Building SYSTEMS (part ONE of two)

BUILDING SYSTEMS(PART ONE OF TWO)

February 18, 2014

Presented by AIA-Pittsburgh’s Young Architects’ Forum (YAF)

and

Exam resources are available at AIA-PGH YAF ARE Reviewhttp://yafpghare.wordpress.com/

http://yafpghare.wordpress.com/


Agenda

5:30 Introduction / Division Overview 5:45 Graphic Vignette Review 6:00 Multiple Choice Content Review …

Electrical 6:45 Break (if desired) 7:00 Multiple Choice Content Review …

Lighting 7:45 Questions?

Division StatementEvaluate, select, and integrate mechanical,

electrical, and specialty systems in building design and construction.

Exam Structure 95 Multiple-Choice Questions (2 hours)

Break (15 minutes)

1 Graphic Vignette (1 hour) Mechanical and Electrical Plan

Test Day…

Introductory Tutorial 0:15 Multiple-Choice Questions 2:00 Scheduled (Mandatory) Break 0:15 Introductory Tutorial 0:15 Graphic Vignette 1:00 Exit Questionnaire 0:15 TOTAL APPOINTMENT TIME 4:00

Suggested Sequence

Construction Documents and Services Programming Planning and Practice Site Planning and Design Structural Systems Building Systems Building Design and Construction

Systems Schematic Design

Content Areas CODES & REGULATIONS (5-8% of scored items)

“…building codes, specialty codes, zoning, and other regulatory requirements…”

ENVIRONMENTAL ISSUES (10-15% of scored items) “…sustainable design principles…”

PLUMBING (10-15% of scored items) Principles Materials and Technology

HVAC (18-23% of scored items) Principles Materials and Technology

ELECTRICAL (10-15% of scored items) Principles Materials and Technology

LIGHTING (18-23% of scored items) Principles Materials and Technology

SPECIALTIES (14-19% of scored items) Principles Materials and Technology

By the numbers… 95 questions… 2 hour testing time……1 minute, 15 seconds per question By content areas…Codes/ Regulations….…………..……………..…4 - 8 questionsEnvironmental Issues..……………..……..…..10 - 15 questions Plumbing……………………………………….....10 - 15 questions HVAC…………………….…………………….……17 – 22 questions Electrical ……………………………………….....10 - 15 questions Lighting..……………….…………………….……17 – 22 questions Specialties………………………………………...13 – 18 questions

MECHANICAL & ELECTRICAL PLANDevelop a reflected ceiling plan that

integrates ceiling, lighting, mechanical, and structural systems and incorporates life safety considerations.

PROGRAMA reflected ceiling plan for an architect’s office is to be prepared. The space is in a multistory building and is enclosed by leasable office space on one side, a corridor on another, and two exterior walls. The client wants flexibility for furniture placement, efficient lighting levels, and a comfortable environment.

GRAPHIC VIGNETTE

The Work Screen

Mechanical and Electrical LayoutThe ProblemComplete the partially completed reflected ceiling plan on the work

screen by:(1) providing a grid for acoustical tile, (2) locating lighting fixtures to achieve specified light

intensity, and (3) developing a schematic HVAC plan complete with

fire dampers and air diffusers, ductwork, and return-air grilles to meet specified air distribution requirements.

It is recommended that the ceiling layout be completed before ducts are added. Your solution must be contained within the perimeter walls of the overall space.The completed plan should reflect effective coordination and integration of structural, mechanical, and electrical units within the ceiling grid and should provide for maximum flexibility for furniture layouts at the most economical cost.

Program RequirementsComply with the following requirements to develop the reflected ceiling

plan:Suspended Ceiling System1. Provide a 2 ft X 4 ft grid with lay-in acoustical tiles in all spaces.

2. All ceiling heights are 9 ft above the finished floor.3. Typical walls terminate 6 inches above the finished ceiling; bearing walls and fire-

rated walls extend to the bottom of the floor deck above.

Lighting System -- should be efficient and should minimize overlighting and underlighting.

