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How might we better assess the condition of our aged Pumping Mains, particularly for pipes with sharp bends and sections filled with water?
Challenge Owner
Background
70 km of Pumping Mains (PMs) is part of Singapore's used water network conveying used water from the pumping stations to the downstream gravity sewers, towards the Water Reclamation Plants (WRP) for treatment. These PMs are buried underground at depths ranging from 3m to 10m and are made of various materials such as Ductile Iron Pipe (DIP), Cast Iron Pipe, Asbestos Cement Pipe, and Steel.
Leaks from PMs can result in disruption to used water conveyance and can have impact to public health and water resources. Internal structural conditions of the PMs are therefore inspected periodically to detect for potential failure points and for rectification to be carried out accordingly. Aged PMs are also identified and renewed through pipe rehabilitation to restore the pipe’s structural condition.
Current Practice
The current methodology to assess the condition of PMs involves visual inspection using conventional video surveillance devices, e.g. CCTV. These devices enable the recording of imagery of the internal condition of the PMs, which helps to identify locations with leaks, damages or abnormalities. This information is then used to determine the appropriate follow-up actions or prioritising the PMs for rehabilitation.
CCTV devices are inserted into the PMs via man-entry into the chamber. Pumping mains needs isolated and drained in preparation of the condition assessment/inspection by the CCTV devices. This means that the pumping station will have to operate with a reduced pipe capacity during a planned inspection. In some cases, inspection needs to be done at off peak hours to ensure undisrupted used water conveyance.
Before the insertion of CCTV devices, water within the chamber and remnant water within the pumping main are first removed via the insertion of a small submersible pump or by a vacuum tanker. The amount of water that can be removed via the pumps to maintain a relatively low water level/dry condition for CCTV visual inspection can be a challenge as the depth of the pumping main increases.
The existing video surveillance devices (e.g. CCTV) also come with some common limitations such as:
We are seeking for solutions such as robotics systems or inspection tools that can perform condition assessments of PMs. We are open to both visual and non-visual inspection methods, as long as the data collected can be used to accurately identify or derive potential leak spots or failure areas.
Visual inspection methods should overcome as much of the limitations highlighted above and provide clear video footage of the PMs, regardless of the conditions within the PMs. Non-visual inspection methods could offer additional data and insights regarding the PMs, such as pipeline alignments, thickness of the pipeline and corrosion rate, which could be considered to determine the priority for rehabilitation.
The solutions we are seeking are summarised to the following:
A. Performing condition assessments with the ability to traverse the entire length of a PM, including sharp bends and/or multiple bends
Solutions that can traverse the entire length (approx. 1km) of a PM from one end to the other are desirable to simplify the inspection operations and minimise the need to insert video surveillance device through the Access Chambers. The solution can be deployed from within a Pumping Station and retrieved at the Discharge Chamber found at the end of the PM. If this is not possible, the solution should at least be able to travel 200m or more from Access Chambers located along the PMs to ensure that the inspection can covers the entire stretch of a PM.
B. Performing condition assessments without requiring isolation and draining operation of the PMs
Conducting condition assessments of PMs without the need to isolate and drain them can result in significant savings in terms of manpower and time. Therefore, we are keen to explore solutions that can perform condition assessments without requiring isolation and draining operations. However, we are also open to methods that involve draining the PMs if the methods provide more accurate, detailed, and precise data that can support the planning of rehabilitation works and help project the lifespan of the PMs.
C. Performing condition assessments via exterior of the PMs
We are also willing to consider solutions that require installation on the exterior of the pumping main or pipe fittings if the installation does not require trenching or extensive construction works.
A. Operational Requirements
1. The solution shall be able to navigate through sharp bends and/or multiple bends whilst avoiding potential entanglements.
2. The solution shall include a method to assess the condition for the section of PMs that is filled with water and be sufficiently waterproof if required to be submerged in water.
3. The solution should be able to travel and assess the conditions within pumping mains with diameters ranging from 100mm to 1100mm.
4. The deployment of the solution into the PMs would differ depending on the piping diameter.
a. For PMs that have larger diameters (300mm and above), the solution can be deployed through the Access Chamber located along the PM. The Access Chamber is commonly a T-pipe with a top opening of diameter ranging from 300 to 500mm.
b. For PMs that have smaller diameters, the solution will need to be deployed through openings created from dismantling the pipe fittings.
