Trenchless sewer repair field guide: pipe lining vs pipe bursting

Trenchless sewer repair, and what it actually means

Trenchless sewer repair is rehabilitating or replacing a buried sewer with little or no digging. Instead of excavating the whole run, opening a long trench, replacing the pipe, and putting back the parking lot or the lawn, you work through the existing pipe from a cleanout or a small pit at each end. The pipe stays in the ground, or a new one takes its place along the same path, and the surface above it mostly does not get touched.

The appeal is the restoration, not the pipe. On a real job the cost is rarely the pipe itself. It is the asphalt, the slab, the landscaping, the traffic control, and the days the site is torn up. Trenchless cuts most of that, which is why it wins under a finished lot, a building, a road, or an operating site where a trench is a shutdown. Done right it is faster and far less disruptive than open-cut, and the line comes back stronger than the one it replaced.

It is not magic, and it does not fit every pipe. The line has to qualify for the method, and that is the whole game. A pipe that is mostly sound but cracked, rooted, or corroded is a lining candidate. A pipe that is collapsed, badly back-pitched, or undersized is a bursting or a dig. A pipe with a belly is a dig no matter what anyone selling a liner tells you. The building sewer guide covers how the lateral was built and graded in the first place, and the drain-cleaning guide covers the camera and the cleaning that come before any repair.

Why diagnose with a camera and locate before you pick a method?

You cannot pick a trenchless method without a camera inspection and a locate, full stop. Every other decision in this guide hangs on what the line actually is, and the only way to know is to put a camera down it and read the pipe. Anyone quoting a lining or a bursting job off a backed-up drain and a hunch is guessing with the owner's money.

The camera tells you the things that decide the method: where the defect is and how far down, what is wrong, whether the pipe is cracked, offset, rooted, corroded, or collapsed, what material it is, where the bellies and the sags sit, and where every lateral ties in. The locate, run off the camera head's sonde, puts those findings on the surface as a flag and a depth, so a defect at 60 ft becomes a marked spot instead of a guess. The drain-cleaning guide covers the camera and the locate as a diagnosis in detail; here it is the gate every method passes through.

Two findings flip the whole plan. A belly takes lining off the table for that section, because lining preserves the sag. A collapse takes lining off the table too, because there is no host left to line. Find those on the camera and you have just saved yourself a failed liner and a callback. Skip the camera and you find them the expensive way, after the resin has cured over a problem it could never fix.

The failures that drive a repair, and what trenchless can fix

Sewers fail in a short list of ways, and which one you have decides whether you line, burst, or dig. Roots get in through joints and cracks and net the flow. The pipe cracks or breaks from soil load, settlement, or age. Joints offset or separate as the ground shifts, leaving a ledge or a gap. The pipe corrodes, which is the story of old cast iron tuberculating shut, clay going brittle, and Orangeburg, the old tar-paper pipe, delaminating and deforming. And the grade goes wrong, which is the belly, the back-pitch, and the sag.

Lining handles the first group well. CIPP seals cracks, breaks, offset and separated joints, root intrusion, and corrosion, because it builds a continuous new wall inside the old one with no joints for roots to enter and no rough corroded surface to snag. A pipe that is broken but still in line and holding its shape is exactly what a liner is for.

What trenchless cannot fix is geometry. A belly is a grade problem, and neither lining nor bursting restores grade, so a sag stays a sag. A fully collapsed pipe has no host to line, so it is a burst or a dig. An undersized pipe that needs more capacity cannot be made bigger by lining, which only shrinks it, so that is a burst with an upsize or a dig. Read the failure first, then the method follows from it.

What is CIPP pipe lining?

CIPP, cured-in-place pipe, is a resin-saturated tube installed inside the old pipe and hardened in place to form a new pipe within the old one. The tube is a felt or fiberglass liner, it gets wet out with a thermosetting resin, it goes into the host pipe soft, it is pressed tight against the old wall, and then it is cured until it sets into a rigid, jointless pipe bonded to the inside of the host. When it is done you have a structural pipe inside the structural pipe, with a smooth bore and no joints.

