Concrete cutting and coring methods and safety field guide

What concrete cutting and coring are, and when you reach for them

Concrete cutting and coring are the controlled removal of hardened concrete with diamond tooling. Cutting uses a saw blade to make straight lines, for an opening, a removal, or a clean edge. Coring uses a hollow diamond bit on a drill to make a round hole, for a pipe, a conduit, an anchor, or a test sample. Both work the same aggregate the same way: diamond against stone, with water or a vacuum carrying the dust and the heat away.

You cut hardened concrete to modify or demolish something that is already built and cured. Cutting a doorway into an existing wall, dropping a floor opening for a new stair or duct shaft, trenching a slab for plumbing, coring for a new sanitary line, taking a core sample for a strength or petrographic test, or cutting a slab into liftable pieces for demolition. The concrete is hard, the embedded steel and utilities are already in it, and you cannot see any of it.

This is a different job from sawing a control joint in a fresh slab. A control joint is a shallow, planned groove cut into green concrete to steer where it cracks, and the timing, depth, and spacing of those cuts are their own discipline. See the control joint layout guide for that work. This guide is about cutting and coring concrete that has already hardened, where the danger is what the blade or bit runs into on its way through.

Why do you scan concrete before cutting?

You scan concrete before cutting because the blade cannot tell rebar from a post-tension cable from a live electrical conduit, and two of those three can kill you. This is the rule that everything else in the job hangs on. Scan first, mark the deck, and cut only where the scan says it is clear. No scan, no cut. That is not caution, it is the line between a routine opening and a hospital trip or a structural collapse.

A reinforced slab can hold mild rebar, welded wire, post-tension tendons, electrical conduit, plumbing, data lines, and embedded steel plates, all in the same few inches. Cut into a tensioned post-tension cable and it releases stored energy with enough force to injure the operator and crack the structure. Cut into a live conduit and you put the saw, the water, and the operator into the same circuit. Hit a water line in a slab and you flood the floor below.

Scanning is the diagnose-first step. Ground-penetrating radar and electromagnetic locators read what is in the concrete before the blade does, so the layout can shift the cut, the core, or the saw line off the steel and the services. On a post-tension deck the scan is not optional under any condition. The rebar placement and cover guide covers how that steel is laid out in the first place, which is the same steel you are now trying to avoid. Treat the scan as a hold point with the same weight a pre-pour inspection gets.

How GPR and electromagnetic locating find what is in the slab

Ground-penetrating radar sends a radio pulse into the concrete and reads the reflections that bounce back off anything with a different density: rebar, cables, conduit, voids, and the back face of the slab. On the screen those reflections show up as hyperbolas, and a trained operator reads their shape and timing to call out what is there and roughly how deep. GPR scans from one side, works on a slab on grade where you cannot get underneath, and it locates non-metallic items like plastic conduit and voids that a metal detector misses.

Electromagnetic locating is the other tool, and it is strong where GPR is weak. It picks up metallic conductors and energized lines well, so the two get used together: GPR to map the rebar and the layout, EM to confirm live conduit and locate energized utilities. Neither one labels a cable for you. The operator interprets the data, and interpretation is where the skill and the liability sit.

Know the limits before you trust the marks. GPR depth and clarity fall off in thick, heavily reinforced, or wet concrete, and a dense top mat of rebar can shadow whatever sits below it. The tools give estimated depth, not a survey-grade number. So mark the clear zones and the exclusion zones on the deck, scan the actual cut path and the full core footprint, not just a spot, and where the data is murky, treat it as occupied, not clear. A scan that cannot see the bottom mat is not a clearance to cut to full depth.

What happens if you cut a post-tension cable?

Cutting a post-tension cable releases the stored tension explosively, and it is the most dangerous mistake in this trade. A post-tension tendon is a high-strength steel strand stretched to thousands of pounds of force and locked into the slab to hold it in compression. Sever it and that energy lets go at once. The strand can whip, the anchorage can blow out, concrete can spall off with force, and the slab loses the compression that was holding it together. People have been killed.

