Cleanroom Class Limit

Cleanroom Class Limits

Class limits (maximum allowable particles)

ISO	FED STD 209E	0.1 µm	0.3 µm	0.5 µm	5.0 µm
CLASS 3	1	1,000 / 35	102 / 3	35 / 1
CLASS 4	10	10,000 / 350	1,020 / 30	352 / 10	0
CLASS 5	100	100,000 / 3,500	10,200 / 300	3,520 / 100	0
CLASS 6	1,000	1,000,000 / 35,000	102,000 / N/A	35,200 / 1,000	7
CLASS 7	10,000	350,000	N/A	352,000 / 10,000	70
CLASS 8	100,000	3,500,000	N/A	3,520,000 / 100,000	700

ISO 14644-1 (per cubic meter)

Fed Std. 209 E USA (per cubic foot)

ISO standard requires results to be shown in cubic meters (1 cubic meter = 35.314 cubic feet)

Cleanroom Class 1

540 to 600+ air changes per hour (98%+ ceiling coverage)
ULPA filters (99.9995% on .12 microns)
Gel/Flush grid ceiling systems with raised floors are required
Outside/makeup air to be prefiltered with a HEPA filter

Cleanroom Class 10

540 to 600 air changes per hour (85-90% ceiling coverage)
99.999% on 0.3 microns, with a raised floors
90%+ coverage with low wall returns
Gasketed grids with negative plenums acceptable
HEPA filters on makeup air

Cleanroom Class 100

400 to 480 air changes per hour (60-80% ceiling coverage)
99.99% HEPA filters
Raised floor assures optimal performance. Low wall returns work when they are no further than 12′ from the center of the room¹
Gasketed ceiling grid

Cleanroom Class 1,000

120 to 150 air changes per hour (40-50% ceiling coverage)
99.99% HEPA filter
Gasketed ceiling grid
Raised floor delivers best performance, but low wall returns are very common¹

Cleanroom Class 10,000

45 to 60 air changes per hour (10-20% ceiling coverage)
99.97% or 99.99% HEPAs
Low wall or ceiling returns acceptable in most applications¹

Cleanroom Class 100,000

20 to 30 air changes per hour (5% ceiling coverage)
HEPA filters or 95% HEPAs (95%+ ASHRAE box filters²) located downstream of the HVAC unit
Heat load may require more air changes

1. Room layout with equipment must be evaluated to look for return air paths and possible cross contamination.

2. 95% ASHRAE filters when new may only be 70% and could affect the particle level.

Important point to consider concerning filter coverage:

A 300 sq. ft. cleanroom may need 90% coverage (38 HEPAs) for Class 100 at the “operational” mode, 60% coverage (23) in the “at rest” mode, and only 40% (15) to meet Class 100 at “as built”. The same rules can and do apply to Class 1,000 and Class 10,000 levels.

Services and Products

Cleanrooms

Modular Cleanrooms offers several designs to meet your needs.

Filters

MAC 10 Fan Powered HEPA Filters

Components

Available Cleanroom Components

Design

design

Modular Cleanrooms Services

Furniture

Cleanroom Furniture & Accessories

Supplies

Cleanroom Supplies

Cleanroom Class Limit