Question #1
Management has requested a 15-minute battery bank assuming full load on the UPS.
The UPS vendor has provided the following specifications of the UPS:
• Rated power: 30 kVA
• Rectifier input voltage: 400 V/3 phase
• Rectifier input power factor: 0.8
• Battery rated voltage: 384 V
• Number of cells: 192
• End of discharge voltage: 308 V
• Inverter output voltage: 400 V/3 phase
• Inverter output power factor: 0.8
What information is missing to perform the battery calculation?
- A . UPS efficiency
- B . Inverter efficiency
- C . Load imbalance on the phases
- D . Available battery charging current
Correct Answer: A
A
Explanation:
To determine the required capacity of the battery bank for the 15-minute runtime at full load, one must know the total power requirement that the battery bank must supply. The specifications provided include most of the necessary details, such as rated power, input voltage, battery voltage, and discharge voltage. However, one critical piece of information is missing: the UPS efficiency.
Detailed Explanation
In a data center UPS system, the battery bank is designed to supply power for a set duration when there is an input power failure. The UPS efficiency affects the actual power the UPS can deliver to the load compared to the power it draws from the batteries. The efficiency factor is necessary to accurately calculate the required capacity of the battery bank since it determines how much input power is needed from the batteries to supply the load at full capacity. The formula typically used to determine battery capacity involves factoring in UPS efficiency, as it allows you to understand the losses within the UPS system.
If UPS efficiency is not considered, there would be an inaccurate estimation of the actual power needed from the batteries. For instance, if a UPS has 90% efficiency, only 90% of the power drawn from the batteries reaches the load. Without knowing this efficiency, it is not possible to calculate the battery bank size accurately, as you cannot accurately estimate the losses within the UPS itself.
EPI Data Center Specialist References:
According to EPI Data Center Specialist training, understanding the UPS efficiency is essential for battery sizing. Without it, the calculations could lead to either under sizing or oversizing the battery bank, which affects both reliability and cost-effectiveness of the UPS system. The EPI Data Center Specialist course emphasizes that battery sizing must account for all losses within the UPS system, with efficiency being a primary factor in these calculations.
A
Explanation:
To determine the required capacity of the battery bank for the 15-minute runtime at full load, one must know the total power requirement that the battery bank must supply. The specifications provided include most of the necessary details, such as rated power, input voltage, battery voltage, and discharge voltage. However, one critical piece of information is missing: the UPS efficiency.
Detailed Explanation
In a data center UPS system, the battery bank is designed to supply power for a set duration when there is an input power failure. The UPS efficiency affects the actual power the UPS can deliver to the load compared to the power it draws from the batteries. The efficiency factor is necessary to accurately calculate the required capacity of the battery bank since it determines how much input power is needed from the batteries to supply the load at full capacity. The formula typically used to determine battery capacity involves factoring in UPS efficiency, as it allows you to understand the losses within the UPS system.
If UPS efficiency is not considered, there would be an inaccurate estimation of the actual power needed from the batteries. For instance, if a UPS has 90% efficiency, only 90% of the power drawn from the batteries reaches the load. Without knowing this efficiency, it is not possible to calculate the battery bank size accurately, as you cannot accurately estimate the losses within the UPS itself.
EPI Data Center Specialist References:
According to EPI Data Center Specialist training, understanding the UPS efficiency is essential for battery sizing. Without it, the calculations could lead to either under sizing or oversizing the battery bank, which affects both reliability and cost-effectiveness of the UPS system. The EPI Data Center Specialist course emphasizes that battery sizing must account for all losses within the UPS system, with efficiency being a primary factor in these calculations.
Question #2
The pipes of a VESDA smoke detection system are installed at the air intake of the air conditioner inside the computer room.
Is this a good practice from an early smoke detection point of view?
- A . It depends on the type of gas-based fire suppression which will be installed.
- B . Yes, as this reduces the amount of piping to be installed in the data center, as all air will go through the air conditioner.
- C . No, the piping should be installed at the air exhaust of the air conditioner, as there can also be a fire inside the air conditioner itself.
- D . No, it will give a longer reaction time for the smoke detection system and there might also be bypass airflow.
Correct Answer: D
D
Explanation:
For optimal early smoke detection in a data center, it is crucial that the Very Early Smoke Detection Apparatus (VESDA) system be installed at locations where smoke will be detected as soon as it appears. Positioning the VESDA pipes at the air intake of the air conditioner inside the computer room is not ideal. This placement could result in a delayed detection response and the potential for bypass airflow to occur, which would impede the system’s ability to detect smoke effectively .
Detailed Explanation
When VESDA pipes are installed at the air intake, the detection system relies on the smoke to be drawn into the air conditioning unit before detection can occur. This setup increases the reaction time as the smoke has to travel through the intake and get processed by the air conditioner.
Furthermore, bypass airflow―a phenomenon where not all the air containing smoke particles passes through the VESDA pipes―could also delay or even prevent the system from detecting smoke early. Ideally, VESDA pipes should be positioned where smoke is likely to accumulate first, such as near the ceiling or in the return airflow path to detect smoke at the earliest possible stage. This ensures that the detection system can quickly trigger alarms, providing more time to address potential fire hazards.
EPI Data Center Specialist References:
EPI Data Center Specialist training highlights that smoke detection should prioritize early response capabilities to maximize safety. The preferred installation for VESDA pipes is generally at points where smoke would naturally accumulate, rather than relying on air conditioning intakes where airflow can vary and delay detection. In their course materials, EPI emphasizes minimizing reaction time and reducing the impact of airflow dynamics on smoke detection efficiency.
D
Explanation:
For optimal early smoke detection in a data center, it is crucial that the Very Early Smoke Detection Apparatus (VESDA) system be installed at locations where smoke will be detected as soon as it appears. Positioning the VESDA pipes at the air intake of the air conditioner inside the computer room is not ideal. This placement could result in a delayed detection response and the potential for bypass airflow to occur, which would impede the system’s ability to detect smoke effectively .
Detailed Explanation
When VESDA pipes are installed at the air intake, the detection system relies on the smoke to be drawn into the air conditioning unit before detection can occur. This setup increases the reaction time as the smoke has to travel through the intake and get processed by the air conditioner.
