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Dust-collection ducting is easy to damage in a busy shop. A forklift mast, pallet corner, sheet of plywood, or rolling tool chest can crush a pipe in seconds. The resulting leak reduces suction, spreads fine dust, and may leave sharp plastic or metal edges in a traffic lane. Protection should be designed around the way materials actually move through the shop, not added after the first accident.
Start With the Traffic Pattern
Mark forklift lanes, pallet drop zones, door swings, and the largest items you routinely move. Include the space needed to turn, not just the straight-line path. A duct that is 12 inches outside the normal lane may still be vulnerable when a loaded pallet is turned or a fork is raised.
Keep ducts out of forklift travel lanes whenever possible. Routing them overhead is usually safer than building a guard around a low pipe, but overhead routing has its own hazards. Maintain at least 12 feet of clearance where forklifts operate unless your equipment and local rules require more. Check the actual maximum lift height, mast tilt, and load height; a “high” duct can still be struck by an elevated pallet.
For pedestrian areas, protect low ducting from carts and stock. A simple rule is to treat anything below about 7 feet as reachable or impact-prone in a working shop. Do not rely on bright paint alone. Visibility helps, but it does not stop a moving load.
Choose the Right Duct Material
Thin flexible hose is the most vulnerable option. It collapses, tears, and catches on corners, although it is useful for short tool connections. Use rigid pipe for the main runs and limit flex hose to roughly 3 to 6 feet at a machine when practical.
For a vulnerable exposed section, spiral steel duct is generally a better choice than thin PVC. Steel resists abrasion and impact, and its round shape is less likely to be crushed by a glancing blow. PVC can be acceptable in a protected overhead run because it is light, smooth, and easy to install, but it becomes brittle in cold conditions and can split from a sharp impact.
| Option | Best use | Strength | Main drawback |
|---|---|---|---|
| Flexible hose | Short machine connections | Easy to route and inexpensive | Crushes and tears easily; higher airflow loss |
| Rigid PVC | Protected overhead runs | Smooth interior and simple installation | Can crack or shatter when struck |
| Spiral steel duct | Exposed or impact-prone runs | Good durability and repairability | Costs more and requires careful grounding |
| Steel pipe with bollards | Low wall or corner runs | Best physical protection | Uses floor space and needs a substantial barrier |
If you are buying new pipe for an exposed section, compare spiral steel dust-collection duct with PVC based on replacement cost, not just purchase price. The cheaper pipe is fine when it is genuinely out of reach and protected from stored materials.
Build a Real Barrier
The most reliable floor-level protection is a pair of steel bollards or a stout guard frame installed between traffic and the duct. Use schedule 40 steel pipe, heavy angle iron, or structural tube rather than light electrical conduit. A barrier that bends on the first impact can transfer the load directly into the duct.
Place posts far enough from the duct to leave room for inspection and repair. A gap of 6 to 12 inches between the barrier and pipe is a useful starting point, but size it around the loads in your shop. Keep forklift forks from sliding underneath the guard. A low horizontal rail, curb, or plate can help, provided it does not create a trip hazard.
Anchor guards into concrete with properly rated mechanical or chemical anchors. Do not fasten a protective post only to a thin slab, wood floor, or the duct support itself. The guard needs to absorb a bump without pulling down the duct or cracking a wall. If forklifts regularly pass within a few feet, use commercially rated bollards or have a qualified fabricator size the protection.
For corners and wall runs, a steel rack or framed plywood shield can work when impacts are light. Plywood is a sacrificial cover, not a forklift barrier. Use it to stop carts, lumber ends, and casual contact—not a loaded pallet.
Support and Isolate the Duct
Impact protection will not help if the duct is poorly supported. Install hangers at the spacing specified by the duct manufacturer; as a practical check, many small shop runs need supports about every 6 to 10 feet, with extra support near elbows, blast gates, and machine drops. Never let a flexible hose hang from a machine port or blast gate.
Use padded or wide straps that do not crush the pipe. Leave enough room to inspect seams and fasteners. Where a duct passes near a wall, rack, or guard, prevent rubbing during vibration. A damaged spot can become a tear months before anyone notices a loss of suction.
Make blast gates and cleanouts accessible, but keep their handles out of the impact zone. A broken gate can leak enough air to affect several machines. Install a flexible connector near vibrating equipment so movement is not transmitted into a rigid run.
Protect High-Risk Points
Elbows, wyes, reducers, and machine drops deserve extra attention. They project into the aisle and are harder to replace than a straight section. Use steel dust-collection elbows at exposed turns, and put the straight, replaceable section where a minor impact is most likely.
At loading doors, consider a removable guard so deliveries can enter without dismantling the duct. Mark the guard and nearby clearance with high-visibility yellow and black striping. Add signs showing the maximum safe clearance, but do not treat signage as the primary control.
Inspect After Every Impact
After any contact, shut down the collector and inspect the pipe, hangers, seams, blast gates, and machine connections. Look for oval-shaped pipe, pulled screws, cracked PVC, loose supports, and dust trails around joints. A small leak can be found by listening for a hiss or using smoke from an incense stick while the collector runs; keep smoke and flame away from combustible dust and follow your shop’s fire-safety rules.
Keep a short replacement section and compatible clamps on hand. For flexible hose, dust-collection hose and clamps are inexpensive repairs, but do not patch a crushed main duct with tape. Replace damaged pipe, then check airflow at the affected machine.
A Practical Buying Plan
Spend first on rerouting the duct out of traffic. Next, use rigid steel at unavoidable exposure points and install anchored barriers at corners, doors, and pallet areas. Use PVC and lighter guards where the duct is permanently overhead and inaccessible. This combination normally costs less than using heavy steel everywhere while providing protection where an impact is actually likely.