Water quality is key to an enjoyable experience at a waterpark, pool or spa. NSF International has addressed the need for increased safety of swimmers and recreational water users for more than 50 years through research, standards development, product testing, manufacturing facility inspections and product certification. Recent NSF research and development has yielded further safety requirements for evaluating and testing automatic controllers (ACs).
ACs are critical to water quality maintenance and public health. They measure, monitor and maintain water quality by controlling and adjusting disinfectant, acid and base feeding systems.
Most ACs are comprised of the
1A flow cell — the “test site” for sampling and monitoring.
2A chemical probe or sensor — the “detective” used to monitor control parameters.
3A display — the screen or graphical user interface to input values and visually check status.
4A controller — the “brain” that receives signals and data from the chemical probes or sensors, compares the latest readings to the set points, then sends signals to activate one or more types of equipment. Some systems link multiple AC units or enable wireless communication and review of system status.
Additional AC components required for proper function include chemical storage tanks, tubing, valves, wiring, flow switches, float/level sensors, chemical generators and mechanical chemical feeding pumps.
NSF International has developed nearly 80 voluntary American National Standards through a consensus-based process with input from industry representatives, public health/regulatory officials and user/consumer representatives. This history and commitment to the needs of all stakeholders produces robust criteria applicable to many industry products.
The requirements for ACs were developed through the NSF Joint Committee on Recreational Water Facilities with input of public health officials, product designers, manufacturers, users and facility operators. The committee used NSF’s ANSI-accredited development process to add AC requirements to NSF/ANSI Standard 50 — Equipment for Swimming Pools, Spas, Hot Tubs and Other Recreational Water Facilities.
The requirements for ACs were successfully balloted into NSF/ANSI 50 in 2009, and the first controller products were certified in late 2010. In 2012, national pool and spa construction codes, as well as public health and building codes, (T-24, Pt. 2, Vol. 2, California Building Code and the ICC-ISPSC) began to require AC products to be certified to NSF/ANSI Standard 50.
NSF 50 requirements for pool and spa products continue to evolve. Planned changes include revised requirements for safety inter-locks, life testing and common controller functions such as TDS, temperature, flow rate, salinity, turbidity, etc. It is likely that the requirements between the water quality test device and the AC will converge. There are plans to address sensor system requirements related to integrating flow switches and level sensors, which are important in water chemistry maintenance, chemical production and chemical tank level monitoring.
NSF scientists currently conduct the following evaluation and testing of ACs to NSF/ANSI Standard 50:
1Material safety and toxicology formulation review: A review of formulations, suppliers, and design
2Chemical resistance testing: A 100-day chemical exposure and analysis
3Life testing: Three systems for 110,000 cycles of actuation at full amp load
4*Performance operating conditions: Four increments between 0 percent to 100 percent operating range
5*Failure sensing and signaling: Mechanism, process, visual signal
6*Monitor display accuracy testing: Operational status and level, in units of measurement
7*Operational protection: Controller shuts off equipment outside set limits
8Evaluation of operation and installation instructions: Details of maintenance, installation, loads, ranges, etc.
9Product labeling, electrical and caution statements verification: Manufacturer name, address, equipment model, serial number, etc.
In addition to laboratory testing, NSF performs annual unannounced monitoring inspections of production facilities. During this visit, NSF reviews purchase, customer and shipping records. NSF meets with the technical staff involved in supply and production to discuss issues such as product changes and improvements that a manufacturer may want to make. Any software or hardware changes must be documented and reviewed by NSF technical staff to determine if the requested changes require testing and validation prior to NSF authorization.
NSF evaluation, testing, and certification are designed to confirm product functionality without constraining design. NSF’s logical and rigorous process of checks and balances helps the industry protect itself and grow safely. NSF ensures that products have been, and will continue to be, properly vetted to help you manage your residential or commercial recreational water facility.
*The controller shall meet the requirements above before and after the chemical resistance test.