CDCS EXIN EPI Certified Data Centre Specialist Question and Answers

A2(N+1) configurationimpliestwo independent UPS systems, each withN+1 redundancy. This configuration provides high availability by ensuring that each UPS system can independently support the load with an additional unit for redundancy. Given the80 kW load, this setup impliesthat two separate N+1 systems are running, providing reliability and fault tolerance for the data center’s power needs.

Detailed Explanation:

TheN+1notation denotes that each system has one additional unit beyond what is needed to carry the load, providing redundancy. With2(N+1), there are two such setups, ensuring that if one fails, the other can still support the load without interruption, fulfilling high availability requirements.

EPI Data Center Specialist References:

EPI teaches that multiple redundant systems, such as2(N+1), enhance data center reliability by ensuring that power is maintained even if a failure occurs in one system. This meets the stringent demands for uptime in critical environments.

Thebreaking capacityof afuse or breakerindicates themaximum currentit can safely interrupt without being damaged or creating a dangerous arc. This value is crucial for ensuring that the device can handle fault conditions and prevent equipment damage or fire risks due to excessive current flow.

Detailed Explanation:

The breaking capacity, also known as the interrupting rating, ensures that the fuse or breaker can safely handle fault currents up to a specified limit. Exceeding this capacity could result in the device failing to interrupt the current, potentially causing hazardous conditions like electrical arcs.

EPI Data Center Specialist References:

EPI training underscores the importance of matching fuses and breakers with appropriate breaking capacities for the anticipated fault levels in data centers to ensure reliable and safe operation.

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.

Bullet (ballistics) protectionis typically considered only for data centers that arepotential targetsor located near such targets. While ANSI/TIA-942 does not specifically require bulletproofing for all data centers, it is prudent to consider it based onlocation risk assessments, especially if the facility is in a high-risk area or near critical infrastructure that could attract threats.

Detailed Explanation:

Protective measures like bulletproofing depend on the threat landscape and the data center’s exposure to risks such as crime or terrorism. Assessments for physical security are typically customized based on location-specific risks rather than being universally required by data center standards.

EPI Data Center Specialist References:

EPI guidelines emphasize customizing physical security measures based on threat assessments, suggesting that bulletproofing is appropriate in specific circumstances where the facility’s risk profile justifies additional security measures.

To calculate thecooling airflow requirementfor ICT equipment, you can use the formula:

CFM=Power (kW)×3160ΔT(°F)\text{CFM} = \frac{\text{Power (kW)} \times 3160}{\Delta T (\text{°F})}CFM=ΔT(°F)Power (kW)×3160​

For equipment consuming6 kWwith aDelta-Tof20°F:

CFM=6×316020=948≈1,000 CFM\text{CFM} = \frac{6 \times 3160}{20} = 948 \approx 1,000 \, \text{CFM}CFM=206×3160​=948≈1,000CFM

Detailed Explanation:

This formula provides an estimate of the cubic feet per minute (CFM) of air required to cool the equipment based on its power consumption and the temperature difference (Delta-T) between intake and exhaust. The Delta-T represents the cooling effectiveness of the airflow.

EPI Data Center Specialist References:

EPI recommends using this calculation for determining airflow requirements in data centers, ensuring that cooling systems are adequately sized to maintain equipment within safe temperature limits.

A potential disadvantage of using awater mist fire suppression systemis that it canrapidly increase the humiditywithin the data center, which may pose risks tosensitive electronic equipment. Excessive humidity can lead to condensation, which could damage electronics and leadto short circuits or corrosion over time.

Detailed Explanation:

Water mist systems use fine droplets to suppress fires by cooling and displacing heat. However, the moisture generated may raise the humidity level to the point where it exceeds safe operational limits for IT equipment. Therefore, while water mist systems are effective in fire suppression, they may not be ideal in environments where high humidity could damage sensitive equipment.

