Commercial Ductwork: Large Diameter Penetrations
Application Overview
Commercial HVAC ductwork installation requires large-diameter penetrations through masonry walls and reinforced concrete slabs. Rectangular and round ducts pass through fire-rated walls and floor slabs, each penetration demanding clean edges for compliant firestop sealing. Zhonghuan supplies TCT wall hole cutters for masonry penetrations up to 150 mm, diamond core drills for RC slabs up to 200 mm, and SDS-Plus bits for the hanger and trapeze anchoring that supports the duct run.
Recommended Products
| Product | Size Range | Commercial Ductwork Use |
|---|---|---|
| Wall Hole Cutter (TCT) | 100-150 mm | Rectangular/round duct through brick, block, masonry walls |
| Diamond Core Drills | 100-200 mm | Duct penetrations through reinforced concrete slabs and beams |
| SDS-Plus Masonry Bits | 8-16 mm x 160-450 mm | Hanger bolts, trapeze brackets, and duct support anchoring |
Application Scenarios
1. Round Duct Through Masonry Partition Wall
Material: Brick or concrete block wall, 200-300 mm thick
Recommended: TCT wall hole cutter, 100-150 mm
Notes: Size the cutter to duct OD + 15 mm minimum for sleeve and firestop clearance. Score both faces of the wall before full penetration to prevent blow-out on the exit side. For fire-rated walls, install an intumescent fire collar or damper to the rated specification immediately after drilling.
2. Duct Riser Through RC Floor Slab
Material: Reinforced concrete, 200-350 mm thick
Recommended: Diamond core drill, 150-200 mm, wet cutting
Notes: Rig-mounted drilling with continuous water feed for segment cooling and dust suppression. Scan for rebar and post-tension cables before every penetration. Use a vacuum base plate or expansion anchor to secure the rig to the slab. Collect slurry with a water ring and wet vacuum. After coring, the hole provides a clean, dimensionally accurate seat for the fire damper or sleeve.
3. Duct Support Hanger Anchoring
Material: Concrete soffit (ceiling slab)
Recommended: SDS-Plus 2-cutter, 10-12 mm x 160-210 mm
Notes: Commercial duct runs require hanger rods or trapeze brackets every 1.5-3.0 m depending on duct size and weight. Drill depth must match the expansion anchor specification exactly. Clear all dust from each hole before inserting the anchor. For heavy rectangular duct, use M10 or M12 anchors with verified pull-out load ratings.
Selection Tips
- Masonry = TCT wall hole cutter; RC slab = diamond core: never use TCT on rebar-reinforced concrete.
- Penetration diameter = duct OD + 15-30 mm to accommodate sleeves, insulation, and firestop collars.
- Fire compliance drives tool choice: clean edges from TCT or diamond allow fire collars to seat properly. Rough percussion holes do not pass inspection.
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