Racks and Enclosures Should be an Afterthought

Monday, April 2nd, 2012

In an article for Mission Critical magazine, Steven Leidig, manager of enclosure engineering at Crenlo, discusses the importance of having an established design in place before ordering racks and enclosures for a data center.

Building an efficient data center requires significant analysis of a number of factors, including the number and type of servers needed, expected power usage, cooling requirements, airflow design, footprint, layout, cabling paths, and more. Each of these considerations can affect the others, and as such, the rule of thumb is that procurement should not take place until the design has been firmly established— a rule that is often broken, especially when procuring server racks and enclosures.

As the units in which the equipment will be installed, server racks and enclosures are arguably the components that will be most affected by all the other data center design factors. There is no one-size-fits-all solution when it comes to the enclosures, yet often, they are treated as such.

As manager of enclosure engineering at Crenlo, Steven Leidig is responsible for the design of custom and new enclosures, including the company’s Emcor brand. In his 16 years as an engineer, Leidig has spotted a trend that he believes is not only causing delays in data center projects but also driving up the long-term costs of operation.

“When we get a purchase order with little more information than cabinet width and depth, that’s a sign that either the procurement of the enclosures is taking place too early in the design process, or there is a gap in communication between the data center designer and the person procuring the equipment,” says Leidig. “This problem is so prevalent that in the last year, about 17 percent of our incoming requests for custom or modified enclosures provided too little information for us to be able to fulfill the order. We estimate that the lack of information provided on each of these requests delayed manufacturing by an average of 19 days.” See figure 1.

  Figure1_Buying the right enclosure depends on having an established design in place

Figure 1. Chart shows how lack of information from the buyer can delay projects.

In addition to delaying how quickly the customer receives the product, providing too little information to the supplier can result in a product that will lead to even more project delays and increased costs during and after installation.

“Today’s enclosures are available in nearly limitless configuration options—in terms of size, modularity, shelving, weight load capacity, accessories, side panels, doors, bases, shielding, and finishes,” says Leidig. “A buyer who doesn’t make these configuration decisions based on the overall data center design is bound to experience increased costs related to things such as inefficient access to serviceable components, the necessity for costly in-house modifications, lack of flexibility for future growth, inefficient airflow design, and more.”

In order to avoid the aforementioned delays and costs, Leidig recommends that procurement not take place until the following seven questions can be answered by the buyer.

What is the total weight of equipment being loaded into the enclosure?

Although this information may seem trivial, Leidig stresses that nearly every design choice of an enclosure depends on weight load capacity, making it one of the most critical pieces of information to provide to the manufacturer (see figure 2). Despite its importance, Leidig says buyers rarely provide this information.

 Figure2_Buying the right enclosure depends on having an established design in place 

 Figure 2. Areas subject to potential failure due to insufficient weight load capacity.

“What buyers often fail to realize is that proper selection of nearly every component of an enclosure should be based on weight, including casters, levelers, shelves, drawers, sliders, frames, tie-down hardware, and anti-tip bases,” explains Leidig. “Often, we don’t feel comfortable recommending a solution until we have the weight-load information, because recommending something with insufficient capacity could pose safety concerns and ultimately result in equipment damage.”

In what kind of environment will this equipment be installed?

The reliability, performance, and efficiency of network equipment depend on the equipment’s level of protection against harmful environmental factors. With today’s network equipment no longer limited to phone closets, new environments pose new protection challenges.

“The operating environment heavily influences recommendations on components such as vents, filters, and gaskets, as well as the type of materials used and finishes applied to the exterior of an enclosure. What might be right for an a/c room probably wouldn’t be right for a factory floor,” says Leidig. “As electronics are being put into these new, harsher environments, protection against factors such as water, dust, corrosive agents, and emitted radiation are all becoming increasingly common requests.”

Leidig goes on to say that failing to base enclosure design on the operating environment can result in decreased lifespan of the equipment, citing a factory floor as an example.

“I’ve seen enclosures installed in industrial environments, where the fans are sucking in dust and debris, circulating it through the equipment which is leading to premature failure,” says Leidig. “With the addition of a filter at the air intake, they could have avoided this problem. This is a simple example, but one that demonstrates the importance of discussing the operating environment with the enclosure manufacturer.”

What, if any, industry regulations must be met?

In addition to posing new equipment protection concerns, new environments bring new regulatory requirements. Many industries have specific design, manufacturing, and installation processes that must be used in order to meet these regulations.

“Increasingly, enclosure manufacturers must act as regulatory compliance consultants for buyers,” explains Leidig. “I’ve seen situations where our customers have first-rate electrical engineers, but when it comes to meeting the architectural building seismic requirements outlined by the International Building Code (IBC), they’re out of their element.”

Industry regulations are most commonly in place to ensure there are standards of equipment protection based on environment. For instance, the IBC sets forth standards for how enclosures must be installed in areas with seismic concern. The National Electrical Manufacturers Association (NEMA) sets ratings for protection against environmental factors such as water and dust. The Federal Communications Commission (FCC) has set forth guidelines for shielding of radio frequency interference, and the military has a wide array of standards that apply to specific installation scenarios, such as protection against shock and vibration on naval ships.

Meeting these regulations is often a legal necessity for customers; however, it’s not uncommon to see a gap in communication between the buyer and the installer, leading to project delays and increased costs.

