NASSCO s Pipeline Assessment and Certification Program (PACP) Overview Rod Thornhill, PE White Rock Consultants Dallas, Texas

Transcription

1 MWEA Collections Seminar October 1, 2009 NASSCO s Pipeline Assessment and Certification Program (PACP) Overview Rod Thornhill, PE White Rock Consultants Dallas, Texas

2 Introduction to NASSCO Founded in 1976, NASSCO is the National Association of Sewer Service Companies. Our mission is to set industry standards for the rehabilitation of underground pipelines and to assure the continued acceptance and growth of trenchless technologies. NASSCO is an impartial organization serving all facets of the sewer service industry.

3 NASSCO s 4-Step Industry Education Approach

4 Step 1: Understanding Deterioration Mechanisms Educate the Industry on how to identify problems in their sewer infrastructure system with a common defect identification program PACP, MACP, LACP. Define sewer pipeline deterioration modes that are common to systems containing similar materials but in different locations and climate conditions. Assist Engineers and Municipalties on setting renewal priorites based on the documented condition of the sewer system.

5 Step 2: Understanding Available Technologies Continually educating the industry on the existing and developing technolgies that can be used to renew the sewer infrastructure Provide the tools for selecting the correct renewal technology for the sewer pipeline documented conditions Working with the Trenchless Technology Center (TTC) of Louisiana Tech University to develop a computerized Trenchless Assessment Guide for Rehabilitation (TAG-R). This guide will give the industry the tool to quickly and effectively determine correct technology applications based on the existing condition of the pipeline

6 Step 3: Understanding Specifications Write standard performance-based specifications that are made available to the Industry Include quality assurance and quality control standards that promote quality product installation/application/construction Provide standards for testing of the installed products to verify that the customer receives the product purchased

7 Step 4: Inspector Training Certify and train project engineers and field inspectors to better understand each technology and how the technology is constructed in the field Understanding key elements of the contract specifications to ensure successful installations Define quality assurance requirements Provide standard checklists and forms for accurate field documentation

8 We Need to Avoid Sewer Problems Finding Us!

9 Miles of Pipe History of Sewer Pipe Installation EPA Gap Analysis

10 Age in Years Average Age of Sewer Pipes EPA Gap Analysis

11 Estimated Condition of Sewer Pipes In 1980 Failure Poor/Very Poor Fair Good Excellent EPA Gap Analysis

12 Estimated Condition of Sewer Pipes In 2020 Failure Poor/Very Poor Fair Good Excellent EPA Gap Analysis

13 Percent Estimated Change in Pipe Condition Failed Poor/Very Poor Fair Good Excellent EPA Gap Analysis

14 Summary Of TV Inspection History Only been around about 45 years Made possible the creation of the trenchless technology industry Most sewers today were only televised years after construction Large amount of existing TV data Need effective way to manage volume of data

15 Industry Parallels Standard Methods for the Examination of Water and Wastewater (Standard Methods) standardmethods.org Joint Publication of APHA, AWWA, WEF Began in 1905, now in 20 th, Edition, 350 separate measurements

16 Proactive Renovation and Replacement using APWA Paver program The pavement Management industry has used condition assessment to justify costeffective proactive renovation

17 Origin of Water Research Centre (WRc) Condition Codes UK codes initially developed late 70s, early 80s. Adaptations for use in Australia, Canada, and elsewhere. Prior to NASSCO codes US industry had no single standard coding system. WRc codes were modified and widely used in North America, however no standard version was ever established

18 Origin of WRc Condition Codes (Cont d) Applied to help correlate sewer condition and sewer rate charges after privatization of industry in the UK. NASSCO obtained assistance from WRc in 2001 and first PACP class held in Jan 2002 Standardization concept more important than the benefits of one code system compared to another.

19 Reasons for CCTV Survey Routine Operational Requirements Proactive inspection to identify potential failures and for planning routine O&M and renovation programs. Troubleshooting Investigation of problem incidents to select remedial action Compliance with Mandated Programs Inspection and data collection to support programs such as C-MOM and GASB-34.

20 Reasons for CCTV Survey (Cont d) Acceptance Testing Inspection of new or renewed sewers to insure that construction met specifications and to document as-built conditions. I/I or CIP Projects Examples of the type projects normally conducted by specialty firms or engineering consultants. The PACP emphasized that all TV Inspections should be conducted thoroughly and consistently regardless of the reason for TV

21 Desired Results of a CCTV Survey Record and Archive All Descriptive Data Develop a Condition Rating for Each Line Provide Follow-up Recommendations Display Results on a Map Establish Benchmarks To Compare With Future Inspections Of Same Line Estimate Probability of Failure and Life Expectancy

22 Why Standardization of Codes is Important Allows for more effort to be placed on consistency of data and utilization of data rather than development of utility-specific or projectspecific standards Provides the capability of benchmarking sewers within a single utility as well as from one geographical area of the US to another Provides the ability to detect change due to deterioration over time

23 Why Standardization of Codes Important (Cont d) Provides better opportunities for integrating data from different software programs Improves confidence in the description of pipe conditions that will provide cost savings during renewal Creates many opportunities for continual improvement by consistently describing conditions in a standard way over time Advances the professionalism of TV Inspection industry

