When pipes are out of sight, you shouldn’t lose sight of these issues.
Plumbing is central to the success of any building, campus or facility design. When people go to live, work or play in a building, they need water to maintain and clean the building, prepare food and drink it.
It can be easy to think of plumbing as an afterthought as plumbing systems are usually hidden behind walls and just expected to work just like home. Out of sight, out of mind, right? In fact, all too often this tendency to pay insufficient attention to the design of piping systems leads to mistakes that can haunt construction work and ultimately require expensive adjustments to get them right.
What are the main considerations for building developers and building owners regarding plumbing systems? A few key areas to focus on will help ensure that your building is functioning as it should be from the start.
1. Under pressure
The most common plumbing problem has to do with water pressure. One of the most important goals when designing a water system for buildings is to ensure that there is adequate water pressure across the entire line, including at the furthest fixture. The larger the building, the greater the challenge of ensuring sufficient and consistent pressure in a structure. For a 25-story office building, this means that the water may need to travel at least 90 feet vertically while maintaining water pressure all the way to the end of the line. That is no small feat.
Wrapped in the pressure discussion is the question. How does a building, say a hotel that serves a conference center and is in high demand in the morning and evening, modulate to deliver the right pressure when demand rises?
It is imperative that your mechanical engineer properly sized your pump and control systems to provide adequate GPM and head pressure for this wide range of needs. The most common error we see with troubled field installations is a lack of proper equipment and controls that can respond to the wide variations in usage. Pumps that are too small, inadequate controls and inadequate pipe dimensions can all lead to costly remediation work for owners and building managers.
One of the main challenges is determining how much pressure is needed when the building is fully occupied. All designs start with the supplied city or well pressure and then design according to the needs of the building. Depending on the type of supply, this demand can vary greatly.
No two construction projects are the same, so mechanical engineers must understand the specifics of the building in order to devise the right approach to address the unique challenges and opportunities presented on the site.
For most buildings, water pressure is only an operational problem to be solved, albeit expensive. But in mission-critical operations, such as in hospitals or public safety facilities, buildings cannot afford to lose water pressure. Not only can this affect emergency services that need running water, but it can also lead to contamination of the water that does flow. For these buildings, water pressure is not only a matter of cost, it can also be a matter of life and death.
2. Drinkable water
If pressure and delivery is the most talked about piping system, water quality is directly behind it in terms of its effect on your building and the people who occupy it. Taste, hardness and maintenance by deadly bacteria are all important considerations in the development of a plumbing system.
Most jurisdictions provide the public with safe, potable drinking water, but it doesn’t necessarily taste good. In some areas, such as Florida, owners face challenging conditions, where solids and odors from their water can cause serious complaints from tenants. With the help of mechanical engineering teams, many are choosing to install building-wide water treatment systems that remove the contaminants from the water source and re-add minerals to provide a better experience.
Water hardness also plays a major role in water quality treatment from the perspective of the owner and developer. Hard water contains many dissolved minerals, especially calcium and magnesium. The harder the water, the more likely it is to fill water heaters, pipes and fixtures. Just one-hundredth of an inch scale built up in a heat exchanger can significantly reduce performance, from 20 percent to 45 percent (even more in extreme scenarios), increasing operating costs and affecting the overall lifecycle of your system. A simple treatment system, often in conjunction with the one that treats the water to taste, can alleviate this headache when considered in the design process.
Another important drinking water issue is legionella. Water is always treated as it enters the building, but if left in pipes for too long, the deadly bacteria can build up in those pipes.
Legionella must have very specific conditions to live, one is standing water and the other is a specific water temperature range. National sanitary best practice recommendations specify that water storage tanks (where water can stand for a while) remain at 140 degrees – a temperature at which legionella cannot survive – but be careful, this is not a minimum. Legionella can live in water both below and above that mark of 140 degrees.
The other important step is to make sure that your water systems, especially hot water systems, recirculate regularly. This will keep the water in your pipes from stagnating and allow the bacteria to develop. Simple, yet effective ways to keep your water systems safe.
3. Hard water
A third and final problem facing many buildings is hard water. Hard water contains many dissolved minerals, especially calcium and magnesium. The harder the water and the more untreated it is, the more likely it is to contaminate hot water heaters, especially tankless hot water heaters.
Just one-hundredth of an inch of deposit built up in a heat exchanger can significantly reduce performance, from 20 percent to 45 percent (even more in extreme scenarios), increasing operating costs and affecting the overall life cycle of your system. This can be an expensive problem to live with, minimizing the value of the dollars you use to operate your equipment. With this problem, you’re constantly throwing those dollars away. Depending on the size of your equipment, these may be just pennies off the dollar, but if you heat thousands of gallons of water a day, those pennies add up quickly.
Hard water can also lead to premature replacement of water heaters, balancing valves and other hardware. The bigger the building, the bigger and more expensive the solution.
When designing plumbing systems for new buildings or complexes, it is essential to test your water quality. If necessary, your MEP engineers can develop strategies to treat the water as it enters the building and to properly maintain the water heating tanks.
When developing a new building or complex, it is important not to consider plumbing as an afterthought. In addition to traditional plumbing considerations of how to build plumbing infrastructure and integrate it into the operations of the building, it is essential to pay attention to these three areas that are often missed. Water pressure and water quality play a major role in the perceived success of a project and can have a meaningful impact on the operation and operating results of a facility.
If not addressed correctly from the outset, it can lead to costly repairs or equipment replacement. It is essential for projects to rely on an engineer who understands these systems and uses them regularly to ensure your project is successful.
Tom Bernard is MEP Market Leader for WGI Inc.. He can be reached via [email protected]
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