* Ductwork (supply and return)

* Registers, diffusers, grills, dampers

* blower (fan)

automatically close, triggered by a fusible link (similar to sprinkler systems)

*Installed in the plane of the fire wall.

1. purpose of smoke dampers is _______

2. smoke dampers controlled by ________

• can be part of an engineering smoke control system which uses walls and floors as barriers to create zones of pressure difference
• controlled by a smoke or heat detector signal that is part of a fire alarm control system
• so these need electrical sub coordination

1. diffusers have ________

2.  what do fire rated diffusers do?

• Have built-in louvers or defletors that throw and dispense air (supply air)
• Fire-rated diffusers closes to isolate the space under fire conditions

Grilles are ______

example of grill is ____

• Sets of vertical and horizontal vanes that are typically fixed (return air, typically)
• A register is a grill with a built-in damper (supply air)

• Airflow is predominantly parallel to the axis of rotation of the blades
• Often directly connected to their motors, which avoids losses associated with a drive belt

1. Centrifugal Fan example?

2.  airflow is turned ______ to axis of rotation

3. mass of fan is ___ from the axle requires _________ but is generally _________.

• AKA Squirrel cage fan
• Airflow is turned parallel to the axis of rotation
• Mass of the fan is farther from the axle requires more starting torque, but are generally quieter

Types of air in buildings

supply air supplies are to from ____ to ______

return air supplies air to- ____ to _________

recirculated air  supplies air to______ to ______ to ______

exhaust air supplies air from _____ to ________

make up air supplies replaces ________

ventilation air supplies air from ______ to ______

mixed air is ______

• Supply air -- from AHU to a space
• Return air -- from a space to AHU
• Re-circulated air -- space to AHU to space
• Exhaust air -- from a space to outdoors
• Make-up air -- replaces exhaust air
• Ventilation (outdoor, fresh) air -- from outdoors to a space
• Mixed air -- combination of air types
• Economizers/heat exchangers

CAV stands for

flow is ______ from _______ to _______

many require _______ at terminal units containing ________

generally_____ energy eficient than VAV

Constant air volume

• Flow (cfm) is constant from AHU to space
• May required re-conditioning at terminal units containing reheat coils
• Generally less energy eficient that VAV (b/c CAV's cool air then heat it later)

VAV stands for ________

flow controlled by _____ at terminal units

reconditioning required?

generally _____ energy efficient than CAV

more/less common b/c of _________

variable air volume

• Variable flow controlled by dampers at terminal units (VAV boxes)
• No re-conditioning required (usually)
• Generally more energy efficient than CAV
• More common b/c of energy efficiency

Positive pressure building zone = 

where does air from building go?

blow

• Air from building exfiltrates to the outdoors

Negative pressure building zone = 

where does air go?

suck

• Air from outdoors infiltrates into the building

Heat Wheel is a type of ______

also known as _______ or ________

what does heat wheel do between exhaust air and makeup air?

fabric of wheel ________ between two air streams

do air streams mix?

• A type of ERV
• AKA rotary enthalpy
• AKA heat recovery wheel
• Transfers heat between exhaust air and make-up air
• Fabric of wheel exchanges heat between the two air streams
• Air streams do not mix!

Economizers are 

also known as _____ control airflow

Mechanical device adjusting the amount of outdoor air allowed into an HVAC system.

dampers control airflow

Hydronic (water) systems

what is delivered to terminal units?

air passes over ____ at terminal units

• conditioned water delivered to terminal units
• air passes over conditioned water in coils at terminal units

Advantages of all-air systems

1.

2.

3.

• mechanical equipment can be isolated
• no drain pipes, electrical wiring, and filters at the conditioned space
• seasonal changeover very simple and easy to automate
• good flexibility because heating and cooling can occur in different zones simultaneously 

Disadvantages of all-air systems

1

2

• additional duct clearance required, which can reduce usable floor space and increase building height
• air balancing is complicated and requires periodic care

• central air-handling units and ductwork are not required
• unused zones can be shut down from central control
• individual room control with little or no chance of cross-contamination of recirculated air from one space to another
• easier to retrofit to existing buildings

Disadvantages of all-water systems

(4)

• more maintenance required. often the maintenance is done in occupied areas
• units that have condensate and drip pans must be flushed and cleared
• filters are small, low in efficiency, and require frequent replacement
• ventilation is unsophisticated--usually accomplished by opening windows or by installing outside wall vents

Advantages of air-water systems

(2)

• rooms can be individually controlled at relatively low cost
• size of the central air-handling unit can be reduced

Disadvantages of air-water systems

(4)

• controls tend to be complex
• secondary air can cause induction coils to foul
• filtering can be done at the terminal unit; however this requires frequent in-room maintenance
• a low chilled-water temp is needed to accurately control humidity levels

Chilled Beams

use _____ in pipes and _____ to distribute ____ from _____ to space

requires seperate_____ called passibe beams

major concern of chilled beams?

