30 HEALTH AND SANITATION
pipe for which Hunter’ s Curve would have called. While there were no upfront savings in municipal charges— service development charges were waived by the city for this project— Lansing counts among the project’ s virtues a performance gain and a decreased risk of illness for the vulnerable resident population. A larger diameter pipe would have posed a greater risk of biofilm development, and increased danger from waterborne pathogens, including legionellosis.
Reducing the risk of Legionnaires’ disease in domestic water systems is covered in ASHRAE Guideline 12 and ASHRAE Standard 188, which calls for additional protection for certain occupancies. Lansing categorises the Julia West House demographic to be at a higher risk than the average population.
“ People who have lived on the streets carry undiagnosed or uncared for health issues,” Lansing says, citing for example the connection of unsheltered sleeping adjacent to busy roadways and freeways with asthma.“ Housing is a foundational component of public health,” Lansing says.“ There is extensive evidence linking people with asthma to higher risks of Legionnaires’ disease and unhoused people are 24 % more likely to have asthma.”
While single family homes may not have the same scalability to demonstrate impressive financial savings compared to large apartment buildings, WDC’ s implementation in even the most basic housing design can affect beneficial shifts in behaviours.
“ Small diameter pipes allow shorter hot water wait times,” Lansing says. Residents are less likely to send water down the drain, waiting for a shower to heat up.“ It’ s an often-overlooked aspect of where water waste happens.”
From his vantage in Napa, California, Todd Kuchta of J. W. McClenahan has seen the WDC at work in student housing, including a 14-story building where the four-inch pipe called for by Hunter’ s Curve would have been challenging to conceal in a long corridor.
On Treasure Island, another of Kuchta’ s projects, a 20-story building has been sited on a former military installation. Water Demand Calculator calculations called for a four-inch pipe where Hunter’ s Curve would have called for as much as a 6-inch pipe, but Kuchta believes that a three-inch pipe would have handled the flow just as well.
“ We still overestimate how much we use toilets,” he says, explaining that Hunter’ s Curve essentially estimated every toilet being used every four minutes in a 250-unit building.“ With two people each