the AWE Symposium in Chicago g 1-3, 2023.
Email Attachment:
See pages 49 through 50.
EPA
4
WaterSense
48
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AWE Public Comment for Spray Sprinkler Nozzle NOI
Commenter Name: Ron Burke, President and CEO
Commenter Affiliation: Alliance for Water Efficiency (AWE)
Date of Comment Submission: March 22, 2023
Topic: General
Comment: AWE is supportive of WaterSense labeling for high-efficiency spray sprinkler
nozzles.
Rationale: Given its recognition in the marketplace, a WaterSense label could indeed be an
important distinguishing factor in creating utility incentive programs, designing landscape
irrigation systems, and informing purchasing decisions.
Topic: Intended Scope of the Specification
Comment: AWE members had questions about whether the differences between standard
spray sprinkler nozzles and multi-stream, multi-trajectory (MSMT) nozzles should be
grouped together under a single specification or separated into two specifications.
Rationale: Separate definitions (or separate specifications) are needed because spray
nozzles and MSMTs differ in terms of components, materials, price point, etc.
Topic: Whether water utilities have concerns about whether consumers with HES sprinkler
nozzles could meet their irrigation needs with watering windows in place.
Comment: AWE's utility members do not generally anticipate issues with their customers
being able to meet their irrigation needs during watering windows, whether in general or
during drought. Utilities that understand the benefit of low-precipitation spray nozzles can
adjust water window policies, if necessary. A malleable policy issue like watering windows
shouldn't be a barrier to efficient irrigation technology nationally.
Rationale: In January 2020 AWE released a research report titled Use and Effectiveness of
Municipal Irrigation Restrictions During Drought, and all the watering windows reviewed
as part of this project focused on limiting landscape irrigation to certain specified day or
days of the week. This reflects the general practice among utilities and states, which
focus on day and time restrictions that still provide an adequate number of hours on
designated watering day(s) for landscape irrigation. Common examples include limits
like - before 9 a.m. or after 4 p.m., before 10 a.m. or after 7 p.m., etc. There are a few
rare exceptions where utilities have limited run times to much narrower windows or
even limited the run times for each zone of an irrigation system. These much narrower
limits are not a best practice, and even some utilities imposing them seemed to
recognize this by granting exceptions for landscape irrigation systems that could not
function as designed under narrow limits.
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Topic: Irrigation Runtimes and Duration of Irrigation
Comment: The specification should make it clear that run times should be evaluated when
replacing traditional nozzles with HE or MSMT nozzles.
Rationale: Depending on the specifics of the landscape irrigation system and the
landscapes being irrigated, evaluation is necessary to determine whether water savings can
be achieved by replacing traditional nozzles with HE or MSMT nozzles or whether it will
merely increase runtimes. Water savings can be more predictably achieved when designing
new landscape irrigation systems with HE or MSMT nozzles from the start.
50
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Ryan Moore
Affiliation: New York State Energy Research and Development Authority (NYSERDA)
Comment Date: March 23, 2023
Email Text:
EPA
4
WaterSense
To whom it may concern,
Please find attached NYSERDA comments on Watersense's Notice of Intent (NOI) to
develop a Draft Specification for Spray Sprinkler Nozzles. Thank you for the opportunity
to weigh-in on this NOI. Any questions or concerns, please email or call me at the
number below.
Thanks again,
Ryan
Ryan Moore
Project Manager
Codes, Products, and Standards
NYSERDA
17 Columbia Circle | Albany, NY 12203-6399
P: 518-862-1090 x3267 | F: 518-862-1091 | E: rvan.moore@nvserda.nv.gov
nvserda.nv.gov
follow : friend : connect with NYSERDA
VIEW
J VISION, MISSION, AND PROMISE
THAT
OUR ORG;
mc
CT GUIDE
NT AND FUTURE INITIATIVES.
(READ THEM ONLINE 0j) (wATCH THEM IN ACTION^
Email Attachment:
See page 52.
51
April 26, 2023
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Commenter Name: Chris Corcoran
Commenter Affiliation: New York State Energy Research and Development Authority
(NYSERDA)
Date of Comment Submission: March 23, 2023
Topic: General Support
Comment: NYSERDA appreciates the opportunity to submit comments to WaterSense
on the Spray Sprinkler Nozzle Notice of Intent to develop a Draft Specification.
NYSERDA's mission is to advance clean energy innovation and investments to
combat climate change, improving the health, resiliency, and prosperity of New
Yorkers and delivering benefits equitably to all. NYSERDA is strongly supportive of
WaterSense developing a new specification for this product category. New York has
recently established appliance standards that include Spray Sprinkler Bodies
referencing the WaterSense specification; NYSERDA looks to the WaterSense
program to help establish meaningful opportunities for water savings. A specification
for Spray Sprinkler Nozzles is expected to lead to water and associated bill savings
for New Yorkers. Please do not hesitate to reach out with any questions. Thank you.
Rationale: N/A
Suggested Change (or Language): N/A
52
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Commenter: Tres Wangsgaard
Affiliation: Orbit Irrigation, LLC / Hydro-Rain
Comment Date: March 23, 2023
Email Text:
Hi WaterSense,
Please find attached our comments on the NOI to Develop a draft standard for Spray
Sprinkler Nozzles.
Thanks,
Tres Wangsgaard (CLIA, CIC, CWCM-L)
Global Director of Product Development Engineering
Orbit Irrigation Products / Hydro-Rain
Elven Webb (CLIA, CIC, CIT)
Product Line Manager - Heads
Orbit Irrigation Products / Hydro-Rain
Email Attachment:
See pages 54 through 58.
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April 26, 2023
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Commenter Names: Elven Webb(CLIA, CIC, CIT), Tres Wangsgaard (CLIA, CIC, CWCM-L)
Commenter Affiliation: Orbit Irrigation, LLC / Hydro-Rain
Date of Comment Submission: 3/23/2023
Topic: NOI for Spray Sprinkler Nozzles
Comment: We applaud the 2017 specification for Landscape Irrigation Sprinklers, ensuring that
spray sprinklers are operating at their optimum pressure range results in real water savings.