The structural side is just as bad as the safety side. A post-tension slab carries load because the tendons are tensioned. Cut one and you have not just made a hole, you have taken a structural member out of a system that was designed around it. The repair runs into tens of thousands of dollars, often far more, and it can mean shoring the floor, re-stressing or splicing the tendon, and an engineer's redesign before anyone walks on it again.

The rule on a post-tension deck is absolute. Scan every cut and every core, every time, with no exception for a small hole or a shallow cut. If the building might be post-tensioned and you cannot confirm it is not, treat it as PT and get the structural engineer involved before any blade or bit touches it. You do not cut, core, or even drill an anchor into a PT slab on a guess. The cost of scanning is nothing against the cost of being wrong once.

The flat saw, or slab saw

A flat saw, also called a slab saw, is a walk-behind machine with a diamond blade that cuts horizontal surfaces: floors, slabs, roadway, and bridge decks. One operator walks it along a marked line, the blade spins down into the concrete, and water feeds the cut to cool the blade and hold the dust. It is the workhorse for floor openings, trench lines for plumbing, pavement removal, and cutting a slab into sections for demolition.

Depth of cut comes from the blade diameter, since a circular blade can only reach a little less than its radius below the surface. A typical walk-behind blade cuts somewhere in the range of several inches up to roughly a foot, and going deeper means a larger machine and a larger blade. The cut is straight and clean on the top, but the blade leaves a small uncut wedge where it cannot reach into a corner, which is the overcut problem covered later.

The flat saw is the method most associated with respirable silica, because it generates a lot of dust over a long run. Run it wet, or run a dry version only with the manufacturer's integrated water or vacuum dust collection in place. A dry flat saw cutting with no dust control in an occupied space is exactly the exposure the silica rule was written to stop.

The wall saw, or track saw

A wall saw, or track saw, is a circular diamond blade mounted on a track bolted to the surface, so the cut is guided and precise instead of freehand. The track lets it cut vertical walls, steep faces, and overhead, where a walk-behind flat saw cannot go. It is the tool for precise openings: a door or window cut into an existing wall, a clean rectangular opening for an elevator or duct, and deep, accurate cuts where the line has to be straight and the face has to be square.

Wall saws cut deep for their size because the head can be flipped and the blade plunged from both faces, and on a thick wall they often cut from both sides to meet in the middle. The track holds the line tighter than a hand can, so the opening drops out clean with square corners and a flat cut face. Power is usually hydraulic or high-frequency electric, which keeps the cutting head compact and strong.

Because a wall saw makes structural openings in existing walls, it is the method that most often needs an engineer ahead of the cut. An opening in a bearing or shear wall changes how the wall carries load, and the size, location, and any new lintel or frame are the engineer's call, not the cutter's. Scan the wall, mark the clear path, and have the structural detail in hand before the track goes up.

The wire saw

A wire saw cuts with a continuous loop of diamond-beaded wire pulled through the concrete under tension by a hydraulic drive. The wire wraps the section and the machine reels it through, so the cut is limited by the length of wire, not the diameter of a blade. That makes it the method for mass concrete, very thick sections, heavily reinforced members, and odd shapes where a circular blade simply cannot reach deep enough.

Wire sawing earns its keep on the big and the awkward: cutting a bridge pier, a thick foundation, a heavy column, or separating a large mass for removal in pieces. It cuts through dense reinforcement and concrete together, it can turn cuts around corners that a blade cannot make, and it works underwater and in tight quarters where a saw frame will not fit. It is slower to set up because the wire has to be threaded and the drive anchored, so it is reserved for the cuts the other saws cannot do.

The wire is under heavy tension, and a wire that breaks under load can lash out, so the cutting zone gets kept clear and barricaded. This is specialized work, usually a dedicated crew with the rig and the experience to run it. The hazard is the stored energy in a tensioned wire, the same family of danger as a post-tension cable, just on the tool side instead of in the slab.

