Foundation Considerations; How Strong And Rigid - Milnor MWR09E5 Series General Operating And Troubleshooting

Chapter 1. Commissioning
Estimates of the maximum force normally encountered are available for each model and size
upon request. Floor or foundation sizes shown on any Milnor
situations based only on previous experience without implying any warranty, obligation, or
responsibility on our part.

Foundation Considerations

1.2.1.
Size for size, rigid washer-extractors naturally require a stronger, more rigid floor, foundation, or
other supporting structure than flexibly-mounted models. If the supporting soil under the slab is
itself strong and rigid enough and has not subsided to leave the floor slab suspended without
support, on grade installations can often be made directly to an existing floor slab if it has enough
strength and rigidity to safely withstand our published forces without transmitting undue
vibration. If the subsoil has subsided, or if the floor slab itself has insufficient strength and
rigidity, a deeper foundation, poured as to become monolithic with the floor slab, may be
required. Support pilings may even be required if the subsoil itself is "springy" (i.e., if its
resonant frequency is near the operating speed of the machine). Above-grade installations of rigid
machines also require a sufficiently strong and rigid floor or other supporting structure as
described below.

How Strong and Rigid?

1.2.2.
Many building codes in the U.S.A. specify that laundry floors must have a minimum live load
capacity of 150 pounds per square foot (732 kilograms per square meter). However, even
compliance with this or any other standard does not necessarily guarantee sufficient rigidity. In
any event, it is the sole responsibility of the owner/user to assure that the floor and/or any other
supporting structure exceeds not only all applicable building codes, but also that the floor and/or
any other supporting structure for each washer-extractor or group of washer-extractors actually
has sufficient strength and rigidity, plus a reasonable factor of safety for both, to support the
weight of all the fully loaded machine(s) including the weight of the water and goods, and
including the published 360-degree rotating sinusoidal RMS forces that are transmitted by the
machine(s). Moreover, the floor, foundation, or other supporting structure must have sufficient
rigidity (i.e., a natural or resonant frequency many times greater than the machine speed with a
reasonable factor of safety); otherwise, the mentioned 360-degree rotating sinusoidal RMS forces
can be multiplied and magnified many times. It is especially important to consider all potential
vibration problems that might occur due to all possible combinations of forcing frequencies
(rotating speeds) of the machine(s) compared to the natural frequencies of the floor and/or any
other supporting structure(s). A qualified soil and/or structural engineer must be engaged for this
purpose.
PELLERIN MILNOR CORPORATION
®
document are only for on-grade