Furthermore, bypass airflow―a phenomenon where not all the air containing smoke particles passes through the VESDA pipes―could also delay or even prevent the system from detecting smoke early. Ideally, VESDA pipes should be positioned where smoke is likely to accumulate first, such as near the ceiling or in the return airflow path to detect smoke at the earliest possible stage. This ensures that the detection system can quickly trigger alarms, providing more time to address potential fire hazards.
EPI Data Center Specialist References:
EPI Data Center Specialist training highlights that smoke detection should prioritize early response capabilities to maximize safety. The preferred installation for VESDA pipes is generally at points where smoke would naturally accumulate, rather than relying on air conditioning intakes where airflow can vary and delay detection. In their course materials, EPI emphasizes minimizing reaction time and reducing the impact of airflow dynamics on smoke detection efficiency.
Question #3
You need to determine the strategy for the cooling audit. All the servers are based on a front-to-rear (F-R) airflow design.
Which location for the temperature/humidity measurement should you recommend for the audit?
- A . At the back/rear of the server at 50 mm/2 inch
- B . At 1.5 meters/5 feet above the floor in the middle of the cold aisle
- C . At the front/intake of the server at 50 mm/2 inch
- D . At 1.5 meters/5 feet above the floor in the middle of the hot aisle
Correct Answer: C
C
Explanation:
For a cooling audit in a data center, it is essential to measure temperature and humidity where air enters the servers to accurately assess cooling performance. In this case, since all servers have a front-to-rear (F-R) airflow design, measuring at the front/intake of the server will provide a precise understanding of the cooling conditions that the equipment is experiencing .
Detailed Explanation
Servers with a front-to-rear airflow design draw in cool air from the cold aisle at the front, which is then exhausted into the hot aisle at the rear. By measuring temperature and humidity 50 mm/2 inches from the front intake, you gather data on the air conditions right before it enters the servers, providing an accurate representation of the cooling environment as it directly impacts the equipment.
Measuring in the cold aisle at the front intake ensures that the readings reflect the actual conditions of the incoming air that the servers depend on for effective cooling. This approach is consistent with best practices for maintaining thermal conditions in a data center, as it helps confirm that the cooling systems are delivering air within the required temperature and humidity specifications.
EPI Data Center Specialist References:
According to the EPI Data Center Specialist curriculum, the optimal placement for temperature and humidity sensors is at the intake of the equipment in the cold aisle, as it directly correlates to the environmental conditions affecting the servers. This positioning allows for a more effective audit of cooling performance, which is critical for maintaining the reliability and efficiency of the data center’s operations.
C
Explanation:
For a cooling audit in a data center, it is essential to measure temperature and humidity where air enters the servers to accurately assess cooling performance. In this case, since all servers have a front-to-rear (F-R) airflow design, measuring at the front/intake of the server will provide a precise understanding of the cooling conditions that the equipment is experiencing .
Detailed Explanation
Servers with a front-to-rear airflow design draw in cool air from the cold aisle at the front, which is then exhausted into the hot aisle at the rear. By measuring temperature and humidity 50 mm/2 inches from the front intake, you gather data on the air conditions right before it enters the servers, providing an accurate representation of the cooling environment as it directly impacts the equipment.
Measuring in the cold aisle at the front intake ensures that the readings reflect the actual conditions of the incoming air that the servers depend on for effective cooling. This approach is consistent with best practices for maintaining thermal conditions in a data center, as it helps confirm that the cooling systems are delivering air within the required temperature and humidity specifications.
EPI Data Center Specialist References:
According to the EPI Data Center Specialist curriculum, the optimal placement for temperature and humidity sensors is at the intake of the equipment in the cold aisle, as it directly correlates to the environmental conditions affecting the servers. This positioning allows for a more effective audit of cooling performance, which is critical for maintaining the reliability and efficiency of the data center’s operations.
Question #4
You are installing new copper cabling.
What is the advantage or disadvantage of choosing pre-terminated category 6 or 6A cabling?
- A . Pre-terminated cabling is already factory tested and saves installation time.
- B . There is no advantage as most new copper cabling network designs are based on category 3 or 5E for horizontal cabling.
- C . Pre-terminated cabling has a higher fire rating.
- D . Pre-terminated cabling makes ordering of the copper cables more complex, as you need to know in advance on which side the male or female connector needs to be located.
Correct Answer: A
A
Explanation:
Choosing pre-terminated category 6 or 6A cabling provides several advantages, primarily related to time savings and reliability. Since pre-terminated cables are factory tested, they ensure consistent quality and performance, reducing the need for additional testing during installation. This makes installation faster and more efficient, which can significantly reduce labor costs and deployment times.
Detailed Explanation
Pre-terminated cabling systems are manufactured and tested in controlled environments, which ensures they meet industry standards for performance. This factory testing process minimizes the likelihood of faults, reducing the need for troubleshooting and retesting on-site. Moreover, pre-terminated solutions can help to streamline installations because they eliminate the need for on-site terminations, which can be time-consuming and require skilled labor.
This is especially beneficial for data centers, where rapid deployment and minimizing potential points of failure are critical to maintaining uptime. However, it is important to note that pre-terminated cables require accurate planning, as lengths and connector configurations must be predetermined.
EPI Data Center Specialist References:
According to EPI Data Center Specialist guidelines, pre-terminated cabling is advantageous in data center environments due to reduced installation time and enhanced reliability from factory testing. These attributes align with best practices for efficient data center management, where maintaining performance and minimizing downtime are priorities.
A
Explanation:
Choosing pre-terminated category 6 or 6A cabling provides several advantages, primarily related to time savings and reliability. Since pre-terminated cables are factory tested, they ensure consistent quality and performance, reducing the need for additional testing during installation. This makes installation faster and more efficient, which can significantly reduce labor costs and deployment times.
Detailed Explanation
Pre-terminated cabling systems are manufactured and tested in controlled environments, which ensures they meet industry standards for performance. This factory testing process minimizes the likelihood of faults, reducing the need for troubleshooting and retesting on-site. Moreover, pre-terminated solutions can help to streamline installations because they eliminate the need for on-site terminations, which can be time-consuming and require skilled labor.
This is especially beneficial for data centers, where rapid deployment and minimizing potential points of failure are critical to maintaining uptime. However, it is important to note that pre-terminated cables require accurate planning, as lengths and connector configurations must be predetermined.
