Sprinkler systems

Question 1

What are the three types of pipe systems?

Answer 1

Wet pipe - always filled with water
Dry pipe - filled with air or oxygen, used if freezing risk
Anti-freeze systems - filled with antifreeze + water, used when freezing risk

Question 2

Explain what pre-action and deluge systems are

Answer 2

• Detector and sprinkler activation required, used when equipment sensitive to water
• All sprinklers open when detector or sprinkler activates

Question 3

What are the three types of hazard classification? How is the classification determined? What does the classification of a space determine?

Answer 3

Extra light hazard (ELH)
Ordinary hazard (OH)
Extra high hazard (EHH)
Determined by usage and storage configuration. Determines the number of sprinklers in the design.

Question 4

What are some characteristics of sprinkler systems?

Answer 4

Water distribution, installation orientation, orifice size, temperature rating, thermal sensitivity (RTI), finishes, special services characteristics

Question 5

Explain how a frangible bulb works

Answer 5

Heat makes the liquid expand - the bubble becomes smaller and vanishes - the pressure increases and the bulb bursts - the plug is pushed out and water flows. Colour identifies the temperature rating

Question 6

Explain how a fusible link works

Answer 6

Two pieces of metal are joined by an allow and a constant tension force is applied - heat melts away the alloy and the pieces separate - plug is pushed out and water flows

Question 7

What is the difference in the reliability of the temperature ratings of frangible bulbs and fusible links?

Answer 7

Frangible bulbs are not uniformly heated and are therefore less reliable. Fusible links are uniformly heated and are more reliable.