Size of sewer ball

Lessons from Parisian Sewers – Sewer Balls

Lessons from Parisian Sewers – Sewer balls

Author : Amanda Siqueria

On a recent trip to Paris, I convinced my husband and in-laws to come with me on an adventure into the underworld. Enter the sights and sounds of the Paris Sewer Museum (Musée des Égouts de Paris). Ever since I had read about the museum in a book (‘An Underground Guide to Sewers’, but Stephen Halliday) I had wanted to go.  

Tunnel cross sections in Parisian Sewers

Learning about the different tunnel cross sections used in Parisian sewers, Source: Author

Paris Sewer Museum (Musée des Égouts de Paris)

The museum is attached to a working sewer station that lets visitors explore the evolution of this hidden French infrastructure. Let’s just say, it’s a 4D experience, the fourth dimension being ‘smell’. That said, there was so much to look at and learn that the initial ‘wall’ of the odour was soon forgotten.

Picture of a sewer ball

Our first encounter with the sewer ball, Source: Author

Sewer Balls

Out of all of the things that we saw, the artefact that stood out the most were the ‘sewer balls’. The giant balls made of iron or wood were used to clear debris from the large diameter sewer tunnels.

Size of sewer ball

Me and my best mate, Source: Author

Sewer ball design

A lot of the tunnels were designed to be ‘visitable’, I.e. to provide manual access to the structure for inspection and maintenance purposes. In tunnels where this access was not provided, these ‘sewer balls’ were used, most often in siphon and outfall parts of the network. The diameter of the balls was slightly smaller than the diameter of structure they were inserted into so that they would be able to pass through unobstructed.

Diagram of sewer ball

Diagram of sewer ball use in Parisian sewers, Source: Brochure from Musée des Égouts de Paris 

Their unique design allowed for a small gap between the ball and the base of the tunnel through which the backed-up wastewater passed at high pressure and flushed out the sediment in front like a jet of water. The ball was then removed from the end of the structure and cycled through the tunnel until the structure was cleared of debris.

Teams of sewermen in the 1920s using various apparatus for clearing the sewers. Note picture of the sewer ball being used. 

Source: Halliday, S 2019, An Underground Guide to Sewers, Thame & Hudson

Lessons from history

Visiting this sewer museum, we learned not only about the sewer balls, but also the many other feats of engineering that were applied to wastewater collection and treatment in Paris. Although the balls themselves are no longer in use, it was interesting to see many of the same challenges that modern wastewater networks have, also existed at the time the network was first constructed. In the case of silt and debris removal, manual and physical methods are still a big challenge in modern sewers. Hashtags like #binthewipe and #weirdthingsinpipes illuminate some stark examples of modern sewer misuse. The challenges continue to grow in number with the increasing number of wet wipes and other rag material entering the network.  Perhaps a sewer ball revival is on the horizon? Either way, it’s an interesting reminder of the ingenuity of engineers in solving problems, and the need for awareness raising when it comes to sewer misuse.

Learn more about Sewer Network

VAPAR automates sewer and stormwater pipe condition assessment for councils, utilities and CCTV contractors.  Learn how we help improve the monitoring and maintenance of the underground pipes using AI.

About the author
crack in sewer pipe

Common errors with manual pipe inspection coding, learn more

Common errors with manual pipe inspection coding

None of us is infallible. We all make mistakes. The fact that we are human means there is always a margin for error. In whatever we do.  

 If you are a commercial airline pilot, the room for error is just not there. Lives are at stake if you make a fundamental error. So, there are many aspects that come into play to ensure that risk is mitigated. 

Planes, of course, are highly automated these days; autopilot can navigate and land the plane and arguably is less likely to make an error than a human. But the human is essential. You cannot rely on computers to do everything, and the human must be there in case of an emergency. The recent history of Boeing’s 737 Max is an example of what happens when this does not happen. This is where the best training comes in. Not just one-off training, but regular training and review. Then, of course, are the checklists and manuals. Specific processes to go through in every event. 

Boeing 737 image

Although planes are now highly automated, human input is still an essential element. 

So how does this relate to the coding of pipes? Well, unlike planes, CCTV camera surveys are not yet fully automated. The reporting system still heavily relies on human input to generate a report. Of course, the information is only as good as what is put into the system by humans. 

With pipe coding systems (and there are several of them around the world, including MSCC5 and PACP), there are a set of rules to follow in each instance. Fairly straightforward, right? – Well, yes, if everyone is trained the same way and sees the same thing. But we are humans, and we not only make mistakes but also see things from different perspectives. 

What one might see may be different to another, and this becomes apparent when you look through vast amounts of reports and footage. 

So, what are some common misconceptions, errors, and mistakes humans make when interpreting CCTV recordings? 

Cracks vs Fractures

Without doubt the most common. What is the difference, and how can you tell? A crack is just a broken line visible on the pipe wall, be it circumferential or longitudinal. It will not be open or moved apart; the pipe is still in place. A fracture you can clearly see where the pipe is open on the pipe wall and shows a visible ‘black line’, pieces of the pipe are still in place. 

crack in sewer pipe

Can you tell the difference between a crack and a fracture or cracks <1mm or >1mm” in Australia? 