EPI Data Center Specialist References:
According to EPI Data Center Specialist guidelines, pre-terminated cabling is advantageous in data center environments due to reduced installation time and enhanced reliability from factory testing. These attributes align with best practices for efficient data center management, where maintaining performance and minimizing downtime are priorities.
Question #5
When are the wet bulb and dry bulb temperatures identical?
- A . When the dry bulb’s temperature is at the lowest allowable temperature for IT equipment as per ASHRAE
- B . When the dry bulb’s temperature is at the highest allowable temperature for IT equipment as per ASHRAE
- C . When the relative humidity is at the best practice value for relative humidity, being 50% RH
- D . When the relative humidity is 100%
Correct Answer: D
D
Explanation:
The wet bulb and dry bulb temperatures become identical when the relative humidity reaches 100%.
At this point, the air is fully saturated with moisture, meaning it can no longer absorb additional water vapor. As a result, the rate of evaporation decreases, and there is no difference between the dry bulb and wet bulb temperatures.
Detailed Explanation
The dry bulb temperature measures the air temperature, while the wet bulb temperature takes into account the cooling effect of evaporation. When relative humidity is at 100%, the air has reached its saturation point, and no further evaporation occurs. This causes both the wet bulb and dry bulb
thermometers to display the same temperature reading. This condition is critical in understanding environmental conditions, particularly in HVAC and data center environments, where humidity control is essential to avoid equipment overheating or corrosion.
EPI Data Center Specialist References:
The EPI Data Center Specialist training includes understanding humidity levels and their impact on data center environments. Knowing when wet bulb and dry bulb temperatures align helps data center operators manage moisture levels effectively, which is essential for preventing issues related to high humidity, such as condensation on IT equipment.
D
Explanation:
The wet bulb and dry bulb temperatures become identical when the relative humidity reaches 100%.
At this point, the air is fully saturated with moisture, meaning it can no longer absorb additional water vapor. As a result, the rate of evaporation decreases, and there is no difference between the dry bulb and wet bulb temperatures.
Detailed Explanation
The dry bulb temperature measures the air temperature, while the wet bulb temperature takes into account the cooling effect of evaporation. When relative humidity is at 100%, the air has reached its saturation point, and no further evaporation occurs. This causes both the wet bulb and dry bulb
thermometers to display the same temperature reading. This condition is critical in understanding environmental conditions, particularly in HVAC and data center environments, where humidity control is essential to avoid equipment overheating or corrosion.
EPI Data Center Specialist References:
The EPI Data Center Specialist training includes understanding humidity levels and their impact on data center environments. Knowing when wet bulb and dry bulb temperatures align helps data center operators manage moisture levels effectively, which is essential for preventing issues related to high humidity, such as condensation on IT equipment.
Question #6
A new network storage device in a non-standard size rack of approximately 600 kg/1,300 lbs is going to be installed in the data center.
Are new floor loading calculations required?
- A . No, as long as the equipment is less than 700 kg/1,500 lbs it will be within the limits.
- B . No, specifications of equipment brought into the data center will already be known during the design of the data center, and therefore the floor will be able to handle it.
- C . Yes, additional floor loading calculations need to be done by the floor manager, which should be verified by the safety engineer.
- D . Yes, a structural engineer, approved/endorsed by the building owner, should carry out new floor loading calculations.
Correct Answer: D
D
Explanation:
For heavy equipment, such as a network storage device weighing approximately 600 kg/1,300 lbs, new floor loading calculations are indeed required, particularly since the rack is non-standard. A structural engineer, approved by the building owner, should conduct these calculations to ensure the floor can safely support the new load without risking structural integrity .
Detailed Explanation
Data centers are designed with specific floor load ratings, which are determined during the design phase based on anticipated equipment. When adding or replacing equipment that is significantly heavy or non-standard, reassessing the floor’s capacity is essential to avoid overloading. A structural engineer has the expertise to verify if the existing floor can accommodate the weight and, if not, can recommend reinforcement measures.
This step ensures compliance with safety standards and helps prevent damage to the infrastructure, which could lead to costly repairs or even catastrophic failure in extreme cases.
EPI Data Center Specialist References:
EPI Data Center Specialist training advises that any changes in the data center load, particularly involving non-standard and heavy equipment, warrant a structural assessment. Ensuring compliance with floor load capacity is a critical safety and operational concern, as underscoring data center infrastructure reliability and safety is a priority in EPI’s best practices.
D
Explanation:
For heavy equipment, such as a network storage device weighing approximately 600 kg/1,300 lbs, new floor loading calculations are indeed required, particularly since the rack is non-standard. A structural engineer, approved by the building owner, should conduct these calculations to ensure the floor can safely support the new load without risking structural integrity .
Detailed Explanation
Data centers are designed with specific floor load ratings, which are determined during the design phase based on anticipated equipment. When adding or replacing equipment that is significantly heavy or non-standard, reassessing the floor’s capacity is essential to avoid overloading. A structural engineer has the expertise to verify if the existing floor can accommodate the weight and, if not, can recommend reinforcement measures.
This step ensures compliance with safety standards and helps prevent damage to the infrastructure, which could lead to costly repairs or even catastrophic failure in extreme cases.
EPI Data Center Specialist References:
EPI Data Center Specialist training advises that any changes in the data center load, particularly involving non-standard and heavy equipment, warrant a structural assessment. Ensuring compliance with floor load capacity is a critical safety and operational concern, as underscoring data center infrastructure reliability and safety is a priority in EPI’s best practices.
Question #7
A data center has its own power supply from the public utility and receives chilled water supply from
the building owner.
What needs to be taken into consideration when calculating the PUE?
- A . Nothing, as the chiller plant in the building also uses electrical power
- B . You will need to take the value for COP of the chiller plant into consideration
- C . You will need to take a weight factor of 0.4 for district chilled water into consideration
- D . PUE calculations are not possible in shared buildings
Correct Answer: C
C
Explanation:
When calculating Power Usage Effectiveness (PUE) in a data center that uses chilled water from an external source, like from a building owner, a weight factor for district chilled water must be applied. This is because PUE calculations aim to measure the energy efficiency of the data center’s own operations, and external utilities like district chilled water aren’t directly powered by the data center. A weight factor of 0.4 is typically used to account for the energy consumed to produce and deliver the chilled water, reflecting the indirect impact on the data center’s total energy consumption .
