5Introduction

Over the past few years there has been an increasing trend to change from previous classifi cation systems used to the ISO classifi cation systems in ISO 14644-1 (see Table 3). However, many companies have continued to use the traditional Class 100, 10,000, 100,000 room classifi cation system from Federal Standard 209-e. In Europe, the GMPs (Good Manufacturing Practice) utilize another system Grades A through D (see Table 4).

EU GMP guidelines are more stringent than others, requiring cleanrooms to meet particle counts at operation (during manufacturing process) and at rest (when manufacturing process is not carried out, but room air handling unit is on). Many global companies, choose to use this classifi cation system. All of these systems are acceptable for use.

INTRODUCTION

UNDERSTANDING CLEANROOM CLASSIFICATIONS

Table 3. ISO 14644-1 Air cleanliness classes for cleanrooms and clean zones.

Source: ISO 14644-1

ISO Classification

Number 0.1 μm 0.2 μm 0.3 μm 0.5 μm 1.0 μm 5.0 μm SI English FormerFED-STD-209E

ISO Class 1 10 2

ISO Class 2 100 24 10 4 8

ISO Class 3 1000 237 102 35 83 M 1.5 1

ISO Class 4 10000 2370 1020 352 832 29 M 2.5 10

ISO Class 5 100000 23700 10200 3520 8320 293 M 3.5 100

ISO Class 6 1000000 237000 102000 35200 83200 2930 M 4.5 1000

ISO Class 7 352000 832000 29300 M 5.5 10000

ISO Class 8 3520000 8320000 293000 M 6.5 100000

ISO Class 9 35200000 83200000 2930000

Table 4. GMP grades - EU classifi cation.

Source: EU GMPs Annex 1 - Recommended Limits for Particulate Contamination

Class

Maximum particles/m3

At Rest At Rest In Operation In Operation

0.5 μm 5 μm 0.5 μm 5 μm Grade A 3,520 20 3,520 20

Grade B 3,520 29 352,000 2,930

Grade C 352,000 2,930 3,500,000 29,300

Grade D 3,520,000 29,000 Not defined Not defined