Pipe Material or Material Change

Many times, the pipe material is coded wrong or missed completely. Often where there is a material change midline it is missed, and many coders can’t tell the difference between certain materials. Common types that get mixed up are pitch fibre and cast iron as they are both dark and can be hard to see. The difference between Vitrified clay and PVC and concrete and asbestos cement. 

Getting the code wrong here could lead to the wrong repair specification or inappropriate recommendations. With pitch fibre, this could cause a longer-term issue if the presence of the material is not identified at an early stage in the survey process and will affect the choice of no dig repairs or excavations. 

Broken vs Hole

Another one we see a lot is the difference between a broken pipe and a hole in the pipe. People’s definitions are mixed up here and without the correct training and reference materials these are often miscoded. A broken pipe shows pieces of pipe that have moved from their original place but are still there, whereas a hole is a visible hole in the fabric of the pipe with the pieces missing. 

 The broken pipe may need to be removed, whereas a hole has already gone. It may be necessary to recover the evidence. If this is coded wrongly then further work required may not be correctly identified, leading to further blockages. 

Junction or Connection

Lots of coders will confuse junctions with connections. The definition of a junction is one that is performed or purpose-made and built into the sewer. A connection, however, has been added afterwards, usually with a boss or just smashed into the pipe, causing a defect. 

 Junctions are meant to be there. If they are wrongly coded as connections, a recommendation may be made to remove and replace them when it’s not needed. Leading to costly, unnecessary excavations. 


Attached or settled, fine or course, grease, or encrustation. All areas where easy mistakes can happen. Encrustation is often coded as grease and vice versa.

So, what is the difference between grease and encrustation? The easiest way to remember is that grease is essential ‘man-made’ whereas encrustation is usually mineral deposits caused by nature. These are usually attached to the pipe. 

 Deposits can cause flow issues, blockages and reduction in hydraulic capacity in the pipe and these foreign materials can stick to the inner pipe wall and become relatively permanent. 

 Settled deposits can be fine (DE S) like sand or silt or coarse (DE R) like gravel or rubble. There are plenty of descriptor codes in this category which often leads to confusion and if in doubt the code (DS Z) is a catch-all for all deposits that can’t be classified by the other codes. 

 Getting the type of deposit right is important because it will build a case as to what the issue with the pipe is. The evidence is important, especially if the pipe is being abused with grease and fat. If it is coded wrongly, the correct action may not be taken where needed. 

Clock references

There are often errors in clock references. Either when inputting a ‘to and from’ or a specific point (and determining when its required). Also, the actual clock reference itself. One person’s 7 o’clock is another’s 8. 

Getting the position wrong could affect where patches are installed or how it affects the serviceability of the pipe. A hole at 11 o’clock is not so damaging as a hole at 7 o’clock if the pipe is running at half bore. 

sewer pipe junction

A junction at 3 o’clock or is that 4 o’clock? 


Used for several codes, percentages, like clock references, are open to human interpretation. Used in deformation, cross-sectional loss, and water levels these are often under or overestimated and not accurate.  

The extent of the intrusion or root mass or the water level is important to determine remedial action and the timescale. If cross-section loss is estimated at 50% when it’s only 20% this could overplay the urgency. 


So, can AI and automation, like the functionality provided by VAPAR,  help with these errors?  

Of course, the answer is yes! Setting out and agreeing on the exact parameters which define a code can allow the software to take out the subjectivity. Although, like a human, an AI will not be 100% accurate, 100% of the time. This is where the provision of a targeted human check of the AI outputs allows the accuracy to exceed using just the AI or Human capability. This approach is no different to how an airline pilot would use manuals and checklists on a plane to ensure the automated systems are working as intended. 

Of course, we are not dealing with hundreds of lives on a plane here, and these types of errors will not necessarily cause a catastrophic consequence. However, the pipe inspection coding errors in extreme cases can lead to the internal flooding of someone’s property or the pollution of a nearby water course.  A Combined Intelligence model, like that used by VAPAR, effectively merges the AI and human inputs to minimise mistakes, improve both accuracy and consistency, and generate efficiencies by grading pipes appropriately to be used in the asset management of piped networks. 

This article is Co-Authored by Nathan & Anthony

Learn more about Sewer Network

VAPAR automates sewer and stormwater pipe condition assessment for councils, utilities and CCTV contractors.  Learn how we help improve the monitoring and maintenance of the underground pipes using AI.


What is a Manhole, and What are the Parts of a Manhole?

Access and Maintenance of Sewers: Manholes

What is a Manhole?

Manholes, maintenance holes, sewer access points, sewer access chambers……. the list to describe them can be endless.  Regardless of what they’re called, let’s take a look inside them and what their basic function is? 


These are the assets that provide a surface connection to the underground sewer network below. Manholes split gravity sewer mains at regular intervals, often at changes in direction.  Their primary function is to provide access to pipes for cleaning, removing blockages, and allow condition assessment inspections by maintenance crews. 

