Modeling particle loss in ventilation ducts

Journal Article · Tue Apr 01 04:00:00 EST 2003 · Atmospheric Environment

DOI:https://doi.org/10.1016/j.atmosenv.2003.07.016· OSTI ID:917808

Sippola, Mark R; Nazaroff, William W

Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 {micro}m are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 917808
• Report Number(s): LBNL--52449; BnR: NN2004000
• Journal Information: Atmospheric Environment, Journal Name: Atmospheric Environment Journal Issue: 39-40 Vol. 37; ISSN ATENBP; ISSN 0004-6981
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR
DEPOSITION
DUCTS
FILTRATION
INDOORS
OFFICE BUILDINGS
ORIGIN
OUTDOORS
PARTICLE SIZE
VENTILATION
VENTILATION SYSTEMS