EH-90-4 Seismic Life Safety Hazards
ENVIRONMENT, SAFETY & HEALTH
BULLETIN
Assistant Secretary for U.S. Department of Energy
Environment, Safety & Health Washington, D.C. 20585
DOE/EH-0161 Issue No. 90-4 December 1990
Seismic Life Safety Hazards
(Assessment and Responses)
DOE's Oak Ridge Operations Office requested a seismic study of five buildings
housing Federal and DOE-contractor employees at Oak Ridge, TN. The study used
documented Federal (1,2) guidelines and concluded that two of the structures
are "hazardous buildings" (Figure 1), thereby posing a "life safety hazard."
This classification indicates that portions of the buildings could collapse,
their components could fail and fall, and exit and entry routes could be
blocked in the event of an earthquake. Two other structures were found to be
"tentative hazardous buildings." This classification indicates that further
analysis is needed before the buildings are classified as hazardous. The
fifth building studied was found to be potentially "non-hazardous." As a
result of these findings, engineering personnel are conducting an indepth
structural analysis of the buildings to determine necessary corrective
actions, if any.
The Office of Environment, Safety and Health advises building managers at
other DOE sites to understand the seismic life safety hazards of their
buildings and facilities. Knowing the factors that make buildings and other
structures vulnerable to earthquakes is a step in this direction. Use of the
referenced guidelines provides a framework for judging seismic life safety
hazards.
Properties of Hazardous Buildings
Buildings that have the following properties could be subject to considerable
damage in the event of an earthquake:
o The location is in Earthquake Zones 2, 3, or 4 (see Figure 2).
o The building is deteriorating, as indicated by such signs as cracked walls
and warped beams.
o The building structure is overloaded. This can occur when a building houses
more workers than it was designed for or when its use changes (e.g., an old
office building is converted to a storage facility for heavy materials).
o The designer failed to incorporate seismic safeguards. Buildings may be
unsafe even if they are "designed to code." Early building codes often did
not include seismic requirements. Managers should be aware that buildings
constructed prior to 1960 probably do not have seismic safeguards. Even
today, some local building codes do not include seismic safeguards. In
addition, buildings may meet seismic requirements from a "legal" standpoint
but not meet the "intent" of the code.
o The building is constructed of unreinforced masonry. Unreinforced masonry
buildings pose a unique hazard even in moderate earthquakes. Unreinforced
parapets and walls inadequately tied to the floors and roof can topple onto
sidewalks or adjacent buildings.
o The structure has a concrete frame and was constructed using local codes
whose seismic provisions were lacking or not enforced. Some of these
structures are readily damaged by repeated earthquake shaking and can
collapse even in moderate earthquakes. Most DOE sites are located within
seismic zones where moderate earthquakes are expected.
o The building is a "tilt-up" type structure. These buildings have concrete
walls that are precast on the ground and then tilted vertically into place.
They often fail at the connections between walls, floor, and roof.
o The structure has a "soft" first story. Usually, soft stories consist of an
open space with stand-alone columns instead of interior walls that support
the building above. Such spaces are usually used as garages, stores, or
large offices. The first floor does not have enough strength to resist the
horizontal shaking force of the upper parts of the building.
o The general quality of construction is poor.
While these properties indicate that a building could be vulnerable to
earthquake damage, a seismic assessment of the building is necessary. Such
assessments should be performed by structural engineers experienced in seismic
safety.
Nonstructural Hazards
In addition to dangers posed by buildings, personnel at DOE facilities should
be aware of hazards presented by nonstructural elements within buildings.
According to the Seismic Safety Guide 3, these hazards include suspended
ceilings, ducts and piping, mechanical and electrical equipment, elevators,
file cabinets, bookcases, partitions, glazing, architectural ornamentation,
and miscellaneous moveable objects.
The process of finding hazards presented by nonstructural elements begins by
considering what will happen to the contents of a building if it undergoes
violent shaking. Efforts to minimize these hazards should include the
following.
o Situate file cabinets so that the drawers are aimed away from occupants of
the office. Heavy file drawers supported on low-friction bearings could be
ejected during an earthquake if the cabinets do not have latches. Wide,
flat drawers in flat tracing files may also become massive, multiple
missiles when accelerated out of cabinets.
o Properly restrain bookcases, storage shelves, and lockers. In addition to
falling on someone during an earthquake, these objects could topple or
discharge their contents, resulting in cluttered or blocked escape routes
(Figure 3). A height limit should be established (e.g., 5 feet high) to
anchor furniture and equipment. Any objects over the established height
should be braced or bolted into a wall. The wall must provide adequate
strength for anchorage.
Gypsum wall board, for instance, is not strong enough to be used as an anchor.
o Avoid storing heavy objects above work stations.
o Store compounds, liquids, or gases in unbreakable containers; and, if these
elements are incompatible, store them away from each other (Figure 4). In
the event of an earthquake, breakable containers can slide off shelves and
spill their contents, which could mix and explode or give off toxic fumes.
What To Do Before An Earthquake Hits
o Check in your DOE library and review their documents on earthquakes.
o Make sure adequate medical supplies, trained personnel, water, and food are
available at your facility.
o Consider how business will be conducted and emergency information
transmitted at the workplace if phone and power service are limited or wiped
out.
o Check with Federal and state agencies to obtain information on actions to
take at home.
What To Do When An Earthquake Hits
The following actions should be taken in the event of an earthquake.
o Duck under a strong desk or table. Cover your head and face to protect them
from broken glass and falling objects. Hold onto the desk or table, and be
prepared to move with it if it slides on the floor. Hold your position
until the shaking stops. "Duck, Cover, and Hold" practice drills should be
held to familiarize employees with how to react in an earthquake.
o Do not use stairways or elevators during the shaking.
o Do not run outside during the shaking. Many people are killed just outside
of buildings by failing bricks and other debris.
o Move to the shoulder of the road and away from bridges, overpasses, power
lines, and large buildings as quickly as it is safe to do so if you are
driving when an earthquake strikes. Stay in the car, and wait for the
shaking to stop.
1 Guidelines for Identification and Mitigation of Seismically Hazardous
Existing Buildings, NISTIR 80-4062, ICSSC RP-3, NIST, Gaithersburg, MD,
March 1989.
2 ATC-14, Evaluating the Seismic Risk of Existing Buildings, Applied
Technology Council (ATC), Redwood City, CA, 1987.
3 Seismic Safety Guide, Donald G. Eagling, LBL-9143, September 1983.
----------------------------------------------------------------------------
This Bulletin is one in a series of publications issued by EH to share
occupational safety and health information throughout the DOE complex. For
more information, contact Eleanor Crampton, Performance Assessment Division,
Office of Environment, Safety and Health, U.S. Department of Energy,
Washington, DC 20545, telephone FT'S 233-3732, Commercial 301-353-3732.
----------------------------------------------------------------------------