It is the most common trenchless rehab method for a reason. It needs no continuous trench, it follows bends, it spans cracks and offset joints and rooted joints in one continuous wall, and it works in pipe from small laterals up to large mains. For a sewer that is failing at the joints and the cracks but still holds its line and shape, CIPP is usually the cleanest fix on the table.

The cost you pay is a little diameter. The liner has a wall thickness, so the finished inside diameter is slightly smaller than the host pipe. On a sewer that loss is usually more than made up by the new smooth bore, which flows better than the old rough, scaled, or root-snagged surface it replaced. The liner needs a host that is still mostly intact, though. It is a pipe within a pipe, and it needs the old pipe to press against and follow. Take the host away, as in a collapse, and there is nothing to line.

The CIPP process, step by step

The lining itself is fast, but the prep is most of the work, and skipping it is how liners fail. The line gets cleaned first, because the liner bonds to and presses against the host wall, and it cannot do that through grease, scale, or roots. You jet and descale and root-cut the host pipe until the wall is clean and the bore is open, which is the cleaning the drain-cleaning guide covers, run to a higher standard because a liner is going on top of it.

Then you camera and measure. You confirm the host is sound enough to line, you measure the length and the diameter so the liner is cut and sized to the run, and you mark every lateral so you can find them again after the liner covers them. The liner gets wet out with resin, the felt or fiberglass saturated through so there are no dry spots, which is the step that decides the finished strength.

The wet-out liner goes in one of two ways. Inversion turns the liner inside out with water or air pressure and rolls it into the pipe resin-side-out against the host wall. Pull-in-place drags the liner in on a cable and then inflates a bladder to press it out against the wall. Either way the liner is held inflated and tight while it cures. After cure, a remote robotic cutter goes back in and reopens each lateral that the liner sealed over, and a final camera run confirms the wall is tight, the laterals are reinstated, and the bore is clean end to end.

Cure types: ambient, hot water and steam, UV

The cure is what turns the soft resin-soaked liner into a hard pipe, and it comes in three families. Ambient cure lets the resin set on its own over time at the temperature it finds in the pipe, which is the slowest and the most weather-dependent. Heat cure circulates hot water or controlled steam through the inflated liner to drive the resin to set faster and more evenly. UV cure pulls a light train of UV or UV-LED lamps through a fiberglass liner and cures it with light, which is the fastest and gives the tightest control over the cure.

The trade-off is speed and control against cost and the resin chemistry. Ambient is simple and cheap and slow, and a cold pipe drags the cure out. Steam and hot water are faster and the standard for a lot of mainline felt-liner work. UV is the quickest and the cleanest cure, common on glass-reinforced liners, and it lets you watch and meter the cure as the train moves, but the equipment and the liner cost more.

The cure parameters are not yours to invent. The time, the temperature, the pressure, and the light speed are set by the resin and the liner manufacturer for the specific system, and they are what the design and the spec hold you to. Run the manufacturer's cure schedule for the system you are installing. A liner cured short or cold is a soft pipe that fails early, and the camera will not always show it the day you finish.

Sectional and point repairs: the spot fix

A sectional repair, also called a point repair or a CIPP patch, is a short liner that covers one defect instead of the whole run. A short resin-saturated liner is positioned over the bad joint, the crack, or the offset on a packer or a bladder, pressed out against the host wall, cured, and the packer is pulled out, leaving a structural patch over that one spot. It is the spot fix to the full-length liner's whole-pipe fix.

It earns its place when the pipe is sound except for one defect. A single cracked joint, one offset, one rooted connection in an otherwise good clay line does not need a full liner end to end. A point repair seals the one problem at a fraction of the cost and the disruption, and it does not cross or seal the laterals the way a full liner does, so there is no reinstatement to do unless the defect is at a connection.

The judgment is how many defects you have and how the rest of the pipe looks on the camera. One or two isolated defects in a sound pipe are point-repair territory. A pipe with bad joints all down the run, or general corrosion the length of it, is a full-length liner, because patching it spot by spot costs more than lining it once. The camera, again, is what tells you which case you are in.

What is pipe bursting?

Pipe bursting replaces the old pipe instead of lining it. A bursting head, a cone-shaped tool larger than the old pipe, is pulled through the line, and as it goes it splits the old pipe and shoves the pieces out into the surrounding soil while pulling a new pipe in right behind it. The old pipe is destroyed and stays in the ground as fragments. The new pipe takes its place along the same path. It is replacement without a continuous trench.