The hand saw, or cut-off saw

A hand saw, or cut-off saw, is the handheld machine with a diamond blade for small cuts, touch-ups, and the corners and edges the big saws cannot reach. It is fast to grab and fast to start a fire if you treat it casually. Most field cuts that are short, shallow, or in an awkward spot get made with a handheld, which is exactly why it accounts for a large share of the injuries.

Kickback is the hazard that hurts people. Pinch the blade in the cut, hit unexpected steel, or use the wrong part of the blade and the saw can drive back toward the operator faster than you can react. You cut with the lower front quarter of the blade, you keep both hands on the saw, you let the blade reach full speed before it touches concrete, and you never bind it in a deep cut where the kerf can close on it. A handheld with an abrasive or cracked blade is a thrown-fragment risk on top of the kickback.

Dust is the other problem, because a handheld is small enough that crews run it dry without thinking. Cutting concrete dry with a handheld and no water or vacuum is one of the highest silica exposures on a jobsite. Run the integrated water feed, or run a vacuum shroud rated for the saw, and wear the respirator the silica rule calls for. Small saw, full-size hazard.

What is core drilling?

Core drilling is cutting a round hole through concrete with a hollow diamond bit on a rotating drill, leaving a cylindrical plug, the core, that gets pulled out when the hole is through. The bit is a steel tube with diamond segments brazed to the cutting end, so it grinds a ring while the center stays solid and lifts out as a slug. The result is a clean, round, accurate hole with no cracking around it, which is why coring is the method for penetrations.

You core for the things that need a precise round opening: plumbing risers, conduit and cable sleeves, anchor and dowel holes, HVAC and refrigerant lines, and core samples cut for compressive strength or petrographic testing under the standard test methods. Hole sizes run from an inch up to a couple of feet, and deeper or larger holes call for a rig anchored or vacuum-mounted to the surface to hold the bit dead straight.

The rig matters as much as the bit. A handheld core drill works for small, shallow holes, but anything precise or large goes on a stand bolted, vacuum-anchored, or jacked to the surface, because a core bit that wanders or wobbles binds and stalls. Water feeds through the bit to cool the diamonds and flush the cuttings out as slurry. And the same rule applies as for any cut: scan the full footprint of the core, not just the center point, before the bit goes down, because a core can clip a tendon or a conduit just as easily as a saw cut can.

Matching the diamond blade and bit to the job

Diamond does the cutting, but the bond around the diamond and the blade design decide whether it cuts fast, lasts, and stays safe. A blade or bit that does not match the concrete dulls, glazes, overheats, or wears out early, and the wrong blade on a handheld is a thrown-fragment risk. The match is to the aggregate hardness, the reinforcement, and whether you are running wet or dry.

Segmented blades have gaps between the diamond segments that let water, slurry, and air move through, which keeps the rim cool and clears the cut. That makes them the general choice for concrete, asphalt, and reinforced work. Continuous-rim blades have no gaps and leave a smoother edge with less chipping, so they suit tile, stone, and finish cuts, but they need water and they cut slower in heavy material. For most structural concrete cutting and coring, the segmented design is what you reach for.

Read the blade before you trust it. A glazed blade with the diamonds buried and polished has stopped cutting and is just heating, and you dress it on an abrasive block to expose fresh diamond. A blade losing segments, cracked in the core, or worn past its segment height comes off the saw. The bond is matched to the material on purpose: a softer bond wears away faster to keep exposing diamond in hard aggregate, a harder bond holds longer in soft or abrasive material. Match it wrong and the blade either glazes or wears out in an afternoon.

Should you cut concrete wet or dry?

Cut wet whenever the tool and the job allow it. Water does two things at once: it cools the diamond rim so the blade lasts and cuts true, and it knocks the respirable silica dust out of the air at the source, which is the single most effective control for the health hazard. Wet cutting is the default for a reason, and on most concrete it cuts faster and cleaner because the slurry carries the cuttings out of the kerf.

