Data center tier uptime is a system used to categorize the availability of a data center. Several key differences between these tiers include facility design, power supply redundancy, HVAC systems, cooling and power distribution capabilities, physical security features, and IT load capacity.

Since some of these factors can cost thousands or even millions of dollars to upgrade or redesign, it’s essential to understand what makes each tier great before deciding on a facility for your business.

Why is Data Center Tier Uptime Important?

This matters because tier I facilities can recycle their power and are constructed with specific measures to ensure that downtime or external forces, such as physical damage or extreme temperatures, will not compromise the most sensitive IT equipment. Tier II facilities do not have these capabilities and must rely on outside sources for power and climate control. It means they have lower service-level agreements (SLAs) and are more susceptible to outages and failure.

The Tier system is a standard benchmarking tool for data centers, which the Uptime Institute has adopted. It started as a way to measure the availability of technical infrastructure but has expanded to include business continuity planning and disaster recovery. Each tier has its requirements, which you can read about here. The standards are focused primarily on data centers in the United States but provide information on international standards.

The Uptime Institute has established a Data Center Tier Uptime rating system to help organizations decide where to house their data and choose a facility that will provide them with the best protection for their investments. It does this by providing a set of criteria for organizations to evaluate their facilities against and assigning each facility a tier designation based on its performance in those categories. This designation helps people make more informed decisions about where to house their data and offers organizations valuable insight into what they can expect from the facilities they use.

Uptime Institute Data Center Tier

The Uptime Institute has created the Tier Classification system to provide a framework for building owners and operators to establish, promote, and manage data center capabilities that meet the demands of their clients. The Tier system is designed to provide a common language to enable meaningful comparisons of data center capabilities and aid in evaluating and defining data center requirements.

Tier 1

One non-redundant distribution line serves IT equipment or one uplink per server. It is usually found in large companies with their own data center, with a focus on the ability to perform operational activities during working hours and backed up by UPS.

The uptime rate is 99.671%, or within a year, and the maximum disturbance tolerance limit is 28 hours.

Tier 2

Fundamentally, it is almost the same as Tier 1, but it has been added with a redundant component (already having backup resources, meaning redundant). In addition to UPS, Tier 2 data centers must be equipped with generators in preparation for rotating blackouts from the power grid.

The uptime rate is 99.741%, or it only has a down tolerance of 22 hours a year.

Tier 3

Tier 3 data center facility equipment must have more than one power source and network (multi-network link) so that the “no shutdown” requirement can be fulfilled in the data center tier 3.

Uptime rate of 99.982% or downtime tolerance in a year for a maximum of only 1.5 hours. Usually, the tier 3 data center is almost the same as the performance of the tier 4 data center.

Tier 4

Like tier 3, this tier 4 data center only has a downtime tolerance of 30 minutes a year.

Such is the meaning of the tier in the data center. For more details, see the Uptime Institute website for tier certification in the data center.

Green Data Center Certification

Data centers are notorious for consuming much energy; they use more energy per square foot than any other type of commercial building. These facilities support the IT equipment in their offices and power remote locations through virtual private networks (VPN). Energy consumption is one of the main reasons there has been such a strong push toward green buildings over the past few years.

It is important to note that Green Tier Certification differs from ISO 14001 and ISO 50001:2011 Energy Management Standard from the International Standards Organization (ISO). The ISO standard offers guidance on how to improve energy efficiency.

It is interesting since The Uptime Institute Tier III certification requires a data center to implement specific environmental control and physical security processes. The environmental control process includes monitoring temperature, humidity, airflow distribution, dehumidification system operation, and other factors that can affect the environment in a given space.

However, to get certification for a green data center or sustainable data center, a data center must prove efficiency (Power Usage Effectiveness) below 1.5 and a carbon footprint level below 50%. We will now understand the importance of cleaner energy sources for a data center.

Green Grid Classification

The Green Grid is an industry-backed consortium that has developed a set of environmental sustainability standards for data centers. It’s important to note that these standards are not for the companies themselves but for their facilities—that means that whether or not a company is certified depends on the data center it’s affiliated with.

There are three tiers of certification: Platinum, Gold, and Silver. You can view the details of the certification criteria at, but here’s a quick overview.

To qualify for any tier, a facility must meet all the requirements below and have a documented energy management system. Each tier increases the requirements necessary to allow.

The first general requirement is to consume less power than your facility would otherwise by looking into ways to reduce power consumption through server consolidation and more efficient IT equipment use. Tier 1 also requires using renewable energy (specifically solar or wind) on-site. However, there isn’t any extra credit for using even more than what you’d get from meeting this requirement.

Read next: Can Amazon Data Center in Singapore Be Greener at Large Scale?


If you ever want to run a data center or know about the industry, you should be familiar with the Uptime Institute’s Data Center Tier. The Uptime Institute is an independent non-profit organization that provides standards and guidelines for the data center industry.

The data center is the backbone of today’s world community activities. The data center business is one of the most desired investments by investors. Datacenter profits are higher than other businesses with virtualization or cloud systems, so their gross profit is around 70%.

Therefore, investing in green energy and technology in data centers should be easy. The problem is how high our moral level toward environmental awareness will be in the future.

Hopefully, this short article can help you understand the Tier Data Center system implemented by The Uptime Institute, which is widely used in data centers worldwide. It can sway stakeholders to invest in green data centers immediately.