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By Robin Ringler, PE
Community art centers often pop up in quaint old
buildings and quickly become local treasures, but being a treasure rarely
puts enough in the treasury for that proverbial rainy day. When frequent
floods hit that quaint old building, though, your community treasure could
go under – financially as well as physically.
That was the challenge facing the Center for Creative Arts (CCArts) in
Yorklyn, Delaware, a historic snuff mill town outside Wilmington. Operating
in a decommissioned elementary school since ’81, the center houses a vibrant
mix of visual and performing arts activities for residents of all ages and
serves an area extending from Wilmington to Pennsylvania’s Brandywine
Valley.
In The Line Of Fire
Trouble is, CCArts in its present location gets more than its share of
floods but can’t afford to relocate. Sitting on a riverine flood plain, the
center has been hammered by floods after major hurricanes and suffers minor
soakings several times a year. “Whenever a big rain hits the Brandywine or
Susquehanna valleys, flash floodwaters invade the building with only two
hours’ warning,” says director Willard Crichton. “Recovery can take days or
weeks. And can you ever really replace a retiree’s first painting or a
youngster’s first paper sculpture?”
Public flood advisories and warnings are too frequent to be useful. Most
don’t correlate to conditions at CCArts’ particular site, and turn out to be
false alarms. By contrast, even a little rain in one spot in Pennsylvania,
which doesn’t trigger a local flood advisory, can transform a gentle stream
adjoining the property into a torrent. “If we evacuated with every public
flood advisory, we’d have to shut down for good,” says Crichton. “We just
watch the road. When water crosses it, it’s time to move out the people and
cars and button the place down.”
Each real flood also upsets the schedule for plays, exhibits and special
events. Logistics aside, enthusiasm naturally dampens with each soaking,
despite everybody’s best efforts.
Flooding got so bad after Hurricane Hugo in 1999 that the CCArts board
looked seriously into relocating, but the $25 million price tag forced them
into Plan B. That hurricane flooded out the basement and two lower-level
studios, put the main level six inches underwater, shut the place down for
two weeks and cost $125,000 to clean up. Plan B, begun in 2001, involved
renovating the existing building and floodproofing for one tenth the budget
as relocating. They brought in Anderson Brown Higley Associates (ABHA),
Wilmington to make it happen.
Location, Location, Location
The building, a converted ‘30s era elementary school with a couple of
additions over the years, sits on a slope and is essentially bi-level.
Elevation of the two interior levels is within one foot – either way -- of
the FEMA 100-year flood level. When it was built, FEMA didn’t even exist.
The center’s front entrance slab is about two feet higher than the
classroom/studio slab. A basement with mechanical room and two more activity
rooms lies under a portion of the classroom/ studios. Underneath the rest is
crawl space. Habitable space, totaling about 20,000 square feet, is spread
among 11 studios and class/activity rooms.
Many foundation vents led to easy flooding of the crawl space and basement.
Nine doors provide access to various parts of the building. One below-grade
entrance to the lower level studios has collapsed three times due to water
head pressures during flood conditions.
FEMA recommends flood proofing to a level one foot above the 100 year flood
plain level. New Castle County in Delaware adds another six inches to the
FEMA number. This means that the building should be flood proofed to a level
2.5 feet above the main floor, which for all practical purposes is also the
window sill level in most of the building.
Three Step Solution
To flood-proof the building to that 30-inch level while minimizing costs,
CCArts used four ideas: (1) Permanently brick up 14 vents, (2) permanently
decommission and seal three doors including the outside entrance to the
lower-level studios, (3) temporarily decommission and seal one door, and (3)
protect four grade-level openings with a variety of Presray Flood Barriers.
“Luckily the main entrance area is above the 100-year flood level so it was
safe as-is,” architect Peter Anderson explained. “This reduced floodproofing
costs considerably.”
Barrier Selection Issues
Choice of flood barrier type for the secondary openings was governed by four
key factors: speed of deployment, installed cost, available swing room and
ease of use. Since none of them are in high-traffic or appearance-sensitive
areas, frames and tracks for the flood barriers could be raised and visible.
Lift-out barriers would be most economical, but take time, some strength and
training to deploy. The situation here is sudden flood threat to a building,
so any teacher, volunteer, office worker or member may have to close the
flood gates. There is no permanent custodial staff. After discussions among
CCArts, ABHA and Presray about past experience and realistic future
scenarios, the consensus standard was that all flood doors be operable by an
80-year-old woman alone in the building late at night. To preserve exterior
appearance, all flood doors are inside the building.
Flood Doors, Close-Up
The Presray type FB44 side-hinged door comes with redundant inflatable seals
and self-contained nitrogen inflation system that’s as easy to operate as a
propane backyard barbecue. To close it, you simply release the door from a
dead bolt that holds it out of the way in normal times, and latch it in
place – just like a regular door. Then you open a valve, turn a
three-position switch to “INFLATE”, then “HOLD” and throw one switch. This
pressurizes the main seal. Repeat the sequence with a second switch, and the
backup seal is inflated. Clear directions are printed on the door.
To deploy the sliding door, the operator removes three covers concealing the
frame and track, slides the door across the opening on its track and latches
it in place. Turning the latch handles draws the door into place to complete
the seal. It takes just about five minutes for one person to close all four
flood doors.
One-Piece Seals Make The Difference
The rubber compression on the one-piece molded seals creates a watertight
barrier by maintaining sealing pressure and not taking a set after long-term
compression or storage. One-piece construction eliminates leaks at the
corners, where straight runs of extruded seals would require a miter joint.
The inflatable seals have a layer of fabric reinforcement, similar to a
truck tire, which adds strength, durability and ultimately reliability.
Serendipity
Ironically, a bad flood interrupted early renovation work, but turned out to
be a blessing. Three weeks into this renovation in September 2003, the
remnants of Hurricane Henri caused CCArts’ worst flood, with water in the
main building reaching 5.5 feet above main floor level. This storm has
apparently been classified as a 1-in-500-year occurrence. As a result, a
grant from FEMA helped pay for the work.
The bricked-up openings, including vents, a sunken staircase leading from
the basement and some windows with low sills, will remain closed off
permanently. For now, one other secondary entrance is simply temporarily
decommissioned and sealed as an economy measure. Budget permitting, future
plans call for its recommission with protection from a third side-hinged
door.
Robin Ringler, PE, has
been involved with a number of flood protection projects on new and existing
buildings as an application engineer for Presray Critical Containment
Solutions in Wassaic, New York. |
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