The more servers that are added to a datacenter, the more cooling that center is likely to need. And the more cooling those servers require, the more "whoosh" is generated. Whoosh, for the uninitiated, is the annoying noise of fans and humming power supplies that can feel like a pressure in your head.

Datacenter workers live with this noise. It's part of the job and the culture. But there may be reason to start giving the noise issue more attention: datacenter consolidations and the adoption of high-density equipment -- both big industry trends -- are bringing more equipment and denser and hotter systems into datacenters.

There's a dearth of scientific data assessing noise trends in datacenters, its health consequences, and the impact on productivity. Noise is simply taken for granted by datacenter managers who spend little, if any, time measuring sound levels. For the most part, datacenter workers just learn to deal with it.

"It's pretty loud, it's pretty stressful," said computer operator Bruno Skiba, who works at a financial services firm and wears ear protectors similar to those used on a firing range.

Noise, of course, varies from center to center, system to system. It's now fairly common for datacenter workers to spend a lot of time off the datacenter floor and manage systems in separate rooms. And on a system level, noise can vary. While some racks may have high-speed, whinny fans, some Itanium-based servers from Hewlett-Packard have larger, less noisy fans. Skiba's firm recently got a delivery of those quieter servers.

Taken in concert, the noise generated from all the equipment in a datacenter can be distracting. That fact prompted datacenter workers at C I Host, a Dallas-based hosting company, to get Bose noise-canceling headphones to help make the work environment comfortable, said Christopher Faulkner, CEO at C I Host.

"The noise -- the pressure on their head, if you will -- is very distracting and causes serious issues with [workers] being able to concentrate and do their jobs," said Faulkner.

Faulkner said he's never measured the noise in his datacenter, something that wouldn't be surprising to Tad Davies, executive vice president of the Brick Group, a St. Louis-based company that designs and builds datacenters. Davies said he can recall only one IT manager who asked for sound level measurements. "It's been, universally, an issue that has not been brought up," he said.

Davies, without naming the customer, shared a schematic of the datacenter showing the decibel levels taken in 12 different places in the facility. The lowest was 70 dB and the highest 79 dB. The highest levels were recorded near HVAC equipment. At these levels, you have to talk loudly to be heard, but they are considered safe levels under federal standards.

By comparison normal conversation is about 60 dB; a power lawn mower is about 90 dB, a jet engine at takeoff, 140 dB, according to the National Institute for Occupational Safety and Health (OSHA). The federal government sets workplace standards for noise, and doesn't require action until workers are exposed to average noise levels of 85 dB or greater during an eight-hour day.