Dry cutting has a place, mainly where water cannot be used: an electrical hazard nearby, a finished interior where slurry would ruin the floor, or short cuts where a wet setup is not practical. Dry cutting is only acceptable with a dust extraction system, a shroud and a vacuum rated for fine dust, integrated with the saw and actually running. A dry blade also needs to dissipate heat through its design and cannot be pushed as hard, because there is no water carrying the heat away, and an overheated dry blade can lose segments.

The trade-off is dust versus slurry, and you manage whichever one you create. Wet cutting controls the dust but produces slurry you have to contain. Dry cutting avoids the slurry but produces dust you have to capture with a vacuum and a respirator. There is no version where you cut concrete and create nothing. The wrong answer, the one the silica rule exists to stop, is dry cutting with neither water nor vacuum, sending raw concrete dust into the air everyone is breathing.

Is concrete dust dangerous?

Yes. Concrete dust contains respirable crystalline silica, and breathing it over time causes silicosis, an incurable scarring of the lungs, along with raised risk of lung cancer, COPD, and kidney disease. Cutting, coring, grinding, and drilling concrete all generate fine silica dust small enough to reach deep into the lungs, and the damage is cumulative and permanent. This is the slow hazard, the one that does not put you in the hospital the same afternoon and so gets ignored until the lungs are already scarred.

OSHA regulates it under the respirable crystalline silica standard for construction, 29 CFR 1926.1153. The standard sets a permissible exposure limit of 50 micrograms per cubic meter as an 8-hour time-weighted average, with an action level of 25 micrograms that triggers monitoring and medical surveillance. Verify the current numbers and requirements against the rule itself and the adopted version, because enforcement details and interpretations change.

The practical path most cutting crews use is Table 1 in that standard. Table 1 lists common tasks, including handheld saws, walk-behind saws, and core drilling, and pairs each with a specified control, either a water-fed dust suppression system or a vacuum dust collection system, plus the respiratory protection the table calls for. Implement the Table 1 control fully and properly for your task and OSHA treats you as compliant with the exposure limit without having to run air sampling. So the firm message is simple: cut wet or cut with vacuum extraction, wear the respirator the table specifies, and never run a saw dry and bare. Confirm your specific task's row and required respirator against 1926.1153 Table 1, because the control and the respirator depend on the tool and the duration.

Containing and disposing of the slurry

Wet cutting solves the dust problem by creating a slurry problem. The water mixed with cut concrete comes out as a gray, gritty, highly alkaline slurry, and it is not clean water you can hose into a drain. Concrete slurry carries fine solids and a high pH that can clog storm drains, foul the sanitary system, and harm aquatic life if it reaches a stream or a storm sewer. Letting slurry run to a drain is both an environmental violation and a way to plug a pipe solid when it sets.

Contain it at the source while it is still wet. Dam the cut area, vacuum the slurry up with a wet vac as you go, or work over a lined containment so the slurry collects instead of spreading. Squeegees, berms, and a slurry vacuum are the everyday tools. The mistake is walking away and letting it harden across the floor or run downhill, because cured slurry is far harder to remove than wet slurry and a hardened drain is a real bill.

Disposal follows local rules, and they vary, so confirm them for the jurisdiction. Common practice is to collect the slurry, let the solids settle or dewater them, dispose of the solids as solid waste, and handle the high-pH water per the local requirements rather than dumping it. On road and site work some agencies have specific concrete slurry guidance. Do not assume a parking lot drain is a legal outlet. Plan where the slurry goes before the saw starts, the same way you plan where the cut goes.

Cutting changes the structure

Every cut and every core removes material the structure was counting on, and on a structural member that is an engineering decision, not a field call. An opening in a slab, a bearing wall, a beam, or a column changes how that element carries load, and cutting the reinforcement that runs through it removes capacity that has to be replaced or worked around. The cut can look fine on the day and leave the member weaker than the design ever allowed.