1. For all spaces, use only recessed fluorescent fixtures to provide uniform light distribution with a light level of approximately 50 footcandles measured at desk level (3 ft above the finished floor).2. In addition to the fluorescent fixtures required above, provide recessed accent

light fixtures. Locate the accent light fixtures along the west wall of the Architect’s Office so

that the direct light level on the wall at a height of 5 ft above the floor is 80 footcandles.

Space the accent light fixtures so that the light level between the fixtures at 5 ft above the floor is 80 footcandles.

The accent light fixtures should not be considered in determining the uniform light distribution levels.

The recessed fluorescent fixtures should not be considered in determining the accent light levels.

Program Requirements, cont.HVAC SystemThe space is served by the supply and return risers within the shaft indicated on the

floor plan. The HVAC system should provide for uniform air distribution with an economical duct layout conforming to the following restrictions:

1. Provide a minimum of one supply diffuser and one return-air grille in each space. An acceptable air distribution pattern includes one supply diffuser and one return-air grille for every 144 ft of floor area (or portion thereof ) in each space.

2. Connect each supply diffuser to the rigid supply duct system with flexible duct. Do not exceed 10 ft for flexible duct lengths.

3. Return-air grilles are open to the ceiling space, which serves as a return-air plenum. Connect the plenum to the return riser with rigid duct.

4. Protect duct openings in fire-rated walls with fire dampers.

5. Flexible ducts fit through joist webs.6. Rigid ducts fit under beams, in spaces between joists, and in a zone that extends 2

ft on either side of beams and bearing walls in plan view. Rigid ducts do not fit through joists or between the bottom of joists and the ceiling.

Program Requirements, cont

Mechanical & Electrical LayoutSample PASSING Solution

Mechanical & Electrical Layout Sample FAILING Solution

General Tips…Clear your head. Remember – it’s not AutoCAD… … or design studio. Practice makes perfect… … but don’t over-practice!!Take your time. Follow all of the instructions!!Don’t second-guess yourself.

Everybody read this!If you have 2' between the long sides of 2x4s, you're doing it wrong.

If you're using circles for anything but accents, you're wasting your time.

GRAPHIC VIGNETTE

Frequently Asked Questions:Q. Does it matter which way the damper points?A. This appears to be a minor issue at most. The long leg of the symbol must be parallel to the

wall…either in the center of the wall or at the face of the wall.

Q. How do I center the grid precisely?B. You don’t. Just get it as close as you can. The snap setting will not permit exact centering.Q. What if I have ceiling tile slivers?C. Doesn't matter. This is a ME vignette, not a pretty ceiling tile vignette. Center the lights.

Q. What is the ideal distance from the wall for lights?D. That depends on the type of light and the lighting chart that goes with it.

Q. Can ducts be placed above lights?E. Yes. Duct sizes and the plenum depth are not specified. If it mattered, NCARB would have to say

so.

Q. I can’t get the lights to fit the room to provide the ideal requirement. Should I over or under light the room?F. Decide which based on the use of the room.

Q. What is the ideal distance between supply diffusers and return grilles?G. A minimum of 4’ is recommended, but the farther apart the better.

Q. Should supply diffusers be placed on the window side of the room?A. There is no evidence that this matters to NCARB.

GRAPHIC VIGNETTE

Frequently Asked Questions: (continued)Q. Can a flex duct supply more than one diffuser?A. No. This is clearly defined in the program.

Q. The program specifies 1 set per 144 s.f. or portion thereof. If a room has 145 s.f., should I place one or two sets of supply/return? Do I just round up or down?A. 2 sets should be provided as a strict interpretation of the requirement but…the 3.1 sample passing solution had a room at 145 s.f. with only one set. The program also said to be efficient. An additional set for 1 s.f. is not efficient. Catch 22. If you are over the required area, add the extra set to be safe.

Q. How many accent lights do I need?A. That depends on the lighting chart. Determine how far from the light you can get the required lighting level. Draw sketch circles that size. Place them along the appropriate wall so that their intersections occur at the face of the wall. Then place the accent lights at the center of each circle. The goal is to cover as much of the wall as possible. Note if you change the distance between the lights, you change the distance from the wall as well because the intersection point of the sketch circles will change.

