I passed the Electrical PE on the first try in. It's now been a few years and I have several engineers-in-training prepping for their PE tests. As I give them study resources I'll try and post the material here. Maybe I'll go back and update books that have new editions more applicable to this year's PE test.
The The Lighting Handbook: Reference and Application (Iesna Lighting Handbook)
is now on its 10th Edition. They really should have made this thing two volumes as it is enormous. The IES Handbook itself says there is virtually no role for hand calculations in modern illuminating engineering, but they did have one on the PE so it's worth having the equations from Chapter 10 "Calculation of Light and Its Effects" handy. I know I never do hand calcs at work as there is far more sophisticated software, so having the book was good. I got the general knowledge question without the book. The hand calculation one was basically asking you to demonstrate knowledge of the lumen method by calculating the approximate foot-candles a certain light would provide to a space. I share an example below from a UK website that had a couple good examples.
Another source of practice questions comes from the National Council on Qualifications for the Lighting Professions Lighting Certified Professional exam. Their test prep handbook has 15 example questions that if you do lighting design at all professionally you should know the answers to off the top of your head or you should do enough reading from the IES handbook to learn the answers just to get a basic fluency in lighting. The NCQLP handbook can be found on their website.
Example Questions from 2015 NCQLP Candidate handbook
1. When evaluating daylighting systems in terms of glare, the
MOST important illumination conditions to be evaluated
are those occurring
A. when cooling loads due to solar gains are greatest.
B. when direct sunlight would penetrate the
fenestration.
C. at 2-hour intervals from sunrise to solar noon.
D. at the solstices and the equinoxes.
2. The ratio of mean lumens to rated lumens indicates
A. ballast factor.
B. voltage drop.
C. lamp lumen depreciation.
D. luminaire dirt depreciation.
3. The term luminaire refers to a
A. lighting unit exclusively for roadway illumination.
B. lighting unit exclusively for interior illumination.
C. complete lighting unit without lamps and ballasts.
D. complete lighting unit including lamps and ballasts.
4. Which of the following is the BEST definition of
illuminance?
A. time rate of flow of light energy
B. luminous flux incident on an object per unit area
C. flux density emitted from an object without regard for
direction
D. flux density emitted from an object in a given
direction
5. A hospital is experiencing RFI problems with its radiology
equipment. The lighting system in this area has been
identified as a 2 x 4 lensed troffer using F32T8 lamps and
an electronic ballast. Which of the following could be
attributed to the interference?
A. size of the luminaire
B. proximity of the luminaire
C. spectral output from the lamp
D. total harmonic distortion from the ballast
6. Two objects match in color appearance under a
fluorescent light source with a specific CRI and correlated
color temperature. Under which of the following light
sources would these objects MOST likely be expected to
match?
A. LED
B. halogen IR
C. reference lamp
D. ceramic metal halide
7. In barrier-free public buildings where emergency lighting
codes prevail, illuminated exit signs must provide an extra
warning for visually impaired visitors by
A. flashing.
B. incorporating braille letters.
C. using high-luminance lamps.
D. beeping loudly.
8. The lamp designations ES, SS, EW, and WM are for
fluorescent lamps that
A. are reduced wattage alternatives.
B. use energy-efficient ballasts.
C. require electronic ballasts.
D. have low acquisition costs.
9. Which of the following is a CIE/IESNA luminaire
distribution classification category?
A. semi-indirect
B. concentrating
C. forward throw
D. wall wash
10. A ray of incident light being reflected in one distinct
direction is representative of what type of reflection?
A. spread
B. diffuse
C. semi-specular
D. specular
11. In life-cycling costing, the measure of results is expressed
in
A. deffered expenses.
B. kWh saved.
C. net present value.
D. risk factors.
12. Group relamping of fluorescent luminaires is generally
recommended
A. upon change of occupancy.
B. at 60 to 70% of rated life.
C. at a 20% failure rate.
D. every 5 years.
13. Before construction is completed, an electrical contractor
should notify the lighting designer of the anticipated
completion date so that
A. the designer can walk through with the electrical
inspector.
B. ballasts can be calibrated by the electrical engineer.
C. a representative of the design office can help schedule
installation.
D. a schedule can be set for aiming and adjusting
fixtures.
