Following a devastating fire, Riverhills Health Club was rebuilt around its retained swimming pool shell. NSP transformed the aquatic facilities with redesigned commercial hydraulics, filtration and treatment, plus new deck-level spa and vitality pools. The result is a calm, high-quality hospitality environment delivering improved water quality, reliability and member experience, which quickly supported a full new-member allocation.

Riverhills deserves recognition because the project succeeds on two very different levels. For members, it is an inviting place to swim, recover and relax. For the operator, it is a carefully engineered commercial facility capable of delivering dependable water quality and performance throughout the working day.The fire gave Mosaic an opportunity to reconsider what the aquatic area should contribute to the wider health club. The aim was not simply to reopen the former pool, but to create a destination that would strengthen the membership experience and encourage visitors to spend more time using the club’s wellness facilities.The original 16m pool shell became the foundation of the new environment. Retaining it preserved a serviceable part of the building and avoided unnecessary reconstruction, but doing so required considerable ingenuity. Its former residential-scale circulation equipment was removed and replaced with a new commercial system. Seven returns, eight low-level suctions, deep-bed filtration, UV treatment and automatic chemical control now support a verified flow of 100m³/h and an approximate 1.4-hour turnover.The member experience was broadened through two new deck-level facilities. The circular spa offers a so

The overall theme was inspired by renewal: preserving the original swimming pool shell following the devastating fire while creating a completely new aquatic experience appropriate for a modern, premium health club and spa. Mosaic wanted the rebuilt facility to feel calm, welcoming and contemporary, while performing reliably under the demands of commercial operation. The pool was therefore considered not as an isolated facility, but as the centrepiece of a wider member journey incorporating swimming, hydrotherapy, relaxation and wellness. NSP became involved at the first design meetings in autumn 2023 and worked collaboratively with Mosaic, Cadman Construction, the architect, structural engineer and wider project team. NSP was responsible for the aquatic design and systems serving the retained swimming pool, new circular spa and bespoke vitality spa. The natural colours, tiled surfaces, timber detailing and architectural lighting formed the wider project palette. Within this environment, NSP developed the aquatic layout, hydraulics, filtration, water treatment, balance-tank arrangements and integration of the new spa and vitality facilities. The objective was to ensure that the technical systems supported the atmosphere rather than