Within the manhole there are a range of sub-components; it’s much more than just a hole. So now we know the basics, let’s jump in (not literally). 

Parts of a Manhole

Parts of manhole

Manhole Cover and Ring 

Generally round and constructed from cast iron with a concrete inset, the cover sits tightly inside the ring with the intention of creating an airtight seal to stop odours escaping, and surface inflow entering. In most cases, the cover should be flush with the surrounding ground surface level. 

Ladder/Step Irons 

Typically made from steel, although more recently non-corrosive materials, step irons are installed to enable maintenance personnel to climb down. In some cases, these are being removed, or not installed in new builds due to safety implications with workers lowered in using dedicated confined space entry equipment. 

Cone/Straight Back Taper 

Located just under the cover there is a taper or cone increasing in diameter to transition the internal diameter to a larger size at the sub-surface level. 

Cross section of manhole


Below the taper, sits the shaft. This leads down to the base of the manhole. In significantly deeper manholes there will be a notable separation between the shaft and chamber. The diameter of the shaft varies between 1m to 1.8m.


This is a flatter concrete surface prepared with the intention of providing an area where maintenance crew can position themselves and stand within the manhole above the pipe to perform any tasks that are required .


The channel is located at the center of the benching and is where the sewage/wastewater flows through the manhole. 


The invert is located within the channel and is the lowest part of the manhole. It is a crucial level which is set with reference to a specific datum, specifically to allow the water to flow by gravity to its intended location. 


These are the flow entry and exit points of the manhole. There can be multiple inlets to the manhole but almost always only one outlet. In special instances a bifurcation manhole may be installed that splits the flow into separate downstream pipes. 

Location of Manholes 

Their locations can vary from in the roadway, within properties and almost anywhere that sewer pipes are located (which some of the time isn’t the most practical). With relation to the sewer network, they are generally located at changes in direction, grade/slope, invert level or intersection of another sewer branch. 

About the Author - Anthony Woodhouse

Learn more about Sewer Network

VAPAR automates sewer and stormwater pipe condition assessment for councils, utilities and CCTV contractors.  Learn how we help improve the monitoring and maintenance of the underground pipes using AI.

Patch repair needed in new pipe

Streamlining CCTV Pipe Acceptance Testing

Streamlining CCTV Pipe Acceptance Testing

What is a pipe acceptance test?

Utilities that manage sewer and stormwater networks increasingly have reticulation pipework extensions constructed by contractors as part of developer works. These pipes are commissioned and adopted by the utility. In many cases, the new pipes are built as part of a larger development that incorporates road, footpath, and lot divisions for sale. It is important for public utilities to have assurance that these new pipe assets have been constructed to their approved design and are defect free prior to them taking ownership.

This inspection, or CCTV acceptance test, is a critical part of the process that confirms the newly constructed pipe meets the requirements set out by the relevant authority. A CCTV inspection for acceptance is intended to focus on a range of areas, including:

  • Surface damage of internal surfaces
  • Cracking, breaking, or holes in the pipe wall
  • Obstructions or deposits within the pipe
  • Constructed grade (fall) of the pipe
  • Deformation
  • Joint defects
  • Ponding of water, or flat sections
  • Connection and junctions
  • Length of constructed pipe

Public utilities usually specify that these inspections be completed to the relevant inspection reporting code and must meet minimum standards to be approved for contributed asset handover.

Patch repair needed in new pipe

Figure 1- Cured-in-place patch to rectify a pipe defect in a new pipe

Who completes and approves an acceptance test?

Civil construction companies are usually required to engage an independent CCTV sub-contractor to complete an acceptance test, with a qualified engineer providing sign-off on the CCTV results and other accompanying reports where required.

When does the acceptance test occur?

Utilities may be descriptive around what stage the acceptance test can occur, with practical completion of various other on-site works a pre-requirement. Where specified, this detail is listed in a specification document or instruction issued directly from the approving authority.

Cause of Delays

Delays in the workflow when submitting acceptance inspections can occur due to:

  • The time it takes to supply the approving authority the specified video and associated report/s; or
  • In instances where a pipe does not pass the acceptance test, there will likely be some form of minor repair/maintenance required and a follow-up CCTV inspection to confirm any identified issues have been rectified. In most cases this will be jetting to remove construction debris/deposits, or patching a location with pipe wall damage

If the follow-up to a failed CCTV acceptance test is delayed due to the workflow that is setup between civil contractor, CCTV contractor, and reviewing engineer; the cost to the overall project can be significant. In some cases, this delay will fall on the critical path of other finalization works and negatively impact other teams working on the development project. VAPAR has specifically designed a workflow that ensures the time between the CCTV inspection and approval is minimized to reduce any unnecessary or costly delays. In instances that repair or maintenance is required, the details of this can be distributed to the required parties quickly.

deposits and debris in pipe

Figure 2- Deposits and debris that requires removal before acceptance

How can VAPAR assist in avoiding costly delays in your review and approval timeline?

