Determining Special Systems Flashcards
Evaluating and selecting the best lighting for a building depends on 8 factors:
- Required light levels for a specific task
- Age of users
- Glare
- Contrast
- Light uniformity
- Color
- Available light sources
- Efficacy
Required light levels for a specific task are determined by 4 factors:
- Nature of the task
- Age of the person performing the task
- Surface reflectance
- Speed and accuracy needed for completing the task
What is VCP (Visual Comfort Probability)?
VCP (Visual comfort probability) = metric used in evaluating the problem of direct glare, defined as the percentage of normal observers who may be expected to experience visual comfort in a particular environment with a particular lighting situation
What is the glare zone for direct glare?
Glare zone for reflected glare?
direct glare = above 45 deg angle from the light source
indirect glare = below 45 deg angle from the light source
What is a veiling reflection? How can it be solved?
Veiling reflection = when reflected glare interferes with the viewing task
Can solve by moving lighting source or task or providing general background illumination/specific task lighting
What are 4 primary types of artificial light sources?
- Incandescent Lamps
- Fluorescent Lamps
- High-intensity discharge (HID) lamps
- Light-emitted diodes (LED)
What is an incandescent lamp?
What are 4 pros? 3 cons?
Typical designation?
A tungsten filament is placed within a sealed glass bulb containing an inert gas. When electricity passes through the lamp, the filament glows and produces light.
Pros:
- Inexpensive
- Easy to install
- Compact
- Warm color rendition
Cons:
- Low efficacy
- High heat output
- Short lamp life
Nomenclature: ex A-21 where letter = shape and number = diameter at widest point in ⅛”
What is a Tungsten halogen lamp?
A type of incandescent lamp that has whiter light, longer lamp life, and higher efficacy, but operates at higher temperatures so needs to be enclosed in a second layer
What is a reflector lamp (R lamps) and parabolic aluminized reflector lamps (PAR lamps)
Types of incandescent lamps that contain a reflective coating built into the lamp which increases efficiency and allows more precise beam control. Suitable for outdoor use.
What is an elliptical reflector lamp? (ER lamps)
an incandescent lamp that is an improved version of R lamps by providing a more efficient throw of light from a fixture by focusing the light beam slightly in front of the lamp before it spreads out. Used for downlights with deep baffles or small openings
What are low-voltage miniature reflector lamps (MR lamps)?
a small tungsten halogen (incandescent) lamps that are available in a variety of voltages and beam spreads.
Consistently high output and lamp life and color temperatures that are whiter than standard incandescent.
What is a fluorescent lamp?
What are 4 pros?
contain a mixture of an inert gas and low-pressure mercury vapor. When energized, a mercury arc is formed that creates ultraviolet light that causes the bulb to produce visible light.
- high efficacy (about 80lm/W)
- relative low initial cost
- long life
- range in color temperature from cool to warm
What is the typical use for incandescent bulbs? Fluorescent bulbs?
Incandescent bulbs are generally smaller (except for CFL), and so are better suited for downlights. Larger fluorescent lamps are better suited for general illuminatio.
What are 3 types of fluorescent lamps?
- preheat lamps = need time to warm up
- rapid-start lamps = start within 2 seconds
- instant-start lamps = carry constant charge for instant start
What is the ballast?
part of the light bulb that supplies and regulates proper voltage. Part of every gaseous discharge lamp.
What are 4 types of ballasts?
- magnetic = obsolete
- electronic = use less power, operate without noise/flicker, generate less heat, and allow dimming
- multilevel = used to change lighting levels evenly to conserve energy
- energy saving = reduces total lamp/ballast wattage by using a lower current, efficient ballast design, and disconnecting filaments after the lamps starts
What are High-intensity discharge (HID) lamps?
produce ultraviolet light and visible light. Need extra casing to protect from ultraviolet light. HID lamps need time to restart after shutting down to avoid failure.
What are 3 ways to rate efficiency of ballasts?
- ballast factor (BF) = ratio of the lamp’s light output when operated on a tested ballast to the lamp’s light output when operated by a standard refence “perfect) ballast. Helps determine which ballast is best for a particular lamp to reduce energy usage.
- ballast efficacy factor (BEF) = the ratio of BFx100 to the power in watts. Helps compare the efficacy of different ballasts with the same kind and number of lamps.
- power factor = measures how effectively the ballast converts supplied power into usable power (watts) for the lamps. a power factor of 0.90 or greater is considered high.
How are ballasts rated for noise?
