Which Class of Fires involves energized electrical equipment?
Class A
Class B
Class C
Class K
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
By what are magnetic fields of the type 'H' or 'B' created?
Magnetic fields are created when an electric current flows; the greater the current, the stronger the magnetic field.
Magnetic fields are created by the magnetic flux of the earth which varies per month.
Magnetic fields are created by voltage; the greater the voltage, the stronger the magnetic field.
Magnetic fields are created when there is a high level of common mode noise (CMN); the greater the common mode noise (CMN), the stronger the magnetic field.
According to the CDCP Preparation Guide1, magnetic fields of the type ‘H’ or ‘B’ are created when an electric current flows through a conductor, such as a wire or a coil. The magnetic field strength ‘H’ is proportional to the current ‘I’ and the number of turns ‘N’ of the coil, and inversely proportional to the length ‘l’ of the coil. The magnetic flux density ‘B’ is proportional to the magnetic field strength ‘H’ and the permeability ‘μ’ of the medium in which the magnetic field exists. The greater the current, the stronger the magnetic field and the magnetic flux density. The relationship between ‘H’, ‘B’, ‘I’, ‘N’, ‘l’, and ‘μ’ can be expressed by the following equations:
H = N I / l
B =μH
References:
1: CDCP Preparation Guide, page 23, section 2.4.2.1 2: Difference between B and H in magnetic fields?3, page 1, section 1 4: Magnetic field | Definition & Facts5, page 1, section 1
When having two non-synchronized power sources, the ATS / STS need to be of the type:
Break before make.
Make before break.
Both make before break or break before make can be used.
Both an ATS and STS can never handle two non-synchronized sources.
When having two non-synchronized power sources, the ATS / STS need to be of the type break before make, which means that the switch disconnects from one source before connecting to the other source. This prevents any short circuit, back feed, or phase mismatch that could occur if the two sources were connected simultaneously. Break before make switches are also known as open transition switches, because they create a brief interruption in the power supply during the switching process. This interruption is usually acceptable for most ICT equipment, as they have internal power supplies or batteries that can handle the transient. However, if the interruption is not acceptable, then the two power sources need to be synchronized before switching, which requires a make before break switch, also known as a closed transition switch. Make before break switches connect to the second source before disconnecting from the first source, which ensures a seamless transfer of power without any interruption. However, make before break switches require that the two sources have the same voltage, frequency, and phase, which can be achieved by using a synchronization module or a phase-locked loop.
References:
1: CDCP Preparation Guide, page 17, section 2.3.1 2: STS in data centres - Borri3, page 1, section 1 4: Using Static Transfer Switches to Enhance Data Center … - Donwil5, page 1, section 1 6: What is an Automatic Transfer Switch (Power)? | Ethan Banks7, page 1, section 1
What is the recommended location for the Isolation Transformer in relation to the ICT-Equipment location?
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.
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 one of the following represents the three elements (oxygen, heat and fuel) to interact in order for the fire to exist?
The Fire Hexagon
The Fire Class
The Fire Triangle
The Fire Technology
The fire triangle is a simple model that illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elementsare present and combined in the right mixture. A fire can be prevented or extinguished by removing any one of the elements in the fire triangle.
References: EPI Data Centre Professional (CDCP®) Preparation Guide, page 9; Fire triangle - Wikipedia; The Fire Triangle Explained - Fire Action
The temperature and humidity values indicated on the display of the Computer room air conditioner unit are the values measured at which point?
It is the average value between the intake and exhaust (outlet) of the air conditioner.
It is the value measured at the intake of the air conditioner.
It is the value measured at the exhaust (outlet) of the air conditioner.
It is the value measured at the front of the rack of the aisle the air conditioner is situated.
According to the IBM document on temperature and humidity design criteria1, the temperature and humidity values indicated on the display of the computer room air conditioner unit are the values measured at the intake of the air conditioner. This is because the intake is where the air conditioner draws the air from the computer room and cools and dehumidifies it before sending it back to the computer room. The display shows the current conditions of the computer room air, which are used to adjust the cooling and dehumidifying operations of the air conditioner. The values measured at the exhaust (outlet) of the air conditioner are not displayed, as they are not relevant for the computer room environment. The values measured at the front of the rack of the aisle the air conditioner is situated are also not displayed, as they may vary depending on the distance and location of the rack. The average value between the intake and exhaust (outlet) of the air conditioner is not displayed, as it does not reflect the actual conditions of the computer room air or the air conditioner performance.
