Exin EPI Certified Data Centre Specialist CDCS Exam Questions

Answer : B

A spirit level bar should not be used for leveling a raised floor, as measurement errors are likely to propagate from one pedestal to the next. Spirit levels can introduce cumulative errors, leading to uneven floors, particularly in large installations where precise leveling is critical.

Detailed Explanation:

Using a laser level or a precision leveling device is recommended to ensure accuracy across all floor tiles. Spirit levels, while adequate for short spans, can transfer small inaccuracies from one pedestal to another, which can cause alignment issues and floor instability over time.

EPI Data Center Specialist Reference:

EPI data center guidelines discourage the use of spirit levels for raised floors. Instead, they advocate for precision tools like laser levels that ensure consistency and accuracy in large-scale installations, aligning with best practices for raised floor construction.

Answer : D

Network administration in structured cabling is governed by ANSI/TIA-606-B, which defines requirements for cable and asset administration, labeling, documentation, and record-keeping. It specifies how pathways, spaces, and cabling should be identified and labeled to ensure proper lifecycle management.

ANSI/TIA-568 covers cabling performance standards, not administration.

ISO/IEC 30129 relates to data center facilities and infrastructure but not cable management.

ASHRAE focuses on thermal management, not cabling.

Proper administration is critical in data centers because high cable density can lead to operational issues, troubleshooting delays, and risk of downtime if poorly managed. By enforcing labeling schemes, color codes, and database-driven records, ANSI/TIA-606 supports operational excellence and compliance with ANSI/TIA-942.

Answer : C

Attenuation is the logarithmic ratio between input and output signals. For power, we use 10 log; for voltage or current, 20 log. Since EMF shielding is measured as field strength (V/m or A/m), power relationship is proportional to the square of field. Thus the correct attenuation calculation for shielding effectiveness is:

where:

M = maximum permissible field strength

R = measured field strength after shielding

This ensures the shield reduces field intensity to below allowable limits.

Answer : A

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 Reference:

According to EPI Data Center Specialist training, understanding the UPS efficiency is essential for battery sizing. Without it, the calculations could lead to either undersizing 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.

Answer : B

Inert gas systems (e.g., Inergen, Argonite, Nitrogen) extinguish fire by reducing oxygen concentration, which typically requires reducing oxygen levels to ~12--15%. This means a very large volume of gas must be discharged into the room (up to 40--50% of the protected volume). Because inert gases have a low extinguishing effectiveness by weight, more total gas is required.

Halocarbon agents (FM-200, Novec 1230) extinguish fire chemically by interrupting the combustion chain reaction. They require only a small percentage (6--9%) concentration in the room volume. As a result, the storage space for cylinders is much smaller compared to inert gas systems.

Therefore, inert gas systems generally require a larger gas volume to achieve extinguishing concentrations.

Answer : B

The aisle pitch is the total width of a rack row plus cold aisle plus rack row. For 1.0 m racks on each side with cold aisle containment, ASHRAE and TIA-942 recommend the 7-tile rule (each tile ~0.6 m). This ensures enough width for equipment clearance, airflow distribution, and human access.

5-tile pitch is too narrow, restricting containment effectiveness.

8--10 tiles may be used in some hyperscale layouts but are not standard for 1 m racks.

Thus, the correct design recommendation is the 7 tiles pitch rule.

Answer : B

The diagram shows three UPS modules, each 100 kW, connected in parallel to support a 100 kW IT load. That means:

One module (100 kW) can support the load (N).

Two additional modules are installed as redundancy.

This equals N+2 redundancy.

2+N+1 and 2(N+1) imply dual active paths not shown.

N+N+N is not an industry term.

Thus, the correct redundancy level is N+2.