A-F, where A is suitable for quiet environments and F is suitable for noisy environments.
What are High-intensity discharge (HID) lamps?
Where are they most often used?
produce ultraviolet light and visible light. Need extra casing to protect from ultraviolet light. HID lamps need time to restart after shutting down to avoid failure.
typically used when high levels of light are needed over large areas, such as gymnasiums, warehouses, roadways, parking lots, football stadiums, etc.
What are 4 types of HID lamps?
- mercury vapor
- metal halide
- ceramic metal halide (CMH)
- high-pressure sodium
What is a mercury vapor lamp?
How does it work?
Efficiency?
How long does it take to restart after being shut off?
A type of HID lamp in which electric arc passed through mercury vapor.
Moderately high efficiency.
3 min to 10 min to relight
What is a metal halide lamp?
How does it work?
Efficiency?
How long does it take to restart after being shut off?
A type of HID lamp in which electric arc passed through mercury vapor and a combination of metal halides.
Increases efficiency and color rendition, but shortens life.
10 min to 20 min to relight
What is a ceramic metal halide (CMH) lamp?
How does it work?
Efficiency?
How long does it take to restart after being shut off?
A type of HID lamp in which ceramic allows it to operate at higher temperatures and improves color rendition and light control. But higher cost and needs a ballast.
10 min to 20 min to relight
What is a high-pressure sodium (HPS) lamp?
How does it work?
Efficiency?
How long does it take to restart after being shut off?
A type of HID lamp in which electric arc passed through hot sodium vapor.
Extremely efficient and long life, needs to be made with color correction to offset its natural yellow light.
1 min to relight
What are 3 types of outer bulbs a HID lamp may use to protect people from ultraviolet light?
- clear bulb = optical control
- phosphor-coated bulbs = better color rendition
- diffuse bulbs = recessed downlight fixtures
What is an alternate to a high-pressure sodium (HPS) lamp?
low-pressure sodium (LPS) lamp = even higher efficacies, but even yellower light. Good for street lamps.
What are 5 advantages of LEDs?
2 disadvantages?
- long life
- brightness
- lack of heat production
- low power consumption
- variety in color or white light
- low efficacy (lumens per watt)
- high cost
What is efficacy in lighting?
ratio of lumens per watt = measures the energy efficiency of a light source.
What are neon lamp?
glass tubes filled with gas that can be formed into an unlimited number of shapes. Variety of colors can be produced by varying the gas. Often used for signs and specialty accent lighting.
What are cold-cathode lamps?
Similar to neon lamps in that they can be produced in long runs of thin tubing and bent to shape.
Higher efficacy and slightly larger.
What are fiber optic luminaires?
carries light from a remote light source to another area. Bundled optical fibers deliver light to the ends of the fibers.
What is a direct lighting system?
90-100% light directed down
What is a semi-direct lighting system?
60-90% light down, 10-40% up
What is a direct-indirect lighting system?
50% up, 50% down
What is a diffuse lighting system?
40-60% up, 40-60% down
What is a semi-indirect lighting system?
10-40% down, 60-90% up
What is an indirect lighting system?
90-100% up
What is a task-ambient lighting system?
When it is inefficient to light an entire space, provide a general background level of illumination and then separate light fixtures with individual controls at task/work stations.
What is the spectral energy distribution (SED) of a lamp?
The measure of energy output at different wavelengths/colors.
What is color temperature?
the temperature in kelvins to which a black body radiator would have to be heated to produce light of the same dominant color.
lower color temperature = warm colors
high color temperatures = cool colors
What is CRI index? What is considered an excellent CRI?
Color rendering Index = a measure of how closely the perceived colors of an object illuminated with a test light source match the colors of the object when it is illuminated with daylight of the same color temperature.
A CRI of 85 is excellent
What is IES TM-30-18?
new method for evaluating color rendition. helps find the preferred light source for a given application based on efficacy and color rendering.
What are the 3 basic qualities of sound?
- velocity
- frequency
- power
Which factors impact the velocity of sound?
depends on the medium in which the sound is traveling and the temperature of the medium.
What is the frequency of sound?
A high-pitched sound has _____ frequency.
A low-pitched sound has _____ frequency.
What is the range of sound frequencies that a healthy young person can hear?
the number of cycles completed per second, measured in hertz (Hz) where 1 Hz = 1 cycle/second.
higher
lower
20 - 20,000 Hz
What is the power of sound?
the amount of acoustic energy as measured in watts. This is what people perceive as “loudness”.