Over-pressurized sprinkler systems with the new compliant pressure regulating heads will no
longer waste water as it blows away as mist in the wind. That said, we have several concerns
about the new proposed standard for nozzle efficiency. If nozzles are not used at the optimum
pressure range, OR not used in a sprinkler system with proper spacing for a particular nozzle, we
are going to be advertising an efficiency that will not be realized in application. This would be
particularly true in nozzle retro-fit situations where moving individual heads to be optimally
spaced will likely neither be apparent to or understood by the end user. How will that be
communicated effectively so as not to mislead the end user? (That pressure range and system
design are as important or more important than "nozzle efficiency"?).
Rationale: DU is a measure of system efficiency, not nozzle efficiency. As we read this
proposed draft specification, we fully understand the intent and agree that in an ideal world
where everyone is a certified irrigation contractor, it could work. But as written, it will be likely
be misused to oversimplify efficiency, and the end goal of water savings will not be realized. Car
mileage efficiency makes sense as a comparative expectation of gas mileage between vehicle
models. If you are driving uphill or against a headwind, you are not going to achieve the
mileage efficiency advertised, but every vehicle should have a proportional decrease in
efficiency to those outside factors, but note that a car is a complete system. The draft standard
is proposing to assign blanket efficiency ratings to a single component of a system. When the
water savings will require that the whole system be run at optimal conditions.
The auto industry does not advertise a miles per gallon ratings for car tires. The petroleum
industry does not advertise a miles per gallon rating for gasoline.
Irrigation system efficiency (DU) depends at least as much upon the optimum system design and
operating conditons as it does any idealized individual component efficiency. We feel that
putting an efficiency number (DU) rating on a component is going to mislead the end user that
they are saving water. This standard would also result in water districts into offering incentives
and legislative bodies creating legislation for water savings that a nozzle alone cannot deliver.
Suggested Change: WaterSense approved nozzles should require at a minimum labeling the
head prominently with the radius of spray range (for head to head spacing) and optimum
recommended pressure range for which the nozzle meets the distribution uniformity
requirements for WaterSense efficiency "compliance"... something like that. Given that this
draft standard is targeting a 10% reduction in water usage across sprays, and sprays are
assumed to be 50% of sprinkler system distribution, isn't this a lot of effort to save, at 100%
implementation, a 5% savings in residential irrigation water. We think that the expansion of
smart timer conversion incentives and pressure regulated spray body incentives would result in
much greater net water savings than a nozzle efficiency standard.
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Topic: MSMT nozzle patents
Comment: Multiple utility patents appear to limit manufacturers from making MSMT nozzles.
Developing a specification for spray sprinkler nozzles would likely result in legislation that would
benefit a few companies and effectively lock others out of the spray nozzle market.
Rationale: There are a number of patents on MSMT and other HES nozzles.
Suggested Change: Do not offer WaterSense certification to strip nozzles (square or rectangular
pattern MSMT nozzles that have essentially locked everyone but Hunter out of the strip nozzle
market). So as not to create a monopoly in states that turn this standard into legislation.
Topic: Precipitation Rates and water conservation efforts
Comment: MSMT and HES spray nozzles don't work well with non-potable water. This will
require manufacturers to effectively communicate their recommendations for where it is best
to use MSMT and HES nozzles and installation instructions.
Rationale: MSMT and HES nozzles require filtering on a finer scale. With non-potable water,
more filtration than the nozzle alone can supply. Or frequent filter cleaning.
Suggested Change: manufacturers should be required to communicate best practices in their
instructions and product information so that the communicated savings are accurate.
Topic: Matched Precipitation Rates (MPR)
Comment: Communicating savings will be problematic from one family of nozzles to another.
Rationale: The MPR of nozzles exists within families of nozzles (Families: adjustable, fixed,
MSMT, and HES) but not across manufacturers' whole product lines. When defining MPR, is it
possible to say to the consumer that the adjustable nozzles all have a similar precipitation rate,
fixed spray nozzles all have a separate precipitation rate, and MSMT/HES nozzles have a
different precipitation rate, without mixing families and still get an efficiently watered lawn with
good plant health?
Suggested Change: Manufacturers must clearly state which nozzles they recommend grouping
together for MPR.
Topic: Matched precipitation rate.
Comment: MPR is not possible across the whole adjustable nozzle family.
Rationale: Every manufacturer has outliers in their nozzle families that cannot get matched
precipitation rate. The consumer may feel that they need to get a four-foot, or eighteen-foot
adjustable nozzle to fit their landscape's needs. The apertures in those nozzles are impossible to
match with other distances in the family.
Suggested Change: manufacturers cannot claim MPR across the adjustable (not MSMT) family.
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Topic: Distance of Throw and Precipitation rates.
Comment: We agree that the distance of the throw needs to meet a standard that the whole
industry can agree on. ASAE S398.1 sets a reasonable standard. Interpolation of that data may
produce some interesting results.
Rationale: All manufacturers have published performance charts of their nozzles. The
interpolation of current data has resulted in performance charts that look more mathematically
precise than the real-world results, i.e., the quarter pattern nozzle has one-fourth of the GPM
and PR of the 360-degree nozzle at the same distance and pressure. That belies the actual data.
The pattern that water sprays out of fixed nozzles does not allow for such mathematically
precise results. Will manufacturers agree to publish the real numbers? Will "Interpolation of
data" allow them to continue the current trend? Does that enable proper communication of
savings if the performance data is not precise?
Suggested Change: Proper interpolation of data must be defined. Also precipitation rates
probably shouldn't be a requirement of HES nozzles when breaking the watering cycle into cycle
and soak intervals, done automatically on smart timers when the correct data is supplied to the
timer, can be used as an alternative method to ultra-low precipitation rates.
Topic: Existing Performance Data
Comment: We have a concern about the Existing Performance data and Dr. Duke's research.
Rationale: The math used to get to the results of the graph on page nineteen in the NOI needs
to be reexamined. Dr. Duke shows a chart suggesting that HES nozzles have a more consistent
flow rate across a pressure range than non-HES nozzles. However, to illustrate his point he
increases the pressure range and therefore the variability of the non-HES nozzles (testing from
30psi to 85psi) across a 55psi range, while the HES nozzles are tested across a 40psi pressure
range (45psi to 85psi). While I think that we can all agree that slower precipitation rates on
slopes or high clay content soils can reduce runoff in higher clay content soil types, here are
other methods to accomplish the same effect with smart timers that will automatically break
zone run times into several cycle and soak watering periods, without requiring ultra low
precipitation rates.
