Practice Questions for the CompEx Exam
Please note that some of the questions can have multiple answers.
Answers are to be found on the last page.
1. Which of the following is not needed for a fire to take place?
a. Fuel
b. Oxygen
c. An enclosure
d. Spark of sufficient energy
2. Which of the following can ignite a gas atmosphere?
a. Electrical spark
b. Hot surface
c. Battery
d. Intrinsically safe circuit
e. Static electricity
f. Lightning
g. Vehicle
h. Friction
3. The temperature at which a gas ignites spontaneously is called:
a. Ambient temperature
b. Ignition temperature
c. Flash point
d. Thermal temperature
4. Which of the following are commonly adopted?
a. Zone 0, explosive atmosphere for more than 2000 hrs/year
b. Zone 0, explosive atmosphere for more than 1000 hrs/year
c. Zone 2, explosive atmosphere for less than 10 hrs/year
d. Zone 1, explosive atmosphere present between 10 and 1000 hrs/year
5. Which is an example of Group I gas?
a. Methane
b. Propane
c. Ethylene
d. Hydrogen and acetylene
6. The objectives of the ATEX Directive 95 are
a. Removal of technical barriers to trade
b. Incorporation of risk assessments
c. Standardization of 230V ac across Europe
d. Health and safety of workers
7. Concerning ATEX categories, which abbreviation is used for equipment?
a. IEC
b. APL
c. EPL
d. API
8. The term EPL stands for
a. Electrical Protection Level
b. Equipment Protection Level
c. Electrical Protection Load
d. Equipment Pressure Level
9. Ex `n` equipment can be used in
a. Zone 0
b. Zone 0 and Zone 1
c. Zones 0, 1 and 2
d. Zone 2
10. Equipment Protection Level `Gc`/Category 3 equipment can be used in
a. Zone 0
b. Zone 0 and Zone 1
c. Zones 0,1 and 2
d. Zone 2
11. Components which produce sparks, such as contactors and switches, are permited inside Ex `d` enclosures
a. True
b. False
12. Which Standard deals with the general requirements for the Ex`d` protection concept?
a. IEC 60079-1
b. IEC 60079-3
c. IEC 60079-14
d. IEC 60079-17
13. Flameproof equipments is so named because
a. An internal explosion is not permitted
b. An internal explosion is permitted
c. An external explosion is permitted
d. The enclosure is resistant to gas entering the enclosure
14. Ex `d` equipment can be used in
a. Zone 0
b. Zone 1 and 2
c. Zone 2 only
d. Zone 0 and 1
15. A switch is located in a flameproof enclosure less than 2 litres in volume in a IIC environment. The enclosure requires
a. Industrial glands
b. Ex `e` glands
c. Ex `d` Barrier glands
d. An indirect entry Ex `e` chamber fitted with stuffing glands
