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Table E-1 (ASHRAE 52.2-1999) Application Guidelines

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Application Guidelines
Std. 52.2 Minimum Efficiency Reporting Value (MERV)	Approx. Std. 52.1 results		Typical controlled contaminant	Typical applications and limitations	Typical air filter/cleaner

20	N/A	N/A	<0.30µm * particle size virus (unattached) Carbon dust Sea salt All combustion smoke, and Radon progeny	Clean rooms, Radioactive materials Pharmaceutical manufacturing Carcinogenic materials, and orthopaedic surgery	HEPA/ULPA Filters >99.999% efficiency on 0.10-0.20µm particles, IEST Type F
19	N/A	N/A			>99.999% efficiency on 0.30µm particles, IEST Type D
18	N/A	N/A			>99.999% efficiency on 0.30µm particles, IEST Type C
17	N/A	N/A			>99.97% efficiency on 0.30µm particles, IEST Type A


16	N/A	N/A	0.30 – 1.0µm particle size All Bacteria Most tobacco smoke Droplet Nuclei (sneeze) Cooking oil Most Smoke Insecticide dust Copier toner Most face powder Most paint pigments	Hospital inpatient care General surgery Smoking lounges Superior commercial buildings	HEPA/ULPA Filters >99.999% efficiency on 0.10-0.20µm particles, IEST Type F> 99.999% efficiency on 0.30µm particles, IEST Type D> 99.999% efficiency on 0.30µm particles, IEST Type C> 99.97% efficiency on 0.30µm particles, IEST Type A
15	>95%	N/A
14	90- 95%	>98%
13	80- 90%	>98%


12	70- 75%	>95%	1.0-3.0µm particles size Legionella Humidifier dust Lead dust Milled flour Coal dust Auto emissions Nebulizer drops Welding fumes	Superior residential; Better commercial buildings Hospital laboratories	Bag Filters Non-supported (flexible) micro fine fibreglass or synthetic media. 300-900 mm (12-36 inches) deep, 6 to 12 pockets. Box filters Rigid style filters 150 to 300 mm (6 to 12 inches) deep may use lofted (air laid) or paper (wet laid) media.
11	60- 65%	>95%
10	50- 55%	>95%
9	40- 45%	>90%


8	30- 35%	>90%	3.0-10µm particles size Mould Spores Hair spray Fabric protector Dusting aids Cement Dust Pudding mix Snuff Powdered milk	Commercial Buildings Better residential Industrial workplaces Paint booth inlet air	Pleated filters Disposable, extended surface, 25 to 125 mm (1 to 5 inches) thick with cotton-polyester blend media, cardboard frame Cartridge filters Graded density viscous coated cube or pocket filters synthetic media Throwaway Disposable synthetic media panel filters
7	25- 30%	>90%
6	<20%	85- 90%
5	<20%	80- 85%


4	<20%	75- 80%	3.0-10µm particles size Mould Spores Hair spray Fabric protector Dusting aids Cement Dust Pudding mix Snuff Powdered milk	Commercial Buildings Better residential Industrial workplaces Paint booth inlet air	Pleated filters Disposable, extended surface, 25 to 125 mm (1 to 5 inches) thick with cotton-polyester blend media, cardboard frame Cartridge filters Graded density viscous coated cube or pocket filters synthetic media Throwaway Disposable synthetic media panel filters
3	<20%	70- 75%
2	<20%	65- 70%
1	<20%	<65%

Note: A MERV for filters other than HEPA/ULPA also includes a test airflow rate, but it is not shown here because it has no significance for the purposes of this table.

* µm is the symbol for micrometers, commonly known as microns,

Note: Conclusive evidence in studies found that common MERV 1-4 filters do little to prevent particulate accumulation on air-pathway components (coils, vanes, heating surfaces).