What Is Static vs. Dynamic Load Capacity? Exploring Server Rack Weight Considerations

As demand for IT resources continues to skyrocket, organizations are packing more processing power into their existing data center facilities. According to the Uptime Institute, the average density of data center racks increased from 5.6kW in 2017 to 8.4kW in 2020. It’s expected to reach 15kW to 20kW by 2025.

Racks and cabinets typically have two to three times as many servers in a high-density data center as in a traditional environment. Servers are often the heaviest equipment, so the weight load increases significantly as more servers are added.

A high-performance computing environment might include as many as 72 blade servers in a rack, along with networking gear. This equipment can weigh up to 1,800 pounds.

Increasing densities put the physical data center infrastructure under pressure to support more heavy equipment. Data center managers must ensure that their racks and cabinets can handle the weight.

Server Rack Weight

Almost all server racks have an interior width of 19 inches because that’s the standard width of equipment. The exterior width of the rack is generally 24 inches. Many data centers use 42U racks, although other heights are common.

Learn more about server rack sizes and dimensions.

Choosing the right server rack for a particular use case begins with understanding the dimensions. Given the dynamic nature of today’s data center, server racks may need to be moved to accommodate changes in the environment. The dimensions and weight of the rack will affect how easily it can be moved and where it can be positioned.

How Much Does a Server Rack Weigh?

The weight of an empty server rack depends on the dimensions and features such as doors, locks, cable management features, sliding drawers, and other options. The construction of the rack also plays a role. Generally speaking, however, a 42U server rack will weigh between 275 and 350 pounds.

Learn more about server rack components.

How Much Weight Can a Server Rack Hold?

Most 42U server racks have a static weight capacity of 2,000 to 3,000 pounds (including the weight of the rack itself). However, some racks designed for light-duty applications may have a static weight capacity of just 1,300 pounds. The weight capacity of the server rack should be greater than the total weight of the IT equipment, cabling, rack accessories, and other components.

Static vs. Dynamic Load Capacity

The static load capacity of a rack is the maximum amount of weight it can support when stationary on leveling feet, and that amount is typically greater than its dynamic load capacity. A stationary object can handle more weight because it’s not subject to the additional stresses of movement.

Dynamic load capacity refers to the maximum weight a rack can handle when rolled on casters, and it’s arguably the more important metric. Odds are high that a rack will need to be moved at some point in its lifecycle. Removing all the IT equipment just to move the rack would be a time-consuming and risky proposition. In fact, many organizations utilize rack and stack services where racks and cabinets are loaded up off-site and rolled into place for immediate use.

Many racks or cabinets have casters, and those are potential weak points in the design. The casters must be able to handle the weight of the IT equipment plus the tare weight of the cabinet. Poor-quality casters can buckle, particularly if the weight isn’t evenly distributed. Some racks include “transport casters” intended to move empty racks from point A to point B. For example, from receiving dock to the data center. It’s important to note the type of casters your rack uses not to overload them. 

The Risk of Overloading Server Racks

Overloading a server rack can cause it to deflect at its weakest points. The rack may appear undamaged, but the distance between the mounting rails could be altered. Even a slight alteration can make it difficult to mount or remove the IT equipment. Moving an overloaded rack puts even greater stress on the x and y axes, increasing the risk that the rack could buckle and harm personnel or damage the IT equipment.

High-Quality Racks and Cabinets from Enconnex

Enconnex offers racks and cabinets for a wide range of use cases. All are manufactured of the highest-quality materials to our exacting specifications. Our racks and cabinets use heavy-duty 3” casters with static load capacities of 3,300 pounds (1,500 kg) and dynamic load capacities of 2,600 pounds (1,200 kg). View all Enconnex racks and cabinets for sale, and contact one of our data center infrastructure specialists today to discuss your requirements.