Data Center Design Consideration: Space Planning

A data hall houses computers and communications equipment that delivers, store and process information. This is the heart of the data center that operates all mission-critical applications. You need to address 2 key considerations:


(1) Restricting Access

Access to the data hall shall be limited and restricted to only authorized people and to minimize any accidental damage to the computer systems.

(2) Maximizing Floor Space

Floor space in the data hall is extremely valuable due to the high investment placed into the supporting infrastructure. It includes precision air-conditioning, standby power supply, equipment-safe fire protection system as well as security and monitoring systems.



"Non-essential" Items

Sometime "non-essential" doesn't mean useless. To maximize the use and enhancing the security of the area, "non-essential" items should be located outside the data hall. Examples of these items are:


(A) Operating Console / Network Operation Center (NOC)

It houses computer stations connect to the equipment or critical facilities in a data center. NOC may be situated in a separated room / area next to the data hall. Staff can monitor and manage the various systems here and enter the data hall only when they install cables or equipment. It also ensures that the operations and maintenance of the console do not affects the racks/cabinets inside the data hall.

(B) Gas Suppression Systems

Gas Suppression Systems such as FM200 are frequently used in a data center for fire fighting purposes. Gas is used over water as they do not damage the data hall's equipment when discharging. Unlike water, gas should be stored in gas cylinders. Placing these cylinders outside the data hall would allow your technicians to serve them easier.

(C) UPS Batteries & Generators

Uninterruptible Power Supply (UPS), high voltage switchgear and Genset are critical to supply backup power and are usually isolated in different rooms / area:

• Batteries will discharge gas during charging.
• Batteries contain acid that may leak and damage equipment
• Prevention of fire
• For safety reason, only qualified electrical workers are allow to enter the room and serve the high voltage facilities

(D) Air Handling Units (AHU) / Computer Room Air Conditioners (CRACs) Units

It's commmon for a dedicated AHU / CRAC Units to be used in a data room which ensure air from other parts of the data center is not recirculated into the critical area. In addition to being bulky, the AHU or CRAC Units generates heat and maintenance issues. AHU / CRAC Units, therefore, are unsuitable to be placed inside a data hall. Should they be installed in a data hall, they should be placed along the hot aisles.

Maintenance Area

It is important equipment installed in a data center can be repaired or replaced easily without affecting normal operations. Unless we absolutely sure that rear access to the equipment is not required, no equipment should be placed along a wall such as switchgear.

A minimum space greater than the depth of the equipment is required in front or at the back of the equipment which allows

- New parts' installation
- Maintenance or repair
- Airflow (such as hot aisle or cold aisle design)

For racks, a minimum of 1m clearance is observed between racks. A 1.5m radius is usually kept at the end of cabinets / racks which facilitates the use of trolley to move heavy equipment into the aisles.



Raised Floors

Typical raised floor inside a data hall / NOC are 150mm to 300mm (or higher depends on the floor height or design request, you may refer to the international standard / advice in TIA-942 or Uptime Institute). A ramp is usually created at the entrance to bridge the different in heights. It also allows trolley to move heavy equipment. The gradient of a ramp should not be steeper than 1:12.

Per normal practices, power cables (high voltage) are usually put under the raised floor, whereas data cables are usually put inside a cable tray overhead.

Cable Routing

We suggest power cables are separated from data cables. It ensures that the power cables do not pose any electromagnetic interference (EMI) to the data cables. Per previous advice, power cables are laid under the raised floors, whereas data cables are laid overhead.

In addition, data and power cables should be entered a data hall (or other faciliities' rooms) at opposite ends of the area whenever possible to avoid too many cables on one side and EMI problem.

Layout of a data center should be designed to minimize the run of data or power cables. For example, power cables enters the data hall and are routed through

- Riser (Cable Entry)
- Electrical Distribution Box / PDU (Power Distribution Units)
- UPS (High Voltage Switches, etc.)
- Equipment Racks

with minimized distance if they are located near each other relatively.

