DIVER INSPECTION REPORT Canyon South, Raw Water Tank

Transcription

1 City of Glenwood Springs 101 West 8th Street, Glenwood Springs, CO DIVER INSPECTION REPORT Canyon South, Raw Water Tank ,000 Gallon on-grade WELDED STEEL RESERVOIR Summary of Contents: Written Report with Recommendations Repair Cost Estimates Engineer s Report Diver Inspection DVD Photo CD 2948 E Badger Way, New Harmony UT

2 INSPECTION REPORT Canyon South Tank 250,000 Gallon On-Grade Welded Steel Dimensions: 36 Dia. x 38 H Inspection Date: Section A-1: General An inspection and cleaning of the ground level water tank known as Canyon South, in Glenwood Springs, CO, was conducted by Advanced Diving Services Inc. on October 23, 2012 according to purchase order# A The inspection was conducted by certified dive personnel. A DVD is included with this report to provide video documentation of the inspection and cleaning work completed. Sec. A-1.1 Scope Every steel water storage tank, standpipe, or reservoir should be carefully inspected prior to repair and/or repainting and at any time when leakage or some other apparent deterioration is observed. In any event, all water tanks should be thoroughly inspected at intervals of not more than five years (American Water Works Association, M , p 132). Sec. A-1.2 Inspection Service Advanced Diving Services Incorporated (ADS) began commercially inspecting water storage tanks in April, ADS is certified in Commercial Diving, Offshore Safety & Survival, Red Cross CPR and First Aid, Hazardous Materials Incident, Response Operations, YMCA Advanced Scuba, Liquid Penetrant - Levels I & II, Magnetic Particle - Levels I & II, Ultrasonic - Levels I & II, Rope Access Technician - Level I, Chevron Riggers Endorsement and Nuclear Quality Assurance. ADS adhere to American Water Works Association standards for inspecting and repairing water tanks, AWWA D All Dive Maintenance Technicians and associated in-tank equipment are fully disinfected according to AWWA Standard C before entering potable water. All ADS operations pertaining to Diving and Confined Space, conducted on your system are in compliance with all applicable OSHA, AWWA, and ADCI standards, procedures, and regulations (including thru ). All inspection personnel are fully qualified commercial dive maintenance technicians certified in ASNT Non-Destructive testing. All of our repair, sealing and coating materials meet or exceed NSF 60 & 61 standards. Sec. A-1.3 Responsibility Advanced Diving Services (ADS), is fully licensed and insured to provide commercial diving services. ADS carries property damage and liability insurance with a combined single limit per occurrence of $1,000,000, aggregate $2,000,000. ADS reasonably protects the tank/reservoir owner/agent against claims arising out of the inspection or cleaning work we provide. Sec. A-1.4 Draining of Tank During inspection and or cleaning, reservoir water levels must be kept at or near full capacity unless noted otherwise. On the date of inspection water level was near full capacity. Sec. A-1.5 Work Included Inspections include field examination of the tank exterior and a full color video report of the tank interior conducted by certified dive personnel. Inspection work does not include repairs, except that, if vent screens, cotter pins or nut pins are found to be missing, they may be replaced at once, or reported promptly to the tank/reservoir owner/agent for replacement. On the day of inspection ADS found no immediately reportable repairs. 2

