Spa Plant Room for a Gulf Hotel Thermal Suite

Sauna Dekor Spa Solutions engineering team, Istanbul · project and press enquiries: Alican Aykaç, Managing Partner

Last updated: 5 November 2026

The figures come from manufacturers and published guidance: Condair’s installation manual for the Sigma steam generator, TechnoAlpin’s data for its SnowSky snow machine, the UK Health and Safety Executive’s guidance HSG282 on spa pools, and Sport England’s guidance on servicing pool buildings. Where a figure is written for a swimming pool rather than a spa, we say so.

Table of contents

• What goes in a spa plant room?
• Why do steam generators sit outside the main plant room?
• What does a steam generator need around it?
• Why does a Gulf spa plant room need cooling?
• How much space does water treatment take?
• What does a whirlpool add to the plant room?
• Where do the plunge chiller and snow room cooling go?
• What drains, doors and access does the room need?
• How do you add up the area of a spa plant room?
• Where should the plant room sit in the hotel?
• What does this look like in our projects?
• Frequently asked questions
• Sources

A hotel thermal suite plant room usually holds 5 groups of equipment: water treatment for the whirlpool and plunge pools, cooling for cold plunges and any snow room, steam generators for the steam rooms, power and control panels for saunas and showers, and the hot and cold water supply for showers.

Each group has a different master. Water treatment follows the pools and the health guidance that governs shared water. Cooling follows the refrigeration maker’s data. Steam generators follow the steam rooms, which is why they are often not in the main room at all. Sauna heaters and their control units are supplied by heater makers such as Harvia and EOS, and their contactor panels are wall-mounted in a dry place outside the cabins, as our note on sauna electrical requirements explains. The shower systems of the suite draw their hot and cold water from the same room.

Because the steam line is short. Condair’s installation manual for its Sigma generator asks for a steam hose no longer than 4 m, with a minimum bend radius of 300 mm and a steady slope. A steam room more than 4 m from the main plant room therefore needs its generator in a small satellite space beside it.

The limit is physical, not a matter of preference. Steam cools and condenses as it travels, and Condair allows for a pressure loss of about 100 Pa per metre of line and per 90° elbow. A long line delivers less steam and more water to the room. So we draw each steam room with its own generator position first, and only then decide whether that position can be part of the main spa plant room.

In a compact hotel thermal suite, the main room and the steam rooms are often adjacent, and one wall of the plant room backs onto the steam rooms. In a long suite they are not, and each steam room or pair of steam rooms gets a service cupboard behind it. On our steam generator page we show how generator and room are paired, and our page on custom steam rooms in Dubai shows the same pairing in a villa. All of our steam rooms run on Condair generators; the Sigma range covers 4 to 65 kg of steam per hour.

A Condair Sigma needs a solid wall, a floor drain, free space of 250 to 600 mm around its housing with 600 mm in front, and a drip-proof location, because the unit is rated IP20. Its back panel reaches about 60–70 °C in operation, so the wall behind it must not be heat-sensitive.

The water side is just as specific. Condair asks for a supply pressure of 1 to 10 bar and water with a conductivity between 125 and 1,250 µS/cm for the standard cylinder. The generator drains part of its water from time to time to control the mineral content, so a floor drain is mandatory; where none can be provided, the manual requires a leakage monitor that shuts off the water supply.

The housing itself is compact. The 3 Sigma sizes measure about 285 × 205 × 430 mm, 377 × 279 × 612 mm and 492 × 351 × 670 mm, with operating weights from 13 to 65 kg. What takes the space is not the unit but the clearances, the steam and condensate lines and the access a technician needs to change a steam cylinder.

Because the equipment has an upper limit and a Gulf summer can pass it. Condair specifies 1 to 40 °C and no more than 75% relative humidity around the Sigma. TechnoAlpin gives 35 °C as the upper operating limit for SnowSky. A plant room with hot pipes, pumps and chillers adds its own heat on top.

A plant room against an outside wall, or one ventilated with outdoor air, can therefore run above the limits that the manufacturers set, especially in summer. In Gulf hotels we ask for the spa plant room to be mechanically cooled or supplied with conditioned air, with its own temperature reading on the building management system. Condair’s commercial generators connect to building management systems through protocols such as Modbus and BACnet, so the generator and the room can be watched together.

Humidity is the second half of the problem. A plant room next to steam rooms and pools collects moisture from drains, tanks and small leaks, and 75% relative humidity is not a high ceiling. Extract from the plant room, sealed drain gullies and a dry floor are part of the design, not a maintenance task to be added later.

Sport England’s guidance for pool buildings puts the pool water treatment plant room at 15 to 30% of the water area it serves. On that basis, a 9 m² whirlpool and a 4 m² plunge pool, 13 m² of water in total, would need about 2 to 4 m² for their filters, pumps, balance tank and dosing.

The ratio is written for swimming pools, and a spa stretches it. A whirlpool has a small area of water but a high turnover, so its filters and pumps are large for its size. HSG282, the HSE’s guidance on spa pools, gives a turnover of typically 6 minutes for commercial spa pools with a high bather load and 15 minutes for lower loads. That is why we treat the 15–30% figure as a floor for spa water, not a target.

The same guidance adds what the figure leaves out. Chemicals are stored in a separate ventilated area, with bunding and an emergency drench, and the acid and chlorine stores need their own ventilation. Our guide to hydrotherapy covers why a small pool so often comes with a large plant room, and our page on swimming pool construction in Dubai shows the pools that this plant serves.