Suggested Change: The math used in this justification of "consistency" is flawed on several
fronts. You can't draw conclusions on "flow rate consistency" from a study where HES nozzle
test pressures were increased by 89% and the non-HES test samples were tested at pressures
which varied 183% (pressure variation on the non HES group was over double the increase of
the HES sample group). I've heard the excuse that suggested operating pressure of 30psi for
standard spray nozzles and 45 psi for MSMT nozzles was the rationale, but show me where
anyone has suggested that 85psi is suggested operating pressure for non-HES nozzles. Also it
was suggested that this flow rate consistency data demonstrated a pseudo-pressure regulation
that isn't there, and it's clearly not. It's mathematical smoke and mirrors.
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Topic: Existing Performance Data : Water Savings Potential Even Higher for Retrofits
Comment: Not likely. Head to head watering is generally how spray nozzles are designed to
water most efficiently. There is absolutely zero data or even plausible rationale offered in this
draft for suggesting that substituting MSMT nozzles (with an effective watering radius of 1.5x or
2x that of a standard nozzle) into an existing sprinkler system will result in more water savings.
Rationale: MSMT nozzles are designed to be most efficient when operated at head to head
coverage for the rated radius of throw and suggested pressure range. Placing MSMT nozzles
into an existing system designed with nozzles with a shorter radius of throw is not optimal nor is
there any reason to think that it would result in larger water savings. If head to head spacing is
optimal by design, less than head to head spacing is going to result in a lower DU and most likely
overspray onto surfaces that you do not want watered.
Suggested Change: As recommended earlier it needs to be made very clear that the efficiencies
advertised will not be realized unless system layout is taken into account. We pointed out
earlier in this response that there is a huge potential for people to misinterpret a component
efficiency rating to be a system efficiency rating and this draft standard is implying if not directly
stating this fallacy in the last paragraph of Section V. Existing Performance Data. These nozzles
are manufactured to have a lower DU, but that uniformity requires the nozzles to be placed in a
sprinkler system with the spacing for which they were designed.
Topic: Product Marking, Documentation, and Marketing
Comment: We don't agree with a published DU or DULQ. Any testing or manufacturing is
subject to error, variation, manipulation, embellishment, etc...
Rationale: The nozzle data published currently by two of the largest manufacturer's is highly
massaged, admittedly so in one case, and verified by testing in both cases. So why will this be
any different.
Suggested Change: Establish a minimum to meet the efficiency standard and eliminate the
marketing eventuality to embellish the advertised DU numbers. We agree with the
recommendation that WaterSense recommends using the sprinkler spray nozzles on a
watersense compliant pressure regulated spray body. It makes sense to ensure the nozzle is
operating at its prescribed pressure range.
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Topic: Estimated Water Savings
Comment: Targeting 10% water savings with the assumption that sprays constitute 50% of
residential watering... so (upon 100% conversion to HES nozzles) we're only saving 5% of
residential watering? Again it seems like effort and money would be better spent incentivizing
PR bodies and Smart Timers over this proposed standard. Also we again take issue with the
statement that greater savings would be realized from installing HES nozzles in retrofit systems,
based on what data? Assumptions? etc.??
Rationale: Smart timers have the capability to adjust watering schedules to more closely match
local evapotranspiration conditions and only apply the water needed by the landscape.
Pressure regulated heads can ensure nozzles are watering with less misting and more water
makes it to the intended surface. WaterSense and the EPA should spend their time and money
on efforts that will best preserve our water resources, and this standard would seem to be a lot
of effort for very little increased water savings. The smart rain delay feature alone on smart
timers will save far more water than nozzle efficiency, not to mention cycle & soak, as well as
matching watering cycles with local evapotranspiration data.
Suggested Change: Pour more resources into smart timer conversions where the most savings
can be realized with the least effort. Changing out a timer is way easier than spray bodies or
nozzles, and saves more water. Once smart timers are the norm, then it makes more sense to
start chasing the lesser methods of water savings. Also nobody is checking expiration dates on
their nozzles, they replace them when they stop working (on MSMT nozzles the grease speed
governor) stops working and the nozzle radius decreases significantly.
Topic: Communicating Savings
Comment: We think paragraph 5 of Section VIII is a pretty good summation of why this standard
should be studied further before continuing forward.
Rationale: More study is needed in order to suggest run time reduction with regard to
precipitation rate, runtime changes due to reduced runoff/ better absorption into the soil.
Study the real water savings of systems installed in ideal conditions, Study the alleged
"increased savings" in retrofit applications, study the relationships between soil intake rates and
HES applications rates to determine how critical application rate actually is. We have heard
several people say that they gave up on MSMT nozzles because they feel like they have to water
too long so they didn't feel like they saved any water.
Suggested Change: Fund additional research into the actual water savings to be realized by
HES/MSMT nozzles. This draft standard mentions several places that studies have not shown
the nozzles to save water...why move forward with a standard before you have data to show it
will make a difference? We would hate to see water districts spend their limited incentive
money on replacing nozzles when the money would be better spent on the two previous better
studied water saving products (Smart timers / Pressure Regulating Spray bodies)
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Commenter: Nathan Bowen
Affiliation: Irrigation Association
Comment Date: April 5, 2023
Email Text:
Attached please find comments submitted on behalf of the Irrigation Association in
response to the EPA WaterSense NOI for Spray Sprinkler Nozzles.
Regards,
Nathan Bowen
Advocacy Director
Irrigation Association
8280 Willow Oaks Corporate Drive, Suite 630 | Fairfax, VA 22031
C: 202-209-9091 | F: 703.536.7019
nathanbowen@irriqation.org | www.irriqation.org
Save the date for San Antonio!
Planning is underway for the 2023 Irrigation Show and Education Week Nov. 27-Dec. 1.
Email Attachment:
See pages 60 through 61.
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Irrigation
» ACCnPlftTlflM
ASSOCIATION *
8280 Willow Oaks Corporate Drive, Suite 630 | Fairfax, VA 22031
Tel: 703.536.70801 Fax: 703.536.7019
www.irrigation.org
April 5, 2023
U.S. Environmental Protection Agency
WaterSense Program
1200 Pennsylvania Avenue NW
Washington, DC 20004
Re: WaterSense Notice of Intent to Develop a Draft Specification for Spray Sprinkler Nozzles
To whom it may concern:
On behalf of the Irrigation Association, we appreciate the opportunity to provide the following
comments in response to the Environmental Protection Agency WaterSense program's Notice of
Intent (NOI) to Develop a Draft Specification for Spray Sprinkler Nozzles.
