Chapter 3 Installation Guidelines
14
As you can see from the illustration on the right, 1.25 m racks are “unconditionally” stable, and
1.6 m racks are very difficult to overload, as they extend only 1 U above the critical height.
For 1.6 m and 1.96 m racks, add the weights of the units which have centers of gravity above 32
U, then compare the sum of the weights below 32 U. Always configure racks for the majority of
the weight below the critical height.
Assumptions / Disclaimers
The center of gravity for the racks is found in the geometric center. Centers of gravity of
products is assumed to be at their Front/Back, Left/Right centers. Grossly imbalanced equipment
will void the calculations. If doubt exists, stability should be verified by tip-over testing, per UL-
1950, SECTION 4.1.
Slide-Mounted Products
Slide-mounted products and work surface/keyboard products need weight and balance
calculations performed to determine the need for ballast to reduce the risk of cabinet instability.
The worksheets for both are provided on the following page. If both slide-mounted and work
surface/keyboard products are being used, calculate both and add the results.
To reduce the risk of rack instability when operator serviceable, slide-mounted products are
installed, use the following worksheet to determine the need for additional counterweight ballast.
If there are no operator serviceable, slide-mounted products in the rack, this worksheet can be
ignored.
An operator serviceable, slide mounted product is defined as any product which can be extended
from the rack for servicing without requiring the use of any tool. A product requiring the use of a
tool to facilitate servicing or extending the product is the definition of trained service personnel
serviceable only. When a trained service personnel serviceable only product is extended, the use
of the anti-tip mechanism is required, but counterweight ballast is not. See Figure 3-5.
Also note that some HP products preclude the use of counter weight, due to their mounting
depth. These products are appropriately labeled, and require that the rack anti-tip mechanism
used before the slider product is pulled out. Also, it is recommended that no more than one slider
product be pulled out at one time, to ensure the greatest possible stability.
NOTE No slider products may be withdrawn or extended at the same time the work
surface is in use.
To Next Page
Loading...
