EXIN EXIN Certifications CDCP Questions & Answers

• Question 51:

  What is the recommended location for the Isolation Transformer in relation to the ICT-Equipment location?

  A. The isolation transformer should be as close as possible to the ICT equipment but taking into account potential EMF.

  B. The isolation transformer should be as far away as possible to the ICT equipment to avoid potential EMF.

  C. The isolation transformer has to be installed within the power entry point of the building due to electrical code (regulation) requirements.

  D. The isolation transformer should be installed within the rack in which the ICT equipment has been installed.

  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

• Question 52:

  What is the main risk for a data centre when the water supply fails?

  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.

  Correct Answer: C

  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.

• Question 53:

  Does unplanned downtime of a data centre have an impact on the business results?

  A. No, because data centres operate independently from the business.

  B. No, unplanned data centre downtime is already financially planned for in the yearly budget planning process.

  C. Yes, data centre downtime can result in business downtime.

  D. Yes, but data centre downtime only impacts the airline industry.

  Correct Answer: C

  Data centres are essential for supporting the IT operations and applications of various businesses across different industries. Data centre downtime can have a negative impact on the business results, such as loss of revenue, customer satisfaction, productivity, reputation, and competitive advantage. According to a web search, the average cost of data centre downtime in 2020 was $8,851 per minute, and the average duration of a data centre outage was 95 minutes1. This means that a typical data centre outage could cost a business over $840,000 in direct and indirect losses1. Therefore, data centre downtime can have a significant impact on the business results, regardless of the industry or sector.

• Question 54:

  Sprinkler heads used in computer rooms activate at what temperature?

  A. 57 °C (135 °F)

  B. 27 °C (81 °F)

  C. 70 C (158 °F)

  D. Only on direct contact with a flame

  Correct 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.

• Question 55:

  Mean time between failures is best considered a measure of:

  A. Size

  B. Cost

  C. Duration

  D. Reliability

  Correct 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.

• Question 56:

  Which formula can be used to define risk?

  A. Risk = Time * Quality

  B. Risk = Security * Criminality

  C. Risk = Impact * Probability

  D. Risk = Probability * Cost

  Correct Answer: C

  According to the CDCP Preparation Guide1, risk can be defined as the product of impact and probability. Impact is the measure of the negative consequences or losses that may result from a risk event, such as downtime, data loss, or damage to the data centre. Probability is the measure of the likelihood or frequency of a risk event occurring, based on historical data, expert judgment, or statistical analysis. By multiplying impact and probability, risk can be quantified and compared, which helps in prioritizing and mitigating the risks. For example, a risk event that has a high impact but a low probability may have the same risk level as a risk event that has a low impact but a high probability.

• Question 57:

  What is the minimum clearance space required below water sprinkler heads and nozzles of gas-based fire suppression systems?

  A. 46 cm / 18 inches

  B. 64 cm / 25 inches

  C. 60 cm / 24 inches

  D. 120 cm / 47 inches

  Correct Answer: A

  The minimum clearance space required below water sprinkler heads and nozzles of gas-based fire suppression systems is 46 cm / 18 inches, according to the CDCP Preparation Guide1 and OSHA regulation 29 CFR 1910.159 ?(10)2. This clearance space is necessary to ensure that the sprinkler spray or gas discharge can reach the fire and cover the protected area effectively. Any material or obstruction below this clearance space can interfere with the sprinkler or gas distribution and reduce the fire suppression performance. Therefore, building owners and managers should ensure that all storage and objects in the data centre are kept below this clearance space, and that the clearance space is maintained at all times.

• Question 58:

  Which one of the following is a factor that can affect Availability and Reliability?

  A. Inadequate Cooling

  B. Employee Salaries

  C. Radio Active Waves

  D. Attenuation

  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.

• Question 59:

  Which design consideration should be implemented with an Inergen-based fire suppression system?

  A. Install protective covers around the nozzles to avoid accidental gas dumps.

  B. Install the gas containers (tanks) close to the data centre.

  C. To use Inergen only for fires which are not related to electrical power.

  D. Pressure relief valves are required in the room that needs protection.

  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.

• Question 60:

  The three elements of the fire triangle are,and. (Choose three.)

  A. Oxygen

  B. Earth

  C. Heat

  D. Water

  E. Fuel

  Correct Answer: ACE

  The fire triangle is a simple model that illustrates the three elements that a fire needs to ignite and sustain:

  oxygen, heat, and fuel. Oxygen is the oxidizing agent that enables the combustion reaction, heat is the energy source that raises the temperature of the fuel to its ignition point, and fuel is the material that reacts with oxygen and releases heat

  and light. Removing any one of these elements can extinguish a fire. For example, water can reduce the heat and the oxygen, sand or soil can smother the fuel and the oxygen, and fire extinguishers can displace the oxygen or lower the

  temperature.

  References: EPI Data Centre Professional (CDCP? Reference Materials, page 66.EPI Data Centre Framework, Module 4: Fire Protection, page 4. 1, 2, 3.