The IA represents over 1,200 member companies including irrigation equipment and system
manufacturers, dealers, distributors, designers, consultants, contractors and end users. We are
committed to transforming humanity's stewardship and use of water, enabling the long-term
sustainability of the planet's water and natural resources, and improving the quality of life through a
reliable global food supply and vital green spaces.
We support the goals and objectives of the WaterSense program, and we are committed to working
with EPA and WaterSense to ensure workable specifications for the industry, communities, utilities
and ultimately consumers. As many utilities are already rebating a variety of "high efficiency" nozzle
products, we understand the value of and need for a WaterSense specification, and we stand ready
to assist in the development of such a specification.
We also note that additional work is needed to build consensus on the scope of such a specification.
Because of this, we recommend — and are committed to initiating — the development of a
voluntary, consensus-based American National Standards Institute standard that defines spray
nozzles efficiency that could then be used as a basis for a WaterSense specification. The standard
development process would forge consensus and help resolve issues IA members have raised in their
individual comments on this NOI.
To this end, we are prepared to engage with an organization such as the American Society of
Agricultural and Biological Engineers to facilitate the development of such a standard. Further, we
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recognize this recommendation requires a commitment of time and resources on the part of the IA,
and we are prepared to bring such a process to a successful conclusion.
Finally, we note that it will be critical, either through the standard-setting process or subsequent
specification development, to address how a specification for spray sprinkler nozzles interfaces with
other WaterSense specifications (i.e., irrigation controllers and spray sprinkler bodies).
We appreciate the opportunity to provide this input and look forward to continuing to engage with
WaterSense throughout this process. Please contact IA Advocacy Director Nathan Bowen
(nathanbowen@irrigation.org) with any questions.
Sincerely,
Natasha L Rankin, MBA, CAE
Chief Executive Officer
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April 26, 2023
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Commenter: Eric S. Neustrup
Affiliation: City of Bozeman's Water Conservation Division
Comment Date: April 5, 2023
Email Text:
These comments on the proposed standards were prepared by Eric Neustrup on behalf
of the City of Bozeman's Water Conservation Division. If any explanation of clarification
if necessary please reach out for further comment.
Eric S Neustrup Water Conservation Specialist
City of Bozeman | 7 E Beall St. Suite 100 | Bozeman MT
P:4065777400
Nothing in the world is more flexible and yielding than water. Yet when it attacks the firm
and the strong none can withstand it, because they have no way to change it. So the
flexible overcome the adamant, the yielding overcome the forceful. Lao Tzu
Email Attachment:
See pages 63 through 67.
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• WaterSense would like stakeholder input on its product category definition of "spray. "
sprinkler nozzle.
The two-part definition making the nozzle a distinct component from the body is very useful
since the two components accomplish different tasks in most cases. The sprinkler body is
typically responsible for the pressure regulation aspect of efficient irrigation, while the nozzle
dictates the throw and overall area to be watered.
• WaterSense would like stakeholder feedback on the intended scope of the specification.
The currently intended scope of the specification is useful in that it creates standards where there
previously were not any. I would suggest expanding the scope of WaterSense labeling to include
all products noted within the flow chart explaining the current scope (Figure 4). Having similar
standards for rotor sprinklers and valves in head sprinklers would be highly beneficial in the
future, as many of these products are useful when irrigating larger areas such as sports fields. I
would emphasize the need to create similar standards around pressure regulating valves in head
sprinklers in particular because many of these products represent so-called digital sprinklers that
have the potential to drastically reduce water use in residential irrigation systems, which
represent some of the largest shares of nonfunctional turf grass in the country.
• WaterSense is seeking stakeholder feedback on its proposal to use application rates (at
recommended operating pressure and high pressure) as a water efficiency criterion for
spray sprinkler nozzles. WaterSense is also interested in whether any manufacturers
currently use the ASABE/ICC 802-2020 test methodfor application rate it and, if so,
would be willing to share masked data with WaterSense.
The use of application rate as an indicator of a component's ability to conserve water is a very
good starting point. The NOI document lays out several reasons for this, all of which I agree
with. There is an additional reason for considering a lower application rate to be more water
conservative, though, and that is the ability to be more specific with the amount of water that is
applied. With many existing spray nozzles, it is hard to put down a smaller amount of water due
to the high precipitation rates; having spray nozzles with a lower application rate makes it easier
for homeowners and water managers to tailor the water needs of specific areas.
• Additionally, WaterSense requests stakeholder opinions on using the following
parameters to evaluate spray sprinkler nozzles:
o Test each radius in a model's product family at the full circle pattern only; and
o Test models with an adjustable radius at the maximum radius.
Testing only the full circle pattern is a good starting point. It would probably require
too much effort on the part of manufacturers to test every pattern in every radius, so limiting
testing to just the full circle is a good way of making sure there is data available on a large
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number of products. I would, however, say it is more important to test both the minimum and
maximum radius for products that have an adjustable radius. I would also recommend including
a standard that specifies a maximum deviation between the application rates for the minimum
and maximum radius.
• WaterSense seeks input on whether it should require spray sprinkler nozzles to have
matched precipitation to be eligible for the WaterSense label. What would be an
acceptable variance in application rates to ensure matched precipitation? If
WaterSense requires matched precipitation, how should EPA verify the data?
Matched precipitation is a key component of making sure an irrigation system is able to conserve
water. Making sure that the coverage over a given area is as even as possible allows for less
wasted water while ensuring that the areas with the least amount of coverage receive the proper
amount of water. By evening out the coverage, less water will be applied to the areas with the
most overlaid coverage, while making sure that areas with less overlaid coverage receive what
they need.
• WaterSense is interested in feedback from irrigation contractors about whether they
are likely to incorporate HES sprinkler nozzles in bids for new irrigation systems, any
factors that might influence their decision (i.e., new installation vs. retrofit), and
whether HES sprinklers reduce the cost of materials in practice.
Many irrigation contractors will not look at using less materials as a natural benefit, as materials
are a significant source of profit on most projects. Overall, it is a benefit to use less plastic that is
buried in the ground and unlikely to ever be removed. Retrofitting systems to include new HES
nozzles does pose issues in terms of matching the spray patterns between the HES and traditional
spray nozzles because traditional spray nozzles can have throw distances as short as 4'. In this
situation, capping heads off can help make the system more efficient, but it is not likely to make
the retrofitted system as efficient as a system that has been installed correctly from the
beginning.