24 Summary of NASSCO Pipeline Assessment and Certification Program (PACP) Modification/Adoption of standard codes and ratings Training and certification of operators Standard NASSCO data format Certification of software vendors Defect Grading and Severity Ratings for pipelines Protocol for Quality Control of PACP data Now includes manhole assessments (MACP) and soon lateral assessments (LACP)

25 Modification/Adoption of standard codes and ratings Adapt UK codes to the United States market Re-enforce maintenance related defect codes Add codes for corrosion evaluation/assessment Develop codes specific to rehabilitated sewers

26 Training and Certification of Users Understanding of codes and interpretation of defects Use of codes in forms and software Two day course with certification exam Includes review of pipeline deterioration mechanisms. Approximately 9,000 Users trained and adopted by several hundred utilities

27 PACP Training Explains use of Pipe has a combination of longitudinal and circumferential cracks Coding Distance (feet) Code Value Circumferential Continuous Video Joint location defect Ref Group / Modifier / S/M/ Inches % At / To Descrip severity L 1st 2nd from 80.3 FM J 08 05

28 Hydrogen Sulfide Attack STAGE 1 Inverted Syphon / Force Main Under anaerobic (septic) conditions, sulfate present in the wastewater is converted to sulfides within the slime layer inside the pipe. Force mains generally flow full with little aeration therefore likely points for sulfide production. Dissolved oxygen levels must be near zero in order for sulfide production to occur. STAGE 2 Discharge manhole/gravity sewer Sulfides in the wastewater are released by turbulent conditions at discharge point into the sewer atmosphere and form hydrogen sulfide gas (H2S).The H2S condenses on the pipe surfaces and is converted by bacteria into a weak sulfuric acid. The sulfuric acid attacks concrete and metal surfaces. STAGE 1 Gravity sewer Under anaerobic (septic) conditions sulfate present in the wastewater is converted into sulfides within the slime layer. Sewers with laminar flow therefore little aeration are most susceptible to low dissolved oxygen levels STAGE 2 Turbulence releases dissolved sulfides into the sewer atmosphere in the form of hydrogen sulfide (H2S). The H2S then condenses on sewer surfaces in the form of sulfuric acid. The sulfuric acid attacks cement based materials and metals.

29 PACP Concrete Pipe/H2S Damage Descriptors Roughness increased (SRI) Aggregate visible (SAV) Aggregate projecting (SAP) Aggregate missing (SAM) Reinforcement Visible (SRV) Reinforcement Projecting (SRP) Reinforcement Corroded (SRC) Missing Wall (SMW)

30 Roots - Medium (RM) Used when the roots are 50% or less of the cross-sectional area Distance (feet) Code Value Circumferential Continuous Video Joint location defect Ref Group / Modifier / S/M/ Inches % At / To Descrip severity L 1st 2nd from RM S J 07 05

31 Certification of Software Vendors All data fields conform to NASSCO standards Software has the ability to export and import seamlessly to NASSCO standard data format Data exported from one certified software is identical to software from another PACP Standard database template freely available to anyone

32 PACP Data Standards Data dictionary defines: Field names Field character number and format Valid field data entries Standard Database Format (ACCESS) Provide the ability to seamlessly combine data from various projects

33 PACP QA/QC Protocol Implementation Important Process for confirming the accuracy of PACP coding Efficient collection of PACP data requires accurate coding (only code once) PACP inspections are selected randomly for checking by Expert Score is based on percentage of correct entries divided by total possible entries

34 PACP QA/QC Protocol (Cont d) Protocol will find gross errors or misinterpretations by technicians very early in the PACP coding process Can be used by utilities, contractors, or engineers Relatively small sample set can control a large number of inspections by using random selection of inspections once

35 Examples of common errors can be used to improve coding quality VC pipe material Although the Missing Wall code (SMW) and the Hole code (H) describe similar defects, missing wall is used where the concrete is completely deteriorated, with no pipe material left.

36 Keys to Re-Engineering TV Data Management Pick a standard, preferably a nationally accepted standard Understand TV Data Management is a program, and commit to it Process all data from all sources consistently Think long term, big picture

37 PACP Essential Tool for Estimating Remaining Life Records in detail the current condition of pipe Identifies deterioration factors inside the pipe that affect rate of deterioration Benchmarking of old and new inspections is used to ground truth rates of deterioration Long term use of standard codes provides continual improvement PACP-based Life Expectancy estimates will constantly be corrected using updated TV inspection condition data.

38 Utilities need to Establish Level of Service Objectives Traditional Levels of Service are Occurrence of overflows Frequency of maintenance calls Emerging Levels of Service are; Current condition of pipeline Life expectancy of pipe Probability of Failure

39 Don t Ignore Retrofitting Existing Data Very inexpensive compared to obtaining new data Audio and Video often of excellent quality Can add up quickly to a considerable portion of the system Provides immediate ability to assess rate of deterioration by comparing old data to new

40 Summary Standardization will increase confidence in data and the use of the data Develop condition ratings and recommended followup for every line televised Make mapping of results an integral part of the process Don t ignore value of the existing TV data Standardized pipe condition data will be an essential tool for short term and longer sewer collection system management