Detailed Explanation
PUE is calculated as the ratio of the total facility energy to the IT equipment energy. If the cooling is provided by an external chilled water source, it’s necessary to adjust the calculations to accurately reflect the energy impact. By incorporating the 0.4 weight factor, data centers can calculate a more accurate PUE, aligning with standard methods and industry best practices.
EPI Data Center Specialist References:
EPI training on PUE highlights the importance of adjusting for external energy sources, such as district cooling, in the calculations. This ensures that PUE values remain accurate and comparable across different data centers, even when external utilities are used.
C
Explanation:
When calculating Power Usage Effectiveness (PUE) in a data center that uses chilled water from an external source, like from a building owner, a weight factor for district chilled water must be applied. This is because PUE calculations aim to measure the energy efficiency of the data center’s own operations, and external utilities like district chilled water aren’t directly powered by the data center. A weight factor of 0.4 is typically used to account for the energy consumed to produce and deliver the chilled water, reflecting the indirect impact on the data center’s total energy consumption .
Detailed Explanation
PUE is calculated as the ratio of the total facility energy to the IT equipment energy. If the cooling is provided by an external chilled water source, it’s necessary to adjust the calculations to accurately reflect the energy impact. By incorporating the 0.4 weight factor, data centers can calculate a more accurate PUE, aligning with standard methods and industry best practices.
EPI Data Center Specialist References:
EPI training on PUE highlights the importance of adjusting for external energy sources, such as district cooling, in the calculations. This ensures that PUE values remain accurate and comparable across different data centers, even when external utilities are used.
Question #8
What is the main reason to install Earth Leakage protection?
- A . Protection of ICT equipment against high-frequency noise currents
- B . Protection of human lives
- C . Improvement of the data center grounding/earthing system
- D . Protection against lightning strikes
Correct Answer: B
B
Explanation:
Earth Leakage Protection is primarily installed to protect human lives by detecting and disconnecting power when a fault current flows to the ground. This type of protection is essential to avoid electrical shock hazards that could occur when insulation fails, or equipment is improperly grounded .
Detailed Explanation
Earth leakage currents can occur due to insulation faults or accidental contact with live parts. Earth Leakage Protection systems, such as Residual Current Devices (RCDs), quickly detect these faults and disconnect the circuit to prevent harm to personnel. This is especially crucial in environments like data centers where high-powered equipment is continuously running and any electrical fault can pose significant safety risks.
EPI Data Center Specialist References:
EPI emphasizes that human safety is paramount in data center operations. Proper grounding and leakage protection are fundamental safety measures, and EPI guidelines align with this focus, underscoring the importance of protecting personnel from electrical hazards through appropriate safety systems.
B
Explanation:
Earth Leakage Protection is primarily installed to protect human lives by detecting and disconnecting power when a fault current flows to the ground. This type of protection is essential to avoid electrical shock hazards that could occur when insulation fails, or equipment is improperly grounded .
Detailed Explanation
Earth leakage currents can occur due to insulation faults or accidental contact with live parts. Earth Leakage Protection systems, such as Residual Current Devices (RCDs), quickly detect these faults and disconnect the circuit to prevent harm to personnel. This is especially crucial in environments like data centers where high-powered equipment is continuously running and any electrical fault can pose significant safety risks.
EPI Data Center Specialist References:
EPI emphasizes that human safety is paramount in data center operations. Proper grounding and leakage protection are fundamental safety measures, and EPI guidelines align with this focus, underscoring the importance of protecting personnel from electrical hazards through appropriate safety systems.
Question #9
The noise levels in the data center are approximately 91 dB (A).
Do employers need to take precautions?
- A . No, anything less than 100 dB (A) is acceptable.
- B . There are no regulations regarding noise levels inside a building. Regulations only apply to noise pollution outside of the building.
- C . As long as the data is compliant to ISO/IEC 27001 it is acceptable.
- D . Yes, since it is mandated by regulations.
Correct Answer: D
D
Explanation:
In a data center with noise levels of 91 dB (A), employers are indeed required to take precautions to protect personnel, as this level exceeds commonly accepted safety thresholds for occupational noise exposure. Regulations, such as those from the Occupational Safety and Health Administration (OSHA) or similar agencies, mandate specific controls and protections for environments with high noise levels.
Detailed Explanation
Noise levels above 85 dB (A) typically trigger requirements for hearing conservation programs. At 91 dB (A), steps like providing ear protection, conducting regular noise assessments, and possibly implementing engineering controls to reduce noise should be taken. Extended exposure to such levels can lead to hearing loss, so regulatory compliance ensures both immediate and long-term protection for personnel.
EPI Data Center Specialist References:
EPI guidelines for data center safety address noise exposure as part of the environmental safety measures. EPI recommends adhering to local occupational health regulations, as excessive noise can harm personnel and affect operational efficiency due to potential health hazards.
D
Explanation:
In a data center with noise levels of 91 dB (A), employers are indeed required to take precautions to protect personnel, as this level exceeds commonly accepted safety thresholds for occupational noise exposure. Regulations, such as those from the Occupational Safety and Health Administration (OSHA) or similar agencies, mandate specific controls and protections for environments with high noise levels.
Detailed Explanation
Noise levels above 85 dB (A) typically trigger requirements for hearing conservation programs. At 91 dB (A), steps like providing ear protection, conducting regular noise assessments, and possibly implementing engineering controls to reduce noise should be taken. Extended exposure to such levels can lead to hearing loss, so regulatory compliance ensures both immediate and long-term protection for personnel.
EPI Data Center Specialist References:
EPI guidelines for data center safety address noise exposure as part of the environmental safety measures. EPI recommends adhering to local occupational health regulations, as excessive noise can harm personnel and affect operational efficiency due to potential health hazards.