A commercial whirlpool adds a balance tank, filters, circulation pumps, a heater and a dosing system, and HSG282 expects all of them to be easily and safely reachable for maintenance. It also asks for about 80% of the circulation to be drawn from the surface, where most pollutants are.

The balance tank is the item that decides the room. HSG282 notes that it is generally located in the plant room, and asks that it is sized for the bather load, easy to inspect, clean and drain completely, and fitted with a removable lid or hatch. Sport England adds that pool circulation pumps should sit at the level of the bottom of the deepest water, so that they stay flooded.

Together these 2 rules often push the spa plant room down a level, or at least down to the base of the pool tanks. In a hotel where the spa sits on a podium slab, that means a plant room in the floor below or a recess in the structure, which has to be agreed before the slab is designed. This is the decision the spa consultant should be in the room for.

Both reject heat, so both need air or water to reject it to. We build cold plunge pools for water temperatures from 2 to 15 °C, and the chiller that does it gives off heat wherever it stands. TechnoAlpin’s SnowSky cooling system weighs 400 kg and can stand up to 50 m from the snow machine.

The 50 m allowance gives the designer a choice. The snow machine itself, 1,360 × 750 × 450 mm and 150 kg, sits at the snow room, while its cooling system can go to the main plant room, a roof or a service yard. TechnoAlpin gives the whole system a power consumption of 4 kW and a water use of about 11 litres per hour, at drinking water quality and 1 to 8 bar. A snow room runs at about −10 °C (TechnoAlpin).

The plunge chiller is placed by its maker’s data rather than by ours: its airflow, clearances and refrigerant lines decide where it can stand, and in a Gulf summer an air-cooled unit in an enclosed room needs a clear path for its hot air. Our page on cold plunge temperature explains the water side, our page on the ice bath in Dubai covers cold plunges in Gulf projects, and our snow room page the room itself.

A spa plant room needs a floor drain and a hose point, doors at least 1.0 m wide and preferably 1.5 m, locked against guests, and a clear route for replacing the largest item. Sport England sets these for pool plant rooms, with space for a workbench and manuals, and Condair makes the floor drain mandatory for its Sigma.

The largest item is usually a filter vessel or a chiller. Sport England recommends an external delivery door of 3.0 × 3.0 m for filter replacement in pool buildings; a hotel spa rarely gets that, but it needs an equivalent route through back-of-house corridors and service lifts. We check that route on the drawings with the real dimensions of the equipment, not with a generic clearance.

Add it up from the equipment, not from a percentage of the spa. List every unit with its footprint, add the manufacturer’s clearances and a working aisle, then add the water treatment allowance. 2 Condair Sigma generators of the medium size, for example, need about 1.5 to 2 m of wall.

That wall figure comes from the manual: each medium unit is 445 mm wide, with 250 to 400 mm of free space at the sides and 600 mm in front. The same method gives the floor area for a chiller, a snow room cooling system or a control panel from its own data sheet. Water treatment is then added at 15 to 30% of the water area, adjusted upward for whirlpools.

We do not use a single percentage of the spa area for the plant room, because 2 spas of the same size can carry very different equipment: one with a steam room and a sauna, another with a whirlpool, 2 plunges and a snow room. The list of rooms decides the plant room, which is why the wellness centre in Dubai we describe elsewhere began with the plant before the finishes.

Close to what it serves. Sport England asks for plant rooms to be located near the areas they serve, to shorten service runs and reduce losses, and Condair limits the steam line to 4 m. In practice that puts the main room beside or below the pools and small satellite spaces behind the steam rooms.

Access is the other constraint. Staff and contractors reach the plant room through back-of-house, never through the guest route of the thermal suite, and Sport England asks for plant room doors to be locked against untrained staff and the public. Noise from pumps and chillers also needs a wall or a slab between the plant and the relaxation rooms.

At the Diplomatic Club in Doha, completed in 2022, we built the pools, sauna, whirlpool and steam rooms of the spa and fitness floor. The whirlpool in the photograph above is the visible end of a system of filters, pumps and dosing, and the steam rooms run on Condair generators. Our Doha page covers our work in Qatar.

The Diplomatic Club spa shows how many separate systems a single club floor carries: heat for the sauna, steam for the steam rooms, treated and heated water for the whirlpool and pools. At Yelken Hotel in Awaza, where we built the hammam, sauna and steam rooms, there is no pool water to treat in our scope, so the plant behind those rooms is mainly steam generation and power.

Sauna Dekor has designed, manufactured and installed saunas, steam rooms, hammams, pools and cold plunges since 1987: 40 years of manufacturing in Istanbul, in our own facility in İkitelli OSB, with a team of 19 employees and 5,000+ projects in 41+ countries. We work under TS EN ISO 9001:2015, certificate no. 202025106. Our offices are in Istanbul (İkitelli OSB), Dubai (Latifa Tower, World Trade Centre), Bodrum (Bodrum Çarşı), Germany (Monheim am Rhein) and Boston (66 Long Wharf, Unit 4B). We also have representative offices in Haarlem and Doha.

We design and build the thermal rooms, pools and cold plunges, plan the plant room that serves them and install the equipment in it. We do not manufacture steam generators, chillers, snow machines, pumps, filters or dosing systems: our steam generators come from Condair, snow systems from TechnoAlpin, and any marking or certification of that equipment belongs to its manufacturer. The TS EN ISO 9001:2015 certificate is ours. On the work we deliver, the terms are a 24-month warranty on workmanship and manufacturing; 24-month manufacturer’s warranty on electrical and mechanical equipment; 5-year warranty on structure and waterproofing.

Typical arrangement, not a fixed rule: the final layout is set for each project.