Aerospace dust collection systems

Wet collection vs. dry collection for aerospace metals

Your single most important design decision is wet vs. dry, and NFPA 660 draws a hard line based on material reactivity:

• Titanium and magnesium: wet collection is effectively required. These metals burn at extreme temperatures, and dry filter media can’t safely contain an ignition event — titanium can also self-ignite through friction or static. Wet collectors remove the fuel-air mixture entirely.
• Aluminum: either wet or dry is permitted, but dry systems need full explosion protection — venting panels, chemical isolation, and suppression. Many shops choose wet for aluminum anyway because it simplifies compliance and drops the explosion-protection maintenance.
• Wet machining of titanium and aluminum: when these alloys are machined with flood coolant or high-pressure through-spindle coolant — common on 5-axis mills and turn-mill centers — the primary airstream is oil mist rather than dry combustible dust. The equipment family shifts to CNC oil mist collectors, with combustible-dust controls reserved for any dry secondary operations (deburring, grinding, finishing).
• Composites (carbon fiber, fiberglass): dry cartridge collectors with HEPA secondary filtration work well. Not combustible metals, but highly abrasive and respirable.

If you machine both titanium and aluminum on the same floor, your system has to handle the most reactive material present. We typically design segregated systems — separate ductwork runs and collectors for each material — to meet both the NFPA 660 metals provisions and AS9100 contamination control. For the full side-by-side, see wet collectors vs. dry collectors.

What NFPA 660 requires for aerospace metals

NFPA 660 has been the unified combustible dust standard since January 1, 2026 — it brings the former NFPA 484 (combustible metals), 652, and 654 under one code. Here’s what it means for your system:

• Dust hazard analysis (DHA): required before any system design. It identifies the combustibility of your specific dust — Kst, minimum ignition energy, minimum explosible concentration — and sets the protection strategy. We manage that process for you, from testing through documentation. See how we handle DHA →
• Equipment design: collectors rated for the specific metal dust — correct housing material, grounding and bonding against static, and wet collection or explosion protection as appropriate.
• Housekeeping: documented dust accumulation limits on all surfaces. Your system has to capture at the source well enough to prevent accumulation — which drives ductwork velocity, hood design, and capture efficiency.
• Ductwork: minimum transport velocities to prevent settling (typically 4,000–4,500 FPM for metal dust), spark-resistant construction, grounding throughout, and conductive flex connections at machines.

If you want the plain-English version of the standard, read NFPA 660 explained.

Common aerospace applications

CNC titanium machining — 5-axis mills, lathes, and turn-mill centers throwing fine titanium dust and chips. When the operation runs dry, wet collection with a pre-separation cyclone for chip recovery is the compliant path, plus source-capture hoods and fume extraction arms at operator-accessible areas. When the operation runs wet with high-pressure coolant — common on aerospace 5-axis platforms machining Inconel and titanium — the primary airstream is coolant mist, which requires CNC oil mist collectors rather than dry combustible-dust equipment.

Aluminum wing-skin fabrication — routing, drilling, and trimming large aluminum panels. High-volume dust needing 10,000+ CFM, with explosion-protected dry or wet collection depending on your preference and insurer.

Grinding and deburring — your highest-risk operation: fine particles, sparks, and heat in the dust stream at once. Spark detection and suppression is mandatory; wet collection is strongly recommended for any combustible-metal grinding.

Composite trimming and drilling — carbon fiber and fiberglass dust from cured structures. Not a combustible-metal hazard, but OSHA PELs still apply, so HEPA filtration is standard to protect your team and nearby CMMs.

What an aerospace system costs

You get real numbers for capital planning, not a “call for a quote” runaround:

• Single-machine wet collector (titanium/magnesium): $15,000–$35,000 installed
• Multi-machine wet collection (4–8 stations): $60,000–$150,000 installed
• Explosion-protected baghouse (aluminum, 5,000–20,000 CFM): $45,000–$120,000 installed
• Central system with pre-separation, spark detection, and multiple material zones: $150,000–$400,000+

Your dust hazard analysis is priced separately, per node — typically $400 to $700 per node, which lands most facilities between $9K and $85K+ depending on how many dust-generating points you have. We manage that engagement for you.