• Emerging sustainable technology (in the US, already used more frequently in Europe and elsewhere)
• Uses chilled water in pipes and natural convection (hot air rises, cool air sinks - induction) to distribute "coldness" from water to the space
• requires separate ventilation system (passive beams), though "active beams" may combine ventilation and cooling in one unit
• Must be at a temp to prevent condensation - moisture is a major concern!

Floor space for M/E systems

typically range from ___ to ____ %

Use of roof space for M/E equipment when designed for building

must be accounted for by a _____ engineer

Total pressure

always _____ in the direction of flow

total pressure = _____ + _______

always decreases in the direction of flow

Total Pressure = Static Pressure + Velocity Pressure

Static pressure and Velocity pressure

are mutually convertible and __________ in direction of flow

What should the duct aspect ratio be? 

_____ : ________

round duct cost multiplier roughly

.34?

.22?

.66? 

.87?

square duct cost multiplier

ratio = 

1.0?

.87?

.48?

.67?

1.0

1:1 ratio

rectangular duct cost multiplier 

1.0?

.84?

1.4?

1.1?

1.1

2:1 ratio

higher aspect ratio cost multiplier

>___

What is a building code?

(2)

• 2010 Oregon Mechanical Specialty Code
• 2009 International Mechanical Code (IMC)

Purpose of mechanical drawings and specs

to _______ 

has 4 things

To convey design and layout info to a contractor

• heating/cooling equipment (capacities, controls, layout, switches, design temps)
• air flows and quantities (ventilation and exhaust air quantities, vent and fan locations, duct layout and sizing, duct material, diffuser and grill sizing)
• water heating and piping - size and layout
• construction details

Labor costs for subcontractor

hourly wage = ______

employer tax - __________

fringe benefits - ________

insurance - ________

small tools ____________

total  60 $/hr

• Hourly wage-----$23-25/hr
• Employer tax, etc.------$4/hr (approx. 15-16%)
• Fringe benefits------$20/hr (fixed amount)
• Insurance-------$10/hr (approx. 22%)
• Small tools-------$1/hr (approx. 4%)
• Total = $60 / hr

fees that are a % of the base hourly rate

(3)

Employer taxes

are a percentage of _______

Billing costs

hourly cost ______

overhead __ to ___ % roughly _____ $/hr

profit ___ to _____%  roughly _____ $/hr

total costs billed to general contractor - _____ $/hr

• Hourly cost-----$60 / hr
• Overhead----(10-12%)---$6.6 / hr
• Profit (5-7% of hourly + OH)---$4 / hr
• Total cost billed to GC = $70.6 / hr

Leed project costs

are typically __ to ____ % of the total building cost depending on level of certification

BIM

_____ onsite productivity

additional design/overhead ___ and ______

up to ____% reductions in cost and schedule have been reported

_____ typically takes the lead

• Mechanical contractor typically takes the lead
• Additional design/overhead time and costs 
• Improved productivity on-site
• Up to 25% reductions in cost and schedule have been reported

Mechanical Estimating

part of ____

(4 steps)

part of the "Acquisition Process"

1st step: document review (bid form, alternates, assemblies, labor feedback

2nd step: Quantity Take-Off (QTO, quantity survey)

3rd step: Pricing: Labor rates, material, equipment costs

4th step: Compiling - adjustements - overhead and profit ("fee")

• Water drained from buildings, treated, and released into the environment
• Community sewage treatment - preliminary, primary, secondary, and tertiary (final) treatment
• On-site sewage treatment - septic tanks, typically allowed only when building is +200 ft from sewer

• Copper
• Steel
• Cast Iron
• Thermoplastic

• Common for supply pipes
• Types K, L, M (K has the thickest walls)
• Soldered fittings
• Can be rigid (hard temper) or flexible (soft temper)
• Can corrode with acidic fluids (pH < 6.8)
• Good water flow (low friction)
• Easier workability than steel

• Joined with cement-solvent welding, insert couplings, clamps
• Can be cut with a saw
• PVC can deteriorate under UV light

thermoplastic pipe

• various uses - natural gas supply, water supply, Tyvek "house wrap", waterproofing liners, etc
• Increasingly popular material

Fittings

elbows?