Same day turn-around can be achieved with upload from site that only requires the video file and an internet connection to your internet browser. VAPAR’s AI processing time is measured in minutes, not days. Your reviewed inspection results can be shared in real time with clients you have invited into the VAPAR.Solutions platform in a structured library of current and past inspection projects.

Alternatively, you can choose to send your package of inspection results for the day, or week, as a pdf report set or spreadsheet summary. What does this mean in practical terms? Data and results (including access to the selected inspection video files) can be shared without the requirement for downloaded software or file sharing programs. The CCTV inspection videos, and associated results are available directly to your client in the method most convenient for your situation.

Keeping all your inspections organised and accessible

VAPAR’s cloud storage solution for inspections means cataloguing, finding, and viewing your past CCTV results is both user friendly, and eliminates the requirement for on-premises storage. No more lost files spread across different servers and cluttered folder structures. For utilities that would like to compare original acceptance inspections with end of defect-liability inspection, or condition assessment years down the line, this can be done directly from your internet browser by searching asset ID, or node, to bring up your matching results.

Image of VAPAR.Solutions

Figure 3- Searching past inspections of the same pipe asset

About the Author Mark Lee
waste water monitoring

Increasing the value of wastewater network monitoring

Increasing the value of wastewater network monitoring

Innovation is the key to delivering ever-increasing performance

Asset owners around the world are looking for innovative ways to deliver on the challenge of increasing wastewater network performance targets. With improved technology and the ability to handle large amounts of data, it’s become significantly easier to monitor flow and depth patterns, and highlight issues within a network that trigger a maintenance response prior to a flooding or pollution incident occuring.

waste water monitoring

Radar level and IoT telemetry device from Metasphere (Sense Level, ART Sewer)
Wastewater monitoring can generate a return on investment when they prevent flooding and pollution incidents.

Of course, there is no point in installing monitors for the sake of it, they should be positioned so that they have the greatest value. Having monitors in areas that don’t generate a return on investment is not prudent, therefore knowledge of current system performance and planning is required to determine the optimal locations that will provide a positive return when installed in locations that are most likely to prevent flooding or pollution incidents. 

The most important part of the puzzle in locating monitors is to understand the characteristics of the most common failures within the network; blockages. A previous UKWIR project  identified the following: 

  • 20% of blockages reported over a year are repeats at property level and this increases to between 40% and 60% when analysed at the postcode level. 
  • The proportion of repeats increases to 30% and 70% at a property and postcode resolution respectively when there are 5 years of data available. 
  • Approximately 50% of postcodes and 4% of properties have suffered 1 or more blockages over a 9-year period, this reduces to 23% of postcodes and 1.2% of properties suffering repeat blockages over the same period. 
Picture of sewer blockage

Analysis of historic blockage data indicates blockages repeat at the same location over time.

This analysis shows repeat blockages happen at the same location and that if monitors are located correctly, they can be effective in preventing major incidents. 

 The report also identified the most common causes of blockages: high density of interceptors, high densities of FOG (fats. oils & grease) generating properties, older properties, terraced / high rise properties, small diameter sewers and lower affluence. 

 This suggests that taking remedial action such as removing interceptors, root cutting, repairing structural defects and educating customers about the use of FOGs and wet wipes would mitigate the probability of repeat blockages. Fixing the root cause will prevent having to constantly reattend to carry out blockage clearance maintenance, which causes inconvenience for the customers and increases operational costs. 

 In a perfect world asset owners would repair and replace all the defects in a wastewater network. The reality of course is there is no bottomless pit of money for this activity and funding will continue to be challenged given the current focus on the affordability of utility bills.  

Person calculating his expenses

The affordability challenge associated with utility bills means there will never be sufficient funding to repair all defects on the network.

Repairs are not always practical or cost effective

This is where asset management comes in and provides us with the capability to effectively balance the cost, risk and performance triangle depending on the objectives of the asset owner. For example, In the case of complicated wastewater networks that may run beneath buildings with a flat gradient that increases the blockage probability, then the implementation of a proactive cleansing programme is likely the best approach to balance cost, risk and performance.  The use of monitoring in these situations allows the proactive maintenance costs to be optimised and ensure cleansing is only completed when it is required. 

Cost, risk and performance triangle

Asset Management provides the capability to balance the cost, risk and performance triangle to deliver the asset owner’s objectives.

Alternatively, the installation of a monitor where roots have been identified or where a partial collapse has occurred is unlikely to balance the triangle correctly. It will likely be more efficient to mitigate the root cause (e.g. cut out the roots or repair the collapse) compared to monitoring the location.  

Data is key to making informed decisions

The ability to adapt the correct balance of cost, risk and performance for each scenario is based on having the right data available to understand the root cause of a flooding or pollution location.  Using CCTV pipe inspection data provides the ability to understand the root cause and enables monitors to be installed at locations where they can generate the greatest Return on Investment (ROI).  The historic challenges with CCTV pipe inspection data have been its cost (e.g. it is not cost-effective to survey the entire network) and the ability to provide the outputs in a format that allows good investment decisions. 

