Although remarkable advances continue in medical science, surgical procedures and patient care, hospitals can still be dangerous places to stay.

This is well demonstrated globally by the increasing number of patients contracting diseases they didn’t have when they entered hospital.

In consultation with readers, WPI decided it would be of value to the industry to compare how plumbing designers globally are tackling onsite plumbing issues in the everyday construction of new hospitals of varying sizes in several countries.

There was no intention to turn this into a competition. Rather, the aim is to note similarities or differences in how various design and practical plumbing problems are solved. Sharing information is the central objective of this magazine.

Along the way we discovered some interesting ideas and solutions that will be valuable to readers working on similar projects in future. Our appreciation goes to the plumbing engineers/designers who helped us with this challenging editorial task.

Doutor Arnaldo Hospital, Brazil

In the Brazilian city of Sao Paulo, construction of the new general-purpose Doutor Arnaldo Hospital, with 733 beds, has been completed at a cost equivalent to US$150 million. The hospital consists of 28 floors, four of which are below ground level.

Hydraulic and mechanical services for the project were designed by the Sao Paulo consultancy MHA Engineering– including cold and hot water systems, fire hydrants and sprinkler systems, stormwater systems, medicinal gases, mains gas reticulation and diesel fuel systems.

According to MHA civil engineer Marcia Brandao Da Silva, challenges were confronted in designing and installing the hydraulic and mechanical services to fit with the architectural design of the building.

“The biggest difficulty with this project related to the ribbed slab structure and sewer system that was already in place,” she said.

“We spent a lot of time liaising with the architecture team and changing the position of bathrooms and sinks in order to provide effective access to the sewer below.

“Another problem was the restricted size of the ceiling areas, which meant that special attention had to be given to ensuring that the large volume of installations could be accommodated in the space available.

“An all-copper potable water reticulation system was installed together with seven connected storage reservoirs fed from the public system by pumping to the top reservoir. Total capacity of the reservoirs is 2.2ML (581 million gallons), and the top reservoir also has a 170m3 (45,000 gallons) reserve for fire service purposes. Each reservoir has two independent cells to enable maintenance without shutting down the system.

“All potable water is chlorinated in the public supply system before being filtered on site, but backflow prevention devices are not installed. As part of the Pura (Rational Water Use) Program, drain water from the air-conditioner towers is collected and returned for reuse in the same system. In addition, water-saving toilets with a 6L (1.6 gallons) flush are installed, together with flow restrictors in each faucet and shower. Under the Brazilian plumbing code, a maximum pressure of 40mca is specified for hot and cold water.

“The central flow and return hot water system is installed on the second floor below ground. Because of the height of the building there are three separate systems to provide pressure control – one each for high, medium and low pressure – and one for the kitchen and employee changing room.

“The hot water system consists of four storage tanks (two each of 3,000L and 5,000L, or 790 and 1,320 gallons) and three Raypak water heaters capable of providing 8,000L (2,115 gallons) per hour. Fabrimar thermostatic mixing valves (TMVs) are installed in the bathrooms to control hot water temperature, and Tour Andersen TMVs are used in the distribution lines to balance the system.

“About 27km (17 miles) of cast-iron pipe is installed at the hospital for the wastewater and stormwater collection systems. All wastewater is discharged to the sewer main for treatment at the public wastewater treatment facility. Stormwater is collected from the roof via a Saint Gobain Epams system and transported by gravity to the public sewer mains.

“An important part of the total project was the installation of a medicinal gases delivery system to the preparation rooms, surgery room, intensive care unit and internation rooms. Components of the system included all-copper piping together with 4,300 points to deliver nitrous oxide and oxygen, plus points for compressed air, vacuum and CO2.”

Da Silva says designing plumbing services for a hospital is very satisfying, but it requires a strong continuing focus to ensure all services will be efficient and reliable. This includes the continuing availability of the MHA team in case any final adjustments to plumbing-related installations are needed after the project is finished.