• WaterSense seeks stakeholder feedback on whether ASAE/ASABE S398.1 is an
appropriate test methodfor distance of throw.
Testing the throw radius under minimum, suggested, and maximum operating pressures would
be the most useful way of accomplishing this. Most of these nozzles are likely to be installed on
sprinkler bodies that are outfitted with a pressure-regulating component, meaning it is not
necessary to make sure that the differences in performance at different pressures are minimal.
Testing at different pressures is mostly meant to help inform decisions when an existing system
is being retrofitted. In those situations, it could influence a contractor to select the nozzle that is
most likely to perform properly in a given situation.
• Do stakeholders believe it is reasonable for WaterSense to require the tested distance of
throw to align with the value reported by the manufacturer? WaterSense is also
interested in stakeholder input on the appropriate percent exceedance (e.g., percentage
greater than the rated distance of throw) to prevent water waste due to overspray.
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Manufacturer-reported specifications should be required to align with the third-party testing of
the sprinkler components in general. Making sure that the information displayed to homeowners
is correct will ensure that in the majority of situations (when homeowners work on their own
systems), head-to-head coverage is more easily attained.
• WaterSense would like stakeholder input on whether DU should be used in a
specification to establish a minimum level of performance or used to differentiate HES
and standard spray sprinkler nozzles.
DU is similar to matched precipitation in that both together create even coverage of a given area.
DU is arguably more important than matched precipitation because it represents real-world data
about how effective a given group of sprinklers is. I would suggest incorporating DU as part of
the WaterSense standard.
• WaterSense invites stakeholders to share data on droplet size and water efficiency,
especially that collected in accordance with ISO Standard 15886-2:2021. WaterSense
welcomes feedback on whether stakeholders think droplet size should be included as a
criterion in a WaterSense specification.
Of all the components of the proposed standard, this seems like the one that is least effective in
ensuring that a sprinkler system is not using excessive water. In situations with high winds, I
would suggest that it is more important to have a controller that can suspend watering during
high wind events. While increasing droplet size can help achieve efficiency in low wind
situations, my experience in the field shows that it has little effect in high wind situations.
• WaterSense welcomes stakeholder feedback on whether to require the listed sections of
ASABE/ICC 802-2020 in a potential specification.
I would suggest including the following parts of ASABE/ICC 802-2020 as part of the proposed
standard: 302.1, 302.2, 302.4, 302.5, 304.1.1, 304.1.2, 304.1.4, 304.1.5, 304.1.6, 304.2 These
standards would have the most impact in real-world landscape situations. Making sure that
sprinkler components are properly labeled, standardized, and easy to work on helps ensure that
the inevitable breaks that do occur can be dealt with in a more efficient manner.
• WaterSense invites stakeholder feedback on the proposed product marking and
documentation requirements.
The clear marking and documentation of sprinkler components in the field will have significant
impacts in terms of simplifying the repair process. Being able to easily identify the components
that need to be replaced will make getting systems back in working order much simpler than it
currently is.
• WaterSense is interested in feedback from stakeholders on whether the estimated
percentage of outdoor water usedfor spray irrigation is accurate or whether
spray irrigation typically accounts for more than 50 percent of outdoor water use in
residential properties.
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The water savings from MSMT nozzles outlined on page 21 of the NOI document (10% water
savings) is likely accurate. However, combining HES nozzles with other components like smart
controllers should allow for water savings that are greater than what each individual component
allows for. Being able to effectively make use of nozzles that apply water in a more efficient
manner will work best when managed by a controller that can take the local weather conditions
and site conditions into account.
• WaterSense is interested in stakeholder feedback on spray sprinkler nozzles
and replacement behaviors. For example, do stakeholders typically replace nozzles
after a designated period of time, or do they wait until they need to fix malfunctioning
spray sprinkler nozzles in the event of a problem? Specifically, are there data
indicating how long spray sprinkler nozzles are installed in the field before being
replaced and/or how long spray sprinkler nozzles typically last in residential settings?
I am not aware of any data examining how long spray sprinkler nozzles typically operate for or
last in real-world situations. From my experience, MSMT nozzles have a shorter lifespan than
traditional spray nozzles because they have more moving parts and smaller channels that the
water moves through. This means there are more parts to break, and it is easier for MSMT
nozzles to get clogged. Typically, nozzles are only replaced when they are broken. I have never
come across a situation where all nozzles were replaced on a regular schedule. Most systems will
include areas that are subject to more wear and tear on certain components than others.
Boulevard strips are a great example of this. Boulevard strips are subject to lots of wear and tear
from both people, vehicles, and (in colder climates) snow plowing and storage. As such,
sprinklers in those areas will break more often than ones in the middle of a lawn area. Replacing
components as they break prevents wasting components that may still have significant life left in
them.
• WaterSense is interested in stakeholder feedback on the suspected reasoning behind
potential water savings, including any information on whether stakeholders change
irrigation schedules after a retrofit. WaterSense invites stakeholder opinions on
irrigation runtimes, including preferences for irrigation duration.
Most individuals are aware that MSMT nozzles are fundamentally different from traditional
spray nozzles and adjust their run time to compensate for the new components. The water
savings from MSMT nozzles are likely a side effect of the nozzles making the homeowners more
aware of their irrigation system and water usage. When a system is retrofitted, it encourages
homeowners to think more about their irrigation system, which is often an out-of-sight, out-of-
mind component of a home. When homeowners invest their time and money in efficiency
upgrades to their system and see it in action, they are more interested in managing it in an
efficient manner.
• WaterSense is interested in feedback from water utilities on promoting WaterSense-
labeled HES sprinkler nozzles. In particular, WaterSense is curious whether water
utility companies have concerns about whether consumers with HES sprinkler nozzles
could meet their irrigation needs with watering windows in place.
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Due to the size of most residential yards, it is unlikely that switching to MSMT nozzles will
cause issues with watering their landscape within a limited time period. Most watering windows
enforced by water utilities cover the entire night and range from eight to fourteen hours,
depending on several factors. In a situation in which the presence of MSMT nozzles results in a
longer run time for a large system that exceeds the allowable watering window set in place by
the utility, the utility may allow for exemptions or relaxations to the established watering
window. This can be done by allowing the system manger/owner to water one more day per
week, while staying within the allowed watering window, or in some cases, by exceeding the
window itself. In order to ensure that the system is not over-watering the landscape, the system
manager/owner may be required to provide a watering schedule to the utility demonstrating that
the proposed watering schedule is appropriate for the landscape. From a water conservation
standpoint, many utilities would prefer to make these exceptions and accommodate those with
large systems, than encourage the installation of less efficient nozzles with higher precipitation
rates.