GRAPHIC VIGNETTE

Common Mistakes:1. Inadequate separation between supply & return. Should be at least 4ft apart.2. Return grilles not supported on 3 sides by the grid. They’ll fall out. Do not assume the software is smart enough to place grid on the 4th side of a 2x2 light.3. Incorrect light spacing. Read the lighting charts carefully. The current NCARB passing solution (2009) shows incorrect light spacing in the Architect’s Office.4. Connect the flex duct to the center of diffusers, not the edge.5. Grid overlapping ceiling elements.6. Rigid duct crossing joists when not within 2’ of a beam or bearing wall.7. More than one rigid duct for each riser. Adding an extra damper wastes money.Accent Lights:

GRAPHIC VIGNETTE

Strategy (checklist):Read program carefully. Jot down pertinent notes.•Draw grid in first room.•Draw lighting fixture at ideal intervals. Do not worry about centering yet, just get the distances correct. For example, if your lights are to be 4’ apart just start 2’ off the wall and place the fixtures at 4’ intervals. Stop when you are 4’ or less from the wall. Lights shall be no closer than 1’ from the wall and no further than 4’ from wall. Ideally, lights should be 3’ from walls due to bounced light from fixture combining with direct light on work surface at perimeter of room to meet desired illumination levels. (Assuming a 2’ spread of light).•Use the “move group” tool and shift the grid and lights so that they are centered on the room. If the layout does not appear acceptable, move the grid off to the side and either rotate it and try again or if another fixture is available to use try placing them in the same manner as above.•Continue for all rooms. Verify that spaces with different fixtures have the correct fixtures, and if rooms are NOT to have the grid then a grid is not provided. A grid can still be used to layout these spaces if the module is a 2 or 4’ module but make sure you delete it afterwards. If the spacing is other than a multiple of 2’ then draw sketch circles and place them side by side filling the room. Then place the fixtures in the center of the circles.•Click on the grid in the first room and read the square footage on the screen below. Determine the number of diffusers and returns based upon the program requirements.•Spread diffusers out for optimum air flow. Do not place in front of door or against walls. In front of windows is a good location.•Place returns at least 4’ away from diffusers at opposite sides of room. Do not place return against wall.•Support registers/diffusers on 3 sides.•Repeat for all rooms.

GRAPHIC VIGNETTE

Strategy (checklist): continued•Place fire dampers at supply and return risers. Short leg points in the direction of airflow.•Draw short length of duct from center of return riser to outside edge of fire damper to plenum air space.•Determine where rigid duct can be run perpendicular to joists and draw rigid duct out of riser and, following the program rules, over to a point between two joists that is perpendicular to the center of a line drawn between the two outermost diffusers to be connected to this run of duct. If necessary, branch a second run of rigid duct to pick up another string of diffusers in the same manner.•Draw duct portion perpendicular to joists in allowable area maintaining half the allowable distance from the wall/beam/allowable zone. Ducts have a thickness and representative line indicates center of duct so if you draw your duct the specified distance the duct will actually be out of the allowable zone.•Draw rigid duct between joists to a point perpendicular to the furthest diffuser for that run of duct. Do not turn rigid duct back towards risers, use additional branch of duct parallel to first branch if necessary to pick up more diffusers.•Connect the diffuser to the rigid duct with flex duct no more than 10’, connected to the center of the diffuser. Flex duct can run perpendicular to joists and can run on top of lights.•Does this imply that rigid duct can not run over lights?•Repeat for all diffusers for that branch of duct.•Repeat with second branch of duct if necessary. Try to keep all diffusers from a room on the same main branch.•If rigid return duct is called for, provide in the manner described for the supply duct.•Verify all rooms are properly lit, adequately ventilated, and all ductwork is continuous.

GRAPHIC VIGNETTE

Suggested Resources “References Available During the Test” document Mechanical and Electrical Equipment for Buildings Heating, Cooling, Lighting (Lechner) Dustin Goffron’s “Helpful Links for the ARE 4.0”

http://www.dustingoffron.com/ARE/ Alkikat’s Study Guide Jenny’s Notes (AREndurance)

www.arendurance.files.wordpress.com YouTube’s “WikiEngineering” channel MEEB’s Student Companion Site

http://bcs.wiley.com/he-bcs/Books?action=contents&itemId=0471465917&bcsId=2879

CED Engineering.com’s “Design Options for HVAC Distribution Systems” http://

www.cedengineering.com/upload/Design%20Options%20for%20HVAC%20Distribution%20Systems.pdf

http://www.dustingoffron.com/ARE/

http://www.dustingoffron.com/ARE/

http://www.arendurance.files.wordpress.com/




http://www.cedengineering.com/upload/Design%20Options%20for%20HVAC%20Distribution%20Systems.pdf



