Exin CDCS - EXIN EPI Certified Data Centre Specialist

A halocarbon gas-based fire suppression system primarily extinguishes fires through heat absorption. In contrast, an inert gas-based system works by reducing oxygen levels to a point where combustion cannot be sustained. Halocarbon agents, like FM-200, absorb heat from the fire, cooling it down, whereas inert gases, like nitrogen or argon, lower oxygen concentration.

Detailed Explanation:

Halocarbons are effective in quickly cooling flames and are suitable for electronic environments due to their fast action. Inert gases displace oxygen to suppress fires, making them ideal in occupied spaces where human safety can be managed during a fire event due to slower discharge times.

EPI Data Center Specialist References:

EPI training distinguishes between these suppression mechanisms, noting the importance of selecting the correct system based on specific needs like quick response versus oxygen displacement for environments with sensitive equipment.

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.

Perforated tiles should be located in front of equipment racks, aligned with cold aisles, to deliver supply air directly to server intakes. Best practice is one perforated tile per rack, adjusted based on airflow requirements and rack load.

Placing tiles at the back (A) disrupts airflow.

Spacing every 5th rack (B) provides insufficient cooling.

Placing near AC (D) causes uneven distribution and pressure loss.

Thus, option C is correct.

A Rated-4 facility requires dual active utility feeds, each from an independent substation, but they may come from the same utility provider if substations are geographically separate and independent.

Option A is too strict; ANSI/TIA-942 does not mandate two different companies.

Options C and D do not provide true independence and would fail Rated-4 requirements.

Thus, the minimum is two substations, possibly same provider.

Halocarbon agents such as FM-200 (HFC-227ea) and Novec-1230 (FK-5-1-12) are both defined under NFPA 2001 and ISO 14520 as clean agents, but their required design concentrations and physical properties differ. When calculating agent quantity, the minimum extinguishing concentration (MEC) and safety factor (S) must be taken into account. The S-factor is specific to each agent and reflects differences in molecular weight, density, and flame suppression chemistry.

For Novec-1230, the required design concentration is generally lower than for FM-200 (around 4.5–6% vs. 7–9%), but the calculation formula is the same except for substituting the correct S-factor. Therefore, you cannot reuse the exact formula parameters from FM-200; you must change the S-factor and apply Novec-1230’s physical constants.

This ensures compliance with NFPA 2001 Annex C, which provides correction formulas for room volume, temperature, and specific agent type. Using the wrong S-factor could result in underfilling or overfilling, compromising fire safety or increasing cost unnecessarily.

To ensure uniform air distribution, there must be a buffer zone between CRAC/CRAH discharge and the first row of racks. Industry best practice (ASHRAE & TIA-942) specifies at least 1.2 m (4 ft).

Less than 1.2 m risks air velocity hotspots and turbulence, disrupting cold aisle containment.

More than 1.8 m wastes valuable floor space without added benefit.

Thus, 120 cm is the recommended minimum.

When installing a raised floor, the best starting point is typically from 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 controlled placement 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.

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 2(N+1) configuration implies two independent UPS systems, each with N+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 the 80 kW load, this setup implies that two separate N+1 systems are running, providing reliability and fault tolerance for the data center’s power needs.

Detailed Explanation:

The N+1 notation denotes that each system has one additional unit beyond what is needed to carry the load, providing redundancy. With 2(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 as 2(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.

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.