Certified Data Centre Professional (CDCP) Questions and Answers
Sprinkler heads used in computer rooms activate at what temperature?
Options:
57 °C (135 °F)
27 °C (81 °F)
70 C (158 °F)
Only on direct contact with a flame
Answer:
AExplanation:
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.
References:
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 does a Physical Infrastructure consists of in a Data Centre?
Options:
Hub
Switch
Rack
Server
Answer:
CExplanation:
A physical infrastructure in a Data Center consists of racks, which are metal frames used to store and organize server and other IT equipment. The racks are usually arranged in rows and columns, and they can be used to hold servers, storage devices, and other pieces of IT equipment. The racks can also be used to organize cables and other components to ensure that the Data Center is kept organized and efficient.
Which of statements below is true?
Options:
Single-mode cabling can use both LED and laser as a light source.
Single-mode cabling is more expensive than multi-mode cabling.
Multi-mode cabling can cross longer distances.
Multi-mode cabling is more expensive than single-mode cabling.
Answer:
BExplanation:
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 alignmentand 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.
References:
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
Do I need to check the local standards if I already comply to international standards?
Options:
Local standards do not to be checked as some countries have too many local standards, which will slow down the data centre construction.
You need to check the local standards to ensure compliance to these standards.
Compliance to only international standards is good enough as most local standards are derived from international standards.
Data centres only need to comply to international standards since they are connected to a worldwide international network infrastructure.
Answer:
BExplanation:
Data centre design and infrastructure standards can vary from country to country, depending on the local regulations, codes, and practices. Therefore, it is important to check the local standards before designing, building, or operating a data centre in a specific location. Compliance to only international standards may not be sufficient or adequate to meet the local requirements, which could result in legal, financial, or operational risks. For example, some countries may have stricter fire safety, environmental, or energy efficiency standards than the international ones. Some countries may also have different electrical standards, such as voltage, frequency, or plug types. By checking the local standards, you can ensure that your data centre is compliant, safe, and efficient in the local context.
References:
1: Data Center Design: Which Standards to Follow?2, page 1, section 1 3: The Most Important Data Center Design and Infrastructure Codes and Standards4, page 1, section 1 5: Explaining the new family of ISO Data Centre Standards6, page 1, section 1 7: Standards for data centre certification. Is a changing coming?8, page 1, section 1
IP protection grades consist of two numbers.
Which levels of protection do they describe and what is the best protection?
Options:
First digit; protections against the ingress of solid objects. Second digit; protection against ingress of water/fluids. The lower the number the better the level of protection.
First digit; protections against the ingress of solid objects. Second digit; protection against ingress of water/fluids. The higher the number the better the level of protection.
First digit; protections against the ingress of water/fluids. Second digit; protection against ingress of solid objects. The higher the number the better the level of protection.
First digit; protections against the ingress of water/fluids. Second digit; protection against ingress of solid objects. The lower the number the better the level of protection.
Answer:
BExplanation:
IP protection grades are a way of showing the effectiveness of electrical enclosures in blocking foreign bodies such as dust, moisture, liquids, and accidental contact. IP stands for Ingress Protection or International Protection, and it is defined by the international standard IEC 60529. IP ratings consist of the letters IP followed by two digits and an optional letter. The first digit indicates the level of protection the enclosure provides against access to hazardous parts and the ingress of solid foreign objects. The second digit indicates the level of protection the enclosure provides against the ingress of water or fluids. The higher the number, the better the level of protection. For example, IP65 means the enclosure is dust-tight and can withstand water jets from any direction. IP68 means the enclosure is dust-tight and can be submerged in water under specified conditions.
References: EPI Data Centre Training Framework, CDCP Preparation Guide, IP code - Wikipedia, [IP Ratings Explained | Ingress Protection Rating | IP Codes | Updated 2022]
What is the purpose of a service corridor?
Options:
To create a secure and conditioned environment where media can be stored in a controlled manner.
It is a generic name for pathways leading to other rooms that contains facility supporting equipment like the UPS room, battery room, generator room etc.
It provides a safe, vented and secure area where standby generators can operate safely.
It provides a secure area where supporting facilities can be serviced and monitored on a 24x7 basis without disturbing the computer room.
Answer:
DExplanation:
A service corridor is a dedicated space within or adjacent to a data centre that allows access to the supporting facilities, such as power, cooling, fire suppression, security, and cabling systems, without interfering with the computer room operations. A service corridor helps to isolate the noise, vibration, heat, and dust generated by the supporting facilities from the sensitive equipment in the computer room. A service corridor also enhances the safety and efficiency of the maintenance and monitoring activities, as well as the flexibility and scalability of the data centre design.
References: EPI Data Centre Training Framework, CDCP Preparation Guide, Service Corridors Definition | Law Insider
Mean time between failures is best considered a measure of:
Options:
Size
Cost
Duration
Reliability
Answer:
DExplanation:
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.
