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Stanford University Medical Center
Elevator #7 - Heliport
300 Pasteur Drive, Stanford, CA 94305
Contractor:
KONE Inc.
OSHPD Engineer of Record:
Peyvan + Healthcare Design
Alteration of simplex, basement, under-slung, 2:1 roped,
geared traction passenger elevator. This elevator,
installed in 1985, serves a rooftop heliport for Stanford
Life Flight. The project is a control upgrade, which
under the current CCR Title 8 code, must comply with ASME
A17.1-2004, including
ascending car overspeed (ACO) and unintended
car movement (UCM) protection. This is accomplished through the installation of a
Hollister-Whitney Rope Gripper™.
RCB Elevator Consulting, LLC and its associate structural
engineering firm, Eddington Engineering, performed
the elevator and building engineering required. This included performing a field
survey.
Project Description
The
Stanford University Medical Center is a major general
acute care hospital and medical school in Northern
California. Elevator #7 is one of the most critical
elevators on the campus due to its location and service.
It is a simplex elevator, the only one that serves roof
level heliport. The quick and safe transport of
critically ill patients to the emergency rooms, arriving by
helicopter, can make the difference between life and death.
To decrease potential shutdowns and improve reliability
the elevator control systems are being replaced with new,
solid-state logic controls and VVVF-AC motor drive.
The conversion will substantially reduce the number of
control relays and eliminate the motor-generator, all items
that require more maintenance and have a greater potential
for failure than the new solid-state systems.
Additionally, solid-state door equipment with closed loop
feedback will be provided - reducing another common source
of service interruption.
ASME A17.1-2004, 8.7.2.27.5 - Change in Type of Motion
Control requires the addition of
ascending car overspeed (ACO) and unintended
car movement (UCM) protection. Whereas most new
gearless drive machines include a secondary brake to perform
this function, most existing and new geared drive machines
do not. To meet this code requirement, we have
designed the addition of a rope brake.
As the
drawings below show, a
Hollister-Whitney,
Rope Gripper™ model #622 rope
brake is mounted over the basement geared traction drive
machine. A custom structural pedestal frame was
designed to support the rope brake, including the dynamic
loading exerted when the device actuates. The mounting
was designed with full detailing so that the complete unit
could be shop fabricated from the drawings and simply bolted
into place. No field welding was required and only
four holes into the machine base frame need be drilled in
the field. To accomplish this, a very accurate field
survey was requires so as to obtain the necessarily precise
locations and dimensions of the existing equipment.
The
drawings also show the seismic anchorage of the new
controller, which includes vibration and sound isolation.
To obtain true isolation, there must be no contact between
the control enclosure and the structural floor slab.
The common practice of simply adding a strip of rubber or
neoprene under the enclosure base in reality provides no
isolation. The vibration will travel through the steel
anchor, with its washer resting on the enclosure base and/or
the anchor shank in contact with the base. To assure
isolation, we specify and detail pre-fabricated and load
approved isolators as shown. (See our
Equipment Isolation page for additional information.)
As an
OSHPD project, drawings and structural calculations were
prepared and submitted proving the new equipment anchorage
and supports. The other structural elements of this
elevator appeared to meet the
OSHPD requirements as it was installed after the
OSHPD requirements came into force.
In summary, this is a good example of a limited
OSHPD project involving only new controls and a rope
brake. However, great care was taken in preparing the
design to help reduce the field labor and the elevator down
time required for the project. This is the standard approach of RCB Elevator Consulting, LLC working in
conjunction with Eddington Engineering.
Pictures
This picture shows the existing controller and
motor-generator in the foreground and the existing geared
drive machine in the background.
These pictures show the original Schindler Haughton geared
drive machine to which the new Hollister-Whitney Rope
Gripper is to be installed.
Drawings & Engineering
Click on the drawing above to open the full drawing set in
PDF format. Note drawings cannot be printed or altered. All
drawings and artwork are the property of RCB Elevator
Consulting, LLC and may not be used, copied, or in anyway
used without the owner's consent.
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Stanford Medical Center