1. In-Situ Filter Testing
ASHRAE GPC 26
In-Situ Filter Testing

2. In-Situ
In Original Position
In Place
As Installed

3. Full Name of Guideline
Guideline for Field Testing of General Ventilation Filtration Devices and Systems for Removal Efficiency In-Situ by Particle Size and Resistance to Airflow

4. Easy and User Friendly

5. Purpose Provide test procedure for evaluating in-situ performance of:
Removal Efficiency of Filter Devices
Removal Efficiency of Filtration Systems
Resistance to Airflow

6. Scope
For General Ventilation Air Cleaning Devices in their End Use Installed Configuration
Site Conditions must meet Minimum Criteria
Not Intended for :
HEPA or ULPA Filters
Portable Air Cleaners

7. Test Equipment Particle Counter Pump Sampling Probes and Lines Valve
3 Range Minimum
.3 to 5 Micron Size Range
Pump
Sampling Probes and Lines
Valve
Air Velocity Instrument
Relative Humidity Instrument
Temperature Measuring Instrument
Pressure Drop Gauges

8. Equipment Setup

9. Procedure Record Conditions Take Fractional Efficiency Data Velocity
Humidity
Temperature
Pressure Drop
Visual Inspection
Take Fractional Efficiency Data

10. Fractional Particle Efficiency Data
Filter Efficiency
Upstream probe within 24”
Downstream probe centered within 12”
Filtration System Efficiency
Upstream same as above
Downstream probe – in front of next component
Other “System” Test – across desired components –(pre, coils, fan, final)

11. Sampling Probe Setup

12. Sampling Method Zero Particle Counter
Concentration Limit – Dilute if over 50% of instrument limit
Isokinetic Flow – within 20%
Prescreen Particle Concentration for Variability – 2 sets of 5 samples within 25%
Take Samples

13. Samples Alternating Upstream/Downstream Number of Samples
Purge between counts
Number of Samples
Minimum of 4 upstream and 3 downstream for each range
More to lower uncertainty
Sample Volume
Greater of 20 seconds or 1 liter

14. Calculations of Fractional Efficiency

15. Reporting Results General Information Which Filter Tested
Number and Type of Filters
Dimensions of Duct
Schematic Drawing showing Location of Sample Points
Equipment Used
When Filters were Last Changed
Other Observations

16. Reporting Results (Cont.)
Airflow
Relative Humidity
Temperature
Pressure Drop
Fractional Efficiency

17. Challenges Isokinetic Flow Turbulent Flow Repeatability of Test
Operator Error or Inconsistencies

18. Timeline
Final Draft by ASHRAE – Quebec
Review ?????

19. Questions