References: EPI Data Centre Training Framework, CDCP Preparation Guide, Reliability Metrics 101: Mean Time Between Failure (MTBF)
From the list below, which sensor detects smoke the fastest?
Options:
Photoelectric detector
VESDA/HSSD
lonization detector
Sprinkler bulbs
Answer:
BExplanation:
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.
Which source is used in fiber cable to transmit data?
Options:
Signals
Electric
Light
Pulse
Answer:
CExplanation:
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.
References: EPI Data Centre Training Framework, Principle of Data transmission through fiber optic cables, Fiber-optic communication
The UPS vendor is offering the latest model of their UPS to you. The vendor indicates that the UPS is categorized as VFD class.
Is this UPS a fit for your mission-critical data centre?
Options:
Yes
No
Yes, but only if you oversize the battery bank with 10%.
Yes, but only if they install it with a 12-pulse rectifier.
Answer:
BExplanation:
A UPS (uninterruptible power supply) that is categorized as VFD class is not a fit for your mission-critical data centre, because it does not provide adequate protection against voltage and frequency variations. VFD stands for Voltage and Frequency Dependent, which means that the output voltage and frequency of the UPS depend on the input voltage and frequency. VFD UPSs are also known as offline, standby, or line-interactive UPSs. They typically switch to battery power only when the input power fails or goes beyond a certain threshold. However, this switching may cause a brief interruption or a transient in the output power, which can affect the performance and reliability of the ICT equipment. Moreover, VFD UPSs do not filter or regulate the input power, which means that they pass on any voltage or frequency fluctuations, harmonics, or noise to the output power. These power quality issues can also damage or degrade the ICT equipment and the data.
For your mission-critical data centre, you need a UPS that is categorized as VFI class, which stands for Voltage and Frequency Independent. VFI UPSs are also known as online, continuous, or double-conversion UPSs. They provide a constant and clean output power that is independent of the input power. VFI UPSs convert the input AC power to DC power, and then convert it back to AC power with the desired voltage and frequency. This double conversion process isolates the output power from the input power, and eliminates any power quality issues. VFI UPSs also have zero switching time, which means that they do not cause any interruption or transient in the output power when switching to battery power. VFI UPSs are designed to protect the ICT equipment and the data from any adverse effects of voltage and frequency variations, and to ensure the highest level of availability and reliability.
References:
1: CDCP Preparation Guide, page 17, section 2.3.1 2: Understanding UPS Classification: Fuji Electric’s Technical Guide3, page 1, section 1 4: Uninterruptible Power Supplies Key Product Criteria5, page 1, section 1 6: UPS Function: Reduced Input Voltage for VFDs - KEB7, page 1, section 1
Which Class of Fire involves combustible metals or combustible metal alloys such as magnesium, sodium and potassium?
Options:
Class A
Class B
Class C
Class D
Answer:
DExplanation:
Class D fires involve combustible metals or combustible metal alloys such as magnesium, sodium and potassium. These metals can react violently with water, air, or other chemicals, and require special extinguishing agents1
References: 1: EPI Data Centre Professional (CDCP®) Reference Materials, page 16.
What is the recommended location for the Isolation Transformer in relation to the ICT-Equipment location?
Options:
The isolation transformer should be as close as possible to the ICT equipment but taking into account potential EMF.
The isolation transformer should be as far away as possible to the ICT equipment to avoid potential EMF.
The isolation transformer has to be installed within the power entry point of the building due to electrical code (regulation) requirements.
The isolation transformer should be installed within the rack in which the ICT equipment has been installed.
Answer:
AExplanation:
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 isolation1. 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 safety2. 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 voltage3.
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 EMF4. EMF is a form of electromagnetic interference (EMI) that can affect the performance and reliability of the ICT equipment5. 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 spacing5.
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 loss4. 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
Which Class of Fires involves energized electrical equipment?
Options:
Class A
Class B
Class C
Class K
Answer:
CExplanation:
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
What is the most preferred unit of measure for cooling capacity?
Options:
Ton
Watt
BTU
Horsepower
Answer:
BExplanation:
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.
References:
•Data Centre Professional (CDCP®) Reference Materials, page 8, section 2.1.1
•Data Centre Professional (CDCP®) Preparation Guide, page 11, section 2.1.1
•Cooling capacity - Wikipedia
•Air Conditioner BTU Calculator
•Air conditioning 101: Basics, working principle and sizing … - GlobalSpec
•How is cooling capacity measured? – Sage-Advices
•Everything You Need to Know About Cooling Capacity
Which one of the following is a device that uses circulating chilled water to remove heat?
Options:
Computer Room Air Handling Unit (CRAH)
Computer Room Air System Unit (CRAS)
Computer Room Air Suspension Unit (CRAS)
Computer Room Air Suppression Unit (CRAS)
Answer:
AExplanation:
A computer room air handling unit (CRAH) is a device that uses circulating chilled water to remove heat from the data center environment. A CRAH consists of a fan, a coil, and a filter. The fan draws the warm air from the data center and passes it through the coil, where the heat is transferred to the chilled water. The chilled water is supplied by a chiller or a cooling tower, and the cooled air is returned to the data center. A CRAH is different from a computer room air conditioning unit (CRAC), which uses a refrigerant instead of chilled water to cool the air.
