Dust Collection — validation & limitations

What it calculates

Engineering estimate — this tool uses an accepted simplified model rather than one citable governing standard. Use it for preliminary sizing and verify the final design against manufacturer data or a qualified engineer.

• Multi-branch duct network sizing with ACGIH transport velocity check (St0–St3 dust library + custom dust)
• Fan operating point, shaft power, and next IEC standard motor size selection
• Cyclone separator cut diameter and grade efficiency curve (Lapple 1951 model)
• Baghouse air-to-cloth ratio, filter area, and Kozeny-Carman cake pressure drop
• NFPA 652/654 explosion classification with Kst, MEC and MIT hazard summary and a screening checklist of protection measures (your DHA decides)
• ATEX zone classification per EN 60079-10-2, dust surface-temperature limits per EN/IEC 60079-14, and explosion vent area per EN 14491:2012

Standards this tool applies

• NFPA 652 — NFPA 652/654 St-class classification, a screening list of typical protections, EN 14491 explosion vent sizing, and ATEX zone assessment for industrial dust systems.

Validation evidence — independent reference cases (2)

Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.

• Duct branch loss, baghouse air-to-cloth and fan/motor power

  Agrees

  Source: ACGIH Industrial Ventilation: A Manual of Recommended Practice for Design, Ch. 9 (velocity-pressure method); Colebrook-White friction (ε 0.046 mm); AMCA 201 fan power; EPA Air Pollution Control Cost Manual, fabric filters chapter (A/C = Q/A_cloth)

  Inputs: wood dust 18 m/s, 1 branch 1000 m³/h, L 10 m, 2 × 90° elbows, flanged hood; pulse-jet bags Ø150 × 3 m; trunk 10 m; fan η 65 %, SF_Q 1.10, SF_P 1.15

  Quantity	Reference value	Tolerance
  Branch total pressure loss	698.32 Pa	1 % relative
  Baghouse A/C ratio (7 bags, 9.896 m²)	1.6842 m/min	exact to display rounding (0.001)
  Fan pressure	3617.7 Pa	1 % relative
  Motor power	1.8485 kW (IEC 2.2 kW)	1 % relative

  tests/golden/REF-dust-branch-fan.golden.test.ts

• Explosion class St from Kst at band edges and cyclone FAIL

  Agrees

  Source: NFPA 68 (2018) hazard-class table / NFPA 652 and ISO 6184-1 / VDI 2263-1 St bands (St 1 up to 200, St 2 above 200 up to 300, St 3 above 300 bar·m/s); tool rule per NFPA 654 §7.13 screening

  Inputs: Kst 0, 1, 200, 200.5, 201, 300, 300.5, 301, 800 bar·m/s; custom dust, cyclone-only vs baghouse

  Quantity	Reference value	Tolerance
  St class at Kst 200 / 201	St 1 / St 2	exact (integer class)
  St class at Kst 300 / 301	St 2 / St 3	exact (integer class)
  Cyclone-only verdict at Kst 200	no class FAIL	exact
  Cyclone-only verdict at Kst 201, 300, 301	FAIL	exact

  tests/golden/REF-dust-st-class.golden.test.ts

Limitations

Not checked by this tool

• Deflagration isolation of the connected ducts — Only listed as guidance; design isolation per NFPA 69 / EN 15089 in the dust hazard analysis
• Dust hazard analysis (DHA) of the whole installation — The tool screens; a DHA per NFPA 652 / 660 is still required
• Hood capture velocity and hood design — Only hood entry losses are used; design hoods for capture per the ACGIH Industrial Ventilation Manual
• Duct wall thickness and collapse under fan suction — Not checked; specify the duct gauge and supports per the ACGIH manual or SMACNA
• Junction losses and system balance at the real blast-gate settings — Junction losses are not included separately; balance the system at commissioning
• Vent panel efficiency, vent ducts, the discharge zone and enclosure strength against Pred — The vent area is EN 14491 for a free-venting panel; apply panel efficiency, vent-duct and discharge-zone / recoil checks (EN 14491 / NFPA 68) and verify the enclosure withstands Pred (EN 14460)
• Fan selection on a real fan curve — Only the duty point (flow, static pressure, power) is computed; select the fan on the maker's curve and check the operating point and stability
• Overall cyclone collection (mass) efficiency and emission — Grade efficiency is given at one particle size only; integrate over the measured size distribution and check the emission limit