Facilities management paper
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ZemkeCh6PPT.pptxWater and Wastewater Systems
Chapter 6
Part 1: Water supply
Where does water come from?
Sources:
Ocean (requires desalination)
Rivers
Aquifers
Lakes/reservoirs
Las Vegas Water Infrastructure
Getting water into your building
“City water” – potable water that is supplied by a utility company
The water is cleaned and sanitized
Sent to your building at pressure
Well water – you pump your own water from an underground source
You are responsible for the water’s safety and quality
Constant pressure systems
Water enters the building at or below ground level
For low-rise buildings, the supply pressure should be sufficient to push water up risers and out along branches
For taller buildings, supplemental pumps are required to push water up.
Since they need to provide continuous pressure, these systems are called “constant pressure” systems
Can provide challenges for high-rise buildings or buildings that have a high peak usage of water
Example: hotel guestrooms in the morning
This is likely a flow, not pressure issue
Water dynamics
1 gallon of water weights 8.345 lbs
.434 psi to raise water 1 foot,
conversely 1 psi = 2.31 ft
A 20 floor hotel, with 10’ floors, provides
60 psi of water in all guest rooms,
how much psi must be applied?
147 psi
Gravity-fed (downfeed) systems
Water is pumped to a tank on the roof or an intermediate floor
The tank provides water to the floors below
Gravity provides good water pressure to water-using fixtures (the greater the distance)
When the tank’s water level gets low, a float valve signals a valve to open and refill the tank
Unlike a constant pressure system, the pumps do not need to operate continuously
Water distribution systems
Part 2: Wastewater systems
These remove waste water, or “effluent” from the property
Two types of sewer systems: stormwater and sanitary
Stormwater systems (or, storm sewers)
These remove environmental water outdoors, such as:
Rain
Snowmelt
Landscaping irrigation runoff
The water returns to the natural environment untreated
Environmental Considerations
Everything that enters the storm water system in Las Vegas makes its way back to Lake Mead.
petroleum products, fertilizers, herbicides, insecticides, trash, etc.
Sanitary sewer systems (or soil lines)
These remove wastewater from the building
The water must be treated before returning to the natural environment
Three methods of removing water from the property:
“City sewer” – just like “city water”, the sewer system is provided and serviced by a water utility company
Septic systems – if you are not connected to a city sewer system, you will probably have a septic system
If you are not connected to a city sewer system and your land cannot support a septic system, you will have to operate your own waste treatment plant
Discharge to public sewer system
Sewage Treatment
Return to Source
Septic systems
Effluent from the building flows into a septic tank
Solids in the water settle to the bottom of the tank, forming a layer of “sludge”
The liquids flow out of the tank through perforated pipes into the “septic field” or “leach field”
The earth and its residents (insects, worms, etc.) clean the water as it seeps downward
The water finally recharges its original source, such as an aquifer that supplies a well
Residential septic system
Septic tank cleaning
Additional sanitary system components: Ejector pumps
If you have plumbing fixtures or appliances below grade (below ground level), the effluent will need to be pumped up to the sewer line
Ejector pumps are capable of moving liquid that contains some solid or semi-solid material
Most pumps can only handle liquids
Ejector pump fails =
Additional sanitary system components: P-traps and S-traps (a.k.a., u-bend)
All plumbing fixtures must have a trap installed in the drain line
The trap retains some water at all times to form a liquid seal that prevents sewer gases from traveling up through the fixture and into the building
Additional sanitary system components: Grease traps
For commercial buildings, all fixtures that handle water containing fats, oils, and grease (FOG) are required to send the water through a grease trap
The grease trap collects the FOG so that it does not clog the municipal sewer lines
Grease trap installation / replacement
Grease traps need to be cleaned periodically
Improper/infrequent grease trap cleaning
Water Quality
What’s in your water?
Perfectly potable water may have quality issues in terms of:
Color
Odor
Taste
Clarity (turbidity)
Mineral content
Hardness (high alkalinity)
Scale – your building’s enemy
“Scale” (a.k.a., limescale) is a build-up of minerals that have precipitated out of the water; a symptom of “hard” water
The white, crusty scale forms a coating on the inside or outside of pipes
Forms a layer of undesirable insulation
Can eventually prevent water flow by clogging the pipe
Will provide a harborage for microbes
Scale
Scale build-up will lead to:
Increased energy costs, since your equipment has to work harder to do its job
Reduced equipment life
Can lead to dangerous water quality, such as Legionella
Effects of “hard water” damage
Hot topic: Vitamin C-infused showerheads
Hot water – how hot is too hot?