The hard rule: do not cut structural reinforcement or post-tension, and do not make a structural opening, without the structural engineer of record. The engineer decides whether the opening is acceptable, where it can go, how big it can be, what reinforcement can be cut, and what new framing, lintel, or shoring the opening needs. A doorway in a partition wall is one thing. The same size hole in a shear wall or a one-way slab is a different problem entirely, and the cutter is not the one who gets to decide which it is.

This is also why the scan and the engineering go together. The scan tells you where the steel and the tendons are, and the engineer tells you what you are allowed to cut through and what you must avoid. Cut first and ask later and you may have already removed capacity that cannot be added back without shoring the floor and rebuilding the member. Get the detail in hand before the blade goes in.

Laying out the opening and dealing with overcut

A clean opening starts with accurate layout and an honest accounting of overcut. Snap the lines, confirm them against the scan marks so the cut clears the steel and the services, and mark which side of the line is the keeper and which is the waste. On a wall saw the track sets the line. On a flat saw the operator follows the snap line, so a crooked line is a crooked opening.

Overcut is the wedge a circular blade leaves at every inside corner. Because the blade is round, when the cut reaches full depth at the surface line, the bottom of the cut stops short at the corner, and the corner is not fully severed until you either overrun the line on top or finish the corner another way. On a structural slab where the cut face shows or the overcut would clip something it should not, you stop the saw short of the corner and finish the corner with a handheld saw, a chain saw made for concrete, or a core at the corner to relieve it.

Decide the corner method before you cut, because it changes the layout. If overcutting past the line is acceptable, the opening drops fast. If it is not, you plan the corner finishing into the sequence so the piece still releases cleanly. The rookie version is sawing to the line on top, finding the corners still attached at the bottom, and then prying or sledging the piece, which cracks the slab past the opening you wanted.

Why is my core bit or blade stuck?

A bound core bit or pinched blade almost always means the cut closed on the tool or the tool wandered into steel. On a saw, the kerf pinches the blade when the concrete moves: a slab settles as you cut through it, a piece starts to drop, or the cut runs without a relief and the weight of the section squeezes the blade. The blade stops, the saw lurches, and on a handheld that lurch is kickback.

On a core bit, binding usually comes from one of a few things. The rig is not anchored solid, so the bit wobbles and jams in its own kerf. The slurry is not flushing, so the cuttings pack around the bit and seize it. The bit hits heavy rebar at a bad angle and grabs. Or the hole goes off plumb because the rig moved, and the bit binds against the side of the hole it no longer matches.

The fixes follow the causes. Support the work so the cut cannot pinch: cut in a sequence that keeps the kerf open, and on a large slab section, plan how the piece is held or rigged before the last cut frees it. Anchor the core rig solid and keep it plumb. Keep water flowing so the cuttings flush out instead of packing. If a bit does bind, stop, back off the feed, and free it deliberately rather than forcing it, because forcing a bound bit twists the drive and can throw the operator. Forcing a stuck tool is how the small problem becomes the injury.

Live utilities in the slab: electrical, gas, and water

Embedded utilities turn a cut into a hazard with no warning, and electrical is the one that kills fast. A live conduit cast in a slab puts an energized line right where the blade is going, and a diamond saw running water is a conductor and the operator is in the loop. Cut into an energized conduit and the fault can electrocute the operator, arc, and explode the conduit. Locate the electrical, confirm it, and de-energize and verify it dead before you cut where it runs.

Gas and water and sanitary lines are the other embedded services. A gas line in or under a slab is an explosion and asphyxiation risk if the saw opens it. A water or sanitary line floods the space and the floor below. Communications and data conduit is a costly outage if you cut it, even if it will not hurt you. The locate has to find the non-electrical services too, which is where the GPR and the as-builts come in alongside the EM locator.