“On multiple occasions, we’ve had procurement specialists or systems integrators purchase enclosures without informing us of the necessity for regulatory compliance,” said Leidig. “When they get the product, and the installer or building engineer sees it’s not stamped with the necessary code, they are not allowed to install the enclosure. At that point, they have to ship it back, and we start over again, which delays the project and drives up costs. This further demonstrates the necessity of good communication between the person procuring the equipment and the installer.”

What size enclosure will be a sufficient long-term solution?

Size often seems a relatively easy decision to make based on the number of rack units needed to house all the equipment and accessories, but Leidig stresses that there are a couple of factors that buyers often fail to consider, the most common of which is the possibility of future growth.

“It’s important for a buyer to consider potential future growth before settling on a size. All too often, buyers will buy only for what they need at that particular moment,” says Leidig. “I’ve seen a community college that had a small server room with racks packed to capacity. When the time came to expand, they had to expand into another space, ultimately eliminating a classroom. The ceiling in the server room was such that it would have accommodated much taller racks, so if they had purchased racks with extra rack units to begin with, they probably could have avoided expanding into another room.”

The other factor buyers often fail to consider is the size constraints of building elements, such as service elevators and doorways through which the enclosure will have to pass in order to be installed.

“We’ve actually had to develop enclosures that required a unique modular configuration that allowed for final assembly after passing through the small hatch of a submarine,” says Leidig. “The same concept can be applied to normal data center installations; however, it’s quite common for us to hear from customers who don’t think of size constraints until they realize the enclosure doesn’t fit in the elevator. At that point, they either have to make time-consuming modifications, or ship it back to us and start from square one.”

What is the footprint of the space in which the enclosure will be installed?

Any information that a buyer can provide on the installation room layout can help the manufacturer determine proper enclosure configuration, avoiding costly and time-consuming in-house modifications.

“If a buyer can provide information on the predetermined locations of the a/c supply and cabling in the server room, that will allow us to put the intake locations in the most efficient places,” says Leidig, “but it’s still very common for us to have to give them advice on how to modify the enclosure to accommodate those types of things during or after installation.”

What type of equipment is being installed, and what is the ambient temperature of the operating environment?

These are the two most important questions to help enclosure manufacturers determine airflow design and the selection of all the enclosure components that affect airflow (see figure 3).

 Figure3_Buying the right enclosure depends on having an established design in place 

 Figure 3. Importance of knowing ambient temperature, server waste heat and type of enclosure (size, doors, panels, etc). With this information, the manufacturer can recommend the proper location of the fan. In this instance, the best temperature is achieved by installing the impellor at the top (42U) of the enclosure.

“By knowing the type of servers, we can use the wattage and the fan locations to determine waste heat generation and airflow paths in order to recommend the proper location and type of a/c unit, heat exchanger, or blowers, as well as the right type of enclosure panels and doors—whether they’re solid, louvered, or perforated,” says Leidig. “It’s no secret that airflow efficiency is one of the most important factors in reducing power costs and keeping electronics running smoothly, but this type of information is still not often provided upon initial customer request.”

How will the equipment be serviced, and which areas need to be regularly accessed?

The amount of time a data center manager spends servicing equipment can decrease drastically if the enclosure is designed in such a way that accessibility to key components is easy and efficient.

“If a technician expects to need access to a particular component pretty regularly, it makes sense to include an access panel on the side or back, so that the door doesn’t have to be removed each time,” says Leidig. “As far as cabling goes, having a patch panel can free up space, making service easier.” See figure 4.

 Figure4_Buying the right enclosure depends on having an established design in place

  Figure 4. Improved accessibility through the use of a side panel. Often, a buyer will not provide enough information on the type of equipment being installed, which can lead to serviceable components being difficult and time-consuming to access.

Leidig also stresses the importance of locating the wire pass-through grommets in the most efficient spot, citing a news station as an example of the downfalls of not doing so (see figures 5 and 6).

 Figure5_Buying the right enclosure depends on having an established design in place      Figure6_Buying the right enclosure depends on having an established design in place

 Figure 5. Improper cable routing. Often, buyers will provide too little information on the type of equipment being installed, which can lead to inefficient cabling path design.

Figure 6. Proper cable routing. This is what it looks like when the buyer provides information on the type of equipment, allowing the manufacturer to recommend type of placement of cable management solution.

“Simply informing the manufacturer of the size and voltage of the PDU will help determine the proper location of wire pass throughs. This information is rarely presented, but can drastically decrease the amount of time technicians spend rerouting cable,” says Leidig. “I recently visited a news station that was converting to high definition. The technicians had to reroute about 6,000 cables, and because the holes in the enclosure were not efficiently located, the technician probably spent at least an extra minute on each cable. That doesn’t sound like much, but with 6,000 cables, that equates to an extra 100 hours of labor.”

Bottom Line

Whether due to procurement taking place too early in the design or a lack of communication between purchasing agent and designer, not providing adequate information to an enclosure manufacturer can lead to project delays and increased cost due to inefficient design. With today’s enclosure manufacturers increasingly taking a configure-to-order approach to sales, buying the most efficient enclosure solution is easier than ever—so long as the buyer can answer the seven preceding questions.

 
 
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