 VAPAR uniquely combines Artificial Intelligence, the latest software capability and human input, reducing the cost of CCTV pipe inspections and making the outputs more accessible to decision-makers. Reducing the cost of CCTV pipe inspections makes it more economical to either complete CCTV pipe inspections prior to installing a monitor or use existing inspection data as part of the monitoring decision-making process. A great example of making the CCTV pipe inspection data more accessible is the visualisation of the survey results via a GIS, where the defect locations can be understood relative to the proposed monitor location on the pipe network. 

Pipe network and defects seen on GIS using VAPAR

VAPAR’s capability to visualise CCTV pipe inspection data allows monitoring locations to be identified that will deliver the greatest ROI.


It is fundamental for Asset Managers to look at alternate and innovative ways of managing pipe networks if they are to deliver the increasingly challenging financial and performance targets. The use of network monitoring provides one of these innovative ways, however, it will not provide a ‘Silver Bullet’ in isolation.  The use of VAPAR alongside monitoring will allow CCTV pipe inspection data to inform the decision-making process on where to install monitors. Ultimately this will balance cost, risk and performance and ensure the return on investment from monitoring is realised. 

Nathan Muggeridge - Author
Enlight2786 (002)

Local Sewer History Finds

Local Sewer History Finds

Keeping an eye out for local sewer history finds

Most major cities had their first sewer infrastructure constructed centuries ago. While much of the original networks are either long gone or buried deep underground, if you do a little research and keep your eyes open you’ll likely find some interesting structures that formed part of the original systems. In some cases, these will be decommissioned, others are still in services hundreds of years after they were built.

Sewer aqueduct spanning Johnstone's Creek (Annandale, Sydney)

Finding a piece of Sydney’s sewer history

Out on a recent morning jog in Annandale, I came across a sewer aqueduct that was partially enveloped by the canopy of a large fig tree. Reading the faded plaque on one of the concrete arch supports and reading up on its history, it was interesting to learn about the important role this structure played in the early Sydney sewer network.

The Johnstone's Creek Aqueduct

Designed by Prussian engineer William Baltzer and constructed by Carter, Gummow and Forest in 1896, the aqueduct contains 8 primary arches and has a total length of 281m. It was the first use of reinforced concrete for a large structure in Australia. This very new construction technique of the time was under patent and known as the Monier system. The historical significance of the Johnstone’s Creek aqueduct has led to it being listed on the NSW State Heritage Register.


Early example of reinforced concrete in Australia

Transporting sewage to Bondi

The separation of the Sydney’s combined stormwater and sewer pipework began in 1887, and by 1889 the Sydney sewer network had reached 140km of pipe and was servicing close to 25,000 properties across the inner city. With this flow discharging into the harbour, construction of more sustainable options had been underway for some time. Construction of the Bondi Ocean Outfall and Botany Sewage Farm was completed in 1889 and allowed for further expansion of Sydney’s sewer network. 

This included the Northern Main Sewer which would service the growing population in Annandale and Balmain and transport flow to a main line junction at the corner of Parramatta Rd and City Rd, then all the way through to Bondi. This extension required crossing both Johnstone’s Creek and White’s Creek with the construction of aqueducts the most suitable design option of the time.


Could reinforced concrete be trusted?

In the late 19th century, the idea of using concrete for such a large structure was not without detractors. The original Public Works Department design called for a brick arch construction and the submission for this new design and material had initially been rejected due to its experimental nature and unproven history. However, support from Robert Hickson (Under-Secretary for Public Works) was interested in trialling the use of reinforced concrete and what was an innovative idea at the time. The Monier design delivered spans that could be 50% larger than brick, and the total cost of the project was quoted as 20% cheaper – it received the go-ahead for construction after test arches were loaded to failure at Burwood with positive results.

Looking west from Glebe to Annandale showing construction of Johnstons Creek Sewer Aqueduct. (City of Sydney Archives)

The rest is history

It didn’t take long before the advantages of reinforced concrete led to a rapid increase in use for a wide range of structures. The first reinforced concrete water reservoir was built in Kiama just a few years later in 1899. The Annandale Aqueduct has certainly stood the test of time, it required only minor maintenance in its first 90 years of service – far exceeding the 3-year guarantee period. The flume was eventually plastic lined in the 1980s and the arches underwent repair and protection works in 1996. 

Still interested in more of the aqueduct’s history?
Well, there was some controversy!

Like any good historical story, the construction was not without controversy. A Royal Commission was held in 1896 and ran for over a year. It was based around accusations of favouritism, contract violations, and defective work. This was not assisted by the fact that at the time William Baltzer suggested the alternate design he was working as a draughtsman in Sewerage Construction Branch of the Public Works Department while also on retainer as an engineer for Carter, Gummow and Forest who were awarded the contract. Despite the large furore and public investigation, the final report fully exonerated Hickson, Baltzer and others involved. It even went as far as finding that some of the allegations appeared frivolous and not founded in truth. As difficult as this must have been for the engineers and others involved in the commission so soon after construction, it is the detailed record of the commission that has provided such informative history and detail about the project from inspection to completion. It was the commission proceedings themselves that meant this significant construction achievement become one of the best documented contracts of the era.