Expansion

Data Center are used to serve enterprises, government or other organizations. As business or services developed, the demand for faster applications and data storage grow as well. You are advised to allow space for expansion purposes. This expansion space could be located near the entrance of a data center / data hall which allows easier renovation and the installation of new equipment , cabinets and racks.

Cabling, cable trays and empty racks, where feasible, can be pre-installed in the expansion areas. This would minimize the amount of work to be done and the disruption of data center operations / equipment during expansion.



About SMA

Strategic Media Asia (SMA), a critical infrastructure training and event organizer based in Hong Kong, provides an interactive environment and opportunities for members of IDC industry and engineers to exchange professional views and experience on critical infrastructure and E&M facilities.

SMA is one of the CPD Course Providers of the Chartered Institution of Building Services Engineers (CIBSE).

For details of other data center courses and seminars, please visit our website at http://www.stmedia-asia.com/trainings.html.

4 Ways to Extend the Life of UPS Batteries

Data center backup power is a crucial element to uptime and availability. During an outage, Uninterrupted Power Supply (UPS) enables the switch from utility power to backup generator power. But there is a relatively unreliable and expensive variable to most UPS: batteries.

Batteries represent three evils: They are big, they are expensive, and they are expendable. Anything you can do to prolong the life of your batteries will indeed extend the availability of your data center.

So here are four ways that data center facility managers can extend the life of their UPS batteries.


(1) Buy the right UPS battery for your data center


In a data center, UPS is designed to fully discharge the battery source within 20 minutes. This is called high-rate discharge. High-rate batteries have thinner plates and more plates than lower-rate batteries, but as a result high-rate batteries can lead to a shorter lifespan.

There are many other factors in buying UPS batteries, such as the life expectancy, voltage, front or top access, flag post or inserted post, and other considerations. For example, a small format valve regulated lead acid (VRLA) battery has a relatively low first cost but lower reliability. Meanwhile, a nickel cadmium (NiCd) battery has the best reliability and longest service life, but the first cost can be four times as much as other batteries.

Data center manager must also be aware of potential manufacturing problems such as faulty post seal design and internal connection problems.


(2) Install, operate and maintain batteries correctly


Incorrect installation can lead to shortened battery life, as can improper maintenance. Good maintenance means giving the batteries well ventilated air that is as close as possible to 77 degrees Fahrenheit, and making sure that all batteries in the string are getting air within 3 degrees Fahrenheit to ensure that some of the batteries don't age more quickly than others.

Why? Mixing batteries of different ages or internal resistances can prompt batteries to die more quickly. Regular inspections of the batteries can unveil problems such as loose intercell connections and damaged post seals, which can lead to corrosion and even fires.

Data center manager should also be aware of the battery's discharge status as well. A fully or nearly fully discharged battery that isn't recharged within 48 hours can lead to damage. Overdischarging a battery can cause recharge problems, and excessive discharging -- for example, if a data center does weekly testing of its backup systems that includes battery cycling -- can reduce battery life.


(3) Monitor the UPS batteries' capacity


When the internal resistance of a battery rises due to normal aging factors such as corrosion, and when it has increased by as little as 30%, it's time to replace them. This is most often measured through capacity testing, as most manufacturers say that when a battery drops to 80% of its original capacity, it's cooked!

Users should perform capacity testing on their batteries based on IEEE standards; in particular, IEEE 1188 or IEEE 450.


(4) Flywheel UPS in conjunction with battery UPS


When flywheel UPS is installed with battery UPS, the flywheels can often handle the shorter power outages that happen more often and can prevent the batteries from cycling. The flywheel UPS also helps to extend battery life by two years preliminary.

In addition, flywheel can filter out the 'dirty power, such as little power blips and spikes. The batteries would filter those spikes out but if you hit the batteries with those spikes, it will kill the battery life.



About Strategic Media Asia Limited


Strategic Media Asia (SMA, www.stmedia-asia.com) is a professional training program and seminar organizer for corporations specialized in data center design & build, mission critical facilities, telecommunications infrastructure, financial IT and colocation services. Currently, SMA delivers a series of critical infrastructure training courses and qualification programs in Hong Kong and Macau.


For details, please visit www.stmedia-asia.com/trainings.html.