The Ontario and other provincial Building Codes have minimum standards that have been established to ensure that new public pools are constructed to be safe and functional. Following construction, Health Departments are responsible for monitoring and regulating the operation of the pool. The entire content of the code is important, but some items really stand out. For example, strict adherence to the velocity of water moving through suction fittings like the main drains is really important. The velocity of water through main drains is dictated as not to exceed 1.5 fps (feet per second). This low velocity helps decrease the possibility that people might become entrapped or entangled by the main drain fitting.
Another really important factor is the turnover rate of the pool. For Class ‘A’ pools (a pool to which the general public is admitted), the entire volume of the pool has to be filtered and chemically treated every four hours. This ‘turnover rate’ provides some assurance that the pool water will be clean and safe for bathers to use. The Building and Health Codes are very important and have elements that work to ensure pools work really well and up to standards, most of the time. As with most rules, there are some exceptions that should be considered. An important question to consider is: When is it a good idea to do more than what the code calls for?
CLASS A & CLASS B POOLS
In Ontario for example, a Class ‘B’ pool (a pool operated on the premises of an apartment building with five or more units, a pool operated as a facility to serve a community of more than five single-family private residences, a pool operated on the premises of a hotel, a pool operated on the premises of a campground, a pool operated in conjunction with, a club or a condominium, a pool operated in conjunction with a day nursery, a day camp or an establishment for the care or treatment of persons who are ill, infirm or aged) is required to be designed in such a way that the circulation system exchanges the entire volume of the pools water once every six hours, or four times per day. Most of the time, this is totally acceptable, but there are times when it is not sufficient. At some resorts for example, the pools are shallow and the volume of water is small. This coupled with a very high usage, warmer water and bathers who may not shower as well as they should (especially children) can create a condition that makes the water quality very difficult to manage. We often oversize the circulation systems with larger than required pumps and filters in this instance and add secondary sanitation systems like UV to help ensure superior water quality.
The same is true of a Class ‘A’ pool. These pools are required to be designed to exchange the water in the pools every four hours or six times per day which seems like a lot, but again there are some exceptions. If the pool is a therapeutic pool with a higher percentage of elderly users, or users with either a physical or mental disability, there may be a higher risk of contamination by fouling, making it prudent to exchange the water more often and install UV systems. For pools like this we often design the mechanical system to exchange the water every two hours, or 12 times per day, or more.
Another important consideration is the filtration rate of the pool filter system. In all cases this is calculated by dividing the total flow of the circulation pump by the total surface area of the pool and is expressed as GPM/FT2 of filter area. For sand filters, most manufacturers call for a filtration rate of no more than 15 GPM/ FT2. For a pool that has a flow rate of 450 GPM, the total sand area should be no less than 450 GPM/ 15 GPM/FT2 = 30 FT2. This square footage can be achieved by either using one or two larger horizontal or vertical filters, or a ‘battery’ of smaller filters. Is a filtration rate of 15 GPM/ ft2 always enough? For a lesser-used pool with a lower-risk user, and a low bather load, the answer is probably yes, but in instances where there is a high bather load, it may make sense to lower the velocity of water through the filter to improve filtration even more. Sometimes it makes sense to oversize the filter so that the filtration rate is more like 12 GPM/ft2. The same thing can be done with other filter media like cartridge filters or DE (diatomaceous earth) filters.
UV SANITATION SYSTEMS
UV is a secondary sanitizer that effectively renders most bacteria unproductive (and therefore safe) as water passes through the device. UV units are not required by code for pools (UV is required for splash pads) or spas, but may be a really good idea to install anyway. Some bacteria are resistant to chlorine or bromine and can become the source of an infectious condition that can make swimmers sick. This can result in a severe and widespread illness outbreak that could have long term effects or even cause the death of a vulnerable individual. There could also be legal implications for the owner/operator of the pool. Even though the codes do not require it, putting UV systems on a high bather load or high risk pool is a smart and proactive change to make.
Finally, the codes are an effective way to improve the overall safety of pools across the community. As with all rules and regulations, not every scenario can be addressed. It is best to look at the particular conditions surrounding your pool and design it appropriately. Since there is no specific ‘rule book’ to help you decide when code requirements should be exceeded, it is best to consult an aquatic consultant or pool builder who has a long record of experience with a variety of public and private pools. These experienced companies will help you design, build or upgrade a pool that is safe and fun for your clientele.