The Antigua and Barbuda Bureau of Standards (ABBS) presents this week’s article by Roger Aertgeerts, World region, Health Organization, and Pierre Studer, Chair Task Force, on Indicators and Reporting under the Protocol on Water and Health. The article entitled, “ISO Standards and Protocol on Water and Health” focuses the thought on water and more specifically the role that standardization plays in ensuring that it safe for human use and consumption. Mr. Aertgeerts and Mr. Studer say thus:
Don’t forget to filter
The importance of filtering is universally accepted and constantly emphasized by designers, equipment manufacturers and farmers.
A changeover to closed systems has led to a new requirement for fine filtering. This trend is amplified by the use of treated wastewater and a steady reduction in the size of water passages in distribution accessories (e.g. emitters and sprayers) for irrigation with a limited volume.
Agricultural filters differ from those designed for industrial and thinking water applications, since they only intend to filter part of the dirt in irrigation water. Further, to save water and energy in cleaning, agricultural filters may pass larger particles than the filter grade declared by the manufacturer, leading to equipment blockages.
The three-part ISO 9912 series of International Standards, published in 1994, addresses requirements for strainer-type filters. The development of standards for media filters and hydrocyclone filters is envisaged.
Filtering accuracy is of utmost significance. Where the filter grade is lower than the designed grade, blockage of the water dispenser may occur, causing excesses or shortages of water, and even failure of the entire system. Because of this, several developing countries have replaced closed irrigation systems with gravitational irrigation to improve the agricultural crop and save water.
Conversely, where the filter grade is higher than the designed grade, there is a pressure loss in the filtering cycle, requiring a pressure increase in the filtering system to avoid pressure drop in the water dispensers.
For these reasons, it became necessary to provide a standard that not only tests the product’s quality and durability, but also its declared filtering grade. The subcommittee has developed a method for testing filtering grades, which has been tested in the field. A first working paper on the determination of the filtering grade by this method is now in preparation.
New sprayer classification
International Standards undergo a periodic review to ensure they keep up with technological evolution, new materials and protocols, and new quality and safety requirements. This process has led to a revision of ISO 8026:1995, Agricultural irrigation equipment- Sprayers – General requirements and test methods.
The review began with a selection of the different types of sprayers available on the market, development of a new classification for them, testing in accordance with the published standard to determine uniformity of coverage, followed by another test according to a new protocol used in sprinklers. With this method, a complete sprayer classification system has been developed in accordance with various parameters, including uniformity of coverage, water-spray characteristics and flow rate regulation.
Sprinkling the world – A question of type
A drip irrigation system offers several environmental advantages, including:
increased water use efficiency, reduced water percolation, reduced evaporation;
reduced energy consumption, providing better quality and quantity of yields.
In addition to mechanical and functional requirements, ISO 9261:2004, Agricultural irrigation equipment – Emitters and emitting pipe – Specification and test methods, specifies the data to be supplied by the manufacturer for installation and operation in the field.
ISO 11545:2001, Agricultural irrigation equipment – Centre-pivot and moving lateral irrigation machines with sprayer or sprinkler nozzles – Determination of uniformity of water distribution, specifies an in-field method for measuring and determining the uniformity of water distribution in the field. It provides a procedure and guidelines to determine conformity with the performance requirements of various entities, e.g. farmers, lenders, government funding programmes supporting improved water management machinery and practices, consultants and various support agencies focusing on improving irrigation efficiency and the associated need for uniform water application.
Surface irrigation, by its very nature, does not require a great deal of equipment. Since the management of surface irrigation systems is process-related and not equipment-dependent, surface irrigation practices more often require guidelines or recommendations rather than standards.
The relevant ISO standard in this area is ISO 16149:2006,Agicultural irrigation Equipment – PVC above-ground low-pressure irrigation pipe – Specifications and test methods. Water measurement equipment has been extensively discussed and two items are currently under examination: meters for closed-pipe irrigation systems and meters for open- channel systems.
In view of the forecast for products and water requirements in the coming decades, extensive work is required to maintain the sustainable use of water. International Standards for materials, equipment performance, test methods, data interpretation and performance reporting of irrigation equipment developed by ISOITC 23/SC 18 play a vital role in providing solutions. ”
To find out more about ISO Environmental Management Standards and the work of the ABBS kindly contact the Antigua and Barbuda Bureau of Standards, Corner Redcliffe Street & Corn Alley, P.O. Box 1550, St. John’s, Antigua (W.I.) or Telephone 462-2424 or email: email@example.com.