Suggested Resources ARE Building Systems Study Guide and Practice Exam (The

Amber Book) By Michael Ermann Professor Norman Dorf’s ARE Solutions

Content AreasElectrical

Lighting


Study Resources:Building Systems

Study Guides NCARB Exam Guide

“References Available During the Test”



Study Guides Alkikat Building System Notes + Diagrams Jenny’s AREndurance Study Guide ArchiTangent’s ARE Prep: Building Systems

Study Resources:Building Systems


Study Resources:Building SystemsExam resources are available at AIA-PGH YAF ARE Reviewhttp://yafpghare.wordpress.com/

Jenny’s AREndurance Study Guide DISCLAIMER



Lighting

Basic Electrical PhysicsElectrical

VOLTAGE ( V ): measured in volts, the amount of force or potential in a circuit

CURRENT ( I ): measured in amps, it’s the amount of flow through a circuit

RESISTANCE ( R ): measured in ohms, the amount that slows down the current

Basic Electrical Physics – Water Analogy

Electrical

PotentialWaterHeight, pressure, or pressure difference ( feet or psi )

Flow ( gallons per minute )

Resistance to Flow ( inches per 100 ft. )

Current

Resistance

ElectricityVoltage V ( volts )

Current I ( amps )

Resistance R ( ohms )

Basic Electrical Physics – VOLTAGE ( V ) in volts

Electrical

“ Water Pressure “

Basic Electrical Physics – CURRENT ( I ) in amps

Electrical

“ Water Flow“

Basic Electrical Physics – RESISTANCE ( R ) in ohms

Electrical

“ Resistance to Flow“

Basic Electrical Physics – CIRCUITElectrical

RESISTANCE( light bulb )

VOLTAGE( battery )

CURRENT

CURRENT

Ohm’s LawElectrical

VOLTAGE ( V )

CURRENT ( I )

RESISTANCE ( R )

V = I x R

I = V / R

R = V / I

V and I are directly proportional to each other > the greater the voltage, the greater the current

I and R are inversely proportional to each other > the greater the resistance, the smaller the current

Ohm’s Law ExampleElectrical

Given a 120 volt outlet and a hair dryer with a resistance of 8 ohms, the current flow through the hair dryer when it is turned on is _____ amps.A. 15 ampsB. 6.7 ampsC. 1.5 ampsD. 0.67 amps

CURRENT ( I )

I = V / RI = 120 v / 8 ohmsI = 15 amps

ResistanceElectrical

SERIES Resistance: Resistors situated in one pathPARALLEL Resistance: Resistors situated in multiple paths


SERIES Resistance: Resistors situated in one path

In a Series … Effective Total Resistance = Sum of All ResistancesRs = R1 + R2 + R3


PARALLEL Resistance: Resistors situated in multiple paths

In Parallel … Effective Total Resistance = Inverse of Sum of Inverse Resistances

1/Rp = 1/R1 + 1/R2 + 1/R3 OR Rp = 1 1/R1 + 1/R2 + 1/R3


Resistors situated in Series AND Parallel

Transmission of ElectricityElectrical

Direct Current ( DC ) Current flows in ONE direction, with constant voltage Example: Batteries DC Power Equation: Power ( watts ) = Voltage x Current

P = V x I

Example: A 12 volt battery connected to a 4 ohm resistor … the current is ____ ? I = V / R = 12 v / 4 Ω = 3 amps P = V x I = 12 v x 3 amps = 36 watts


Alternating Current ( AC ) Electricity has nearly zero inertia and therefore the direction of flow can be reversed very rapidly by reversing the voltage.

Single-Phase Three-Phase


Single-Phase AC Power Equation P = V x I x PF ( PF = Power Factor in decimal form )

Three-Phase AC Power Equation P = V x I x PF x √ 3 ( PF = Power Factor in decimal form )Example: A three-phase motor draws a current of 7 amps at 240 volts and the power factor is 0.8… the power is ____ ?