5. If the solution needs to be tethered, the cable shall be interchangeable and allow a travelling distance of 200m and above.
6. Please provide the method statement of how the solution would be deployed and retrieved from the Pumping Main in your proposal.
B. System Requirement
1. Visual inspection methods
a. The video cameras provided shall have a resolution of 1080p or higher and be capable of capturing video footage underwater.
b. The solution shall be fitted with suitable illumination devices to ensure clear video footage is recorded during the deployment.
c. The solution shall be explosion-proof.
2. Non-visual inspection methods
a. The data shall be analysed and interpreted to provide easy to understand information regarding the condition of the PMs, e.g. alignment, thickness and corrosion rate.
b. Please indicate in your proposal, the type and diameter range of piping that the proposed method can effectively assess the condition.
C. Conditions within the PM
1. Pumping Mains are in operation.
a. Pressure range: 1 – 2 bar
b. Flow velocity range: 1 – 2 m/s
2. Pumping Mains are drained.
a. Sections of up to 150m can remain filled with water, despite the effort to drain off the section filled with water using a vacuum tanker. This is due to the significant head loss caused by the depth of the pumping main and the distance of the water-filled section from the deployment location of the vacuum tanker.
b. Low or no lighting.
c. The presence of water vapour that can cause cameras to produce foggy visuals.
D. ‘Good-to-have’ Features
The following ‘good-to-have’ features which are not mandatory but can be useful for our operations:
1. Automatic assessment and classification of the pipeline conditions using WRc or equivalent grading.
2. Recommendation system that can determine the best course of action to extend the lifespan of the pipeline.
Limitations of trialled technologies
1. Push Rod CCTV
a. Typically deployed in smaller PMs with diameters of 100–150mm.
b. Maximum deployment range of 100m.
c. Unable to transverse through sharp bend and/or multiple bends.
d. Poor visuals when submerged in water.
2. CCTV Robotics Crawler
a. Typically deployed in PMs with diameters of 150mm and above.
b. Maximum deployment range of 150m.
c. Unable to transverse through sharp bend and/or multiple bends.
d. Poor visuals when submerged in water.
3. Acoustic based Free-swimming Inspection Tool
a. Unable to meet the operation conditions required, i.e. pressure and flow velocity, to produce meaningful inspection results.
b. The presence of debris within the pumping mains generates noise as a result.
Condition Assessment of User Water Pumping Mains
Zac and his team have been assigned the task of ensuring that the used water pumping main island wide are well-maintained and mitigation plans are developed to prevent pipe leakage incidents that could disrupt surface activities. The team is particularly interested in understanding the condition of the pumping main that is buried deep underground and was installed over several years ago, so that the prioritization of pipe which may require rehabilitation or replacement can be better decided and planned out. To achieve this outcome, the team is looking for a solution that provide assessment of the structural integrity of the pipe. Such solution could comprise inspection tool and analytics system, where the inspection tool that could be deployed into the pipe at the pumping station or access chambers along the pipe alignment, while the system analyses the pipe’s condition. The solution must be able to collect the necessary information within the operating range of the pumping installation (i.e. pressure, velocity, flow rate), and inspection must be able to navigate through the entire stretch of the pumping main, whether it is dry or submerged conditions, and provides clear and meaningful dataset. Examples of meaningful and useful information can include but not limited to the pipe’s structural integrity of the pumping main, material loss of host pipe (e.g. steel, ductile iron, HDPE), material loss of liner (e.g. cement, HDPE, CIPP lining), which could be used to determine how maintenance and replacement for the pumping main should be prioritized to prevent leak from occurring.
By the end of the pilot, the project should aim to develop a site-tested prototype that can effectively perform condition assessment of the entire stretch (approx. 1km) of a PM. A method statement has to be established which details the procedures to carry out the deployment. After each deployment, a report has to be provided which documents the detailed description of the condition of pipeline.
The pilot project is to be completed within a period of 18 months. Below are the suggested project scope and timeline:
1. Identify and validate user and site requirements – 1 month
2. Build and customise prototype – 1-4 months
3. Solution deployments and iterations to complete the inspection for the entire stretch of Ayer Rajah Pumping Mains – 6-12 months
4. Complete techno-economic analysis and finalise reports – 1 month
If the pilot is successful, PUB would be interested to deploy the solution through a service model where the equipment is owned, operated, and maintained by the company.
