In the previous post we discussed the importance of accurate water supply analysis when looking at a new development. In this post we will look at more details on public water systems, how they are designed and operated, and what impacts these have on the water supply available for a new development.
The public water system consists of all the components necessary to supply water to our homes and businesses. This can include the raw water source, treatment system, storage tanks, pumps, piping and other components that deliver water to the customer. While all these components are critical to delivering water; when looking at an existing water system’s ability to supply water for a future development, the most important aspect to understand is how the water provider maintains pressure on their system, as this typically has the biggest impact on the water supply for a new development.
At the most basic level, water departments typically maintain their system pressure or hydraulic grade in one of two ways.
The first and probably most common is with an elevated storage tank(s), commonly known as a water tower. With this arrangement, the water system “floats” on the level of the water in the tank. The tank elevation and the water level in the tank set the system pressure. Pumps either at a water treatment plant, or a booster station are operated based on tank level. When the level drops to a certain point, pumps are brought on line to refill the tank. Larger systems with multiple pumps may bring on pumps in a staggered arrangement, with the first pump coming on at a certain water level and additional pumps brought on if the level in the tank continues to drop. On some systems, the pumps deliver water directly to the tank; however it is more common that the pumps discharge into the distribution system which, when pumping capacity exceeds system demand, will fill the tank indirectly. Appropriately, this method is called an indirect pumping arrangement. Continue reading “What You Need to Know: Water System Operation” »
Every jurisdiction has fire protection codes and requirements for new construction and remodels. Many require only that you follow the International Fire Code and have signed sealed hydraulic calculations, but others have their own requirements.
Alternatives in Engineering can help you with signed sealed hydraulic calculations and any unique requirements a jurisdiction can throw at us.
Here are some examples of unique requirements around the country:
City of Austin Fire Protection Rule requires the following:
For hydrant flow calculations, follow Appendix B of 2012 IFC but limit reduction of fire flow to 50% for certain building types
Accepted “C” values for calculations are 110 for PVC & Copper 80 otherwise
Austin Water also requires General Construction Notes and project information on drawings.
While seemingly a small part of the overall scope of a large development, accurate water testing and modeling of infrastructure to support new development is critical to ensuring adequate water supplies are available without excessive costs.
A complete water supply analysis for a new development consists of three critical parts, testing and analysis of the pubic supplies, accurate estimations of the water needs of the development, and proper modeling of the water infrastructure associated with the development.
Determining the capacity of the existing water system
The first step is to determine the capacity of the public supplies. This generally begins with obtaining flow test data. Performing a hydrant flow test is a relatively simple procedure, and many jurisdictions will provide this information for free or for a minimal charge, but often this low-cost option comes with a hidden expense. Many of the public personnel that perform flow testing on their system fail to understand the importance of the flow test data, tests are performed on the incorrect hydrants, an inadequate amount of water is flowed compounding errors, and the accuracy of these tests is often of concern as low cost, or poorly calibrated gauges are commonly utilized. Continue reading “What You Need to Know: Water Supplies for New Development” »
How to engage girls in STEM is a hot topic these days. As a woman-owned and operated business; we feel it is important that we are part of the conversation. In honor of Introduce a Girl to Engineering Day, I recently sat down with one of our engineers to discuss why she chose engineering and what suggestions she has for future engineers.
Nancy Epstein graduated from the University of MO-Rolla, now Missouri University of Science and Technology (S & T) in 2000 with a degree in Mechanical Engineering. She has been part of the AIE team since 2015.
Thanks for sharing your knowledge and passion for engineering, Nancy!
First, can you explain a little about what you do at AIE? When a developer or civil engineering firm is considering a building project, a sprinkler system is required. This system usually has water flow and pressure requirements. I work for a company that does the testing and calculations to determine if there will be sufficient water pressure at the site. If there is not sufficient water, the project will require a fire pump and/or water tank. Both items are very expensive and the developer will have to include those numbers in the project budget. Our first step is to schedule a test with the city water or fire department. Next, we do some research about the water lines around the site and determine where to test. I travel to the site and meet with our contact and conduct the test. When I return to the office, we do more research about the water system, then calculate and compile a report stating what water pressure and flow rate will be available at the site. That way, the final occupant of the building will have third party confirmation that they will have what they need for fire protection at the end of the project.
