1d. Specs for Murray Hill Water Tower 1 . . CITY OF
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,� 690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
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.fit. (612) 937-1900 • FAX (612) 937-5739 k� �;� ,Admintstrs(�
Iindorsed "
II MEMORANDUM Modified _..'
laijscted
TO: Don Ashworth, City Manager Date Sub111;7;.;! to Commission
I FROM: Gary Warren, City Engineer .
pie s, Council
DATE: May 31, 1990 __._.___4"1 a
ISUBJ: Approved Revised Specificat s for Murray Hill Water
Tower Rehabilitation and Painting
Project No. 89-24; Authorize Advertising for Bids
I
As a result of recent public concerns relative to lead toxicity,
I the Minnesota Pollution Control Agency (MPCA) has issued the
attached Advisory Notice concerning suggested precautions and
measures to be taken for sandblasting of elevated water storage
I tanks. Staff received this information after the City had
already advertised this project for bids.
In response to this advisory, a sample portion of the exterior of
II the Murray Hill water tower was sandblasted and samples analyzed
to determine the lead content of the paint and primer. The
results showed the paint content when mixed with the blasting
II compound has a concentration of three parts per million. As a
point-of-reference, the "red" lead primer used on many State
bridge structures and the like, typically has a lead content of
I 58 parts per million. A water tower in Chaska which was recently
sampled had a content of 14 parts per million. Although the
Murray Hill water tower is definitely on the very low side as far
as lead content, the MPCA advisory at this time appears to have
I consessions for low level concentrations. The City, therefore,
would need to incorporate very expensive collection techniques
into the rehabilitation specifications in order to blast and
I repaint the exterior of the Murray Hill water tower tank at this
time.
While it would be desirable to have the exterior of this tank
I recoated, the financial impact and potential liability for the
City at this time does not appear reasonable. It, therefore,
made better sense to revise the specifications for rehabilitation
I of the Murray Hill water tower to reflect recoating of the
interior of the tank only since this can be accomplished in a
closed environment.
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I . .
Don Ashworth
May 31 , 1990
Page 2
The attached revised specifications dated March 16, 1990, have
been prepared to delete sandblasting of the exterior of the tank
and instead, provide for an exterior washing of the tank to
' remove the obvious dirt and mildew. Staff and our consultants
believe that this is the most prudent/cost effective position to
take at this time .
It is anticipated that in the next two to five years , hopefully
the regulatory requirements relating to lead will become more
manageable and/or the construction techniques for dealing with
' the containment of the blasting sand will be come more practical
such that the exterior of the tank can be refurbished as
originally planned.
' It is, therefore, recommended that the attached revised specifi-
cations for the Murray Hill water tower rehabilitation and
' painting be approved and authorized for bids .
jms
' Attachments: 1. MPCA Lead Advisory
2 . Revised Specifications Exerpts
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Minnesota Pollution Control gency I
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520 Lafayette Road, Saint Paul, Minnesota 55155 ./ r 0
COleri Telephone (612) 296-6300
March 15, 1990 I
t
Dear Mayor:
This letter, to the mayors of all cities in Minnesota, advises you of a problem
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that could affect the environment and the public health of your municipality.
Steel bridges and water towers are large structures that may bear significant
quantities of lead paint. Lead is harmful to both human health and the II environment. Special care is necessary when these coatings are removed as these
structures are repainted. There are Minnesota rules and statutes that presently
apply to this activity. The Minnesota Pollution Control Agency (MPCA) has
developed recommendations for the contained removal of lead paint from these
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structures (see enclosed). We believe these provisions will be effective in
preventing violations of present regulations and in protecting the environment
and the public health from the effects of lead contamination.
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Bridge paints may contain lead in both the primer and the top coat. Larger
structures may bear thousands of pounds of lead. The MPCA has been working with
the Minnesota Department of Transportation to develop effective provisions for II pollution control on state and federal highway bridges. We are providing the
cities with similar provisions in shortened form. Additional information about
these procedures is available to city staff or contractors upon request. II
Iii..,Water towers are frequently sited in residential or public use areas. It is
very important to determine the paint constituents of the coatings and the need I
for containment before any abrasive blasting is conducted. We recommend that
Ailmunicipalities adopt the enclosed pollution control provisions for .the
maintenance of water towers that bear lead in concentrations greater than 1%
(10,000 ppm) and include these as specifications in contracts for repainting. II City or county public health or environmental health staff may specify
additional measures to protect the public health.
