Server Room Design

There are so many elements to consider when exploring the best way to effectively design and cool a server room; from the nature of the space (has it low ceilings, does it have a raised floor etc.), the extent of cooling required, the level of environmental monitoring needed, the best method of fire suppression, the list goes on. However with Critical Power’s extensive knowledge and experience, we can offer an unbiased view on the very best solution for you. By understanding your requirements and your space, we will explore and make recommendations on the many options available, including:


In some instances, there may be a requirement for portable cooling. There are a wide range of portable air conditioning units, ideal for single room or multiple sites, which principally fall into three types:

  • Exhaust Tube Units: designed to disperse the heat via an exhaust tube
  • Split Type Units: ideally suited for large capacity environments, such as server rooms or large offices
  • Evaporative Coolers: ideal for comfort cooling where conventional air conditioners struggle

Easy to use, these systems can be simply plugged in exactly where you want them. Fitting with Critical Power’s environmental stance, we ensure that any portable air conditioning units we supply are energy efficient, deliver reduced emissions and offer low running costs.


Offering amazing flexibility in where you can deploy your data centre hardware, fresh air cooling uses clean air pulled in from the outside, via a fan. These systems remove the need for expensive cooling equipment and are suitable for small to medium businesses, or a large number of hardware deployments across labs and data centres. They also help to reduce hours of controlled air conditioning chilling, which obviously ultimately helps save on operational expenditures and lowers the overall power usage effectiveness (PUE). Key features include their ability to:

  • Manage high temperatures and humidity levels
    – Even up to 45°C/113°F at a 29°C maximum dew point
  • Meet air quality standards
    – Uses clean outside air in both air-side and water-side environments
  • Facilitate deployment of chiller-less data centres to almost anywhere
    – Where there are relevant climate conditions
  • Be able to operate all year-round
  • Reduce operational costs
  • Lower IT environmental impact

Using the very latest technology, in row cooling is purpose built and directly cools the racks. By separating the rack and the air conditioning unit, the data centre heat management is optimised, resulting in increased reliability and more design freedom in the layout of the data centre. Perfect for restricted spaces, or where there is an absence of a raised floor, or where there is fluctuating server rack loads; this approach can address challenging situations and work with existing server technology. Compact and suitable for a variety of racks from different manufacturers, it can also be easily adapted to modernise cooling systems in existing buildings, while being:

  • Adaptable: intelligent air flow system that self-adapts to changing conditions
    – Suitable for small and medium data centres with either raised and non-raised floors, and rooms with low ceilings
    – Works equally well in contained and open environments for either hot-aisle or cold-aisle capture
    – Air, water, glycol and chilled water systems available
  • Flexible: four different cooling systems are available, each in a variety of sizes (up to 40KW) with indirect free cooling:
    – A/AS-System – direct expansion
    – GS-System – direct expansion and plate condenser
    GES-System – direct expansion with indirect free cooling
    – CW-System – chilled water cooling
  • Precise: targeted cooling of high-density racks, the horizontal air conduction means the cold air takes the shortest route to reach the rack
    – Automatically balances the airflow and cooling capacity depending on need
  • Effective: delivers cooling close to the server heat source for efficient and effective data centre heat management
  • Variable: featuring adjustable speed EC plug fans and flexible capacity digital scroll compressors
  • Controllable: provides 24/7 precise environmental control for cooling, humidity control and air filtration
  • Ability to monitor and control all the components inside and outside the unit to improve performance and report rack temperatures
  • Independently controlled 5 speed fans to enable system to respond to differing air temperatures
  • Accessible: designed and built for ease of maintenance with access from the front or rear of unit

These devices replace previous air conditioning units to ensure that temperature, air distribution and humidity are monitored and maintained. Using a variety of techniques, the CRAC cools the air generated by the racks. This can involve dispersing the air through an elevated floor with the air rising through the perforated sections to form cold aisles. The result is that the cold air flows through the racks, picking up the heat as it goes, before exiting from the rear. The air moves from these hot aisles behind the racks and returns to the CRAC intakes positioned above the floor.


An essential component of any data centre or server room design is an effective fire suppression system. With the heat generated by data centres, plus potentially faulty equipment and damaged wiring all increasing the risk of fire, it is so important to minimise the damage a fire can cause. Whether for a room or a cabinet, the Pneumatically Actuated Fire Suppression Systems (PAFSS) detect the fire source and extinguish it early to minimise the damage of valuable assets and enable a quicker recovery of operations. Specifically designed to protect electrical equipment, Critical Power’s fire suppression approaches offer:

  • Self-contained pneumatic systems: require no external energy or power supply and are situated where the greatest fire risks are
    – Extinguish a fire automatically without human involvement
  • Rapid reaction to a situation: upon identifying flames or heat, the pressurised, linear detection tubing bursts and activates the cylinder valve to open and release the extinguishing agent
  • Customised methods: there are two ways of having a carefully designed fire suppression response depending on your particular environment:

ROOM SUPPRESSION: this focuses on a larger room environment, where the suppression system will also require pressure relief venting:

Inert gas fire suppression to reduce oxygen. Using a combination of Argon / Nitrogen and sometimes a small element of CO2 this approach discharges its payload within 1-2 minutes and displaces the oxygen in the server room to reduce the O2 level to below 15% (but above 12% bearing in mind potential personnel in the room) and suppress the fire.

Chemical / Synthetic gas fire suppression. Operating on a cooling mechanism, these systems usually deliver their payload within 10 seconds and use less gas, so do not significantly reduce oxygen levels, however high doses of the synthetic or chemical agent can be toxic

CABINET SUPPRESSION: a more focused in-cabinet fire approach, this quickly targets the fire directly to minimise threats to the business continuity:

Responsive detection and suppression. Concentrated on protecting high risk, high value equipment, this approach protects the cabinets from within using minimum extinguishing gas and can be moved with the rack. Easy to specify, install and maintain, this modular approach means the payload is released within the protected enclosure, where a fire can be detected early and directly treated. As it discharges a smaller amount of gas suppression, it also offers a more environmental solution.

  • Tailored to setting: as most server rooms and data centres are occupied, the fire suppression system must be suitable for clean air environments
  • Extensive monitoring tools: these are recommended for any server room or data centre environment and include having a control panel, smoke detection system (in all voids i.e. room, ceiling and floor), audible alarms and warning signs
  • Adherence to strict guidelines: fire suppression agents can be dangerous if not designed correctly, Critical Power therefore follow all the key, relevant standards

When considering server room design and its cooling, there is much debate about the subject of a raised floor versus slab floor construction. Whereas traditionally nearly all data centres had raised floors, more recently these have become less the norm, however there is still a place for a raised floor design to improve cooling effectiveness depending on needs of the business. At Critical Power we believe a raised floor will offer:

  • Effective cooling – delivery of cooling air through perforated floor tiles
  • Flexibility – ability to easily rearrange perforated tiles, should racks be moved
  • Accessibility – accommodates potential future changes, such as being able to add cooling or electrical infrastructure
    beneath the floor to in-row cooling units or heat transfer direct to servers
  • Adaptable – offering future flexibility, particularly when in a multi-tenant facility