The Model Aquatic Health Code: What You Need to Know

The Model Aquatic Health Code:

What You Need to Know

By Dewey Case

In 2020, the Council for the Model Aquatic Health Code (CMAHC) began its triennial process of reviewing and evaluating change requests submitted in 2019 for the upcoming edition of the Centers for Disease Control and Prevention’s (CDC’s) Model Aquatic Health Code (MAHC). This was a herculean task as 530 individual change requests were submitted. To make matters more challenging, this review process coincided with the ongoing coronavirus (COVID-19) pandemic, which has impacted people around the world.

CMAHC assembled a dedicated group of aquatic professionals, representing such sectors as public health, manufacturing, operations and design. This group gathered to review and debate the 530 change requests prior to October 2020, when all change requests were presented at CMAHC’s triennial Vote on the Code conference.

Following the conference, a 30day voting window was opened for CMAHC members to vote on change requests — the results of which will be considered by CMAHC’s Board of Directors with recommendations made to CDC for inclusion in the fourth edition of the MAHC, to be released in summer 2021.

This article includes highlights of the 2020 Vote on the Code results. While many change requests are minor — such as clarifying terms or creating more consistency among code sections — others are significant.

It is important to note that as of this writing, the process is ongoing. The CMAHC Board of Directors will convene in early 2021 to make recommendations for CDC’s review.

The Use of Cyanuric Acid and Isocyanurates

Very few things stir up heated discussion like the use of cyanuric acid (CYA). Whether one supports or is against the use of CYA, one thing is true: for many aquatic venues, CYA and the products that contain CYA (isocyanurates) are necessary chemical additions. The addition of this chemical, specifically in outdoor aquatic venues, helps stabilize and shield chlorine from degradation by the sun.

Since 2016, a CMAHC committee has studied and debated the use of CYA. As a result of the committee’s research, a novel model was created to identify risk with varying CYA levels. The model was highlighted in an article published in the journal Water (tinyurl.com/y49e3ld4), while its findings were presented at various conferences, including the World Aquatic Health Conference. Although significant debate surrounding use of CYAs continues, the research points to a CYA-to-chlorine ratio that does not exceed 45:1 as a best practice. Regarding the CYA change requests for the MAHC, the most significant is the modification to what is considered an imminent health hazard and grounds for immediate closure. This includes when the CYA-tochlorine ratio exceeds 45:1 and when the CYA level exceeds 300 parts per million (ppm), regardless of the ratio.

Harmonization Between the MAHC and ISPSC

Since its inception in 2018, a committee formed to address differences in the MAHC and the International Swimming Pool and Spa Code (ISPSC) has identified some discrepancies between the two codes.

It is important to note that these are not competing codes. The MAHC is a model code developed by CDC as a resource for authorities having jurisdiction (AHJ) to update their existing codes, or to adopt in whole or in part. Several AHJs have used the MAHC to update their existing codes, while many others use it as a guide for best practices.

The ISPSC is part of the family of international codes developed by the International Code Council, which has

wide adoption. The ISPSC provides minimum requirements for the design, construction, alteration and repair of residential and commercial pools, spas, hot tubs and aquatic facilities. Overlap exists between the MAHC and the ISPSC in the commercial design and construction space. As for the biggest difference between the two codes: the MAHC provides comprehensive guidance on all aspects of commercial aquatic venues, while the ISPSC currently focuses on construction.

The efforts to update the ISPSC are spearheaded by the Pool and Hot Tub Alliance. Harmonizing relevant aspects of the two codes provides more clarity for those who build pools. Changes were identified for the fourth edition of the MAHC, as well as for the 2021 update of the ISPSC.

One of the most interesting changes requested requires the inclusion of steps and handrails for sunshelves, as well as three feet maximum depth adjacent to the sunshelf. These changes will only be effective for new construction or in cases where a pool undergoes substantial renovations.

Emerging Novel Aquatic Venues

The aquatics industry is an everchanging beast. Every year, new products or concepts are introduced. While not new, surf venues and artificial swimming lagoons are receiving increased attention as more of these very specialized venues are being constructed. Although they are very large and share similar concepts with traditional pools, these specialized venues are radically different. Change requests were submitted that would have included these venues in the fourth edition of the MAHC. However, when it came time for CMAHC’s technical support committee and technical review committee to evaluate these change requests, additional questions were raised about these venues. The questions resulted in an inability to refine the change requests and a recommendation against adopting them at this time.

CMAHC and CDC will spearhead efforts to develop guidance for these unique venues that can be used by pool inspectors and operators, which will result in more change requests for the next cycle of MAHC changes. CDC guidance is slated for release by Memorial Day 2021.

Ventilation Systems for Indoor Aquatic Venues

The sometimes-stagnant air and oftentimes pungent aroma of chloramines at indoor aquatic venues have spurred discussion at swim meets, swim lessons and many aquatic conferences. Several change requests were submitted via the CMAHC Indoor Air Quality ad hoc committee. These changes include: • Limiting air velocities to 30 feet per minute • Updating code references to the latest version of the American

Society of Heating, Refrigerating and Air-Conditioning Engineers • Updating air handling requirements for venues with stadium seating to improve air quality with an increased focus on moving air across the surface of the water • Research continues to validate that the most concerning air quality tends to be at the water’s surface. By moving more air across the surface and using methods to capture it, a significant amount of disinfection byproducts can be eliminated. This leads to benefits to the user’s experience and health as well as equipment life.

Interactive Spray Features

interactive spray features provided several change requests, the most significant regarding the use of ultraviolet (UV) light as a secondary disinfectant system. It is no great secret that the specific usage and dynamics of an interactive spray feature places users, overwhelmingly children, at a higher risk of fecal-based recreational water illnesses. Of specific concern in these type of venues is Cryptosporidium. The benefits of using UV light to lower the risk of Cryptosporidium are well known. Among these requested changes is a requirement that all interactive spray features be fitted with a UV light system designed to treat 100 percent of the recirculated water. This would not apply for pass-through systems where potable water is used, then drained into the sewer system.

Check Your Drain Covers!

While not an update to the MAHC specifically, I would be remiss in not reminding the community to check your drain covers. In 2008, the Virginia Graeme Baker Pool and Spa Safety Act (VGBA) was passed by Congress. It goes without saying that this law had ripple effects throughout the entire aquatics industry. Manufacturers worked to meet the new requirements and create the supplies, so that facilities could meet the implementation deadline. Designers and builders had to swiftly change practices to ensure compliance for pools in varying phases of construction. Service companies had to scramble to make sure their commercial accounts were going to be compliant. And many aquatic venues incurred great expense to retrofit their venues to achieve compliance, especially those that were from older construction with unusual drain configurations.

Flash forward to 2021, and VGBA is now slightly more than 11 years