Planning a diamond core-drilling job

Scope. This is a fail-closed planning sequence for a bounded drilling route. It does not assess a structure, locate services, design rig anchorage or select a product.

Define the hole before choosing equipment

Record finished diameter and depth, material, orientation, access on both faces, dimensional tolerance and the purpose of the opening. State whether the core must pass through, stop blind or meet another opening. Identify what happens when the core breaks free and how its weight will be controlled.

Measure depth through the actual build-up, not from an assumed wall label. Allow for render, screed, finishes, cavities and changes of material, but do not convert uncertainty into extra millimetres. If the far face cannot be inspected, record the uncertainty and establish a control before drilling.

Access includes room for the machine/stand, feed travel, extraction or water equipment, lifting/handling and the operator’s position. An opening that fits the bit on paper can still be outside the system’s working envelope.

Mark a coordinate reference that the structural/services reviewer and drilling team can both identify. A diameter and depth without a controlled centre point can produce the right hole in the wrong place. Include allowable positional tolerance and who releases the mark.

Identify material and reinforcement

Distinguish concrete, reinforced concrete, masonry, engineering brick, stone and mixed build-ups. Unknown reinforcement is not the same as “none”. Obtain drawings where reliable, scan using an appropriate method, interpret results competently and define what happens when results are inconclusive.

Do not drill through reinforcement merely because the bit can cut it. Reinforcement may be structurally significant, and an opening itself can affect stability. HSE’s structural-stability guidance stresses planning and competent engineering input for work that can affect a structure. [HSE]

Also identify the material’s age and any coating, insulation or concealed layer relevant to hazardous substances. Suspected asbestos invokes a separate stop before disturbance. [HSE]

Scanning has limits set by technology, access, calibration and interpretation. Record the scanner, operator, survey grid, depth limits and ambiguous areas. Where the far face or one scanning direction is inaccessible, the limitation belongs beside the services/reinforcement conclusion.

Choose a provisional wet, dry or rig route

Choose wet or dry only where the core system, bit and material manufacturer support that method. Wet drilling can aid cooling and dust suppression, but adds water delivery, slurry, electrical and containment questions. Dry drilling needs effective source extraction and is not a universal alternative.

Handheld and stand-mounted routes are not divided by one legal diameter. Hilti describes a manufacturer-specific diamond-coring range including handheld applications up to 162 mm, while its DD 350-CA heavy rig is stated for diameters up to 500 mm. These are cited range examples, not statutory thresholds or universal capacity limits. [MFR] [MFR]

The Job Lab table can therefore return a provisional handheld, light-stand or heavy-stand route only after hazard suppression. The actual system must be checked for material, diameter, depth, orientation, power, anchorage, method and bit. [POLICY]

A stand route brings setup forces and handling. Check the stand, base, column, carriage, fastening/vacuum indication and permitted orientation as one manufacturer system. A heavy rig’s diameter range says nothing about whether its base can be established at the proposed location.

Depth needs a component check

Required depth must fit the complete system: core barrel working length, usable segment/barrel geometry, extensions, stand column and carriage travel, spindle/adaptor stack and room to withdraw the core. Overall barrel length is not necessarily working depth.

Where depth exceeds one barrel pass, document the manufacturer’s extension and re-coring procedure. Removing a core, extending and restarting changes handling, alignment, water/extraction and jam risks. Never infer capacity from diameter/depth fields alone.

Deep coring also creates a long, heavy core. Estimate its mass from verified geometry/material only if that helps handling planning, but do not rely on a generic density to design retention. Break the handling into removal stages approved by the method and prevent an unsupported core from falling.

Structural, services, anchorage and breakthrough controls

Locate electrical, gas, water, communications and other concealed services using drawings, detection and site information appropriate to the job. A scanner reading is evidence to interpret, not a guarantee of an empty path. Unknown or conflicting service information stops equipment routing.

Obtain structural confirmation where the opening, reinforcement, post-tensioning, edge distance or sequence could affect the structure. For stand drilling, design the anchorage/vacuum arrangement for the actual substrate, orientation and machine instructions. Do not improvise anchors or rely on body weight.

Plan the far side: exclusion, catching/retaining the core, protection from water/slurry and the condition of the emerging opening. Overhead work adds falling core, water and electrical controls. HSE’s construction HAV guidance also reinforces planning lower-vibration methods and exposure management rather than focusing only on trigger time after the fact. [HSE]

Agree a permit/release point after drawings, scanning and structural review. The person drilling needs an unambiguous stop if the material changes, reinforcement is encountered contrary to the plan, water is lost, the stand moves or the breakthrough side cannot remain controlled.

Dust, water and slurry control

For dry drilling, capture dust at source with the task-appropriate shroud/collar, hose and extractor, then clean with controlled extraction. For wet drilling, deliver water as the system requires and contain slurry at both faces. Slurry is not “dust solved”; it needs collection, handling and disposal without spreading contamination.

Wet overhead drilling requires a manufacturer-supported water collection method and a site-specific electrical arrangement. Protect people and property below, and do not let water reach unsuitable electrical equipment. Read Controlling dust at the source and, where 110 V equipment/leads are involved, Planning 110 V power.

Collect slurry close to the source before it runs into cavities, drains or occupied areas. Define containers, wet-vacuum compatibility, transport and disposal for the identified material. Dried slurry can become airborne dust during later clean-up.

Power and water must be planned as interacting systems. Identify supply voltage, protective arrangement, connectors and cable route, then keep water collection away from unsuitable electrical parts. A 110 V label alone does not resolve the arrangement. The drilling system’s manufacturer instructions govern water delivery, while a competent electrical person confirms the site distribution where required.

Also plan pauses. A stopped bit can remain bound in the core, and a partially cut core can be unstable. Define isolation, pressure release, stand security and restart/abandonment steps for loss of power, water or extraction. If the stand shifts or the cut departs from the intended line, stop and reassess alignment and anchorage rather than correcting under load.

Worked 180 × 350 mm reinforced-concrete case

The requested opening is 180 mm diameter × 350 mm deep through reinforced concrete. The simple table places 180 mm above the cited 162 mm manufacturer handheld range, so the provisional route is a heavy stand-mounted system. That label is a prompt, not a product choice. [MFR]

Before the route can remain visible, the record needs: verified material and reinforcement/structural approval; services clearance; wet/dry method supported by the system; a core barrel/extension and stand travel component check for 350 mm; anchorage design; power and water arrangement; capture/slurry plan; access and manual handling; and controlled breakthrough.

If any one is unknown, record the missing confirmation and suppress the affected route. Do not name a hire product, infer a particular rig from the 500 mm example or treat diameter capacity as proof of depth.

See the core-drill source group and Methodology for table boundaries and change control.

This route cannot confirm structural effects, concealed services, anchorage, operator competence or a complete drilling system. Those confirmations govern the job.