Which type of Humidifier suspends quartz lamps over an open pool of water?
Answer : A
Infrared humidifiers are a type of humidifier that use quartz lamps to heat water in an open pool and evaporate it into the air. They are energy-intensive and require frequent maintenance and cleaning. They are not recommended for data centers, as they can introduce contaminants and bacteria into the air, and increase the risk of fire and electrical hazards.
What is the recommended level of Common Mode Noise (CMN)?
Answer : C
As per Certified Data Centre Professional (CDCP) reference materials, Common Mode Noise (CMN) is a type of electrical noise that appears equally on the line and neutral wires with respect to ground, and it can negatively affect sensitive ICT equipment. Excessive CMN at the rack level can lead to data errors, communication problems, equipment malfunctions, or even hardware damage.
The CDCP training and the official exam preparation guide specify that the preferred level of Common Mode Noise at the rack should be less than 1 Volt, and under no circumstances should it exceed 3 Volts. Keeping CMN at these levels helps ensure the stable and reliable operation of critical data center infrastructure. Higher CMN levels indicate grounding or bonding issues, or possibly interference from electrical or mechanical sources, and must be addressed promptly.
Options A and B (CMN above 5 or 10 Volts) are not acceptable and would present a serious risk to ICT equipment operation and data integrity. Option D is incorrect, as CMN absolutely does affect ICT equipment.
EPI Data Centre Framework: https://www.epi-ap.com/content/31/67/EPI_Data_Centre_Framework
Which one of the following is an Audible Signaling and Notification Device?
Answer : A
According to the CDCP Preparation Guide, an audible signaling and notification device is a device that produces a sound to alert or notify the occupants of a data center of an event or condition. Sirens are examples of such devices, as they can emit loud and distinctive tones to warn of fire, emergency, or security incidents. Strobes, on the other hand, are visual signaling and notification devices that produce flashes of light to attract attention or convey information. Alarms and clocks are not specific types of devices, but rather general terms that can refer to various audible or visual devices.
Which of statements below is true?
Answer : B
Single-mode cabling and multi-mode cabling are two types of fiber optic cables that differ in their core diameter, wavelength, light source, bandwidth, distance, and cost. Single-mode cabling has a smaller core diameter and uses a laser as a light source, which enables it to transmit data over longer distances and higher bandwidths. However, single-mode cabling is also more expensive than multi-mode cabling, because it requires more precise alignment and splicing, and more costly light sources and connectors. Multi-mode cabling has a larger core diameter and uses LEDs or VCSELs as a light source, which makes it cheaper and easier to install and maintain. However, multi-mode cabling also has a shorter distance and lower bandwidth than single-mode cabling, because it suffers from more modal dispersion and attenuation.
1: Data Center Cabling: Single Mode vs Multimode Fibers2, page 1, section 1 3: Single Mode vs Multimode Fiber Cable Guide4, page 1, section 1 5: Single-Mode vs. Multi-Mode Fiber Cables: Explained6, page 1, section 1 7: 2 Types of Fiber Optic Cable: Single Mode vs. Multimode Fiber8, page 1, section 1
Sprinkler heads used in computer rooms activate at what temperature?
Answer : A
Sprinkler heads used in computer rooms activate at 57 C (135 F), which is the standard temperature rating for ordinary sprinklers. This is the temperature at which the heat-sensitive element of the sprinkler head, such as a glass bulb or a fusible link, breaks or melts, allowing water to flow from the sprinkler. Sprinkler heads are designed to activate only when exposed to a fire, not to ambient temperature fluctuations. Therefore, sprinkler heads should be installed at a sufficient distance from the heat sources, such as servers, racks, or ducts, to avoid accidental activation. Sprinkler heads should also be selected and installed in accordance with the relevant standards and codes, such as NFPA 13 and NFPA 75.
1: CDCP Preparation Guide, page 24, section 2.4.3 2: Sprinkler Systems in Data Centers3, page 1, section 1 4: Data Center Fire Protection5, page 1, section 2 6: Data Center Sprinkler System Design7, page 1, section 1
Which one of the following is the last stage in Stages of Combustion?
Answer : D
The last stage in stages of combustion is flaming fire, which occurs when the fuel vapors and oxygen are mixed in the right proportion and ignited by a flame or a spark. Flaming fire is characterized by visible flames, intense heat, and rapid oxidation. Flaming fire can cause severe damage to the data center equipment, personnel, and business continuity. Therefore, it is important to prevent or suppress flaming fire as soon as possible using appropriate fire detection and suppression systems.
* EPI Data Centre Professional (CDCP) Preparation Guide, page 31
* [Fire Detection and Suppression Systems for Data Centers]
Mean time between failures is best considered a measure of:
Answer : D
Mean time between failures (MTBF) is a measure of the reliability of a system or component. It represents the average time that a system or component will operate before it fails. The higher the MTBF, the more reliable the system or component is. MTBF is calculated by dividing the total time of operation by the number of failures that occur during that time. MTBF is used to compare the reliability of similar systems or components, and to help with maintenance planning, inventory management, and system design.