Challenge Owner
Background
70 km of Pumping Mains (PMs) is part of Singapore's used water network conveying used water from the pumping stations to the downstream gravity sewers, towards the Water Reclamation Plants (WRP) for treatment. These PMs are buried underground at depths ranging from 3m to 10m and are made of various materials such as Ductile Iron Pipe (DIP), Cast Iron Pipe, Asbestos Cement Pipe, and Steel.
Leaks from PMs can result in disruption to used water conveyance and can have impact to public health and water resources. Internal structural conditions of the PMs are therefore inspected periodically to detect for potential failure points and for rectification to be carried out accordingly. Aged PMs are also identified and renewed through pipe rehabilitation to restore the pipe’s structural condition.
Current Practice
The current methodology to assess the condition of PMs involves visual inspection using conventional video surveillance devices, e.g. CCTV. These devices enable the recording of imagery of the internal condition of the PMs, which helps to identify locations with leaks, damages or abnormalities. This information is then used to determine the appropriate follow-up actions or prioritising the PMs for rehabilitation.
CCTV devices are inserted into the PMs via man-entry into the chamber. Pumping mains needs isolated and drained in preparation of the condition assessment/inspection by the CCTV devices. This means that the pumping station will have to operate with a reduced pipe capacity during a planned inspection. In some cases, inspection needs to be done at off peak hours to ensure undisrupted used water conveyance.
Before the insertion of CCTV devices, water within the chamber and remnant water within the pumping main are first removed via the insertion of a small submersible pump or by a vacuum tanker. The amount of water that can be removed via the pumps to maintain a relatively low water level/dry condition for CCTV visual inspection can be a challenge as the depth of the pumping main increases.
The existing video surveillance devices (e.g. CCTV) also come with some common limitations such as:
We are seeking for solutions such as robotics systems or inspection tools that can perform condition assessments of PMs. We are open to both visual and non-visual inspection methods, as long as the data collected can be used to accurately identify or derive potential leak spots or failure areas.
Visual inspection methods should overcome as much of the limitations highlighted above and provide clear video footage of the PMs, regardless of the conditions within the PMs. Non-visual inspection methods could offer additional data and insights regarding the PMs, such as pipeline alignments, thickness of the pipeline and corrosion rate, which could be considered to determine the priority for rehabilitation.
The solutions we are seeking are summarised to the following:
A. Performing condition assessments with the ability to traverse the entire length of a PM, including sharp bends and/or multiple bends
Solutions that can traverse the entire length (approx. 1km) of a PM from one end to the other are desirable to simplify the inspection operations and minimise the need to insert video surveillance device through the Access Chambers. The solution can be deployed from within a Pumping Station and retrieved at the Discharge Chamber found at the end of the PM. If this is not possible, the solution should at least be able to travel 200m or more from Access Chambers located along the PMs to ensure that the inspection can covers the entire stretch of a PM.
B. Performing condition assessments without requiring isolation and draining operation of the PMs
Conducting condition assessments of PMs without the need to isolate and drain them can result in significant savings in terms of manpower and time. Therefore, we are keen to explore solutions that can perform condition assessments without requiring isolation and draining operations. However, we are also open to methods that involve draining the PMs if the methods provide more accurate, detailed, and precise data that can support the planning of rehabilitation works and help project the lifespan of the PMs.
C. Performing condition assessments via exterior of the PMs
We are also willing to consider solutions that require installation on the exterior of the pumping main or pipe fittings if the installation does not require trenching or extensive construction works.
A. Operational Requirements
1. The solution shall be able to navigate through sharp bends and/or multiple bends whilst avoiding potential entanglements.
2. The solution shall include a method to assess the condition for the section of PMs that is filled with water and be sufficiently waterproof if required to be submerged in water.
3. The solution should be able to travel and assess the conditions within pumping mains with diameters ranging from 100mm to 1100mm.
4. The deployment of the solution into the PMs would differ depending on the piping diameter.
a. For PMs that have larger diameters (300mm and above), the solution can be deployed through the Access Chamber located along the PM. The Access Chamber is commonly a T-pipe with a top opening of diameter ranging from 300 to 500mm.
b. For PMs that have smaller diameters, the solution will need to be deployed through openings created from dismantling the pipe fittings.
