Class C fires involve energized electrical equipment, such as computers, servers, switches, cables, and wiring. These fires require the use of non-conductive extinguishing agents, such as carbon dioxide, dry chemical, or clean agent, to prevent electrical shock and damage to the equipment. Water-based extinguishers, such as Class A or K, are not suitable for Class C fires, as water can conduct electricity and cause electrocution or short circuits.
References: EPI Data Centre Training Framework, CDCP Preparation Guide, ABCs of Fire Extinguishers
Question 2
What is the main risk for a data centre when the water supply fails?
Options:
A.
Failure to the water supply could result in IT failure and/or denial of access to operate.
B.
Failure to the water supply could result in DX cooling systems to fail.
C.
Failure to the water supply could cause issues for the cooling of back-up generators.
D.
Failure to the water supply could result in sudden changes of the relative humidity in the Computer room.
Answer:
C
Explanation:
Explanation:
Back-up generators are essential for providing power to the data centre in case of a utility outage. However, back-up generators also generate a lot of heat, which needs to be dissipated by a cooling system. The cooling system may rely on water supply, either from the municipal network or from a dedicated tank. If the water supply fails, the cooling system may not function properly, leading to overheating and potential damage to the generators. This could compromise the reliability and availability of the data centre power supply and cause downtime or data loss.
References:
1: CDCP Preparation Guide, page 18, section 2.3.2 2: Data Center Generator Cooling Systems3, page 1, section 1 4: Data Center Cooling Systems5, page 1, section 1
Question 3
From the list below, which sensor detects smoke the fastest?
Options:
A.
Photoelectric detector
B.
VESDA/HSSD
C.
lonization detector
D.
Sprinkler bulbs
Answer:
B
Explanation:
Explanation:
VESDA (Very Early Smoke Detection Apparatus) or HSSD (High Sensitivity Smoke Detection) systems are the fastest smoke sensors among the options listed. These systems use a network of pipes to draw air samples from the protected area and analyze them using a laser-based detection chamber. VESDA/HSSD systems can detect smoke at very low concentrations, typically in the range of 0.005 to 20 percent obscuration per meter. This means they can provide early warning of a fire before it becomes visible or spreads. VESDA/HSSD systems are ideal for data centers and other critical facilities that require high levels of fire protection and minimal downtime.
References: VESDA Smoke Detection Systems - Xtralis, HSSD Smoke Detection Systems - Fire Protection Online, Smoke Detection in Data Centers - Siemens.