FAQ

Mechanical – Electrical -Architectural

A/C Equipment
Use fewer, larger, more cost effective, energy efficient cooling units isolated in a separate mechanical equipment room

Effectiveness
Ventilation effectiveness, delivers air precisely where needed anywhere in the room, all the way to the top of the cabinets

Efficiency–Less Energy
Precisely delivering only the amount of cooling necessary from right sized equipment saves energy and lots of it––also preserves the life and function of the IT equipment

Effective N+1 Redundancy
When the A/C equipment is clustered together feeding into a common mixing box with dedicated pressurized air distribution only one unit is required to provide genuine N+1 redundancy regardless of the room size

Liquid Cooled Piping
All piping and/or hoses are easily and conveniently placed in the upper utility plenum for distribution from chillers to cabinets as a best practice and in accordance with building codes––contrary to overhead piping methods in on-slab rooms.  Air flow is never effected while working on liquid cooled piping.

Adjustable Airflow Control
Every airflow assembly has an easily adjustable opposed blade damper to balance the airflow throughout the room.

Containment
Is not necessary, because Interstitial provides ventilation effectiveness pushing volume-controlled air all the way to the top of every cabinet

Simple Design Engineering
The pressurized air plenum assures air throughout the entire space–to ALL servers. Therefore, eliminating the complications and generally unsuccessful attempts to deliver air in complex flooded room designs.

Service and Maintenance
Fewer, larger cooling units require less service and maintenance of the cooling equipment. Maintaining the floor surface is a normal cleaning procedure. The dirt and debris usually found in a single level floors air stream is contained in the upper utility plenum making for cleaner airflow.

Gasketed Cutouts
Aren’t required because the air is separated from the cables in its own dedicated plenum and doesn’t leak through the floor panel joints

Security
Install the A/C equipment in a separate mechanical equipment room so the service technicians don’t need to enter the white space

Simple Installation of Power
Laying power cables in the floor is as simple as demonstrated in the video on the “How Interstitial Works” page. In that installation A, B and C cables were installed for 232 cabinets in 1 day.

Power Cables vs. Busway
It is much faster and less costly to use underfloor power cables than overhead open track busway.

Underfloor Cable and Wire Installation
Installing wiring in the upper utility plenum is a much faster and safer install for technicians because the cables are not installed in contained airflow plenum spaces and there’s no need for ladders with underfloor wiring.

Plenum Rated Wiring Not Required
Conventional raised floors are generally air plenums and therefore require plenum rated wires and cables. Interstitial upper utility space is not an air plenum, it’s a dead air space, therefore plenum rated wires are not required.

Bonding/Grounding
Reduced number of ground points. Up to 200’ with a single ground point meets NEC 645.15, IEEE 1100, ANSI/TIA 942 and J-STD-607-A. Resistance does not exceed 0.1 Ω.

Cable Tray
The steel that separates the air plenum from the utility plenum serves as a built-in cable tray. Additional levels of trays can be elevated above that divider for installing additional cabling. Overall, fewer cable trays.

Electrostatic Discharge (ESD)
The system will dissipate ESD. Industry accepted ESD control is achieved with our standard HPL, however, we offer a variety of surface materials for more stringent requirements if required.

Electro Magnetic Pulse (EMP)
The system meets all criteria as a Signal Reference Structure (SRS)

Fire Detection
Isn’t required in the sterile air plenum and the upper utility plenum is a dead air space so if detectors are used, they can be distributed over a 450-sf area.

Building Size
When designing a building with Interstitial the data center can usually be 30% smaller in comparison to an on-slab flooded room design. Or, 40% more cabinets can be added if there is sufficient power available.

Building Height
Generally, the building height can be reduced by 20% when using Interstitial vs. an on-slab flooded room design.

White Space and Gray Space
Position high-density equipment anywhere in the white space and install all of the mechanical equipment in a single equipment room up to 200’ from the load.

Flexible / Adaptable
Interstitial is the simplest means to distribute air, water, power and cables. Adapting to any form of liquid cooling is simple––just install your pipes or hoses in the upper utility plenum.

Moves, Adds and Changes
Moves, adds and change are simple, and don’t require a reconfiguration of sprinklers, detectors or lighting because there’s no need for containment.

Lighter Slab Structure
The truss design of the Interstitial under structure distributes the load over a larger area so the concrete slab can be lightened by 34%, which could apply to a new build or make an older building with a lighter slab an attractive alternative.

No Need to Increase Roof or Ceiling Structure
Placing all wiring and cabling underfloor means no need to reinforce the roof. When building an on-slab flooded room design the wires and cables are suspended from the roof, and/or ceiling structure adding considerable weight and generally requiring reinforcement.

Less Interstitial Required
Since the white space is smaller (up to 30%) the amount of Interstitial required is less.

Absolutely. When Interstitial set out to build a precision air distribution system, effective and efficient airflow was critical. Why? Because, if a server fan has to work harder than its baseline it can increase the server’s energy consumption by 40%.

