CDCP Online Practice Questions and Answers

Correct Answer: D

A design consideration that should be implemented with an Inergen-based fire suppression system is to install pressure relief valves in the room that needs protection. Inergen is a clean agent fire suppression system that uses a mixture of inert gases (nitrogen, argon, and carbon dioxide) to displace the oxygen in the room and extinguish the fire. However, when Inergen is released into the room, it creates a sudden increase in pressure, which can damage the walls, doors, windows, and ceilings of the room. To prevent this, pressure relief valves are required to vent the excess pressure to the outside and maintain a safe pressure level inside the room. Pressure relief valves should be designed and installed in accordance with the relevant standards and codes, such as NFPA 2001 and ISO 14520.

Correct Answer: A

Availability and reliability are two important aspects of data centre performance that measure how often the system is operational and how dependable it is. According to the EPI Data Centre Framework, availability is the percentage of time that a system or component is in an operable state, while reliability is the probability that a system or component will perform its required function under given conditions for a specified period of time. Both availability and reliability can be affected by various factors, such as design, maintenance, human error, power supply, security, etc. One of the factors that can have a significant impact on both availability and reliability is cooling. Cooling is essential for maintaining the optimal temperature and humidity levels for the IT equipment and preventing overheating, which can cause failures, downtime, and reduced lifespan. Inadequate cooling can result from insufficient capacity, poor airflow management, faulty components, or environmental conditions. Inadequate cooling can reduce the availability and reliability of the data centre by increasing the risk of thermal stress, hot spots, performance degradation, and equipment damage. Therefore, cooling is a critical factor that can affect availability and reliability in a data centre.

Correct Answer: A

According to the EPI Data Centre Training Framework, an isolation transformer is a device that transfers electrical power from one circuit to another without changing the voltage or frequency, but providing galvanic isolation. Galvanic isolation means that there is no direct electrical connection between the input and output circuits, which can prevent ground loops, reduce noise, and improve safety. An isolation transformer can also provide voltage stepdown or stepup, create a local ground-bonded neutral, reduce harmonic currents, and provide taps for abnormal mains voltage.

The location of the isolation transformer in relation to the ICT equipment depends on the purpose and design of the transformer. In general, the isolation transformer should be as close as possible to the ICT equipment, but taking into account potential EMF. EMF is a form of electromagnetic interference (EMI) that can affect the performance and reliability of the ICT equipment. The closer the isolation transformer is to the ICT equipment, the shorter the cable length and the lower the voltage drop and power loss4. However, the isolation transformer should also be far enough from the ICT equipment to avoid EMF, which can be reduced by using proper shielding, grounding, and spacing.

The isolation transformer should not be installed as far away as possible to the ICT equipment, as option B suggests, because this would increase the cable length and the voltage drop and power loss. The isolation transformer does not have to be installed within the power entry point of the building, as option C suggests, because this is not a requirement of the electrical code or regulation, and it may not be optimal for the data centre power system. The isolation transformer should not be installed within the rack in which the ICT equipment has been installed, as option D suggests, because this would increase the heat load and the noise level in the rack, and it may not fit in the rack space.

References: 1: EPI Data Centre Training Framework, Module 5: Power, Section 5.4.3: Isolation Transformers, Page 5-38 2: Guidelines for using isolation transformers in data center UPS systems - EEP1, Page 1 3: The Role of Isolation Transformers in Data Center UPS Systems2, Page 2 4: Data Center Transformer | Power Distribution - FGC Construction3, Page 1 5: EPI Data Centre Training Framework, Module 5: Power, Section 5.4.1: Electromagnetic Interference, Page 5-34 : Data centre transformers manufacturers - TMC Transformers4, Page 1 : The Role of Isolation Transformers in Data Center UPS Systems2, Page 25

Correct Answer: B

Cooling capacity is the measure of a cooling system's ability to remove heat from a space. The most preferred unit of measure for cooling capacity is watt (W), which is the SI unit for power. Watt is defined as the amount of energy transferred or converted per unit time. One watt is equal to one joule of energy per second. Using watt as the unit of measure for cooling capacity allows for easy comparison and calculation of the cooling performance and efficiency of different cooling systems.

Other units of measure for cooling capacity are ton, BTU, and horsepower, but they are less common and less convenient than watt. Ton is a unit of measure that describes how much water at freezing temperature can be frozen in 24 hours, equivalent to 3.5 kW or 12,000 BTU/h. BTU (British Thermal Unit) is a unit of measure that describes the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit, equivalent to 0.293 W. Horsepower is a unit of measure that describes the rate at which work is done, equivalent to 746 W.

Correct Answer: C

According to the EPI Data Centre Professional (CDCP? Reference Materials, the recommended number of monitoring points for temperature measurement in a data centre is 3 per rack: one at the top, one at the middle, and one at the bottom. This is to ensure that the temperature distribution within the rack is uniform and within the acceptable range for the equipment. The temperature sensors should be placed at the front of the rack, where the air enters the equipment, and not at the back, where the hot air exits.

Correct Answer: C

Fiber-optic cables use light as the source to transmit data. Light pulses are modulated to carry information through an optical fiber. The light is confined in the core of the fiber by total internal reflection at the core-cladding interface. The light travels along the fiber with minimal loss or interference, making it suitable for long-distance and high-bandwidth applications.

Correct Answer: B

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.

Correct Answer: D

An ultrasonic humidifier is a type of cool mist humidifier that uses a metallic diaphragm that vibrates at high frequencies to create water droplets that are added to the air. A fan projects these droplets into the air as mist, which then evaporates and humidifies the room. This type of humidifier rapidly vibrates the water to create a fog or mist.

Correct Answer: D

The main difference between an Environmental Monitoring System (EMS) and a Building Management System (BMS) is that an EMS monitors only, while a BMS monitors and controls. An EMS is a system that collects and records data from various sensors and devices that measure environmental parameters, such as temperature, humidity, air quality, power, and water. An EMS provides alerts and reports based on the data, but it does not control or adjust the environmental conditions. A BMS is a system that integrates and manages various building systems, such as HVAC, lighting, security, fire, and access. A BMS not only monitors the data from these systems, but also controls and optimizes them to achieve the desired performance and efficiency. A BMS can also communicate with an EMS to receive data and provide feedback.

Correct Answer: A

According to the EPI Data Centre Professional (CDCP? Preparation Guide, failure is defined as "the termination of the ability of a product to perform its required function" (page 9). Failure can occur due to various reasons, such as wear and tear, design flaws, human errors, environmental factors, or external events. Failure can affect the availability, reliability, and performance of a product, system, or service.