Domestic hot water (DHW): the temperature of water coming out of the tap should never exceed 115oF (46.1oC) to reduce the chance of scalding someone
Test this with a thermometer, not with your hand
Use faucets and showerheads with anti-scald protection
(mixing / tempering valves)
For process water, such as laundry or dishwashing, high temperatures are required
Provide employees with proper protective equipment to prevent scalding
Heating hot water (HHW)
HHW is used in some buildings to provide heating
(HHW) is not potable; it is never intended for human contact or consumption
Water is chemically treated to maintain water quality, HHW systems recirculate the water
How water is heated
Direct water heating system
The water comes into direct contact with the heating element
Indirect water heating system
The water comes into contact with pipes containing very hot water or steam, which is made in a separate heating system
Water heating equipment
Boilers – large tanks that heat and store water
Fire-tube: a tank of water with pipes running through it; flames shoot through the pipes to heat the tank of water
Water-tube: a tank of fire has pipes running through it; water flows through the tubes to pick up heat from the fire
Instantaneous water heaters
Also called “tankless” water heaters
These are direct heaters and use either an electric element or are gas-fired to heat water as it enters the unit
The water heats instantly; no storage tank is required
Advantages over traditional boilers and storage tanks:
No energy is used to keep stored water hot (although a lot of energy is used to heat the water instantly). Overall, significant energy savings
No storage tank means that the risk of Legionella is reduced
These units take up a lot less space than traditional boilers and tanks. They also weigh a lot less.
Legionella (Legionnaires Disease)
Legionella is a type of bacterium, a serious health concern when it grows and spreads in human-made building water systems. Can be fatal!
First identified in 1976 after an American Legion convention in Philadelphia, PA, caused by a bacterium identified as legionella pneumophila.
The bacterium thrives in warm stagnant water: plumbing systems, hot water tanks, cooling towers, and hot tubs are ideal.
Cases & liability
2006, OH, an outpatient died after drinking water from a contaminated faucet, $1.2 million settlement
2013, PA, four people contracted the disease from a building decorative fountain, $1.1million
2017, Las Vegas, 7 reported cases at the Rio Hotel
2017, Disneyland, 9 related cases
Property owners, managers, equipment manufacturers, maintenance companies among others, could face liability in the case of an outbreak
Water for recreation
If your property has a swimming pool, spa, water park, or wave pool, you must ensure that it is safe and sanitary
Swimming pools: need to manage
pH – not too high, not too low
Sanitizing systems
Chlorine or bromine systems
Ozone systems
Saline systems
Sanitizing chemicals break down faster with:
Temperature increases
Sunlight
Heavy usage
Weird but true…
If your pool area smells strongly of chlorine, you may need to add more chlorine
A strong chlorine odor indicate that the chlorine is working really hard to fight unsanitary conditions, releasing chloramines (which is what you smell)
This indicates that the chlorine is breaking down
Therefore, the chemical levels should be tested and adjusted to ensure safe operation
Spas and hot tubs
Since these amenities operate at higher temperatures than pools, we need to be even more vigilant
Typical temperatures range from 102–105oF (38–40.5oC)
Good temperature to support microbial growth
Viruses, bacteria, mold other fungi: infect skin or be inhaled through water vapor
Spas are especially dangerous for people with certain medical conditions, pregnant women, and small children
Water Management
Water management includes:
Preventing water stagnation, bacteria growth, scale and corrosion
Conservation
Good water conservation is less consumption, without affecting guest comfort or satisfaction.
Low-flow fixtures: faucets, toilets, showerheads
1.1 gal/flush vs. 3.5 gal, 1.5 gal/min vs 5 gal
Guest participation: linen & towel reuse program
Kitchen operations: thaw food in refrigerator vs. water, EnergyStar rated equip., pedal-activated faucets
Laundry: outsource service, high-efficiency equip., ozone laundry equipment.
Eliminate water-cooled equipment: walk-ins, ice machines
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