Corrosion_Form.pdf
PDF 1 MB Posted
- Attached to
- Large Valve Vault Replacement
- Solicitation number
- 107595
- Issued by
- Montgomery County, Maryland
About this file
This is a Corrosion Condition Assessment Report prepared by DACCO SCI, INC. for the Washington Suburban Sanitary Commission (WSSC) regarding two Large Valve Vault Replacement (LVVR) projects in Silver Spring, Montgomery County, Maryland. The assessment evaluates corrosion conditions for projects BT7370A22 and BT7373A22. Project BT7370A22 involves the relocation of a 72-inch and 30-inch water main vault at 1200 W University Boulevard, while project BT7373A22 involves the retrofit of a 24-inch water main vault at 12501 Old Columbia Pike. The corrosion assessment was completed on November 17, 2023, with soil samples collected at nine feet depth from the BT7370A22 location.
DACCO SCI, INC. determined that soil conditions at the BT7370A22 site are moderately corrosive, with a pH of 4.4, redox of 60 mV, chloride concentration of 28 ppm, and soil resistivity of 5,300 ohm-cm. Based on WSSC Common Design Guidelines (2017) Corrosion Control Chart "C," the report recommends that BT7370A22 be designed with PRITEC-coated pipe and a cathodic protection system, including insulating joints for electrical isolation, external bonding for electrical continuity, and IJ-type test stations for monitoring. For BT7373A22, the recommendations specify zinc-coated ductile iron pipe with V-BIO encasement if pipe replacement is required outside the valve vault, with field coating and V-BIO encasement for connections to existing pipes. No pricing, funding sources, or contract award information is provided in this technical assessment document.
View the file
Other files
Show all 22
On GovTribe
Work with this file
- Download the original file
- Contacts named in this file
- Similar government files
- Ask GovTribe AI about this file
Text version
REPORT
PRELIMINARY FIELD OBSERVATIONS
CORROSION CONDITION ASSESSMENT
LARGE VALVE VAULT REPLACEMENT
WSSC JOB NO. BT7370A22 AND BT7373A22
Submitted by
Chester Dacres
DACCO SCI, INC.
10260 Old Columbia Road, Suite A1 Columbia, Maryland 21046
Submitted to
Daniel Savage The Wilson T. Ballard Company
17 Gwynns Mill Court Owings Mills, Maryland 21117
November 17, 2023
DSI-WTBCO-2355
DACCO SCI, INC.
CORROSION ENGINEERING - MATERIALS TECHNOLOGY - ELECTROCHEMISTRY
10260 OLD COLUMBIA ROAD, SUITE A1, COLUMBIA, MARYLAND 21046
BALT. (410) 381-9475 • DC (301) 596-7019 • FAX (410) 381-9643
dacres@daccosci.com www.daccosci.com
DSI
November 17, 2023
Daniel Savage Design Engineer The Wilson T. Ballard Company 17 Gwynns Mill Court Owings Mills, Maryland 21117
RE: PRELIMINARY FIELD OBSERVATIONS – CORROSION CONDITION
ASSESSMENT OF THE LARGE VALVE VAULT REPLACEMENT -
WSSC JOB NOS. BT7370A22 AND BT7373A22
Dear Mr. Savage:
DACCO SCI, INC. has completed the preliminary field observations using the Washington Suburban Sanitary Commission (WSSC) Form "B" Corrosion Documentation for the BT7370A22 and BT7373A22 Large Valve Vault Replacements (LVVR).
A soil sample was collected at a depth of nine (9)-feet from the proposed BT7370A22 location and was found to be moderately corrosive.
In accordance with the WSSC Common Design Guidelines (2017) Corrosion Control Chart “C”, DACCO SCI, INC. recommends that the proposed BT7370A22 LVVR project alignment should be designed with coated pipe and with cathodic protection.
If there are any questions or revisions to the report, please do not hesitate to contact me.
Sincerely, Chester Dacres, Ph.D., P.E.
President
CMD/nb mailto:dacres@daccosci.com
• DACCO SCI, INC. • 10260 Old Columbia Road, Suite A1, Columbia, MD 21046 • (410) 381-9475 • DSI-WTBCO-2355 www.daccosci.com 11/17/2023
TABLE OF CONTENTS
EXECUTIVE SUMMARY
Location of Project
Soil Chemistry Data
RECOMMENDATIONS
FORM "B" CORROSION DOCUMENTATION (BT7370A22)
FORM "B" CORROSION DOCUMENTATION (BT7373A22)
DSI-WTBCO-2355 www.daccosci.com 11/17/2023
EXECUTIVE SUMMARY
Location of Project
Table 1 below summarizes the LVVR projects. Figure 1 and Figure 2 show the alignment of BT7370A22 and BT7373A22, respectively.