P = V x I x PF x √ 3 = 240 v x 7 amps x 0.8 x 1.73 = 2,325 watts

EquipmentElectrical

Motor vs Generator

Motor > converts electrical energy into mechanical energyRunning a current through a wire loop creates a magnetic field. This is the basic principle behind electric motors and solenoids.

Generator > converts mechanical energy into electrical energy

Rotating a wire loop between two magnetic poles will generate a current. This is the basic principle behind generating electricity.

EquipmentElectrical

Motor Types

Four types in general use:1. DC motor – small scale applications, elevators

for smooth continuous acceleration2. Single phase AC motors – typically 3/4HP or

less such as exhaust fans, pumps, etc.3. 3-phase induction motors – larger motors,

constant rpm such as air handlers, power factors from 0.7 to 0.9

4. Universal motors – DC or AC, variable speed, such as hand drills, mixers, similar appliances

EquipmentElectrical

Transformer

Transformers > change the voltage of AC Circuit Consist of an iron core on which two separate coils of wire are wound, called the primary and a secondary “windings”

“Step-Up” Transformer … changes to a higher voltage“Step-Down” Transformer … changes to a lower voltage

Waste energy is HEAT, which must be dissipated.Transformer sizes are defined in volt-amps ( VA ), or kilovolt-amps ( KVA )

EquipmentElectrical

Transformer Voltages

Typical commercial system voltages:480Y/277V-3ph-4w and 208Y/120V-3ph-4w

Typical residential system voltage:120/240V1ph-3w

Older buildings sometimes had two services:120/240V-1ph-3w 240V-3ph-3w delta for motor loads

EquipmentElectrical

Transformer Voltages … Which One to Choose?

– What is available from the power company?– What is the building square footage?– Building use? (industrial, office, retail, warehouse, multi-tenant, high-

rise)– Standard distribution equipment sizes and how they affect architecture

(NEC workspace clearances, multiple doors to main electrical room, doors with panic hardware opening outward from the room)

– What makes sense for the major equipment?– Also … higher voltage = lower current = smaller wire

higher voltage = better tolerance for voltage drop higher voltage = more load per circuit = fewer circuits used

EquipmentElectrical

Panelboards

Types: Fuse box, Circuit breaker panelboard, Frankenstein panel (old)– Provides a central distribution point for branch circuit wiring– Each breaker serves a single circuit– Overcurrent protection is designed to protect the wiring to the

load– Power riser diagram includes all of the panelboards and their

interconnections (conduit and wire) all of the way to the service entrance

– NEC defines clearances required at panelboards( 36” front clearance, 30” clear width, 72” headroom, etc. )

Electrical DistributionElectrical

Riser Diagram Components

– Service entrance– Main service disconnect– Main switchboard– Feeders– Distribution boards– Feeders– Branch panelboards– Branch circuits

Electrical DistributionElectrical

Example QuestionElectrical

Answer: D

ComponentsElectrical

Conduit

– Rigid – steel, safest, same wall thickness as Schedule 40 PVC, connections are threaded, galvanized for exterior use.

– Intermediate Metallic Conduit (IMC) – steel, slightly thinner and less expensive than rigid.

– Electrical Metallic Tubing (EMT) – thinnest of the simple metal conduits, compression fittings, galvanized, called “thin wall”.

– Flexible Metallic Conduit – available with or without a waterproof (liquid tight) jacket, called “flex” or “Greenfield”, can be used everywhere except underground.

– Interlocked Armored Cable (BX) – factory assembled wires encased in an interlocking spiral metal armor, (cannot add wires to it), cannot be used underground or embedded in concrete.


Receptacles

– Also called an outlet. ( A plug is what you put into the outlet )

– All 120V outlets should be 3-prong where the third prong is the ground.

– In a large room, provide more than one circuit for the outlets.– Receptacle placement in commercial buildings:

– show windows– HVAC equipment outlets– No “code” for convenience outlets


Receptacles in Residential

– NEC 210.52 has very specific rules on the placement of receptacles in dwelling units and hotels.

