Electrical and lighting
Early collaboration between the electrical contractor/engineer and the pool designer will ensure the proper pool equipment is specified, such as pool pumps, heaters, and whirlpool jets. The specifications should not only address pool health regulations and general code requirements, but also include considerations about energy efficiency and maintenance. Energy-efficient equipment may help offset the owner’s costs and help minimize maintenance scheduling in the long term.
Bonding
While proper specifications and electrical connections for the pool system are important, electrical safety should not be overlooked or minimalized. The pool contractor and electrician should be well versed in electrical bonding and grounding methodology. Unlike physical safety elements, such as non-skid walking surfaces or pool fences, electrical safety like bonding and grounding occasionally take a back seat. All metallic components associated with the pool structure should maintain equal resistance. For instance, pool ladders must be electrically interconnected (bonded) and grounded to the earth. Additionally, structural and pool engineers should ensure structural steel reinforcement is bonded. Typically, a detail is incorporated where electrical and metallic components of the pool are joined with a wire to form a non-resistive path between them. This is to prevent an electrical potential from existing. The goal of bonding is to connect, contain, and prevent the transmission of electrical voltage that would endanger a life or damage pool equipment. Bonding should not be an afterthought.
Grounding
Analogously, the goal of grounding is to ensure the bonded pool components redirect harmful excess electrical current to the ground and away from pool equipment and life. The pool’s electrical network and electrical panel must be grounded to dissipate excess electricity. Without a proper grounding system set in place, people or pool equipment could become the conductor. Without both bonding and grounding, the risk to life safety is too high and the repairs will be a costly and timely endeavor.
Lighting
Ambient lighting specifications and layouts tend toward the vision of the designer. However, certain building codes and local municipalities have governances to protect local wildlife. If the client wants lighting available for night swimming, then certain requirements by governing bodies need to be met, which includes those imposed by the health department. Early and frequent coordination will help promote safety and performance, while maintaining aesthetics.
Exposed concrete—garage
It may not exist in all configurations, but the underbelly of an elevated rooftop pool structure may occupy a garage structure below. Cars exhaust various toxic (i.e. carbon monoxide) and non-toxic gases (i.e. carbon dioxide [CO2]). Governing bodies within the mechanical building code and/or industry standards such as those set by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) have mandated venting requirements for the design of a garage that addresses the carbon monoxide emitted from vehicles. However, the CO2 exhausted by vehicles idling or traveling within the garage can have an effect on the concrete structure. Carbon dioxide can react with freshly placed concrete to produce a soft chalk residue on the surface through a chemical reaction known as carbonization (production of calcium carbonate). Carbonation of reinforced concrete is a form of deterioration and contributes to the corrosion of reinforcement. Other contributors to the corrosion of embedded steel are oxygen from the atmosphere and the moisture from humidity or leaks from the pool above. Depending on the conditions, exposed and unprotected concrete may require an anti-carbonation coating to protect against the ingress of CO2 and other deleterious elements, while still allowing the concrete to breathe.
Conclusion
Early coordination between design professionals and the construction team is necessary to put preventative measures in place that will extend the pool’s life, maintain the structural integrity of the pool, avoid imminent danger to personnel, prevent damage to the pool and property below, and unnecessary future repairs.
The pool system is complex, but attention to details, specifications, and the interaction between trades can yield a safe, functional, and beautiful rooftop amenity pool. Waterproofing is symbolic of those collaborative relationships. Allocating sufficient preparation to the waterproofing application is not unlike the prep required at the start of the pool design. An inadequate approach can lead to failures in the structural integrity or damage to the pool and property below.
Patrick St. Louis, LEED GA, is a project director with Thornton Tomasetti (TT) in the Fort Lauderdale, Florida, office. St. Louis has been with TT for over eight years with a primary focus on forensic architecture. He has a bachelor’s degree from Florida Atlantic University. St. Louis is reachable via email at pstlouis@thorntontomasetti.com.
Lauren Millman, PhD, PE, is a senior project director with Thornton Tomasetti (TT) in Fort Lauderdale, Florida. Millman has been with TT for over seven years and specializes in forensic structural and materials engineering. She has a bachelor’s degree from the University of Florida and master’s and doctorate degrees from the University of Miami. Millman can be reached via email at lmillman@thorntontomasetti.com.
