A generic example of hot and cold airflow and the arrangement of server aisles is shown in  Figure 10-2. As shown in Figure 10-2, rows of servers must be placed front-to-front. Chilled air is provided  through perforated floor panels that are placed in rows between the fronts of servers (the cold  aisles). Perforated tiles generally are not placed in the hot aisles.  Figure 10-2 Hot and cold aisles 10.2 Physical specifications If your computer room causes the temperature in the hot aisles to exceed a comfortable  temperature, add as many perforated tiles as necessary to create a satisfactory comfort level.  Heated exhaust air exits the computer room above the computing equipment. For more information about the requirements for air-cooling options, see  IBM 3907 Installation  Manual for Physical Planning,  GC28-6974. This section describes the weights and dimensions of z14 ZR1 server. The z14 ZR1 is the  first IBM Z server that is based on a 19-inch rack; therefore, dimensions and weights are  significantly different from previous generations of IBM Z servers.  The z14 ZR1 can be installed on a raised or non-raised floor. For more information about  weight distribution and floor loading tables, see the  IBM 3907 Installation Manual for Physical  Planning,  GC28-6974. This data is used with the maximum frame weight, frame width, and  frame depth to calculate the floor loading. Chapter 10. Environmental requirements  347