The sequence is locate, de-energize, verify, then cut. Get the as-builts, scan the path, identify every service crossing the cut, and for anything energized, lock it out and prove it dead with a meter on a known source, not on the word of a drawing. The drawing is a starting point, not a clearance. Slabs get modified over the years and the conduit that is actually there is rarely exactly where the original print put it.

Firestopping a cored or cut rated assembly

When you core or cut through a fire-rated floor or wall, the penetration has to be firestopped to restore the rating the assembly had before you opened it. A rated slab or wall is built to hold fire and smoke for a set time, and a raw hole through it is a path for both. Running a pipe or conduit through and leaving the annular space open defeats the rating at that spot, and the inspection catches it, or the fire finds it.

Firestop is a tested system, not a tube of caulk chosen by feel. The penetrating item, the barrier, and the firestop material together have to match a tested UL system, and that system specifies the materials, the depth, and the minimum and maximum annular space that achieves the listed rating. Too tight or too loose an annular space and the tested system no longer applies. The penetration schedule on a real job ties each penetration to the specific UL system that covers it.

Coordinate this before you core, not after. Knowing the firestop system tells you the hole size the annular space needs, so the core is sized to the system instead of forcing a system to fit a hole someone already cut. The cutter opens the rated assembly, and someone owns closing it back to its rating. Make sure that handoff is in the plan, because an unsealed penetration in a rated barrier is a life-safety defect, not a punch-list cosmetic.

Rigging out the cut, and access, noise, and vibration

The cut is half the job. Getting the cut piece out safely is the other half, and a slab section weighs far more than it looks. Concrete runs around 150 pounds per cubic foot, so a modest floor opening can free a piece that weighs several hundred to a few thousand pounds. Before the last cut releases it, you decide how the piece is held, lifted, and lowered, because a freed section that drops is a crush hazard to the crew and to whatever is below.

Plan the rigging into the cut sequence. Set lifting anchors or a strap before the piece is fully cut, support it from below or hold it from above so it cannot drop when the last cut breaks through, and control the lower of a floor cut onto the level beneath. On a wall opening, the piece can tip out toward the crew. Barricade the area below a floor cut, because the hazard is the piece and anything else that falls through the new hole.

Access, noise, and vibration shape the method too. A wall or wire saw reaches what a walk-behind cannot, but it needs anchor points and clearance. Diamond cutting is loud enough to need hearing protection and, in occupied buildings, off-hours work. The vibration and the cut can disturb sensitive equipment nearby. And when the cut is done, clean up: collect the slurry, vacuum the dust, decontaminate the area, and do not track silica-laden residue through the building. The cut is not finished until the mess it made is contained.

Cutting in a live or critical facility

Cutting in an operating facility, a data center, a hospital, a clean space, or a tenant floor that never shuts down, raises the stakes on every control. The dust, the slurry, the vibration, and the noise all have to be managed around systems and people that cannot tolerate them. A little airborne silica dust is a health issue anywhere. In a data center it is also a contamination event for the equipment, and the vibration from a saw can trip sensitive hardware.

The work goes tighter and slower on purpose. Scan around the live systems and the cable trays and the conduit feeding them, isolate the cut area with containment and negative air so dust does not migrate into the space, capture all slurry, and keep water away from energized equipment. Coordinate with the facility so the affected systems are protected or scheduled around, and confirm what vibration the nearby equipment can take. In a critical space the answer to too much risk is sometimes a different method, a wire saw or coring that runs cooler and quieter than a flat saw pounding through a deck.

The principle that does not change is scan-first and engineer-for-structural, just with more parties at the table. The facility owner, the structural engineer, and the trades whose systems run through the slab all have a say before the cut. A cut that would be routine on an empty shell becomes a planned operation in a live building, and the planning is what keeps a modification from becoming an outage.