If the bridge or the water tower does not have lead-based paint, but it is sited
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near residential or commercial property or school buildings, we advise you to
apply containment during abrasive blasting or to use a non-silica abrasive to
prevent nuisance dust conditions and exposure to silica dust. Under no II circumstances should any lead-based paint be applied to any new bridge or water
tower or to any structure that is repainted.
To request copies of state regulations or for general information, contact II Susan Brustman at 612/296-7769. For more technical information about
sandblasting of bridges or water towers, contact Gordon Anderson at
612/296-7667.
Sincerely CITY OF CHANHASSEN
. Michael Valentine
MAR 26 1990 I
Di rector ENGINEERING DEPT.
Division of Air Quality
NMV:mmr7.29
Enclosures Regional Offices: Duluth•Brainerd•Detroit Lakes•Marshall•Roc I
Equal Opportunity Employer Printed Rochester
on Recycled Paper
I
CITY OF WHAM
SEER)
MAR 261990
IIRecommendations for Pollution Control of Abrasive Blasting
of Lead-Painted Water er8 ENGINEERING DEPT.
IIIdentification of Lead in Paint
I In some cases lead in paint information can be obtained by a careful review of
paint history documents. It may be necessary to contact the paint manufacturer
to determine the presence and concentration of lead in the paint. If there is
no record, then it is necessary to submit a paint sample(s) for laboratory
I analysis for "total lead." It is important that the samples be representative
of all surfaces to be repainted and that the samples include at least as much
primer paint as topcoat.
IIContract Conditions
A method of paint removal and/or of pollution control that provides a measure of
I containment of equivalent or greater efficiency than those described here is
acceptable.
IA. Dry Abrasive Blasting
The following pollution control methods should be applied to prevent
dispersal of lead paint particles when dry abrasive blasting is used.
I1) Conduct abrasive blasting only in low or zero windspeed conditions
such that the containment (below) is effective in preventing dispersal
of paint particles.
2) Suspend a curtain(s) at all times on the downwind side of the water
tower in a manner to effectively contain the paint particles. The
I curtain must be at least as long as twice the height of the bowl.
If the water tower is less than 120 feet in height, then the width of
the curtain must be greater than the diameter of the bowl. If the
I water tower is greater than 120 feet in height, then the width of the
curtain must be greater than half the circumference of the bowl.
If the water tank is a standpipe, then the length of the curtain must
II be greater than two thirds the height of the tank and the width of the
curtain must be greater than half the circumference of the tank.
I At all times, adequate space must be maintained between the curtain
and the metal surface of the tank to contain the dust particles.
The curtain must be separated from the metal surface when paint is
removed on the upper half of a tank that is a sphere.
I3) When paint is removed from any surface above the curtain(s), power
tools (but not sanding tools) must be used to remove all the paint
I followed by dry abrasive blasting (if necessary) with a low-dust
abrasive, or, wet abrasive blasting must be used to remove all the
paint followed by dry abrasive blasting with a low-dust abrasive.
I 4) Lay ground covers at all times on the downwind side of the tower both
inside and outside the curtain(s) to prevent deposition on the soil.
The ground directly beneath the water tower must be covered at all
times. Ground cover must extend a minimum distance of two thirds the
I height of the tower measured from the center column outward.
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'If the water tank is a standpipe, the ground cover must extend.a
minimum distance of one half the height of the tank. I
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. _� a'he width of the ground cover must increase with distance from the
center column and be equal to the area within an angle of 120* except
that the width of this area shall always be greater than the width of
the curtain(s). The ground covers must overlap by 1 1/2 feet.
5) A daily cleanup of all visible deposits of waste material not contained
on the ground cover is necessary following abrasive blasting. This
material must be recovered and not redistributed. Vacuum removal
with filtration that removes small particles is an acceptable method
whereas air pressure or water streams are not acceptable.