– 12 feet on center on any wall space greater than 2 feet in width for the following rooms:

kitchen, family room, dining room, living room, parlor, library, den, sunroom, bedrooom, or similar

– At least one receptacle for hallways of 10 feet or more in length.


Receptacles in Residential

– One in each basement– One for laundry– One for garage– One for each bathroom basin– One at the front and back exterior of each dwelling unit– One at each porch/balcony/deck– Kitchen countertops and islands


Switching for Lighting

Switching can be done centrally via circuit breakers in a panel, or locally via wall switches.

Switch types:– One switch location: need (1) 2-way switch.– Two switch locations: need (2) 3-way switches, one at each

location.– More than two switch locations need (2) 3-way switches at

each “end” location and a 4-way switch at every “in between” location.



One switch location: need (1) 2-way switch



Two switch locations: need (2) 3-way switches, one at each location



More than two switch locations need (2) 3-way switches at each “end” location and a 4-way switch at every “in between” location


Switching for Lighting … Alternate Names

SPST = 2-way SPDT = 3-way DPDT = 4-way

GroundingElectrical

– Ground wire provides a low resistance path for current to the ground in the event of a short circuit

– Ground wires are usually bare or covered with green insulation

– All ground wires are ultimately connected to a grounding electrode, such as building steel, a metal water pipe, etc. per NEC Article 250

Emergency PowerElectrical

– Emergency power is required for emergency egress lighting and exit signs

– IBC Section 1006 covers Means of Egress lighting levels and power sources

– Hospitals have special emergency power requirements– Stand-by power may be required for elevators– Lighting backup power is often provided through emergency

battery ballasts that are continuously recharged while power is on, and operate one or more lamps when normal power is lost

– Emergency lighting may be provided through individual emergency lighting units that contain a rechargeable battery. These operate only when normal power is lost

Emergency Power GeneratorsElectrical

– Generator fuel supply should be enough for two hours of runtime under load

– Common fuel supplies are diesel, natural gas, and propane– Separate automatic transfer switches are provided for life

safety, stand-by, and optional equipment loads.

Electrical Power SourcesElectrical

– Natural Gas– Gas / Oil Generators– Coal Plants– Hydroelectric– Photovoltaic– Wind– Nuclear


Question: An office which is occupied for 10 hours per day has a typical load of 10,000 W. If the electrical rate is 6 cents per kilowatt-hour, what do they pay in electric per day?

Answer: 10 hours / day x 10,000 W = 100,000 W-hrs / day

= 100 kW-hrs / day 100 KW-hrs / day x $0.06 / kW-hr

= $6 / day


Question:Which conduit system is unacceptable for embedding in concrete?A. Rigid ConduitB. Flexible Metallic ConduitC. Intermediate Metal Conduit (IMC)D. Interlocked Armored Cable (BX)

Answer: D. Interlocked Armored Cable (BX)


Question:What is the minimum required clear distance from the face of an electrical panel to the nearest obstruction?A. 24 inchesB. 36 inchesC. 48 inchesD. 72 inches

Answer: B. 36 inches


Question:The flow of electricity is affected by all of the following EXCEPT?A. potentialB. currentC. powerD. resistance

Answer: C. power

I = V / R


Question:In an overhead power district, the power company may provide service …

I. undergroundII. overheadIII. underground if the owner provides the conduit between the building and the power poleIV. underground if the conduit is encased in concrete

A. II only B. I, II, III, and IV C. II and III D. III and IVAnswer:

C. II and III

Questions ? ?? ???Electrical

Short Break . .. … Then Lighting . .. …Electrical


Lighting

LightingBasic Concepts

What is Light?

