WA9903-CS000522 (2)RONALD V. CONWAY, P.E.
JOHN W. BIRKHOFF, P.E.
JOE R. CARTER, P.E.
GARY C. HENDRICKS, P.E.
PAUL A. CARLINE, P.E.
MATT HICKEY, P.E.
ROSS L. JACOBS, P.E.
I. C. F1NKLEA, P.E.
JOHN R. BAUMGARTNER, P.E.
SHIMEK, JACOBS & FINK!EA, L.L.P.
CONSULTING ENGINEERS
8333 Douglas Avenue, #820 Dallas, Texas 75225-5816 Fax (214) 361-0204
'
Transmitted via Fa~csim~i~
Phone(214)361-7900
Mr. Steve Dake
Architectural Utilities, Inc., dba AUI General Contractors
300 W. Ramsey
Fort Worth, Texas 76110
Re: City of Coppell
Addition of Pump Number 4 at the Village Parkway Pump Station
Dear Mr. Dake:
You have recently made us aware of the isolation valve situation on the Addition of Pump Number 4 to the
Village Parkway Pump Station project. Based on our discussion with you, we understand the 20-inch
butterfly valve on the discharge side of Pump Number 4 and the 30-inch butterfly valve on the suction side of
the same pump will not fully open. You indicated that is caused by the pump station piping which is
constructed of steel pipe with a cement mortar lining. Steel pipe diameters less than 30 inches are normally
specified using the outside diameter of the pipe rather than the inside diameter. With the addition of the
cement mortar lining to the pipe, the butterfly valve disk cannot be rotated to the fully opened position.
In you letter to us dated May 22, 2000, you indicated the same problems exists on the recently installed 24-
inch butterfly valves on Pumps 1, 2 and 3. However, at this stage we understand these valves were "forced"
to a fully open position by City staff.
On the 20-inch and 30-inch valves, we recommend the spool pieces on the pump side of the valves (pipe
pieces O and P on plan sheet C4, or piece numbers 102 and 107 on the shop drawing submittal) be removed
and the cement mortar lining be chipped away the minimum distance necessary to clear the valve. The
disturbed areas inside the pipe are to be coated and fully cured with two coats of Tnemec 140 Pota-Pox, or
approved equal.
On the 24-inch butterfly valve, since these have now fully open, we recommend they be tested for leakage
across the valve. We suggest each valve be closed one at a time along with the suction side valve. Remove
the pressure gauge on the pump discharge piping and check for water flow out of the pressure gauge tap. If
the any of the valves are leaking, we recommend the repairs be postponed until the off-peak water demand
season late this next fall.
j:\clerical\coppell\1999-153\letters\consfik\isolation valves.doc
Mr. Steve Dake
Architectural Utilities, Inc., dba AUI General Contractors
May 22, 2000
Page Number 2
Please proceed with modifications to the piping for Pump Number 4 at your earliest convenience and provide
us with your revised schedule for the completion of the project.
CC:
1Vk e~rt Hollowell, P.E.
~rry Davis