3 Section A-2: Executive Report Summary Sec. A-2.1 Condition of Paint Exterior Paint The exterior paint on tank walls is in excellent condition with no pull-away during testing. Roof paint is thin as primer is visible. Interior Walls Interior tank walls are in excellent condition. Interior Columns The center column is in excellent condition. Interior Ceiling Paint The ceiling coating is in excellent condition. Tank Floor The tank floor was covered with heavy debris and sediment, 18 average depth. The loose sediment was removed from the tank by ADS at the time of inspection. The floor is in excellent condition. Sec. A-2.2 Pitting There was no measurable pitting observed on the interior walls and the floor during the inspection. Sec. A-2.3 General Tank Condition Cathodic Protection There was no cathodic protection present. Water Condition There were heavy particulates in the water. Water visibility was fair. No oil was found on the surface. Interior Plumbing The interior inlet, outlet and overflow were in excellent condition. Interior Ladder The interior ladder was in good condition. Sec. A-2.5 Recommendations 1. Inspect intake vault/screen and repair as needed. There was heavy debris on the floor of the tank. Reservoir supply intake screen may be missing or damaged. Water bottles were found in the tank need to check and secure manhole covers. 2. Install (2) additional 6-8 vents. The roof vent on this tank is small with respect to the size of the tank. NFPA requires a gross vent area 1 1/2 times the cross sectional area of the discharge pipe(s) or fill pipe, whichever is greater. Undersized vents risk tank structural integrity, and tank outflow capacity. It also contributes to the deterioration of the tank ceiling. Water condensation was present on the tank above the waterline and contributes to the corrosion of the ceiling structure. 3. Minor epoxy repairs to interior of tank. Estimate 1/2 day repair work. Work can be done while tank is full and online. 4. Add a 7 protective fence around the perimeter of the tank for safety and security. 5. Paint exterior roof. Paint is thin and primer is showing through. 6. Tank cleaning is recommended every year (until sediment/debris resolved). Sec. A-2.4 Repair Work Performed Cleaning/removal of sediment and loose floor debris were performed. No other repairs provided at time of inspection. 3

4 (#1) Out Building: No Protective Fence (#3) Out building Plumbing (#4) Exterior Foundation (#2) Exterior Cage Ladder (#5) Exterior Overflow Pipe 4

5 (#7) Roof Access Hatch (#11) Roof Primer (#8) Thin Roof Paint (#12) Roof Vent (#9) Peeling Roof Paint (#13) Roof Vent Screen

6 (#14) Interior Ceiling (#19) Center Column Base (#17) Interior ceiling (#20) Quadrant 3 Manway (#18) Outlet (#21) Quadrant 4 Manway 6

7 (#22) Overflow Box (#25) Wall Section 2 (#23) Wall (Typical) (#26) Sediment/Debris at Cleaning (#24) Wall Condition Section 4 (#27) Sediment & Debris 8-24 at Cleaning 7

8 Section A-3: Detailed Report of Inspection A-3.1 INSPECTION AND RESERVOIR DATA Customer Name: City of Glenwood Springs, CO Reservoir Name: Canyon South (Raw Water) Contact Person: Jerry Wade Location: Glenwood Springs, CO Contact Phone: Type: On-Grade Job Number: A Material: Welded Steel Inspection Date: 10/23/2012 Capacity: 250,000 gallons Dive Supervisor: Jim Nilsson Diameter: 36' Diver: Byron Adams Height: 38' Tender: Dana Gaboury Floor S.F.: 1,017 Last Inspection: n/a Built By: D & R Tank Co., NM Last Service By: n/a Built Date: 2001 Liquid Level 37' Courses 5 A-3.2 TANK ETERIOR Tank Quadrants: Access Hatch O = Origin Q1 12:00-3:00 Q2 3:00-6:00 Q3 6:0009:00 Q4 9:00-12:00 Key: N/A- Not Applicable, Excellent (E)- like new condition, no repairs needed. Good- Cosmetic problems only, repair if wanted. Fair- Minor problems, repairs needed, not immediate. Poor- major problems, structural or like, immediate repairs needed. Reservoir Exterior Condition Pictures Comments Component NA Ex Good Fair Poor #'s Site Security Protective Fence (0) No protective fence Lock on Gate/Ladder No Lock Out Building(s) 1 Exterior Ladder Cage Foundation Concrete Anchor Bolts Column Shoes Tower Posts Cotter Pins Riser Pipe Vertical Condition Stay Rods Frost Casing Continued 8