14. Before a lighting system can be commissioned, the punch
list
A. must be completed and corrected.
B. must be certified by the inspector.
C. must be approved by the owner.
D. cannot be modified by the designer.
15. To ensure a lighting design’s projected energy savings are
realized after installation, a lighting practitioner must
A. adjust occupancy sensors and dimmers.
B. focus the adjustable accent lights.
C. finalize the punch list.
D. inspect the branch circuit wiring.
Example Calculating using the Lumen Method The The Lighting Handbook: Reference and Application (Iesna Lighting Handbook)
is now on its 10th Edition. They really should have made this thing two volumes as it is enormous. The IES Handbook itself says there is virtually no role for hand calculations in modern illuminating engineering, but they did have one on the PE so it's worth having the equations from Chapter 10 "Calculation of Light and Its Effects" handy. I know I never do hand calcs at work as there is far more sophisticated software, so having the book was good. I got the general knowledge question without the book. The hand calculation one was basically asking you to demonstrate knowledge of the lumen method by calculating the approximate foot-candles a certain light would provide to a space. I share an example below from a UK website that had a couple good examples.Another source of practice questions comes from the National Council on Qualifications for the Lighting Professions Lighting Certified Professional exam. Their test prep handbook has 15 example questions that if you do lighting design at all professionally you should know the answers to off the top of your head or you should do enough reading from the IES handbook to learn the answers just to get a basic fluency in lighting. The NCQLP handbook can be found on their website.
Example Questions from 2015 NCQLP Candidate handbook
1. When evaluating daylighting systems in terms of glare, the
MOST important illumination conditions to be evaluated
are those occurring
A. when cooling loads due to solar gains are greatest.
B. when direct sunlight would penetrate the
fenestration.
C. at 2-hour intervals from sunrise to solar noon.
D. at the solstices and the equinoxes.
2. The ratio of mean lumens to rated lumens indicates
A. ballast factor.
B. voltage drop.
C. lamp lumen depreciation.
D. luminaire dirt depreciation.
3. The term luminaire refers to a
A. lighting unit exclusively for roadway illumination.
B. lighting unit exclusively for interior illumination.
C. complete lighting unit without lamps and ballasts.
D. complete lighting unit including lamps and ballasts.
4. Which of the following is the BEST definition of
illuminance?
A. time rate of flow of light energy
B. luminous flux incident on an object per unit area
C. flux density emitted from an object without regard for
direction
D. flux density emitted from an object in a given
direction
5. A hospital is experiencing RFI problems with its radiology
equipment. The lighting system in this area has been
identified as a 2 x 4 lensed troffer using F32T8 lamps and
an electronic ballast. Which of the following could be
attributed to the interference?
A. size of the luminaire
B. proximity of the luminaire
C. spectral output from the lamp
D. total harmonic distortion from the ballast
6. Two objects match in color appearance under a
fluorescent light source with a specific CRI and correlated
color temperature. Under which of the following light
sources would these objects MOST likely be expected to
match?
A. LED
B. halogen IR
C. reference lamp
D. ceramic metal halide
7. In barrier-free public buildings where emergency lighting
codes prevail, illuminated exit signs must provide an extra
warning for visually impaired visitors by
A. flashing.
B. incorporating braille letters.
C. using high-luminance lamps.
D. beeping loudly.
8. The lamp designations ES, SS, EW, and WM are for
fluorescent lamps that
A. are reduced wattage alternatives.
B. use energy-efficient ballasts.
C. require electronic ballasts.
D. have low acquisition costs.
9. Which of the following is a CIE/IESNA luminaire
distribution classification category?
A. semi-indirect
B. concentrating
C. forward throw
D. wall wash
10. A ray of incident light being reflected in one distinct
direction is representative of what type of reflection?
A. spread
B. diffuse
C. semi-specular
D. specular
11. In life-cycling costing, the measure of results is expressed
in
A. deffered expenses.
B. kWh saved.
C. net present value.
D. risk factors.
12. Group relamping of fluorescent luminaires is generally
recommended
A. upon change of occupancy.
B. at 60 to 70% of rated life.
C. at a 20% failure rate.
D. every 5 years.
13. Before construction is completed, an electrical contractor
should notify the lighting designer of the anticipated
completion date so that
A. the designer can walk through with the electrical
inspector.
B. ballasts can be calibrated by the electrical engineer.
C. a representative of the design office can help schedule
installation.
D. a schedule can be set for aiming and adjusting
fixtures.
14. Before a lighting system can be commissioned, the punch
list
A. must be completed and corrected.
B. must be certified by the inspector.
C. must be approved by the owner.
D. cannot be modified by the designer.
15. To ensure a lighting design’s projected energy savings are
realized after installation, a lighting practitioner must
A. adjust occupancy sensors and dimmers.
B. focus the adjustable accent lights.
C. finalize the punch list.
D. inspect the branch circuit wiring.
The method is a commonly used technique of lighting design, which is valid, if the light fittings (luminaires) are to be mounted overhead in a regular pattern. The luminous flux output (lumens) of each lamp needs to be known as well as details of the luminaires and the room surfaces. Usually the illuminance is already specified e.g. office 500 lux, kitchen 300 lux, the designer chooses suitable luminaires and then wishes to know how many are required.
The number of lamps is given by the formula: where,
- N = number of lamps required.
- E = illuminance level required (lux)
- A = area at working plane height (m2)
- F = average luminous flux from each lamp (lm)
- UF= utilisation factor, an allowance for the light distribution of the luminaire and the room surfaces
- MF= maintenance factor, an allowance for reduced light output because of deterioration and dirt