Extract from the Public Works Inquiry Commission

VAPAR.Solutions is designed to process and score video footage from a wide variety of camera systems, providing a single cloud-hosted location for all your inspection videos, images, reports and decisions.

About the Author Mark Lee

Opportunities to improve the UK pipe inspection standard (MSCC5)

Opportunities to improve the UK pipe inspection standard (MSCC5)



If you work within the UK water industry, you will be very aware of the MSCC5 (Manual of Sewer Condition Classification Fifth Edition). The first edition dates back nearly 40 years now, and in that time, many hundreds of thousands of miles of sewers and pipes by thousands of different contractors of all shapes and sizes have used the code to create a standardised output.


Is history holding back the future?

The Water Research Centre (WRC) first published MSCC back in 1980, and since then, other countries have adopted the idea behind a standard. This led to the creation of the European Standard  BS EN 13508-2:2003+A1:2011, which has allowed the different codes to use a common language. 


This alignment now presents a challenge with updating MSCC so it can keep pace with the technological changes. The need to align with the European Standard means many stakeholders will need to agree to any changes. However, there is a real need to update the standard, given that the current manual is still referring Cathode-Ray Tube (CRT) screens and their calibration. Is there anyone out there using these screens now? 


MSCC5 references the calibration of Cathode-Ray Tube screens. Does anyone else still use these screens?

The first opportunity to improve the standard is to consider what the future of pipe inspecting coding might look like and how MSCC can support the future. We feel that using AI and modern software techniques is the first step in modernising a sector that has not changed significantly in the last 40 years. 

car manufacturing with humans

Can the pipe inspection industry be modernised to deliver the benefits generated by the latest manufacturing plants?

How could we look at things differently?

So, what could a new coding standard look like in 2022 if we were designing it from scratch? If you look at computer software these days, it is a lot simpler than it used to be. Less is more now, and even the most complicated programmes have simple user interfaces to help speed up workflow and productivity. Gone are the days of needing to install desktop software and then updating it physically.

So how can this be applied to sewer surveying and classification, given that there are different types of users, from Water companies to small drainage contractors?


We need to think about why we are doing the survey and what is the result we want. The purpose of the standard is all about making an informed decision about investment in repair, maintenance, or renewal in line with its condition, serviceability, and budget available. Does the current coding standard meet the requirements? If yes, does it do it with simplicity in mind? This factor is essential when training people on how to code and survey? With so many codes and conditions to learn, this can extend training requirements and take years for operatives to gain all the experience needed to code the surveys to the exacting standards. Are contractors doing this, and is it possible to audit it accurately – probably not! 


By simplifying and determining the key elements that make up the investment decision, we could remove a lot of unnecessary work and time and use enhanced technology to fill in the gaps speeding up workflow and productivity and saving money. The delivery of this outcome could start with a single document containing the coding and scoring requirements. Currently, MSCC5 includes the codes, and the Sewer Risk Manual holds the scores to determine the condition grades that typically drive the investment need.


Coding observations

Do the current set of codes consider all likely defects on the network? Is coding of infiltration, H2S attack and Hydraulic overload accurate and in a way that informs decisions on the action necessary. We don’t currently have a condition grade that reflects the degree of infiltration associated with an asset.


Abandoned surveys require a comment in the remarks section to explain the root cause for the survey being abandoned. This approach is not helpful when you own a survey company and are looking to minimise the number of abandoned surveys and increase your productivity. How do you determine the value of providing the crews with longer cable lengths to minimise the number of ‘out of cable’ abandonments? In other countries, they have specific abandoned codes related to the defect before. For example, the Australian manual has ‘Survey Abandoned Collapsed Pipe’.

pipe inspection abandoned

How many abandoned surveys occur due to insufficient cable length? 

 Open and displaced joints always cause much debate and can be confusing 5-10% of diameter gets a score of 40, but 1.5 pipe wall thickness receives a score of 2. Typically, a pipe wall thickness equals 10% of the internal pipe diameter, so how can this be made more consistent?

Condition Assessments

We have a situation where we have two different types of condition assessment criteria in the UK. There are two scoring systems; the DRB Drain Repair book grades A, B & C (for domestic properties) and the SRM (Sewer Risk Management grades 1-5) on some software systems. Whilst they map against each other, it seems questionable to have two different approaches. It is essential to have accurate data to make informed decisions, and having one standard will make that accuracy more consistent. This further help simplify the training and reduces the costs for survey company owners.


Furthermore, is it also possible to be more scientific about the likelihood of further deterioration or collapse? Given that we have years of data, is it possible to develop a more accurate way of assessing risk on specific pipe lengths? Could this allow us to plan repair and maintenance more productively and head off issues at an earlier stage with a more cost-effective repair? We suspect the disparate data storage capability of the incumbent software applications for pipe inspection coding means this will be difficult. However, VAPAR’s central database of pipe condition assessments allows this type of data to be easily accessed and could be the key to unlocking a faster and more cost-effective solution to surveying and condition assessment.

Final thoughts

Technology plays a massive part in all our lives; whilst CCTV camera technology has advanced exponentially over the past ten years reporting systems have remained static. The traditional processes are still heavily manual and require extensive training and experience to keep the data collected consistently. But are we now at crossroads in terms of the old and the new?

VAPAR‘s AI platform is now able to generate MSCC5 compliant outputs. The development work to comply with MSCC5, plus the standards used in Australia, the United States and New Zealand, has provided us with a unique perspective.

VAPAR’s modern and unique capability to combine AI and human inputs to produce a fast and accurate output provides an opportunity to match the latest CCTV camera technology. Updating the MSCC standard is one part of the puzzle that will significantly improve how we do things for the customers using piped networks.

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Vapar provides the capability to combine AI and human inputs to produce a fast and accurate output and provides an opportunity to match the capability of the latest CCTV camera technology.

manhole cover in slovokia

Basics of Sewer Manholes

Basics of Sewer Manholes

Picture of sewer manhole

What are manholes?

Sewer manholes or also called maintenance holes are formal access points within the sewer pipe network that provide maintenance teams a chance to get access to maintain the sewer pipe network. They can come in many different shapes and sizes depending on how deep they go into the ground and what the surrounding ground conditions are like.

Why do you need manholes?

Once a blockage or a break in the sewer pipe is confirmed through a CCTV inspection, maintenance teams need to get access to remedy the issue. Without the presence of manholes, any remediation would be complicated and expensive.

Where can you find manholes?

The spacing of the manholes depends on a couple of factors. If a sewer pipe is running in a straight line in an area where access is not an issue, then they are usually placed every 80-100 metres (260-330 feet) along a sewer pipe. This spacing is determined by the practical length of water jetting equipment to reach the full length of pipe, regardless of whether the water jetting was done from the upstream manhole, or the downstream manhole.

That being said, manholes can also be built at shorter or longer lengths. For example, if the pipe needs to have bends in it, the design engineer might want to install extra manholes to account for the risk of blockage at the change point in the flow of sewage.

Manholes can also be placed within the network at irregular locations when the pipe network runs under a highly urbanised area. Placing manholes in the middle of roads, or in the middle of someone’s property is not advisable.

There are serious safety issues with placing manholes too close to live roads and having a manhole under a concrete floor slab doesn’t really serve anyone either. For this reason, the configuration of the network and the spacing of manholes might vary to account for the above ground infrastructure.

Drain spotting

You can identify the presence of manholes by the manhole covers on roads, footpaths and even in parks. The manhole covers themselves can come in many different shapes and sizes also, although most are round. They are usually made of metal to withstand the weight of heavy vehicles.

There is a great #drainspotting hashtag that you can browse to see what others have contributed from all over the world. Perhaps on your travels, you might feel compelled to contribute some interesting manhole designs and locations and help educate others on the weird and wonderful world of our underground sewer networks.

sewer points
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IN-R Drone

Sewer Camera – An explanation of the different types of camera hardware

Sewer Camera – An explanation of the different types of camera hardware

The inspection of sewer and stormwater networks is commonly completed using a camera that records video footage from the inside of underground pipes also called the sewer camera. The photos and videos collected during a pipe inspection can be used to assign a condition grade to pipes through the identification of structural and service defects. Councils, municipalities, and water authorities use these condition grades to prioritise pipe maintenance (e.g., clearing roots and debris) and repair (e.g., patches and lining). 

Access to pipes is usually obtained through maintenance holes or pits which can be located within roads, kerbs, public space, and private property.

A variety of different camera equipment is available to record video footage for defect analysis and scoring. Common sewer camera types include:

Crawler Cameras

Crawler cameras are robust remotely controlled inspection robots that traverse through a pipe on wheels. They typically have a strong light source to illuminate the inside of the pipe and are connected via a cable to a vehicle on the surface that supplies power and transmits the video back to a vehicle computer for recording. The robot is controlled by an operator on the surface who directs the crawler’s progress through live vision fed back to their computer monitor. They can adjust for speed and direction, and often have the ability to pan, tilt and zoom the camera lens; leading to the term PTZ camera (they are also called tractor cameras in some regions). Crawler cameras are the most common type used for pipe network inspections throughout the world.

Fixed Zoom Cameras

Fixed zoom, or pole cameras, do not need to travel along the pipe to collect video footage. They consist of a fixed high-definition camera head attached to a pole that is lowered from the surface to the base of the pipe at surface entry locations. Using a combination of strong zoom, focus adjustment, and lighting; a video is recorded as the camera zooms in and the field of vision extends through the pipe from chainage zero to the end of pipe or bend. With a combination of optical (20-40x) and digital zoom (10-15x) they provide a fast and robust way to collect a condition overview of a network.

Image of pole camera for sewers

Push Rod Cameras

House connection branches or sewer laterals present unique challenges when collecting condition footage or diagnosing a problem. Their small diameter and frequent bends mean the larger camera hardware is unable to enter and travel through these smaller lines (typically < 150mm diameter). Push rod cameras are designed for tough and tight conditions. Appearing as a coiled cable on a real with a slim camera head, they can be inserted and controlled manually with imagery fed back to a control unit. The use of skids is sometimes employed to keep the camera head and vision steady and centred.

Pushrod camera for sewers

Inspection Rafts

For large pipes that cover long distances, an inspection raft may be the only choice to collect imagery from within a pipe. These are often used for outfall tunnels where they can be sent downstream and caught with a hook or net at location that could be many kilometres further down the pipe. They are usually designed to stay upright and balanced.

Image of push raft camera for sewers

Drone Cameras

With rapid advancement in UAV technology, the industry has seen an increase in the use of drones for pipe inspection over the last few years. Drones have some distinct advantages in certain situations, including; large pipes with high flow where a crawler may not be able to enter and raft would traverse along the pipe too quickly, and longer pipe inspections where equipment weight or cable length is prohibitive. It will be interesting to see how this technology develops and if it becomes a more mainstream option for pipe networks.

IN-R Drone

Manhole / Maintenance Hole Cameras

There are now a variety of dedicated cameras available for collecting photos, videos, and 3D scans of the vertical shaft that leads down to the benching and pipe channel. In the past this has been completed by visual surface or confined space entry inspection, using a regular camera, or with a crawler as it is lowered down to complete the main pipe inspection. Newer camera technology has been specifically designed to collect more detailed information with much higher resolution than ever before.

Manhole maintenance camera

Jetter Nozzle Cameras

Jetters can be used by operators to clear sediment, obstructions, fats, oils, grease, and roots from pipes. Some hydro jetters on the market include a nozzle camera that can be used to help guide the camera through the pipe, locate specific issues and even steer into lateral pipes. The camera is also able to collect video footage following its cleaning run through the pipe to collect information on the effectiveness of the clean and provide an indication of the condition of the cleaned pipe.

Image of Jetter nozzle camera for sewers

VAPAR.Solutions is designed to process and score video footage from a wide variety of camera systems, providing a single cloud-hosted location for all your inspection videos, images, reports and decisions.

About the Author Mark Lee
Image of a CCTV pipe inspection camera on a race track

Let’s race, CCTV pipe inspection cameras!

Let’s race, CCTV pipe inspection cameras!

And why not. As human beings, we desire to race everything else in our lives; cars, motorbikes, lorries, boats and even tractors! So why not race pipe inspection cameras? 

What’s the current speed limit?

Anyone working in this area will know that the specification for inspections of sewerage and drainage networks will limit the camera speed to 0.1 or 0.2 m/sec (0.33 or 0.66 ft/sec) depending on the pipe size. Some of you think even achieving something close to this speed can be challenging given the need to negotiate roots, intruding laterals, debris and Weird Things in Pipes ( #weirdthingsinpipes). Additionally, there’s lots of time spent travelling to an inspection site, finding the asset, setting up traffic management, entering the asset data on the title screen, etc. For that reason, pipe inspection productivity is nowhere near the 2,880 m (9449 ft) per day that could be achieved by a camera travelling down a pipe at 0.1 m/sec (0.33 ft/sec) pipe for 8 hours.

What does that data say about actual camera speeds?

We were keen to understand the average speed of a pipe inspection camera and the data captured in the VAPAR.Solutions platform provides the ability to do this. The platform holds a vast array of data that offers the opportunity to generate insights, including the ability to estimate the average time for a camera to travel through a pipe and complete an inspection. A random sample of surveys from the UK, Australian and New Zealand markets indicates the average speed is 0.13 metres per second (0.43 ft per second), with an 80-second mobilisation/demobilisation time for each survey. The analysis uses inspection footage durations and has removed the supersonic and snail-paced outliers.

Why increase camera speeds?

This analysis demonstrates that the markets generally comply with the specification, so why would you want to increase camera speeds? In addition, we have shown that the time inspecting the pipe accounts for only part of the working day, with time spent on other supporting activities. As with all outstanding racing achievements, not one change leads to success, but a combination of small-time savings creates a race-winning performance. This is generally known as Marginal Gains: small incremental improvements in any process, which, when added together, make a significant improvement (see Remember, you only need to be 0.001 seconds ahead of second-place to be the winner, and the same goes for any commercial analysis of a tender.

How can we increase pipe inspection camera speeds? 

It is not about running the camera through the pipe as fast as possible. The purpose of the inspection needs to be maintained; identify defects or characteristics that will prevent the pipe from providing the required service levels. The current specification speeds allow the camera operator sufficient time to identify defects. However, the advent of VAPAR’s AI-assisted defect coding means you don’t have to rely on the camera operator to identify the defects. The AI technology can support the analysis of inspection footage captured at speeds higher than the current standards while providing high-quality output. Additionally, the move to off-site coding means the camera operator can focus on the quality and speed of the pipe inspection footage and is not distracted by the need to code the surveys simultaneously. For example, you don’t see a Hollywood film studio trying to produce the final film while on set!

So, who is up for a bit of pipe inspection camera racing?

About the Author description - Nathan Muggeridge BDM UK and EU - VAPAR

Read more about how VAPAR is increasing the efficiency and value of underground pipe inspections here.