Table 1 - Summary of Projects
Project No. Location Size (inch)
Retrofit/Relocation
BT7370A22 1200 W University Blvd, Silver Spring, Montgomery County, Maryland
72/30 Relocation
BT7373A22 12501 Old Columbia Pike, Silver Spring, Montgomery County, Maryland
24 Retrofit
The proposed pipe under BT7370A22 will connect to a 30-inch (Contract 1961-5411) and 72-inch (Contract 1966-2621J) prestressed concrete cylinder pipe water mains.
Figure 1 – Map of the BT7370A22 LVVR
Proposed BT7370A22 Vault
SB-01
Contract
1966-2621J Contract 1961-5411
DSI-WTBCO-2355 www.daccosci.com 11/17/2023
The vault pipe under BT7373A22 will connect to a 24-inch (Contract 1996-1501A) ductile iron pipe water main with polyethylene encasement.
Figure 2 – Map of the BT7373A22 LVVR
Soil Chemistry Data
DACCO SCI, INC. tested one (1) soil sample collected by AB Consultants, Inc. of Lanham, Maryland. The in-situ test was performed in accordance with American Society for Testing and Materials International (ASTM) standards that included pH (ASTM D4972), redox (ASTM G200), and soil resistivity (ASTM G57). Further testing was performed in the DACCO SCI, INC. laboratory to determine the soil’s chloride concentration (ASTM D512). The details of the results are shown below in Table 2.
Table 2 – Soil Chemistry Results
Site Identification pH Redox (mV)
Chloride (ppm)
Soil box Resistivity (ohm-cm) Soil Type
Corrosivity Index
Corrosivity Rating
SB-01 4.4 60 28 5,300 Silt 8.0 Moderate
Proposed BT7373A22 Vault
Contract 1996-1501A
DSI-WTBCO-2355 www.daccosci.com 11/17/2023
RECOMMENDATIONS
DACCO SCI, INC. recommends, per WSSC Corrosion Common Design Guidelines (2017), the following:
1. MV7370A22:
a. Design using PRITEC coated pipe.
b. Install a cathodic protection system.
c. Externally bond pipe segments to ensure electrical continuity.
d. Install Insulating joint (IJ) between the proposed and existing pipes to ensure electrical isolation of the alignment with WSSC Standard Detail C/3.3 and C/3.4.
Field coat the connection for five (5)-feet on to the proposed pipe.
e. Install an IJ type test station to monitor the IJ’s effectiveness at each IJ.
2. MV7373A22:
No pipe replacement is expected outside of the proposed valve vault. If pipe replacement is required outside of the valve vault, design using zinc-coated ductile iron pipe (DIP) with V-BIO encasement. Additionally, connections to existing DIP should be field coated five (5)-feet on either side of the connection and V-BIO encased.
The WSSC Forms "B" Corrosion Documentation are shown below.
FORM "B"
Corrosion Documentation
1. Job Description:
2. Site Evaluation
a) Existing Pipe Analysis:
b) Stray Current Analysis:
c) Soil Condition Analysis:
3. Corrosion Control Requirements (based on results of Stray Current Analysis and Soil Condition Analysis):
11/08/2023
BT7370A22 Silver Spring, Montgomery M5286F05
X 30,72-inch
X X X X Water Valve
30,72-inch
X
X
X
Insulate and field coat, see standard detail C/3.3 and C/3.4
SB-01 8 Moderate
X
FORM "B"
Corrosion Documentation
1. Job Description:
2. Site Evaluation
a) Existing Pipe Analysis:
b) Stray Current Analysis:
c) Soil Condition Analysis:
3. Corrosion Control Requirements (based on results of Stray Current Analysis and Soil Condition Analysis):
11/08/2023
BT7373A22 Silver Spring, Montgomery M5167F10
X
X 24-inch
X Water Valve
24-inch
X
X
Field coat 5' on each side of connection and encase the connection in V-Bio
X
| EXECUTIVE SUMMARY |
| Location of Project |
| Soil Chemistry Data |
| RECOMMENDATIONS |
| Form "B" Corrosion Documentation (BT7370A22) |
| Form "B" Corrosion Documentation (BT7373A22) |
File details come from the government source that posted it. Updated .