European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges 16th December 2014 Renaissance Brussels H...
European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges 16th December 2014 Renaissance Brussels Hotel, 19 Rue du Parnasse, Brussels Brussels Ballroom, 11:25‐12:25
CEN/TC 195 "Air filters for general air cleaning" Introduction to M/461 related activities
P. Tronville Politecnico di Torino, Turin, Italy Chairman CEN/TC195; ISO/TC142
CEN/TC195 "Air filters for general air cleaning" • • • • • •
Formed in 1990 ‐ current secretariat: UNI (since 2007) Secretary: Anna Martino (since 2007) Chairman: Paolo Tronville (since 2006) Currently five Working Groups (WG1, 2, 4, 5, 6) WG6 "Execution of Mandate M/461" Several standards currently developed under Vienna Agreement with ISO/TC142 (ISO lead) • Two Work Items related to M/461 developed under Vienna Agreement (CEN lead)
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
2
Normative background • No standard available to measure filter media efficacy in removing airborne nano‐sized materials or nano‐particles • Air filtration test methods concerned about determination of "most penetrating particle size" (MPPS) and minimum efficiency • EN 1822:2009 series does not require to measure below 100 nm (developed during '90s) • New filter media MPPS in the nano‐size range (i.e. below 100 nm) • Instrumentation available on the market measuring down to 2.5 nm • Two open issues: – At some particle size penetration starts increasing again (2 nm?) – Electrostatic effects influence strongly filter media efficiency and vary very much during service life of air filters 16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
3
Airborne nanoparticle filtration 1) Nanoparticles are being manufactured from a wide range of materials and causing concerns for workplace safety 2) Two opposing filtration theories: • Increasing efficiency with decreasing size by Brownian deposition • Decreasing efficiency with decreasing size due to thermal rebound
Japuntich et al. (2007), J. Nanoparticle Research, 9, 93–107. 16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
Kim and Okuyama, (2006) J. Nanoparticle Research 8: 343‐350 4
State of the art in measuring below 100 nm
Automated Filter Tester
Filter tester for respirator testing
Condensation particle counters respirator testing
Polydisperse oil or NaCl particles
Lower detection limit: 2.5 nm
Size range: 15‐800 nm Detectors: CPCs
Detectors: CPCs 16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
5
CEN/TC195 M/461 related efforts • EN “Test method to measure the efficiency of air filtration media against spherical nanomaterials in the 20‐500 nm size range” • CEN/TS “Test method to measure the efficiency of air filtration media against spherical nanomaterials in the 3‐30 nm size range” • Develop a robust test method (some very critical points) • Validate and revise (more than one lab) • 3 years of pre‐normative work • 6 years in total to get one EN standard (20‐500 nm) and one technical specification (3‐30 nm) published • Likely to be published also as ISO IS and TS • Involvement in CEN/TC195 of a few non European experts
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
6
Pre‐normative work team
Reference lab Air Quality & Particle Research ETHZ/EMPA, Switzerland Supporting lab Particle Technology Lab University of Minnesota, USA Round‐robin test labs Camfil, Sweden Politecnico di Torino, Italy Unifil, Switzerland 16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
7
Review of instruments and materials
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
8
Preliminary test methods
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
9
Filter media types and test conditions Courtesy of Prof. Wang Velocity (cm/s)
Pressure drop (Pa)
NP 1 m (Nuclepore, Sterlitech)
2
439
5
NP 3 m (Nuclepore, Sterlitech)
2
Filter type
Velocity (cm/s)
Pressure drop (Pa)
2
0
1084
5
0
93
2
0
G3
M5 5
232
5
4.5
2
0
2
2.5
GX (8mm)
M6 5
2
5
10
2
0
2
4.5
5
18
GX (11mm)
F6 5
16.12.2014
Filter type
2 P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
10
ETH and UMN comparison (GX filter, 8mm) Courtesy of Prof. Wang GX filter, 8mm
GX filter: silver particles
GX filter: DEHS particles
GX filter: silver particles
GX filter: DEHS particles
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
11
Nanoparticle properties relevant to air filtration • • • • • • •
Form and size distribution Aerodynamic drag Density Count in sampled flows Bounce and adhesion Brownian diffusion Electrical charge distribution
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
12
Aerosol nanomaterial forms: simple to very complex
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
13
Even relatively simple non‐spherical forms can be characterized in many ways
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
14
Future challenges • Air filtration efficiency as a function of – Particle shape – Particle material • Air filter media made by electrostatic enhanced material – Why it loses efficiency when exposed to nano‐particles – How to measure the change of air filter media properties • How to extend the standard for measuring the performance of air filter media to full scale air filters (ventilation air filters for workplace safety) • How to make the test methods as quick and easy to perform by industry
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges
15
Thank you for your attention!
16.12.2014
P. Tronville – European Conference on Standardization for Nanotechnologies and Nanomaterials: Opportunities and Challenges