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Mechanical, Electrical, and Plumbing Introduction Lee Harrelson, PE, LEED ® AP Principal, TM/R Engineering. Agenda. Building Systems Planning Room Sizes and Area %’s Mechanical Systems Equipment Identification and Application Considerations Outside Air Electrical Systems
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Mechanical, Electrical, and Plumbing IntroductionLee Harrelson, PE, LEED® APPrincipal, TM/R Engineering
Agenda • Building Systems Planning • Room Sizes and Area %’s • Mechanical Systems • Equipment Identification and Application Considerations • Outside Air • Electrical Systems • Equipment Identification and Application Considerations • Energy Code Considerations • Plumbing Systems • Equipment Identification and Application Considerations
Building Planning • Q: How much space for MEP systems? • A: Who knows? It depends on many factors: However, this website is a great starting point. http://www.repwars.com/PSP/mechroom.html
Mechanical Systems • Packaged Rooftop AHUs • Application Considerations • Exhaust fans more than 10 feet away from OA intake • Roof slopes coordinated with equipment • Clearance on one side of unit equal to unit width http://www.trane.com
Mechanical Systems • Modular Indoor AHUs • Application Considerations • Clearance on one side of unit equal to unit width • Space for duct connections (large turning radius) http://www.trane.com
Mechanical Systems • Fan Coil Unit • Application Considerations • Cannot place systems furniture partitions in front of unit • Minimal air-throw, cannot serve large space • Can be concealed in a perimeter millwork “bench” http://www.trane.com
Mechanical Systems • Air-Cooled Chiller • Application Considerations • Located Outdoors • Very Noisy • No harmful plume http://www.trane.com
Mechanical Systems • Water-Cooled Chiller • Application Considerations • Located Indoors, but extremely noisy • Needs 5 feet clearance on 3 sides and entire length of unit on end • Must be connected to a Cooling Tower (outside) http://www.trane.com
Mechanical Systems • Open Cooling Tower • Application Considerations • Located outdoors, noise and vibration • Emits a saturated air plume which can cause damage to nearby buildings • Screening must have high free area http://www.baltimoreaircoil.com
Mechanical Systems • Outside Air Requirements • Fresh Air is brought into the building to dilute the contaminants in the space. • Offices – 7 people/1000 ft2 and 20 CFM/person • Auditoriums – 150 people/1000 ft2 and 15 CFM/person • Classrooms – 50 people/1000 ft2 and 15 CFM/person • Libraries – 20 people/1000 ft2 and 15 CFM/person • Corridors and Storage – 0.10 CFM/ft • Why does this matter? • Large duct sizes, excessive loads that strain existing infrastructure requiring more mechanical space.
Mechanical Systems • Duct Shaft Sizing • How much space required for mechanical duct chases? • Rule of Thumb – Assume 1 CFM per square foot and assume 1000 feet per minute duct velocity • Example: Suppose an AHU serves a 20,000 ft2 floorplate. The AHU is located in the basement and serves the 2nd floor. • 20,000 ft2 needs roughly 20,000 CFM or 20,000 ft3/minute • Divide 20,000 ft3/minute by 1000 feet/minute to get duct cross sectional area. • 20,000/1000 = 20 ft2 required duct area • Remember…that’s just for the supply duct! We also have a return duct, outside air duct, exhaust ducts and we need space for piping.
Electrical Systems • Transformers • Application Considerations • Near electrical service entrance, inside or outside • Generate lots of heat • Service clearance depending on voltage, 3 to 5 feet typically
Electrical Systems • Switchgear • Application Considerations • Service clearance depending on voltage, typically 3 to 5 feet
Electrical Systems • Distribution Panel boards • Application Considerations • Service clearance depending on voltage, typically 3 feet
Electrical Systems • Bus duct Risers • Application Considerations • Should not offset. Bends are large, expensive, and very difficult to install • Space is required around the bus duct to install the disconnect switches
Electrical Systems • Electrical Room Stacking • Application Considerations • Prevents offsetting of vertical power distribution such as bus ducts or cable in conduit • Increases system efficiency by reducing cabling run distances
Electrical Systems • Energy Code and Lighting Power Allowances • Application Considerations • Most code reviewers are enforcing the International Energy Efficiency Code – 2003. • 1.1 watts/ft2 for offices • 1.4 watts/ft2 for classrooms and lecture halls • 1.9 watts/ft2 for workshops areas • 0.9 watts/ft2 for corridors • This often precludes reuse of existing inefficient lighting in renovation projects. T-5 fixtures are preferred.
Plumbing Systems • Plumbing Piping Note: Drains sloped at 1/4” to 1/8” per foot of run depending on size Hubless Sanitary Vent Piping Hubless Sanitary Drain Piping Storm Drain Piping Insulated Domestic Cold Water Piping
Plumbing Systems • Double Check Backflow Preventers • Application Considerations • Used to prevent contamination of city water supply • Installed at water service entrance to building • Typically require a floor drain • Must be accessible for inspection and repair
Plumbing Systems • Roof Drains • Application Considerations • If parapet wall is installed, a secondary drain path must be provided to discharge above grade. Use scuppers or internal secondary system which is very costly. • Must drain by gravity
Plumbing Systems • Toilet Room Stacking • Should stack to minimize drainage stack offsets. • Drainage stack offsets (a bend greater than 45o) must be separately vented, increasing cost and required space • Venting is required to prevent backpressure in the piping, which will prevent proper draining
Plumbing Systems • Toilet Room Stacking • Venting an offset
Plumbing Systems • Stormwater Harvesting http://www.constructionresources.com/images/products/services/rainwater_system.jpg
MEP Introduction • Questions?