What made you decide to go into engineering? When did you know you wanted to be an engineer? As a kid I liked finding out how things work and I was obsessed with cars. More practically, in high school English was not my thing. I think I knew I wanted to be an engineer as a ninth grader.
What were your favorite classes ingrade school and high school? I really liked science. I had great HS Physics and Chemistry teachers. Those were my favorites. Orchestra was another favorite and I loved to read books.
What was the ratio of women to men in your engineering program? (Assuming there were more men than women, what was that experience like?) At University of Missouri at Rolla, there were five guys for every girl. I think the odds were a little worse in Mechanical Engineering. In one class, I was the only girl. That’s just the way it was. Generally, I wasn’t treated any differently at school. It was good preparation for industry. On the bright side, it was really easy to find a date.
How many years have you worked in your field? I have worked in engineering for eighteen years, quality control, manufacturing, and fire protection.
Can you describe your typical day and your favorite thing about your day? I’ll describe a typical week. I spend about one day a week traveling and testing, then I spend the remainder of the week in the office doing calculations and research and generating a report from the test results. I really enjoy traveling and testing outside. Many of our jobs are in Florida and Texas, and it’s nice to go someplace warm in the winter.
It has been 11 years since the day nearby residents say they “felt the ground shake.” Seventeen people were killed in what is still considered the nation’s second worst oil refinery disaster. On July 23, 1984, the Union Oil Company Refinery experienced an explosion that sent a 34-ton tower flying into a small field just beyond nearby houses. Around 6 p.m, a worker had noticed a hairline crack in a high pressure tower with gas vapors escaping from it. The worker tried to shut the tank down, but the vapors ignited from an unknown source before he was successful.
Consequently, much of the refinery was engulfed in flames. A second explosion Continue reading “On this Date in History: July 23, 1984” »
Picture on left: Wet System with Black Steel Pipe, Accumulation of Solids and Sludge due to Oxygen
Picture on right: Dry System with Galvanized Pipe, Oxygen Corrosion Has Breached Zinc Layer and Attacked Base Black Steel
The Role of MIC in Fire Sprinkler System Corrosion
You may have heard the term “MIC” used in reference to corrosion problems in fire sprinkler systems, as it has become synonymous with all general corrosion activity in sprinkler systems. MIC, which stands for microbiologically influenced corrosion, is a very specific type of corrosion caused by bacteria. Over the past several years many practitioners in the fire sprinkler industry have over-emphasized the role that bacteria play in causing corrosion in a fire sprinkler system while under-emphasizing the predominant role that oxygen plays in the corrosion that occurs in these systems. Continue reading “The Role of MIC in Fire Sprinkler System Corrosion” »
101 Years Ago Today
Today marks 101 years since the deadliest fire in our hometown city, St. Louis. The quick-spreading fire killed 30 men and destroyed the seven-story Boatmen’s Bank building at Washington Avenue and Fourth Street. Boatmen’s Bank built the building in 1890 and had offices on the first floor. The rest of the building was occupied by the Missouri Athletic Club (MAC), founded in 1903. The men’s club remodeled to house dining and meeting spaces, a gym and swimming pool, a Turkish bath, barber shop, bar, and an area of small sleeping rooms, all made of wood, for 97 members and guests on the fifth and sixth floors. Most of the victims of the fire were trapped there or died trying to escape. About 90 members, guests, and employees were in the building at the time of the fire, though the desk registry was destroyed so no one can be sure.
One Meridian Plaza Fire
Three Philadelphia firefighters lost their lives fighting the largest high-rise office building fire in modern American history at the Meridian Bank Building, also known as One Meridian Plaza. Twenty-four additional firefighters were injured. The fire extended from the 22nd up to the 30th floor, with an estimated $100 million in direct property damage. Twelve-alarms brought 51 engine companies and over 300 firefighters to the scene.
Construction on the 38-story Meridian Bank Building began in 1968 and was completed for occupancy in 1973. The building’s fire protection systems was upgraded around 1988. Manual pull fire alarms were replaced by automatic central station monitored alarms. The originally installed dry standpipe system was replaced with a wet system that was fed by Continue reading “On this Date in History: February 23, 1991” »
The purpose of fire inspections is to evaluate and minimize the risk of fires. In general, routine inspections are conducted on commercial, industrial, and apartment buildings to ensure that the appropriate fire safety requirements are being met. These inspections are vital for public safety. Fire inspectors usually inspect for some of the following: