Architects today are creating some unusual building designs in order to capture the imagination of their clients and the attention of the public.

The initial concept of many of these buildings can present unique challenges to the plumbing engineering design, which is required to ensure function follows form.

One of the aims of World Plumbing Review is to provide readers with an inside view of a collection of the most interesting and challenging projects from around the world as we talk to the engineers who are tasked with making these buildings ‘work’.

In the Brazilian city of Sao Paulo, a spectacular example of upmarket boutique accommodation designed by Brazil’s Ruy Ohtake forms an inverted arc flat on top and supported at each end by concrete pillars 82 feet (25m) high.

The 215,000 square feet (20,000m²) constructed area of the appropriately named Hotel Unique (otherwise known as the Watermelon Hotel) consists of six floors, 95 rooms, two restaurants, pools and a gymnastics academy. On the roof is a presidential suite complete with gymnasium and garden, as well as the Sao Paulo Sky restaurant and a swimming pool.

A full floor – which covers 54,000 square feet (5000m²) and is almost 20 feet (6m) high – is designed for events, conferences and exhibitions, and it can accommodate 1200 people.

Of the 95 rooms, only four are on the narrow first floor, and the top floor has 30 rooms that benefit from sweeping city views. Rooms at the end of corridors on each level feature a wooden floor that curves into the wall to take account of the outer arc.

All hydraulic and mechanical services for Hotel Unique were designed by the Sao Paulo consultancy MHA Engineering. MHA civil engineer Marcia Brandao Da Silva says that from the outset there was a strong focus on utilising the most modern technology and maximising clientele comfort.

“The aim was to construct a hotel that is different and could become a ‘postcard’ for Sao Paulo, not only for its facade but also for its infrastructure,” she says.

“The water reticulation system utilises PEX flexible polyethylene pipe connected to a manifold that is connected to cold and hot water risers in the central services shaft. This PEX system is very advantageous from a labor point of view because the material is light and can be easily transported and installed.

“Water is distributed directly to consumption points without intermediate connections, and all tubing passes inside a dry wall to facilitate maintenance without damaging the masonry. The whole plumbing system was pressurised about 2kgf/cm² (28.4psi), and the fire protection system was also pressurised and supplied from the same tank reservoir that is used for consumption. Due to the ceiling height, side-wall sprinklers were selected instead of a standard ceiling system.”

Water to feed the 4230 cubic feet (120m3) sprinkler system and similar capacity fire hose system is stored in the hotel’s 12,700 cubic feet (360m3) reservoir. Both systems use two kinds of pumps: jockey pumps to maintain the pressure at the wet standpipes, and fire pumps to provide pressure in the system when it drops below a preselected value.

“In Brazil there are codes relating to the design and installation of these systems,” Da Silva says.

“All drawings must go to the Fire Department for approval before installation proceeds. When installation is completed, the Fire Department carries out an inspection of the building.”

Hot water is provided by two operational gas heat exchangers in a manifold format, and a third heat exchanger is held in reserve. Recirculation pumps enable the water to be maintained at the required temperature at outlets.

The mains water supply is supplemented from an artesian well underneath Hotel Unique.