Question #10
The UPS of a data center, with an ANSI/TIA-942 Rating-4, is installed with the rectifier connected to power feed A and the bypass/reserve line input connected to power feed
B. To which feed will the output of the UPS be synchronized?
- A . The UPS will not synchronize to any of the feeds but use an internal clock to set the output voltage and frequency
- B . Depends on the setting of the UPS, as the UPS can normally be set to either feed
- C . Feed A
- D . Feed B
Correct Answer: B
B
Explanation:
For a UPS system in a Rating-4 data center, the synchronization of output can indeed depend on the specific settings of the UPS. Generally, such systems allow for flexible configuration where the output can be synchronized to either power feed A or B, depending on which feed is preferred for stability or redundancy purposes.
Detailed Explanation
In dual-feed setups, such as those in high-redundancy data centers, the UPS can be set to synchronize with either feed. This ensures that the UPS maintains continuity in case one feed becomes unstable or fails. The flexibility to choose synchronization to either feed enhances the resiliency and reliability of power supply, which is critical in Tier IV (Rating-4) facilities where uptime is paramount.
EPI Data Center Specialist References:
The EPI Data Center Specialist course underscores the importance of configurable UPS systems in Rating-4 data centers, where redundancy and continuous power are critical. By allowing synchronization to either feed, the UPS can maintain the highest level of reliability, which aligns with the rigorous standards expected in such environments.
B
Explanation:
For a UPS system in a Rating-4 data center, the synchronization of output can indeed depend on the specific settings of the UPS. Generally, such systems allow for flexible configuration where the output can be synchronized to either power feed A or B, depending on which feed is preferred for stability or redundancy purposes.
Detailed Explanation
In dual-feed setups, such as those in high-redundancy data centers, the UPS can be set to synchronize with either feed. This ensures that the UPS maintains continuity in case one feed becomes unstable or fails. The flexibility to choose synchronization to either feed enhances the resiliency and reliability of power supply, which is critical in Tier IV (Rating-4) facilities where uptime is paramount.
EPI Data Center Specialist References:
The EPI Data Center Specialist course underscores the importance of configurable UPS systems in Rating-4 data centers, where redundancy and continuous power are critical. By allowing synchronization to either feed, the UPS can maintain the highest level of reliability, which aligns with the rigorous standards expected in such environments.
Question #11
What is a potential disadvantage of using a hypoxic-based fire suppression system as a fire extinguishing system?
- A . It can only be used in computer rooms which have sufficient air changes per hour.
- B . The gas containers need to be close to the hazard area.
- C . It can only be used in non-continuous occupied areas.
- D . It can only be used in computer rooms where you have sufficient positive pressure.
Correct Answer: C
C
Explanation:
A hypoxic-based fire suppression system works by reducing the oxygen level in a room to below what is necessary to sustain combustion. This makes it effective in fire prevention, but it is not suitable for continuous occupancy by personnel. Low oxygen levels can cause discomfort or even health risks for people spending extended periods in the space. Therefore, these systems are typically deployed in areas where continuous human occupancy is not required, such as storage rooms or data halls with limited personnel access.
Detailed Explanation
Hypoxic fire suppression systems lower oxygen levels to around 15-16%, which is safe for short periods but not sustainable for continuous occupancy without risk to health. Data center environments where staff need to spend long periods monitoring and maintaining equipment would need alternative systems, like gas-based suppression that allows for safe evacuation rather than oxygen reduction.
EPI Data Center Specialist References:
The EPI Data Center Specialist curriculum emphasizes that fire suppression systems must be chosen based on occupancy requirements. Hypoxic systems are specifically noted as unsuitable for spaces requiring continuous human presence due to the low oxygen environment they create.
C
Explanation:
A hypoxic-based fire suppression system works by reducing the oxygen level in a room to below what is necessary to sustain combustion. This makes it effective in fire prevention, but it is not suitable for continuous occupancy by personnel. Low oxygen levels can cause discomfort or even health risks for people spending extended periods in the space. Therefore, these systems are typically deployed in areas where continuous human occupancy is not required, such as storage rooms or data halls with limited personnel access.
Detailed Explanation
Hypoxic fire suppression systems lower oxygen levels to around 15-16%, which is safe for short periods but not sustainable for continuous occupancy without risk to health. Data center environments where staff need to spend long periods monitoring and maintaining equipment would need alternative systems, like gas-based suppression that allows for safe evacuation rather than oxygen reduction.
EPI Data Center Specialist References:
The EPI Data Center Specialist curriculum emphasizes that fire suppression systems must be chosen based on occupancy requirements. Hypoxic systems are specifically noted as unsuitable for spaces requiring continuous human presence due to the low oxygen environment they create.
Question #12
The humidity in the computer room has changed from about 50% down to 35% Relative Humidity (RH).
What influence does this have on Electrostatic Discharge (ESD)?
- A . No influence as long as the temperature is at approximately 20°C/77°F
- B . Relative humidity has no influence on ESD
- C . ESD levels will go up
- D . ESD levels will go down
Correct Answer: C
C
Explanation:
As relative humidity decreases, Electrostatic Discharge (ESD) risks increase. Lower humidity levels reduce the amount of moisture in the air, which normally helps dissipate static charges. When the humidity drops from 50% to 35%, the likelihood of static electricity accumulating on surfaces rises, leading to a higher potential for ESD incidents that could damage sensitive IT equipment .
Detailed Explanation
ESD events are more common in dry environments because there is less atmospheric moisture to neutralize electrical charges. Maintaining relative humidity above 40% helps minimize the risk of ESD, which is why data centers often control humidity levels tightly to protect equipment from static discharge that could cause hardware failures or data loss.
EPI Data Center Specialist References:
EPI data center best practices stress the importance of maintaining stable humidity levels to prevent ESD, particularly in computer rooms. Recommended humidity ranges are typically above 40% to prevent conditions that would foster static buildup.
C
Explanation:
As relative humidity decreases, Electrostatic Discharge (ESD) risks increase. Lower humidity levels reduce the amount of moisture in the air, which normally helps dissipate static charges. When the humidity drops from 50% to 35%, the likelihood of static electricity accumulating on surfaces rises, leading to a higher potential for ESD incidents that could damage sensitive IT equipment .
Detailed Explanation
ESD events are more common in dry environments because there is less atmospheric moisture to neutralize electrical charges. Maintaining relative humidity above 40% helps minimize the risk of ESD, which is why data centers often control humidity levels tightly to protect equipment from static discharge that could cause hardware failures or data loss.