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Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
Commenter: Chris Davey
Affiliation: The Toro Company
Comment Date: April 7, 2023
Email Text:
Hi Joanna:
Please find attached - Toro WaterSense SSN-NOI Official Comments.
Chris Davey
Senior Product Manager, ResCom Rotors & Sprays
Toro & Irritrol Brands | The Toro Company
Host, Water Zone Radio Show
Office: (951) 785-3620 | Cell: (909) 908-2310
chris.davev@toro.com
EPA
4
WaterSense
Email Attachment:
See page 69.
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Contact Information:
Chris Davey, Product Manager
The Toro Company
chris.davey@toro.com
RIVERSIDE, CA (April 3, 2023) - Official Comments to the WaterSense® Notice of
Intent (NOI) to Develop a Draft Specification for Spray Sprinkler Nozzles.
The Toro Company is a leading manufacturer and supplier of irrigation products and
services and we are dedicated to being responsible stewards of water. We appreciate
the opportunity to comment herein and support the EPA WaterSense Program, its
objectives and goals, and are committed to work together with WaterSense and industry
colleagues in developing a Draft Specification for Spray Sprinkler Nozzles.
As it relates to the NOI's Scope - Existing spray sprinkler nozzles available today vary
widely in performance, and for good reason, so defining a measurement metric for 'high
efficiency' nozzles that delineates them from other nozzles should be determined first.
This metric could include common performance measures defined by Distribution
Uniformity (DU), Precipitation Rate and other metrics. To that end, we have considered
the very broad application of Spray Sprinkler Nozzles installed in North America and
firmly believe the Irrigation industry must first work together on the development of an
industry-led, consensus-based standard that defines spray sprinkler nozzle efficiency.
A Spray Sprinkler Nozzle specification is more complex than former standards like
Pressure Regulated Spray Bodies, Soil Moisture Sensors, Controllers and others (ICC
802) and adding a spray sprinkler nozzle specification could affect these existing specs.
The Irrigation Association (IA) has already expressed its willingness to represent the
Industry and collaborate with an organization such as American Society of Agricultural
and Biological Engineers (ASABE) or other agency to facilitate the development of such
a standard that could then be used as a basis for a WaterSense 'Efficient Spray
Sprinkler Nozzle' specification. Toro will participate in developing a standard along with
other irrigation industry constituents (manufacturers).
Toro fully realizes that an effort to develop such a standard will take time, but would like
to note there is little existing data defining 'irrigation efficiency'. Some current data exists
around AB1881 and the Model Water Efficient Landscape Ordinance (MWELO) as well
as some metrics developed by the Center for Irrigation Technology (CIT). This existing
data is useful, but is insufficient in defining many of the elements in the NOI Scope.
Toro has already provided detailed reports, data and studies to ERG on this along with
other supporting information. Toro stands ready to continue our involvement in
supporting a Draft Specification for Spray Sprinkler Nozzles and looks forward to further
engagement with our industry partners, WaterSense, ERG, the Irrigation Association
and others. Thank You!
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EPA
Comments on WaterSense® Notice of Intent to Develop a
Draft Specification for Spray Sprinkler Nozzles
WaterSense
Commenter: Kris Loomis
Affiliation: Sonoma County Water Agency
Comment Date: April 7, 2023
Email Text:
Thank you for the opportunity to provide feedback for the WaterSense Draft
Specification for Spray Sprinkler Nozzles. We appreciate your continued
commitment to the efficient use of water indoors and in the landscape. We are proud
partners and appreciate the opportunity to collaborate on this project. Please find
our comments attached.
Sincerely,
Kris Loomis || Sonoma Water
QWEL/CLIA/CID
Water Use Efficiency
Senior Programs Specialist
P: (707)52^1 1165
C: (707) 799-3621
E: Kris.Loomis@scwa.ca.gov
Mon - Thurs 7am - 5:30pm
Email Attachment:
See pages 71 through 76.
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Sonoma
Water
April 6, 2023
RE: Comments from Sonoma County Water Agency Regarding WaterSense® Notice of Intent
to Develop a Draft Specification for Spray Sprinkler Nozzles
Commenter Name: Kris Loomis CID, CLIA, QWEL
Commenter Affiliation: Sonoma County Water Agency
Date of Comment Submission: 4/6/2023
Topic: Section II Technical Background
Sprinkler definition missing shrub adapter option
Comment: NOI pages 3-5 Definitions
In the document, there is no definition to include or exclude spray nozzle shrub adapters from the
various types of sprinklers or sprinkler bodies. Shrub adapters can be used in place of a standard
sprinkler body to attach a spray sprinkler standard nozzle, high-efficiency spray (HES) sprinkler nozzle,
or multi stream-multi trajectory nozzle (MSMT). The use of shrub adapters should be a consideration
during this process. Shrub head adapters are available in various thread patterns to accommodate
different brand nozzles. There are options for integrated pressure regulation as well as models that do
not have a pressure regulation feature.
Rationale: Eliminating or excluding shrub head adapters from the specification for spray sprinklers may
have unintended consequences.
Suggested Change (or Language): Include the definition of a shrub adapter in the language of the
document so it is clear whether the use of a shrub adapter in lieu of a standard sprinkler spray body is
included or excluded from the specification when using the term "spray sprinkler body".
Topic: Section IV Water Efficiency and Performance
Page 8 refers to "Nozzles with lower application rates are considered more efficient, as they allow more
water to percolate into the soil rather than flow offsite as runoff". In the context the statement is
being used, it implies that nozzles with lower application rates in general are considered more efficient,
however the reference used (17 Baum-Haley. 2014. Op. cit.) refers specifically to MSMT and Precision
nozzles.
Comment: It should be restated that the context is specific to MSMT and Precision nozzles and not all
low flow/low precipitation rate (PR) nozzles.
Rationale: Nozzles that are low flow/low PR but produce small droplets are likely to have a much lower
efficiency than those with a larger droplet size.
Suggested Change (or Language): Rephrase the paragraph for clarity
Topic: Section IV Water Efficiency and Performance
Pages 9-10 Feedback on proposal to use application rate (at recommended operating pressure and high
pressure) as a water efficiency criterion for spray sprinkler nozzles.
