Case Study: Using Particle Assessment to Determine Ventilation (HVAC) Performance Harry L. Skalsky PhD DABT Skalsky & Associates Becedas Mission Viejo, California (949)

HISTORY Industry - Aluminum Powders & Alumina Abrasives (NIOSH/OSHA) Industry - Aluminum Powders & Alumina Abrasives (NIOSH/OSHA) Indoor Air – Allergens and Irritant Dusts (Air-O-Cell etc.) Indoor Air – Allergens and Irritant Dusts (Air-O-Cell etc.) Hazardous Waste Site – Dust Excursions (Direct Reading Dust Monitors etc.) Hazardous Waste Site – Dust Excursions (Direct Reading Dust Monitors etc.) Exposure Assessment - Particle Counter, Air-O- Cell, and NIOSH procedures. Exposure Assessment - Particle Counter, Air-O- Cell, and NIOSH procedures.

Exposure Assessment (November 2001)

HVAC System Evaluation ( 100% Ambient Air appeared to eliminate a airborne fungal spore problem) Was HVAC System delivering excess fungal spores to the interior ? Was HVAC System delivering excess fungal spores to the interior ?Or Was the “cure”, a fortuitous occurrence ? Was the “cure”, a fortuitous occurrence ?

HVAC – Primary Filter 85% in 3 to 10 micron

HVAC – Final Filter 95% down to 0.3 micron

Collection Equipment Particle Counter HHPC-6 Laser Particle Counter (six channels 0.3 to >10 F m) Two Air-O-Cells at 15 lpm. (5 minutes - outside and 10 minutes - indoor hallway)

Supply Duct Monitoring Balometer – to measure, record and monitor air flow throughout the 30 minute collection time. Balometer – to measure, record and monitor air flow throughout the 30 minute collection time. Plastic Shroud – to prevent mixing with hallway air. Plastic Shroud – to prevent mixing with hallway air. Collection delay - to allow “flushing” of bag prior to sampling. Collection delay - to allow “flushing” of bag prior to sampling.

Particle/Structure Counts 20% versus 100% Outside

Particle Efficiency ( System Average by Particle size)

AOC Structure Efficiency ( System Average by AOC Category)

Intake Location (day1&2)

Intake Location (day1&2) AOC > 2Fm

Hallway Locations (day1) AOC > 2Fm

Supply Locations (day1) AOC > 2Fm

Intake Location (day1&2) AOC – Spores [5 Minute]

Hallway Locations (day1&2) AOC – Spores [10 minute]

Supply Locations (day1&2) AOC – Spores [30 minute]

Conclusions HVAC Filtration Efficiency can be measured by a variety of different factors HVAC Filtration Efficiency can be measured by a variety of different factors Particle Counters and Air-O-Cells yield very different results in the field. Particle Counters and Air-O-Cells yield very different results in the field. Paired Air-O-Cell samples yield a high degree of variability both in spore count (3-68%) and particle count (27-68%). Paired Air-O-Cell samples yield a high degree of variability both in spore count (3-68%) and particle count (27-68%).