What to document

A core or saw cut leaves no trace of the scan that cleared it or the engineer who approved it, so the written record is what stands behind the cut when its safety is questioned later. The record matters most for the things that go invisible the moment the work is done: what the scan found, who cleared the cut, and what authority signed off on a structural opening. When a question comes up about whether a cut was safe or approved, the record is the answer, and on a structural or post-tension job it is the difference between a documented decision and an exposed one.

Capture the scan results and who interpreted them, the method and tool used, the location and size of every cut and core, the structural approval for any structural opening, the silica control in place, where the slurry went, and the firestop system for any rated penetration. Tie each to a date and a name. The point is that the next person, the inspector, the engineer, or the owner, can see what was located, what was cut, who approved it, and how the hazards were controlled.

Common mistakes

• Cutting or coring without scanning the full cut path and core footprint first.
• Hitting a post-tension cable because the slab was not confirmed and scanned as PT.
• Dry cutting with no water and no vacuum, sending respirable silica into the air.
• Rinsing concrete slurry into a storm drain or sanitary line instead of containing it.
• Cutting structural reinforcement or making a structural opening without the engineer.
• Running the wrong blade or bond for the aggregate, so it glazes, overheats, or wears out.
• Leaving a rated penetration unsealed with no firestop after coring through it.
• Freeing a cut slab section with no rigging plan, so the piece drops.
• Forcing a bound core bit or pinched blade instead of stopping and freeing it.

Field checklist

Standards and references

The silica hazard is governed by OSHA's respirable crystalline silica standard for construction, 29 CFR 1926.1153, which sets the permissible exposure limit and the Table 1 task-and-control framework that most cutting crews work to. Confirm the exposure numbers, the task rows, and the required respirators against the rule and the adopted version, because the details and interpretations change. The general industry counterpart is 1910.1053, but construction cutting falls under 1926.1153.

Method, equipment, and safe-practice guidance for sawing and drilling comes from the Concrete Sawing and Drilling Association (CSDA), whose training and best-practice material covers slab, wall, and wire sawing and core drilling. For core samples cut for testing, the standard test methods govern how the core is taken and tested. Locating embedded items relies on ground-penetrating radar and electromagnetic locating, and on a possible post-tension slab the scan is non-negotiable.

The two calls that are not the cutter's to make: anything structural goes to the structural engineer of record, who controls openings, what reinforcement can be cut, and what new framing or shoring is needed; and any rated penetration gets restored with a tested firestop system, commonly a UL-listed through-penetration system matched to the penetrant and the barrier. Cite the standard that controls the point, let the project specification and the adopted code edition govern, and when the data or the structure is in doubt, scan again and get the engineer. The two messages that do not bend are scan before you cut and engineer for anything structural.

Units, terms, and equipment

Concrete cutting uses a mix of terms across the saws, the scans, and the safety rule, and the same idea goes by different names on different sheets.

Cut depth and blade size are given in inches or millimeters, water flow in liters or gallons per minute, and the silica exposure limit in micrograms per cubic meter as an 8-hour time-weighted average. Slab sawing is also called flat sawing, a wall saw is also called a track saw, and the plug a core bit leaves is the core or the slug. Post-tension is often shortened to PT, ground-penetrating radar to GPR, and respirable crystalline silica is the dust the OSHA rule regulates.

GPR

Ground-penetrating radar, used to locate rebar, cables, conduit, and voids before cutting

Post-tension (PT)

Tensioned steel tendons in a slab; cutting one releases stored energy explosively

Flat saw / slab saw

Walk-behind diamond saw for horizontal surfaces like floors and pavement

Wall saw / track saw

Track-mounted diamond blade for vertical and precise deep cuts

Wire saw

Diamond-beaded wire for thick, massive, or odd-shaped cuts a blade cannot reach

Core / slug

The cylindrical concrete plug left inside a hollow core bit when the hole is through

Respirable crystalline silica

Fine concrete dust that causes silicosis; regulated under OSHA 1926.1153

Slurry

The alkaline water-and-concrete mix from wet cutting that must be contained, not drained

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