According to the Raised Floor Installation Manual, the best practice for cutting holes in the raised floor tile is to draw a cross on the tile and when making a cut-out do not touch a line and avoid the corners1. This ensures that the structural integrity and load-bearing capacity of the tile are not compromised. Cutting holes anywhere, touching the line, or cutting the corners can weaken the tile and cause it to crack or collapse1.
Additionally, the manual recommends using a drill press or a reciprocating saw with a metal or bi-metal cutting blade, and deburring all sharp edges1.
References: 1: Raised Floor Installation Manual, E. Recommended Cutting Tools, Page 1

Optical fiber cables are composed of a core, a cladding, and a coating. The core is the central part of the fiber that carries the light signal. The cladding is the layer surrounding the core that reflects the light back into the core and prevents signal loss. The coating is the protective layer that covers the cladding and provides mechanical strength and environmental protection. The specifications of an optical fiber cable indicate the dimensions of the core and the cladding in microns (#m), which are one millionth of a meter. For example, a
50/125 #m cable has a core diameter of 50 #m and a cladding diameter of 125 #m. The coating diameter is usually 250 #m, but it is not part of the specifications.
References: Multimode Optical Fiber Selection & Specification - Corning, Optical Fiber OM3 (50/125µm Multimode Fiber), 50/125 Graded-Index OM2 Optical Fiber - OFS

A UPS (uninterruptible power supply) that is categorized as VFD class is not a fit for your mission-critical data centre, because it does not provide adequate protection against voltage and frequency variations. VFD stands for Voltage and Frequency Dependent, which means that the output voltage and frequency of the UPS depend on the input voltage and frequency. VFD UPSs are also known as offline, standby, or line-interactive UPSs. They typically switch to battery power only when the input power fails or goes beyond a certain threshold. However, this switching may cause a brief interruption or a transient in the output power, which can affect the performance and reliability of the ICT equipment. Moreover, VFD UPSs do not filter or regulate the input power, which means that they pass on any voltage or frequency fluctuations, harmonics, or noise to the output power. These power quality issues can also damage or degrade the ICT equipment and the data.
For your mission-critical data centre, you need a UPS that is categorized as VFI class, which stands for Voltage and Frequency Independent. VFI UPSs are also known as online, continuous, or double-conversion UPSs. They provide a constant and clean output power that is independent of the input power. VFI UPSs convert the input AC power to DC power, and then convert it back to AC power with the desired voltage and frequency. This double conversion process isolates the output power from the input power, and eliminates any power quality issues. VFI UPSs also have zero switching time, which means that they do not cause any interruption or transient in the output power when switching to battery power. VFI UPSs are designed to protect the ICT equipment and the data from any adverse effects of voltage and frequency variations, and to ensure the highest level of availability and reliability.
References:
1: CDCP Preparation Guide, page 17, section 2.3.1 2: Understanding UPS Classification: Fuji Electric's Technical Guide3, page 1, section 1 4: Uninterruptible Power Supplies Key Product Criteria5, page 1, section
1 6: UPS Function: Reduced Input Voltage for VFDs - KEB7, page 1, section 1

The four main components of a refrigeration circuit are the evaporator, the compressor, the condenser, and the expansion valve, according to the CDCP Preparation Guide1 and various web sources234. A refrigeration circuit is a system that transfers heat from a low-temperature region to a high-temperature region, using a working fluid called refrigerant. The refrigeration circuit operates in a closed loop, where the refrigerant changes its state from liquid to vapor and back to liquid, while absorbing and releasing heat. The four main components of the refrigeration circuit perform the following functions:
*The evaporator is a heat exchanger that absorbs heat from the low-temperature region, such as the data centre room, and transfers it to the refrigerant. The refrigerant enters the evaporator as a low-pressure, low-temperature liquid, and leaves the evaporator as a low-pressure, low-temperature vapor.
*The compressor is a mechanical device that increases the pressure and temperature of the refrigerant vapor.
The refrigerant enters the compressor as a low-pressure, low-temperature vapor, and leaves the compressor as a high-pressure, high-temperature vapor.
*The condenser is another heat exchanger that releases heat from the refrigerant to the high-temperature region, such as the outside air or water. The refrigerant enters the condenser as a high-pressure, high-temperature vapor, and leaves the condenser as a high-pressure, low-temperature liquid.
*The expansion valve is a device that reduces the pressure and temperature of the refrigerant liquid. The refrigerant enters the expansion valve as a high-pressure, low-temperature liquid, and leaves the expansion valve as a low-pressure, low-temperature liquid. The expansion valve also controls the flow of the refrigerant into the evaporator, depending on the cooling load.
References:
1: CDCP Preparation Guide, page 19, section 2.3.3 2: The Refrigeration Cycle5, page 1, section 1 3:
Fundamentals of Cooling in Data Center6, page 1, section 1 4: The Refrigeration System, Its Four Main Components, And Their Functions7, page 1, section 1

According to the Raised Floor Installation Manual, the best practice for cutting holes in the raised floor tile is to draw a cross on the tile and when making a cut-out do not touch a line and avoid the corners1. This ensures that the structural integrity and load-bearing capacity of the tile are not compromised. Cutting holes anywhere, touching the line, or cutting the corners can weaken the tile and cause it to crack or collapse1. Additionally, the manual recommends using a drill press or a reciprocating saw with a metal or bi-metal cutting blade, and deburring all sharp edges1.
References: 1: Raised Floor Installation Manual, E. Recommended Cutting Tools, Page 1