EPI Data Center Specialist References:
EPI data center best practices stress the importance of maintaining stable humidity levels to prevent ESD, particularly in computer rooms. Recommended humidity ranges are typically above 40% to prevent conditions that would foster static buildup.
Question #13
A computer room with a raised floor has been designed with racks in a hot/cold aisle setup.
What should you recommend for the placement of down-flow air conditioners?
- A . Air conditioners perpendicular to (at the end of the row of) the Cold-Aisle
- B . Air conditioners perpendicular to (at the end of the row of) the Hot-Aisle
- C . Air conditioners should always be placed at both sides of each row of racks
- D . Air conditioner placement has no influence on cooling effectiveness and efficiency. Hence, they can be placed at any convenient location.
Correct Answer: A
A
Explanation:
In a hot/cold aisle configuration, placing down-flow air conditioners perpendicular to the cold aisle ensures that cool air is directed efficiently into the cold aisles where server intakes are located. This layout allows for optimal cooling performance by aligning the airflow directly with the equipment intakes, minimizing hot spots and enhancing cooling efficiency .
Detailed Explanation
With a raised floor design, cold air from the air conditioners is supplied into the cold aisle, where server intakes are located. Positioning the air conditioning units perpendicular to the cold aisles ensures that cool air is delivered directly into these aisles, preventing air mixing and optimizing cooling. This setup takes full advantage of the airflow management strategy inherent to the hot/cold aisle configuration.
EPI Data Center Specialist References:
EPI guidelines on cooling emphasize that down-flow air conditioners should be positioned to maximize the effectiveness of cold aisle delivery, which improves cooling efficiency and helps maintain consistent temperatures across server racks.
A
Explanation:
In a hot/cold aisle configuration, placing down-flow air conditioners perpendicular to the cold aisle ensures that cool air is directed efficiently into the cold aisles where server intakes are located. This layout allows for optimal cooling performance by aligning the airflow directly with the equipment intakes, minimizing hot spots and enhancing cooling efficiency .
Detailed Explanation
With a raised floor design, cold air from the air conditioners is supplied into the cold aisle, where server intakes are located. Positioning the air conditioning units perpendicular to the cold aisles ensures that cool air is delivered directly into these aisles, preventing air mixing and optimizing cooling. This setup takes full advantage of the airflow management strategy inherent to the hot/cold aisle configuration.
EPI Data Center Specialist References:
EPI guidelines on cooling emphasize that down-flow air conditioners should be positioned to maximize the effectiveness of cold aisle delivery, which improves cooling efficiency and helps maintain consistent temperatures across server racks.
Question #14
A computer room needs to be fitted out with a gas-based fire suppression system. The computer room will be a high-density data center with about 30% of the racks being closed circuit cooling blade-center racks.
Should the supplier of the fire suppression system be informed on the design of the racks?
- A . No, cooling and design of racks have no influence on the fire suppression system design.
- B . Only when the rack height obstructs a potential fire suppression release point.
- C . Yes, the design of the racks has an influence on the fire suppression system design.
- D . Only when the racks might block access to the fire panel.
Correct Answer: C
C
Explanation:
The design and configuration of racks, particularly high-density and closed-circuit cooling racks, directly impact the fire suppression system design. Closed-circuit cooling racks, like blade-center racks, can affect airflow and potentially trap heat, influencing how fire suppression agents are distributed within the space. Therefore, it is essential to inform the fire suppression system supplier about the rack design to ensure effective coverage and proper agent distribution .
Detailed Explanation
High-density racks can change how smoke and heat travel, which in turn affects fire detection and suppression. Closed racks with built-in cooling can isolate airflow, requiring adjustments in fire suppression design to ensure that suppression agents reach all necessary areas, including within enclosed spaces. The supplier may need to account for these factors to ensure proper protection coverage.
EPI Data Center Specialist References:
The EPI Data Center Specialist training underscores that fire suppression systems must be tailored to the specific environmental characteristics of the data center. The design of racks, particularly high-density configurations, should always be considered to ensure that suppression agents can effectively control a fire, even in contained rack spaces.
C
Explanation:
The design and configuration of racks, particularly high-density and closed-circuit cooling racks, directly impact the fire suppression system design. Closed-circuit cooling racks, like blade-center racks, can affect airflow and potentially trap heat, influencing how fire suppression agents are distributed within the space. Therefore, it is essential to inform the fire suppression system supplier about the rack design to ensure effective coverage and proper agent distribution .
Detailed Explanation
High-density racks can change how smoke and heat travel, which in turn affects fire detection and suppression. Closed racks with built-in cooling can isolate airflow, requiring adjustments in fire suppression design to ensure that suppression agents reach all necessary areas, including within enclosed spaces. The supplier may need to account for these factors to ensure proper protection coverage.
EPI Data Center Specialist References:
The EPI Data Center Specialist training underscores that fire suppression systems must be tailored to the specific environmental characteristics of the data center. The design of racks, particularly high-density configurations, should always be considered to ensure that suppression agents can effectively control a fire, even in contained rack spaces.
Question #15
The ‘maximum exposed area’ of the fire-rated glass is defined by the supplier as 3 sqm/32 sqft. The window area is 4 sqm/43 sqft.
What would be the best option?
- A . Do not use fire-rated glass due to the size limit and replace it with normal glass.
- B . Split the window in two equal parts using an aluminum frame.
- C . Split the window into parts smaller than specified as the maximum exposed area and ensure fire-rated frames are used.
- D . Split the window in two equal parts fitted together with transparent silicon glue.
Correct Answer: C
C
Explanation:
When the window area exceeds the maximum exposed area specified for fire-rated glass, it is necessary to split the window into sections that comply with the fire rating requirements. This means creating smaller sections that are each within the 3 sqm/32 sqft limit and using fire-rated frames to ensure that the entire assembly meets fire safety standards. This approach maintains the fire-rated integrity of the glass, while allowing for larger window areas .
Detailed Explanation
Fire-rated glass is designed to contain fire and prevent it from spreading. If the window exceeds the maximum exposed area defined by the supplier, the integrity of the fire-rated glass could be compromised. By dividing the window into compliant sections with fire-rated frames, you ensure that each pane performs as intended in the event of a fire. Fire-rated frames help maintain the fire resistance across the entire assembly, making this option the best for safety and compliance.
