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 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
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
Additional AC components required for proper function include
chemical storage tanks, tubing, valves, wiring, flow switches,
float/level sensors, chemical generators and mechanical chemical
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
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
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
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
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
*The controller shall meet the requirements above before and after
the chemical resistance test.