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Comment: It would be interesting to see the variation in performance data between pressure regulated
and non-pressure regulated MSMTs at full radius and reduced radius. There is value to see the
application rate variance between regulated and unregulated nozzle performance but it's also important
to consider the consequence of pressure when adjustments to the radius are needed.
Rationale: It can be difficult to adjust the radius of MSMTs when the dynamic psi is higher than the
manufacturer's recommended psi. When adjusting the radius with a pressure regulated sprinkler body,
the radius is more likely to reduce than if using a sprinkler body that is unregulated and the psi is greater
than the recommended psi. If the radius of an unregulated sprinkler body is unable to be reduced as
needed, it may result in overspray and subsequent runoff due to the inability to reduce the radius as
needed.
An additional consideration is due to the likely low PR of the MSMT, run times are typically longer which
means when an MSMT has overspray, it is likely happening for an extended period of time.
Suggested Change (or Language): Consider testing MSMT nozzles regulated and unregulated at full
radius and with a reduced radius. Industry standard calls for radius reduction of no greater than 25% so
it is reasonable to test using this criteria.
You may want to ask Dr. Duke if there is any data available on the performance of MSMTs under
unregulated psi, and reduced radius nozzles.
Topic: Section IV Water Efficiency and Performance
Page 10, Input on requiring spray sprinkler nozzles to have matched precipitation to be eligible for the
WaterSense label.
Comment: Matched precipitation across nozzle series (same radius) within a hydrozone is key to having
an efficient DU.
Further, in California, new development landscapes must comply with the Model Water Efficient
Landscape Ordinance (MWELO) which states:
492.7 (M) All irrigation emission devices must meet the requirements set in the American National
Standards Institute (ANSI) standardAmerican Society of Agricultural and Biological
Engineers'/International Code Council's (ASABE/ICC) 802-2014 "Landscape Irrigation Sprinkler and
Emitter Standard, All sprinkler heads installed in the landscape must document a distribution uniformity
low quarter of 0.65 or higher using the protocol defined in ASABE/ICC 802-2014J\r\e ordinance also
specifies that:
492.7 (P) Sprinkler heads and other emission devices shall have matched precipitation rates, unless
otherwise directed by the manufacturer's recommendations.
Rationale: Without matched precipitation, areas that share the same hydrozone will have varying
precipitation rates which will result in a lower DU and longer irrigation run times. The end result is high
water use to maintain the appearance of the landscape.
By requiring matched precipitation for Spray Sprinkler Specification, it helps designers, installers and
utilities by providing clear, specific guidance towards qualified equipment.
Further, the California State Water Board is developing a new regulatory framework to phase in outdoor
residential standards for urban water utilities that will require all residential and commercial, industrial,
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and institutional (CM) outdoor water use to be limited to 80% of ETo through 2030. This will be reduced
to 63% from 2030 through 2035. Beyond 2035 standards are proposed to be 55% for residential and
45% for CM. The 2035 reductions match the current standards for new landscapes under MWELO.
While reducing outdoor landscape water use cannot be achieved by irrigation efficiency alone, having
products that perform at a higher efficiency will provide a step in the right direction. In addition to new
landscapes, existing landscapes will eventually need to be transformed to maintain compliance. Climate
appropriate plant choices combined with the use of efficient irrigation equipment and proper water
management will be essential in the process.
Suggested Change (or Language): It should be required for sprinkler nozzles within the same series to
have matched precipitation to be eligible for the WaterSense label. Acknowledging the difficulty to
achieve 100% matched precipitation across a series of nozzles, it is reasonable to allow a small variance
within the series. It should be considered to have no variance greater than 0.05 PR within a series to be
considered for the WaterSense label. Verifying this data should be done through a third party that has
experience in evaluating irrigation equipment. The Center for Irrigation Technology may already have
this information. If data is already available from prior testing, that could be used as a resource if it
meets the desired testing criteria.
Topic: Section IV Water Efficiency and Performance
Pages 10-11 Distance of throw, and figure 5, Wascher's report and hydrozone considerations
Comment: It is advantageous to have a system similar to the illustration in figure 5 that irrigates with
fewer sprinklers and fewer valves. However, something that should be considered in the design or
retrofit process is the consequence of operating various microclimates on the same valve.
Rationale: As you can see in figure 5 on page 11, the system using fewer sprinklers has sprinklers on 2
and 3 sides of the residence on the same valve. There is no indication on the diagram where northern
and southern exposures are located on the plan, however, it is clear that having more sprinklers per
zone can create an unintended consequence of a mixed microclimate hydrozone. The result is
overwatering the areas with a lower microclimate factor to meet the needs of the higher microclimate
areas on the same valve. The other system shown in figure 5 with more sprinklers and more valves is
zoned in a way that the sun exposure is likely to be consistent across the hydrozone.
Suggested Change (or Language): Perhaps the illustration used to demonstrate the ability to operate
more sprinklers with fewer valves could be zoned in a way that explains the principal of hydrozoning by
microclimate. It would also be helpful if this is mentioned somewhere to draw attention to it to those
who may not be aware of it.
Topic: Section IV Water Efficiency and Performance
Pages 11-12 comment on HES sprinklers reducing the cost of materials in practice.
Comment: The cost for HES (MSMT) nozzles are significantly higher than standard fixed spray nozzles,
however there are more factors to consider.
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Rationale: If the use of lower flow HES (MSMTs) reduces the overall number of sprinklers, valves,
controller size, and labor, it can be a way to cut down the overall cost of an installation. Smaller areas
that only require a minimal number of sprinklers will have a higher per-nozzle cost if MSMTs are used
and may actually result in a higher overall cost. If the area is larger, more sprinklers per valve can be
used, or larger radius MSMTs can be used in lieu of shorter radius fixed spray nozzles, it may be a way to
reduce cost. The overall number of sprinklers and valves will be reduced and the system will be less
expensive overall for combined materials and labor.
Suggested Change (or Language): Acknowledge that not all systems using HES (MSMT) are less
expensive. Designs should be evaluated to see if using MSMTs would be a materials and labor cost
saving approach. Overall water reduction due to improved efficiency can help save money on your water
bill and speed up the return on investment for the cost of a system using HES (MSMT).