References: 1: Temperature and humidity design criteria - IBM
What needs to be installed in the battery room when using Lithium-ion batteries?
A battery management system to monitor and prevent unsafe temperatures during charging/discharging.
High capacity air-conditioning equipment since Lithium-ion batteries are sensitive to high temperatures, which can reduce their lifetime.
A proper ventilation system since Lithium-ion batteries produce highly flammable Hydrogen gas during charging.
A proper supply of distilled water.
According to the EPI Data Centre Training Framework, lithium-ion batteries are becoming more popular in data centres due to their higher energy density, longer lifespan, and lower maintenance costs compared to lead-acid batteries1. However, lithium-ion batteries also have some drawbacks, such as higher initial cost, stricter safety requirements, and potential thermal runaway risks1. Therefore, a battery management system (BMS) is essential to monitor and control the voltage, current, temperature, and state of charge of each battery cell or module, and to prevent overcharging, over-discharging, or overheating23. A BMS can also communicate with the UPS system and provide information on the battery status, performance, and health2.
References: 1: EPI Data Centre Training Framework, Module 5: Power, Section 5.3.2: Battery Technologies, Page 5-19 2: Benefits of Lithium-ion batteries for data centers at the edge,Data Center Knowledge, Page 1 3: Lithium-Ion Batteries in Data Centers, Data Center Systems, Inc, Page 1
From the list below, which sensor detects smoke the fastest?
Photoelectric detector
VESDA/HSSD
lonization detector
Sprinkler bulbs
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.
What is the primary reason to install a monitoring system in the data centre?
To notice abnormalities early so that actions can be taken to avoid disasters
To create a proper asset database
To implement automated change management
To be able to collect data for capacity planning
The primary reason to install a monitoring system in the data centre is to notice abnormalities early so that actions can be taken to avoid disasters, according to the CDCP Preparation Guide1 and various web sources234. A monitoring system is a system that collects and analyzes data about the power, cooling, environmental, and security conditions in the data centre, and alerts the operators or managers about any issues or threats that may affect the performance, availability, or reliability of the data centre. A monitoring system can help to prevent or minimize the impact of disasters, such as power outages, fire, water damage, overheating, equipment failure, or cyberattacks, by providing timely and accurate information that enables fast and corrective action. A monitoring system can also help to improve the energy efficiency, capacity planning, and asset management of the data centre, by providing useful insights and trends that support informed decision making.
References:
1: CDCP Preparation Guide, page 21, section 2.3.5 2: Improving Data Center Management and Monitoring5, page 1, section 1 3: Guide to Data Center Monitoring6, page 1, section 1 4: Why Data Center Monitoring is Essential7, page 1, section 1
IP protection grades consist of two numbers.
Which levels of protection do they describe and what is the best protection?
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.
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]
The three elements of the fire triangle are,and. (Choose three.)
Oxygen
Earth
Heat
Water
Fuel
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.
What is the main risk for a data centre when the water supply fails?
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.
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
is the degree to which a system or component is operational and accessibility when required for use.
Scalability
Agility
Reliability
Availability
Availability is the degree to which a system, product or component is operational and accessible when required for use. It is one of the attributes of reliability, which is the ability of a system or component to perform its required functions under stated conditions for a specified period of time. Availability can be calculated as the ratio of the expected value of the uptime (the time when the system is functional) to the total time (uptime plus downtime) of a system or component. Availability can also be influenced by factors such as maintainability, fault tolerance, redundancy, diagnostics, and logistics.
References: EPI Data Centre Professional (CDCP®) Preparation Guide, page 8; Availability - Wikipedia; Reliability - ISO 25000.
An optical fiber cable comes with the specifications 50/125 um.
What do the numbers represent?
The first number represents the distance for a 10 Gb/s connection; the second number represents the distance for a 1 Gb/s connection.
The first number represents the diameter of the core; the second number represents the diameter of the cladding in microns.
The first number represents the diameter of the core; the second number represents the actual diameter cable including the buffer and jacket.
The first number represents the required distance to single-phase power cabling; the second number represents the required distance to three-phase cabling.
Optical fiber cables are composed of a core, a cladding, and a coating. The core is the central part of the fiber that carries the light signal. The cladding is the layer surrounding the core that reflects the light back into the core and prevents signal loss. The coating is the protective layer that covers the cladding and provides mechanical strength and environmental protection. The specifications of an optical fiber cable indicate the dimensions of the core and the cladding in microns (μm), which are one millionth of a meter. For example, a 50/125 μm cable has a core diameter of 50 μm and a cladding diameter of 125 μm. The coating diameter is usually 250 μm, but it is not part of the specifications.
