Potential concerns for the health of people working with Di [2-ethyhexyl] phthalate (DOP or DEHP) have resulted in studies to determine acceptable substitutes.
As a manufacturer of test equipment, ATI does not control which substitutes may be specified in test standards and practices. However ATI recommends, in order of preference, the following substitute liquids used within the filter testing industry:
- 4 cSt PAO (ATI-PAO 4)
- Ondina / Finevestan
- White Mineral Oil
- DOS / DEHS (Dioctyl-sebacate)
- PEG400/Polyethylene Glycol
- Peanut Oil
- Sunflower Oil
- Cottonseed Oil
In January 1992 the Army Surgeon General’s office gave its approval for the use of 4 centistokes (cSt) polyalphaolefin (PAO-4) in lieu of DOP for U.S. Army filter test equipment. The U.S. Food and Drug Administration followed suit in December 1996 for FDA regulated facilities. Because of these approvals, ATI has placed 4cSt PAO at the top of its recommended list of substitutes.
ATI has performed several studies on the various substitute liquids and found no significant difference in aerosol distribution. However, tests revealed that for the same generator pressures, different concentration values where achieved depending on the substance used.
This should be taken into account if a photometer’s reference feature is calibrated for a liquid other than the one in use.
The second most popular choice has been mineral oil and customer feedback indicates few maintenance problems.
Corn oil is not recommended by ATI as a substitute due to maintenance issues associated with its use.