Important Exin CDCS Exam Questions

Answer: B

Explanation:

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: B

Explanation:

High relative humidity (above 80%) creates a serious risk for corrosion of electronic contacts, printed circuit boards (PCBs), and metallic components. Moisture in the air condenses more easily, especially when surfaces are cooler than ambient dew point. This can lead to oxidation of connectors, degradation of solder joints, and eventual failures in ICT hardware.

Electrostatic discharge (ESD) risks, by contrast, increase at low humidity (below 30%) because dry air promotes charge buildup. Therefore, option C is incorrect here. Similarly, option D (cooling risk from wet-bulb temperature) applies to evaporative cooling efficiency, not directly to ICT risk.

ASHRAE recommends data centers maintain RH between 40--60% for optimal reliability. Values above 80% RH are considered outside the recommended operating envelope and significantly increase the risk of corrosion, especially in the presence of airborne contaminants like sulfur dioxide (SO) or hydrogen sulfide (HS).

Therefore, the verified risk at 85% RH is corrosion-related degradation.

Answer: A

Explanation:

For balanced three-phase systems: where .

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Answer: B

Explanation:

The data center life cycle is typically divided into four stages:

Design (scope, architecture, planning)

Implement (construction, installation, testing & commissioning)

Operate/Optimize (day-to-day operations, maintenance, continuous improvement)

Retire (decommissioning and migration)

Testing and commissioning occur in the Implement stage, after construction but before handover. This includes Integrated Systems Testing (IST), which validates that all systems (electrical, cooling, fire protection, telecom) perform to design intent and redundancy requirements.

Without commissioning, the data center cannot be certified or considered operational.

Answer: C

Explanation:

ANSI/TIA-942 specifies minimum floor live load capacities based on Rated levels:

Rated-1/2: ~7.2--8.4 kPa

Rated-3: 12 kPa

Rated-4: 15 kPa

These values ensure raised floors can support racks, cabling trays, cooling units, and maintenance loads without structural compromise. For Rated-3, concurrent maintainability requires higher floor robustness to handle additional infrastructure.

Therefore, the correct requirement is 12 kPa.