References: Multimode Optical Fiber Selection & Specification - Corning, Optical Fiber OM3 (50/125µm Multimode Fiber), 50/125 Graded-Index OM2 Optical Fiber - OFS
Which Class of Fire involves combustible metals or combustible metal alloys such as magnesium, sodium and potassium?
Class A
Class B
Class C
Class D
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 are the four main components of a refrigeration circuit?
Evaporation, membrane filter, monitor sensor, pressure valve
Evaporator, compressor, condenser, expansion valve
Condenser, expansion valve, buffer tank, de-icing unit
Thermostat, monitoring interface, indoor unit, outdoor unit
The four main components of a refrigeration circuit are the evaporator, the compressor, the condenser, and the expansion valve, according to the CDCP Preparation Guide1 and various web sources234. A refrigeration circuit is a system that transfers heat from a low-temperature region to a high-temperature region, using a working fluid called refrigerant. The refrigeration circuit operates in a closed loop, where the refrigerant changes its state from liquid to vapor and back to liquid, while absorbing and releasing heat. The four main components of the refrigeration circuit perform the following functions:
•The evaporator is a heat exchanger that absorbs heat from the low-temperature region, such as the data centre room, and transfers it to the refrigerant. The refrigerant enters the evaporator as a low-pressure, low-temperature liquid, and leaves the evaporator as a low-pressure, low-temperature vapor.
•The compressor is a mechanical device that increases the pressure and temperature of the refrigerant vapor. The refrigerant enters the compressor as a low-pressure, low-temperature vapor, and leaves the compressor as a high-pressure, high-temperature vapor.
•The condenser is another heat exchanger that releases heat from the refrigerant to the high-temperature region, such as the outside air or water. The refrigerant enters the condenser as a high-pressure, high-temperature vapor, and leaves the condenser as a high-pressure, low-temperature liquid.
•The expansion valve is a device that reduces the pressure and temperature of the refrigerant liquid. The refrigerant enters the expansion valve as a high-pressure, low-temperature liquid, and leaves the expansion valve as a low-pressure, low-temperature liquid. The expansion valve also controls the flow of the refrigerant into the evaporator, depending on the cooling load.
References:
1: CDCP Preparation Guide, page 19, section 2.3.3 2: The Refrigeration Cycle5, page 1, section 1 3: Fundamentals of Cooling in Data Center6, page 1, section 1 4: The Refrigeration System, Its Four Main Components, And Their Functions7, page 1, section 1
Which one of the following is a device that uses circulating chilled water to remove heat?
Computer Room Air Handling Unit (CRAH)
Computer Room Air System Unit (CRAS)
Computer Room Air Suspension Unit (CRAS)
Computer Room Air Suppression Unit (CRAS)
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?
Which design consideration should be implemented with an Inergen-based fire suppression system?
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.
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
systems are designed specifically to protect the structure of a building.
Pro-inert
Inergen
Water sprinkler
Total Flooding
Water sprinkler systems are designed to protect the structure of a building from fire by suppressing or extinguishing the flames with water. Water sprinkler systems are typically installed in the ceiling or walls of a building and are activated by heat or smoke detectors. Water sprinkler systems can reduce the risk of fire spreading and causing structural damage to the building.
References:
•EPI Data Centre Professional (CDCP®) Preparation Guide, page 28
•Fire Protection Systems for Data Centers | EPI
Which one of the following is used in Measuring Business Value?
Regeneration Cost
Scalability
Reliability
Upfront Cost
Measuring business value is the process of assessing the benefits and costs of IT investments and initiatives in relation to the strategic objectives and priorities of the organization. One of the factors that can be used to measure business value is scalability, which is the ability of a system or component to handle increasing workloads or demands without compromising performance, quality, or functionality. Scalability is important for business value because it enables the organization to adapt to changing market conditions, customer expectations, and growth opportunities. Scalability can also reduce operational costs, increase efficiency, and improve customer satisfaction. Therefore, scalability is one of the factors that can be used in measuring business value.
References:
•EPI Data Centre Training Framework1
•EPI Data Centre Competence Framework2
•Measuring the Business Value of IT3
•How to Measure the Business Value with Effective Data Quality Governance
•7 Rules for Demonstrating the Business Value of IT
What is the purpose of a service corridor?
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.
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
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