B. Alternative Methods of Removal
Because of the height of these structures and the increased air movement '
at these heights, it is difficult to adequately contain the paint particles
by use of dry abrasive blasting with either an impervious or a fine-mesh
curtain. To conduct paint removal only during very low windspeeds will
increase the time necessary to complete the project. Therefore
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a) if the water tower bears paint with a total lead concentration greater
than 5% (50,000 ppm) and it is sited within 300 ft of residential
property or school buildings, or within 200 ft of commercial property or
a public use area*, or
b) if the water tower bears paint with a total lead concentration less
than 5% (50,000 ppm) but greater than 1% (10,000 ppm) and it is sited
within 200 ft of residential property or school buildings, or within
100 ft of commercial property or a public use area*,
then one or more of the following methods should be considered as an
alternative to dry abrasive blasting with containment (as described '
above):
1) wet abrasive blasting in low wind speed with impermeable ground
cover to remove all the paint followed by dry abrasive blasting in
low wind speed with a low-dust, non-silica abrasive
2) power tool (but not sanding tool) removal of all paint in low wind
speed with impermeable ground cover followed by dry abrasive
blasting (if necessary) in low wind speed with a low-dust, non-
silica abrasive
3) dry abrasive blasting of the water tank within a total enclosure
of impervious tarps on scaffolding and with impermeable ground cover
with or without negative pressure, or, dry abrasive blasting
within a total enclosure of fine-mesh curtains on scaffolding and
with impermeable ground cover with negative pressure
4) vacuum blasting (with containment if necessary to prevent ,
contamination)
5) dry abrasive blasting inside a mobile enclosure unit of impervious
material under negative pressure and with a funnel and duct to the
ground, with or without a recyclable abrasive
*public use area includes a public building, recreational area, or '
parking lot
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CITY OF CH NHASSEN MINNESOTA
1 PROJECT # 89-24
1 SPECIFICATIONS FOR INTERIOR CLEANING,
REPAIRING & PAINTING
I. 200 MG SINGLE PEDESTAL SPHEROID
MURRAY HILL TOWER
I REPLACES SPECIFICATION DATED
1 MARCH 16,1990
I
1
III
BY
1 AEC-ENGINEERS&DESIGNERS
511, 11TH AVENUE SOUTH
I
1 MINNEAPOLIS, MINNESOTA 55415
TELEPHONE 612-332-8905
I
1
II hereby certify that this plan, specification
1 or report was prepared by me or under my direct
supervision and that I am a duly Registered R. .
IProfessional Engineer under the laws of the 0 ...: a(r,
1 State of Minnesota �•;• i l 3 S•;{
a RE615TcF.cC
1
� ` INGINE5R 3
del:: Buzek, - •• or
egistration No. 11718 Dated: l5 , 1990 ��NA ESO.,,
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1 BID DATE: May 229 11990
2:00
1 AEC File No. NN 901
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1.0 DESCRIPTION OF PROJECT
1.1 This contract involves the cleaning, coating and repairing of
the 200 MG Single Pedestal Spheroid located at 2230 Melody Hill
Road (behind Minnetonka West Jr. High School) , owned by the City
of Chanhassen, "MN.
The inspection report describing the present condition of the tank
is in Appendix A including photographs of tank condition and
I details-
' The tank modification drawings are in Appendix B.
The surface preparation requirements which must be followed for
all welding and grinding work are in Appendix C.
Included in this contract are the following:
1.2 Structural Repairs and Modifications
1.2.1 The following Repairs and Modifications are required - Bid
item No. 1.
1) Weld the interior seams of the existing two (2) roof I
manways and the one (1) 3 x 3 foot erection plate. See
Appendix A: photos 2, 3 and Appendix B: Tank Drawing sheet
No. 1.
2) Seal weld the eight (8) partially unwelded vertical seams,
(approximately 16 lineal feet) on the shell torus section.
See Appendix A.: photo 4 and Appendix B: Tank Drawing sheet
No. 2.
3) Remove the eight (8) erection angles by air arc gouging,
cutting torch or grinding. See Appendix A: photos 5 and 6.