What is the threshold of hearing in dB?
0 dB
What is the threshold of pain in db?
130 dB
How will someone perceive a 1 dB change in sound?
almost imperceptible
How will someone perceive a 3 dB change in sound?
just perceptible
How will someone perceive a 5 dB change in sound?
clearly noticeable
How will someone perceive a 10 dB change in sound?
twice as loud/quiet
How will someone perceive an 18 dB change in sound?
very much louder/quiert
How will someone perceive a 20 dB change in sound?
four times as loud/quiet
What are the 2 basic problems with noise in design?
- Reducing sound transmission from one space to another
2. Reducing noise within a space
What is the difference between transmission loss and noise reduction?
Transmission loss = takes into account only the loss through the partition
Noise reduction = is dependent on not only transmission loss, but also on the area of the partition and the absorption of the surfaces in the quiet room.
What is the Sound Transmission Class (STC) rating?
a number used to rate the transmission loss of construction (walls & floors). The higher the STC rating, the better the barrier is in stopping sound.
What is the effect on hearing of an STC of 25?
normal speech can be heard through the barrier
What is the effect on hearing of an STC of 30?
loud speech can be heard/understood through the barrier
What is the effect on hearing of an STC of 35?
loud speech can be heard not understood
What is the effect on hearing of an STC of 42-45?
loud speech can be faintly heard
What is the effect on hearing of an STC of 46-50?
loud speech not audible. Loud sounds can be faintly heard.
What is Noise Criteria (NC)?
used to specify maximum amount of continuous background noise in a space. Quieter spaces (bedrooms, etc) need lower NC than do louder spaces (kitchens, etc)
What is the noise criteria of bedrooms, apartments, hospitals?
20-30 dB
What is the noise criteria of private offices or small conference rooms?
30-35 dB
What is the noise criteria of concert halls, opera house recording studios?
15-20 dB
What is the noise criteria of large offices, retail stores, restaurants?
35-40 dB
What is the noise criteria of lobbies, drafting rooms, laboratory work spaces?
40-45 dB
What is the noise criteria of kitchens, computer rooms, and light maintenance shops?
45-55 dB
What is the coefficient of absorption? What is the coefficient of absorption below which an object is considered reflective, and above which an object is considered absorptive?
Defines the absorption of a material.
Ratio of the sound intensity absorbed by the material to the total intensity reaching the material.
0.2
What are two metrics for absorption coefficients?
- NRC (noise reduction coefficient)
2. SAA (sound absorption average)
What is the difference between NRC and SAA?
They are similar and provide single numberical ratings, but SAA has superseded NRC.
NRC (Noise reduction Coefficient) = measures a material’s absorption coefficient at 4 frequencies: 250, 500, 1000, 2000 Hz
SAA (Sound Absorption Average) = average of the absorption coefficients for the 12 one-third octave bands from 200-2500Hz
What is reverberation? Why is it important?
Reverberation time?
Reverberation = the prolongation of sound as it repeatedly bounces off hard surfaces. It affects the intelligibly of speech and quality of music.
Reverberation time = the time it takes the sound level to decrease 60 dB after the source has stopped producing the sound
How is reverberation time in seconds calculated?
What happens if you increase the volume of the room? The sound absorption of the room?
T = 0.05 (V/A) V = room volume A = total sound absorption for a room
this formula is provided in the test resources
Increasing volume –> larger reverberation time. Better for larger spaces
Increasing sound absorption –> smaller reverberation time. Better for smaller spaces.
How do you calculate the sound absorption of a space?
a = SAC x S
where
a = Absorption of a material used in space (sabins)
SAC = Sound Absorption Coefficient of the material
S = Exposed surface area of the material (ft2)
this formula is provided in the test resources
What are 3 ways to control sound?
- Reducing the level of loudness of the sound source
- Modifying the absorption of the space
- White sound / random noise / acoustic perfume = Introducing non intrusive background sound to mask unwanted sound
Control of a sound through a barrier is dependent on which 2 factors?
Barrier’s mass
Barrier’s stiffness (lesser extent)
What are 5 ways to adjust a barrier’s mass to control sound?