• Light is defined as that part of the electromagnetic radiation spectrum that can be perceived by the human eye

– Blue light (450 to 475 nanometers)– Green and Yellow light (at 525nm and 575nm)– Red light (at 650nm)

• White light is the combination of all wavelengths


Definitions

• Transmitted: light that passes through a surface...all other is reflected or absorbed

• Transparent: material that allows for an image to pass through ( glass )

• Refraction: material that changes an image while allowing it to pass through ( lens )

• Translucent: material that allows light to pass through, but not an image (frosted glass )

• Reflective: material that bounces a light off


Definitions

• Specular Reflection: results from a smooth polished surface like a mirror. The angle of incidence equals the angle of reflection

• Diffuse Reflection: results from a uniformly rough surface. It appears uniformly and the image of the source cannot be seen


Definitions

• Candlepower (CP): the measurement for the intensity of a source, and approximately equal to the horizontal output from a single candle

• Lumen (I): SI unit of luminous flux, a measure of the total amount of visible light omitted by a source. One lumen of luminous flux uniformly cast on 1 square foot of area creates an illuminate of 1 foot candle

• Illumination (E): the amount of light arriving at a surface • Footcandle (FC): the calculated amount of illumination on a surface• Luminance: the measurement of how bright light leaving an

illuminated surface is...it depends on reflectivity or transmittance.• Illuminance: the density of luminous energy expressed as lumens per

unit area


Definitions

• Coefficient of Utilization (CU): ratio between lumens reaching the working plane in a specific space and the lumens. Typically provided by the luminaire manufacturer, it’s an indication of the effectiveness of a luminaire in delivering light in a given space

• Light Loss Factor (LLF): effect of temperature and voltage variations, dirt accumulation on luminaries and room surfaces, lamp output depreciation, maintenance conditions

• Efficacy: the amount of light produced vs. the power input (lumens/watt)


Definitions

• Color Rendering Index (CRI): a measure of the effectiveness of a source to make colors “right” to the viewer. The best possible rating is 100. 85 + is good.

• Color Temperature (K): a characteristic of visible light where its color reveals it temp.


Equations


Measuring Light

• Photometric readings are usually taken at the height of a "working plane" because this approximates the height to typical visual tasks

• Typical fc levels• Office: 30-50 fc• Corridor: 10 fc• Surgery Suite: 100-500 fc• Emergency egress: 1 fc at floor


Light vs Lamp vs Luminaire

• Lamp: a device for giving light (e.g. a light bulb)• Luminaire: a complete light fixture, including lamp(s)

LightingDaylighting

Controlling Daylight

• Overhangs, fins, and other architectural shading devices.• Sawtooth (not bubble) skylights allow glass to face north for

illumination, not south for solar heat gain. • Interior window shading devices, which allow solar gain

during cool months, and the blocking of solar radiation during the warmer seasons.

• Light shelves, which permit the daylight to reflect off the ceiling and penetrate farther into the interior without affecting views outside.

LightingArtificial Lighting

Types

• Incandescent• Tungsten Halogen• Fluorescent• High Intensity Discharge (HID)• LED (Light Emitting Diode)


Incandescent

• Tungsten alloy placed within a sealed bulb containing an inert gas• Filament glows by passing an electric current through it• Advantages:

• Inexpensive • Compact • Instant on • Dimmable • Typically “warmer color that sunlight or daylight, rich in yellows and reds and weak in green and blues

• Disadvantages: • Inefficient (produce heat) • Short lamp life (~ 700 – 1,000 hrs)


Incandescent


Tungsten Halogen

• A variation of incandescent bulbs (under higher pressure and temperature)

• Smaller than standard incandescent bulbs• Advantages:

• Longer life • Low lumen deprecation of the life of the bulb• More uniform light color • Whiter light than incandescent • Dimmable • Instant on

• Disadvantages: • Much hotter than incandescent bulbs


Tungsten Halogen


Fluorescent

• A glass tube holds a mixture of an inert gas and low pressure mercury vapor

• When lamp is energized, an arc of mercury is formed creating an ultraviolet light that strikes the phosphor coated bulb

• Bulb fluoresces and produce a visible light• Ballast: supplies the proper starting and operating voltages

to the lamp and limits the current • Produces noise and heat


Fluorescent

• Advantages: • High efficacy (About 80 lm/W) • Low initial cost• Long life (about 10,000 - 20,000 hours) • Dimmable• Variety of color temperatures (improving...no longer just “cool white”) • For fluorescent lamps, dimming down to 40% of output is

possible without substantially reducing luminous efficacy • Instant on with slight warm-up

• Disadvantages: • More expensive than incandescent bulbs


Fluorescent


High Intensity Discharge (HID)

• A lamp within a lamp that runs at a very high voltage • An electrical arc is struck across tungsten electrodes in a glass tube

filled with gas and metals• Metals produce the light once they are heated to a point of evaporation • Advantages:

