Irrigation Controller Specification Update
January 10, 2008 Weather-based Irrigation Controller Specification Update
The overall goal for performance testing of weather-based irrigation controllers is to have quality test protocols that can be performed at any qualified laboratory in the country. Products that score well on the performance test should perform well nationwide. As stated in the Notification of Intent, WaterSense would like to use existing test protocols. At this time, the only protocols for this product category are the Smart Water Application Technology (SWAT) protocols drafted by industry and water utilities.
Note: As stated in the Notification of Intent (PDF) (14 pp, 193K, About PDF), WaterSense intends to include weather-based irrigation controllers and soil moisture sensors in this product category. When protocols are at an acceptable stage to be considered for adoption by WaterSense, we will move forward with draft specifications. At this time, only the protocols for weather-based irrigation controllers are at that stage. Therefore, the majority of the information below applies only to weather-based irrigation controllers. Information regarding soil moisture sensors will be available when a protocol is developed and accepted by the industry.
Based on discussions at the April meeting, WaterSense established four working groups to discuss issues pertinent to specification development. The following groups met during the summer of 2007:
Purpose: This group discussed the performance measures of irrigation adequacy and irrigation excess (defined by Draft 7 of the Climatologically Based Controllers Testing Protocol of the SWAT protocol) and the appropriate level of performance for WaterSense labeled irrigation control technologies.
Status: This group met one time and is on hold until there is agreement on a performance test protocol.
Purpose:This group discussed whether it was practical to conduct controller testing using the existing SWAT protocol in combination with a simulated weather data feed.
Status:This group met one time and concluded that simulating weather for performance testing was not feasible.
Multiple Zone Testing
Purpose: This group discussed the potential requirement for testing controllers in more than one climate (i.e., dry vs. wet).
Status: This group met twice and concluded that multiple testing facilities in differing climate zones should be available for testing, but that products should only have to be tested at one facility.
Purpose: This group discussed appropriate user interface features that should be considered by WaterSense when developing the controller portion of the draft specification.
Status: This group met four times and drafted a list of features (PDF) (3 pp, 122K, About PDF) to be considered in specification development. Note: This is a list of 10 features the working group considered to be important to water efficient irrigation control technology. WaterSense may consider this list when developing the draft specification. A public comment period will accompany the publication of the draft specification allowing the public to provide input on any features that are included. Because a public comment period will be open when the specification is in draft form, no comments on the features will be accepted at this time. These features may or may not appear in the final specification.
Working group members identified a number of outstanding issues regarding the SWAT protocol for weather-based irrigation controllers:
- Minimum test requirements (rainfall, ETo, test duration)
- Irrigation Excess due to rain and irrigation occurring on the same day
There are two facets to the resolution of these remaining issues:
- In early 2008, SWAT will be entering a revision and comment period to produce Draft 8 of the Climatologically Based Controllers Testing Protocol.
- SWAT and WaterSense are considering additional controller testing, including testing in a wet climate and using multiple laboratories.
Once the Draft 8 of the SWAT protocol is released and additional testing has been conducted, WaterSense will evaluate the development of a draft specification for this product category.