- Add resilient channel or another layer of GWB
- Seal/caulk wall/floor edges and trim and penetrations
- Stagger outlets
- Doors:
- seal perimeter with weather stripping
- Threshold or automatic door bottom (drops a seal as the door closes)
- heavy door slab (solid-core best) - Glass: laminated glass provides more mass
5 factors that must all be achieved for designing speech privacy in an open area:
- Highly absorptive ceiling
- Space dividers to reduce sound transmission
- Arrange/design surfaces (floor, furniture, windows, light fixtures) to minimize sound reflections
- Distance activities property to take advantage of normal attenuation of sound with distance
- Provide a properly design
What is Impact Noise? How is it quantified?
sound of something hitting the barrier (walking, etc)
IIC (Impact Insulation Class) = a single number rating of a floor/ceiling’s impact sound performance
What are 4 ways to increase the IIC rating of a floor assembly?
- add carpet
- providing a resiliently suspended ceiling below
- floating a finished floor on resilient pads over a structural floor
- providing sound-absorbing material (insulation) in the air space between floor and finished ceiling below
What are Room Geometry and Planning Concepts to help with acoustic performance:
- Plan similar areas next to each other
- Use buffer spaces like closets/hallways to separate noise-producing spaces
- Stagger doorways in halls
- Locate furniture/other noise-producing objects away from a wall separating spaces
- Minimize area of common wall between two rooms where sound transmission reduction is desired
- Avoid shapes that reflect or focus sound (like barrel vaults of circular rooms)
What are 3 ways to acoustically rate ceilings:
- NRC values can be applied to ceilings
- SRA (Speech range absorption) = similar to NRC in that is measures absorbency of a material, but rated for speech frequencies
- CAC (Ceiling Attenuation Class) = measures transmission loss through ceiling tiles between two closed rooms where there is no wall or other barrier above the suspended ceiling. Units = dB, similar to STC.
What are 2 methods to measure speech privacy in open offices?
Articulation class (AC) = measures how effective a ceiling is in absorbing sound reaching it from over lower partitions
Articulation index (AI) = better method which measures the performance of all the elements of a configuration working together where 0 is complete privacy and 1 is no privacy
What are the 7 elements that Articulation Index (AI) measures?
What AI do you need to keep under to have an acceptable level of privacy ?
- Ceiling absorption
- Space dividers
- Furniture
- Light fixtures
- Partition
- Background masking system
- HVAC system sound
AI > 30 is unacceptable level of privacy
How to calculate noise reduction in a space?
NR = 10log(A2/A1)
A2 = total room absorption in sabins after increase A1 = total room absorption in sabins before the increase
What are 5 rules of thumb for noise reduction in a space?
- Avoid all hard, reflective surfaces on walls, floors, ceilings
- Average absorption coefficient of the room should be about 0.2
- To make any difference in noise reduction, change a materials absorption by x3, which will reduce the dB by 5.
- Ceiling treatment is more effective in large rooms, while wall treatment is more effective in small rooms
- Amount of absorption in a porous material (insulation, etc) depends on the material’s:
- Thickness
- Density
- Porosity
- Fiber orientation
What are 2 main types of elevators?
- Hydraulic
2. Electric (or traction)
What is a hydraulic elevator?
Hydraulic = lifted by a ram that must sink into the ground the full height of the elevator, so better for low rise buildings under 6 stories
Travel slowly, so better for freight or low-occupancy passenger when speed is not an issue
What is a electric (traction) elevator?
Electric (or traction) = most common elevator type for passenger service. A motor drives the sheave, over which ropes are suspended and move the elevator
What are two types of electric (traction) elevators?
- Gearless traction = high speed, dependable, easy to maintain. Use DC.
- Geared traction = slower speed but many options to adjust speed to meet building needs. DC or AC.
What is roping in an elevator? What are 2 types of roping?
the arrangement of cables supporting the elevator.
- single-wrap = rope passes over sheave only once and is then connected to the counterweight
- double-wrap = rope is wound over sheave twice for additional traction. Used in high-speed elevators. Results in shorter rope life.
What are 2 ways that the rope is connected to the counterweight in an electric (traction) elevator?
1: 1 = when rope is directly attached to counter weight and travels just as far as the car
2: 1 = when rope wraps around the sheave and travels twice the length of the elevator = requires less weight to lift the elevator = good for higher speed and smaller motors p to 700ft/min
What is elevator operation?
the way the electrical systems for an elevator or group of elevators answers calls for service
What is the best type of elevator operation for small buildings with little traffic and exclusive use?
Single automatic = simplest. Single button on each floor and in the car. Once someone is inside they have full control until they reach their destination. Best for small buildings with little traffic and exclusive use.
What is the best type of elevator operation system for moderate service requirements?