5. If the solution needs to be tethered, the cable shall be interchangeable and allow a travelling distance of 200m and above.
6. Please provide the method statement of how the solution would be deployed and retrieved from the Pumping Main in your proposal.
B. System Requirement
1. Visual inspection methods
a. The video cameras provided shall have a resolution of 1080p or higher and be capable of capturing video footage underwater.
b. The solution shall be fitted with suitable illumination devices to ensure clear video footage is recorded during the deployment.
c. The solution shall be explosion-proof.
2. Non-visual inspection methods
a. The data shall be analysed and interpreted to provide easy to understand information regarding the condition of the PMs, e.g. alignment, thickness and corrosion rate.
b. Please indicate in your proposal, the type and diameter range of piping that the proposed method can effectively assess the condition.
C. Conditions within the PM
1. Pumping Mains are in operation.
a. Pressure range: 1 – 2 bar
b. Flow velocity range: 1 – 2 m/s
2. Pumping Mains are drained.
a. Sections of up to 150m can remain filled with water, despite the effort to drain off the section filled with water using a vacuum tanker. This is due to the significant head loss caused by the depth of the pumping main and the distance of the water-filled section from the deployment location of the vacuum tanker.
b. Low or no lighting.
c. The presence of water vapour that can cause cameras to produce foggy visuals.
D. ‘Good-to-have’ Features
The following ‘good-to-have’ features which are not mandatory but can be useful for our operations:
1. Automatic assessment and classification of the pipeline conditions using WRc or equivalent grading.
2. Recommendation system that can determine the best course of action to extend the lifespan of the pipeline.
Limitations of trialled technologies
1. Push Rod CCTV
a. Typically deployed in smaller PMs with diameters of 100–150mm.
b. Maximum deployment range of 100m.
c. Unable to transverse through sharp bend and/or multiple bends.
d. Poor visuals when submerged in water.
2. CCTV Robotics Crawler
a. Typically deployed in PMs with diameters of 150mm and above.
b. Maximum deployment range of 150m.
c. Unable to transverse through sharp bend and/or multiple bends.
d. Poor visuals when submerged in water.
3. Acoustic based Free-swimming Inspection Tool
a. Unable to meet the operation conditions required, i.e. pressure and flow velocity, to produce meaningful inspection results.
b. The presence of debris within the pumping mains generates noise as a result.
Condition Assessment of User Water Pumping Mains
Zac and his team have been assigned the task of ensuring that the used water pumping main island wide are well-maintained and mitigation plans are developed to prevent pipe leakage incidents that could disrupt surface activities. The team is particularly interested in understanding the condition of the pumping main that is buried deep underground and was installed over several years ago, so that the prioritization of pipe which may require rehabilitation or replacement can be better decided and planned out. To achieve this outcome, the team is looking for a solution that provide assessment of the structural integrity of the pipe. Such solution could comprise inspection tool and analytics system, where the inspection tool that could be deployed into the pipe at the pumping station or access chambers along the pipe alignment, while the system analyses the pipe’s condition. The solution must be able to collect the necessary information within the operating range of the pumping installation (i.e. pressure, velocity, flow rate), and inspection must be able to navigate through the entire stretch of the pumping main, whether it is dry or submerged conditions, and provides clear and meaningful dataset. Examples of meaningful and useful information can include but not limited to the pipe’s structural integrity of the pumping main, material loss of host pipe (e.g. steel, ductile iron, HDPE), material loss of liner (e.g. cement, HDPE, CIPP lining), which could be used to determine how maintenance and replacement for the pumping main should be prioritized to prevent leak from occurring.
By the end of the pilot, the project should aim to develop a site-tested prototype that can effectively perform condition assessment of the entire stretch (approx. 1km) of a PM. A method statement has to be established which details the procedures to carry out the deployment. After each deployment, a report has to be provided which documents the detailed description of the condition of pipeline.
The pilot project is to be completed within a period of 18 months. Below are the suggested project scope and timeline:
1. Identify and validate user and site requirements – 1 month
2. Build and customise prototype – 1-4 months
3. Solution deployments and iterations to complete the inspection for the entire stretch of Ayer Rajah Pumping Mains – 6-12 months
4. Complete techno-economic analysis and finalise reports – 1 month
If the pilot is successful, PUB would be interested to deploy the solution through a service model where the equipment is owned, operated, and maintained by the company.