Topic: Section IV Water Efficiency and Performance
Page 12 Do stakeholders believe it is reasonable for WaterSense to require the tested distance of throw
to align with the value reported by the manufacturer?
Comment: This information should be verifiable.
Rationale: There should be data that supports the manufacturers performance chart for sprinkler
nozzles.
Suggested Change (or Language): This data may be available and collected at the same time as verifying
the PR of the sprinkler nozzle.
Topic: Section IV Water Efficiency and Performance
Page 15, Should DU be used in a specification to establish a minimum level of performance or used to
differentiate HES and standard spray sprinkler nozzles.
Comment: Yes, using DU data should be included in meeting the criteria for WaterSense eligibility.
Rationale: Although WaterSense does not have the data to support connecting DU to water savings,
there is data to support that MSMT sprinkler nozzles typically have a higher DU than standard fixed
spray nozzles. If a system is designed and installed to produce a high DU, it would be the responsibility
and burden of the water manager to calculate an irrigation schedule that is adequate but not excessive.
This can be accomplished through educating water managers to become familiar with scheduling
techniques that calibrate run times to make up for system inefficiencies. This calculation requires
identifying the ETo, plant factor and estimated or actual DUIq to calculate the minimum and maximum
run time range for combined efficiency and landscape health. By using a runtime multiplier (RTM) or
DUIq to determine the range a reasonable schedule can be programmed and monitored.
Further, as mention in a previous comment, in California, new development landscapes must comply
with the Model Water Efficient Landscape Ordinance (MWELO) which states:
492.7 (M) All irrigation emission devices must meet the requirements set in the American National
Standards Institute (ANSI) standardAmerican Society of Agricultural and Biological
Engineers'/International Code Council's (ASABE/ICC) 802-2014 "Landscape Irrigation Sprinkler and
Emitter Standard, All sprinkler heads installed in the landscape must document a distribution uniformity
low quarter of 0.65 or higher using the protocol defined in ASABE/ICC 802-2014.
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The ordinance also specifies:
492.7 (P) Sprinkler heads and other emission devices shall have matched precipitation rates, unless
otherwise directed by the manufacturer's recommendations.
The specification of Spray Sprinkler Nozzles that have a high DU will make it easier to design, install, and
maintain systems to meet this criteria.
Suggested Change (or Language): Installers, designers, and water managers should consider taking a
course and becoming certified in water management, and or irrigation auditing to become familiar with
scheduling concepts.
Topic: Section IV Water Efficiency and Performance
Page 16, determining whether droplet size should be included as a criterion in a WaterSense
specification.
Comment: Droplet size is an important factor to consider, especially in high pressure or windy operating
conditions. The effect that droplet size has on the efficiency of the system is likely be noticeable by
calculating the PR and DU.
Rationale: Sprinkler nozzles that have a low PR and small droplet size combined are more susceptible to
wind drift and lower DU than sprinkler nozzles that have a low PR and larger droplet size.
Suggested Change (or Language): It is likely that establishing a minimum DU to meet WaterSense
specifications will rule out sprinklers with low PR and small droplet size. It may not be necessary to
establish a minimum droplet size. If droplet size does become a specification consideration, WaterSense
should also consider nozzle trajectory as an additional evaluation criteria. If a small droplet size nozzle is
combined with a high trajectory, it may be even more susceptible to wind drift and lower DU.
Topic: Section V Existing Performance Data
Page 22 Feedback from stakeholders on whether the estimated percentage of outdoor water used for
spray irrigation is accurate, or whether spray irrigation typically accounts for more than 50 percent of
outdoor water use in residential properties.
Comment: It is likely that systems that have spray sprinklers will use more water in general than systems
that primarily use drip irrigation to apply water.
Rationale: Typically systems using overhead sprinklers to apply water are irrigating higher water use
plant materials, such as turf. Turf has a high landscape plant coefficient and requires more water than
most other types of plant materials. Systems typically irrigated by drip irrigation are irrigating plant
materials or covering areas that need less water than turf. It is a safe assumption that more than 50
percent of outdoor water use in residential properties is spray if the property is irrigating turf.
Suggested Change (or Language): No change needed for the 50 percent assumption, however on page
21, it mentions the savings estimate of 2,400 gallons of water annually by replacing standard sprinkler
nozzles, and on page 22, it mentions a monetary savings of $32 annually per landscape if HES sprinkler
nozzles are installed. It would be useful to see the metrics used on calculating the savings. I am not sure
how it is saving $32 annually if the only cost is the cost of 2,400 gallons of water saved each year.
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Topic: Section VIII Communicating Savings
Page 23 opinions on irrigation runtimes, including duration of irrigation.
Comment: Lower PR sprinklers provide the unintended consequence of duration anxiety by consumers.
Rationale: For many years consumers were accustomed to irrigating at a frequency and duration that
was familiar and comfortable. Now with PRs that are close to 25% of what they are replacing, it is a
tough cognitive transition for people. The consequence can result in unintended deficit irrigation due to
the discomfort of irrigating to meet the needs of the landscape.
Suggested Change (or Language): This can be accomplished through educating water managers to
become familiar with scheduling techniques that calibrate run times to make up for system
inefficiencies. This calculation requires identifying the ETo, plant factor, estimated or actual DUIq to
calculate the minimum and maximum run time range for combined efficiency and landscape health. By
using a runtime multiplier (RTM) or DUIq to determine the range a reasonable schedule can be
programmed and monitored. This may or may not help with the duration anxiety, however, it should
improve the quality of the landscape.
Topic: Section VIII Communicating Savings
Pages 23-24 Comments related to whether consumers with HES sprinkler nozzles could meet their
irrigation needs with watering windows in place.
Comment: With unprecedented drought conditions, it has forced utilities to enforce water windows
which can be difficult to comply with if the customer has a large landscape and or a landscape that has
low PR sprinklers that require extended run time durations.
Rationale: It is possible to run out of time in a day and week to irrigate large landscapes and low PR
systems when complying with water window restrictions.
Suggested Change (or Language): It is recommended that customers limit of the size of their turf areas
and other high ETo landscape areas that use MSMT spray nozzles or other overhead low PR emission
devices. In addition, customers should look for a WaterSense labeled controller that allows for
concurrent programming to allow multiple valves to operate simultaneously to shorten the overall
watering schedule to help stay within the watering window day and hours. While this option may create
other concerns, if the hydraulic calculations and scheduling is done with some assistance or done by a
trained water manager, it is more likely to be successful.
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