Lighting

Question 1

In emergency schemes list three factors that must exist for escape lighting to comply with the Irish standard code of practice for emergency lighting

Answer 1

1. lighting be provided at change of direction
2. lighting be provided at change of level
3. escape routes are indicated clearly
4. Provide lighting along such routes to allow safe movement towards and through exits provided

Question 2

Give one reason why high pressure mercury vapour (MBFU) lamps might not be suitable for use in an industrial loading bay where critical loading operations are carried out continuously.

Answer 2

If power to the lamp is interrupted it may cause considerable outage time as they the lamps need to cool down before they can be restarted

Question 3

Emergency lighting may be supplied from a central battery system or each emergency lighting device e.g Escape route signs can be a self contained device. briefly compare both methods for an emergency lighting installation providing four comparisons

Answer 3

Central battery system. High install cost, high maintenance, failure will disable whole system and long battery life
self contained system. low install cost, low maintenance, independent operation and battery needs to replaced 5-8 years

Question 4

clearly define what is meant by combined (sustained) Emergency luminaire

Answer 4

Containing 2 lamps one is energised from normal lighting supply and second from an emergency light supply

Question 5

Describe briefly the operation of the high pressure mercury vapour (MBF) lamp from the instant of switch on to full illumination.
Give two reasons why MBI mercury halide lamps are suitable for high bay industrial installations, high mast lighting and in sports stadiums (including colour television transmissions)

Answer 5

Electricity passes through the electrodes, ionizing the mercury vapor and creating a dim blue light. As the lamp warms up, it gets brighter and whiter until it reaches full brightness after a few minutes
1.They have good luminous efficacy
2. The lamps have intermediate colour appearance.

Question 6

Define the term illuminance (E) what is the SI unit of measurement

Answer 6

Illuminance (E) is the measure of the amount of light falling on a surface, per unit area. It describes how well-lit a surface is by light from a light source
The SI unit of illuminance is the lux (lx), which is equal to one lumen per square meter

Question 7

You are required to design a lighting control strategy for a commercial building containing offices state four considerations that should be taken in to consideration in account to this design

Answer 7

1.on/iff or dimmable luminares
2.time controlled switches
3. Automatic switching system sensors
4.local manually operated switches

Question 8

list four functions that a test facility on an emergency lighting circuit povide

Answer 8

1. Manual testing
2. Automatic testing
3. Battery Monitoring
   4.Fault Detection and Reporting

Question 9

State four locations where emergency lighting should be provided

Answer 9

1. Staircases
2. Near change of direction
   3 Assembly points
   4.near intersection corridors

Question 10

It is required to install security lighting on the grounds surrounding a factory. State a reason why it might be decided to install the following types of light
1. Low pressure sodium lights (SOX)
2. LED lights operated by PIR

Answer 10

1. SOX lamps are very efficient so could be left on all night even tho there could be bad face recognition it could be enough to deter burglars
2. LED with PIR would instantly turn on when motion is detected they would provide good light if cctv is needed

Question 11

Name a discharge lamp having:
High efficacy but poor colour rendering properties
High efficacy and good colour rendering properties

Answer 11

1. SOX lamp
2. MBI lamp

Question 12

Describe four factors that may affect lamp life of any type of luminaire

Answer 12

1. Frequency of switching on and off
2. operation voltage
3. Ambient operation temperature
4. Lamp orientation