Tees:

couplings

adapters

• Elbows: 45°, 90°, sanitary bend (gradual)
• Tees: branch off a straight run of pipe; reducing T, sanitary T, sanitary Y
• Couplingsa: join straight runs of pipe; union, reducer, increaser
• Adapters: for supply pipes where threaded pipe connects to non-threaded pipe

• A device that uses supply water and discharges wastewater
• Water closets (toilets), urinals, faucets, showers, dishwashers drinking fountains, hose taps, sinks, bathtubs, laundry washing machines, etc
• Typically the only part of a plumbing system visible to building users

Floor-set or wall-mounted

-- Need structural support ("carriers") in either case -- floor joists or wall studs

(requires a tank) flushing mechanism

Standard WC uses 1.6 gals/flush (GPF)

High efficiency WC uses 1.1 gal/flush (GPF)

Standard urinal uses 1.0 gal/flush

high efficiency = .125 gals/flush

• Use a less-dense-than-water sealant to trap odors
• No supply pipes required
• Require regular replacement of cartridge
• Popular for water conservation
• Some problems reported...

Standard uses 2.5 GPM

High efficiency uses down to 0.5 GPM

Standard uses 2.5 GPM

High efficiency uses 1.8 GPM

1. Building supply -- brings potable water from city to the building's meter via a service lateral (undergound pipe suppling building)
2. Water meter -- measures consumption
3. Building main -- (rigid pipe distribution) ; Large pipe that serves as the principle artery of the supply system ; Typically run in a basement, ceiling, crawlspace, or beneath the slab ; Carries water from the building supply to the furthest riser in the building
4. Riser -- (rigid-pipe distribution) ; Vertical supply pipe that extends at least one floor ; Runs in the wall, or within a pipe chase, to supply water to the fixture branches
5. Fixture branch -- (rigid pipe distribution) ; Runs from the riser to the fixture group, usually in the floor or wall ; Term used for anything other than a main or a riser
6. Fixture connection -- Runs from the fixture branch to the connection at the fixture ; Typically involve shutoff valves

• Traditional system
• Copper pipe (rigid), hot and cold pipe run parallel
• Branches supply zones and groups of fixtures
• Similar to dual-duct HVAC air distribution

• Pipes run from manifold to each individual fixture
• Plastic pipe (flexible), from 2 chambers in manifold
• More pipe required, but less labor and less cost
• Similar to electrical panel distribution

water pressure (30 to 80 psi) in supply main drives water through the system

Pumps required for buildings above 5 stories

water pumped to an elevated tank for storage then gravity-distribution

Approx. 10 stories per tank to control pressure

5 to 15 psi

(30 psi for garden hoses)

Water supply pressure

typpically supply water at ____ to ____ psi

max for plastic pipes = ____ psi

provided at 30 to 80 psi

max of approx 40 psi for plastic pipe

Water velocity (water supply issue)

 code allowable ranges for plastic pipe? (fps) ___ to ______

up to ___ fps for equipment in mechanical rooms

allowable range set by code

• Typically 5 to 10 fps (5 fps max. for plastic pipe)
• Up to 15 fps for equipment feed in mechanical rooms

drastic drop in liquid pressure creating small vapor bubbles, which implode when pressure is restored

• deteriorates pipes, valves, equipment; sounds like gravel in pipe

a type of cross-connection, in which water flows in the opposite direction than intended; can contaminate potable water supply

• Can be caused by back siphoning, esp. in irrigation systems
• Prevented by air gaps or backflow prevention devices

caused by large pressure that develops when fluid in a pipe suddenly stops, like when an appliance shuts off water supply

• Noisy; can damage pipes or burst fittings
• Air chambers, which absorb the hydraulic shock, can become waterlogged or blocked
• Water hammer arrestors are devices that absorb hydraulic shock

any pipe expands somewhat due to temp; more for plastic less for copper

• Expansion bends and loops minimize damage due to thermal expansion

• Drain, waste, vent (DWV) systems
• Wastewater flows by gravity
• Vents introduce air into the system to ensure proper water flow and to prevent suction which breaks trap seals

• U-shaped bend in a pipe that forms a water seal, preventing sewer gas from entering a building ("P-traps" most common)
• Useful for retrieving dropped items...

empty pipes allowing air at atmospheric pressure into a drainage system

• purpose: to maintain water seals in traps, keeping sewer gas out of buildings
• Stack vent - vertical vent pipe extended through roof as high as necessary
• Individual (one vent per fixture); common, wet, and circuit (one vent for multiple fixtures) vents
• All fixtures must have a trap, all traps must have a vent

• Very little flexibility in installation
• Need proper slope for drainage

when all fixtures have been installed; verifies settings, caulking, valves, etc.

AHJ (Authority Having Jurisdiction) must be satisfied

what type of copper pipe has the thickest walls?

type l?

Type m?

Type k?