Each BladeCenter S chassis has four fan modules for cooling and each fan module has 2 fans. The fan modules generate measurable noise.
The sound levels for the BladeCenter S chassis range from 6.3 bels to 6.8 bels depending on the number and type of blade servers that are installed.
The actual sound-pressure levels in your installation depend on a variety of factors, including the number of servers in the installation, the size, materials, and configuration of the room where the servers are installed, the noise levels from other equipment, the room ambient temperature, and employees' location in relation to the equipment.
Your server installation may be subject to government regulations, such as those prescribed by OSHA or European Community Directives, that cover noise-level exposure in the workplace. Consult a qualified person, such as an industrial hygienist, to determine the sound-pressure levels to which your employees are exposed.