What's inside
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Dust ducts often run through the part of a shop where long boards, sheet goods, carts and tool handles move. A dent can reduce airflow; a split or knocked-loose fitting can spread dust into the shop. Protecting the ductwork starts with choosing a route that avoids impacts, then guarding the few places that cannot be moved.
Inspect the route before adding guards
Walk the path a workpiece takes from storage to each machine. Include awkward moves such as turning a full sheet of plywood, carrying a ladder or rolling a tool cabinet. Mark likely contact points on the duct: low overhead runs, corners beside a bench, and drops near machine infeed and outfeed areas.
Look for existing damage while you are there. Thin-wall metal duct can dent without showing a leak, while plastic pipe may crack at a fitting or become loose where it is supported. Check joints, blast gates and flexible hose for gaps. A guard will not fix a leak or a badly supported run; repair those first.
Start with placement, not armor
The least expensive protection is often to move the duct. Run it high enough to clear the tallest material you routinely handle, and keep vertical drops close to the machine they serve rather than across a walkway. When a duct must cross a traffic lane, raise it or route it along a wall where possible. Leave room to remove filters, open gates and service machines.
A longer route can add resistance, especially if it includes tight elbows, narrow sections or corrugated flex hose. Don’t make a series of sharp turns just to hide the pipe. Use smooth duct and gradual bends where practical, and keep flexible hose as short as the setup allows. If raising a run forces a long, winding path, compare that airflow cost with a simple guard at the exposed spot.
Choose protection for the likely hit
A board edge brushing a duct needs a different fix from a loaded cart striking it. The table compares common options; none should block access to a gate or create a new snag point.
| Protection | Best use | Trade-off |
|---|---|---|
| Move or raise the duct | Regular handling clearance is inadequate | May require rerouting and can add bends |
| Wall-mounted standoff or barrier | Carts, lumber or tool handles hit a fixed wall run | Needs secure mounting; a barrier can reduce aisle width |
| Wooden guard rails | Low-cost protection in a dry shop | Can split, loosen or snag material; inspect regularly |
| Metal guard or bollard | Repeated cart or machine impacts | Costs more and must be anchored to resist the expected load |
For occasional, light contact, a screwed-on wood rail or a short plywood shield can be entirely adequate. Use solid stock, round over exposed corners, and fasten it to framing or a sturdy machine base—not just thin wall paneling. For repeated impacts from a loaded cart, use a barrier designed to take that force and anchor it to the floor or framing. A thin sheet screwed loosely to a wall may look protective but can simply transfer the impact to the duct.
Build a simple guard with clearance
For a vulnerable wall run, make a U-shaped guard from wood or steel, with the open side facing the wall and the duct centered inside. Leave enough clearance that the guard cannot press on the pipe if it flexes or takes a glancing blow. As a practical starting point, allow about 1 to 2 inches between the guard and duct, then increase it if the pipe or its hangers move under hand pressure. Keep the guard separate from the duct supports so an impact does not load the joints.
At a floor-level drop, a short protective sleeve or frame can prevent a board corner from striking the pipe. Don’t tightly wrap duct with padding and call it a guard: padding may hide cracks, hold dust, or interfere with joints. A rigid barrier should take the hit before it reaches the duct, while still leaving the pipe visible enough for inspection.
Use duct-appropriate materials
For a permanent rigid system, choose protection that does not crush or pull on the duct. A steel pipe guard bracket or a fabricated angle-iron frame suits a high-impact location if its anchor points are sound. For a small shop and occasional bumps, lumber and ordinary structural screws are usually cheaper and easier to modify.
Do not use the duct itself as a handhold, shelf support or brace. Avoid fastening guards through the duct wall, and do not put screws where they can protrude into the airflow. If the system uses thin metal pipe, inspect the seams and elbows after any collision; a dented elbow can be more troublesome than a straight section because it may distort a joint.
Support the run and preserve access
Guards protect against impact, but proper hangers keep a run from sagging or pulling apart. Follow the duct manufacturer’s support guidance when available. For a small-shop metal run, supports around every 4 to 6 feet are a reasonable planning range, with additional support near heavy fittings, branches and machine drops. Plastic pipe may need closer support, particularly in warm spaces where it can sag.
Keep blast gates reachable and leave enough room to remove a section for cleaning. A guard that makes a gate hard to operate often gets removed—or encourages the operator to leave the gate open. If you need to protect a gate or branch, use a cage-like guard with an open access side rather than boxing it in.
Inspect after an impact
After a collision, check for a loose hanger, shifted coupling, cracked plastic, crushed flex hose or a gap at a joint. Run the collector and feel around connections for escaping air; a smoke pencil can help locate leaks, but keep smoke away from sparks and open flames. Listen for a new whistle and compare suction at the machine with its usual performance. Repair damage before relying on the system again.
Make inspection easy with visible fasteners and removable guards. If carts regularly strike the same spot, treat that as a layout problem as well as a protection problem: move the parking space, mark a clear travel lane, or relocate the duct. A wall-mounted tool storage rack can also keep long tools off the floor and away from exposed drops. The right fix is the one that prevents routine contact without making dust collection harder to use or maintain.