ISO is the abbreviation of the international organization for standardization. ISO5199, Technical Specification for Centrifugal Pumps, Class II (centrifugal pump technical specification class II), mainly based on the German DIN standard. Its size and performance conform to the ISO2858 standard; the base conforms to ISO3661; the cavity size of mechanical seal or soft packing conforms to ISO3069; the performance test B level conforms to ISO3555, and the C level conforms to ISO2548.

ISO5199 (including equal to or according to the standard of national standards, such as China's GB/T5656) of light load, petroleum, chemical centrifugal pump, driving machine and auxiliary equipment and puts forward the basic requirements in the design, manufacture, inspection, testing and delivery status etc.. The applicable parameter range of this standard is roughly as follows:

（1）Rated discharge pressure             ≤1.96mpa（G）；
（2）Medium temperature                   <260℃；
（3）Driving power                               ≤110kw;
（4）Maximum speed                           <3600r/min；
（5）Rated lift                                       ≤120m；
（6）Maximum inspiratory pressure     ≤0.5MPa(G)；
（7）Maximum impeller diameter        ≤333mm。

ISO5199 chemical centrifugal pump is called ISO pump;

ISO pumps require less in material, design, manufacturing, and testing than API pumps, so the reliability is relatively poor and, of course, the price is much cheaper. This kind of pump meets the requirements of general chemical use and is often used in occasions where the requirements of flammable and dangerous are not too high.