EPI Data Center Specialist References:
EPI recommends adhering strictly to fire safety standards, especially when using materials like fire-rated glass. The guidelines emphasize that modifications should always respect the manufacturer’s specifications to ensure the system remains effective in containing and preventing the spread of fire.
C
Explanation:
When the window area exceeds the maximum exposed area specified for fire-rated glass, it is necessary to split the window into sections that comply with the fire rating requirements. This means creating smaller sections that are each within the 3 sqm/32 sqft limit and using fire-rated frames to ensure that the entire assembly meets fire safety standards. This approach maintains the fire-rated integrity of the glass, while allowing for larger window areas .
Detailed Explanation
Fire-rated glass is designed to contain fire and prevent it from spreading. If the window exceeds the maximum exposed area defined by the supplier, the integrity of the fire-rated glass could be compromised. By dividing the window into compliant sections with fire-rated frames, you ensure that each pane performs as intended in the event of a fire. Fire-rated frames help maintain the fire resistance across the entire assembly, making this option the best for safety and compliance.
EPI Data Center Specialist References:
EPI recommends adhering strictly to fire safety standards, especially when using materials like fire-rated glass. The guidelines emphasize that modifications should always respect the manufacturer’s specifications to ensure the system remains effective in containing and preventing the spread of fire.
Question #16
A data center scores Rated-3 in mechanical, Rated-4 in electrical, and Rated-2 in architectural.
What is the overall Rating of this data center when the Rating is based on the ANSI/TIA-942?
- A . Rated-2 since that is the lowest rating received
- B . Rated-4 since that is the highest rating received
- C . Rated-4 since electrical is more important than mechanical and architectural
- D . Depends on the Rating scored in telecommunications
Correct Answer: A
A
Explanation:
According to ANSI/TIA-942 standards, the overall data center rating is determined by the lowest rating among all evaluated categories. Therefore, if a data center is rated 2 in architectural, despite being rated higher in mechanical and electrical, the overall rating is Rated-2. This approach ensures that all aspects meet a minimum standard and prevents a higher rating if any critical area does not comply.
Detailed Explanation
ANSI/TIA-942 evaluates data centers across several areas, including mechanical, electrical, architectural, and telecommunications. The overall rating reflects the lowest rated category, ensuring that no aspect of the data center’s design or operation falls below the specified level. Thus, in this case, the architectural rating of 2 dictates the final rating, ensuring a comprehensive and balanced assessment of reliability and resilience across all aspects.
EPI Data Center Specialist References:
EPI Data Center Specialist training aligns with ANSI/TIA-942, stating that the final rating must reflect the lowest score to ensure comprehensive reliability across all critical infrastructure categories. This avoids overstating the data center’s resilience and ensures uniform standards across areas.
A
Explanation:
According to ANSI/TIA-942 standards, the overall data center rating is determined by the lowest rating among all evaluated categories. Therefore, if a data center is rated 2 in architectural, despite being rated higher in mechanical and electrical, the overall rating is Rated-2. This approach ensures that all aspects meet a minimum standard and prevents a higher rating if any critical area does not comply.
Detailed Explanation
ANSI/TIA-942 evaluates data centers across several areas, including mechanical, electrical, architectural, and telecommunications. The overall rating reflects the lowest rated category, ensuring that no aspect of the data center’s design or operation falls below the specified level. Thus, in this case, the architectural rating of 2 dictates the final rating, ensuring a comprehensive and balanced assessment of reliability and resilience across all aspects.
EPI Data Center Specialist References:
EPI Data Center Specialist training aligns with ANSI/TIA-942, stating that the final rating must reflect the lowest score to ensure comprehensive reliability across all critical infrastructure categories. This avoids overstating the data center’s resilience and ensures uniform standards across areas.
Question #17
The data center has been in operation for about 1 year and 2 months. The dust levels in the computer room are relatively high.
What is the most likely root cause?
- A . The cleaning crew is not doing their work properly
- B . Every computer room has high dust levels due to constant high-speed air movement
- C . Low pressure in the computer room
- D . Floorboards are most likely not fitted correctly
Correct Answer: D
D
Explanation:
High dust levels in a computer room are often due to improperly fitted floorboards. When floorboards are not securely installed or do not fit tightly, they allow dust and particles from the subfloor to enter the room. In a data center, this can lead to high levels of dust that affect air quality and equipment performance.
Detailed Explanation
Raised floors in data centers can accumulate dust and debris, especially if the floorboards are not properly sealed. Loose or improperly fitted floorboards allow contaminants from the subfloor to enter the data center environment, increasing the dust levels over time. Proper installation and maintenance of floor panels are essential to prevent dust infiltration and maintain clean conditions.
EPI Data Center Specialist References:
EPI training emphasizes proper flooring installation and maintenance to control air quality within data centers. Correctly fitted floorboards prevent dust accumulation from the subfloor, which helps protect sensitive equipment and maintains a cleaner environment.
D
Explanation:
High dust levels in a computer room are often due to improperly fitted floorboards. When floorboards are not securely installed or do not fit tightly, they allow dust and particles from the subfloor to enter the room. In a data center, this can lead to high levels of dust that affect air quality and equipment performance.
Detailed Explanation
Raised floors in data centers can accumulate dust and debris, especially if the floorboards are not properly sealed. Loose or improperly fitted floorboards allow contaminants from the subfloor to enter the data center environment, increasing the dust levels over time. Proper installation and maintenance of floor panels are essential to prevent dust infiltration and maintain clean conditions.
EPI Data Center Specialist References:
EPI training emphasizes proper flooring installation and maintenance to control air quality within data centers. Correctly fitted floorboards prevent dust accumulation from the subfloor, which helps protect sensitive equipment and maintains a cleaner environment.
Question #18
You have three UPS systems connected in parallel. The UPS systems have an imbalance in the load sharing of approximately 20%.
What should you recommend?
- A . Review the cable lengths of each UPS to the common busbar
- B . Nothing, there is no reason for any concern
- C . Review the common mode noise levels within the computer room
- D . Review the harmonics levels within the computer room
Correct Answer: A
A
Explanation:
An imbalance in load sharing between UPS systems connected in parallel can often result from unequal cable lengths to the common busbar. If the cabling from each UPS to the busbar varies significantly in length, it can lead to differences in impedance, resulting in uneven load distribution. Ensuring that cable lengths are consistent helps to balance the load sharing across the UPS systems .