The new pipe is almost always HDPE, high-density polyethylene, fused into one continuous jointless length on the surface before it is pulled in. That fused HDPE string has no joints in the ground for roots or infiltration to ever find, which is part of why bursting makes such a durable replacement. Static systems pull a head on rods or a chain with a heavy hydraulic puller; pneumatic systems hammer a head forward while a winch keeps tension. Both do the same job: break the old pipe out, pull the new one in.

The thing bursting does that lining cannot is replace a pipe that has nothing left to line, and change the size. Because the head displaces the old pipe outward, you can pull in a new pipe the same size or a size or two larger, an upsize, which lining can never do. So a collapsed pipe, an undersized pipe that needs more capacity, a pipe too far gone to host a liner, those are bursting jobs. It needs an entry pit and an exit pit, and it needs room around the pipe for the old fragments to push into, which is the catch covered below.

When do you burst and when do you line?

Line when the host is mostly intact. Burst when it is not, or when you need it bigger. That is the decision in one sentence, and the camera is what answers it. CIPP needs an existing pipe that still holds its line and its shape to press the liner against and follow, so a cracked, rooted, offset, or corroded pipe that is still basically a pipe is a lining job. Bursting needs no host at all, because it replaces the pipe, so a collapsed, crushed, or badly deformed pipe that cannot host a liner is a bursting job.

Capacity and grade push the call further. A pipe that is undersized for the load cannot be fixed by lining, which only makes the bore smaller, so if you need more flow you burst and upsize. Bursting also gives you a fresh jointless pipe, which some owners want even where a liner would technically work, especially on a line that has been a chronic problem.

Here is the honest limit that catches both methods. Neither lining nor bursting fixes a belly or a back-pitch, because neither one restores grade. Bursting pulls the new pipe along the same path as the old one, sag and all, so a bellied pipe burst comes back as a bellied new pipe. If the camera shows a sag holding water, that section is an excavation to re-grade, no matter which trenchless method you were hoping to use. Do not let a method preference override what the grade is telling you.

Slip lining: the older method and the diameter you give up

Slip lining is the original trenchless rehab, and it is the simplest one: you push or pull a new, smaller pipe inside the old one and grout the space between them. No resin, no curing, no inversion. A new HDPE or fiberglass pipe slides into the host like a sleeve, the annular space gets filled with grout to lock it in and carry the load, and you have a pipe inside a pipe by the most direct means there is.

The cost is diameter, and more of it than CIPP. The new pipe has to fit inside the old one with clearance to slide and room for grout, so it ends up meaningfully smaller than the host bore. On a line that had capacity to spare, the smooth new pipe often carries as much flow as the old rough one despite the smaller diameter, so the loss is tolerable. On a line that was already tight, slip lining can cost you more capacity than you can afford, which is why CIPP and bursting have taken over most of the work where diameter matters.

It still has a place. On a large-diameter line with plenty of spare capacity, where a continuous new pipe can be pulled a long way and grouted, slip lining is fast, cheap, and proven. It is a method to know and consider, not the default. For most building and site laterals where the diameter is already at the minimum the grade can hold, the diameter loss is the reason you reach for CIPP or bursting instead.

The belly: the limit trenchless will not cross

A belly is a sag in the line where the pipe dropped below grade and now holds standing water, and it is the one failure trenchless cannot fix. Lining a belly preserves the belly. The liner cures to the shape of the host pipe, sag and all, so you get a smooth new pipe with the same low spot holding the same water. Bursting a belly pulls the new pipe down the same sagged path, so you get a new pipe with the same sag. The grade is wrong, and no method that works inside or along the existing path changes the grade.

This is the hard sell and the honest one. A contractor who lines over a belly has taken the owner's money to preserve their problem, and the chronic slow drain comes right back because the water still pools in the low spot and the solids still settle. The camera shows the belly as the lens going underwater and staying there across the sag in a line that should be draining. When you see that, the conversation changes from method to excavation.

Fixing a belly means digging. You excavate the sagged section, re-lay it to grade on properly compacted bedding, the way the building sewer guide covers, and tie it back in. Sometimes that is a short selective dig in the middle of an otherwise trenchless job, which is fine and far cheaper than open-cutting the whole run. Say it plainly to the owner: the rest of the line can be lined or burst, but the belly is a dig. State the grade limit firmly, because pretending otherwise is the most common way trenchless gets a bad name.

Access: the pits for bursting, the cleanout for lining

Trenchless does not mean no digging at all. It means minimal, targeted digging instead of a continuous trench, and the access you need depends on the method. Lining usually works through existing cleanouts or manholes, or through one small access pit at an end, because the liner is fed in from one point and run down the pipe. On a building lateral that often means the existing cleanout at the building and the one at the property line are all the access you need.

Bursting needs two pits, an entry pit and an exit pit, one at each end of the run being replaced. The new fused HDPE pipe is pulled in from one pit and the puller sits in the other, and the pits have to be big enough to lay the pipe into the line and to work the head and the rods or chain. The fused HDPE string also needs a clear stretch on the surface to be assembled before it goes in, so you need staging room above ground as well as the two pits.

Count the access into the job honestly. Where the cleanouts are missing, undersized, or in the wrong place, lining may need a dig to create an entry point, and the building sewer guide covers where cleanouts should have gone. Where bursting needs a pit at a connection, a manhole, or a bend, that pit is a small excavation with its own restoration. Trenchless wins on restoration because the pits are small and few, not because there are none.

Reinstating the laterals after lining

When you line a main, the liner seals over every lateral connection along the run, because it is a continuous wall with no openings. So after the liner cures, each lateral has to be reopened, and this is a step that gets missed and turns into a backed-up house. A remote-controlled robotic cutter is sent down the lined main, located at each lateral, and used to grind a hole through the liner back open at the connection so the lateral drains again. A camera on the cutter watches the work.

The trick is knowing where every lateral is before you line, because once the liner is in, a blind lateral is sealed shut and the building it serves has nowhere to drain. This is why the pre-lining camera marks and counts every connection. Miss one, and the first you hear of it is a service call from a unit that suddenly will not drain, and now you are cutting blind to find a connection you should have logged.

On a single building lateral with no branch connections, there is nothing to reinstate, which is the simpler case. On a site or campus main with many laterals tying in, reinstatement is most of the finish work and most of the risk. Where a lateral connection itself is the defect, or where the robotic cutter cannot do a clean reinstatement, the connection gets excavated and rebuilt, which is a small targeted dig rather than a failure of the method.

Prepping the host pipe before you line it

A liner is only as good as the pipe it goes into, and the prep is where lining jobs are won or lost. The host pipe has to be cleaned to bare wall before the liner goes in, because the resin bonds to and presses against that wall, and it cannot bond through grease, scale, roots, or debris. You jet the line, you descale old cast iron back toward the metal, you root-cut every intrusion, and you flush the cuttings out, which is the drain-cleaning work taken to a lining standard.

Obstructions inside the pipe have to come out or get trimmed flush, not lined over. A protruding tap, a hammered-in old connection, or an offset ledge will print through a liner or stop it from seating tight, so the robotic cutter trims offsets and protruding taps smooth before the liner goes in. A liner pressed over a lump is a liner with a void behind it, and a void is where the new pipe fails first.

The pre-lining camera is the sign-off on the prep. You run it after cleaning to confirm the wall is clean, the bore is open, the offsets are trimmed, and every lateral is marked, and only then do you wet out and install. A crew that lines over a dirty or obstructed host to save an hour of cleaning has built a failure into the wall that the cure locks in permanently. Clean it right, then line it.

Resins, styrene, and curing safety

The resin is the chemistry that makes CIPP a structural pipe, and it comes in a few families. Polyester is the common, lower-cost resin for general sewer work. Vinyl ester carries better chemical and corrosion resistance for harsher waste streams. Epoxy is used where its bond and its lower shrinkage are wanted, often on smaller-diameter and pressure work. The resin chosen drives the cure method, the cure schedule, and the chemical resistance, and which one fits a given line is the manufacturer's and the designer's call, not a field substitution.

