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INDUSTRIAL PURE WATER APPLICATION

Ultrapure water (UPW) for laboratory grade water

UPW quality guidelines

The ASTM (American Society for Testing and Materials) defines 4 different standard grades for pure water to be used in laboratories.

Parameter

Grade I

Grade II

Grade III

Grade IV

Conductivity µS/cm, 25oC

0.056

1

4

5

Resistivity, 25oC

18.2

1

0.25

0.2

MΩ.cm

TOC (μg/L)

50

50

200

N/A

Total Silica (μg/L)

3

3

500

N/A

Sodium (μg/L)

1

5

10

50

Chlorides (μg/L)

1

5

10

50

pH

N/A

N/A

N/A

58

Special requirements for reagent Grade Water

Distillation or equal process followed by ion exchange and 0.2 µm filter

Distillation or equal process followed by ion exchange

0.45 µm filter

 

Bacteria (CFU/mL)

10/1000

10/100

100/10

 

Endotoxin (IU/mL)

<0.03

0.25

N/A

 

Note: The values in this table are guidelines provided by ASTM. The guidelines will be revised whenever the laboratory industry develops new linewidths Please consult ASTM website (www.astm.org) for updates on these values.

A well designed UPW system requires a strategic selection of technologies and equipment. Depending on the feed water quality and/or the user requirements, different configurations can be applied.