We ask Grok to review and provide a summary of the following pdf file titled "Class A Water Matters" on NSF/ANSI 55 and Class A and Class B UV Disinfection Systems. 

https://solmetex.com/wp-content/uploads/2023/09/Class_A_Water_Matters.pdf

We created this post because it is our experience that up to 50% of private well owners need a UV disinfection system and many times the wrong UV disinfection system is installed.   For city water users, it is not common to install UV disinfection because the water is coming from a community water supply that is treated and has a chlorine or disinfection residual, but in some cases this level of treatment is necessary. 

The Sponsor for this Article is Jase Medical
“Emergency Medications & First Aid Kits”

Summary of "Class A Water Matters" (Water Conditioning & Purification, May 2010) by Grok with additional comments by the Know Your H20 Team (red). This article, authored by Rick Andrew of NSF International, provides an in-depth look at ultraviolet (UV) disinfection systems for point-of-use (POU) and point-of-entry (POE) drinking water treatment, with a focus on the NSF/ANSI 55 standard. It explains the technology's role in inactivating pathogens and clarifies the differences between Class A and Class B systems, emphasizing why Class A certification is crucial for treating microbiologically unsafe water.

Key Concepts

• UV Technology Basics: UV light at 254 nm wavelength disrupts microbial DNA, preventing reproduction. It's chemical-free, effective against bacteria, viruses, Giardia, and Cryptosporidium, but works best on clear (non-turbid) water.
  
  
• NSF/ANSI 55 Standard: Certifies UV systems for safety and performance. It addresses design, dosage, alarms, flow control, materials, structural integrity, and labeling.

Table 1. Class A vs. Class B Systems.

Technical Requirements

• Dosage Verification: Bioassay tests confirm effectiveness at highest flow rates.
  
  
• Material Safety: Extraction tests ensure no harmful leaching; formulation reviews guide testing.
  
  
• Structural Integrity: Rigorous pressure tests (e.g., 240 psi burst for small vessels; 10,000 cycles at 50 psi for cyclic stress) simulate long-term residential use.
  
  
• Product Literature: Mandatory clear instructions, data plates, performance sheets, and replacement guides to inform users.

Importance and Benefits of Class A Treatment

• Public Health: Essential for homes relying on untreated sources, reducing waterborne disease risks without chemicals or taste changes.
  
  
• Regulatory Edge: Meets strict NSF criteria for efficacy and durability, building consumer trust.
  
  
• Limitations: Best for clear water; turbidity reduces effectiveness, requiring pre-treatment.  (Pretreatment may be needed for water that has a high hardness, elevated levels of iron / manganese, or scale forming water and additional water quality testing would be advisable.)
  
  

Conclusions

The article stresses that Class A systems offer robust protection for at-risk water supplies, while the NSF/ANSI 55 standard ensures transparency and reliability. It urges manufacturers to comply fully to avoid misleading claims, promoting UV as a vital, accessible disinfection tool. (Source:solmetex.com)

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End of AI generated Content

You may need a Class A Disinfection System

1. Well with with elevated level of total coliform (i.e., 1 or more colonies per ml)  with or without E. coli. and/or an elevated presence for heterotrophic bacteria (i.e., > 250 colonies per ml).

2. You may consider using a Class B UV disinfection system when you have well water or city water that has a total coliform count of not-detectable or less than 1 colony per 100 ml and/or a heterotrophic bacterial count of < 250 colonies per 1 ml. 

Common City Water Situations that Require UV Disinfection

1. A city water system that is having difficulty maintaining disinfection residuals.
   
   
2. The user is located near a dead-end in the water distribution system or part of a distribution network that has a lot of intermittent water usage.
   
   
3. A user that is experiencing issues or problems with bacterial regrowth in the their portion of the distribution system.  They may notice the water has a strange foul odor, back of toilet tank may have microbiological sheen or slimy coatings, and their water may have an off-taste. 

Always make sure to get your water tested.   Well Water  / City Water Testing Options.

Learn More about UV Disinfection