Styrene is the part to handle with respect. Many polyester and vinyl ester resins contain styrene, which has a strong odor and is a regulated chemical, and during installation and cure it can off-gas. That odor showing up in a building connected to a line being lined is a real complaint and sometimes a real exposure, so ventilation, controlling the cure, and managing where the off-gas vents are part of the job near occupied space. Styrene-free resins exist and are used where the odor or the exposure rules make them worth it.

Treat the curing and the resin handling as a manufacturer-governed safety task. The resin's safety data sheet, the ventilation and exposure limits, the handling of the uncured resin, and the cure conditions are set by the product and the regulations that apply, so follow the SDS and the manufacturer's procedure, and confirm the exposure and ventilation rules that the jurisdiction enforces. This is a place to defer to the chemistry, not to field habit.

Trenchless or open-cut: which one does the job?

Trenchless wins on restoration, time, and disruption. Open-cut wins when the pipe or the site rules it out. That is the comparison, and the cost that decides it is usually not the pipe but everything on top of it. Where the line runs under finished asphalt, a slab, mature landscaping, a road, or a building, a trench means tearing all of that out and putting it back, and that restoration often costs more than the sewer work itself. Trenchless skips most of it, which is why it is faster and cheaper on those sites despite a higher per-foot price on the pipe work.

Open-cut still wins in specific cases, and they are the ones trenchless cannot touch. A belly or a grade problem has to be dug and re-laid. A fully collapsed pipe with no host and no clear path may have to be excavated. A connection that has to be rebuilt, a pipe that has to move to a new alignment, or a deep service where the pits and the access cost more than a trench would, all of those can tip back to open-cut. And where the soil will not let the old pipe fragments displace, bursting can be a problem and a dig is safer.

The decision is per run, off the camera and the site, not a blanket preference. Price the restoration, not just the pipe, because that is the number trenchless actually saves. Then check the pipe against the method limits: grade, collapse, capacity, and access. When the pipe qualifies and the surface above it is expensive to restore, trenchless is the clear call. When the grade is wrong or the pipe is gone, the trench is honest and you dig.

Proving the repair: the post-camera and the air test

You prove a trenchless repair the same way you proved the pipe was bad: with a camera, plus a pressure or air test where the spec calls for one. After a liner cures and the laterals are reinstated, you run a post-installation camera end to end and look at the new wall. It should be tight against the host with no wrinkles, dimples, or lifting, every lateral cleanly reopened, no resin slugs or sags, and a smooth bore the full length. The post-camera is the acceptance, and on utility work it is documented to a standard inspection format.

Pressure and air testing back up the visual. An air test puts a low, measured pressure on the capped line and watches the gauge for decay, and a liner or a new burst-in HDPE pipe that holds confirms the repair is sealed against infiltration. On bursting, the fused HDPE can also be pressure-tested as a continuous pipe before and after the pull. The test that applies and the acceptance criteria are set by the sewer authority and the spec, so confirm which test and what pass mark before you finish.

Compare the post-camera to the pre-camera and keep both. The before shows what was wrong, the after shows it is fixed, and together they are the record the owner and the next crew rely on. A repair with no post-camera is a repair you cannot defend when the line acts up later, and on a line you cannot see, the camera is the only proof you have that the work held.

What you are rehabbing: clay, cast iron, Orangeburg, concrete, PVC

The host material shapes the repair, because each one fails its own way and takes a method differently. Vitrified clay is the old workhorse: strong in compression, brittle, and it fails at the joints and as cracks, which makes it a strong lining candidate when the pieces are still in line. Cast iron corrodes from the inside, tuberculates, and thins, so it has to be descaled and judged for remaining wall before lining, and a wall that is too far gone is a burst instead.

Orangeburg is the problem child. It is a bituminized fiber pipe, basically tar-impregnated wood pulp, used for decades mid-century, and it does not so much crack as delaminate, blister, and deform into an oval until it closes. An Orangeburg line that is already deforming has often lost the round shape a liner needs, so it is frequently a bursting or a full replacement job rather than a lining one. Find Orangeburg on the camera and plan to replace it.