9 TANK ETERIOR (Continued) Key: N/A- Not Applicable, Excellent (E)- like new condition, no repairs needed. Good- Cosmetic problems only, repair if wanted. Fair- Minor problems, repairs needed, not immediate. Poor- major problems, structural or like, immediate repairs needed. Reservoir Exterior Condition Pictures Comments Component NA Ex Good Fair Poor #'s Indications of Leakage None observed Riser Pipe Expansion joints Balcony Balcony Floor Reservoir Exterior Course 1 Course 2 Course 3 Course 4-5 Exterior Roof Thin top coat, primer shows Quadrant 1 Quadrant 2 Quadrant 3 Quadrant 4 Vents (1) Roof Vents Pan Vent Side Vents Thin and peeling top coat Vent Screen(s) (paint) Telemetry Liquid Level Indicator Manway Access (2) Quadrant 2 & 4 Antenna (0) Access Hatch Plumbing Overflow Other Exterior Paint Condition Tank Sides Tank Roof Overall Ext. Condition 9

10 INSPECTION REPORT Tank Quadrants: October 23, 2012 Access Hatch O = Origin Q1 12:00-3: Q2 3:00-6:00 Q3 6:0009: Q4 9:00-12:00 A-3.3 TANK INTERIOR Key: N/A- Not Applicable, Excellent (E)- like new condition, no repairs needed. Good- Cosmetic problems only, repair if wanted. Fair- Minor problems, repairs needed, not immediate. Poor- major problems, structural or like, immediate repairs needed. Reservoir Interior Condition Pictures Comments Component NA Ex Good Fair Poor #'s Access Ladder Access Hatch (1) Plumbing Inlet (1) quadrant 4 Overflow (1) Outlet 18 Columns Center Support Column Satellite Columns (0) Manway Access (2) Water Float Cathodic Protection No protection present Assembly Float Anodes Telemetry (0) Ceiling Quadrant 1 Quadrant 2 Quadrant 3 Quadrant 4 Floor Quadrant 1 Rust nodules less than 2% Quadrant 2 Rust nodules less than 2% Quadrant 3 Rust nodules less than 2% Quadrant 4 Rust nodules less than 2% (Continued) 10

11 Tank Quadrants: Access Hatch O = Origin Q1 12:00-3: TANK INTERIOR (continued) Q2 3:00-6:00 Q3 6:0009:00 Q4 9:00-12: Key: N/A- Not Applicable, Excellent (E)- like new condition, no repairs needed. Good- Cosmetic problems only, repair if wanted. Fair- Minor problems, repairs needed, not immediate. Poor- major problems, stuctural or like,immediate repairs needed. Reservoir Interior Condition Pictures Comments Componet NA Ex Good Fair Poor #'s Wall Quadrant 1 Course 1 (Lowest) Course 2 Course 3 Course 4-5 rust nodules > 2% Quadrant 2 Course 1 (Lowest) Course 2 Course 3 Course 4-5 rust nodules > 2% Quadrant 3 Course 1 (Lowest) Course 2 Course 3 Course 4-5 rust nodules > 2% Quadrant 4 Course 1 (Lowest) Course 2 Course 3 Course 4-5 rust nodules > 2% Sediment Quadrant 1 Quadrant " sand, leaves, Quadrant 3 branches, rocks, trash, Quadrant 4 compost and even live fish Water Condition No oil onsurface Particulates Heavy Visability Fair Temperature Cold Overall Interior Condition 11

