Poly Alpha Olefin (PAO) Used in HVAC Validation

Poly Alpha Olefin (PAO) is used for HVAC qualification in pharmaceuticals. PAO is used as a replacement of the DOP (Dioctyl Phthalate) that was used for this purpose for a long time. Dioctyl Phthalate is found as a carcinogen (cause cancer) for the human. Scientists were trying to find a material to replace the a long time.

DOP for Finally in 2001 Japan Air Cleaning Association (JACA) published a guideline to replace the DOP with PAO. It gives the equal performance to the DOP and doesn’t have any harmful effect on health. FDA also clearly says that alternative aerosols are also acceptable but they should not promote the microbial growth in the area. Therefore, it is recommended to replace the Dioctyl Phthalate with Poly Alpha Olefin (CAS 68649-12-7). The size of PAO generated aerosol ranges from 0.1 to 1.0 μm.

The PAO aerosols are generated by the aerosol generator and passed through the HEPA filter then the integrity is checked using a photometer. 99.97% particles having a size larger than 0.3 μm should not be passed through HEPA filters. Poly alpha olefin is a polymer of alpha-olefin. Alpha-olefin is a class of olefins those have a double bond between first and second carbons of the polymer chains.?

PAO is a mixture of the dimers, trimers and tetramers of the 1-octane, 1-decane and 1-dodecane. Poly-alpha-olefins have good lubrication properties and greater viscosity than mineral oils. Poly alpha olefins are also used as synthetic lubricants and as a coolant in radiators. It should be protected from UV light and direct sunlight.