Repair shell plate by welding and grinding per Appendix D.
. 4) Seal weld on the interior of the reservoir the bottom
seams of the four (4) stiffener ring on the access tube.
See Appendix A: photo No. 7 and Appendix B: Tank Drawings
Sheet No. 3. '
5) Remove the interior reservoir ladder located on the dry
well tube by air arc gouging, cutting torch or grinding.
See Appendix A: photos 2 and 8. Repair shell plate by
welding and grinding per Appendix C.
6) Replace the gasket on the 18 inch round manway on the
bottom of the access tube as specified in Section 8.4.
7) Install a "T" handle to the drain plug in the bottom of
the reservoir. See Tank Drawings Sheet No. 4.
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8) Modify the existing manway/vent. See Tank Drawing sheet
No. 5.
9) Install a new 24 inch diameter, mushroom style screened
roof vent assembly, similar to AEC Standard Drawing or
' equivalent. See Tank Drawings, Sheet 6.
10) Replace the overflow pipe screen assemblies to prevent
access into the reservoir. Use a corrosion resistant,
' heavy-gauge screen with a mesh size no smaller than 1/4
inch square opening.
' 12) Repair by welding the damaged anchor bolt chair. See
Appendix A: photo No. 18 and Appendix C.
' 13) Install an dry well tube support assembly. See Appendix A:
photo No. 8 and Appendix B: Tank Drawing sheet No. 7.
' 1.3 Surface Repairs
1.3.1 The following Surface Repairs are required - Bid item
' No. 2.
1) All erection scab marks (approximately 100) shall be
repaired by grinding and/or welding. All weld splatter
shall be removed by grinding. See Appendix C - Surface
Preparation Requirements.
2) For bidding purposes it is estimated that there are
approximately 48 man/hours to perform the work. This work
will be monitored and verified by the Engineer in the
' filed. Increases or decreases in the amount of the work
and the appropriate contract price adjustments, will be
made per Section GC-22 Modifications.
' 1.4 Interior Wet Sandblast and Recoating
' 1.4.1 Complete Interior Wet Surface - Bid item Mo. 3.
1) Blast entire interior to a SSPC-SP-10-85 Near White Metal
blast.
' 2) Apply two coats of polyamide epoxy as specified in section
8.1 of this specification.
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. er'or •ot ie•a - , . . ,, . - _
gecoating ' " - ' •
1.5.1 Complete Interior Dry - Bid item No. A.
1) . Blast entire dry riser interior, dry well tube, ladders, '
exterior reservoir bowl, conduit, safety cage, overflow
pipe, platforms, exterior of the inlet/outlet pipe, Valve
pit piping and misc. items etc. , to a SSPC-SP-6-85
Commercial Blast.
2) Apply an epoxy coating system on the interior dry surfaces
as specified in Section 8.2.2.
1.5.2 Spot Repair of Exterior Coating - included in Bid item No.
4.
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1) Clean exterior surfaces of the tank damaged during
structural repairs or modifications specified in Section
1.2. Cleaning to conform to the requirements of SSPC-SP-2- I
85: Hand Tool Cleaning.
2) Apply an alkyd coating system on the repaired areas in
conformance with Section 8.2.1.
1.6 Insulated Inlet/Outlet Pipe
1.6.1 Insulated Inset/Outlet piping - included in Bid item No.
4, Section 1.5.3
1) Carefully remove insulation from exterior of the
inlet/outlet pipe. ,
2) Pack insulation in suitable cardboard containers for
storage by the Owner during reconditioning.
3) Blast the inlet/outlet pipe exterior includin
piping) to a SSPC-Sp-6-85 Commercial Blast. g valve pit
4) Apply an epoxy coating system as specified in Section
8.2.2 of this Specification.
5) Reinstall insulation on the inlet/outlet pipe.
6) Contractor to replace damaged insulation' covering and
banding caused by his work.
1 ran--U and Tank iii ing
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1) Clean-up and sterilizing tank per section 10.0 and 17.0.
Although this is not a separate bid item, it is part of
the bidder's scope of work on this project.
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