12 A-3.4 Tank Technical Testing Dry-Film Thickness Dry-film thickness (DFT) is the thickness of a coating after it has cured. DFT measurements on the tank were taken on 10/18/2012. DFT measurements were recorded using a PosiTest Model FM Coating Thickness Gage developed for the non-destructive measurement of non-magnetic coatings on ferrous surfaces. The PosiTest FM Coating Thickness Gage is a magnetic pull-off thickness gage. Testing with magnetic gages is sensitive to surface roughness, curvature, substrate thickness, and the make-up of the metal alloy. Typical tolerance is ± 5%. Cross-Cut Tape Test ADS conducted an ASTM D-3359 coating adhesion and flexibility test on the exterior of the Canyon South water tank. The test site was on the exterior surface of section 1 (steel section closest to the ground). The cross cut tape test resulted in no pull-away. Cross-cut tape test result: 5B Advanced Diving Services employs this test method to allow us to test both interior and exterior tank surfaces. Only exterior surfaces were tested on the Canyon South tank. The readings were taken from various spots of the tank exterior. Six to eight readings were taken from each quadrant. DFT readings were as follows: ETERIOR DRY FILM THICKNESS IN MILS DFT Quadrant Quadrant Quadrant Quadrant Reading #1 #2 #3 # Minimum Maximum Average Average of 32 readings = 6.5 mils 12

13 Paint Samples Collection of internal and external paint samples for metal analysis was not conducted by ADS at the request of Glenwood Springs during on-site inspection and cleaning. Corrosion Evaluation The tank interior showed minimal corrosion. Corrosion density was between 0 and 1 on the ASTM standard rating chart. Ultrasonic Testing Advanced Diving Services Incorporated employs a Cygnus Instruments Dive, digital ultrasonic multiple-echo thickness gauge to provide accurate measurement(s) of metal thickness. The gauge was last calibrated by Cygnus on 09/25/2012. Cygnus Instruments declares accuracy of 0.1 mm when calibrated in accordance with Cygnus Instruments calibration procedures. The Canyon South tank floor thickness was tested in each quadrant. Results are as follows: Measurements: Redwood Tank Name Thickness Units Probe Type Quadrant mm 2.25 MHz 13 mm Quadrant mm 2.25 MHz 13 mm Quadrant mm 2.25 MHz 13 mm Quadrant mm 2.25 MHz 13 mm 13

14 Conclusion and Recommendations Tank Condition ETERIOR: GOOD INTERIOR: GOOD Recommendations Immediate Add 2 additional roof vents Add 7 protective fence to tank perimeter Check intake screen(s) from spring(s), excess debris entering tank (rocks, branches, leaves, and fish). Secure manhole cover(s). Water bottles were also found in tank. Epoxy repairs to tank interior coating failures (less than 2% of surfaces) Not Immediate Paint exterior roof. Ongoing Maintenance Inspection and cleaning every 1 year (until debris intake resolved). ESTIMATED COST OF REPAIRS # RECOMMENDATION(S) Time Estimate Count Unit Cost Total IMMEDIATE REPAIR 1 Install 2 additional roof vents (Done while tank is full and in service) 1 DAY 2 $ $1, Install 7' perimeter fence OBTAIN BID 1 BID BID 3 Inspect intake screen(s) (currently excess bebri entering tank) 4 Interior Epoxy Repairs (Done while tank is full and in service) 14 Internal, Glenwood Water 1 1/2 DAY (schedule with Canyon South tank 1 $1, $1, NOT-IMMEDIATE 5 Power wash and re-paint exterior roof* 2 DAYS 1 $5, $5, ONGOING MAINTENANCE 6 Clean & Inspect every year (until sediment/debris resolved) 1 DAY 1 $3, $3, * Painting bid does not include possible lead base paint containment and/or removal

15 All surface and underwater repairs and recommendations, except sandblasting, can be performed by Advanced Diving Services, Inc. with the reservoir remaining in service. ADVANCED DIVING SERVICES, INC. James M. Nilsson Director I have reviewed the Diver Inspection Report of the Glenwood Springs, Canyon South Water Tank. Based on the information available in the report I agree with the inspection method, coating analysis and recommendations stated by Advanced Diving Services Inc. Dahl J. Dalton NACE Coating Inspector CIP Certification Number