Concrete and PVC round it out. Concrete and reinforced concrete sewers corrode from sulfide attack at the crown on the larger mains and can be lined or rehabbed, often with the heavier liners. PVC is the modern pipe and usually fails from a belly, an offset, or a crush from poor bedding rather than from the material going bad, which means the fix is as often a grade dig as a liner. The material tells you what to expect; the camera tells you the actual condition. Match the method to both.

The 50-year claim, and what it actually covers

CIPP and HDPE replacements are commonly sold with a long design life, often cited around 50 years, and the number is reasonable for a properly installed system but it is a manufacturer and design figure, not a guarantee you should repeat as your own. The design life comes from the resin and liner manufacturer and the structural design done to the standard, and it assumes the liner was correctly sized, fully wet out, and properly cured. Quote it as theirs, hedged, and tie it to the spec and the warranty document, not to a number you made up on the truck.

What the long life depends on is the install, and that is the honest part to convey. A liner cured short or cold, a host that was not cleaned, a void behind the wall, a missed defect: those shorten the life regardless of what the brochure says. A fused HDPE pipe burst in is a jointless pipe with a genuinely long expected service life, but it too lives or dies on the fusion quality and the bedding it ends up in.

The warranty is a separate question from the design life, and owners conflate them. The contractor's workmanship warranty, the manufacturer's material warranty, and the design life are three different things with three different terms. Put the actual warranty terms in writing, point the design-life claim back to the manufacturer's data, and do not promise a number the product literature does not support. The pipe may well last 50 years. Whether you are on the hook for 50 years is a contract, not a property of the resin.

Permits, the AHJ, and the sewer authority

Sewer work needs permits, and a trenchless rehab is still sewer work in the eyes of the plumbing code and the sewer authority. The authority having jurisdiction, the AHJ, governs the permit, the inspection, and the acceptance, and on the public side the sewer authority controls anything that touches the main, the connection, and often the lateral out to the property line. Pull the permit and confirm the inspection points before you mobilize, the same as you would for an open-cut.

The connection is where the authority's rule is firmest. Where a burst or a liner reaches the public main, or where a lateral ties in, the sewer authority's standard detail and inspection govern how it is done and who is allowed to do it, and the building sewer guide covers the tap and the property-line responsibility split. Some authorities have specific requirements or approvals for CIPP and for the resins used near their system, so confirm what they accept before you order materials.

Locating still applies. Call 811 before any pit or excavation, and on a bursting job pay attention to the utilities near the line, because the bursting head displaces soil outward and can disturb a parallel utility too close to the path. The locate, the permit, the AHJ inspection, and the sewer authority's acceptance are all part of the job. Confirm each against what the jurisdiction actually enforces, because the requirements and the accepted methods vary by authority.

Trenchless under an operating site: data centers and campuses

The case where trenchless earns its keep most clearly is rehab under a site that cannot be torn up. A data center, a hospital, a campus, a distribution center: the sanitary load may be modest, but the surface above the line is a parking field, a road, a slab, or a secure operating area, and a long open trench across it is a shutdown nobody can afford. Lining or bursting the line from a couple of small access points keeps the site running while the sewer underneath it gets rebuilt.

Plan it around the site, not just the pipe. The access pits and the staging for a fused HDPE string need room and they need to sit where they do not block operations, the styrene off-gas from a resin cure has to be managed away from intakes and occupied space, and the work has to be sequenced so the line being rehabbed is out of service only when the building can spare it. On a critical site the coordination is the hard part, and the trenchless method is what makes the coordination possible at all.

The minimal-disruption advantage is real and it is the reason to reach for trenchless here even at a higher per-foot price. You are not paying to avoid digging a pipe. You are paying to keep the site operating, to skip ripping out and restoring the surface, and to compress a multi-week trench into a few days of pit work. Keep the records tight, because on a campus the next failure is somewhere on the same aging system, and a tool like FieldOS is built to hold the camera findings, the method used, and the as-built so the next rehab starts from what is known, not from a fresh camera run.

What to document

A trenchless repair that nobody recorded is a buried pipe the next crew has to rediscover with a camera. The record is what tells the owner and the next plumber what was wrong, what method fixed it, where the access and the connections are, and what the line still needs. Capture it per run, because a single job can be a liner here, a burst there, and a grade dig at the belly in between.