• High efficacy (About 80 lm/W) • Great for High Spaces or Outdoor use

• Disadvantages: • Produce light that is not flattering to human skin, so not used for

commercial / retail / residential applications • Long Warm-up Time


High Intensity Discharge (HID)


LED (Light Emitting Diode)

• Solid State Lighting• Bulbs without a filament, plasma, or gas• Low in power consumption with a long life span• Advantages:

• No UV rays • Instant on • Standard dimming

• Disadvantages:• Cost ( this is improving … esp. when considering life costs)

LightingSystems

Indirect

• 90% - 100% of light output is directed to the ceiling & upper walls of a room

• Almost all of the light reaches the horizontal plane indirectly, it has to bounce off something else first (so the ceiling & walls are basically the light source)

• Suspend 12”-18” from the ceiling minimum • Allows for uniform lighting, lacks shadows, low brightness, and

is highly diffuse • Pretty inefficient system• Typical Uses: Good for Offices, lounges, waiting areas

LightingSystems

Semi-Indirect

• 60% - 90% of light is directed upward, similar to indirect, but more efficient

• 10% - 40% of light is directed downward • Direct and reflective glare is relatively low • Kind of a monotonous system

• Typical Uses: Good for Offices, lounges, waiting rooms, corridors

LightingSystems

Diffuse / Direct-Indirect

• Equal distribution of light up and downwards• Bright ceilings and upper walls • All surfaces are lit • Give light in all directions, and should be suspended 12”

minimum from the ceiling • Efficient system

• Typical Uses: Good for classrooms, standard office work spaces, merchandising areas

LightingSystems

Semi-Direct

• 60% - 90% of light is directed downward • 10% - 40% of light is directed upward• Shadowing should not be a problem• A pleasant environment • Inherently efficient

• Typical Uses: Offices, classrooms, shops, working areas

LightingSystems

Direct

• Essentially all light is directed downward • Ceiling illumination comes from floor and furnishing reflection • Requires a light, high reflectance, diffuse floor unless a dark ceiling is

desired• Efficiency depends on if the distraction is spread or concentrating • Gives little surface illumination, requiring the addition of perimeter

lighting • Downlights create sharp, theatrical atmosphere, not good for work spaces• Can be gloomy and cave-like• Typical Uses: General Lighting (spread) OR Highlights, local /

supplemental lighting, and privacy atmosphere lighting (concentrated)

LightingSystems

Lighting Control

• Any building over 5,000 square feet is required to have Lighting Controls

• Occupancy Sensors • Relay Panels• A properly designed lighting control system can reduce

energy usage up to 60% over a simple on/off system

LightingOther Considerations

• Artificial Lighting consumes a significant part of all electrical energy• 20 – 60% of energy used in residential / business is due to lighting

• Light Pollution• Light Trespass – unwanted light on private property• Can reduce light levels at perimeters, or use shielding devices to block

• Emergency Lighting:• IBC, National Electric Code, Life Safety Code all have provision for

emergency lighting• Required areas include:

Exit Stairs Corridors Assembly SpacesEducational Facilities Other high occupancy loads

• Minimum lighting level required is 1 foot-candle at the floor level • Illuminated exit signs are required

Example Question

Question:Which of the following terms means “brightness” ?

A. LuminanceB. IlluminationC. GlareD. Radiation

Answer: A. Luminance

Illumination is the amount of light arriving at a surface (not leaving it)Glare results from extreme contrasts in brightnessRadiation is a method of transfer of heat or other energy

Lighting

Example Question

Question:The intensity of a light source is measure in what units?

A. LumensB. CandlepowerC. FootcandlesD. Lamberts

Answer: B. Candlepower

The rate of flow of light is measured in LumensA footcandle is a unit of illumination equal to one lumen per square footA Lambert is a unit of luminance or brightness

Lighting

Questions ? ?? ???Lighting

General Tips…

Study comprehensively… Save practice tests until the end. Don’t get stuck. Answer every question!

QUESTIONS…?

THANKS!

Building SYSTEMS (part ONE of two)

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Transcript of Building SYSTEMS (part ONE of two)