References:
•EPI Data Centre Professional (CDCP®) Preparation Guide, page 36
•Chilled Water Systems: Applications and Common Uses
•The Principles of Basic Refrigeration: What is a chiller?
What is the main advantage of busbar trunking compared to stand electrical cabling?
Options:
Busbar trunking is less expensive.
Busbar trunking has a fixed power rating.
Busbar trunking allows for flexibility.
Busbar trunking can be located both overhead and under the raised floor.
Answer:
CExplanation:
Busbar trunking systems are a method of power distribution using rigid copper or aluminium conductors to distribute the power around a building. Busbar trunking systems have many advantages over cables, such as lower space requirements, higher short-circuit strength, lower fire load, and easier installation. One of the main advantages of busbar trunking is that it allows for flexibility in terms of power transmission and distribution. Busbar trunking systems can be easily relocated, modified, or expanded to accommodate changes in the building layout or load demand. Busbar trunking systems can also be fitted with various components, such as tap-off units, elbows, tees, and end feed units, to provide power to different locations and consumers. Busbar trunking systems can also be installed both overhead and under the raised floor, depending on the design and preference of the building.
References: Why I prefer busbar trunking systems more than cables | EEP, Why should you choose Busbar over Cable? - E+I Eng, Busbar VS Cables for Riser Applications - An Electrical Engineer.
Which type of Humidifier suspends quartz lamps over an open pool of water?
Options:
Infrared Humidifiers
Water Canister Humidifier
Steam Canister Humidifier
Ultrasonic Humidifier
Answer:
AExplanation:
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.
References: EPI Data Centre Training Framework, CDCP Preparation Guide, Make Humidification Adjustments | ENERGY STAR
What is the main risk for a data centre when the water supply fails?
Options:
Failure to the water supply could result in IT failure and/or denial of access to operate.
Failure to the water supply could result in DX cooling systems to fail.
Failure to the water supply could cause issues for the cooling of back-up generators.
Failure to the water supply could result in sudden changes of the relative humidity in the Computer room.
Answer:
CExplanation:
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
Starting from which Rating does the requirement of Concurrently Maintainability becomes relevant?
Options:
Rated-4
Rated-3
Rated-2
Rated-1
Answer:
BExplanation:
The requirement of Concurrently Maintainability becomes relevant starting from Rated-3, according to the Uptime Institute Tier Classification System1. Concurrently Maintainability means that any component or system in the data centre can be maintained or replaced without affecting the availability of the IT equipment. This requires having redundant capacity components and multiple independent distribution paths serving the IT equipment. Rated-3 data centres are designed to achieve Concurrently Maintainability and have a minimum uptime of 99.982%. Rated-4 data centres also have Concurrently Maintainability, but they also have Fault Tolerance, which means that they can withstand any single unplanned event without affecting the availability of the IT equipment. Rated-4 data centres have a minimum uptime of 99.995%. Rated-1 and Rated-2 data centres do not have Concurrently Maintainability, as they have only one distribution path serving the IT equipment and no redundant capacity components. Rated-1 data centres have a minimum uptime of 99.671% and Rated-2 data centres have a minimum uptime of 99.741%.
References:
1: Uptime Institute Tier Classification System2, page 1, section 1 2: Data Center Tiers Classification Explained: (Tier 1, 2, 3, 4)3, page 1, section 1 3: Data Center Tier Standards4, page 1, section 1
Which one of the following is a Natural Disaster?
Options:
Grid Failure
Blackouts
Hurricanes
Human Error
Answer:
CExplanation:
According to the CDCP® Preparation Guide, a natural disaster is a catastrophic event that is caused by natural forces and has a significant impact on human lives, property, and environment. Hurricanes are examples of natural disasters, as they are powerful storms that form over warm ocean waters and produce strong winds, heavy rain, storm surges, and flooding. Grid failure, blackouts, and human error are not natural disasters, but rather man-made or technological disasters that result from failures or errors in human systems or activities.
References: CDCP® Preparation Guide, page 9. Natural Disaster Readiness for Data Centers. EM-DAT - The international disaster database. PDC Global - Pacific Disaster Center.
Which design consideration should be implemented with an Inergen-based fire suppression system?
Options:
Install protective covers around the nozzles to avoid accidental gas dumps.
Install the gas containers (tanks) close to the data centre.
To use Inergen only for fires which are not related to electrical power.
Pressure relief valves are required in the room that needs protection.
Answer:
DExplanation:
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.
References:
1: CDCP Preparation Guide, page 24, section 2.4.3 2: Data Center Fire Suppression Systems Bring Unexpected Risk3, page 1, section 1 4: Inergen from Fire Eater - CSC Datacenter5, page 1, section 1 6: Inergen Fire Suppression System7, page 1, section 1