The Riverhills aquatic facilities comprise a refurbished 16m swimming pool, a new 3.6m round deck-level spa and a bespoke 5.35m × 4.15m deck-level vitality spa. Each facility has dedicated commercial filtration, circulation, heating, UV disinfection and automatic chemical control. NSP designed the aquatic installation in accordance with the PWTAG Swimming Pool Water guidance and Code of Practice, HSG179, BS EN 13451 Parts 1 and 3, and BS EN 15288 Parts 1 and 2. Equipment was selected to provide consistent water quality, resilience and straightforward operation within a busy health-club environment. SWIMMING POOL The retained deck-level swimming pool measures 16m × 7m, with a constant depth of approximately 1.2m and a stated operating volume of 140m³. The former system had been substantially undersized for commercial operation. NSP completely redesigned the circulation system to deliver improved distribution of treated water and achieve the client’s required one-to-two-hour turnover. The completed hydraulic installation includes: * Seven new return inlets. * Eight new low-level suction points. * One dedicated vacuum point. * New underground and plant-room circulation pipework. * New manifolds, valves and isolation arrangements. * Connection to a newly constructed concrete balance tank. * Automatic water-level control and pump-protection sensors. * The ability to take 100% suction from either the swimming pool or balance tank without compromising the required circulation rate. * Replacement white LED underwater lighting using the retained pool niches. The final commissioned flow was verified at 100m³/h. Based on the stated 140m³ pool volume, this provides an approximate turnover of 1.4 hours. Filtration is provided by two Certikin SLX1800-30P commercial deep-bed filters. Each vessel is 1.8m in diameter and rated at up to 76m³/h. Their bobbin-wound fibreglass and polyester-resin construction provides durability and corrosion resistance within the commercial plant-room environment. At the commissioned total flow of 100m³/h, approximately 50m³/h passes through each filter. This represents an approximate filtration velocity of 19.6m³/m²/h, allowing effective filtration without operating the vessels at their maximum rated capacity. Circulation is provided by three 5.5kW commercial centrifugal pumps with integral strainers. Two pumps provide the normal duty arrangement and the third provides installed standby capacity. Regular rotation of the duty and standby pumps equalises running hours while allowing the pool to remain operational if one pump requires servicing. The pumps incorporate composite bodies, stainless-steel shafts, bronze impellers and stainless-steel strainer baskets. These materials were selected for their corrosion resistance, strength and suitability for continuous commercial operation. Primary treatment comprises commercial UV disinfection with an automatic wiping system, supported by sodium-hypochlorite dosing for the required disinfectant residual and sulphuric-acid dosing for pH correction. Monitoring and dosing are controlled through a Bayrol Compact PM4 controller. Automatic chemical control was essential within the health-club setting because water quality must remain consistent despite changing bather demand. UV treatment supports microbiological control and assists with the reduction of combined chlorine, contributing to improved water and air quality for members and staff. Pool-water heating is provided through an EJ Bowman FG100-5115-2T titanium tube-stack heat exchanger with a stated duty of 76kW. Titanium was selected for its corrosion resistance and suitability for chemically treated pool water. CIRCULAR SPA The original spa was replaced with a bespoke 3.6m-diameter round deck-level spa manufactured by GMT Spas International. Deck-level construction provides continuous surface-water removal and allows the operating level to remain consistent as bathers enter and leave. The spa has internal dimensions of approximately 2.6m × 2.6m × 0.9m and an operational capacity of approximately 2,950 litres. It was designed for up to 11 users per session, equivalent to a design throughput of 33 bathers per hour. The spa compilation includes: * 42 massaging water jets. * Four commercial 200 GPM suction fittings with stainless-steel covers. * Two return inlets. * Four 4-inch overflow-channel outlets. * One white Astral LumiPlus Micro LED light. * A 2-inch water manifold. * A 1.5-inch air manifold. * Fourteen adjustable supporting feet. * Curved social seating and stepped access. The filtration system was designed for a flow of approximately 33m³/h and a six-minute turnover of the operational spa volume. It incorporates a 1.2m-diameter commercial deep-bed laminated-polyester filter and a 2.2kW centrifugal circulation pump. Separate feature pumps and air systems operate the hydrotherapy jets without diverting or reducing the required filtration flow. This separation allows the spa features to be switched according to member demand while maintaining continuous water treatment. Dedicated treatment comprises UV disinfection, automatic sodium-hypochlorite dosing, automatic pH correction and a Bayrol Compact PM4 controller. Heating is provided by an EJ Bowman EC100-5113-2T titanium heat exchanger with a stated duty of 27kW. The spa operates at approximately 37°C. VITALITY SPA The bespoke deck-level vitality spa was manufactured by GMT Spas International and measures approximately 5.35m × 4.15m × 0.9m nominal depth. It provides a contrasting wellness experience through varied seating positions, hydrotherapy jets and flowing-water features. The vitality spa was designed for up to 20 users per session, with a design throughput of approximately 60 bathers per hour. Its technical compilation includes: * 85 non-adjustable mini hydrotherapy jets with stainless-steel escutcheons. * Four poly-jet returns with stainless-steel escutcheons. * Twelve commercial 200 GPM suction fittings with stainless-steel covers. * Four 4-inch overflow-channel outlets. * Three white LED spa lights with stainless-steel escutcheons. * Two A316 stainless-steel cannon jets with bespoke mounting plates. * Jet pipework terminating in a 2-inch water manifold and a 1.5-inch air manifold. * Integrated upright and reclined hydrotherapy seating. * A full stainless-steel supporting framework with adjustable feet. * PU foam insulation to the GRP shell. * Twin flexible modular overflow grating. * A fully tiled finish comprising 95% Jungle MT 5703 and 5% Satin Gold 952 tiles, finished with epoxy grout. The filtration system was designed for a flow of approximately 29m³/h and a nominal 30-minute turnover. It incorporates a 1.05m-diameter commercial deep-bed laminated-polyester filter and a dedicated 1.5kW centrifugal circulation pump. The filtration, jet, air and cannon-feature systems operate through separate circuits. This maintains the required treatment flow irrespective of which guest features are operating. Water treatment comprises UV disinfection, automatic sodium-hypochlorite dosing, automatic pH correction and a Bayrol Compact PM4 controller. Heating is provided through an EJ Bowman EC100-5113-2T titanium heat exchanger with a stated duty of 27kW. The vitality spa operates at approximately 34°C. BALANCE TANKS AND CONTROLS Formed concrete balance tanks were adopted following coordination between NSP, the architect, structural engineer and construction team. Cadman Construction formed the tanks, while NSP set out and installed the aquatic penetrations during the reinforcement and formwork stages. Accurate positioning was critical because the penetrations could not be moved after the concrete was poured. NSP also installed water-level sensors controlling automatic top-up, circulation-pump protection and the associated filtration functions. The filtration, feature, heating, dosing and water-level systems are controlled through purpose-built, floor-mounted electrical panels. These were factory assembled and pre-wired before delivery, improving reliability and presenting the club’s operators with a clear and manageable control arrangement. PROBLEMS OVERCOME The first challenge was introducing a completely new commercial circulation system into the retained swimming-pool shell without damaging or undermining it. Excavation and penetration work were completed in controlled sections. Each limited area was excavated, the new fitting and pipework installed, and the section backfilled and stabilised before work progressed. This method allowed seven returns and eight low-level suction points to be incorporated while protecting the original structure. The vitality spa had originally been programmed for installation before completion of the roof. Procurement delays meant that this access route was no longer available. Its four large sections were therefore carefully manoeuvred through a window opening and assembled inside the completed building. NSP and Cadman Construction developed the revised access, handling and assembly method together. The aquatic plant-room footprint was also reduced during construction when additional M&E equipment encroached on the allocated space. NSP reconfigured the filtration, circulation, heating and treatment equipment within the remaining footprint while retaining hydraulic performance, suitable isolation arrangements and reasonable maintenance access. COMMISSIONING AND OPERATION Each system was tested and operated continuously under working conditions before final commissioning. NSP balanced the circulation systems, verified the swimming-pool flow at 100m³/h and confirmed the operation of the filtration, heating, dosing, water-level and safety controls. Mosaic’s nominated staff received practical operator training, maintenance information and handover documentation. NSP has continued to provide technical and aftersales support and has subsequently completed the first annual service and balance-tank clean. The resulting installation combines the appearance expected from a premium health club with the resilience, water quality and maintainability required from a commercial aquatic facility.

Newson Swimming Pools