Selective collective operation = most common. The elevator remembers and answer all calls in one direction, and then in the reverse direction. Best for light to moderate service requirements
What is the best type of elevator operation system large buildings?
Group automatic operation = control of all elevators with programmable microprocessors to respond to calls as efficiently as possible. Good for light to moderate service requirements in large buildings.
What is the best type of elevator control system to reduce total travel time and results in fewer stops for each car?
Destination floor system: computer AI sorts requests for service by floor for efficiency. Riders input floor before they get on, instead of in the elevator.
What are elevator controls?
Controls = method of coordinating and operating all aspects of elevator service (travel speed, door opening delay, acceleration/deacceleration)
What is elevator drive control?
What are 3 types of drive control?
Drive control = controls the speed of motor that drives the traction machine
- Unit multivoltage (UMV) or Ward-Leonard = noisy, requires three machines, subject to high thermal loss and low efficiency. Not common anymore
- Silicon-controlled rectifier (SCR) or thyristor system = good drive and leveling control, but low power factor and high thermal loss.
- Variable-voltage variable-frequency (VVVF) = accurate and efficient speed control. Energy efficient. Good for all speeds and distances. Maintenance is minimized.
Elevator design involves selecting which 3 factors?
- Capacity
- Speed
- Number of elevators to adequately serve the building’s population
3 methods to avoid congestion of elevator use in tall buildings:
- Separate banks to serve separate zones (ie: bank 1 serves floors 2-10, bank 2 services floors 11-20)
- Sky lobby (intermediate lobby in tall buildings)
- Stacked or double-deck cabs: service separated by even/odd floor destination
What are recommended elevator capacities (in lbm) for small buildings?
ranges from 2000, 2500, 3000, 3500
What are recommended elevator capacities (in lbm) for medium buildings?
ranges from 2500, 3000, 3500
What are recommended elevator capacities (in lbm) for large buildings?
ranges from 2500, 3000, 3500, 4000
What are recommended elevator capacities (in lbm) for service elevators?
ranges from 4000-8000
What is the max passenger capacity for each elevator capacity (lbm)? 2000 2500 3000 3500 4000
2000 = 12 2500 = 17 3000 = 20 3500 = 23 4000 = 28
What 2 factors does elevator speed depend on?
What are common speeds ranges?
number of floors
general size of the building
100-300 ft/min (small buildings with <10 stories)
200-500 ft/min (small buildings with ~10-12 stories)
300-500 ft/min (medium buildings with <10 stories)
500-1400 ft/min (medium buildings with 10-60 stories)
400-1800 ft/min (large buildings)
How do you calculate how many elevators a building will need?
Car capacity and speed will determine the total number of people accommodated in a 5 min peak period and dividing by the handling capacity of one car.
How many elevator cars maximum may be enclosed in a single hoistway?
4 cars
What is a machine room-less elevator (MRL)?
Machine room-less elevator (MRL) = motor and control are located in the hoistway, eliminating the need for a machine room
What are freight elevators? What are the 5 classes?
Slower speeds than with passenger elevators
5 groups of freight elevators:
- Class A = general freight
- Class B = motor vehicle loading
- Class C1 = industrial truck loading, including the truck
- Class C2 = industrial truck loading, NOT including the truck
- Class C3 = industrial truck loading, concentrated loading and no truck
What is the standard speed of escalators?
Width?
Angle?
speed = 100 ft/min widths = 32", 40", and 48" angle = 30 deg
What are 4 typ arrangements for escalators?
- crisscross spiral (requires 2 total escalators)
- crisscross walkaround (requires 2 total escalators)
- parallel spiral (requires 4 total escalators)
- parallel walkaround (requires 2 total escalators)
What are min egress stair widths?
Min 36” for occ load < 50
Min 44” for occ load >50
Min 48” if serving an area of evacuation assistance
What are min key dimensions for winding stairs?
Circular stairs?
Spiral stairs?
Min 11” at 12” from interior. 6” min at narrowest point
Min 11” at 12” from interior. Min 10” at narrowest point (6” in R-3 and individual units in R-2 occupancies)
Min. 7.5” at 12” from interior. 26” min width.
Dumbwaiter size is limited to…
limited to 3’x3’ and 4’ tall
What are vertical conveyers?
similar to dumbwaiters but with trays/shelves spaced at regular intervals
What is the max incline in degrees of moving sidewalks? typ width?
may be level or incline to 15 deg max. Typically 40” wide