The two summary tables below are extracted from a CFD report. Each cell represents a server with the CFM for that server. There are 19 servers in each cabinet. Each column represents a cabinet, the collection of cabinets makes up one side of a cold aisle.

When using Interstitial 100% of all servers receive the required airflow (without containment), compared to an on-slab flooded room design using cold aisle containment having only 67.4% of the servers receiving the required amount of airflow—wasting energy.

Furthermore, the variation of airflow within the Interstitial cold aisle, from end to end and top to bottom is only 6.8%, whereas the flooded room design with containment has a variation of 35.1%—also wasting energy,

For more detailed CFD information demonstrating the Venturi effect that occurs in the cold aisle of on-slab flooded room design resulting in server airflow shortfall, visit our Library and download paper #9, “Case Study—31% Space Savings” p. 18-28.

It will. Interstitial was designed to provide maximum flexibility by simply relocating airflow grates to any module where air is required. And, it does so without the use of costly and cumbersome containment devices. So long as you have the cooling equipment available to meet the heat loads of the equipment. The video demonstrates the ventilation effectiveness of Interstitial, which can be accomplished anywhere in the room.

Interstitial provides precision air distribution where you need it when you need it… If liquid cooling were required for some IT equipment those lines can be installed under the floor in the upper utility plenum to prevent any leakage from damaging IT equipment.

 Data Centre cabinet densities and energy consumption has become astronomical to the point where entire regions face electrical energy supply concerns. This has required re-thinking data center cooling approaches such as rear door heat exchangers, a variety of direct to chip cold plates, and immersion tanks. Solidifying corporate plans around these ever-developing cooling approaches is fraught with risk and complexity. All the attention directed to liquid cooling assumes that higher density cabinets cannot be cooled by air. But at what cabinet density does liquid cooling become mandatory? The tipping point to introduce liquid cooling depends on the efficiencies of the air distribution system chosen. With Interstitial’s Electro-Mechanical distribution system, for example, air cooled 50 kW cabinets are no problem. If ever there is a need to go beyond 50 kW, the same Interstitial distribution system will easily and more efficiently accommodate liquid cooling as well. Imagine the flexibilities an Interstitial decision made now can offer over the long term—whenever and whatever direction your company chooses to go! 

Interstitial’s pressurized air distribution plenum provides precision cooling for IT Equipment setting it apart from other air-cooled methods. The CFDs in the PDF demonstrates a compact 5 MW, 8,250 sf space, featuring effective cooling for 100–50 kW 32” X 48” cabinets using 20 Liebert DSE 265s while providing effective N+1 redundancy. 

Cables and wires are housed in the upper utility plenum, where they are completely isolated from the air stream. They are always up off the floor and easy-to-reach. Working on them always takes place in the ambient room environment. Because the wires are separated from the air stream there’s no need for costly plenum rated cables, which saves a lot of money. The system is stringerless regardless of finished floor height and, without compromising structural integrity, an unlimited number of panels can be removed for fast, safe wire installation; Wires and cables can be separated from each other in a variety of easy-to-install and easy-to-relocate modular cable trays. Overall it’s far safer and more flexible than using overhead cable tray.

Example: A client installed all the power cabling from A, B, and C UPS to 232 cabinets in 1 day.

There’s never a need to work using dangerous ladders.  In the US there were 22,710 injuries and 161 fatalities in 2020 due to ladders.

Interstitial allows you to save energy and lots of it… For over 50 years air delivery in computer rooms has relied on “precision” down-flow air handling units (AHUs) used in conjunction with cable-clogged, leaky, conventional raised floors. The fact that this doesn’t work is demonstrated by the universal plague of hot spots, cold spots, air handler short cycling, negative air flow (where cooled air actually flows back down under the floor through perforated panels) and the need for containment methods . These problems exist even though the typical data center design provides at least 25% more air conditioning than is actually required to meet the room’s heat load. In on-slab flooded rooms energy is wasted because of high velocity air entering the cold aisle creating a Venturi effect resulting in many server fans having to work harder, consuming up to 40% more energy, and there’s a wide variation of airflow within the cold aisle wasting energy.  Interstitial delivers the required amount of air to each cabinet regardless of kW.  If an aisle has cabinets with varying kW heat loads the airflow panels will deliver what is required rather than over cooling the entire aisle. Interstitial is a precision air delivery system solving all of these typical problems, even in the demanding environment of critical (Tier I—IV) data centers. It does so by allowing the use of larger, more energy efficient cooling equipment sized to match the overall heat load. The A/C equipment can be located in a separate mechanical room (200′ from the furthest cabinet), if desired, and still provided uniform, reliable pressurized air delivery to the entire data center space.

Not only don’t you need CRAC units around the perimeter of the room, or installed through the middle of the room, you don’t need CRAC units in the room–period. For example in this picture you see there are no CRAC units installed in the room, they are behind the single wall far away from the opposite wall (140 feet). In fact we’ve shown that with Interstitial it is possible to move air 160 feet from the unit discharging it, meaning you could build a 25,000 sf room with all the air coming from only one side of the room. This benefits security since all service and maintenance of the cooling equipment is performed outside the white space.