Detailed Explanation
Parallel UPS systems rely on uniform impedance to share loads evenly. Differences in cable lengths cause variations in resistance, leading to one or more UPS units carrying a disproportionate share of the load. Standardizing cable lengths ensures equal impedance, which promotes balanced load sharing and prevents one UPS from being overburdened, thus maintaining overall system reliability.
EPI Data Center Specialist References:
EPI guidelines recommend checking cable lengths when load imbalances occur in parallel UPS configurations. Ensuring equal lengths is a common method to resolve impedance issues that affect load distribution, which is critical for the stable operation of redundant power systems.
A
Explanation:
An imbalance in load sharing between UPS systems connected in parallel can often result from unequal cable lengths to the common busbar. If the cabling from each UPS to the busbar varies significantly in length, it can lead to differences in impedance, resulting in uneven load distribution. Ensuring that cable lengths are consistent helps to balance the load sharing across the UPS systems .
Detailed Explanation
Parallel UPS systems rely on uniform impedance to share loads evenly. Differences in cable lengths cause variations in resistance, leading to one or more UPS units carrying a disproportionate share of the load. Standardizing cable lengths ensures equal impedance, which promotes balanced load sharing and prevents one UPS from being overburdened, thus maintaining overall system reliability.
EPI Data Center Specialist References:
EPI guidelines recommend checking cable lengths when load imbalances occur in parallel UPS configurations. Ensuring equal lengths is a common method to resolve impedance issues that affect load distribution, which is critical for the stable operation of redundant power systems.
Question #19
You are working on the design of a new facility. The electrical riser of the building with high current power is located close to the area where sensitive IT equipment in the computer room will be located.
What should you recommend to reduce the amount of EMF coming from the electrical riser?
- A . Install single-phase power cabling
- B . Install three-phase power cabling based on three individual core wires
- C . Install bus bar trunking
- D . Install three-phase power cabling based on a combined cable (e.g. XLPE etc.)
Correct Answer: D
D
Explanation:
To reduce Electromagnetic Fields (EMF) emanating from the electrical riser near sensitive IT equipment, three-phase power cabling in a combined cable (such as XLPE) is effective. Combined cabling helps reduce EMF by keeping the conductors tightly packed, which minimizes magnetic fields generated by current flow. Cables like XLPE (cross-linked polyethylene) also offer better insulation, which helps mitigate EMF interference with nearby IT equipment .
Detailed Explanation
Using a combined three-phase cable reduces EMF because the magnetic fields generated by each phase tend to cancel each other out when in close proximity. This arrangement helps reduce the overall magnetic field strength. In addition, XLPE and similar materials provide good insulation, making them a preferred choice for reducing EMF emissions around sensitive equipment.
EPI Data Center Specialist References:
EPI data center best practices recommend mitigating EMF interference through combined cabling arrangements, especially near areas where sensitive IT equipment is located. Reducing EMF is crucial to maintaining equipment reliability and ensuring compliance with safety standards.
D
Explanation:
To reduce Electromagnetic Fields (EMF) emanating from the electrical riser near sensitive IT equipment, three-phase power cabling in a combined cable (such as XLPE) is effective. Combined cabling helps reduce EMF by keeping the conductors tightly packed, which minimizes magnetic fields generated by current flow. Cables like XLPE (cross-linked polyethylene) also offer better insulation, which helps mitigate EMF interference with nearby IT equipment .
Detailed Explanation
Using a combined three-phase cable reduces EMF because the magnetic fields generated by each phase tend to cancel each other out when in close proximity. This arrangement helps reduce the overall magnetic field strength. In addition, XLPE and similar materials provide good insulation, making them a preferred choice for reducing EMF emissions around sensitive equipment.
EPI Data Center Specialist References:
EPI data center best practices recommend mitigating EMF interference through combined cabling arrangements, especially near areas where sensitive IT equipment is located. Reducing EMF is crucial to maintaining equipment reliability and ensuring compliance with safety standards.
Question #20
The location of a data center is just above the Arctic Circle (North Pole). The outside air temperature is never above 21°C/70°F.
Taking energy efficiency as the highest priority, which cooling system should you recommend?
- A . Standard air conditioning units, as spares might not be readily available
- B . Any cooling system can be efficient because the outside air temperature will not influence the temperature of the air intake of the ICT equipment
- C . Waterside economizer
- D . Airside economizer
Correct Answer: D
D
Explanation:
In locations with consistently cold temperatures, such as above the Arctic Circle, an airside economizer is the most energy-efficient cooling solution. Airside economizers use cool outside air to lower indoor temperatures, reducing or even eliminating the need for mechanical cooling. Given the consistently low temperatures, this method maximizes energy efficiency by leveraging natural cooling.
Detailed Explanation
Airside economizers are ideal in environments where outside temperatures are consistently low. By drawing in and filtering cold outdoor air, they directly cool the indoor environment, thereby reducing energy consumption significantly compared to traditional air conditioning. This cooling approach aligns with energy efficiency goals by minimizing mechanical cooling demands.
EPI Data Center Specialist References:
EPI recommends the use of airside economizers in cold climates to achieve high energy efficiency, as they allow data centers to capitalize on ambient conditions for cooling, aligning with sustainability and cost-saving practices.
D
Explanation:
In locations with consistently cold temperatures, such as above the Arctic Circle, an airside economizer is the most energy-efficient cooling solution. Airside economizers use cool outside air to lower indoor temperatures, reducing or even eliminating the need for mechanical cooling. Given the consistently low temperatures, this method maximizes energy efficiency by leveraging natural cooling.
Detailed Explanation
Airside economizers are ideal in environments where outside temperatures are consistently low. By drawing in and filtering cold outdoor air, they directly cool the indoor environment, thereby reducing energy consumption significantly compared to traditional air conditioning. This cooling approach aligns with energy efficiency goals by minimizing mechanical cooling demands.
EPI Data Center Specialist References:
EPI recommends the use of airside economizers in cold climates to achieve high energy efficiency, as they allow data centers to capitalize on ambient conditions for cooling, aligning with sustainability and cost-saving practices.