EPI Data Center Specialist References:

EPI guidelines advise considering the impact of humidity from fire suppression systems, particularly in environments housing electronic equipment. It’s essential to weigh the benefits of fire suppression against potential risks to operational equipment when choosing suppression methods.

According toANSI/TIA-942 standards, the overalldata center ratingis determined by the lowest rating among all evaluated categories. Therefore, if a data center is rated2in architectural, despite being rated higher in mechanical and electrical, the overall rating isRated-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.

Blast protectionshould be considered if thedata centeror its location is apotential targetor is near high-risk areas. Blast protection measures can protect both personnel and infrastructure from potential explosion impacts, which could be essential in areas with heightened security risks.

Detailed Explanation:

In areas where there may be risks of terrorist attacks or explosions due to nearby high-risk facilities, implementing blast protection measures helps safeguard the data center's infrastructure. These measures can include reinforced walls, blast-resistant windows, and secure entryways designed to withstand explosive forces.

EPI Data Center Specialist References:

While not specifically mandated by ANSI/TIA-942, EPI training advises considering local risk factors, including proximity to potential targets, when evaluating the need for blast protection. This approach is aligned with risk assessment and mitigation practices to ensure facility security.

When calculatingPower Usage Effectiveness (PUE)in a data center that useschilled water from an external source, like from a building owner, aweight factor for district chilled watermust 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 of0.4is 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.

In ahot/cold aisle configuration, placingdown-flow air conditioners perpendicular to the cold aisleensures 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.

Anair intake temperature of 25 °C (77 °F)at thetop of the rackisacceptableaccording to data center standards and guidelines, such as those fromASHRAE. This temperature falls within the recommended range for inlet temperatures, which is typically between 18°C (64°F) and 27°C (81°F).

Detailed Explanation:

ASHRAE standards provide guidelines on acceptable temperature ranges for air intake in data centers to balance cooling efficiency and equipment safety. A temperature of 25°C is within the recommended operational range, allowing data centers to optimize energy efficiency while maintaining safe conditions for IT equipment.

EPI Data Center Specialist References:

EPI guidelines align with ASHRAE recommendations for server intake temperatures, confirming that 25°C is within acceptable limits for most mission-critical equipment. This ensures the data center maintains an efficient and reliable environment.

When installing araised floor, the best starting point is typicallyfrom the farthest corner away from the entrance, in this case,Point B. This method allows for the floor installation to progress towards the entrance, ensuring that workers can avoid walking over the newly installed tiles, thus minimizing the risk of damage and maintaining cleanliness during installation.

Detailed Explanation:

Starting at the farthest corner (Point B) and working towards the entrance (Point A) is a standard practice in raised floor installation. This approach ensures that installers do not walk over freshly laid tiles, which could lead to shifting or misalignment. Additionally, it allows for more controlledplacement and alignment, as well as convenient egress when installation is complete.

EPI Data Center Specialist References:

EPI guidelines for raised floor installation emphasize beginning at the farthest point from the entrance and working back towards it, which aligns with industry best practices for efficiency and quality assurance. This method reduces potential damage and supports precise alignment across the floor area.

When installing anautomated lighting system, especially in a security-sensitive area like a data center, it’s essential to ensure thatlighting levels support security camera functionalityat all times. Sufficient lighting is necessary for cameras to capture clear footage, ensuring continuous monitoring and security regardless of occupancy.

Detailed Explanation:

Automated lighting based on occupancy or time settings can reduce energy costs, but it must be configured to maintain adequate illumination for surveillance. Security cameras require minimum lighting levels to operate effectively, so lighting should be configured to avoid compromising security.

EPI Data Center Specialist References:

EPI emphasizes security and safety in data centers, advising that lighting systems should maintain levels conducive to effective surveillance, ensuring operational security even when lights are automatically controlled.

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.

Highdust levelsin a computer room are often due toimproperly 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 withindata centers. Correctly fitted floorboards prevent dust accumulation from the subfloor, which helps protect sensitive equipment and maintains a cleaner environment.