For each segment record the defect found on the pre-camera, the method used and why, the material and size of the liner or the new pipe, the resin and cure type for a liner, the access pits and cleanouts used, the laterals reinstated and where, any belly or section that was excavated and re-graded, the post-camera result, and the test that proved it. Note the limit too: if a belly was left for a later dig, or a lateral could not be fully reinstated, that belongs in the record so it is a known item, not a surprise.

Common mistakes

• Lining or bursting a pipe with a belly or bad grade, which preserves the sag instead of fixing it.
• Quoting and starting a repair with no camera and no locate, so the real defect and the laterals are unknown.
• Skipping the host-pipe cleaning, so the liner bonds to grease, scale, or roots and fails at the wall.
• Missing or failing to mark a lateral before lining, so it seals shut and the building it serves cannot drain.
• Bursting where a parallel utility is too close to the path and gets disturbed by the displaced soil.
• Choosing lining on a collapsed pipe that has no host left and needs bursting or a dig.
• Curing a liner short or cold, off the manufacturer's schedule, so it sets soft and fails early.
• Finishing without a post-installation camera, so there is no proof the wall is tight and the laterals are open.

Field checklist

Standards and references

CIPP installation is covered by ASTM practices for the method, and naming the right one matters because they split by how the liner goes in. ASTM F1216 is the practice for inversion and curing of a resin-impregnated tube, and ASTM F1743 is the practice for the pulled-in-place installation of CIPP. Glass-reinforced and UV-cured systems and sectional point repairs are covered by their own ASTM practices. The structural design of the liner thickness follows the design method in those standards and the associated guidance, and the resin and cure parameters come from the manufacturer for the specific system. Confirm the current edition, because these are revised on a cycle.

Pipe bursting and the replacement pipe carry their own references. The HDPE pipe pulled in is specified to the ASTM polyethylene pipe standards, such as ASTM F714 for outside-diameter-based PE pipe, with AWWA standards like C906 for water and C622 covering pipe bursting practice, and the butt-fusion joining follows the standard fusion procedure. The exact standard that governs a bursting job depends on the pipe, the size, and the owner's spec, so verify the applicable practice and material spec against the project documents rather than assuming a number.

Condition assessment runs on NASSCO's system. The Pipeline Assessment Certification Program, PACP, is the common language for grading what the camera finds and ranking its severity, with companion programs for laterals and manholes, and NASSCO also publishes CIPP installation guidance and inspector training. The plumbing code, the IPC or UPC with local amendments, and the local sewer authority govern the permit, the connection, and the acceptance test. Cite the standard that controls the point, defer the resin, cure, and design-life numbers to the manufacturer, and confirm each reference against the adopted edition and the authority before you put it on a submittal.

Units, terms, and conversions

Trenchless work carries a stack of names for the same methods, and the same job reads differently on a camera report, a spec, and a sales sheet.

Cured-in-place pipe is CIPP, also called pipe lining or relining. Inversion and pull-in-place are the two install methods for it. Pipe bursting, also called pipe replacement or trenchless replacement, pulls in HDPE, high-density polyethylene, fused into a continuous string. Slip lining is the older pipe-in-pipe method with grout. A belly, sag, or back-pitch is the grade defect none of them fix. Pipe size is the nominal diameter in inches, liner and resin properties are the manufacturer's, and the camera findings are graded in NASSCO's PACP language. Diameter loss is the small reduction in inside diameter a liner or a slip pipe leaves behind.

CIPP

Cured-in-place pipe, a resin tube cured inside the host to form a pipe within a pipe

Inversion / pull-in-place

The two ways a CIPP liner is installed, turned inside out or dragged in then inflated

Pipe bursting

Replacing a pipe by pulling a bursting head through it that shatters the old pipe and pulls in new HDPE

HDPE

High-density polyethylene, the fused jointless pipe pulled in during bursting

Slip lining

Pushing or pulling a smaller new pipe inside the host and grouting the annulus

Lateral reinstatement

Reopening a service connection with a robotic cutter after a liner sealed over it

Belly / back-pitch

A sag or reverse grade in the line; a grade defect trenchless does not fix

PACP

NASSCO's Pipeline Assessment Certification Program, the standard language for grading camera findings

Related tools

Calculators and readiness checks for this work

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